Sunday, September 30, 2018

LFT as a marker for appendiceal perforation

Q: Which of the following liver function test is described as a marker of appendiceal perforation?

A) Alanine transaminase (ALT) 

B) Aspartate transaminase (AST) 
C) Alkaline phosphatase (ALP) 
D) Gamma-glutamyl transpeptidase (GGT) 
E) Total bilirubin (TB)


Answer: E

Although elevation of total serum bilirubin stays mild around >1.0 mg/dL but if present in patients with acute appendicitis, the sensitivity for appendiceal perforation is 70 percent and specificity is 86 percent. It is a good adjuvant marker to help in deciding the emergency of the situation.

#surgicalcriticalcare
#hepatology


Reference:

Sand M, Bechara FG, Holland-Letz T, et al. Diagnostic value of hyperbilirubinemia as a predictive factor for appendiceal perforation in acute appendicitis. Am J Surg 2009; 198:193.  

Saturday, September 29, 2018

Liver Injury in vasopressin receptor antagonists

Q: Which of the following Vasopressin receptor antagonists should be used with extreme caution in patients with liver pathology? 

 A) tolvaptan 

B) mozavaptan 
C) satavaptan 
D) lixivaptan 
E) conivaptan


Answer: A

FDA has safety warnings for tolvaptan. Liver function test (LFT) should be obtained on any patient who is getting tolvaptan. This concern was raised when 2.5  fold increase in liver enzymes was noted while tolvaptan was getting studied for its efficacy on the progression of kidney failure in polycystic kidney disease.


#hepatology

#pharmacology
#nephrology



References:


1. Higashihara E, Torres VE, Chapman AB, et al. Tolvaptan in autosomal dominant polycystic kidney disease: three years' experience. Clin J Am Soc Nephrol 2011; 6:2499. 


2. Torres VE, Chapman AB, Devuyst O, et al. Tolvaptan in patients with autosomal dominant polycystic kidney disease. N Engl J Med 2012; 367:2407. Samsca (tolvaptan): Drug Warning - Potential Risk of Liver Injury


3. https://www.fda.gov/Drugs/DrugSafety/ucm350062.htm

Friday, September 28, 2018

7 classic signs of Typhoid fever

Q: What are the 7 classic signs of Typhoid fever?


Answer: 

1) Relative bradycardia 
2) Positive Widal test
3) High fever around 40 °C (104 °F) 
4) Rose spots on the lower chest and abdomen
5) Tender abdomen in the right lower quadrant
6) Green stool like pea soup
7) Fever usually rises in the afternoon


#infectiousdiseases

Read an excellent review here Typhoid fever (emedicine.com)

https://emedicine.medscape.com/article/231135-overview#showall

Thursday, September 27, 2018

Nail polish affect on pulse-ox

Q: Which of the following nail polish is found to least affect the pulse oximeter readings?

A) black
B) green
C) blue 
D) red 
E) brown


Answer:  D

Nail polishes, particularly older brands can affect the pulse oximeter (pulse-ox) readings. The underlying issue is the ability of the nail polish to absorb the light at 660 nm-940 nm. The blue nail polish tends to give the highest discrepancy, almost by the difference of 6 percent - followed by green, black and brown nail polishes. Red nail polish tends to least affect the pulse-ox readings. Similarly, artificial nails can make pulse-ox readings very unreliable. In such situations, pulse ox probe should be placed either side to side on the finger or at the other locations such as earlobes.

#oxygenation



References:

1. Hinkelbein J, Genzwuerker HV, Sogl R, Fiedler F. Effect of nail polish on oxygen saturation determined by pulse oximetry in critically ill patients. Resuscitation 2007; 72:82. 

2. Chan MM, Chan MM, Chan ED. What is the effect of fingernail polish on pulse oximetry? Chest 2003; 123:2163. 

3. Hinkelbein J, Koehler H, Genzwuerker HV, Fiedler F. Artificial acrylic finger nails may alter pulse oximetry measurement. Resuscitation 2007; 74:75.

Wednesday, September 26, 2018

Cytokines adsorption in CRRT

Q: The hemofilter in Continuous Renal Replacement Therapy (CRRT) is? (select one)

 A) Positively charged
B) Negatively charged


 Answer: B

The hemofilter, also known as hemodialyzer in CRRT machines are high-permeability, high-flux biocompatible membranes with negative charge. This allows more adsorption and removal of some solutes, particularly cytokines. 


#nephrology



Reference:


Noriyuki Hattori, Shigeto Oda, Cytokine-adsorbing hemofilter: old but new modality for septic acute kidney injury,  Renal Replacement Therapy 20162:41

Tuesday, September 25, 2018

Over the counter drugs, Serotonin syndrome and failure of antiretroviral therapy

Q: 48 year old male is admitted to ICU with serotonin syndrome 3 weeks after he was started on Citalopram on an outpatient basis. Patient also has an history of HIV and on admission his viral load appears to be high. Family reported him to be very health conscious since his diagnosis of HIV few years ago, and fully compliant with his prescriptions. Also, he is taking many nutritional products to keep himself healthy. Which of the following over the counter drug is the most probable cause of his serotonin syndrome and failure of anti-retroviral therapy?

A) Coenzyme Q10 
B) Fish oil 
C) Ginkgo biloba 
D) Green tea 
E) St. John's wort 


Answer: E

Although any over the counter drug can downgrade or upgrade the effects of any prescription drug but St. John's wort, the common name for Hypericum perforatum, should be used with caution in patients with centrally acting medicines as they are very prone to cause serotonin syndrome. Also, it can cause failure of antiretroviral therapy in HIV patients. There is a component in St. John's wort called hyperforin which induces the cytochrome P450 3A4 (CYP3A4) system, which metabolizes many drugs including protease inhibitors, cyclosporine, oral contraceptives, warfarin, and digoxin. FDA has advisory against its use with HAART (antiretroviral regimen) medications. 3


Ginkgo biloba tends to do more coagulopathy. Other choices given above are relatively safe.

#pharmacology




References:


1. Wong AH, Smith M, Boon HS. Herbal remedies in psychiatric practice. Arch Gen Psychiatry 1998; 55:1033. 


2. Lantz MS, Buchalter E, Giambanco V. St. John's wort and antidepressant drug interactions in the elderly. J Geriatr Psychiatry Neurol 1999; 12:7.

3. Food & Drug Administration: Center for Drug Evaluation and Research. FDA Public Health Advisory - Risk of drug interactions with St John's wort and indinavir and other drugs. February 10, 2000. Last accessed on 1-27-2009.

Monday, September 24, 2018

Rockall, Blatchford, and AIMS65 scoring systems

Q: Rockall, Blatchford, and AIMS65 - are the scoring system to assess the severity of

A) Pneumonia
B) ARDS
C) Upper gastro-intestinal  (GI) bleed
D) Increase intra-cranial pressure
E) Liver failure


Answer: C

All of the said scores assess the severity of upper GI bleed. The Rockall score 1,2  can be used only when endoscopic data is available. In contrast, the Glasgow Blatchford score 3 is useful when the patient is seen for the first time clinically. The simpler version of Blatchford score is called a modified Glasgow Blatchford score 4.  AIMS65 5 is an easy mnemonic. It stands for Albumin, INR, Mental status, Systolic blood pressure and Age (older than 65 years).


All these scores are available online and have been rigorously tested. 6, 7


#gastroenetrolgy 



References:

1. Rockall TA, Logan RF, Devlin HB, Northfield TC. Selection of patients for early discharge or outpatient care after acute upper gastrointestinal haemorrhage. National Audit of Acute Upper Gastrointestinal Haemorrhage. Lancet 1996; 347:1138. 

2. Church NI, Dallal HJ, Masson J, et al. Validity of the Rockall scoring system after endoscopic therapy for bleeding peptic ulcer: a prospective cohort study. Gastrointest Endosc 2006; 63:606.

3. Blatchford O, Murray WR, Blatchford M. A risk score to predict need for treatment for upper-gastrointestinal haemorrhage. Lancet 2000; 356:1318. 

4. Cheng DW, Lu YW, Teller T, et al. A modified Glasgow Blatchford Score improves risk stratification in upper gastrointestinal bleed: a prospective comparison of scoring systems. Aliment Pharmacol Ther 2012; 36:782. 

5.  Hyett BH, Abougergi MS, Charpentier JP, et al. The AIMS65 score compared with the Glasgow-Blatchford score in predicting outcomes in upper GI bleeding. Gastrointest Endosc 2013; 77:551. 

6. Stanley AJ, Laine L, Dalton HR, et al. Comparison of risk scoring systems for patients presenting with upper gastrointestinal bleeding: international multicentre prospective study. BMJ 2017; 356:i6432. 

7. Tang Y, Shen J, Zhang F, et al. Scoring systems used to predict mortality in patients with acute upper gastrointestinal bleeding in the ED. Am J Emerg Med 2018; 36:27.

Sunday, September 23, 2018

Delayed emesis in chemotherapy

Q: Out of the following, which chemotherapy agent is more prone to cause delayed emesis?

A) cisplatin 

B) cyclophosphamide 
C) doxorubicin 
D) fluorouracil 
E) leucovorin


Answer: A

Delayed emesis can fool physicians who are not experienced in dealing with chemotherapy on a regular basis. It is defined as emesis which occurs more than 24 hours after chemotherapy. It can occur with any chemotherapeutic agent but high-dose cisplatin is more prone to cause it. High vigilance and following the appropriate drug regimen to prevent such episodes can be very helpful.



#oncology
#pharmacology
#gastroenterology



References:

1. Olver I, Paska W, Depierre A, et al. A multicentre, double-blind study comparing placebo, ondansetron and ondansetron plus dexamethasone for the control of cisplatin-induced delayed emesis. Ondansetron Delayed Emesis Study Group. Ann Oncol 1996; 7:945.

2. Kris MG, Gralla RJ, Tyson LB, et al. Controlling delayed vomiting: double-blind, randomized trial comparing placebo, dexamethasone alone, and metoclopramide plus dexamethasone in patients receiving cisplatin. J Clin Oncol 1989; 7:108.

Saturday, September 22, 2018

EKG in uremic pericarditis

Q: Chronic uremic pericarditis presents on EKG as more intense diffuse ST- and T-wave elevations than other forms of pericarditis? 

A) True 
B) False 



Answer: False 

Unlike other pericarditis, uremic pericarditis does not produce diffuse ST- and T-wave elevations on EKG. This is due to the lack of penetration of the inflammatory cells into the myocardium. And, if uremic pericarditis shows diffuse ST elevations on EKG, it suggests other underlying disease process. 

#cardiology
#nephrology



References:

Gunukula SR, Spodick DH. Pericardial disease in renal patients. Semin Nephrol 2001; 21:52.

Friday, September 21, 2018

Smoking and Warfarin

Q: Smoking tends to  ______________  the dose requirement of warfarin? (select one)

A) Increase
B) Decrease


Answer: A

Smoking tends to increase the dose requirement of warfarin by about 10-12 percent. The increase clearance of warfarin in smokers is probably due to induction of hepatic cytochrome P-450 activity (eg, CYP1A1, CYP1A2, CYP2E1) by polycyclic aromatic hydrocarbons, and not by nicotine in the cigarette smoke. Similar effects can happen in marijuana smoking.


#pharmacology


References: 

1. Nathisuwan S, Dilokthornsakul P, Chaiyakunapruk N, et al. Assessing evidence of interaction between smoking and warfarin: a systematic review and meta-analysis. Chest 2011; 139:1130. 

2. Yamreudeewong W, Wong HK, Brausch LM, Pulley KR. Probable interaction between warfarin and marijuana smoking. Ann Pharmacother 2009; 43:1347. 

Thursday, September 20, 2018

Alexia

Q: What is Alexia? 

 Answer: Alexia is the inability to recognize or comprehend written language. In other words, "Alexia" refers to a loss of already developed reading ability. 

 Alexia typically occurs after a stroke or damage to the dominant hemisphere of the brain. Usually, it occurs with other symptoms of stroke but pure alexia can occur too, where an individual's ability to produce written language is spared even though they are unable to understand written text.

#neurology



Reference: 


Petersen, A., Vangkilde, S., Fabricius, C., Iversen, H., Delfi, T., & Starrfelt, R. (2015). "Visual Attention in Posterior Stroke and Relations to Alexia". Neuropsychologia. 58: 1521

Wednesday, September 19, 2018

Cardiac device and Archimedes screw

Q: Which of the cardiac device works on the principle of ancient Archimedes screw? 

A) Impella 
B) Tandem Heart
C) Intra Aortic Balloon Pump (IABP)
D) Intravenous percutaneous transient pacemaker (IVPM)
E) Electrical cardioversion (EC)


Answer: 

A Impella is left ventricle to aorta assist device which is an axial flow pump on the principle of the Archimedes screw. The Impella is usually placed percutaneously retrograde via femoral artery across the aortic valve into the left ventricle. A revolving pump draws blood out of the left ventricle (de-loading) and ejects it proximally into the ascending aorta.



The Tandem Heart is a left atrial to aorta assist devices where percutaneous catheter is passed to right atrium and via transseptal puncture into left atrium. Tandem Heart works via centrifugal pump.

IABP works on inflation/deflation principle.

IVPM is an electric pacer and  EC is an electric jolt. 

#cardiology
#hemodynamics




References:

1 Siegenthaler MP, Brehm K, Strecker T, et al. The Impella Recover microaxial left ventricular assist device reduces mortality for postcardiotomy failure: a three-center experience. J Thorac Cardiovasc Surg 2004; 127:812. 

2.  Basra SS, Loyalka P, Kar B. Current status of percutaneous ventricular assist devices for cardiogenic shock. Curr Opin Cardiol 2011; 26:548.

Tuesday, September 18, 2018

Sugammadex in ICU

Q: Sugammadex reverses the neuromuscular blockade (NMBAs) of all of the following except

 A) rocuronium 
B) vecuronium 
C) pancuronium 
D) pipecuronium 
E) succinylcholine


Answer: 

 Sugammadex only inactivates steroidal NMBAs by encapsulating them. It works best for rocuronium. It has no effect on succinylcholine which is a different class of NMBAs. This is an important drug/reversal to know for an intensivist as in case if rocuronium is used for intubation, and intubation turns out to be a difficult situation, sugammadex can reverse the muscular blockade and patient can be rescued with bag and mask ventilation. The dose in such scenario is 16 mg/kg. Reversal occurs within three minutes. Care should be taken in the calculation of dose as a higher dose may cause anaphylaxis or bradycardia. It is not recommended in end-stage renal disease (ESRD) patients.

#procedures
#pharmacology


References:


1. Bom A, Hope F, Rutherford S, Thomson K. Preclinical pharmacology of sugammadex. J Crit Care 2009; 24:29. 

2. Hristovska AM, Duch P, Allingstrup M, Afshari A. Efficacy and safety of sugammadex versus neostigmine in reversing neuromuscular blockade in adults. Cochrane Database Syst Rev 2017; 8:CD012763. 

3. Sørensen MK, Bretlau C, Gätke MR, et al. Rapid sequence induction and intubation with rocuronium-sugammadex compared with succinylcholine: a randomized trial. Br J Anaesth 2012; 108:682.

4. Cammu G, Van Vlem B, van den Heuvel M, et al. Dialysability of sugammadex and its complex with rocuronium in intensive care patients with severe renal impairment. Br J Anaesth 2012; 109:382.  

5. Tsur A, Kalansky A. Hypersensitivity associated with sugammadex administration: a systematic review. Anaesthesia 2014; 69:1251. 

6. Bhavani SS. Severe bradycardia and asystole after sugammadex. Br J Anaesth 2018; 121:95.

Monday, September 17, 2018

piperacillin-tazobactam + vancomycin = AKI

Q: Combined use of which two very commonly used antibiotics in ICU is known to have higher risk of acute kidney injury (AKI)?


Answer: Concomitant use of piperacillin-tazobactam (zosyn) and vancomycin has been reported to have higher incidence of AKI in comparison to other combinations.

#infectiousdiseases
#nephrology




References:

1. Hammond DA, Smith MN, Li C, et al. Systematic Review and Meta-Analysis of Acute Kidney Injury Associated with Concomitant Vancomycin and Piperacillin/tazobactam. Clin Infect Dis 2016.

2. Navalkele B, Pogue JM, Karino S, et al. Risk of Acute Kidney Injury in Patients on Concomitant Vancomycin and Piperacillin-Tazobactam Compared to Those on Vancomycin and Cefepime. Clin Infect Dis 2017; 64:116. 

3. Rutter WC, Cox JN, Martin CA, et al. Nephrotoxicity during Vancomycin Therapy in Combination with Piperacillin-Tazobactam or Cefepime. Antimicrob Agents Chemother 2017; 61.

Sunday, September 16, 2018

Thiamine before glucose in acute alcohol ingestion - True?

Q: 44 year old male with known history of alcohol abuse - a frequent flyer to ED - presented again with acute alcohol ingestion. Blood glucose noted to be 40 mg/dL. Admitting resident decided to hold infusion of dextrose before administering thiamine to avoid the risk of Wernicke's encephalopathy. Being an attending, do you agree with the decision? (select one)

A) Yes
B) No


Answer: No

There is no real evidence based literature to support the classic practice of holding dextrose infusion before thiamine in alcoholic patients to avoid Wernicke's encephalopathy. Risks and benefits should be weighed including the complications of  hypoglycemia. 

#neurology



References:

1. Schabelman E, Kuo D. Glucose before thiamine for Wernicke encephalopathy: a literature review. J Emerg Med 2012; 42:488. 

2. Hack JB, Hoffman RS. Thiamine before glucose to prevent Wernicke encephalopathy: examining the conventional wisdom. JAMA 1998; 279:583.

Saturday, September 15, 2018

Blurring of vision on forward bending of the head

Q: Blurring of vision on forward bending of the head is a sign of? 

A) a migraine headache 
B) pituitary mass
C) optic neuritis 
D) raised intracranial pressure (ICP) 
E) pheochromocytoma


Answer: D

Blurring of vision on forward bending of the head should prompt a physician to think of high ICP, particularly if it improves with sitting up (or waking up in the morning), or if associated with double vision or loss of coordination and balance. This is a significant point to learn as the foremost and the first step in the management of increased ICP is to elevate the head of the bed. 

A migraine headache comes in various forms and flavors and literature is so vast that it is beyond the scope of this pearl. But it usually does not get worse with forward bending or improves with sitting up (choice A). 

Pituitary mass usually presents with a visual defect (choice B). 

Optic Neuritis is marked by painful, monocular visual loss (choice C). 

Pheochromocytoma carries systemic signs of generalized sweating, tachycardia, and paroxysmal hypertension (choice E).


#neurology



References / further read: 

1. Brain Trauma Foundation, American Association of Neurological Surgeons, Congress of Neurological Surgeons, et al. Guidelines for the management of severe traumatic brain injury. VII. Intracranial pressure monitoring technology. J Neurotrauma 2007; 24 Suppl 1:S45. 

2.  Hainer BL, Matheson EM. Approach to acute headache in adults. Am Fam Physician 2013; 87:682. 

3.  Dodick D. Headache as a symptom of ominous disease. What are the warning signals? Postgrad Med 1997; 101:46.

Friday, September 14, 2018

Sildenafil and Cyanopsia

Q: Sildenafil causes Cyanopsia because?

A) Trade brand Viagra is colored blue
B) It only occurs with Sildenafil
C) It sensitizes the retinal rod cells
D) It is a sign of underlying cataract
E) If it occurs, it should not be used in pulmonary hypertension


Answer: C

Sildenafil and other Phosphodiesterase-5 (PDE5) Inhibitors have become an integral part of pulmonary hypertension and has been used in ICU with increased frequency. The eye's lens has a yellow natural tint and it reduces the intensity of blue light before it reaches the retina. PD5-inhibitors decrease the enzymatic activity, sensitize the rod cells of the retina and enhanced its activity causing bluish tint in the vision.


Although infamously viagra is called blue pill, its color has nothing to do with bluish tint of vision (choice A).

All PD-5- Inhibitors can cause this effect (choice B).

Actually, bluish tint in the vision is a post-cataract surgery effect due to loss of naturally present yellow tint lens or with the artificially instilled clear lens (choice D).

It is usually a benign effect and should not stop clinicians from utilizing its potent advantage in pulmonary hypertension (choice E).

#pharmacology
#pulmonary



References:

1. Laties A, Zrenner E. - Viagra (sildenafil citrate) and ophthalmology.  Prog Retin Eye Res. 2002 Sep;21(5):485-506. 

 2. Hayashi, K., & Hayashi, H. (2006). Visual function in patients with yellow tinted intraocular lenses compared with vision in patients with non-tinted intraocular lenses. British Journal of Ophthalmology, 90, 1019-1023.


Thursday, September 13, 2018

"My Five Moments for Hand Hygiene"

Q: What are the "My Five Moments for Hand Hygiene"? 

Answer: 

 "My Five Moments for Hand Hygiene" is a major global effort (part of SAVES LIVES) led by the World Health Organization (WHO). It defines the key moments when health care workers should perform hand hygiene

1) Before touching a patient
2) Before clean/aseptic procedures
3) After body fluid exposure/risk
4) After touching a patient
5) After touching patient surroundings

Hand hygiene is defined as either hand washing with soap and water or the use of alcohol-based hand disinfection (except in C.diff exposure). 

 #infectiousdiseases



Reference:

World Health Organization. SAVE LIVES: Clean Your Hands: WHO's global annual campaign http://www.who.int/infection-prevention/en/



Wednesday, September 12, 2018

Platelet increment after its transfusion

Q: How long does it take to peak platelet count after its transfusion? 

Answer: About 10 minutes to an hour 

It takes about 10 to 60 minutes after a platelet transfusion to have its peak value. Transfused platelets usually survive in the blood for about three days in contrast to bone marrow produced platelets which have a half-life of about ten days.

 A transfusion of one apheresis platelet, which is an equivalent to six units of pooled platelets approximately increase platelet count by 30,000/microL in an average adult.

#hematology



References:


1. Slichter SJ. Platelet transfusion therapy. Hematol Oncol Clin North Am 2007; 21:697. 


2. McCullough J. Overview of platelet transfusion. Semin Hematol 2010; 47:235.

Tuesday, September 11, 2018

Vasodilators in severe AS

Q: What is the peril of using vasodilators in the presence of a severe fixed aortic stenosis?


Answer: Use of vasodilators in the presence of a severe fixed aortic valve stenosis reduces the systemic blood pressure and reduces the coronary artery perfusion pressure. Likelihood of coronary artery disease in such a patient is high and decrease coronary perfusion may lead to myocardial ischemia. These patients are "afterload fixed and preload dependent"! so vasodilators do not serve the purpose of afterload reduction. 

Vasodilators in mild to moderate AS patients can still be beneficial but should be managed only by the experienced physicians.

#cardiology



References: 


Zakkar M, Bryan A J, Angelini G D. Aortic stenosis: diagnosis and management BMJ 2016; 355 :i5425

Monday, September 10, 2018

Anisocoria

Q: Anisocoria -unequal pupils - can occur in which of the following

A) Horner syndrome due to carotid dissection

B) Third nerve palsy due to an aneurysm or uncal herniation.
C) Previous cataract extraction
D) Uveitis
E) All of the above



Answer: E

The objective of the above question is to emphasize that anisocoria can happen from life-threatening situations as in choices A and B to relatively benign conditions like in choices C and D. It is extremely important to consider patients' underlying history before embarking on "million dollars workup". On the same note, any newly developed anisocoria in ICU in an intubated patient or with other neurological sign should promptly ring a bell. 

#neurology



References: 

1. Levin LA. The perils of PERRLA. Ann Intern Med. 2007 Apr 17. 146(8):615-6. 

2. Thompson S, Pilley SF. Unequal pupils. A flow chart for sorting out the anisocorias. Surv Ophthalmol. 1976 Jul-Aug. 21(1):45-8. 

3. Martin TJ. Horner's syndrome, Pseudo-Horner's syndrome, and simple anisocoria. Curr Neurol Neurosci Rep. 2007 Sep. 7(5):397-406.

Sunday, September 9, 2018

Minimizing Barotrauma

Q: All of the following can decrease the chances of barotrauma and bronchopleural fistula in ventilated patients except?

A) Use of small tidal volumes
B) Allowing permissive hypercapnia
C) Lower PEEP
D) Higher inspiratory flow rate
E) Low-compressible-volume, low-compliance ventilator circuit


Answer: D

A, B and C are well-known choices to avoid barotrauma in ventilated patients as lower the volume and pressure via a ventilator, lower are chances of barotrauma. Permissive hypercapnia is (choice B) very well tolerated by a diseased lung and should not deter a clinician from utilizing this advantage as risks due to barotrauma are higher than risks of permissive hypercapnia.

Higher the inspiratory flow rate, higher would be the peak inspiratory pressure and consequently higher would be the risk of barotrauma (choice D).

Some emphasis should be put on the education of breathing circuits as the actual tidal volume get affected by the compliance of the breathing circuit. Low-compressible-volume, low-compliance ventilator circuit helps in keeping the actual tidal volume to lower limits (Choice E). 

#ventilators
#pulmonology



References:

1. Laffey JG, Engelberts D, Kavanagh BP. Buffering hypercapnic acidosis worsens acute lung injury. Am J Respir Crit Care Med 2000; 161:141.

2. Laffey JG, Tanaka M, Engelberts D, et al. Therapeutic hypercapnia reduces pulmonary and systemic injury following in vivo lung reperfusion. Am J Respir Crit Care Med 2000; 162:2287.

3. Yang SC, Yang SP. Effects of inspiratory flow waveforms on lung mechanics, gas exchange, and respiratory metabolism in COPD patients during mechanical ventilation. Chest 2002; 122:2096.

4. Masselli GM, Silvestri S, Sciuto SA, Cappa P. - Circuit compliance compensation in lung protective ventilation. Conf Proc IEEE Eng Med Biol Soc. 2006;1:5603-6.

Saturday, September 8, 2018

Hypokalemic TPP

Q: 24 year old male from Thailand is brought from college volleyball field with full body muscle weakness worsening very quickly. Diagnosis of Thyrotoxic Periodic Paralysis (TPP) with hypokalemia is made, but no improvement with potassium replacement noticed while in ED. Patient is now admitted to ICU. Which of the following drug tends to help patients with refractory thyrotoxic Periodic Paralysis (TPP)?

A) Intravenous calcium
B) Doubling the dose of Potassium
C) Intravenous (IV) Propranolol
D) Clonidine
E) Intravenous (IV) Thyroxine



Answer: C

Periodic paralysis (PP) is a well known  autosomal dominant disease, manifests by painless muscle weakness and precipitates by exercise, fasting, or high-carbohydrate foods. PP can also be an acquired disease in association with hyperthyroidism. TPP is classically get presented in Asian males. If potassium replacement does not resolve an attack, IV propranolol may reverse the weakness and the hypokalemia. The dose is 1 mg of IV propranolol every 10 minutes up to a maximum dose of 3 mg. Propranolol is a beta adrenergic blocker, and reverses the excessive stimulation of the sodium-potassium ATPase and reverses drive of potassium into the cells. 

#endocrinology
#electrolytes
References: 

1. Shayne P, Hart A. Thyrotoxic periodic paralysis terminated with intravenous propranolol. Ann Emerg Med 1994; 24:736. 

2. Birkhahn RH, Gaeta TJ, Melniker L. Thyrotoxic periodic paralysis and intravenous propranolol in the emergency setting. J Emerg Med 2000; 18:199.

Friday, September 7, 2018

IVF as an analgesia

Q: Intravenous fluid (IVF) resuscitation can act as an adjuvant analgesia? (select one)

A) True
B) False


Answer: True

In many conditions, where dehydration, hypovolemia or capillary leak syndrome becomes a part of underlying pathophysiology, adequate IVF resuscitation and restoration of euvolemia helps in relieving pain. Hemoconcentration aggravates the ischemic pain and proper hydration attenuates underlying ischemia. On the other hand, care should be taken to avoid aggressive resuscitation as most of these patients have hypoalbuminemia and decrease colloid pressure may increase the third space edema resulting in compartment syndromes, like intra-abdominal hypertension in septic shock patients from over-zealous IVF resuscitation.

#resuscitation




Reference: 

White, Paul F.Maharaj and Co.Preoperative Intravenous Fluid Therapy Decreases Postoperative Nausea and Pain in High Risk Patients - Anesthesia & Analgesia: March 2005 - Volume 100 - Issue 3 - p 675-682

Thursday, September 6, 2018

primary hypotensive transfusion reactions

Q: Which of the following blood product is more prone to cause "primary hypotensive transfusion reactions"? 

 A) pRBC 
B) Fresh Frozen Plasma 
C) Platelets 
D) Cryoprecipitate 


 Answer:

Primary hypotensive transfusion reactions is an exclusive transfusion reactions associated only with hypotension. It is not a part of any other transfusion reactions like acute hemolytic reaction, transfusion-related acute lung injury (TRALI), and anaphylaxis.  The mechanism behind this phenomenon is thought to be vasoactive kinins like bradykinin. It occurs mostly with platelet transfusion. It is also reported  during apheresis procedures.

#hematology



 Reference: 

 Hume HA, Popovsky MA, Benson K, et al. Hypotensive reactions: a previously uncharacterized complication of platelet transfusion? Transfusion 1996; 36:904.

Wednesday, September 5, 2018

Managing Cold Aglutinin in Surgical Patients

Q: 54 year old male with known coronary artery disease (CAD) is admitted to ICU with severe ischemic cardiogenic shock. After hemodynamic stabilization, bypass surgery is recommended by cardiology service. Patient has a documented history of Cold Agglutinin Disease. All of the following precautions or interventions may help except?

A) Plasmapheresis just prior to surgery with avoidance to any exposure to cold solution 
B) Forced warm air on the operative field 
C) Intravenous solutions and blood products to be warmed up appropriately before infusion 
D) Post-op room temperature at adequate levels
E) Emergent splenectomy if patient crash during surgery due to cold agglutination



Answer:  E

Patients with cold agglutinin impose specific challenges when it comes to surgery due to exposure of cold at various steps of surgery. The whole staff need to be aware of exposure to cold in such patients prior to surgery. Beside precautions (choices B, C , and D).

Plasmapheresis (Choice A) just prior to surgery with avoidance to any exposure to cold solution may be an option in very fragile patients. Effect of plasmapheresis lasts for five days to get through the immediate operative and post-operative period. 

Interestingly, spleen is not the organ of red cell destruction in cold agglutinin disease.  It is liver. So splenectomy may not be of much help. It is helpful in rare subgroup of patients who have cold agglutinin disease in with autoantibody IgG. (Choice E) 

#surgicalcriticalcare
#hematology


References: 

1. Berentsen S, Ulvestad E, Langholm R, et al. Primary chronic cold agglutinin disease: a population based clinical study of 86 patients. Haematologica 2006; 91:460. 

2.  Bedrosian CL, Simel DL. Cold hemagglutinin disease in the operating room. South Med J 1987; 80:466. 

3. Beebe DS, Bergen L, Palahniuk RJ. Anesthetic management of a patient with severe cold agglutinin hemolytic anemia utilizing forced air warming. Anesth Analg 1993; 76:1144. 

4. Talisman R, Lin JT, Soroff HS, Galanakis D. Gangrene of the back, buttocks, fingers, and toes caused by transient cold agglutinemia induced by a cooling blanket in a patient with sepsis. Surgery 1998; 123:592. 

5. Barbara DW, Mauermann WJ, Neal JR, et al. Cold agglutinins in patients undergoing cardiac surgery requiring cardiopulmonary bypass. J Thorac Cardiovasc Surg 2013; 146:668.

6. Zoppi M, Oppliger R, Althaus U, Nydegger U. Reduction of plasma cold agglutinin titers by means of plasmapheresis to prepare a patient for coronary bypass surgery. Infusionsther Transfusionsmed 1993; 20:19.

Tuesday, September 4, 2018

Drugs causing lymphadenopathy

Q: 58 year old female with a past medical history of hypertension, seizure, and chronic diabetic foot, on chronic antibiotics, is admitted to ICU with a status epilepticus after she runs out of her prescriptions. On physical exam, you noticed generalized lymphadenopathy.  Which of the following commonly used drugs may cause lymphadenopathy? 

A) Atenolol 
B) Captopril 
C) Cephalosporins 
D) Phenytoin
E) All of the above


Answer:  E

The objective of the above question is to highlight a less well-known fact that drugs itself can be a source of otherwise unexplained lymphadenopathy. The list of those drugs is long. The major pathogenesis of lymphadenopathy by drugs is due to underlying serum sickness. This lymphadenopathy may be associated with fever, arthralgias, and rash.

#physicalexam
#pharmacology



Reference: 

Pangalis GA, Vassilakopoulos TP, Boussiotis VA, Fessas P. Clinical approach to lymphadenopathy. Semin Oncol 1993; 20:570.

Monday, September 3, 2018

CHF exacerbation

Q: All of the following are the clinical signs of acute decompensated congestive heart failure (CHF) - popularly known as exacerbation of CHF - except?

A) Elevated jugular venous pressure
B) Positive hepatojugular reflux test
C) A tender and enlarged liver
D) Pleural effusion, more frequent at left
E) Leg edema


Answer: D

In acute decompensated CHF, the right pleural effusion is more frequent than left pleural effusion. All others are positive signs of CHF. On auscultation, a third heart sound and a laterally displaced apex beat may be audible. Other additional murmurs may give tips on a possible cause of CHF like mitral or tricuspid valve pathology.

#physical exam
#cardiology



References: 

1. Onwuanyi A, Taylor M. Acute decompensated heart failure: pathophysiology and treatment. Am J Cardiol. 2007 Mar 26. 99 (6B):25D-30D. 

2.  Henes J, Rosenberger P. Systolic heart failure: diagnosis and therapy. Curr Opin Anaesthesiol. 2016 Feb. 29 (1):55-60.

Sunday, September 2, 2018

postoperative ileus

Q: All of the following may lead to prolonged postoperative ileus except?

A) Hyperkalemia 
B) Hypomagnesemia
C) Uremia 
D) Gallbladder dysfunction
E) Pancreatitis 



Answer: A

Laboratory or radiological workup should be initiated or monitored daily if postoperative ileus lasts more than 48 to 72 hours despite all appropriate measures. Various factors may lead to prolonged postoperative ileus in surgical ICU including hypokalemia, hypomagnesemia, anemia, infection (leucocytosis), ischemia (lactate elevation), renal dysfunction (uremia), gallbladder dysfunction (liver function test or ultrasound of abdomen), and pancreatitis (amylase & lipase elevation).

#surgicalcriticalcare
#gastroenterology


References:

1. Person B, Wexner SD. The management of postoperative ileus. Curr Probl Surg. 2006 Jan. 43(1):6-65. 

2. Mattei P, Rombeau JL. Review of the pathophysiology and management of postoperative ileus. World J Surg. 2006 Aug. 30(8):1382-91 

3. Behm B, Stollman N. Postoperative ileus: etiologies and interventions. Clin Gastroenterol Hepatol. 2003 Mar. 1(2):71-80. 

4. Carter S. The surgical team and outcomes management: focus on postoperative ileus. J Perianesth Nurs. 2006 Apr. 21(2A Suppl):S2-6.

Saturday, September 1, 2018

HTN and shift of CPP auto-regulatory curve

Q: Patients with chronic hypertension, may tolerate higher cerebral perfusion pressure (CPP) as their autoregulatory curve may have been shifted to the? (select one)

A) right 
B) left


Answer: A

High CPP leads to hypertensive encephalopathy and consequently to cerebral edema due to the eventual breakdown of autoregulation. But patients with previous chronic hypertension have their autoregulatory curve shifted to the right, and can tolerate higher CPP in comparison to other patients. The limit to this threshold in hypertensive patients is found to be around CPP of 120 mmHg.


#neurosurgery
#neurology



References:

1. Strandgaard S, Paulson OB. Cerebral blood flow and its pathophysiology in hypertension. Am J Hypertens 1989; 2:486.

2. Lassen NA, Agnoli A. The upper limit of autoregulation of cerebral blood flow--on the pathogenesis of hypertensive encepholopathy. Scand J Clin Lab Invest 1972; 30:113. Kaplan NM. Management of hypertensive emergencies. Lancet 1994; 344:1335.