supplement with phenytoin

Q: Which of the following supplement should be prescribed with phenytoin?

A) Vtamin C
B) Vitamin B6
C) Vitamin B9
D) Vitamin B12
E) Vitamin D


Answer: C

Vitamin B9 is Folic acid!

Phenytoin causes folic acid depletion in the body. Folic acid is not stored in the body in large amounts, and blood levels get low very quickly, resulting in signs and symptoms of folate deficiency like gingival hypertrophy.

#pharmacology


Reference: 

Arya R, Gulati S, Kabra M, et al. Folic acid supplementation prevents phenytoin-induced gingival overgrowth in children. Neurology 2011; 76:1338.

“rapid atrial swirl sign“ (RASS)

Q: What is  “rapid atrial swirl sign“ (RASS)?

Answer: RASS is a quick bedside echocardiographic sign, which can be obtained using the same ultrasound machine used to place a central venous catheter (CVC) to determine the correct positioning of the CVC tip. It is obtained by injecting 10 mL of normal saline via the distal port of CVC and observing a bright flush (or rapid opacification) of/within the right atrium. Subclavian CVCs tend to travel upward in the retrograde direction, and this can provide a quick bedside confirmation.

#procedures



Reference: 

Korsten P, Mavropoulou E, Wienbeck S, et al. The “rapid atrial swirl sign” for assessing central venous catheters: Performance by medical residents after limited training. Rothenbühler M, ed. PLoS ONE. 2018;13(7):e0199345.

intrinsic Nitric Oxide and vital organs

Q;  iNO (intrinsic Nitric Oxide) increases the risk of which organ dysfunction?

A) Heart
B) Lung
C) Kidney
D) Spleen
E) Liver


Answer: C 

 iNO may increase the risk of kidney dysfunction, particularly in patients who are in ICU for a prolong period of time and requires it prolong use as in ARDS.

iNO actually is beneficial to heart as a right heart afterload reducer (choice A) and improves hypoxemia (choice B), though it failed to show any improvement in mortality so far.

iNO has no significant effect on liver or spleen enzymes (choice D and E). In fact, recently it's use has been advocated during liver transplantation. 3

#nephrology
#transplantation
#cardiology
#pulmonary
#pharmacology


References:

1. Ruan SY, Huang TM, Wu HY, et al. Inhaled nitric oxide therapy and risk of renal dysfunction: a systematic review and meta-analysis of randomized trials. Crit Care 2015; 19:137. 

2. Gebistorf F, Karam O, Wetterslev J, Afshari A. Inhaled nitric oxide for acute respiratory distress syndrome (ARDS) in children and adults. Cochrane Database Syst Rev 2016; :CD002787.

3. Fukazawa K, Lang JD. Role of nitric oxide in liver transplantation: Should it be routinely used? World Journal of Hepatology. 2016;8(34):1489-1496.

PH and cardiac function

Q: Increasing PH by infusion of bicarbonate (select one)

A) decreases the cardiac function
B) increases the cardiac function


Answer: A

One of the reason bicarbonate never find its place in "ACLS protocol" as it decreases the ionized calcium, and consequently decreases the cardiac function.

#acidbase
#cardiology


References:

Orchard CH, Kentish JC. Effects of changes of pH on the contractile function of cardiac muscle. Am J Physiol 1990; 258:C967.

Adjuvant treatments in sepsis

Q: All of the following have shown some adjuvant benefit in septic shock except?

A) Vitamin C 
B) Thiamine 
C) Hydrocortisone 
D) Ibuprofen 
E) Esmolol


Answer: D

High burden of sepsis mortality has constantly geared investigators to look into alternate and adjuvant treatments for septic shock. Over the last five decades, the laundry list of such treatment has grown so long that can't be described here. 

NSAIDs (Non-steroidal Anti Inflammatory Drugs) as the name suggests have generated a lot of interest due to anti-inflammatory properties, but they failed to show any benefit in septic shock. 1

Interestingly, short-acting beta blocker (Esmolol) has shown benefit, probably due to attenuate the deleterious effects of the sympathetic adrenergic response (choice E).2, 3

Debate on the use of stress dose steroid in septic shock is never-ending but literature tends to lean towards some benefit, particularly in septic shock state unresponsive to resuscitation and pressor (choice C). 5

Thiamine and Vitamin C are relatively new on the horizon but have shown benefit in combination with steroid (Choices A and B). 4, 5, 6

#sepsis
#hemodynamics



References:

1. Bernard GR, Wheeler AP, Russell JA, et al. The effects of ibuprofen on the physiology and survival of patients with sepsis. The Ibuprofen in Sepsis Study Group. N Engl J Med 1997; 336:912.

2. Morelli A, Ertmer C, Westphal M, et al. Effect of heart rate control with esmolol on hemodynamic and clinical outcomes in patients with septic shock: a randomized clinical trial. JAMA 2013; 310:1683. 

3. Liu P, Wu Q, Tang Y, et al. The influence of esmolol on septic shock and sepsis: A meta-analysis of randomized controlled studies. Am J Emerg Med 2018; 36:470.

4. Mallat J, Lemyze M, Thevenin D. Do not forget to give thiamine to your septic shock patient! Journal of Thoracic Disease. 2016;8(6):1062-1066. 

5. Marik PE, Khangoora V, Rivera R, et al. Hydrocortisone, Vitamin C, and Thiamine for the Treatment of Severe Sepsis and Septic Shock: A Retrospective Before-After Study. Chest 2017; 151:1229. 

6. Woolum JA, Abner EL, Kelly A, Thompson Bastin ML, Morris PE, Flannery AH. Effect of Thiamine Administration on Lactate Clearance and Mortality in Patients With Septic Shock. Crit Care Med. 2018 Jul 18. [Epub ahead of print]

Optimum PEEP in lobar pneumonia - Intrapulmonary shunt

Q: High Positive End Expiratory Pressure (PEEP) can make hypoxemia worse in lobar pneumonia? (select one)

A) True
B) False


Answer: A

The objective of the above question is to highlight the understanding of optimum PEEP, as well as to know the consequences of higher than a required PEEP. In lobar pathology of the lung, higher PEEP may compress the healthy alveoli due to their higher elasticity and adaptability, and so the intraalveolar capillaries. This results in the intrapulmonary shunting, diverting the blood to the diseased areas of the lung.

#pulmonary
#ventilators


Reference:

Hasan FM, Beller TA, Sobonya RE, et al. Effect of positive end-expiratory pressure and body position in unilateral lung injury. J Appl Physiol Respir Environ Exerc Physiol 1982; 52:147.

Ketamine dose

Q: Ketamine is now increasingly used in ICU. Dose should be calculated by? (select one)

A) Ideal body weight
B) Actual body weight


Answer: A

Ketamine is a good choice for use particularly in obese patients where analgesia and sedation effects are required without respiratory depression. Ketamine has a very good safety profile in obese patients, and an opioid sparing effect. But, care should be taken while prescribing the dose as it should be be calculated by patient's ideal body weight.

#pharmacology



Reference:

 Avi A Weinbroum. Role and Advantageousness of Ketamine in Obese and Non-Obese Patients: Peri-Interventional Considerations. J Anesth Clin Res 9: 827, 2018

'rule of thumb' to transfuse one unit of FFP

Q: What is the 'rule of thumb' to infuse one unit of Fresh Frozen Plasma (FFP)?


Answer: 

In patients with no documented cardiac dysfunction, one unit of FFP can be given over 1.5 hours. And, if there is a concern for volume overload, it should be given slowly over four hours.

To put  exactly in terms of calculated value: healthy patients should be transfused with 2 to 3 mL/kg/hour, and cardiac failure patients with 1 mL/kg/hour.

#hematology


References:

Chowdary P, Saayman AG, Paulus U, et al. Efficacy of standard dose and 30 ml/kg fresh frozen plasma in correcting laboratory parameters of haemostasis in critically ill patients. Br J Haematol 2004; 125:69.

Median time period for IRIS after ART therapy

Q: What is the median time period for the development of Immune reconstitution inflammatory syndrome (IRIS) after the initiation of Anti Retroviral Therapy (ART) in AIDS-related opportunistic infections? 


Answer: 

The median time period for the development of Immune reconstitution inflammatory syndrome (IRIS) after the initiation of Anti Retroviral Therapy (ART) is about 33 days. It can occur anywhere between 2 to 8 weeks.

#infectiousdisease


Reference:

Grant PM, Komarow L, Andersen J, et al. Risk factor analyses for immune reconstitution inflammatory syndrome in a randomized study of early vs. deferred ART during an opportunistic infection. PLoS One 2010; 5:e11416.

Fat Embolism and Fat Embolism Syndrome

Q: What is the difference between fat embolism (FE) and fat embolism syndrome (FES)?


Answer: FE and FES are technically two related but different entities. FE is the presence of fat globules in the pulmonary circulation. In contrast, fat embolism syndrome (FES) is pulmonary and systemic symptoms due to the release of the fat particle into the circulation. Pathophysiology of FE is mostly mechanical and occurs within hours of the insult. FES is probably an extension or complication of FE and is more biochemical in nature. It may occur as a late manifestation of FE up to three days, can be more fatal, hard to manage and it is due to the release of free fatty acid, cytokines C-reactive protein in the blood.

#pulmonary
#ortho
#trauma
#shock



References: 

1. Stein PD, Yaekoub AY, Matta F, Kleerekoper M. Fat embolism syndrome. Am J Med Sci 2008; 336:472. 

2. Mellor A, Soni N. Fat embolism. Anaesthesia 2001; 56:145.

3. Nixon JR, Brock-Utne JG. Free fatty acid and arterial oxygen changes following major injury: a correlation between hypoxemia and increased free fatty acid levels. J Trauma 1978; 18:23. 

4.  Kao SJ, Yeh DY, Chen HI. Clinical and pathological features of fat embolism with acute respiratory distress syndrome. Clin Sci (Lond) 2007; 113:279. 

5. Prakash S, Sen RK, Tripathy SK, et al. Role of interleukin-6 as an early marker of fat embolism syndrome: a clinical study. Clin Orthop Relat Res 2013; 471:2340.

Blood cultures volume

Q: What is the optimal volume for each blood culture in adults? 

A) 5 mL 
B) 10 mL 
C) 20 mL 
D) 30 mL 
E) It does not depend on volume


Answer: C

The optimal volume for each blood culture in adults is 20 mL with 10 mL for an aerobic bottle and 10 mL for an anaerobic bottle, each.

Ideally three blood culture sets are recommended with first two blood cultures, drawn with separate venipunctures. The third blood culture set should be drawn four to six hours later.

The take home message of this question is to understand that low quantity of blood volume may hamper the results of blood culture (choice E).


#infectiousdiseases



References:

1. . Miller JM, Binnicker MJ, Campbell S, et al. A Guide to Utilization of the Microbiology Laboratory for Diagnosis of Infectious Diseases: 2018 Update by the Infectious Diseases Society of America and the American Society for Microbiology. Clin Infect Dis 2018. 

2.  Ilstrup DM, Washington JA 2nd. The importance of volume of blood cultured in the detection of bacteremia and fungemia. Diagn Microbiol Infect Dis 1983; 1:107. 

3. Mermel LA, Maki DG. Detection of bacteremia in adults: consequences of culturing an inadequate volume of blood. Ann Intern Med 1993; 119:270.

POUR

Q: Urinary bladder distension in ICU may cause? (select one)

A) Tachycardia
B) Bradycardia
C) Both (either)


Answer:   C 

With pain of bladder distension tachycardia is expected but any visceral distention like that of bowels or urinary bladder may cause a symptomatic bradycardia due to vagal reflex. 

Typically known as POUR (postoperative urinary retention), is usually a transient phenomenon but may stay for a significant period of time to cause hemodynamic instability. age, gender (male), drugs, type of anesthesia, underlying neurologic diseases are well-known risk factors. Beside urologic or bowel surgery, it may be of interest to know that joint arthroplasty is another risk factor. One time bladder catheterization (straight cath) should be performed if bladder scan determines >600 mL of urine. 

#surgicalcriticalcare
#urology



 Reference: 

Baldini G, Bagry H, Aprikian A, Carli F. Postoperative urinary retention: anesthetic and perioperative considerations. Anesthesiology 2009; 110:1139.

4 to 5 minutes rule of maternal code blue

Q: If a pregnant patient has a cardiac arrest and the uterine fundus is noted to be at or above the umbilicus, perimortem cesarean should be initiated at?

A) Two minutes
B) Four minutes
C) Eight minutes
D) Fifteen minutes
E) Only if there is an unsuccessful code 



Answer: B

If a pregnant patient has a cardiac arrest, it should be announced as "maternal code blue" so the obstetrical and neonatology teams can arrive at the initiation of code and can start preparing for cesarean delivery. It is recommended to have a person with a dedicated timer, and the procedure should begin at four minutes if ACLS protocol stays unsuccessful and the baby should be delivered by the end of the five minutes.

 During ACLS of a pregnant patient, if the uterus is at or above the umbilicus, it should be manually displaced to the left lateral position, while CPR is performed. Another important aspect to remember is to place intravenous (IV) access above the diaphragm. 

Actually, early delivery is associated with a successful outcome of the resuscitation process itself.

#ob-gyn
#cardiology


References:

1. Rose CH, Faksh A, Traynor KD, et al. Challenging the 4- to 5-minute rule: from perimortem cesarean to resuscitative hysterotomy. Am J Obstet Gynecol 2015; 213:653.

2. Doan-Wiggins L. Resuscitation of the pregnant patient suffering death. In: Cardiac Arrest: the science and practice of resuscitation medicine, Turrentine MA, Braems G, Ramirez MM (Eds), Williams and Wilkins, Philadelphia 1997. p.812.

prediction of resolution of constrictive pericarditis

Q: Resolution of constrictive pericarditis can be predicted even before any treatment is given? (select one)

A) True
B) False


Answer: A (True)

With the advent of Cardiac Magnetic Resonance (CMR), resolution of the constrictive pericarditis can be predicted even before any anti-inflammatory treatment is given. It can be predicted by the degree of late gadolinium enhancement (LGE) of the pericardium. Patients with tendency to have transient constrictive pericarditis have greater baseline LGE pericardial thickness and greater LGE qualitative intensity. LGE with pericardial thickness ≥3 mm predicted reversibility of constriction with 86 percent sensitivity and 80 percent specificity.

#cardiology
#radiology



Reference:

Feng D, Glockner J, Kim K, et al. Cardiac magnetic resonance imaging pericardial late gadolinium enhancement and elevated inflammatory markers can predict the reversibility of constrictive pericarditis after antiinflammatory medical therapy: a pilot study. Circulation 2011; 124:1830.

diabetic thoracic radiculopathy

Q: 58 year old male with a past medical history (PMH) of hypertension (HTN), Diabetes Mellitus (DM), Chronic Kidney Disease (CKD)-3 and coronary artery disease (CAD) with previous stents is admitted to ICU with chest pain. EKG seems unchanged from previous. First two troponins are negative. The patient described his chest pain different from previous as more sharp and burning. On examination, the patient found to have abdominal wall herniation. The patient will probably respond best to?

A) Nitroglycerine infusion
B) IV morphine
C) Gabapentin
D) Nonsteroidal Anti-inflammatory Drugs (NSAIDs)
E) Physical Therapy


Answer: C

Patient has diabetic thoracic radiculopathy, which can be very confusing in patients with poorly controlled diabetes and other underlying diseases. Chest pain is usually described differently as severe, sharp, and/or burning type. Many patients may develop abdominal muscle weakness and herniation. Fortunately, it is easy to treat and respond very well to gabapentin (dose up to 1200 mg three times daily). Non-responders may respond to 100 mg daily dose of nortriptyline or a course of  60 mg daily (divided) dose of oral prednisone.

Choice D is contra-indicated in this patient with underlying kidney disease. Physical therapy may help but it is not the first line of treatment. Nitroglycerine and morphine are not required as this is not the chest pain of cardiac origin.


#endocrinology
#neurology
#musculoskeletal


Reference:

Sun SF, Streib EW. Diabetic thoracoabdominal neuropathy: clinical and electrodiagnostic features. Ann Neurol 1981; 9:75. Chaudhuri KR, Wren DR, Werring D, Watkins PJ. Unilateral abdominal muscle herniation with pain: a distinctive variant of diabetic radiculopathy. Diabet Med 1997; 14:803.

Purtscher retinopathy

Q: What is Purtscher retinopathy? 


Answer: 

Purtscher retinopathy is a sudden decreased vision due to superficial retinal hemorrhages or cotton wool spots encircling the optic nerve. It can occur without any direct injury to the eye and can be seen in various diseases encountered in a critical care setting (see a long list of references below) like traumatic compression of the legs, chest or head, acute pancreatitis, amniotic fluid embolization, preeclampsia, HELLP syndrome and lupus. The exact mechanism is not clear but it appears to be leukoembolization, arterial occlusion, and infarction of the retinal microvascular bed, either due to fat embolization or leukocyte aggregation induced by complement C5a.

#opthalmology
#trauma
#vasculitis
#gastroenterology
#ob-gyn



References:

1. Agrawal A, McKibbin MA. Purtscher's and Purtscher-like retinopathies: a review. Surv Ophthalmol. 2006 Mar-Apr. 51(2):129-36.

2. Bhan K, Ashiq A, Aralikatti A, Menon KV, McKibbin M. The incidence of Purtscher retinopathy in acute pancreatitis. Br J Ophthalmol. 2008 Jan. 92(1):151-3. 

3. Sauer A, Nasica X, Zorn F, Petitjean P, Bader P, Speeg-Schatz C, et al. Cryoglobulinemia revealed by a Purtscher-like retinopathy. Clin Ophthalmol. 2007 Dec. 1 (4):555-7. 

4. Okwuosa TM, Lee EW, Starosta M, Chohan S, Volkov S, Flicker M, et al. Purtscher-like retinopathy in a patient with adult-onset Still's disease and concurrent thrombotic thrombocytopenic purpura. Arthritis Rheum. 2007 Feb 15. 57 (1):182-5

5. Dyrda A, Matheu Fabra A, Aronés Santivañez JR, Blanch Rubio J, Alarcón Valero I. Purtscher-like retinopathy as an initial presentation of iron-deficiency anaemia. Can J Ophthalmol. 2015 Feb. 50 (1):e1-2.

6. Landes A, Jay WM. Purtscher-like retinopathy in a patient with preeclampsia. Seminars in Ophthalmology. 2009. 24:217-220. 

7. Blodi BA, Johnson MW, Gass JD, Fine SL, Joffe LM. Purtscher's-like retinopathy after childbirth. Ophthalmology. 1990 Dec. 97(12):1654-9. 

8. Stewart MW, Brazis PW, Guier CP, Thota SH, Wilson SD. Purtscher-like retinopathy in a patient with HELLP syndrome. Am J Ophthalmol. 2007 May. 143(5):886-7. 

9. Chandra P, Azad R, Pal N, Sharma Y, Chhabra MS. Valsalva and Purtscher's retinopathy with optic neuropathy in compressive thoracic injury. Eye. 2005 Aug. 19(8):914-5. 

10. Chang M, Herbert WN. Retinal arteriolar occlusions following amniotic fluid embolism. Ophthalmology. 1984 Dec. 91(12):1634-7. 

11. Cooper BA, Shah GK, Grand MG. Purtscher's-like retinopathy in a patient with systemic lupus erythematosus. Ophthalmic Surg Lasers Imaging. 2004 Sep-Oct. 35(5):438-9.

12. Shah GK, Penne R, Grand MG. Purtscher's retinopathy secondary to airbag injury. Retina. 2001. 21(1):68-9. 

Bilirubinuria

Q: Bilirubinuria (bilirubin in the urine) reflects? (select one) 

 A) Conjugated bilirubinemia 
B) Unconjugated bilirubinemia


Answer: A

Unconjugated bilirubin is tightly bound to albumin and is not present in the urine. Presence of bilirubin in the urine indicates conjugated bilirubinemia and probable hepatobiliary disease process. 

Clinical significance: Bilirubinuria can exist with normal serum  conjugated bilirubin as reabsorptive capacity of kidney for conjugated bilirubin is low, and it can be an early sign of liver disease.

#hepatology

Reference: 

KLATSKIN G, BUNGARDS L. An improved test for bilirubin in urine. N Engl J Med 1953; 248:712.

"afterdrop"

Q: What is "afterdrop" during cardiopulmonary bypass (CPB)?



Answer: 

Most patients drop their core temperature after rewarming from hypothermic CPB and is known as "afterdrop".

It can be avoided by adequate rewarming before separation from CPB, and other measures such as increasing the room temperature, warming blood products and IV fluids and the use of a humidifier in ventilators. Hypothermia can have its own consequences with coagulopathy and platelet dysfunction.

#surgicalcriticalcare


References: 

Tindall MJ, Peletier MA, Severens NM, et al. Understanding post-operative temperature drop in cardiac surgery: a mathematical model. Math Med Biol 2008; 25:323.

Myxedema Coma

Q: All of the following are the signs and symptoms of myxedema coma except?

A) Hypernatremia 
B) Hypothermia 
C) Hypoventilation 
D) Hypoglycemia
E) Bradycardia


Answer: A

Myxedema coma causes hyponatremia in most of the patients. This is due to impairment of free water excretion due to inappropriate excess vasopressin secretion. Also impaired renal function and adrenal insufficiency plays a part. Treatment is to reverse hypothyroidism with thyroid replacement supported with steroid with mineralocorticoid activity. Simple mnemonic to remember treatment regimen of myxedema coma is 

R = Rewarming 
I = Isotonic Saline
T = Thyroid replacement
S = Steroid 


#endocrinology
#electrolytes




References:

1. Iwasaki Y, Oiso Y, Yamauchi K, et al. Osmoregulation of plasma vasopressin in myxedema. J Clin Endocrinol Metab 1990; 70:534. 

2.  Popoveniuc G, Chandra T, Sud A, et al. A diagnostic scoring system for myxedema coma. Endocr Pract 2014; 20:808.

3. Jonklaas J, Bianco AC, Bauer AJ, et al. Guidelines for the treatment of hypothyroidism: prepared by the american thyroid association task force on thyroid hormone replacement. Thyroid 2014; 24:1670.

Thrombosis in nephrotic syndrome

Q: 28 year old female with established diagnosis of nephrotic syndrome admitted to ICU with shortness of breath (SOB) and diagnosis of pulmonary embolism (PE). Work up showed hypoalbuminemia and renal vein thrombosis (RVT). What is the risk correlation between hypoalbuminemia and RVT?


Answer:  

The risk for arterial thrombosis, deep vein thrombosis (DVT) and renal vein thrombosis (RVT) gets proportionally high with the severity of the hypoalbuminemia. Once the serum albumin concentration is ≤2.8 g/dL, the risk starts to rise with a 2.13-fold increase for every 1 g/dL decrease in albumin below this level. 

Treatment consist as of any other acute thrombosis depending on the severity including anticoagulation, systemic or catheter based thrombolytic therapy or thrombectomy, followed by maintenance of warfarin therapy with INR goal of 2-3.

#nephrology
#hematology



Reference:

1. Lionaki S, Derebail VK, Hogan SL, et al. Venous thromboembolism in patients with membranous nephropathy. Clin J Am Soc Nephrol 2012; 7:43.

2. Weger N, Stawicki SP, Roll G, et al. Bilateral renal vein thrombosis secondary to membraneous glomerulonephritis: successful treatment with thrombolytic therapy. Ann Vasc Surg 2006; 20:411.


3. Dupree LH, Reddy P. Use of rivaroxaban in a patient with history of nephrotic syndrome and hypercoagulability. Ann Pharmacother 2014; 48:1655.

Blood warmer in blood product transfusions

Q: Use of blood warmer is preferred during transfusion of all of the following blood products except? (select one)

A) RBC units 
B) Plasma products 
C) Cryoprecipitate 
D) Platelets 
E) C & D


Answer: E

Use of blood warmer is highly recommonded during transfusion of cold and previously thawed blood products including pRBC and fresh frozen plasma (FFP). Transfusion without blood warmer may induce clinically significant hypothermia causing coagulopathy. Cryoprecipitate is required to be thawed to room temperature and does not requires blood warmer (choice C). Also, platelets are stored at room temperature and use of blood warmer is not necessary (choice D) 2.

#hematology



References: 

1. Madrid E, Urrútia G, Roqué i Figuls M, et al. Active body surface warming systems for preventing complications caused by inadvertent perioperative hypothermia in adults. Cochrane Database Syst Rev 2016; 4:CD009016.

2. Konig G, Yazer MH, Waters JH. Stored platelet functionality is not decreased after warming with a fluid warmer. Anesth Analg 2013; 117:575.

Bactrim in patients with Cystic Fibrosis

Q: The dose of oral trimethoprim-sulfamethoxazole (Bactrim) in patients with Cystic Fibrosis (CF) should be adjusted to? (select one) 

 A) Increase the dose 
B) Decrease the dose 


Answer: A

The dose of oral trimethoprim-sulfamethoxazole in patients with Cystic fibrosis need to be increased by almost 50 percent. This is due to the fact that hepatic clearance of sulfamethoxazole is increased in these patients due to accelerated acetylation. Also, clearance of trimethoprim via kidney gets enhanced. The reason for this renal effect is not clear.

#pharmacology



Reference:

Reed MD, Stern RC, Bertino JS Jr, et al. Dosing implications of rapid elimination of trimethoprim-sulfamethoxazole in patients with cystic fibrosis. J Pediatr 1984; 104:303.

Malignant Hyperthermia and Neuroleptic malignant syndrome

Q: Which of the following statement(s) is/are true? (Select one)

A) Malignant Hyperthermia (MH) in the postoperative period is extremely rare
B) Neuroleptic malignant syndrome (NMS) is usually of slow onset
C) Usually, clinical signs of MH occurs within one hour of anesthesia induction
D) NMS usually does not occur during administration of general anesthesia
E) All of the above


Answer: E

The objective of the above question is to highlight the major differentiating point between MH and NMS in view of their timings. MH is extremely rare in the postoperative period. Although it usually occurs within one hour of anesthesia induction but can occur any time during anesthesia due to triggering agent. In contrast, NMS may take up to 72 hours to clearly manifest and practically never occurs during administration of general anesthesia.

#pharmacology
#surgicalcriticalcare



References:

1. Velamoor VR, Norman RM, Caroff SN, et al. Progression of symptoms in neuroleptic malignant syndrome. J Nerv Ment Dis 1994; 182:168.

2.  Larach MG, Gronert GA, Allen GC, et al. Clinical presentation, treatment, and complications of malignant hyperthermia in North America from 1987 to 2006. Anesth Analg 2010; 110:498.

CXR pearl

Q: Equalization of blood vessels on CXR ( upper and basal vessels are equally dilated) occurs in all of the following except? 

A) left ventricular failure 
B) left-to-right shunts 
C) hyperthyroidism 
D) pregnancy 
E) anemia 


 Answer:  A

Meticulous reading of chest-X-ray (CXR) can provide valuable information on underlying disease. "Cephalization" on CXR means the upper lobe vessels are more dilated than the basal vessels is the hallmark of the diseases like left ventricular failure, mitral valve stenosis, basal emphysema or patients lying in recumbent patients. 

Similarly equalization or balanced flow is seen in hyperdynamic circulation as left-to-right shunts, hyperthyroidism, pregnancy, or anemia. 

#radiology
#pulmonary


Reference:

Ravin CE. Pulmonary vascularity: radiographic considerations. J Thorac Imaging 1988; 3:1.

Pupillary reflexes in NMBAs

Q: Which of the following Neuro-muscular blocking agent (NMBA) is unreliable in determining pupillary reflexes in ICU?

A) Cisatracurium
B) Pancuronium
C) Vecuronium
D) Succinylcholine
E) Rocuronium


Answer:  B

Patients who require NMBA use in ICU should be examined frequently for any change in neurological changes. The quick, reliable and easy way is to look for pupillary reactions. Although Pancuronium is not much of use in ICU due to its long recovery time, impaired metabolism in renal as well as hepatic dysfunction and significant accumulation, it may still be used in patients who require very long neuromuscular blocking as in severe ARDS.

Most of the NMBAs do not interfere with pupillary reflexes except for pancuronium due to its antimuscarinic effects.


#pharmacology


Reference:

Pancuronium bromide Injection [prescribing information]. Lake Forest, IL: Hospira, Inc; September 2010.

Remifentanil for mechanically ventilated patients

Q: Remifentanil has been advocated for use in mechanically ventilated patients for analgesia. What are the three main characteristics of this drug which make it superior to other continuous analgesia infusions in ICU? 


Answer: 

Remifentanil has been advocated for off-label use in ICU for mechanically ventilated patients 1 as a continuous infusion over fentanyl or morphine because of it's few characteristics which include.

1. ultrashort duration of action with the onset of action in 1-3 minutes, peak effect in 3-5 minutes and total duration of up to 10 minutes.

2. In patients with severe multiorgan failure, it has an advantage as its effect does not depend on renal or hepatic metabolism.

3. In patients with hemodynamic instability or bronchospasm, it has the advantage to release little histamine.

But, it should be used with caution in awake patients as may cause respiratory depression, and in patients with bradycardia. Also, if used with serotonergic agents, it may cause Serotonin syndrome. Also, it can elevate the intra-cranial pressure. 4


#pharmacology



References:

1. Dahaba AA, Grabner T, Rehak PH, et al. Remifentanil versus morphine analgesia and sedation for mechanically ventilated critically ill patients: a randomized double blind study. Anesthesiology 2004; 101:640.

2. Tan JA, Ho KM. Use of remifentanil as a sedative agent in critically ill adult patients: a meta-analysis. Anaesthesia 2009; 64:1342.

3.. Barr J, Fraser GL, Puntillo K, et al, “Clinical Practice Guidelines for the Management of Pain, Agitation, and Delirium in Adult Patients in the Intensive Care Unit,” Crit Care Med, 2013, 41(1):263-306.

4.  Warner DS, Hindman BJ, Todd MM, et al, “Intracranial Pressure and Hemodynamic Effects of Remifentanil Versus Alfentanil in Patients Undergoing Supratentorial Craniotomy,” Anesth Analg, 1996, 83(2):348-53. 

Functions of Ileum

Q: When surgery of intestine is considered, which important function(s) of ileum should be considered? 

A) Vitamin B12 absorption 
B) Bile acid absorption 
C) "Ileal brake" 
D) Fluid absorption 
E) All of the above


Answer: E

When the resection of the intestine become inevitable for various reasons, being an ICU physician it may be of importance to know some very important functions of ileum while parenteral or enteral nutrition is considered postoperatively.

Out of all of the above, probably the most important to know is that the distal 50 cm of the ileum is the primary site for vitamin B12 absorption, as resection of the terminal ileum is very common in short bowel syndrome (SBS). It requires lifelong vitamin B12 supplementation. 

Second most important to know that the distal ileum is the 'selective site' for bile acids absorption, and need close observation for malabsorption of fat as well as fat-soluble vitamins. Another secondary effect of non-absorption of bile acid is the colonic secretomotor diarrhea. 1

 "Ileal brake" is an interesting and a less known concept. Unabsorbed lipids reaching the ileum cause a delay in gastric emptying which can be beneficial if residual ileum can be spared during the surgery. 2,3

Ileum has an active salt transport which facilitates the reabsorption of the fluid secreted by the jejunum. Also, it helps in the absorption of fluid entering the gut via hypertonic feedings. 4

#nutrition
#surgicalcriticalcare



References:

1. Hofmann AF, Poley JR. Role of bile acid malabsorption in pathogenesis of diarrhea and steatorrhea in patients with ileal resection. I. Response to cholestyramine or replacement of dietary long chain triglyceride by medium chain triglyceride. Gastroenterology 1972; 62:918. 

2. Welch IM, Cunningham KM, Read NW. Regulation of gastric emptying by ileal nutrients in humans. Gastroenterology 1988; 94:401. 

3. Van Citters GW, Lin HC. Ileal brake: neuropeptidergic control of intestinal transit. Curr Gastroenterol Rep 2006; 8:367.

4. Fordtran JS, Rector FC Jr, Carter NW. The mechanisms of sodium absorption in the human small intestine. J Clin Invest 1968; 47:884.  

Propofol and PET scan

Q: Propofol should be discontinued in patients going for Positron Emission Tomography/Computed Tomography(PET) scan at least? (select one)

A) 48 hours prior
B) 24 hours prior
C) 6 hours prior
D) 30 minutes prior
E) It does not have any effect and can be continued 



Answer: D

Propofol interferes with fluorodeoxyglucose (FDG) uptake and should be discontinued at least 30 minutes prior to PET scan. Propofol depresses glucose disappearance from the blood stream without affecting plasma insulin secretion. This depression is induced by accumulating free fatty acid due to lipids in propofol infusion.

#pharmacology



Reference:

Zhongjin Y, Minji C, Ammar A, et al. (2017) Impact of Sevoflurane and Propofol Anesthesia on Quality of [18F] FDG-PET Scan Image. SOJ Anesthesiol Pain Manag. 4(2): 1-4.

Chlorhexidine bathing in ICUs

Q: Chlorhexidine bathing is superior to bathing with soap and water in ICUs? (select one)

A) True
B) False


Answer: A

Most of the studies have now established that bath/cleaning of patients with chlorhexidine-impregnated washcloths every day is superior to bathing with soap and water in ICUs. There are two major reasons behind it. First, it decreases the colonization of drug-resistant organisms. Second, (excess) water may be associated with an increased catheter exit-site infections. 4 Daily bathing with chlorhexidine also showed to decrease the line infections. 3

#infectiousdiseases



References:

1. O'Horo JC, Silva GL, Munoz-Price LS, Safdar N. The efficacy of daily bathing with chlorhexidine for reducing healthcare-associated bloodstream infections: a meta-analysis. Infect Control Hosp Epidemiol 2012; 33:257. 

2. Climo MW, Yokoe DS, Warren DK, et al. Effect of daily chlorhexidine bathing on hospital-acquired infection. N Engl J Med 2013; 368:533.

3. Montecalvo MA, McKenna D, Yarrish R, et al. Chlorhexidine bathing to reduce central venous catheter-associated bloodstream infection: impact and sustainability. Am J Med 2012; 125:505. 

4. Marchaim D, Taylor AR, Hayakawa K, et al. Hospital bath basins are frequently contaminated with multidrug-resistant human pathogens. Am J Infect Control 2012; 40:562. 

Fire during cardioversion

Q: All of the following are true regarding electrical cardioversion except?

A) Oxygen saturation should be monitored
B) Intravenous access should be established
C) Cart for  advanced cardiac life support (ACLS) should be made available
D) Should be performed only by a physician
E) Supplemental oxygen (nasal cannula/venti-mask) should be transiently removed during application of shock


Answer: D

The objective of the above question is to point out the hazard of fire during electrical cardioversion. Any open access of oxygen like nasal cannula or venti-mask should be held for those seconds when a shock is applied for electrical cardioversion, so choice E is correct! The risk is higher if oxygen saturation > 50% and within 30 cm of the patient. Pausing the ventilator for few seconds while shock is applied has been mentioned but there is no concrete evidence to support this practice as ventilators usually have a closed circuit.

Electrical cardioversion can be performed by any person trained including nurses and midlevel providers.

#cardiology


Reference: 

1. ECRI Institute. Hazard report: using external defibrillators in oxygen-enriched atmospheres can cause fires. Health Devices 2005; 34: 423-425. 

2. American Heart Association Guidelines for CPR and ECC, 2005. Supplement to Circulation. 2005;112:IV-41.

Munchausen syndrome

Q: Factitious disorder (Munchausen syndrome) is characterized by all of the following except? 

 A) Higher in female gender 
B) Higher in married individuals 
C) Higher in healthcare workers 
D) Excellent verbal skills 
E) Possible positive findings on CT/MRI (neuro-imaging)


Answer: B

Factitious disorder is a psychiatric disorder characterized by a patient deceptively misrepresent an illness and/or injury even there is no financial reward.

The objective of above question is to emphasis that although factitious disorder is considered as a pure non-physiological state but recent  reports are pointing towards positive findings in brain, like disseminated white matter lesions on MRI, bilateral frontotemporal cortical atrophy on CT scan or hyperperfusion of the right thalamus on SPECT scan.

It is more common in unmarried individuals.

#psychiatry 



References:

1. Bass C, Halligan P. Factitious disorders and malingering: challenges for clinical assessment and management. Lancet 2014; 383:1422.

2. Pankratz L, Lezak MD. Cerebral dysfunction in the Munchausen syndrome. Hillside J Clin Psychiatry 1987; 9:195. 

3. Fénelon G, Mahieux F, Roullet E, Guillard A. Munchausen's syndrome and abnormalities on magnetic resonance imaging of the brain. BMJ 1991; 302:996. 

4. Babe KS Jr, Peterson AM, Loosen PT, Geracioti TD Jr. The pathogenesis of Munchausen syndrome. A review and case report. Gen Hosp Psychiatry 1992; 14:273. 

5. Mountz JM, Parker PE, Liu HG, et al. Tc-99m HMPAO brain SPECT scanning in Munchausen syndrome. J Psychiatry Neurosci 1996; 21:49.