Q: How Therapeutic Hypothermia (TH) can be achieved by infusion of saline?


Answer: 

 Rapid intravenous bolus infusion of  Normal Saline (NS) with 30 mL/kg at 4°C (39°F), via pressure bag reduces the core temperature by more than 2°C per hour. Other "rule of thumb" method is to give a liter of cold saline (4°C 39°F) over 15 minutes. It drops the core temperature by approximately 1°C per hour. This method should be used with caution in patients with congestive heart failure (CHF) or renal insufficiency.


References:

1. Kim F, Olsufka M, Longstreth WT Jr, et al. Pilot randomized clinical trial of prehospital induction of mild hypothermia in out-of-hospital cardiac arrest patients with a rapid infusion of 4 degrees C normal saline. Circulation 2007; 115:3064. 

2. Kliegel A, Losert H, Sterz F, et al. Cold simple intravenous infusions preceding special endovascular cooling for faster induction of mild hypothermia after cardiac arrest--a feasibility study. Resuscitation 2005; 64:347.

Q: Which of the following antibiotic can cause nephrogenic diabetes insipidus

A) Demeclocycline (Tetracycline)
B) Cefepime
C) Vancomycin
D) Fluoroquinolone


Answer: A

Demeclocycline is known to cause a nephrogenic diabetes insipidus, This makes it a treatment option for the syndrome of inappropriate antidiuretic hormone secretion (SIADH). The mechanism of action is though to be the  reduce responsiveness of the collecting tubule cells to ADH. 

The history in this regard is interesting. This side effect was reported in 1975 and three years later, a study showed  it to be more effective and better tolerated than lithium carbonate, which was the only available treatment at the time.


References:


1. Cherrill DA, Stote RM, Birge JR, Singer I (November 1975). "Demeclocycline treatment in the syndrome of inappropriate antidiuretic hormone secretion". Annals of Internal Medicine. 83 (5): 654–6.

2. Goh KP (May 2004). "Management of hyponatremia". American Family Physician. 69 (10): 2387–94.

Q: 38 year old marathon runner stopped running and he appears confused, dazed and found to be unaware of his environment. Paramedics at the site seek your advise, as you offer your services being a doctor and a good Samaritan. Paramedics wants to infuse 100 cc of 3 percent normal saline (3% NS)

A) Agree with their decision
B) Disagree with their decision
C) Agree with their decision, only if sodium measurement is available
D) Advise them not to do anything till patient get evaluated in emergency room (ER)
E) Advise to give patient a bottle of gatorade to drink


Answer: A

Though it sounds odd to give 3% NS in field without any sodium level check but according to 2015 Third International Exercise-Associated Hyponatremia Consensus Development Conference, any athlete who clinically exhibits symptoms of  hyponatremic encephalopathy should be immediately treated with a 100 mL bolus of 3% NS, irrespective of sodium level availability. This makes sense as benefit of preventing permanent neural damage secondary to hyponatremia is higher than mild bump in sodium level. In fact, as per guidelines, if symptoms persist, 3% NS bolus can be repeated  two more times at ten minutes interval (with the hope that by this time sodium level would be available)! 3% NS should not be given if serum sodium has risen 3 to 7 meq/L above the initial value, or neurological symptom resolves.



References:

1. Hew-Butler T, Rosner MH, Fowkes-Godek S, et al. Statement of the Third International Exercise-Associated Hyponatremia Consensus Development Conference, Carlsbad, California, 2015. Clin J Sport Med 2015; 25:303. 

2.  Siegel AJ, Verbalis JG, Clement S, et al. Hyponatremia in marathon runners due to inappropriate arginine vasopressin secretion. Am J Med 2007; 120:461.e11. 

3.  Hew-Butler T, Anley C, Schwartz P, Noakes T. The treatment of symptomatic hyponatremia with hypertonic saline in an Ironman triathlete. Clin J Sport Med 2007; 17:68. 

4. Ayus JC, Arieff A, Moritz ML. Hyponatremia in marathon runners. N Engl J Med 2005; 353:427.

Q: What is the cut off point of D-Dimer to rule out Aortic dissection (AD)?


Answer: Below 500 ng/mL

D-dimer is a strong serum marker for acute dissection. Level below 500 ng/mL has a negative predictive value of 96 percent to rule out aortic dissection. But still it is not a standard in clinical practice, as AD has been reported in patients below 400 ng/mL.


References:


1. Suzuki T, Distante A, Zizza A, et al. Diagnosis of acute aortic dissection by D-dimer: the International Registry of Acute Aortic Dissection Substudy on Biomarkers (IRAD-Bio) experience. Circulation 2009; 119:2702. 

2. Shimony A, Filion KB, Mottillo S, et al. Meta-analysis of usefulness of d-dimer to diagnose acute aortic dissection. Am J Cardiol 2011; 107:1227. 

3. Paparella D, Malvindi PG, Scrascia G, et al. D-dimers are not always elevated in patients with acute aortic dissection. J Cardiovasc Med (Hagerstown) 2009; 10:212.

4. Asha SE, Miers JW. A Systematic Review and Meta-analysis of D-dimer as a Rule-out Test for Suspected Acute Aortic Dissection. Ann Emerg Med 2015; 66:368. 

5. Marill KA. Serum D-dimer is a sensitive test for the detection of acute aortic dissection: a pooled meta-analysis. J Emerg Med 2008; 34:367.

Q: All of the following required a monitored negative pressure room isolation except? 

A) Tuberculosis (TB)
B) Varicella 
C) Measles 
D) RSV 
E) Ebola


Answer: D

Airborne isolation requires a meticulous guidelines to follow. Patient should be placed in a monitored negative pressure room with at least 6 to 12 air exchanges per hour. Room exhaust must be appropriately discharged outdoors or passed through a HEPA filter before recirculation within the hospital. In case of TB, a certified respirator must be worn.

Objective of above question is to highlight less known infections which require negative pressure room like varicella, measles, and smallpox. 

On the other hand rubella, mumps, RSV and Influenza require droplet isolation.

Please refer to the link in reference, if needed to confirm type of isolation required


Reference:

Siegel JD, Rhinehart E, Jackson M, et al. Healthcare Infection Control Practices Advisory Committee 2007 Guideline for Isolation Precautions: Preventing Transmission of Infectious Agents in Healthcare Settings, June 2007. 

http://www.cdc.gov/hicpac/pdf/Isolation/Isolation2007.pdf

Q: Which of the following antibiotics is suitable for Internal Jugular (IJ) Central venous catheter (CVC) related suppurative thrombophlebitis?

A)  ampicillin-sulbactam 
B) piperacillin-tazobactam 
C) ticarcillin-clavulanate 
D) Addition of Vancomycin to any of the above antibiotics


Answer: D 

Jugular vein suppurative thrombophlebitis is popularly known as Lemierre's syndrome, postanginal sepsis, and necrobacillosis. Jugular vein suppurative thrombophlebitis is a life threatening infection. First and most importantly, foci of infection i.e. CVC should be removed. All of the antibiotics outlined in choices A, B and C are appropriate choices. But, in ICU or hospital setting vancomycin should be added to cover against skin flora.

Objective of above question is to emphasis the point that empiric therapy for jugular vein suppurative thrombophlebitis should include a beta-lactamase resistant beta-lactam antibiotic, along with vancomycin in hospital (or ICU) setting. Moreover, "lines" should be discontinued ASAP, if they are not needed. "Lines" should not be left for "just in case" reasons!


Reference:

Hagelskjaer Kristensen L, Prag J. Lemierre's syndrome and other disseminated Fusobacterium necrophorum infections in Denmark: a prospective epidemiological and clinical survey. Eur J Clin Microbiol Infect Dis 2008; 27:779.

Q: Acute obstruction of the upper (tracheal) airway is a life-threatening emergency. Patient may remain asymptomatic until the trachea is critically narrowed to

A) less than 40 mm
B) less than 30 mm
C) less than 20 mm
D) less than 10 mm
E) this cannot be quantify


Answer: D

Fortunately or unfortunately, patients may remain  asymptomatic until the trachea is critically narrowed to less than 10 mm. Clinically, this bears a very narrow margin of safety and call for bringing all available resources and backup at disposal.

Q: Which one caveat makes reading of lactic acidosis unreliable in ethylene glycol toxicity?


Answer: Many laboratory equipment cannot distinguish lactate from glycolate (a metabolite of ethylene glycol) as they both are structurally similar. It would be appropriate to make clear with lab personnel directly, and go with other parameters and clinical situation of  a patient.


Reference:

Pernet P, Bénéteau-Burnat B, Vaubourdolle M, et al. False elevation of blood lactate reveals ethylene glycol poisoning. Am J Emerg Med 2009; 27:132.e1.

Q: All of the following are the causes of unconjugated hyperbilirubinemia except?

A) Hemolysis
B) Heart failure
C) Portosystemic shunts
D) Hyperthyroidism
E) Total parenteral nutrition (TPN)


Answer: E

• Hemolysis causes increased production of bilirubin. 
• Heart failure and portosystemic shunts, tends to impair hepatic bilirubin uptake.
• Hyperthyroidism impairs bilirubin conjugation.

    - They all tend to cause unconjugated hyperbilirubinemia.

TPN causes intrahepatic cholestasis, and results in conjugated hyperbilirubinemia.

This information is very vital when patient is on TPN and cause of hyperbilirubinemia is sought.

Q: Therapeutically induced hypothermia should be considered in refractory convulsive status epilepticus along with intravenous infusion of other medications?

A) True
B) False


Answer: B

Once theoretically considered to be a good option of treatment, induced hypothermia failed to show any benefit in a recent clinical study (2016), when added to standard therapies for the initial treatment of convulsive status epilepticus.


Reference:

Legriel S, Lemiale V, Schenck M, et al. Hypothermia for Neuroprotection in Convulsive Status Epilepticus. N Engl J Med 2016; 375:2457.

Q: What is the mechanism behind Nonimmune (heparin-associated) thrombocytopenia?


Answer: In contrast to Heparin Induced Thrombocytopenia (HIT), a drop within the first two days of heparin exposure is not life threatening, though platelet count may drop down to 100,000/microL. 

This is due to platelet aggregation and no anti-platelet antibodies are produced.

It does not require discontinuation of heparin.

Q: Capnography waveform is consist of all of the following parts except?


A) Dead space ventilation 
B) Ascending inspiratory phase 
C) Alveolar Plateau 
D) End-tidal CO2 
E) Descending inspiratory phase


Answer: B

Capnography waveform is consist of following parts 

A) Dead space ventilation 
B) Ascending (upstroke) expiratory phase 
 C) Alveolar Plateau 
 D) End-tidal CO2 
 E) Descending (downstroke) inspiratory phase

Q: Why ice packs should be applied to the axillae, groin, and neck during Therapeutic Hypothermia (TH)?


Answer: 

The easiest way to achieve therapeutic hypothermia is to apply cooling blankets above and below the patient, and ice packs applied to the axillae, groin, and neck as they are adjacent to major blood vessels.

Q: Hyponatremia with a high or normal serum osmolality can occur in all of the following except?

A) ethanol ingestion
B) hyperglycemia
C) advanced renal failure
D) administration of hypertonic mannitol
E) in marathon  runners


Answer: E

Marathon and ultramarathon runners develop hyponatremia - not hypernatremia, contrary to popular belief (exercise-associated hyponatremia). It occurs due to excessive water intake combined, in many cases, with impaired water excretion due to persistent ADH secretion.

All other choices given (A, B, C and D) are associated with high or normal serum osmolality.



References:

1. Noakes TD, Sharwood K, Speedy D, et al. Three independent biological mechanisms cause exercise-associated hyponatremia: evidence from 2,135 weighed competitive athletic performances. Proc Natl Acad Sci U S A 2005; 102:18550. 

2. Almond CS, Shin AY, Fortescue EB, et al. Hyponatremia among runners in the Boston Marathon. N Engl J Med 2005; 352:1550. 

3. Sallis RE. Fluid balance and dysnatremias in athletes. Curr Sports Med Rep 2008; 7:S14.

Q: All of the following tetracyclines can be used in renal insufficiency except?

A) Doxycycline
B) Minocycline
C) Demeclocycline
D) Tigecycline


Answer: C

Out of all tetracyclines - Doxycycline, Minocycline and Tigecycline do not require any adjustment in renal dysfunction. Demeclocycline should be avoided in renal dysfunction.Demeclocycline inhibits the renal action of antidiuretic hormone, which may be used as an advantage in the syndrome of inappropriate antidiuretic hormone secretion (SIADH), but should be avoided for any other reasons, if renal insufficiency is present.

Q; Calorie dense formula contains

A) higher than usual free water as calories are dense
B) lower than required free water for patients' need
C) it doesn't contain any free water
D) Pharmacy adjust free water in each bag per patients' need


Answer: B

Calorically dense formulas contain as little as 60% free water, and may require supplementation of free water to avoid dehydration and electrolyte imbalance, particularly hypernatremia.

C is wrong answer as all formulas contain free water.

D is a wrong answer as enteral nutrition bags are prepackaged from commercial companies. And at least in US, hospital pharmacies don't prepare enteral formula for each patient, but they do prepare only Total Parenteral Nutrition (TPN), adjusting each patient need.

Q: After terminal discontinuation of ventilator support in patients destined for comfort care (withdrawal of care), all of the following effect the time to death except?

A) Number of organs not working
B) Vasopressor on board
C) Volume status
D) Surgical versus medical patient
E) Length of time on ventilator prior to extubation


Answer: E

As per study published in chest (2010), looking over 1500 patients, the median time to death after withdrawal of ventilator support was 0.9 hours. The major factors effecting the time to death included all of the above (Choices A, B, C and D) except the length of the time spent on ventilator prior to extubation.


Reference: 

Cooke CR, Hotchkin DL, Engelberg RA, et al. Predictors of time to death after terminal withdrawal of mechanical ventilation in the ICU. Chest 2010; 138:289.

ARTE Trial

ARTE (Aspirin Versus Aspirin + Clopidogrel Following TAVR) - DAPT vs SAPT

So far all patients who go through transcatheter aortic valve replacement (TAVR), receive dual-antiplatelet therapy (DAPT) per present guidelines, but here is the new development. ARTE trial were presented at the annual congress of the European Association of Percutaneous Cardiovascular Interventions by Dr. Josep Rodes-Cabau of Laval University in Quebec City.

ARTE was a multicenter, prospective, international open-label study of 222 TAVR patients who were randomized to 3 months of single-antiplatelet therapy (SAPT) with aspirin at 80-100 mg/day or to DAPT with aspirin at 80-100 mg/day plus clopidogrel at 75 mg/day after a single 300-mg loading dose.  Patients  had a mean Society of Thoracic Surgery Predicted Risk of Mortality score of 6.3%.

Results:

The primary outcome was the 3-month composite of

• death, 
• MI, 
• major or life-threatening bleeding, 
• stroke or transient ischemic attack. 

Results concluded 15.3% in the DAPT group and 7.2% in the SAPT group. Though study didn't achieve a statistical significance value (P = .065), probably  because of small sample size. But, importantly and most relevantly it showed strong and consistent benefit favoring SAPT,  in major or life-threatening bleeding achieved statistical significance.  Four bleeding events in the SAPT group were vascular in nature, while five of the 12 in the DAPT group were gastrointestinal. All the bleeding events in the SAPT group occurred within 72 hours after TAVR, whereas 5 of 12 in the DAPT recipients occurred later.

Only one patient on SAPT experienced life-threatening bleeding, compared with seven DAPT patients.

Important note: Trial was halted prematurely. The original study was planned to recruit 300 patients with over a year of follow-up. Trial was stopped due to slow enrollment and withdrawal of financial support by the study sponsors.


Reference:

Rodés-Cabau J and et al: - Aspirin Versus Aspirin Plus Clopidogrel as Antithrombotic Treatment Following Transcatheter Aortic Valve Replacement With a Balloon-Expandable Valve: The ARTE (Aspirin Versus Aspirin + Clopidogrel Following Transcatheter Aortic Valve Implantation) Randomized Clinical Trial.  .JACC Cardiovasc Interv. 2017 Jul 10;10(13):1357-1365. Epub 2017 May 17. 

Q: Which of the following has the highest chance of chemical cardioversion of atrial fibrillation

A) Ibutilide
B) Esmolol
C) Esmolol plus ibutilide
D) Digoxin


Answer: C

Esmolol plus ibutilide has shown higher chances of chemical conversion of recent-onset atrial fibrillation in comparison to ibutilide monotherapy alone. This is probably due to the fact that esmolol decreases the ventricular response. The slower the ventricular rate at the time of ibutilide administration, the greater is the probability of conversion to sinus rhythm. Moreover, combo therapy of esmolol and ibutilide  not only decreases the incidence of immediate atrial fibrillation recurrence but also the risk of torsade de pointes.

Digoxin has no direct role in chemical conversion of atrial fibrillation.


Reference:

Fragakis N, Bikias A, Delithanasis I, et al. Acute beta-adrenoceptor blockade improves efficacy of ibutilide in conversion of atrial fibrillation with a rapid ventricular rate. Europace 2009; 11:70.

Q; During Cardiopulmonary bypass (CPB) heparinization is considered to be adequate if target heparin concentration is

 A) More than or equal to 4 units/mL 
 B) More than or equal to 40 units/mL 
C) Less than 4 units/mL 
D) Heparin levels can't be measured by any means
E) Measuring heparin level is not standard, so activated clotting time (ACT) should be used


Answer: A

Though activated whole blood clotting time (ACT) between 400 to 480 seconds is considered to be adequate for heparinization during CPB, but another reliable method is to keep heparin concentration  more than or equal to 4 units/mL.

D is not true (we just made it up :)


Reference:

Finley A, Greenberg C. Review article: heparin sensitivity and resistance: management during cardiopulmonary bypass. Anesth Analg 2013; 116:1210.

Q: Glucocorticoids are used in thyroid storm for all of the following actions except? 

A) Reduce T4-to-T3 conversion
B) Promote vasomotor stability
C) Treat an associated relative adrenal insufficiency (if present)
D) Block new hormone synthesis


Answer: D

Thyroid storm requires multi-dimensional approach to manage different steps of thyroid synthesis, secretion, action and recirculation, like beta blocker controls the symptoms induced by increased adrenergic tone, a thionamide blocks the new hormone synthesis, an iodine solution blocks the release of thyroid hormone and an iodinated radiocontrast agent inhibits the peripheral conversion of T4 to T3. Some clinicians add bile acid sequestrants to decrease enterohepatic recycling of thyroid hormones.

Glucocorticoids reduces T4-to-T3 conversion, promote vasomotor stability, and treat an associated relative adrenal insufficiency, if present. It has no role in blocking new hormone synthesis.


Reference:

Ross DS, Burch HB, Cooper DS, et al. 2016 American Thyroid Association Guidelines for Diagnosis and Management of Hyperthyroidism and Other Causes of Thyrotoxicosis. Thyroid 2016; 26:1343.

Q: Magnesium sulfate should be infused with caution in which of the following patients

A) Myasthenia gravis
B) Asthma
C) Hypocalcemia
D) Hypokalemia
E) Torsade de pointes 


Answer:  A

Magnesium sulfate infusion should be used with caution in patients with myasthenia gravis since it can precipitate a severe myasthenia crisis. Magnesium is indicated in all other cases given in the question.



Reference:

Paramveer Singh, MD, Olakunle Idowu, MD, Imrana Malik, MD, and Joseph L. Nates, MD, MBA - Acute Respiratory Failure Induced by Magnesium Replacement in a 62-Year-Old Woman with Myasthenia Gravis - Tex Heart Inst J. 2015 Oct; 42(5): 495–497.

Q: Which method provides optimum way of suctioning in postoperative suction drainage bulbs , like Jackson-Pratt (JP) drain?  - Choose one

A)  by pressing the sides of the reservoir together 
B) by pushing the bottom of the reservoir toward the top



Answer: A

In suction based postoperative drains, compressing the sides of the reservoir is a far better technique for establishing negative pressure than pressing the bottom of the drain up toward the top.


Reference:

Carruthers KH, Eisemann BS, Lamp S, Kocak E. - Optimizing the closed suction surgical drainage system - Plast Surg Nurs. 2013 Jan-Mar;33(1):38-42;

Q: What's the easiest way ("rule of thumb") to calculate calories provided by standard tube feeding formulas in ICU? 


Answer: Most standard formulas in ICU provide 1 calorie per 1 milliliter (mL) and a nutrient composition quite similar to what is recommended for healthy individuals. 

Adjustment should be done looking at the label of the formula at bedside if caloric density formulas are on board. They are usually labelled as (formula name) 1.5. 

Q:  In vitro studies refers to experimentation in a controlled environment outside of a living organism. In vivo studies refers to experimentation inside or using a living organism. What does it means by in silico studies?


Answer: In silico refers to experimentations performed on computer or via computer simulation. Term is invented by a mathematician, Pedro Miramontes to characterize biological experiments carried out entirely in a computer. This aspect is can be used for identifying bacteria via in silico methods to sequence bacterial DNA and RNA. It is also used in polymerase chain reaction (PCR), generating millions or more copies of a particular DNA sequence.



References: 


1. Dantas, Gautam; Kuhlman, Brian; Callender, David; Wong, Michelle; Baker, David (2003), "A Large Scale Test of Computational Protein Design: Folding and Stability of Nine Completely Redesigned Globular Proteins", Journal of Molecular Biology, 332 (2): 449

2.  Dobson, N; Dantas, G; Baker, D; Varani, G (2006), "High-Resolution Structural Validation of the Computational Redesign of Human U1A Protein", Structure, 14 (5): 847

3. Dantas, G; Corrent, C; Reichow, S; Havranek, J; Eletr, Z; Isern, N; Kuhlman, B; Varani, G; et al. (2007), "High-resolution Structural and Thermodynamic Analysis of Extreme Stabilization of Human Procarboxypeptidase by Computational Protein Design", Journal of Molecular Biology, 366 (4): 1209–21

Q: After Staphylococcus spp, which of the following organism is the most common cause of infected (mycotic) arterial aneurysm?

A) Salmonella 
B) Treponema pallidum
C) Mycobacterium spp
D) Coxiella burnetii 
E) Candida



Answer: A

Staphylococcus spp and Salmonella spp, are so far the most common cause of mycotic aneurysm. Though list of organisms are long, but for reasons not fully understood Salmonella is easily prone to bacteremic seeding of atherosclerotic plaque.



References:

1. Brossier J, Lesprit P, Marzelle J, et al. New bacteriological patterns in primary infected aorto-iliac aneurysms: a single-centre experience. Eur J Vasc Endovasc Surg 2010; 40:582.

2. Hsu RB, Tsay YG, Wang SS, Chu SH. Surgical treatment for primary infected aneurysm of the descending thoracic aorta, abdominal aorta, and iliac arteries. J Vasc Surg 2002; 36:746.

3. Gomes MN, Choyke PL, Wallace RB. Infected aortic aneurysms: a changing entity. Ann Surg. 1992;215:435-442.

Q: Name few treatments for Post-lumbar puncture headache (PHPHA) if bed-rest and conventional analgesics don't work?


Answer: 

• Epidural blood patch 1
• Caffeine (oral or IV) 2,3
• IM adrenocorticotropic hormone (ACTH) 4
• IV hydrocortisone 5
• PO  theophylline 6
• SQ sumatriptan 7
• sphenopalatine block 8
• PO gabapentin 9
• Epidural saline 10

References:

1. Boonmak P, Boonmak S. Epidural blood patching for preventing and treating post-dural puncture headache. Cochrane Database Syst Rev 2010; :CD001791. 

2.  Camann WR, Murray RS, Mushlin PS, Lambert DH. Effects of oral caffeine on postdural puncture headache. A double-blind, placebo-controlled trial. Anesth Analg 1990; 70:181. 

3. Jarvis AP, Greenawalt JW, Fagraeus L. Intravenous caffeine for postdural puncture headache. Anesth Analg 1986; 65:316. 

4. Foster P. ACTH treatment for post-lumbar puncture headache. Br J Anaesth 1994; 73:429

5. Noyan Ashraf MA, Sadeghi A, Azarbakht Z, et al. Evaluation of intravenous hydrocortisone in reducing headache after spinal anesthesia: a double blind controlled clinical study [corrected]. Middle East J Anaesthesiol 2007; 19:415.

6. Feuerstein TJ, Zeides A. Theophylline relieves headache following lumbar puncture. Placebo-controlled, double-blind pilot study. Klin Wochenschr 1986; 64:216

7. Connelly NR, Parker RK, Rahimi A, Gibson CS. Sumatriptan in patients with postdural puncture headache. Headache 2000; 40:316. 

8. Kent S, Mehaffey G. Transnasal sphenopalatine ganglion block for the treatment of postdural puncture headache in the ED. Am J Emerg Med 2015; 33:1714.e1.

9. The effect of oral gabapentin on postdural puncture headache. Acute Pain 2006; 8:169.

10. RICE GG, DABBS CH. The use of peridural and subarachnoid injections of saline solution in the treatment of severe postspinal headache. Anesthesiology 1950; 11:17. 

Q: 64 year old male with End Stage Renal disease (on hemodialysis) presented to Emergency Room (ER) with chest pain and found to have unstable angina. Patient is known to cardiology service from previous 'cath' three months ago and was advised to go through bypass surgery but he opted for medical management. Now patient is agreeable for surgery. Review of his record showed that 3 months  ago while in hospital, he was tested positive for Heparin Induced Thrombocytopenia (HIT). His platelet counts are now normal, but to prepare him for surgery, his HIT panel was send again and found to be stayed positive. All of the following can be used in operation theater (OR) except?

A) preemptive  transfusion of platelets
B) Bivalirudin
C) Heparin reexposure but with intravenous Epoprostenol
D) Plasma exchange upon initiation of cardiopulmonary bypass (CPB)
E) Argatroban


Answer: A

Objective of above question is to highlight a less known option, epoprostenol. Epoprostenol is a prostaglandin PGI2 which can be used if heparin is used in a patient with positive HIT panel. Though bivalirudin or Argatroban can be used in this scenario but a surgeon may choose against them due to their inability to reverse the anticoagulant effect at the conclusion of cardiopulmonary bypass (CPB). Another viable option is plasma exchange upon initiation of CPB to reduce the titer of HIT antibodies prior to heparin exposure.

Epoprostenol potently desensitizes platelets during exposure to heparin by inhibiting platelet activation and by increasing intracellular concentrations of platelet cyclic adenosine monophosphate. It is given as an intravenous infusion while CPB runs and till protamine is administered to reverse heparin effect. Pharmacy service should be consulted for protocolized infusion of  epoprostenol. The most common side effect is vasoplegia.

Choices A is not a recommended option.



References:

1. Welsby IJ, Um J, Milano CA, et al. Plasmapheresis and heparin reexposure as a management strategy for cardiac surgical patients with heparin-induced thrombocytopenia. Anesth Analg 2010; 110:30.

2.  Koster A, Dyke CM, Aldea G, et al. Bivalirudin during cardiopulmonary bypass in patients with previous or acute heparin-induced thrombocytopenia and heparin antibodies: results of the CHOOSE-ON trial. Ann Thorac Surg 2007; 83:572.

3. Aouifi A, Blanc P, Piriou V, et al. Cardiac surgery with cardiopulmonary bypass in patients with type II heparin-induced thrombocytopenia. Ann Thorac Surg 2001; 71:678.

4. Mertzlufft F, Kuppe H, Koster A. Management of urgent high-risk cardiopulmonary bypass in patients with heparin-induced thrombocytopenia type II and coexisting disorders of renal function: use of heparin and epoprostenol combined with on-line monitoring of platelet function. J Cardiothorac Vasc Anesth 2000; 14:304. 

5. Warkentin TE, Greinacher A. Heparin-induced thrombocytopenia and cardiac surgery. Ann Thorac Surg 2003; 76:2121. 

6. Argatroban pharmacokinetics and pharmacodynamics in critically ill cardiac surgical patients with suspected heparin-induced thrombocytopenia. Thromb Haemost 2016; 115:1081.

4 Ds of increased obstetric mortality

Q; What are the 4 Delays (also called 4 Ds) of increased obstetric mortality?

Answer:

• Delay in decision
• Delay in transferring
• Delay in arranging (medical help)
• Delay in initiation (emergency treatment including IV Oxytocin, uterine massage and others)*

* Click here to see Obstetric Hemorrhage Checklist from The American College of Obstetricians and Gynecologists.

Q: What are the four Ts of Obstetric Hemorrhage?

Answer:

• Tone (i.e., atony) 
• Trauma (i.e., laceration) 
• Tissue (i.e., retained products) 
• Thrombin (i.e., coagulation dysfunction)

Q; What percentage of patients have neurological complications who require Extra Corporeal Membrane Oxygenation (ECMO) for pulmonary reason and cardiopulmonary reason respectively?


Answer:  As per  Extracorporeal Life Support Organization (ELSO) registry, the incidence of neurologic injury in adult respiratory failure (ARDS or ALI) patients is 10 percent but the incidence rise to 50 percent, if ECMO support is instituted  during cardiopulmonary resuscitation.

In pure pulmonary pathology, Veno-Venous (V-V ECMO) is required but in hemodynamic collapse Veno-Arterial (V-A ECMO) is required.


References: 

1. Brogan TV, Thiagarajan RR, Rycus PT, et al. Extracorporeal membrane oxygenation in adults with severe respiratory failure: a multi-center database. Intensive Care Med 2009; 35:2105.

2. Mateen FJ, Muralidharan R, Shinohara RT, et al. Neurological injury in adults treated with extracorporeal membrane oxygenation. Arch Neurol 2011; 68:1543.