Thursday, August 22, 2019

bicarb and lactate

Q: All of the following occurs with rapid intravenous bolus of sodium bicarbonate except

A) increase PCO2 
B) decrease production of lactate 
C) lower ionized calcium 
D) expand extracellular space 
E) raise the serum sodium concentration 


 Answer: B

This question is designed to point out the dangers associated with overuse of "bicarb" boluses in ICU. 


Sodium bicarbonate should be used very judiciously to raise PH only when it goes below 7.1.

An IV bolus of bicarbonate does exactly the opposite for which it is used! - it accelerates the production of lactate! 
Acidemia is a naturally occurring body protection. It acts as a "brake" on lactic acid generation by inhibiting glycolysis, largely mediated by a reduction in the activity of the enzyme, phosphofructokinase. Resolving acidemia too fast accelerates the production of lactate. 



#acid-base



Reference:


Hood VL, Tannen RL. Protection of acid-base balance by pH regulation of acid production. N Engl J Med 1998; 339:819.

Wednesday, August 21, 2019

CVC complication

Q: Ventricular dysrhythmias and bundle branch block can be avoided during central line (CVC) placement by keeping guide wire not going deeper than? 


 Answer: 16 cm

Studies have shown that Ventricular dysrhythmias and bundle branch block during CVC placement can be avoided by not going deeper than 16 cm of guide wire particularly from R side.


 #procedures



References:


1. Boyd R, Saxe A, Phillips E. Effect of patient position upon success in placing central venous catheters. Am J Surg 1996; 172:380. 

2. Lefrant JY, Muller L, De La Coussaye JE, et al. Risk factors of failure and immediate complication of subclavian vein catheterization in critically ill patients. Intensive Care Med 2002; 28:1036.

Tuesday, August 20, 2019

florinef

Q: Fludrocortisone works via?

A) increase in blood volume
B) enhanced sensitivity of blood vessels to circulating catecholamines 
C) enhanced norepinephrine release from sympathetic neurons
D) all of the above
E) none of the above


Answer: D

Fludrocortisone is a synthetic mineralocorticoid commonly used in ICU patients particularly with renal failure, and presumed renal insufficiency. Its mechanism of action is through various mechanisms including an increase in blood volume, enhanced sensitivity of blood vessels to circulating catecholamines, and enhanced norepinephrine release from sympathetic neurons.


#hemodynamics

#pharmacology




References:


1. Davies IB, Bannister RG, Sever PS, Wilcox CS. Fludrocortisone in the treatment of postural hypotension: altered sensitivity to pressor agents [proceedings]. Br J Clin Pharmacol 1978; 6:444P.

2. Chobanian AV, Volicer L, Tifft CP, et al. Mineralocorticoid-induced hypertension in patients with orthostatic hypotension. N Engl J Med 1979; 301:68.

Monday, August 19, 2019

NSAID induced peptic ulcer

Q: 32 year old athletic male is admitted to ICU with bleeding peptic ulcer due to overuse of Non-Steroidal-Anti-Inflammatory-Drugs (NSAIDs). Which of the following regimen would be most effective? 

A) Proton Pump Inhibitors (PPIs) 
B) Histamine 2- Receptor-Blockers (H2-R-B) 
C) Combine PPI and H2-R-blocker 
D) Sucralfate 
E) Milk of Magnesia (MoM)


Answer: A

NSAID-induced peptic ulcers are best treated with PPIs. Interestingly and surprisingly combine PPI and H2-R-B failed to show any synergistic or added advantage. Similarly, all other modalities were found inferior to PPI in the treatment of NSAID induced peptic ulcer.


#gastroenterology
#pharmacology



References:


Yeomans ND, Tulassay Z, Juhász L, et al. A comparison of omeprazole with ranitidine for ulcers associated with nonsteroidal antiinflammatory drugs. Acid Suppression Trial: Ranitidine versus Omeprazole for NSAID-associated Ulcer Treatment (ASTRONAUT) Study Group. N Engl J Med 1998; 338:719. 

Blum AL, Bethge H, Bode JC, et al. Sucralfate in the treatment and prevention of gastric ulcer: multicentre double blind placebo controlled study. Gut 1990; 31:825.

Sunday, August 18, 2019

SSRI effect of succinylcholine

Q: Selective serotonin reuptake inhibitors (SSRIs) tends to? (select one)

A) prolong the effect of succinylcholine
B) reduce the effect of succinylcholine


Answer: A

Succinylcholine is the most commonly used neuromuscular blockade (NMB) for intubation in ICU. A large number of patients admitted to ICU are now chronically on SSRIs. All SSRIs, in particular, fluoxetine and sertraline are inhibitors of cholinesterase in human serum and in the erythrocyte membrane. This tends to prolong the action for succinylcholine. 

#pharmacology
#procedures
#neurology


Reference:


Müller TC, Rocha JB, Morsch VM, et al. Antidepressants inhibit human acetylcholinesterase and butyrylcholinesterase activity. Biochim Biophys Acta 2002; 1587:92.

Saturday, August 17, 2019

ACS

Q: Early prophylactic fasciotomy is indicated in acute compartment syndrome (ACS) of an extremity if compartment pressure is within? 

A) 10 mmHg of diastolic pressure
B) 20 mmHg of diastolic pressure
C) 30 mmHg of diastolic pressure
D) 40 mmHg of diastolic pressure
E) 50 mmHg of diastolic pressure


Answer: C

In ICU, the most commonly used method to measure the compartment syndrome is through the arterial measure transducer and an 18G catheter inserted into the tissue compartment. This measurement is not accurate and should be read with clinical findings. The normal compartment pressure is between 0 and 8 mmHg, and ischemia starts to occur when the tissue pressure approaches diastolic pressure. Early prophylactic fasciotomy is indicated if ACS delta pressure (diastolic blood pressure ‒ measured compartment pressure) is less than 20 to 30 or if compartment pressure is within 30 mmHg of diastolic pressure.

The objective of this pearl is to highlight another compartment pressure measurement which may not be well known to ICU staff i.e, via manometer which is relatively more accurate. It is measured after injecting a small quantity of saline into a closed compartment and measuring the resistance through hand-held manometer. Simultaneously measuring Blood Pressure (BP) in non-effected extremity via manometer and compartment pressure via manometer may give a better perception of acuity to a clinician.


#trauma

#procedure


References:


1. Uliasz A, Ishida JT, Fleming JK, Yamamoto LG. Comparing the methods of measuring compartment pressures in acute compartment syndrome. Am J Emerg Med 2003; 21:143.

2. Dahn I, Lassen NA, Westling H. Blood flow in human muscles during external pressure or venous stasis. Clin Sci 1967; 32:467.

Friday, August 16, 2019

Fournier gangrene

Q: Fournier gangrene is more common in? (select one)

 A) male 
B) female


Answer: A

Necrotizing fasciitis of the perineum, popularly known as Fournier gangrene occurs due to a breach in the normal lining of the gastrointestinal (GI) or urethral mucosa. This may let a reader assume that this is more common amongst females but data suggests that it is more common in males. It quickly involves the anterior abdominal wall, gluteal muscles, scrotum, and the penile area.


#infectious-diseases



Reference: 


Ioannidis O, Kitsikosta L, Tatsis D, et al. Fournier's Gangrene: Lessons Learned from Multimodal and Multidisciplinary Management of Perineal Necrotizing Fasciitis. Front Surg. 2017;4:36. 

Thursday, August 15, 2019

UAG

Q: Which one is the right formula for Urine An-ion Gap (UAG)?

A) Urine (Na + K - Cl)
B) Urine (Na + HCO3 - Cl)
C) Urine (Na - K + Cl)
D) Urine (Na + K + Cl)
E) Urine (Na + K - HCO3)


Answer: A

The UAG is not a perfect science but it helps in determining the cause of metabolic acidosis.


The UAG gets calculated as the difference between the sum of the urine sodium (Na) plus potassium (K) concentrations and the urine chloride (Cl) concentration (choices C & D wrong).

 UAG = Urine (Na + K - Cl)

The formula for the UAG is different from the formula to calculate the serum anion gap. The serum anion gap is the difference between the serum sodium and the sum of the serum chloride and bicarbonate concentrations (choices B & E are wrong).

The quantity of sodium and potassium absorbed by the gastrointestinal tract usually exceeds the quantity of absorbed chloride. Thus,  the UAG usually has a positive value between 20 and 90. The best utility to measure UAG is in large volume and/or chronic watery diarrhea, where the loss of sodium and potassium occurs in the stool without a parallel fall in chloride excretion. This results in negative UAG.

 If UAG stays positive with a hyperchloremic or nonanion gap metabolic acidosis, it indicates low or normal NH4 excretion, such as a distal RTA.

#acid-base-balance
#nephrology
#gastroenterology



References:


1. Batlle DC, Hizon M, Cohen E, et al. The use of the urinary anion gap in the diagnosis of hyperchloremic metabolic acidosis. N Engl J Med 1988; 318:594. 

 2. Oh M, Carroll HJ. Value and determinants of urine anion gap. Nephron 2002; 90:252. 

 3. Kim GH, Han JS, Kim YS, et al. Evaluation of urine acidification by urine anion gap and urine osmolal gap in chronic metabolic acidosis. Am J Kidney Dis 1996; 27:42.

Wednesday, August 14, 2019

MALA

Q: Mortality from Metformin associated lactic acidosis (MALA), if occurs, is about?



Answer: 50%

Lactic acidosis from metformin, known as MALA is very rare. It is reported at the incidence of only about 4 cases per 100K patient-years. But if it occurs, mortality is around 45-50%. 


The biggest risk factor is the underlying comorbidity with liver, kidney, heart or alcohol abuse. There is no antidote for MALA but hemodialysis is considered the best treatment modality.


#toxicology

#pharmacology


References:


1. Salpeter SR, Greyber E, Pasternak GA, Salpeter EE. Risk of fatal and nonfatal lactic acidosis with metformin use in type 2 diabetes mellitus. Cochrane Database Syst Rev 2010; :CD002967.


2. Seidowsky A, Nseir S, Houdret N, Fourrier F. Metformin-associated lactic acidosis: a prognostic and therapeutic study. Crit Care Med 2009; 37:2191.

3. Calello DP, Liu KD, Wiegand TJ, et al. Extracorporeal Treatment for Metformin Poisoning: Systematic Review and Recommendations From the Extracorporeal Treatments in Poisoning Workgroup. Crit Care Med 2015; 43:1716.

Tuesday, August 13, 2019

TB test in HIV

Q: Below which CD4 count tuberculin skin test stays negative in HIV patients?


Answer: 300 cells/microL

Tuberculin skin test is still a useful test in HIV patients with positive read at >5 mm. Tuberculin test depends upon the CD4 count so the test become meaningless below 300 cells/microL.


#infectious-diseases



Reference:


1. https://www.cdc.gov/mmwr/preview/mmwrhtml/00031075.htm

Monday, August 12, 2019

Nimbex & hypothermia

Q: Hypothermia? (select one)

A) prolongs the effect of cisatracurium
B) shortens the effect of cisatracurium


Answer:  A

Hypothermia slows down the Hoffmann elimination process, resulting in prolonging the effect of cisatracurium.


#pharmacology

#neurology


Reference:


Kisor DF, Schmith VD. Clinical pharmacokinetics of cisatracurium besilate. Clin Pharmacokinet 1999; 36:27.

Sunday, August 11, 2019

Dose of Succinylcholine during intubation

Q: Dose of Succinylcholine during intubation should be based on? (select one) 

A) Ideal body weight 
B) Total body weight 


 Answer:

Succinylcholine is the most commonly used neuro-muscular blocker (NMB) in ICU for intubation. The recommended dose for intubation is 1.5 mg/kg intravenous (IV). It works within 60 seconds, and action lasts for 6 to 10 minutes. This dosage is based on total body weight. This becomes very important for proper intubation condition in obese as well as pregnant patients.



#procedure



References:


1. Naguib M, Samarkandi AH, El-Din ME, et al. The dose of succinylcholine required for excellent endotracheal intubating conditions. Anesth Analg 2006; 102:151. 


2. Lemmens HJ, Brodsky JB. The dose of succinylcholine in morbid obesity. Anesth Analg 2006; 102:438. 


3. Guay J, Grenier Y, Varin F. Clinical pharmacokinetics of neuromuscular relaxants in pregnancy. Clin Pharmacokinet 1998; 34:483. 



Saturday, August 10, 2019

HES

Q: How you define Hypereosinophilic syndromes (HES)? 

 
Answer: Absolute Eosinophilic Count ≥1500/microL on two occasions ≥1 month apart plus organ dysfunction attributable to eosinophilia. An important distinction to remember is if the clinical condition with hypereosinophilia can be explained by any other mechanism should not be labeled as HES. 

A complete description of this syndrome is beyond the scope of this pearl, but we strongly suggest to read this article:

Hypereosinophilic syndromes

Florence E Roufosse, Michel Goldman & Elie Cogan 

Orphanet Journal of Rare Diseases - volume 2, Article number: 37 (2007)


#immunology
#hematology


Reference: 

 Valent P, Klion AD, Horny HP, et al. Contemporary consensus proposal on criteria and classification of eosinophilic disorders and related syndromes. J Allergy Clin Immunol 2012; 130:607.

Friday, August 9, 2019

ketamine

Q: All of the following are possible effects of Ketamine except?

A) 'Out of body' experience
B) Amnesia 
C) Dilatation of pupils 
D) Increased muscle tone 
E) Absence-like effect


Answer:  CNS effects of Ketamine include a wide variety of symptoms. It includes agitation, dissociation, inability to sense pain, hallucination, ataxia, nystagmus. In abuse and with emergence reactions, patients may also experience extreme agitation, fear, and psychiatric disturbance. The typical presentation of ketamine abusers who present for medical evaluation is impaired consciousness, vivid dreams, "out of body" experiences, illusions, euphoria, and fear. It also causes amnesia, dilatation of pupils, increased muscle tone, and absence-like effect.

In severe overdose, ketamine may cause coma.


#neurology
#pharmacology


Reference:

Green SM, Li J. Ketamine in adults: what emergency physicians need to know about patient selection and emergence reactions. Acad Emerg Med 2000; 7:278.

Thursday, August 8, 2019

acyclovir

Q: Which drug is more prone to cause acute kidney dysfunction? (select one) 

 A) IV Acyclovir 
 B) IV Ganciclovir


 Answer:

 Acyclovir has low solubility and gets rapidly excreted in the urine. In a hypovolemic patient, deposition of acyclovir crystals in the tubules occurs quickly, causing an intratubular obstruction and interstitial inflammation. Ganciclovir does the same thing but with lesser intensity. Patients may complain of kidney stones like symptoms. The best prevention is IV hydration, adequate urine output @ 75 mL/hour and slow infusion of the drug.


#nephrology

#pharmacology


References:


Sawyer MH, Webb DE, Balow JE, Straus SE. Acyclovir-induced renal failure. Clinical course and histology. Am J Med 1988; 84:1067.

Wednesday, August 7, 2019

pain of biliary colic and acute cholecystitis

Q: How a pain of biliary colic and acute cholecystitis can be differentiated?


Answer:  Pain in biliary colic is described as dull discomfort but of high intensity. It usually stayed in the parameter of  Right Upper Quadrant (RUQ) or epigastrium and may be associated with nausea, vomiting, and diaphoresis. Most importantly, it lasts for 30 minutes, plateau within one hour, and other abdominal exam remains normal.

Pain in acute cholecystitis stays for more than 4 to 6 hours in RUQ or epigastric area and accompanied by fever. Associated abdominal exam shows guarding and positive Murphy's sign.

#physical-exam
#hepatology


Reference:

C. David Naylor. Physical Examination of the Liver. AMA. 1994;271(23):1859-1865

Tuesday, August 6, 2019

Auto PEEP

Q: Which one is correct for Auto-PEEP? (select one)

A) Auto-PEEP = end-expiratory alveolar pressure - applied PEEP

B) Auto-PEEP = end-inspiratory alveolar pressure - applied PEEP


Answer: A

Positive end-expiratory pressure is called PEEP. It is applied from the ventilator to avoid a complete collapse of alveoli at the end of the expiration. But less than the desired volume of expired air before the start of the next breath may result in air trapping and increases alveolar pressure at the end of expiration. This is called auto-PEEP. 
It can have life-threatening consequences if not addressed before time.

Auto-PEEP can be quantified at the bedside by applying a breath-hold at end-expiratory and calibrating the airway pressure while the ventilator stays at breath-hold. Taking off applied PEEP from this value gives the Auto-PEEP.


#ventilators

#pulmonary


Reference:


John J. Marini. Dynamic Hyperinflation and Auto–Positive End-Expiratory Pressure Lessons Learned over 30 Years. AJRCCM. Vol. 184, No. 7 | Oct 01, 2011

Monday, August 5, 2019

meningitis & encephalitis

Q: How the difference between encephalitis and meningitis can be established?

Answer: In patients with meningitis cerebral function remains normal though seizure may occur followed by post-ictal changes. In contrast, patients with encephalitis develop deficit with the brain function from altered mental status to the motor or sensory deficits (such as hemiparesis, flaccid paralysis or paresthesias). It may also include speech or movement disorders. Encephalitis may also present as behavior or personality changes. 

#neurology




Reference:


Matthew Short. Meningitis and encephalitis. Sage Journal. Volume: 9 issue: 10, page(s): 589-596

Sunday, August 4, 2019

HbA1C in surgery

Q: What level of Hb A1C is considered acceptable before surgery?


Answer: HbA1C < 8.5-9%

Elevated A1C levels and perioperative high blood sugar in diabetic patients may increase the risk of postoperative infectious and cardiovascular complications. In general Hb A1C > 8.5-9 % is considered at higher risk.


#endocrinology


References:

1. American Diabetes Association. 14. Diabetes Care in the Hospital. Diabetes Care 2017; 40:S120.


2. Membership of the Working Party, Barker P, Creasey PE, et al. Peri-operative management of the surgical patient with diabetes 2015: Association of Anaesthetists of Great Britain and Ireland. Anaesthesia 2015; 70:1427. 


3.Kao LS, Meeks D, Moyer VA, Lally KP. Peri-operative glycaemic control regimens for preventing surgical site infections in adults. Cochrane Database Syst Rev 2009; :CD006806. 

Saturday, August 3, 2019

Stridor

Q: Stridor due to laryngeal obstruction typically occurs with? (select one) 

A) inspiration
B) expiration



Answer: A

Stridor is due to the turbulent airflow in the partially obstructed upper airways and can be heard in various forms like wheezing, vibrating, musical, high-pitched or harsh. It most typically occurs with inspiration but can occur in expiration, or both. It is not granted but inspiratory stridor suggests a laryngeal obstruction. Tracheobronchial obstruction usually presents as expiratory stridor, and biphasic stridor suggests a subglottic or glottic obstruction. 


#ENT

#pulmonary


References:


1. Stridor in infants and children. Schoem SR, Darrow DH, eds. Pediatric Otolaryngology. Itasca, IL: American Academy of Pediatrics; 2012. 323-52.

2. Tan HKK, Holinger LD. How to evaluate and manage stridor in children. J Respir Dis. 1994. 15(3):245-260.

Friday, August 2, 2019

Ibutalide and TdeP

Q: All of the following are the risk factors for torsade de pointes (TdeP) after ibutilide administration except?  

A) Congestive heart failure 
B) Baseline increase QTc interval 
C) Hypokalemia 
D) Hypomagnesemia 
E) Associated atrial flutter




Answer: E

Ibutilide is found to be more effective in converting atrial flutter to sinus rhythm. All other are risk factors for TdeP while administrating Ibutilide. This risk can be minimized by administrating extra magnesium prior to ibutilide. It is recommended to watch closely and at least for four hours, for prolong QTc interval after Ibutilide is given.


#cardiology

#pharmacology



References:

1. Ellenbogen KA, Stambler BS, Wood MA, et al. Efficacy of intravenous ibutilide for rapid termination of atrial fibrillation and atrial flutter: a dose-response study. J Am Coll Cardiol 1996; 28:130. 


2. Patsilinakos S, Christou A, Kafkas N, et al. Effect of high doses of magnesium on converting ibutilide to a safe and more effective agent. Am J Cardiol 2010; 106:673.

Thursday, August 1, 2019

amylase/lipase in ETOH pancreatitis

Q: Which test is more reliable in acute alcoholic pancreatitis? (select one)

A) Amylase
B) Lipase



Answer: B

In non-alcoholic acute pancreatitis serum amylase usually rises more than three times the normal but chronic alcoholic patients may not be able to produce this elevation as their parenchyma lacks both in quality as well as in quantity. Also, amylase has a short half-life, less parenchyma for it's production and patients with ETOH abuse history tends to present more than 24 hours after the attack.


Serum lipase is specific to pancreas, has a longer half-life in days and requires less parenchyma to get produce.

#gastroenterology
#laboratory-medicine


References:

1. Yadav D, Agarwal N, Pitchumoni CS. A critical evaluation of laboratory tests in acute pancreatitis. Am J Gastroenterol 2002; 97:1309. 

2. Frank B, Gottlieb K. Amylase normal, lipase elevated: is it pancreatitis? A case series and review of the literature. Am J Gastroenterol 1999; 94:463. 

3. Treacy J, Williams A, Bais R, et al. Evaluation of amylase and lipase in the diagnosis of acute pancreatitis. ANZ J Surg 2001; 71:577.

Wednesday, July 31, 2019

Protamine

Q: Risk of side effects with protamine increases in all of the following patients except? 

 A) allergy to fish 
B) previous vasectomy 
C) severe left ventricular dysfunction 
 D) end stage renal disease (ESRD) 
E) abnormal pulmonary hemodynamics 


Answer: D

Side effects of protamine sulfate include hypotension, noncardiogenic pulmonary edema, severe pulmonary vasoconstriction, and pulmonary hypertension. Unfortunately there are many risk factors which are not easy to identify. Risk factors include rapid administration, previous administration of protamine-containing drugs like NPH insulin, and some beta-blockers, allergy to fish, previous vasectomy, and severe left ventricular dysfunction.


Renal or hepatic failure does not augment protamine reactions.


#pharmacology



Reference: 


Caravati EM. Protamine sulfate. Medical Toxicology. 3rd ed. Dart RC, ed. Philadelphia, PA: Lippincott Williams and Wilkins; 2004;243-244.

Tuesday, July 30, 2019

BUN;Cr ratio in GI bleed

Q: Patients with acute lower Gastro-intestinal (GI) bleeding with normal kidney function tends to have a normal blood urea nitrogen and creatinine (BUN:Cr) ratio? (select one)

A) True
B) False

Answer: A

Looking at BUN:Cr ratio is an excellent and quick method to differentiate between acute upper and lower GI bleed. Patients with acute lower GI bleeding and normal kidney function is very unlikely to have BUN:Cr ratio > 20:1.


#gastroenterology



Reference:


Mortensen PB, Nøhr M, Møller-Petersen JF, Balslev I. The diagnostic value of serum urea/creatinine ratio in distinguishing between upper and lower gastrointestinal bleeding. A prospective study. Dan Med Bull 1994; 41:237.

Monday, July 29, 2019

Language aura

Q: 33-year-old female is admitted to ICU with dysarthria and possible stroke. Neurology service made a diagnosis of crossed aura. What is crossed aura?


Answer: Crossed aura is associated with migraine and can be very deceiving. It is also known as language aura. In most people i.e. right-handed individuals, language is lateralized to the left hemisphere. If there is a lesion in the right cerebral hemisphere, it may manifest as wording difficulties, dysphasia or paraphasic errors.

#neurology



Reference:

Martins IP. Crossed aphasia during migraine aura: transcallosal spreading depression?. J Neurol Neurosurg Psychiatry. 2007;78(5):544–545. 


Sunday, July 28, 2019

ACS

Q: Extremity with acute compartment syndrome (ACS) should be? (select one)

A) Elevated to relieve pressure
B) Put in a dependent position
C) None of the above
D) Any of the above


Answer: C

Limb with ACS should not either be elevated or put in a dependent position. Elevating the extremity compromised the arterial inflow resulting in tissue hypoxia, and putting it in a dependent position exacerbates the compartment pressure.


#vascular

#surgical-critical-care


Reference:


Styf J, Wiger P. Abnormally increased intramuscular pressure in human legs: comparison of two experimental models. J Trauma 1998; 45:133.

Saturday, July 27, 2019

tracheoarterial fistula

Q: The complication of tracheoarterial fistula after tracheostomy occurs due to erosion from the tracheal tube into? (select one) 

A) anterior wall of the trachea 
B) posterior wall of the trachea


Answer: A

More than 80% of the patients die if tracheal tube ends up forming tracheoarterial fistula. It requires immediate bedside physical tamponade of the vessel by passing a finger through the tracheostomy stoma. The above information is vital to know that the innominate artery passes anteriorly across the trachea, and tamponade should be done by pressing the finger inside the tracheal stoma anterior towards the sternum.


#procedures



References:


1.. Ridley, R. W.; Zwischenberger, J. B. (2006-08-01). "Tracheoinnominate fistula: surgical management of an iatrogenic disaster". The Journal of Laryngology & Otology. 120 (8): 676–680.  


2.. Scalise P, Prunk SR, Healy D, Votto J. The incidence of tracheoarterial fistula in patients with chronic tracheostomy tubes: a retrospective study of 544 patients in a long-term care facility. Chest 2005; 128:3906. 



Friday, July 26, 2019

Organophosphate poisoning

Q: Atropine is considered as a mainstay antidote in organophosphate poisoning. The best marker of its effectiveness and titration is? (select one) 

A) respiratory secretions 
B)tachycardia 
C) mydriasis



Answer: A

Atropine is considered as an antidote of organophosphate poisoning. There is no maximum dose, and should be used till the symptoms are resolved. It may require continuous intravenous (IV) infusion. Poison center/toxicologist should be called immediately for the guidance of doses at every step.


 Atropine prevents cholinergic activation by competing for acetylcholine at muscarinic receptors. Resolution of respiratory secretions and bronchoconstriction are the best markers of resolving organophosphate poisoning and effectiveness of atropine. Heart rate and pupillary reactions can be very deceiving as they are subject to be highly influenced by hypoxemia, intravascular dehydration, and sympathetic stimulation.

#toxicology


Reference:

Eddleston M, Roberts D, Buckley N. Management of severe organophosphorus pesticide poisoning. Crit Care 2002; 6:259.

Thursday, July 25, 2019

Adrenal crisis

Q: All of the following are the symptoms of acute bilateral adrenal injury except? 

A) Circulatory shock 
B) Abdominal pain 
C) Fever 
D) Nausea &/or vomiting 
E) Hyperpigmented skin 


Answer:

Acute adrenal injury may occur due to hemorrhage, and/or infarction. The most common etiologies are motor vehicle accidents (blunt trauma), DIC, hemorrhage or emboli due to other reasons, sepsis and adrenal vein thrombosis.  Recently, Heparin-induced thrombocytopenia (HIT) has been recognized as a major cause of acute adrenal insufficiency.

Hyperpigmentation of skin requires time, and it is not one of the symptoms in acute adrenal shock.

#endocrinology


References:

1. Neary N, Nieman L. Adrenal insufficiency: etiology, diagnosis and treatment. Curr Opin Endocrinol Diabetes Obes. 2010;17(3):217–223.

2. Rao RH, Vagnucci AH, Amico JA. Bilateral massive adrenal hemorrhage: early recognition and treatment. Ann Intern Med 1989; 110:227.

3.  Warkentin TE, Safyan EL, Linkins LA. Heparin-induced thrombocytopenia presenting as bilateral adrenal hemorrhages. N Engl J Med 2015; 372:492.

Wednesday, July 24, 2019

Melena

Q: What amount of blood is enough to manifest melena?

A) 5 mL
B) 10 mL
C) 50 mL
D) 100 mL 
E) 250 mL

Answer: C

The objective of the above question is to highlight the point that the severity of gastrointestinal (GI) bleed cannot be predicted due to the presence of black tarry stool, known as melena. The only thing it signifies is that the location of blood is probably proximal to the ligament of Treitz, if obvious ENT source is excluded. 


Instead, of melena, if hematochezia i.e. maroon-colored stool is observed, it is probably due to lower GI bleeding or massive upper GI bleeding.


#Gastroenterology 



References:


1. Cappell MS, Friedel D. Initial management of acute upper gastrointestinal bleeding: from initial evaluation up to gastrointestinal endoscopy. Med Clin North Am 2008; 92:491. 


2.  Jensen DM, Machicado GA. Diagnosis and treatment of severe hematochezia. The role of urgent colonoscopy after purge. Gastroenterology 1988; 95:1569.

Tuesday, July 23, 2019

TLICS score

Q: In Thoracolumbar Injury Classification and Severity Score (TLICS), which of the spine injury morphology has the highest points? 

A) Compression fractures
B) Burst fractures
C) Rotational fractures 
D) Distraction fractures


Answer: D

Thoracolumbar Injury Classification and Severity Score (TLICS) is based on three categories i.e. injury morphology, neurologic status, and integrity of the posterior ligamentous complex -which are further subclassified. Score calculators are available on public search engines. In injury morphology, distraction fractures have the highest i.e., 4 points.


Describing the whole score is beyond the scope of this page but a score ≥5 suggests operative treatment, and a score ≤3 suggests stability.


#trauma

#neurology


References:


Vaccaro AR, Lehman RA Jr, Hurlbert RJ, et al. A new classification of thoracolumbar injuries: the importance of injury morphology, the integrity of the posterior ligamentous complex, and neurologic status. Spine (Phila Pa 1976) 2005; 30:2325.

Monday, July 22, 2019

false positive Allen test

Q: What is the most common cause of false-positive modified Allen test?


Answer:  Over-extension of the wrist.

Modified Allen test is considered a requirement before inserting a radial arterial line but unfortunately, many factors may give false positive or false negative tests. Top three reasons for false-positive modified Allen test are an overextension of the wrist, skin tension over the ulnar artery, and an inexperienced operator.

Pulse oximetry and plethysmography are reasonable alternatives for more objective evaluation of palmar arch perfusion than modified Allen test.

#procedure


References:

1. Barbeau GR, Arsenault F, Dugas L, et al. Evaluation of the ulnopalmar arterial arches with pulse oximetry and plethysmography: comparison with the Allen's test in 1010 patients. Am Heart J 2004; 147:489. 

2. Benit E, Vranckx P, Jaspers L, et al. Frequency of a positive modified Allen's test in 1,000 consecutive patients undergoing cardiac catheterization. Cathet Cardiovasc Diagn 1996; 38:352.

Sunday, July 21, 2019

Oral Milrinone

Q: Oral milrinone can be substituted for intravenous (IV) infusion if a long term central venous access cannot be obtained in a patient? (select one) 

A) True
B) False


Answer:  B

Unfortunately, oral phosphodiesterase inhibitors such as milrinone or vesnarinone failed to show any benefit, instead showed harm in major studies.  In comparison to IV infusion, oral phosphodiesterase inhibitors were found to cause more arrhythmias and so cardiac death. 

It is still not clear why oral form causes more harm. It could be due to longer accumulation and slower metabolism of the drugs.

#cardiology


References:

1. Packer M, Carver JR, Rodeheffer RJ, et al. Effect of oral milrinone on mortality in severe chronic heart failure. The PROMISE Study Research Group. N Engl J Med 1991; 325:1468. 

2. Amsallem E, Kasparian C, Haddour G, et al. Phosphodiesterase III inhibitors for heart failure. Cochrane Database Syst Rev 2005; :CD002230. 

3. Cohn JN, Goldstein SO, Greenberg BH, et al. A dose-dependent increase in mortality with vesnarinone among patients with severe heart failure. Vesnarinone Trial Investigators. N Engl J Med 1998; 339:1810.

Saturday, July 20, 2019

HIT and 4Ts score

Q: The 4 Ts score in the initial diagnosis of Heparin-Induced Thrombocytopenia (HIT) is found to be better than clinical judgment? (select one)

A) True
B) False


Answer:  B

 It is important to make awareness (again and again) that no score substitute or supersede the clinical judgment in the diagnosis of HIT. 4Ts is found to be a very reliable and a good guide in the presumptive diagnosis of HIT, but clinical judgment still carries the higher weight. This is to note that with any missed diagnosis of HIT, the mortality rose to 20% and with proper diagnosis, the mortality in HIT drops down to 2%. 


 #hematology 



 Reference: 


 Lo GK, Juhl D, Warkentin TE, et al. Evaluation of pretest clinical score (4 T's) for the diagnosis of heparin-induced thrombocytopenia in two clinical settings. J Thromb Haemost 2006; 4:759.

Friday, July 19, 2019

Tacrolimus

Q; What is the oral to the intravenous (IV) conversion of tacrolimus?


Answer: One-third to one-fifth

Whenever post-transplant patients get admitted to ICU, their anti-rejection meds (immunosuppressant) should be continued unless there is a contraindication. Tacrolimus is one of the most commonly used immunosuppressants. 


If a patient can't take oral form, the IV dose conversation is equal to one-third to one-fifth of the oral daily dose. Another important point is to administer it as a continuous infusion over 24 hours.


It is to remember that now a sublingual form of tacrolimus is available also.


#transplantation

#pharmacology


Reference: 


1. Prograf - https://www.astellas.us/docs/prograf.pdf 


2. Catherine A. Pennington, M.S., Pharm.D., BCPS Jeong M. Park, M.S., Pharm.D., BCPS Sublingual tacrolimus as an alternative to oral administration for solid organ transplant recipients American Journal of Health-System Pharmacy, Volume 72, Issue 4, 15 February 2015, Pages 277–284

Thursday, July 18, 2019

bacterial aortitis

Q: Which organism is most common in bacterial aortitis? 



 Answer: Salmonella 

Salmonella counts for about one-third of all bacterial aortitis. Unfortunately, about 5% of Salmonella infections become bacteremic, and they have a high tendency to adhere to damaged tissues particularly atherosclerotic vascular endothelium. Persisting fever or abdominal pain after salmonella infection should raise the concern for bacterial aortitis especially in smokers and male above the age of 50. Blood cultures are usually positive. Surgical repair is usually required.

Very interestingly, patients who are on chronic anti-acidity drugs like proton pump inhibitors (PPIs) have an increased risk of Salmonella bacteremia.


#surgical-critical-care

#infectious-diseases


References:


1. Oskoui R, Davis WA, Gomes MN (1993) Salmonella aortitis. Arch Intern Med 153:517–525. Barlow, G. D., & Green, S. T. (1999). 


2. A patient with fever and an abdominal aortic aneurysm. Postgraduate medical journal, 75(886), 479–480. doi:10.1136/pgmj.75.886.479

Wednesday, July 17, 2019

Fever in Adrenal crisis

Q: Low cortisol level? (select one)

A) May mask the fever
B) May exaggerate the fever


Answer: B

Fever secondary to low cortisol can be very deceiving. As sepsis itself can cause low cortisol, it sometimes becomes impossible to determine the actual cause of fever. On the flip side, treating adrenal insufficiency may make the fever go down, and help in the treatment.


#endocrinology




References:

1. Bleicken B, Hahner S, Ventz M, Quinkler M. Delayed diagnosis of adrenal insufficiency is common: a cross-sectional study in 216 patients. Am J Med Sci. 2010; 339: 525-531

  2. Dorin R. Qualls C. Crapo L. Diagnosis of adrenal insufficiency. Ann Intern Med. 2003; 139: 194-204

3. Husebye ES Allolio B Arlt W et al. Consensus statement on the diagnosis, treatment and follow-up of patients with primary adrenal insufficiency. J Intern Med. 2014; 275: 104-115

Tuesday, July 16, 2019

PEEP in prone

Q: Patient in prone position should be given higher than usual Positive End Expiratory Pressure (PEEP) to correct ventilation/perfusion (V/Q) mismatch? (select one)

A) True
B) False


Answer: B

Higher PEEP in patients with prone position while on a ventilator, may make V/Q mismatch worse. Higher applied PEEP in prone position redistribute blood flow to the dependent portion of the lung which is ventral portion in prone position, causing out of proportion redistribution of ventilation, resulting in worsening of  V/Q mismatch.


This is in contrast to regular supine patients where applied PEEP causes a homogeneous redistribution of ventilation and blood flow to the dependent portion, which is dorsal in this case.


#ventilator

#pulmonary


Reference:


Petersson J, Ax M, Frey J, et al. Positive end-expiratory pressure redistributes regional blood flow and ventilation differently in supine and prone humans. Anesthesiology 2010; 113:1361.

Monday, July 15, 2019

MG and thymectomy

Q: Thymectomy should be performed even in non-thymomatous myasthenia gravis (MG)? ( select one)

A) True
B) False


Answer: A

The famous multi-center MGTX trial, published in 2016 has pretty much resolved the above controversy. 126 patients were randomized between extended transsternal thymectomy plus alternate-day prednisone, and alternate-day prednisone alone. 

The former group did better over three years with the time-weighted average Quantitative Myasthenia Gravis score. Also, the average requirement for alternate-day prednisone and hospitalization for MG exacerbations was lower thymectomy group over three years. 

#surgical-critical-care


References:

 Wolfe GI, Kaminski HJ, Aban IB, et al. Randomized Trial of Thymectomy in Myasthenia Gravis. N Engl J Med 2016; 375:511.

Sunday, July 14, 2019

Epi and LA

Q: What's the etiology behind lactic acidosis from intravenous epinephrine infusion?


Answer: Out of all the intravenous vasopressors used in ICU, epinephrine is known to be the most notorious to cause lactic acidosis. Two mechanisms have been proposed. Postulation is that they may be happening together. One is the increased glycolytic activity in skeletal muscles and second is the hypoperfusion of gut causing lactic acidosis.

#pharmacology
#acid-base


Reference:

Day NP, Phu NH, Bethell DP, et al. The effects of dopamine and adrenaline infusions on acid-base balance and systemic haemodynamics in severe infection. Lancet 1996; 348:219.

Saturday, July 13, 2019

Twiddler's syndrome

Case: 62-year-old male with a history of congestive heart failure (CHF) is admitted to ICU with syncope, arrhythmia, and exacerbation of CHF. EP-cardiologist diagnosed patient with twiddler's syndrome, which is the twisting of the cardiac implantable electronic device (CIED) pulse generator within its pocket. Patients with twiddler's syndrome are more likely to have? (select one) 

A) bradyarrhythmia 
B) tachyarrhythmia


Answer: A

Twiddler's syndrome as described above is the twisting of the cardiac implantable electronic device (CIED) pulse generator within its pocket. It causes dislodgement of the lead and malfunction of the device. This leads to either lead impedance or increase in the bradycardic pacing threshold. Said that, with malfunction device, CIED may not respond in case of ventricular arrhythmia. Precautions at the initial insertion may prevent this complication.


#cardilogy
#procedure


Reference:

Chaara J, Sunthorn H. Twiddler syndrome. J Cardiovasc Electrophysiol 2014; 25:659.

Friday, July 12, 2019

PONV gender

Q: Which gender is more prone to develop postoperative nausea and vomiting (PONV)? (select one)

A) Male
B) Female


Answer: B

A meta-analysis of 22 studies comprising of 95,000 patients found that postpubertal female has an odds ratio [OR] of 2.57 to develop PONV.

#surgical-critical-care

#gastro-enterology


References:


1. Apfel CC, Heidrich FM, Jukar-Rao S, et al. Evidence-based analysis of risk factors for postoperative nausea and vomiting. Br J Anaesth 2012; 109:742. 


2. Sinclair DR, Chung F, Mezei G. Can postoperative nausea and vomiting be predicted? Anesthesiology 1999; 91:109. 

3. Eberhart LH, Morin AM, Guber D, et al. Applicability of risk scores for postoperative nausea and vomiting in adults to paediatric patients. Br J Anaesth 2004; 93:386. 

Thursday, July 11, 2019

WBC count in trauma

Q: High white blood cell (WBC) count after trauma is a predictor of poor outcome? (select one)

A) True
B) False


Answer: B

WBC count usually rises up to 12,000 to 20,000/mm3 with a left shift after trauma. It has no predictor value. The rise in WBC count could be only due to epinephrine release secondary to trauma (demargination), though viscus injury can also be the cause.

#trauma
#hematology


References:

Schnüriger B, Inaba K, Barmparas G, et al. Serial white blood cell counts in trauma: do they predict a hollow viscus injury? J Trauma 2010; 69:302.

Asimos AW, Gibbs MA, Marx JA, et al. Value of point-of-care blood testing in emergent trauma management. J Trauma 2000; 48:1101.

Wednesday, July 10, 2019

Protamine/heparin ratio

Q: What ratio of protamine/heparin is optimal for reversal of anticoagulation during post cardio-pulmonary bypass (CPB) phase?


Answer:  2.6 mg protamine per 100 units of heparin

 It is very interesting that if the ratio exceeds above 2.6 mg protamine per 100 units of heparin, this excess protamine is associated with inhibited platelet function and factor V activation, prolonged activated whole blood clotting time (ACT), and excessive bleeding after CPB.

#surgical critical-care


References:

1. Shore-Lesserson L, Baker RA, Ferraris VA, et al. The Society of Thoracic Surgeons, The Society of Cardiovascular Anesthesiologists, and The American Society of ExtraCorporeal Technology: Clinical Practice Guidelines-Anticoagulation During Cardiopulmonary Bypass. Ann Thorac Surg 2018; 105:650.

2. Boer C, Meesters MI, Veerhoek D, Vonk ABA. Anticoagulant and side-effects of protamine in cardiac surgery: a narrative review. Br J Anaesth 2018; 120:914. 

3. Mochizuki T, Olson PJ, Szlam F, et al. Protamine reversal of heparin affects platelet aggregation and activated clotting time after cardiopulmonary bypass. Anesth Analg 1998; 87:781. 

4. Ni Ainle F, Preston RJ, Jenkins PV, et al. Protamine sulfate down-regulates thrombin generation by inhibiting factor V activation. Blood 2009; 114:1658.

Tuesday, July 9, 2019

Thiamine def. and WE

Q: The best way to determine thiamine deficiency in Wernicke encephalopathy (WE) is via blood level? (select one)

A) True
B) False


Answer: B

There is no direct blood test available to document thiamine deficiency. The only test available is measuring erythrocyte thiamine transketolase (ETKA) before and after the addition of thiamine pyrophosphate (TPP). A low ETKA, along with a more than 25 percent stimulation, confirms thiamine deficiency. Also, serum thiamine or serum thiamine pyrophosphate level can be obtained by high-performance liquid chromatography. Both of these tests are special tests and are not easily available. Also, they do not correlate well with clinical signs. 


Thiamine deficiency gets establish by clinical signs and diagnostic criteria named Caine criteria. WE is diagnostic with two of the four Caine criteria positive: 

 ●Dietary deficiency 

 ●Oculomotor abnormalities 
 ●Cerebellar dysfunction 
 ●Either altered mental status or memory impairment


#neurology

#laboratory-science



References:

1. Galvin R, Bråthen G, Ivashynka A, et al. EFNS guidelines for diagnosis, therapy and prevention of Wernicke encephalopathy. Eur J Neurol 2010; 17:1408. 


2. Caine D, Halliday GM, Kril JJ, Harper CG. Operational criteria for the classification of chronic alcoholics: identification of Wernicke's encephalopathy. J Neurol Neurosurg Psychiatry 1997; 62:51. 

3. Leigh, D. Erythrocyte transketolase activity in the Wernicke-Korsakoff syndrome. Br J Psychol 1981; 138:153.  

4. Lu J, Frank EL. Rapid HPLC measurement of thiamine and its phosphate esters in whole blood. Clin Chem 2008; 54:901. 

Monday, July 8, 2019

refrigerated urine

Q: The excess urine can be refrigerated for future use, and can be examined later at 2 to 8 degrees? (select one)

A) True
B) False


Answer: B

It is true that excess urine can be refrigerated at 2 to 8 degrees Celsius but urine should always be examined at room temperature. Refrigerated urine should be re-warmed to room temperature before the examination. Ideally, a urine sample should be examined at room temperature within two hours of obtainment.

#laboratory-medicine
#nephrology


Reference:

Simerville JA, Maxted WC, Pahira JJ. Urinalysis: a comprehensive review. Am Fam Physician. 2005 Mar 15;71(6):1153-62.

Sunday, July 7, 2019

supranuclear gaze palsy after cardiac surgery

Q: A supranuclear gaze palsy is more common after? (select one) 

 A) mitral valve replacement 
B) aortic valve replacement


Answer: B

A Supranuclear gaze palsy is under-recognized but a well known complication after cardiac surgeries, specially aortic valve replacement and repair of an ascending aortic dissection. It is usually accompanied by spastic dysarthria and gait disorder. This is probably due to ischemic injury to the midbrain, or brainstem.


#surgical-critical-care

#neurology


References: 


1.  Solomon D, Ramat S, Tomsak RL, et al. Saccadic palsy after cardiac surgery: characteristics and pathogenesis. Ann Neurol 2008; 63:355.


2.  Devere TR, Lee AG, Hamill MB, et al. Acquired supranuclear ocular motor paresis following cardiovascular surgery. J Neuroophthalmol 1997; 17:189.


3. Mokri B, Ahlskog JE, Fulgham JR, Matsumoto JY. Syndrome resembling PSP after surgical repair of ascending aorta dissection or aneurysm. Neurology 2004; 62:971.

Saturday, July 6, 2019

Pleural effusion due to perforated esophagus

Q: Pleural effusion due to perforated esophagus would be? (selected one)

 A) exudative
B) transudative


Answer: A

Pleural effusion developed after esophageal perforation would probably be an exudative. Other marker would be lactate dehydrogenase (LDH) > 1000 international units/L. Most importantly, and diagnostic would be pleural fluid to serum amylase ratio >1. 


#pulmonary

#surgical-critical-care
#gastroenterology


References:


Good JT Jr, Antony VB, Reller LB, et al. The pathogenesis of the low pleural fluid pH in esophageal rupture. Am Rev Respir Dis 1983; 127:702. 


Drury M, Anderson W, Heffner JE. Diagnostic value of pleural fluid cytology in occult Boerhaave's syndrome. Chest 1992; 102:976.


Jon Arne Søreide and Asgaut Viste Esophageal perforation: diagnostic work-up and clinical decision-making in the first 24 hours Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine 2011 19:66