set 4 (Nasi)

[cyrus1345]

1.a 16 year old needs c section, who will consent?
girl herself/mother/ boyfriend/attorney?
a 14 year old needs abortion, who will consent?
girl/other/ boyfriend/ attorney?


16 yr with csection.....mother
14 yr with abortion , herself

2.which one of the following is not a risk factor for osteoporosis/?
Caucasian or Asian women

Advanced age

Early or surgically induced menopause

Chronic corticosteroid use

Maternal history of osteroporosis


Prolonged bed rest

High alcohol consumption

Low calcium intake

obesity

Cigarette smoking

High protein/phosphate intakes

High caffeine consumption

Physical inactivity



obesity


3.a 60 year old male presents to er with sudden onset of ripping chest pain, radiating to the back, on examination. on examination, pr=120. bp 90/60. pulses weak, dullness on left base of chest, no rales. mumer heard in aortic area.what is the next best step in diagnosis?what is the most specific and sensitive test for diagnosis/.?

next best is x ray
and most sensitive and specific is TEE



4.43y native american presants with sudden onset of symmetric flaccid paralysis in all limbs while he was retiring after a meal.He is a hypertensive not on any Rx.No focal neuro signs.
Hb 12, tlc 12000 , plt 190000 , bun 14 , creatinine .8, bilirubin 1.1 , S.Ca 9mg{ N is 8.5 to 10}, K 3.1 mmol [ n is 3.2 to 4.9], Mg 1.1 [normal is 1.3 to 1.8]
What needs to be looked into next.
What is the Dx and Rx?


botulism what type of food intake/drug neuromuscular blocking agents hyperbaric oxygen ventilation ,antibiotics

5.43y native american presants with sudden onset of symmetric flaccid paralysis in all limbs while he was retiring after a meal.He is a hypertensive not on any Rx.No focal neuro signs.
Hb 12, tlc 12000 , plt 190000 , bun 14 , creatinine .8, bilirubin 1.1 , S.Ca 9mg{ N is 8.5 to 10}, K 3.1 mmol [ n is 3.2 to 4.9], Mg 1.1 [normal is 1.3 to 1.8]
What needs to be looked into next.
What is the Dx and Rx?


pt native american, post prandial, K just low[may even be normal], flaccid paralysis in limbs, no features of stroke or cranial nerve palsy.
Botulism starts with eye and by the time all limbs are involved pt goes into hypoventilation.His HT is unrelated here.
Do thyroid studies[native american and asian], can presant without clinical thyrotoxicosis but low TSh.
Tx with betablockers which may aso help his HTN.K may be needed if levels are too low



6./c of the ffg is not thought to improve long term survival in a pt w/stable congestive heart failure
a. spironolactone
b. digoxin
c. cavedilol
d. enalapril
e. smoking cessation

ans was digoxin. I got this for a MCQ book I was doing at the bookstore. Forgot write down the full explanation


7.a lesion of w/c of the ffg cranial nerves may result in hyperacusis?
a. trochlear
b. facial
c. vestibular branch of the vestibularcochlear nerve
d. glossopharyngeal
e. vagus


facial
8.w/c of the ffg is not generally asst'd w/ thrombocytopenia
a. alcohol
b. aspirin
c. sulfonamides
d. heparin
e. quinidine


b- aspirin, it only inhibits plt aggregation, it doesn't cuase thrombocytopenia


9.deficiency of w/c of the ffg vit causes petechial bleeding?
a. B1
b. B2
c. C
d. Folate
e. K


Vit c deficiency, petechial bleeding due to blood-vessel fragility


10. 80 year old man has memory loss, language deterioration, impaired visuospatial skills, poor judgment, indifferent attitude, but preserved motor function. he has inability to sleep and he presents to you for treatment of his insomnia. what is the best drug for him?

short acting benzo s lorazepam


11.50-year-old woman with diabetes. ulcer of medial forefoot what is thenext best step in investigation?

NEXT best step is xray


Follow Ups:


12.**************** MECHANICAL VENTILATION **************

The science of mechanical ventilation is to optimize pulmonary gas exchange; the art is to achieve this without damaging the lungs.

FIRST LET'S DIFFERENTIATE:
- Mechanical ventilation: the ventilator is active and the patient passive
- Assisted Ventilation: the patient initiates and may or may not participate in the breath.

Note: For general purposes, both will be referred to as Mechanical Ventilation throughout the chapter.

Mechanical Ventilation could be throughout intubation (invasive) or a tight-fit mask (non-invasive).

WHAT IS A VOLUME VENTILATOR?
term used because you set a volume and the machine delivers that volume, at whatever pressure necessary (up to a limit). The ventilator blows that volume at a certain FLOW. Flow can be:

- Volume targeted and pressure variable: set the parameter of the volume. It will be delivered with increasing pressure until the set volume is given. The problem is: barotrauma.

- Volume variable and pressure targeted: set the parameter of the inspiratory pressure, tidal volume will flow within that range. The problem is: since delivery of a set volume is not guaranteed, gas exchange can vary, making dangerous hypercapnia or alkalosis possible. Indicated for conditions where risk of barotrauma can be instantly life-threatening. Example: ARDS.

THE MECHANICAL RESPIRATORY CYCLE :
- Air is pushed in under POSITIVE PRESSURE, to a degree far greater than the patient could deliver on his or her own; air delivered under positive pressure is physiologically distinct from spontaneous breathing, where air enters the lungs by virtue of a slight negative airway pressure. The concept of POSITIVE PRESSURE is that a baseline pressure is applied throughout the cycle to maintain alveolar recruitment.

- Exhalation is passive, utilizing the recoil nature of the chest to let air be exhaled; passive exhalation is physiologically the same as during spontaneous breathing.

WHAT'S THE DIFFERENCE BETWEEN CPAP AND PEEP?
They virtually refer to the same thing. PEEP is the positive pressure you set for the end of expiration. CPAP refers to when inspiration starts, the pressure starts from the PEEP and on up. Continuing Positive pressure throughout the entire cycle instead of intermittently at the end of expiration is called Contiued Positive Airway Pressure CPAP.

WHEN DO YOU DECIDE THAT A PATIENT SHOULD BE INTUBATED?
1. Loss of gag/cough reflex e.g. head injury with GCS <8 (to prevent massive aspiration).

2. Airway obstruction: acute laryngeal edema – e.g. inhalation burn, Ludwig’s angina, epiglottitis.

3. Anticipated loss of control of the airway: anticipated laryngeal edema– e.g. neck trauma, acute stridor etc.

Either indication must be based SOLELY on the clinical examination, although ABG's are often helpful to assure that mechanical ventilation is not necessary.

WHEN DO YOU INDICATED MECHANICAL VENTILATION IN ADDITION TO INTUBATION?

Take home message:
- Apnea
- Impairment of alveolar ventilation (assessed by PaCO2>50mmHg) and/or oxygenation (assessed by PaO2<50mmHg) are the only physiologic reasons for instituting mechanical ventilation. IN CHRONIC LUNG DISEASE, HIGH pCO2 IS SOMETIMES ACCEPTABLE BUT NOT CRITICALLY LOW pH (ph<7.1 is an indication to mechanical ventilation).
Again, rule of thumb, correlate with clinical setting. Treat the patient not the numbers.

Although mechanical ventilation can lead to better cardiac, renal, or cerebral function, the basic goal for its use must be to improve the PaO2 and/or the PaCO2 or TO REDUCE THE FiO2 OR THE MECHANICAL WORK needed to maintain blood gas values at an acceptable level.

Official Criterias are:
1- Apnea
2- Impaired alveolar ventilation (as assessed by PaCO2) when accompanied by one or more of the following:
a. Depressed mental status
b. Increasing fatigue
c. Reduced PaO2 that cannot otherwise be corrected
d. Severely deranged pH that cannot otherwise be corrected (below 7.1 is considered an indication for mechanical ventilation)
e. Compromise of upper airways (e.g., by secretions)

3- Low PaO2 (e.g., less than 60 mm Hg):
a. that cannot be improved with an FIO2 less than 0.50, and
b. that is causing symptoms or seriously impairing bodily function

CLINICAL-BASED PROBLEM:
WHICH (ONE OR MORE) OF THE FFG CASES SHOULD BE INTUBATED AND MECHANICALLY VENTILATED BASED ON THE ABOVE?

a. A 50-year-old man is comatose from drug overdose. PaCO2 is 51 mm Hg, PaO2 is 76 mm Hg, and pH is 7.31 while breathing room air.

b. A 29-year-old man is alert but in respiratory distress; he is breathing 42 times/min. PaCO2 is 38 mm Hg. pH is 7.42, and PaO2 is 47 mm Hg while breathing 60% oxygen through a face mask.

c. A 61-year-old woman who has severe emphysema is alert but is in moderate respiratory distress; her respiratory rate is 24/min. PaO2 is 75 mm Hg while breathing nasal oxygen at 2 L/min, PaCO2 is 59 mm Hg, and the pH is 7.37. Her chest x-*** is clear.

d. A 29-year-old woman is suffering from diabetic ketoacidosis. Her pH is 7.10, PaCO2 is 26 mm Hg and PaO2 is 110 mm Hg while breathing room air.

e. A 31-year-old drug addict responds briefly to the administration of Narcan (a narcotic antagonist) by opening her eyes and crying out and then lapses back into a state of semi-stupor. PaCO2 is 31 mm Hg. pH is 7.38, and PaO2 is 89 mm Hg while breathing nasal oxygen at 3 L/min.

WHEN FACED WITH A BORDERLINE ABG AND POSSIBLE MECHANICAL VENTILATION, HOW DO YOU EVALUATE?

It is essential to deduce what part of the respiratory apparatus is malfunctioning.

1- Is it failure to ventilate (is the PCO2 > 50mmHg), or failure to oxygenate (is the PO2 <50mmHg)? Remember that a low O2 is much more significant than a high PCO2, but is frequently easier to treat.

2- In essence the problem is one or more of the following:

* The chest cage is not effective in guaranteeing adequate minute ventilation.
* Air is not able to pass effectively from the upper to the lower airway – increased airway resistance.
* Gas is unable to pass effectively from alveoli to capillaries – due to some obstruction in the interstitial space.
* Ventilation is being wasted – alveoli are being ventilated but not perfused: dead space ventilation or more air than the blood can utilize (high ventilation/perfusion (V/Q) ratio).
* Blood flow is inadequately utilized and blood is passing through the lungs without coming into contact with aerated alveoli: perfused but not ventilated – shunt or ventilation falls behind blood flow (low V/Q ratio).

HOW DO WE INITIATE MECHANICAL VENTILATION?
The ventilation strategy is determined by whether the patient has failure to ventilate or failure to oxygenate. The first problem is managed by increasing the patients minute ventilation, the second by recruiting collapsed lung units and controlling mean airway pressure.

Every patient who is intubated is in need of a rest, and usually patients are started on controlled modes (see below Modes of ventilation).
- If failure to ventilate or protect the airway was the problem, controlled volume ventilation is used, to correct the respiratory acidosis, being careful not to damage the lung (be mindfull of the pressures generated).
- If failure to oxygenate is the problem, usually controlled pressure modes of ventilation are used, and carefully titrate the CPAP and the pressure control levels to set targets.

While the choice of control mode is probably irrelevant (assist control (AC) or intermittent mandatory ventilation (IMV)), it is important that the patient’s spontaneous breaths are supported, which means adding pressure support to (S)IMV.

HOW ARE MECHANICAL VENTILATORS CLASSIFIED?
1) How the ventilator knows how much flow to deliver = CONTROL = Volume Controlled , Pressure Controlled, or Dual Controlled.

2) We determined how much flow and at what pressure. Now how long does it stay there? = CYCLING: how the ventilator switches from inspiration to expiration:
Time cycled, Flow cycled, OR Volume cycled.

3) What causes the ventilator to cycle to inspiration? = TRIGGERING = Ventilators may be time triggered, pressure triggered or flow triggered (see next note).

One type of ventilators to be familiar with is: FLOW-BY = FLOW-TRIGGERED RESPIRATOR (The patient's own breath triggers the breath to be delivered at set standards of volume and pressure).

4) We determined the volume, pressure, time, trigger, Now the questions is how is that breath going to be delivered to the alveoli? = BREATHS = Mandatory (controlled = which is determined by the respiratory rate), Assisted (as in assist control, synchronized intermittent mandatory ventilation, pressure support), or Spontaneous (patient sucks up his/her own breath).

5) Very much linked to the precedent, ventilators got smarter now with MODES OF VENTILATION:

+> CMV = Controlled Mandatory Ventilation. dOESN'T allow spontaneous breathing. Many anesthesia ventilators operate in this way.
+> AC: Assist-Control = Allows the trigger of the breath, and the patient to make own effort but the flow/volume/pressure are controlled breaths.
+> IMV: Intermittent Mandatory Ventilation = Patient initiate own breath and sucks up air, but also breath controlled by ventilator is delivered. The problem? "stacked breaths" where there is build-up of high-pressures and therefore alveolar stretching and damage. The solution? Breaths may also be synchronized to prevent "stacking".
+> High Frequency Ventilation = where mean airway pressure is maintain constant and hundreds of tiny breaths are delivered per minute.

WHY ARE THEY SO MANY DIFFERENT WAYS TO VENTILATE A PATIENT?

- It all started in mid-1950's with the polio epidemic. Patients suffering with this virus die from asphyxia - respiratory muscle paralysis and failure to ventilate. Medical students were assigned to manually ventilate paralysis victims until restoration of neuromuscular activity occurred. "old ventilators" called "iron lungs" used to provide negative pressure about the rib-cage allowing sucking up air. But they were of little value since the disease was not inability to ventilate but that to oxygenate.
- Then came the Pressure Controlled Ventilators.
- During the 1970s and 1980s ventilators were developed which allowed patients breathe spontaneously, initially with assisted breaths (assist control ventilation) and subsequently with spontaneous breathing limbs – (synchronized) intermittent mandatory ventilation (SIMV). The latter was the first mode to allow partial ventilatory support and thus gradual liberation from the ventilator.
- During the 1990s widespread concern developed about ventilator induced lung injury. Accumulating evidence revealed that larger tidal volume, low PEEP, ventilation strategies were damaging the lungs. This has led to the development of lung protective ventilator strategies (renewed interest in plateau pressure limitation and increasing mean airway pressures).
- Dual modes, combining pressure limitation with guaranteed tidal volume, have been developed. Physicians are now demanding more control over gas flow than before - hence the development of active exhalation valves, dynamic inspiration valves, rise time control, automatic tube compensation and, of course, waveform analysis.
- Modern ventilators deliver enhanced patient interactivity using better triggering sensors, and more comfortable spontaneous breathing - even in inverse ratio ventilation.

HOW DO YOU GO BY MECHANICAL VENTILATION SETTING....PRACTICALLY?

A- Oxygenation. Arterial oxygen content should be maintained at 60 mm Hg or higher, or saturations at 90% or higher. Generally, initiate mechanical ventilation with an FiO2 of 100%, then taper 10% every 10 to 15 minutes to find the lowest FiO2 necessary to maintain adequate oxygenation. An FiO2 of greater than 60% for over 24 hours has been associated with lung injury. PEEP may be added to decrease the A-a gradient, allowing a lower FiO2 while maintaining oxygenation.
For all practical purposes, a patient who is intubated mainly for hypercapnia will usually be adequately oxygenated with an FIO2 under 0.40. A patient intubated because of severe hypoxemia or during cardiopulmonary resuscitation may need an initial FIO2 of 1.00. Blood gas measurements should be obtained in the first half hour after treatment, and adjustments made to keep the PaO2 between 60 and 90 mm Hg at the lowest FIO2 possible.

B- Respiratory rate and Ventilation (Measured by minute ventilation = tidal volume x respiratory rate, and is reflected in the PCO2). Increases in minute ventilation will cause a decrease of PCO2. Goals of ventilations should be to maintain a pH (as determined by PCO2 and underlying diseases) of 7.3-7.4.
The respiratory rate is set by using a dial on the machine.
- For controlled ventilation, the rate equals the total number of ventilator breaths the patient will receive.
- For assist control ventilation, the rate represents the minimal number of breaths; depending on the inspiratory sensitivity (also set by the machine), the patient may initiate more than the minimal amount.
- For intermittent mandatory ventilation, the respiratory rate is also the total number of ventilator breaths per minute; however, between the machine breaths, the patient may breathe spontaneously.


C- Permissive hypercapnia. In certain situations (e.g., ARDS) it may be permissible to allow the PCO2 to rise (permissive hypercapnia) to decrease injury from ventilation as long as the patient maintains hemodynamic stability and oxygenation. This has been shown to decrease mortality in some cases (e.g., ARDS).

D- Minute ventilation is the product of tidal volume and rate; it is approximately 5 to 10 L/min or 100 ml/kg/min.

E- Tidal volume (Vt) and Inspiratory Pressure limit. Initial volume is 8 to 10 ml/kg. A large Vt improves gas exchange and prevents atelectasis. However, it may decrease venous return higher volumes may increase risk of barotrauma. A smaller Vt may be required if PEEP is added.
For patient for whic it is expected to have some sort of airway obstruction, the inspiratory pressure limit will protect patient from further complications.
Example: setting the tidal volume for delivery of 700 cc might achieve a peak airway pressure of 30 cm H2O; a pressure limit of 50 cm H2O can be set at the same time. If, for example, the endotracheal tube slips into the patient's right main stem bronchus, the machine will attempt to deliver 700 cc to just one lung (half the previous lung volume), and the peak inspiratory pressure will acutely rise. Conceivably the elevated airway pressure could rupture the right lung or cause other damage. Instead, however, when 50 cm H2O airway pressure is reached, the machine stops inspiration and an alarm sounds, perhaps after delivering only 400 cc. With this warning, the therapist or nurse can quickly investigate the problem. The alarm will sound each time airway pressure reaches the preset inspiratory pressure limit.

F- Inspiratory time and flow. The peak inspiratory flow rate determines how fast each breath will be delivered to the patient and is therefore a determinant of inspiratory time. Adjust inspired flow rate to maintain a ratio of inhalation time (I:E ratio) to exhalation time of 1 to 1.5 in most patients. and is usually achieved with a peak inspiratory flow rate between 40 and 70 L/min.
Patients with airway obstruction (asthma, COPD) may require additional time for exhalation. This can be accomplished by decreasing inspiratory time, or by decreasing respiratory rate.

G- Positive end-expiratory pressure (PEEP) may increase compliance and decrease the work of breathing by preventing atelectasis, and thereby decreasing shunting. It is usually begun at 3 to 5 cm H2O and increased in small increments. High levels may result in decreased venous return and severe hemodynamic compromise. Other negative consequences include overventilation, barotraumas, and elevated intracranial pressure. Cardiac output should be measured if there is an indication of problems because it may increase or decrease with increased PEEP.

H- Peak airway pressure reflects the pressure required to overcome airway resistance and is the peak pressure during the inspiratory cycle. The alarm limit should be set 10 cm H2O above this. If the peak inspiratory pressure increases, you need to consider obstruction in the ET tube, bronchospasm, decreased lung compliance, or a pneumothorax from barotrauma.
* Sedation and neuromuscular paralysis allow the patient to rest, decrease anxiety, and ensure better compliance with the ventilator. However, periodic interruption of sedation (if tolerated) reduces the total number of days on a ventilator.
Initial therapy includes midazolam, diazepam, lorazepam and propofol. Dosages should be titrated to desired effect, with monitoring of hemodynamic and respiratory status.
* Neuromuscular paralysis is occasionally necessary if sedation fails, but patients should still be sedated. Monitoring alarms must be functioning because ventilator malfunction is rapidly fatal if the patient is paralyzed. Immediate, short-term paralysis (3 to 7 minutes) can be achieved with succinylcholine 1 mg/kg IV. For long- term paralysis use non-depolarizing agents such as pancuronium, vecuronium, or cis-atracurium. If repeated dosing or continuous drips are necessary, consider nerve-stimulation testing to avoid over-medication. Prolonged use of these agents, especially in continuous infusions, is associated with prolonged (days to months) muscle weakness and ventilatory dependence. Use of nerve-stimulators can decrease the dose of paralyzing agents while maintaining adequate control. If necessary, a neostigmine-atropine combination can be used to reverse the non-depolarizing agents.

CLINICAL SCENARIO:

A 60*year* old patient is in the hospital for treatment of a myocardial infarction. During the night she suffers acute pulmonary edema and requires cardiopulmonary resuscitation. Before the patient is intubated and mechanical ventilation is begun, her blood gas measurements show pH of 7.06, PaCO2 of 61 mm Hg, and PaO2 of 50 mm Hg while breathing 100% oxygen delivered by manual ventilation with an Ambu bag. The patient's estimated body weight is 50 kg (110 Lbs). What initial ventilator settings would you choose for the following:

a. FIO2
b. Tidal volume
c. Inspiratory pressure limit
d. Respiratory rate
e. Peak inspiratory flow rate
f. Would you provide PEEP?

Answer:
Inability to Oxygenate secondary to Alveolar exchange problem (V/Q mismatch: high perfusion low ventilatin)
a. FIO2: 100%
b. Tidal volume: 8-10cc/kg. W=55Kg. Choose higher and readjust per subsequent ABG's. Vt= 500cc/min
c. Inspiratory pressure limit: empirically 40cmH2O since patient has pulomnary edema and is liekly to have airway obstruction and high airway pressure.
d. Respiratory rate: Start with an empirical rate of 10-14/min.
e. Peak inspiratory flow rat: 40-70 L/min to acheive I:E ratio of 1 to 1.5.
f. Would you provide PEEP? Yes. Alveoles are full of fluid and will tend to collapse. To ensure continued alveolar recruitment, PEEP must be delivered. Lung compliance is adequate but FiO2 is 100% at first so, PEEPis 15-20 cmH2O and readjust once you decrease FiO2.

A 72*year*old man with severe chronic obstructive pulmonary disease is in the intensive care unit. His pH is 7.24, PaCO2 is 84 mm Hg, and PaO2 is 58 mm Hg while breathing 28% oxygen through a Venturi mask. His chest x*ray suggests severe emphysema. Despite optimal drug therapy, his blood gas measurements cannot be improved, and he is almost unarousable. To prevent respiratory arrest, he is intubated and given mechanical ventilation. His estimated body weight is 70 kg (150 lbs). What initial ventilator settings would you choose for the following:

a. FIO2
b. Tidal volume
c Inspiratory pressure limit
d. Respiratory rate
e. Peak inspiratory flow rate
f. Would you provide PEEP?


Answer:
a. FIO2: It is an oxygenation problem. FiO2 should be modest. 40% is a number to start with.
b. Tidal volume: Modest as well, enough to correct acidosis 500 - 600cc/min with a RR of 10-14l/min
c Inspiratory pressure limit: 50 is a good limit.
d. Respiratory rate: 10-14 and readjust
e. Peak inspiratory flow rate 60-70 L/min since it's a COPD guy and should be allowed more time for expiration.
f. Would you provide PEEP? Lung compliance is increased. 15-20 cmH2O still stands for this patient as well, to allow proper compliance to ventilatory oxygenation.

A comatose 20*year* old patient is brought to the emergency room following an overdose of sleeping pills. Because of very shallow respirations and cyanosis, the patient is intubated before his blood gas results are known. Initial ventilator settings include a tidal volume (VT) of 700 cc, a respiratory rate (RR) of 12/min, and an FIO2 of 0.50. The patient has no spontaneous breathing. Blood gas results obtained (1) before intubation and (2) 20 minutes later show the following:

pH---PaCO2---PaO2 FIO2 VT RR

(1) 7.10 79 38 Room air 0 0

(2) 7.25 56 117 50% oxygen 700 12

Following the second blood gas analysis, would you change the FIO2, the tidal volume, or the respiratory rate'? If so, what settings would you choose?

Decrease the FiO2 by 10% and redraw ABG's. Patient shows sings of improvement. No reason to change other settings.


WHAT ARE THE COMPLICATIONS OF MECHANICAL VENTILATION?

A- VENTILATOR-ASSOCIATED PNEUMONIA: Continuous subglottic aspiration of secretions reduces the incidence of nosocomial pneumonia. A semirecumbent position in bed also will minimize the risk of ventilator-associated pneumonia. A bacteriologic diagnosis should be aggressively pursued in ventilator-associated pneumonia and will reduce mortality.

B- Stress ulcer prophylaxis. Sucralfate, H2 blockers, and proton-pump inhibitors have all been shown to be effective. However, sucralfate may be associated with a lower rate of ventilator associated pneumonia.

C- DVT prophylaxis. Heparin 5000 U SQ Q12h or LMW heparins (enox-aparin 40 mg SQ QD or 30 mg SQ Q12h) are preferred, unless contraindicated (coagulopathy, thrombocytopenia, active bleeding, recent or future surgery). Compression stockings and intermittent pneumatic devices (TEDS and Kendals) are also effective.

WHEN DO YOU WEAN THE PATIENT OFF OF MECHANICAL VENTILATION?

Guidelines for weaning from mechanical ventilation:
- An awake, alert patient.
- PO2 >60, with an FiO2 <50%.
- PCO2 acceptable and a pH in normal range.
- PEEP <8 cm H2O.
- Minute ventilation less than 10 L/min.
- Patient is able to generate maximum voluntary ventilation without retractions.
- Patient is able to generate a peak negative inspiratory pressure of at least 20 cm H2O.

HOW DO YOU ACHEIVE WEANING OF MECHANICAL VENTILATION?
The most effective method of weaning to discontinuation is spontaneous breathing trials (SBT).
Otherwise:
1- Pressure-support method:
Switch from an assisted mode of breathing to pressure support, setting pressures to generate Vt similar to the assisted volumes with a ventilation rate less than 20. Gradually decrease the inspiratory pressure until 8-10 cm H20 above expiratory pressure. If patient can maintain adequate volumes with a ventilation rate of less than 20 for 30-60 minutes, consider extubation.

2- T-tube method:
(A T-tube allows the patient to breathe through an endotracheal tube without assistance from the ventilator.) Have the patient use a T-tube with humidified oxygen. If the patient tolerates this for 1 to 4 hours without deterioration, discontinue mechanical ventilation. If the patient fails the attempt, resume mechanical ventilation and consider IMV method (below) for weaning.

3- IMV method. Gradually decrease the number of assisted respirations in 1 or 2 breath increments over 30- to 90-minute intervals. Monitor ABGs and vital signs. When an assisted rate of <4 breaths/min is achieved, consider a brief T-tube trial. If the patient remains stable, discontinue mechanical ventilation. If the trial fails, increase assisted rate until patient stabilizes. Repeat attempt the following day with a more gradual decrease in the rate of assisted breaths.

HOW DO YOU KNOW WHEN TO D/C WEANING TRIALS AND RESUME MECHANICAL VENTILATION?

When:
- pH <7.3, PCO2 >50, PO2 <60.
- The patient becomes anxious, fatigued, demonstrates increasing respiratory distress, or develops significant arrhythmias or hemodynamic deterioration.

Clinical Scenario:
A decision is made to wean a 67* year* old man from the ventilator. Before weaning is begun, the machine is in the assist* control (AC) mode. The patient is initiating 16 breaths/min and is receiving 700 cc/breath. He is switched to IMV at a rate of 12/min and within a half hour is noted to be in respiratory distress with a total respiratory rate (machine initiated plus spontaneous) of 20/min. Blood gas measurements obtained before and after the change to IMV are shown below. How would you explain the changes? Should you D/C the weaning?

Assist* control 16 (700 cc) 0 7.45 38 78 0.40
IMV 12 (700 cc) 8 7.39 47 65 0.40

Ans: Patient was in Assist Control with a controlled rate of 16 and a tidal volume of 700cc. Switching to IMV caused both hypercapnia and acidosis (inability to ventilate)=> Increase minute ventilation, and hypoxia (inability to oxygenate)=> Give PEEP and increase FiO2. No need to D/C weaning yet at this time, since the ABG's are not yet critical.

This decision should be supported by more thant those numbers:

What are the consequences of Weaning?
- The single most traumatic event for the patient is conversion from positive pressure to negative pressure ventilation.
- To extubated a patient, they need to be awake, able to cough and protect their airway.
- Although the ventilator only appears to support on organ system, the lungs, this is not in fact the case. For a patient to self ventilate, many body systems must be functioning: the cardiopulmonary apparatus, the central nervous system, the nerves that supply the diaphragm (including the neuromuscular junctions), the muscles themselves. Moreover the patient must be willing to breath and maintain their own functional residual capacity (not if there is diaphragmatic splinting due to pain). There must be room in the abdomen for the diaphragm and lungs to move into. There must be adequate hemoglobin to deliver oxygen to the tissues.
- A reintubation rate of 10% is acceptable. Patients deserve a trial of extubation, and many will do well in spite of poor mechanics (you must use clinical judgment).

CLINICAL SCENARIOS:
I) A 22 year old male found collapsed in the street, pinpoint pupils, respiratory rate of 5 and a PCO2 of 70 mmHg, PO2 60mmHg

Hints: Is it ventilatory failure or oxygenation failure (is the PCO2 > 50mmHg, is the PO2 <50mmHg). Remember that a low O2 is much more significant than a high PCO2, but is frequently easier to treat.
If it is ventilatory failure, where is the injury – in the brain (the medulla), in the spinal cord, in the peripheral nerves, at the neuromuscular junction, in the muscle itself or in the chest cage?
If the problem is oxygenation failure, where is the injury: is it in the blood supply, at the alveolar-capillary interface or in the upper, middle or lower airways?

II- A 47 year old male with a two week history of upper respiratory tract infection is admitted with a history of bilateral lower limb weakness and shortness of breath. His forced vital capacity is 1 liter and his pCO2 is 70mmHg and pO2 60mmHg.

III - A 74 year old female is admitted unconscious, GCS 3, Cheyne Stokes breathing pattern, in atrial fibrillation, BP 170/100mmHg, PCO2 70mmHg, PO2 60mmHg.

IV- A 35 year old male with a history of asthma complains of acute severe left sided chest pain, and becomes acutely dyspneic: PCO2 is 47mmHg, PO2 49mmHg.

V- A 54 year old female, 36 hours post total abdominal hysterectomy, becomes confused and hypotensive – PO2 is 45mmHg, PCO2 is 29mmHg.

VI- A 16 year old female presents with a two month history of severe fatigue, exercise intolerance, shortness of breath and weight loss. She is admitted through the ER in extremis, with a PCO2 of 70mmHg and a PO2 of 50mmHg.

VII- A 73 year old male is discharged from the intensive care unit, following a three week admission for sepsis following a perforated appendix. He has been short of breath all evening. Now he is severely distressed and his chest is moving up and down in a seesaw manner. This patient had a collapsed right lung on chest x-***.

VIII- A 67 year old male is admitted with an acute asthmatic attack. 4 hours after admission you are called because he is hypoxemic, finds it difficult to get air in, his chest is hyperinflated and he is becoming hypercarbic.


ANSWERS:

I) This man has ventilatory failure, as you can see from his high CO2. He is also somewhat hypoxemic, which is not surprising, as CO2 will displace O2 from the alveolus when it builds up (we know this from the alveolar gas equation: PAO2 = PiO2 – PaCO2/R). The combination of meiosis and bradypnea immediately suggests narcosis, which can be reversed, at least temporarily, with naloxone. The mechanism of his respiratory failure is thus loss of respiratory drive due to opioids reducing the sensitivity of the respiratory center to carbon dioxide. Intubate and ventilate in controlled mode. Start with RR 10-14, and a tidal volume 7-10cc/kg. FiO2 of 100% with CPAP, then taper 10% every 10 to 15 minutes to find the lowest FiO2 necessary to maintain adequate oxygenation. Inspiratory flow rate; generally set between 60 and 100 l/min (the faster the flow rate, the quicker inspiration and the longer the patient has to exhale).

II- Patient has high pCO2 = Inability to Ventilate.
This patient has ventilatory failure, as evidenced by his inability to clear carbon dioxide. His diagnosis turns out to be Guillain-Barre syndrome, which is characterized by motor, sensory and autonomic neural demyelination and thus neuropathy, which usually eventually reverses. The low FVC is a sign of poor physiological reserve, and this patient requires controlled mechanical ventilation. Oxygenation is OK, so FiO2 should be modest and readjusted until stabilization of O2 Sat and ABG's. Tidal volume 8-10cc/kg. Add PEEP to allow lower FiO2.

III- This patient is failing to ventilate and failing to protect her airway. A comatose patient with this breathing pattern is a brain stem stroke until otherwise proven. The cause is either a bleed (hypertension) or an embolus (atrial fibrillation). Mechanical ventilation in this circumstance is invariably futile, yet indicated if patient is full code.

IV- This patient is acutely hypoxemic secondary to a barotrauma. He is not adequately clearing carbon dioxide, which should be much lower in view of the degree of hypoxemia. This suggests that there is a shunt present. The major concern here is that the patient has had an acute pneumothorax and there is a loss of hypoxic pulmonary vasoconstriction. He requires urgent placement of a chest tube. Intubation is not necessary at this stage. Pneumothoraces are relatively common in young asthmatics. The main problem is an inability to ventilate (high pCO2) with an associated problem: inability to oxygenate (high pO2) due to shunt.

V- This is, in many ways the opposite to case 4. The patient is hypotensive, hypoxemic and hypocarbic after pelvic surgery. The most likely diagnosis is a massive pulmonary embolism from the pelvic veins. The problem is failure of oxygenation due to a massive amount of wasted ventilation (dead space ventilation), due to obstruction of blood flow. In view of her hypoxemia, she should be intubated in IMV mode since patient can breathe on her own, along with Heparin therapy and other measures for PE management.

VI- This patient has a ventilatory abnormality. She presents with a combination of fatigue, and the inability to clear CO2, suggesting muscle weakness. The diagnosis is Myasthenia Gravis, which is characterized by anti-acetylcholine receptor antibodies, and thus effective neuromuscular blockade. Mechanical Ventilation on IMV mode with increased minute ventilation, increased FiO2, PEEP.

VII- The combination of recent discharge from ICU, which indicates potentially a recent extubation, and paradoxical breathing, is strongly suggestive of upper or middle airway obstruction. The cause may be in the oropharynx (tongue or dentures obstructing breathing), the larynx (laryngeal edema or stenosis) or below the larynx. One thing to strongly consider is accumulation of secretions or inspissation of mucus, due to ineffective bronchial toilet (the patient probably has a very poor cough). Intubate patient for pulmonary toilet and removal of impacted secretions.

VIII- Failure to Ventilate due to outflow obstruction: the patient is attempting to ventilate at high lung volumes where the lungs are least compliant.
This patient has severe outflow obstruction and gas trapping. Due to the high resistance to ventilation, air is slow to exit the lungs, and the patient feels uncomfortable, he attempts to actively exhale and this causes dynamic airways collapse, causing further airway closure. Some airways may remain closed during the entire ventilatory cycle, and oxygen is not replenished – and there is a ventilation-perfusion mismatch. This man is exhibiting signs of acute gas trapping (auto PEEP) and hypercarbia, indicating worrisome loss of physiological reserve.
He needs to be intubated and PEEP applied to his airway in excess of the auto-peep generated: he should be treated with pressure support ventilation: this mode provides limitless flow to match the patient's demands.


References:
- http://www.ccmtutorials.com/rs/mv/
- http://www.ccmtutorials.com/scenarios/intvent/index.htm
- http://www.vh.org/adult/provider/fam...er04/03-4.html
- http://www.mtsinai.org/pulmonary/boo...m#introduction



13.A 42-year-old previously healthy male presents to the emergency room complaining of lightheadedness after passage of large, dark, bloody bowel movement. He reports previous episods of epigastric discomfort releaved with antacides. He takes no medicarions, and denies recent NSAID or alcohol use. He smokes 2 packs of cigarettes daily. On physical excam his blood pressure is 95/50, his pulse is 105, hematocrit is 24.
He is pale and his abdomen is soft and nontender.

What is the most likely diagnosis and your diadnostic test of choice. EXPLAIN YOUR ANSWER
a Gastric ulcer-upper GI endoscopy
b Duodenal ulcer-upper GI series plain films
c Diverticulosis-colonoscopy
d Duodenal ulcer-upper GI endoscopy



Answer id d.For this age group bleeding peptic ulcer is more likely. When I was answering this q, I thought Gastric og dougenal ulcer? I know that increase acid production causes doudenal ulcer but not gastric one.
Though I thought that pain in both cases are releaved by antacids


14.a 56-year-old alcoholic presents with hematemesis. Despite aggressive resuscitation with fluid and blood, he can not be stabilized. What is the most likely diagnosis?
Please,txplain Why do you think it is the most likely diagnosis?
a Bleeding esophageal varicies
b Mallory-Weis tear
c Boerhaave's esophagus
d Chronic gastritis
e Gastric Lymphoma



Correct answer a. Read leeward college explanations. They are even better than in the book

Clinical vignette is too brief (clues given: alcholonic w/massive UGI bleed nonresponsive to blood and fluids). Need more details. Here are my reasons.

a Bleeding esophageal varicies - possible, but other than being an alcoholic, there is no clues to suggest its dx. But if I had to choose among these choices, this would be my ans.

b Mallory-Weis tear - most cases resolve spont, although there are some cases that are refractory and will not respond to fluids and blood.
c Boerhaave's esophagus - this px needs agressive sx tx. It will not respond to fluids and blood. But the clnical vignette gives no clues to suggest its dx
d Chronic gastritis - possible, but unlikely. No clues in the vignette to suggest it.
e Gastric Lymphoma - possible, but unlikely. No clues in the vignette to suggest it.




15.a 14 year old girl presents to your office for regular check up. she is a known diabetic for the past 5 years, is on insulin. on examination, pr=72, b.p.120/80/ h/l nad.her mother tells you that the girl had her first periods the preceeding week.what will u do?
1. continue same dose of insulin
2.increase insulin
3. decrease insulin
4.stop insulin.


increase the dose is the anser. any inputs will be appreciated

16.HTN + MI
HTN+ DIA
HTN..black
HTN+LVh
HTN+Dm+black


HTN + MI - BB or ACEI
HTN+ DIA - ACEI
HTN..black - Thiazides
HTN+LVh - ACEI
HTN+Dm+black - ACEI


15.With HIV being such a hot topic on the USMLE, I post high-yield facts I encounter. Please refer to the post: ODD HIV case posted on July18 for HIV and Syphilis association.

HIV associated Nephropathy Pearls (HIVAN)

- Mostly African Americans (So and so, that in the absence of renal biopsy, and if the patient is white, think of other diagnoses)

- Patient may present with Uremic Encephalopathy with confusion, new-onset seizure (Management of seizure with subsequent treatment using phenytoin), asterixis etc.

- Labs: Uremia, massive proteinuria in the nephrotic range with little to ne edema

- Order Ultrasound: which in contrast with usual shrunken small kidneys of End-Stage Renal Disease, in HIVAN, kidneys are ENLARGED!!

- Confirm with Renal Biopsy: FOCAL SEGMENTAL GLOMERULAR SCLEROSIS is the most typical one.

Management: Antiretroviral Therapy is the most important feature. It not only slows the progression but may in fact reverse it. Hemodialysis should also be started.
Of note: Encephalopathy is a sign of rapidly changing nephro status either deteriorating ir improving (encephalopathy on first hemodialysis = Dialysis dysequilibrium Syndrome).
ACE-I also have been used successfully to further slow progression. Corticosteroids have also been used but with caution because of the advanced stage of AIDS already for the patient.

Differential: Hep B and Hep C associated nephropathy, Heroin Associated Nephropathy.

Reference:
- Medscape (posted from the AIDS reader)
New Onset Seizures as an Initial Presentation of End-Stage Renal Failure in Patients With HIV/AIDS
Toyin F. Olatinwo, MD; Ross G. Hewitt, MD
8/2002



16.- ABDOMINAL GUNSHOT WOUND
19yo gan member is shot in the abdomen with a .38 caliber revolver. The entry wound is in the epigastrium, to the left of the midline. The bullet is lodged in the psaos muscle on the right. He is hemodynamically stable, and the abdomen is moderately tender. Which of the ffg is most appropraite next step in management?
A- Close Observation
B- Emergency US
C- CT abdomen
D- Diagnostic Peritoneal Lavage
E- Exploratory Laparotomy

Ans: E. The abdomen is full of important strudtures that should not be penetrated, solid organs that can bleed, and hollow viscera that will spill fluids in to the peritoneum. The rule of abdominal gunshot wounds is simple: They belong to the OR before any sign of peritonitis starts.

B- GUNSHOT WOUNDS TO THE EXTREMITIES:

A 25 yo man is shot with a .22 caliber reveolver. The entrance wound is in the anterior, lateral aspect of his thigh, and the bullet is seen on X-*** films to be embedded in the muscles posterolateral to the femur. The ER departement MD cleans the wound thoroughly. Which of the following is the most appropriate next step in management?
A- Tetanus prophylaxis
B- Doppler Studies
C- Arteriogram
D- Surgical Explration of the femoral vessels
E- Surgical Removal of the embedded bullet.

Ans: A. Tetanus prophylaxis is first. In wounds of the extremities, the main concern is the possibility of major vascular injuries. They can be evaluated by Doppler, arteriogram, or surgical exploration. But one should know the femoral artery is located anteromedial in the upper thigh, and eventually becomes central when it becomes the popliteal. It is NOT located in the lateral aspect where the bullet is located here. Removing the bullet, although obligatory in movies, is not necessary if it's not threatening to erode some vital structure.

A 25 yo man is shot with a .22 caliber revolver. The entrance wound is in the anteromedial aspect of the upper thigh, 5 cm below the groin crease. The exit wound is in the posterolateral aspect of the thigh, half way between the great trochanter and the knee. He has palpable pulses in the dorsum of his foot and in the posterior tibial artery behind the malleolus. The popliteal pulse is reported normal by one examiner, but canno be felt by another. There is no hematoma under the entrance wound, and blood is oozing from both wounds, but not at an alarming rate. He is hemodynamically stable. Neurologic examination of the leg is normal. X-*** films show the femur to be intact. In addition to local wound care and the appropriate tetanus prophylaxis, which of the following is the most appropriate next step in management?
A- Discharge home
B- Digital exploration of the wounds in the ED
C- Admit to observe for development of complications
D- Arteriogram
E- Formal surgical exploration of the area in the OR

Ans: D. Arteriogram. Anatomic proximity to major vessels is the main criterion to suspect vascular injury in gunshot wounds of the extremities. Although absent pulses and an expanding hematoma make such injury virtually certain (and dictate the need for surgical exploration), the presence of normal pulses and the absence of a hematoma does NOT rule out vascular injury. Only an arteriogram can provide the necessary reassurance.

C- GUNSHOT WOUNDS TO THE NECK:

A young man is short in the upper part of the neck with a .22 caliber revolver. Inspection of thew entrance and exit wounds indicates that the trajectory of the bullet is all above the levl of the angle of the mandible, but below the skull. He is fully conscious, and neurlogically stable. A steady trickle of blood flows from both wounds, and it does not seem to responds to local pressure. He is again hemodynamically stable. Which of the following is the most appropraite next step in diagnosis?
A- Continued Clinical observation
B- Barium Swallow
C- Arteriogram
D- Endoscopy
E- Surgical exploration

Ans: C. In gunshot wounds og the upper part of the neck, the main concern is the possibility of significant vascular injuries. The area is too high to involve the aerodigestive tract, and it is also rather difficult to explore surgically. Arteriograms offer the best way to assess the extent of the injuries, and also provides a way for embolization of major arteries that might be bleeding significatnly.

A 25-year-old African American man arrived at the emergency room approximately 30 minutes after sustaining a single gunshot wound to the left posterior cervical region. His chief complaints were neck pain and the inability to move any extremity. Systolic blood pressure before his arrival was reported to be 90 mm Hg (palpatory). Neurologic examination showed intact cranial nerve (II through XII) functions, with flaccid paralysis of all four extremities except for bilateral forearm flexion, which was possible against gravity. Sensory examination was intact for pin prick and light touch throughout. Deep tendon reflexes were absent bilaterally. Rectal sphincter tone was decreased, with preserved bulbocavernosus reflex. The bullet entrance wound was in the left posterior cervical region, above and medial to the left scapula. The exit wound was midline in the anterior aspect of the neck. A bullet fragment was palpable in the left anterior aspect of the neck, lateral to the cricoid cartilage. A large left anterior neck hematoma was present. Both carotid pulses were palpable, and there were no carotid bruits.
What is the next step in management?

Ans: Surgery.
Findings on the initial workup were consistent with a zone II neck injury (see below), resulting in hypotension and neck hematoma as well as cervical spine injury with an incomplete motor deficit at the C5 level. This is an absolute indication for neck exploration. He was taken immediately to the operating room. Surgical exploration of the left anterior cervical region revealed an extensive hematoma and a lacerated left external jugular vein, which was ligated. The hyoid bone was fractured and repaired.


D- GUNSHOT WOUNDS TO THE CHEST:

A 27 yo man is shot point blank with a .22 caliber revolver. The entrance wound is in the anterior chest wall, just to the left of the sternal border, at the level of the 4th intercostal space. There is no exit wound. He is diaphoretic, cold, shivering, and anxious, and is asking for a blanket and a drink of water. His blood pressure is 65/40 mmHg, and his pulse is 145/min, and barely perceptible. He has large, distended veins in his neck and forehead. He is breathing adequately and has bilateral breath sounds. He is neurlogically intact. Which of the folloing is the most likely diagnosis?
A- Extrinsic cardiogenic shock due to pericardial tamponade
B- Extrinsic Cardiogenic shock due to tension pneumothorax
C- Hemorrhagic shock
D- Intrinsic cardiogenic shock due to Myocardial injury
E- Vasomotor Shock

Ans: A. Obviously, patient is in shock and the distended veins identify the type as cardiogenic. Given the location of the injury, pericardial tamponade is the obvious mechanism.

A 19yo gang member is shot once with a .38 caliber revolver. The entry wound in the left mid-clavicular line, two inches below the nipple. The bullet is lodged in the left paraspinal muscles. He is hemodynamically stable, but he is drunk and combative. PE is diffult to do. What is the next step in management? (no choices)


Ans: CXR (chest tube if needed) which is the usual for a chest injury, in addition to Exploratory laparotomy which is the usual for an abdominal injury. The point is to remind of the boundaries of the abodmen. Although it sounds like a chest wound, it is also abdominal. The belly begins AT the nipple line. The chest does NOT END AT THE NIPPLE line though. Belly and chest are stacked up and separated by a dome.

E- SOME FACTS AND REVIEW

1- The Wounding Capacity of a Bullet
It is related to the following factors: Kinetic Energy, Angle at impact, Bullet type, and Tissue Density.
The consequences are generally:
+> Laceration and Crushing: projectile displacing the tissues in its track. They are recognized as the primary wounding mechanism produced by handguns.
+> Shock Waves: compression of tissues that lay ahead of the bullet. Produced by high velocity projectiles (not from handguns).
+> Cavitation (permanent and temporary): also from even higher velocity projectiles. When a missile enters the body, the kinetic energy imparted on the surrounding tissues forces them forward and radially producing a temporary cavity or temporary displacement of tissues. The temporary cavity may be considerably larger than the diameter of the bullet, and rarely lasts longer than a few milliseconds before collapsing into the permanent cavity or wound (bullet) track.

2- Classification of Gunshot Wounds
+ Penetrating : Missile is retained in tissue, Entry wound is typically small and ragged
+ Perforating: Missiles pass completely through the target, Entry wound is comparable to size of missile, and Exit wound is often considerably larger
+ Avulsive: Small entrance comparable to missile size
Exit wound is usually gaping with large amount of tissue loss.

3- Treatment of gunshot injuries
Primary - resuscitative efforts as well as establishment of airway and restoration of hemodynamics
Secondary - depends on the location.

NECK TRAUMA:

A significant number of patients of neck trauma die at the scene and others on the way to hospital. Patients arriving shocked and bleeding are resuscitated and usually undergo urgent surgery with repair or ligation of the bleeding vessels. Progressive neurological deficit calls for rapid evaluation and management.
Stable patients, on the other hand, can be subjected to whatever diagnostic modalities are required to diagnose the extent of injury accurately.

Neck wounds are classified as zones I, II and III.
+> Zone I injuries are those that are below the cricoid cartilag
+> zone II are above the cricoid cartelage but below the angle of the mandible
+> zone III are above the angle of the mandible extending to the base of the skull.

Most institutions explore zone II injuries routinely. In zone I and III more definite evidence of injury is required, which can be obtained by endoscopy as well as angiography before exploration is embarked upon because of the difficulty in gaining access in zones I and III.

GUNSHOT WOUND TO THE SPINE:
Gunshot wounds (GSW) are the 3rd most common cause of traumatic spinal cord injuries in the U.S. civilian population.
The injury from a gunshot wound could be either direct or indirect. Indirect injury results from shock waves or secondary fragments damaging the neural elements. Direct injury is a consequence of the projectile crossing the spinal cord and/or canal causing compression, contusion, or laceration of the spinal cord/ nerve roots, with or without laceration of the dura.
Overall most studies in the literature recommend a conservative (non-surgical) approach to GSWs to the spine, as surgery has not been shown to improve much the neurological status, but some authorities beleive that removing the bullet still gives the best chance to recovery. Indeed, it is still highly controversial.
The firm indications for surgical intervention are usually:
+> Progressive neurological deficits
+> Persistent cerebrospinal (CSF) leaks
+> Incomplete neurological deficits with radiographic evidence of neural compression (especially in the cervical spine and cauda equina).

Reference:
www.rcsed.ac.uk/journal/vol43_2/4320019.htm
www.uic.edu/depts/doms/rounds-6.html
http://www.medschool.lsumc.edu/Nsurgery/GSWSp.html
http://www.medscape.com/viewarticle/410823_4


17.Which of the following has been strongly associated with preterm labour.
1.bacterial vaginosis.
2.candidiasis.
3.tricomonosis
4.group B steptococcus.



the answer is bacterial vaginosis.I read somewhere that group B step is found normally in female genital tract.Any comments?


18.Complications of TPN: Central Vein nutritional support occur in up to 50% of patients. They can be divided into: CATHETER RELATED, AND METABOLIC.

CATHETER RELATED:
- Pneumothorax/Hemothorax
- Arterial LAceration
- Air Emboli ++++++
- Brachial Plexus Injury
- Catheter Thrombosis +++/ Catheter-related Sepsis +++
Patient with TPN using indwelling catheter, who develops fever without apparent source => Change line immediately, and culture tip of old one.

METABOLIC: Exam related are in my opinion
- Hyperglycemia: Caused by too rapid an infusion of dextrose, or use of steroids. Reduce infusion rate, add insulin if needed.
- Hyperchloremic nonketotic dehydration: reduce chloride.
- Azotemia (Creatinine normal): Reduce protein
- Acalculous Cholecystitis: mostly from biliary stasis. Give fat orally if possible
- Zinc Deficiency: +++++ PATIENT DEVELOPS RASH, CHANGE OF TASTE, AND HAIR LOSS. Check for possible diarreha or bowel fitula. Increase Zinc intake.
- Magnesium: muscle weakness and tremor, Decreased DTR and respiration.
- Other: Copper, Selenium (cardiomyopathy)

Source:
CMDT
http://www.gray-ink.com/quillen/gi.html

19.A 46 y/o woman presents with a one year Hx of pruritus and a two-month history of jaundice and tan colored stools. She consumes two mixed drinks per day. There is a previous history of IV drug abuse. The most likely diagnosis is:
A. Alcoholic cirrhosis
B Cirrhosis secondary to hepatitis C
C Cirrhosis secondary to hepatitis B
D. Primary biliary cirrhosis
E. Hemochromatosis
Please explain your answer. Thanks


answe is D- PBCPBC
clues from the vignette:
Seen in females 40-60yo
increase bile acids leads to pruritus
increase bilirubin leads to jaundice



20.A 50 y/0 lawyer is seen in your clinic for an insurance physical exam. He is feeling well overall but says that over the past 2 months he has been suffering from increased fatigue and has lost 10 pounds. He is putting in long hours at work because of an important medical malpractice case he is involved in. He takes no medications. His past medical history is significant only for a splenectomy following a gunshot wound he sustained in Vietnam. You find no significant abnormality on his physical exam except for a surgical scar on his abdomen. His laboratory exam reveals a WBC count of 15,000/µl, a Plt count of 550,000/µl, and a Hct of 52%. You review the patient's blood film and notice a leukocytosis with Howell-Jolly bodies in his RBCs. At this point you should:

A. Do a bone marrow biopsy to rule out leukemia, particularly with a history of fatigue and weight loss.
B. Reassure the patient that his leukocytosis is expected and is secondary to his splenectomy.
C. Since the patient is a malpractice lawyer and you are afraid of being sued, do a bone marrow biopsy to be sure that nothing is wrong.
D. Start the patient on antibiotics just in case he may have an infection.
E. Obtain a stool sample to determine if he has parasites

Well guys, that why I posted this q ( I thought also the most logical answer would be Bx ), but based on my resource answer is B with no explanation... Please discuss this..


21.A 26 y/o diabetic woman is seen in the ER for sore throat. Rapid strep test is positive for streptococcal pharyngitis and she was started on ampicillin 500 mg four times a day. Three days later, she develops hematuria associated with a low grade fever. On physical examination, she has a maculopapular rash and a temperature of 101oF. Laboratory studies show: serum creatinine 3.6 mg/dl, WBC 8,700 with 56% PMN, 25% lymphs, 3% monos and 15% eosinophils. Urinalysis: pH 6.2, protein 2+, blood 3+, 65 RBCs/HPF, 20-30 WBCs/HPF, 3-4 WBC casts/HPF. Hansel's stain is positive for eosinophils. The most likely diagnosis would be:
A. Diabetic nephropathy
B. IgA nephropathy
C. Acute interstitial nephritis
D. Acute pyelonephritis
E. Acute post-streptococcal glomerulonephritis


answer is C- AINAIN - MAIN clue "...positive for eosinophils..."




22.A 22 y/o old man presents with the complaint of recurrent blood in his urine. He states that it usually occurs when he gets "the flu". He has no other complaints and he has been in good health otherwise. He is not taking any medication and has no drug allergies. On P/E, B.P. is normal and he has no edema. U/A reveals trace proteinuria, several dysmorphic RBCs and few RBC casts. BUN is 12 mg/dl and serum creatinine 0.6 mg/dl. Which one of the following is the most likely diagnosis?
A. Good pasture Syn.
B. Wegener’s dis.
C. IgA nephropathy
D. Focal segmental glomerulosclerosis



Answer is C- IgA nephropathy

no sign of pulmonary hemorrhage so goodpasture excluded
pts with IgA nephropathy have recurrent hematuria,and gross hematuria 24-48hr after exercise,vaccination or GI,pharyngeal infection


23.A 70 y/o Asian male presents with hematochezia, he has stable V/S. lower endoscopy was unsuccessful due to active bleeding.
What’s the next best step?
A- abd. CT
B- barium enema
C- Tech. 99 scan
D- Exploratory laparatomy


E- Small bowel x-ray




Answer is C- Tech 99 scan. Orbit has a good explanation.


Follow Ups:


C- Tech. 99 scan
to find out the source of bleeding


facts
to remmeber
1consider cause of lower gi bleed as upper gi bleed
2.angigraphy ortc 99 scan is therapeutic as well
so i would go for angiography in an actively bleeding patient
actually first step would be ng tube/endoscopy, then colonoscopy. if colonoscopy is not possible angiogram or radionuclidescan


24.A 55 year old insulin dependent diabetic woman was brought to Casualty by ambulance. She was semi-comatose and had been ill for several days. Past history of left ventricular failure. Current medication was digoxin and a thiazide diuretic.

Results include: K+ 2.7, glucose 67 mmols/l, anion gap 34 mmol/l

Arterial Blood Gases
pH 7.41

pCO2 32 mmHg

pO2 82 mmHg

HCO3 19 mmol/l

1: Acid-Base disorder: IT's a mixed disorder. The disorder usually starts with alkalosis and then acidosis ensues. The result is a "normal" pH. COMPENSATION NEVER "NORMALIZES" pH. It's always close to normal.

#2: PAtient has been sick for a while, May be had an infection which precipitated DKA. She has hyperglycemia (67. Normally it's below 6), which corroborates it. The anion gap is high, so we can concude that it is metabolic acidosis.

#3: No creatinine level is given, no sodium level, and no calcium level. One must rule out if patient is having some degree of renal failure due to long-standing diabetes which would aggravate the acidosis.

#4: The patient is on thiazide diuretic. The most common side effects of thiazide diuretic is hypochloremic hypokalemic metabolic alkalosis. In addition, dehydration probably increased plasma concentration of Thiazide, aggravated by the possible renal failure the patient might have been experiencing, which would explain the profound hypokalemia instead of the usual hyperkalemia you would have in a simple DKA episode.

#5: Why is it important to make those speculations? Stopping the offending drug and replacing it with another diuretic would probably correct some of the electrolyte imbalances. In addition, management of DKA differs in patients with renal failure. In the presence of renal failure administration of large amounts of fluid is unnecessary and generally is contra indicated; Overhydration is a concern in adults with compromised renal or cardiac functions and in elderly with incipient congestive heart failure. Consequently, hemodynamic assessments must be made in an intensive care setting in order to administer adequate quantities of fluid while avoiding overhydration that may complicate the condition. Hemodialysis may be needed in some occasions to treat acidosis in this situation.

Another example of mixed disorders is salycilate intoxication whereby the first change is respiratory alkalosis, and the next is metabolic acidosis as the ASA accumulates. The result is a normal pH. Correct me if I am wrong.


25.In the dark,a pt’s right pupil is 3mm greater in diameter than the left pupil.In bright light,the right pupil is only 1mm larger than the left pupil.Which pathway contains the lesion?
a:afferent sympathetic
b:efferent sympathetic
c:afferent parasympathetic
d:efferent parasympathetic


b:efferent sympathetic
anisocoria


26.A 2yo child has a 2day history of fever&pain in the right ear.Ph.E reveals bulging&marked erythema of the right tympanic membrane as well as bilateral scleral injection and purulent conjunctivitis,what’s the pathogen most likely responsible?


Follow Ups:


Nontypeable H influenzae disease
Nontypeable strains of H influenzae frequently cause otitis media, sinusitis, conjunctivitis, and bronchitis. Conjunctivitis is usually bilateral and purulent and often occurs in association with acute otitis media (ie, conjunctivitis-otitis syndrome).


26. visit a 5day old son who brings by her mother bcoz of red,tearing eyes with yellow sticky discharge that prevents him from opening his eyes after sleeping.A Gr stain of purulent material show gr- diplococci.Next stp of Mx?
A:topical silver nitrate
B:topical erythromycin
C:systemic ceftriaxone
D:systemic erythromycin



systemic ceftriaxone.
earliest is chemical, neisseria[2nd week], chlamydia, last to appear[5 weeks.
and if it were chlamydia, then oral erythromycin

C:systemic ceftriaxone
gonococcal conjunctivitis
topical silver nitrate&erythro for prophylaxis at birth
systemic erythro for chlamydial conjunctivitis that usually occurs 5-14days after birth


27.A 52 yo recipient of a cadaveric renal graft develops bleeding gums and easy bruising.The immunosuppressive agent most responsible is:
a:azathioprine
b:cyclosporine
crednisone
d:antitymocyte globulin


a:azathioprine
with BM suppression


28. 33yo woman,G4P4 presents to the ER with abdominal pain.She has a history of asthma,tobacco and alcohol abuse&STD.She had a cholecystectomy 7mo ago and a tubal ligation after the birth of her 4th child.On exam the pain is primarily located in the right lower quadrant,it increases when a hand is quickly removed from the abdomen.The pt has a positive Rovsing sign.Next step of Mx?
A:abdominal xray
B:US
C:CBC
D:serum beta-HCG
Eelvic exam


You did not state when her last menstrual period occurred.It will be prudent to rule out an ectopic gestation and then a pelvic examination.If her last menstrual period is 4 weeks and beyond then you will need to have urine f