Tuesday, January 15, 2019

Oxygen in acute CHF

Q: What is the pitfall of administrating excess oxygen to patients with acute decompensation of congestive heart failure (CHF)?



Answer: Although oxygen should be administrated to counter hypoxemia in patients with acute exacerbation of CHF, the excess of it may cause vasoconstriction and may cause counter-productive decrease in cardiac output. This again reinforce to treat oxygen as a drug.

#cardiology

#pharmacology



Reference:


Park JH, Balmain S, Berry C, et al. Potentially detrimental cardiovascular effects of oxygen in patients with chronic left ventricular systolic dysfunction. Heart 2010; 96:533.

Monday, January 14, 2019

Hyponatremia in hepatic cirrhosis

Q: Hyponatremia should be treated aggressively in hepatic cirrhosis patients who are not the candidates for liver transplant? (select one)

A) True
B) False


Answer: B

In contrast to hypokalemia, hyponatremia practically has no clinical effect on patients with liver cirrhosis unless until it is less than 120 mEq/L. 


It requires treatment only in 2 cases


1. If neurologic symptoms appear to be related to hyponatremia


2. A patient is going for a liver transplant. In such a case, sodium should be raised to 130 mEQ/L. Again, care should be taken to avoid very rapid correction due to the risk of osmotic demyelination syndrome (central pontine myelinolysis).


#hepatology

#electrolytes


References:


Angeli P, Wong F, Watson H, et al. Hyponatremia in cirrhosis: Results of a patient population survey. Hepatology 2006; 44:1535.

Sunday, January 13, 2019

measuring CSF pressure

Q: During lumbar puncture (LP) the accurate cerebro-spinal fluid (CSF) pressure is measured with a manometer in a patient lying flat in the lateral decubitus position with the legs? (select one) 

 A) extended 
 B) flexed


Answer: A

Although controversy persists about the clinical significance but flexing the legs during the LP may falsely elevate the CSF pressure. An LP can be performed with the patient in the prone, lateral recumbent or sitting upright. The lateral recumbent or prone positions provides the most accurate measurement of the opening pressure. In lateral recumbent position, initially patient remains in the fetal position with the neck, back, and limbs held in flexion. 


Once CSF begins to flow, the patient should be asked to slowly extend the legs. This allows the free flow of CSF within the subarachnoid space. A manometer then is placed over the hub of the needle and the opening pressure is measured.

Please refer to manuals for detailed proper positioning and technique.



#procedures
#neurology



References:

1. Rajagopal V, Lumsden DE. Best BETs from the Manchester Royal Infirmary. BET 4: does leg position alter cerebrospinal fluid opening pressure during lumbar puncture? Emerg Med J 2013; 30:771. 

2.Abel AS, Brace JR, McKinney AM, et al. Effect of patient positioning on cerebrospinal fluid opening pressure. J Neuroophthalmol 2014; 34:218.

Saturday, January 12, 2019

B-Blocker after Thyroid storm

Q: Beta-Blocker (BB) should be discontinued as soon as thyroid storm is clinically improved? (select one)

A) True
B) False


Answer: B

Although BB is used to control the acute symptoms of thyroid storm, it should be discontinued only after the thyroid function tests (TFTs) have returned to normal. This is due to the fact that BB, particularly Propranolol may continue to help in reducing the serum T3 levels.


#endocrine

#pharmacology 



References:


Cooper DS, Daniels GH, Ladenson PW, Ridgway EC. Hyperthyroxinemia in patients treated with high-dose propranolol. Am J Med 1982; 73:867.

Friday, January 11, 2019

Cough in extubation

Q: Despite passing weaning parameters, poor cough strength is a reliable indicator of failed extubation. What is an easy bedside method to test adequate cough strength in a patient who otherwise seems ready for extubation? 



Answer: After detaching endotracheal tube (ETT) from the ventilator circuit, an index card is held about 2 cm from the end of the ETT. A patient who is unable to moisten the card with few efforts of cough is more likely to fail extubation. 1

Extubation failure is well documented in patients who cannot cough on demand despite good weaning parameters. More appropriate method to test the cough strength is to insert a spirometer into the ventilator circuit. Strength of cough can be measured with peak expiratory flow (PEF) during the cough. PEF ≤60 L/min are five times more likely to fail extubation.



#ventilators

#pulmonary


References/further reading:


1. Khamiees M, Raju P, DeGirolamo A, et al. Predictors of extubation outcome in patients who have successfully completed a spontaneous breathing trial. Chest 2001; 120:1262. 


2. Beuret P, Roux C, Auclair A, et al. Interest of an objective evaluation of cough during weaning from mechanical ventilation. Intensive Care Med 2009; 35:1090. 

3. Thille AW, Boissier F, Ben Ghezala H, et al. Risk factors for and prediction by caregivers of extubation failure in ICU patients: a prospective study. Crit Care Med 2015; 43:613. 

4. Epstein SK. Putting it all together to predict extubation outcome. Intensive Care Med 2004; 30:1255. 

5. Smina M, Salam A, Khamiees M, et al. Cough peak flows and extubation outcomes. Chest 2003; 124:262. 

Thursday, January 10, 2019

Chest tube suction on expanded PTX

Q: 32 year old male is admitted to ICU after an episode of spontaneous pneumothorax (PTX). CXR normalized after insertion of chest tube. What is the danger of putting chest tube to a water seal device with suction? 



Answer: re-expansion pulmonary edema

Chest tube in patients with pneumothorax usually put connected to a water seal device. Application of suction should be applied only if there is no resolution of PTX, as there is a risk of re-expansion pulmonary edema.


#pulmonary

#procedure
#surgicalcriticalcare


Reference: 

 MacDuff A, Arnold A, Harvey J, BTS Pleural Disease Guideline Group. Management of spontaneous pneumothorax: British Thoracic Society Pleural Disease Guideline 2010. Thorax 2010; 65 Suppl 2:ii18.


Wednesday, January 9, 2019

DVT in burn patients

Q: Due to high risk of coagulopathy, need for frequent wound excisions, and ineffectiveness of subcutaneous (SQ) route secondary to fluid shifts - chemical deep venous thrombosis (DVT) prophylaxis should be deferred in the first week of treatment in patients with severe burn? (select one) 

A) True 
B) False 


Answer: B

Despite all challenges like a high risk of coagulopathy, need for frequent wound excisions, and possible ineffectiveness of SQ administration of chemical DVT prophylaxis secondary to fluid shifts, burn patients should not be treated differently from other ICU patients. 


The risk of DVT is higher in patients with more than 20 percent of total body surface area (TBSA) burn. 

#burn

#DVT



Reference:


Faucher LD, Conlon KM. Practice guidelines for deep venous thrombosis prophylaxis in burns. J Burn Care Res 2007; 28:661.

Tuesday, January 8, 2019

NAVA

Q: In neurally adjusted ventilatory assist ventilation (NAVA), electrical discharge from the diaphragm (EAdi) is detected by a catheter embedded in? 

A) Central Venous Catheter 
B) Naso-gastric tube 
C) Ventilator circuit 
D)Endo-tracheal tube (ETT) 
E) Cutaneous pacer


Answer: B

Neurally adjusted ventilatory assist ventilation (NAVA) is still an investigational mode of ventilation. It's working depends on the diaphragmatic excitation, technically known as 'electrical discharge from the diaphragm' (EAdi). The deflection above the set threshold is detected via a catheter embedded in a nasogastric tube to deliver a mechanical breath. 


NAVA is best utilized when patient-ventilator asynchrony becomes detrimental and cannot be fixed via more conventional modes of ventilation. The biggest hurdle in the use of NAVA is the requirement of spontaneously breathing patient. It cannot be used in a patient with decrease respiratory drive as in deep sedation.


#ventilator

#pulmonary


References:



1. Piquilloud L, Vignaux L, Bialais E, et al. Neurally adjusted ventilatory assist improves patient-ventilator interaction. Intensive Care Med 2011; 37:263. 

2. Schmidt M, Kindler F, Cecchini J, et al. Neurally adjusted ventilatory assist and proportional assist ventilation both improve patient-ventilator interaction. Crit Care 2015; 19:56. 

3. Demoule A, Clavel M, Rolland-Debord C, et al. Neurally adjusted ventilatory assist as an alternative to pressure support ventilation in adults: a French multicentre randomized trial. Intensive Care Med 2016; 42:1723.

Monday, January 7, 2019

CRP in pericarditis

Q: C-reactive protein (CRP) is a good marker to follow in resolution of acute pericarditis? (select one) 

 A) True 
B) False


Answer: A

Besides clinical symptoms, C-reactive protein (CRP) is an excellent marker to suggest resolution of acute pericarditis. If acute pericarditis does not get better with aspirin, colchicine or NSAIDs within 5-7 days, it suggests alternative cause other than viral or idiopathic. In such scenarios, checking CRP may be of help.


#cardiology
#laboratory-medicine


Reference:

Imazio M, Brucato A, Maestroni S, et al. Prevalence of C-reactive protein elevation and time course of normalization in acute pericarditis: implications for the diagnosis, therapy, and prognosis of pericarditis. Circulation 2011; 123:1092.

Sunday, January 6, 2019

Anti-rejection meds pericarditis

Q: Cyclosporine associated pericarditis is more common after which organ transplant? (select one) 

 A) Heart 
 B) Kidney


 Answer: A

Post transplant pericarditis is common and can occur due to variety of reasons. Renal transplant patients are more at risk due to development of uremia. Other leading causes are cytomegalovirus and anti-rejection medications. 


Among anti-rejection medications, Sirolimus tends to do pericarditis more in renal transplant patients, while cyclosporine associated pericarditis is more common in post heart transplant patients.


#trasnsplant

#pharmacology
#cardiology


References: 

1. Hastillo A, Thompson JA, Lower RR, et al. Cyclosporine-induced pericardial effusion after cardiac transplantation. Am J Cardiol 1987; 59:1220.

2. Sever MS, Steinmuller DR, Hayes JM, et al. Pericarditis following renal transplantation. Transplantation 1991; 51:1229.

Saturday, January 5, 2019

Diuretic induced hyponatremia

Q: Which of the diuretics tend to cause hyponatremia more?

A) Thiazide diuretics
B) Loop diuretics


Answer: A

Thiazide diuretic tends to cause hyponatremia due to their reduced diluting ability. This interferes with water excretion.This is a direct effect of reduced sodium chloride reabsorption without water in the distal tubule.


#nephrology

#lectrolytes


Reference:


Frenkel NJ, Vogt L, De Rooij SE, et al. Thiazide-induced hyponatraemia is associated with increased water intake and impaired urea-mediated water excretion at low plasma antidiuretic hormone and urine aquaporin-2. J Hypertens 2015; 33:627.

Friday, January 4, 2019

Hungry Bone Syndrome

Case: 62 year old male with End Stage Renal Disease (ESRD) is admitted to ICU after parathyroidectomy. All of the following electrolyte imbalances are expected except?

A) Hypocalcemia 

B) Hypophosphatemia 
C) Hypomagnesemia 
D) Hyperkalemia 
E) Hypernatremia


Answer:  E

The objective of the above question is to highlight the electrolyte imbalances in "Hungry Bone Syndrome" (HBS), a possible scenario after parathyroidectomy, particularly in ESRD patients. The hallmark of HBS is hypocalcemia (choice A) but other electrolyte imbalances may occur (choices B, C, D). ESRD patients are more prone to have hyponatremia due to volume-overload instead of hypernatremia (choice E).


#surgicalcriticalcare

#electrolyteimbalance
#nephrology


References:


1. Cruz DN, Perazella MA. Biochemical aberrations in a dialysis patient following parathyroidectomy. Am J Kidney Dis 1997; 29:759. 


2. Shpitz B, Korzets Z, Dinbar A, et al. Immediate postoperative management of parathyroidectomized hemodialysis patients. Dial Transplant 1986; 15:507.

Thursday, January 3, 2019

Preserving donor lung

Q: While inflating donor lungs with oxygen, all of the following are true except?

A) It preserves the integrity of pulmonary surfactant

B) It improves the epithelial fluid transport 
C) Lung inflation is limited to an airway pressure of 20 cm H2O
D) Inflation should be done with 100% FiO2
E) Trachea should be clamped after inflation


Answer: D

Inflation of lungs with oxygen during the ischemic time protects the lungs. All of the choices are correct except it requires only 30-50% of FiO2. In fact, 100% FiO2 can be injurious due to oxygen toxicity.



#transplantation

#pulmonary


References:


1. DeCampos KN, Keshavjee S, Liu M, Slutsky AS. Optimal inflation volume for hypothermic preservation of rat lungs. J Heart Lung Transplant 1998; 17:599. 


2. Kayano K, Toda K, Naka Y, Pinsky DJ. Identification of optimal conditions for lung graft storage with Euro-Collins solution by use of a rat orthotopic lung transplant model. Circulation 1999; 100:II257.

3.  Eberlein M, Reed RM, Permutt S, et al. Parameters of donor-recipient size mismatch and survival after bilateral lung transplantation. J Heart Lung Transplant 2012; 31:1207.

Wednesday, January 2, 2019

Propranolol in thyroid storm

Q: Why propranolol is a preferred Beta-blocker in thyroid storm? 

Answer: Propranolol is a preferred Beta-blocker in thyroid storm because it inhibits the type 1 deiodinase, which may help reduce serum T3 level, besides treating the symptoms. Also, it can be given orally, via nasogastric route or intravenous.

#endocrine

#pharmacology


Reference:


Cooper DS, Daniels GH, Ladenson PW, Ridgway EC. Hyperthyroxinemia in patients treated with high-dose propranolol. Am J Med 1982; 73:867.

Tuesday, January 1, 2019

MDMA overdose

Q: 23 year old male is admitted to ICU after attending all night "circuit party" on new year's eve. Intoxication with 3,4-methylenedioxymethamphetamine (MDMA) is highly suspected. Patient starts having seizures in ICU and required intubation for the protection of airway. Patient is found to be hyperthermic at 41°C. Serum sodium is reported as 114 mEq/dL. All of the following can be administrated except?

A)  Benzodiazepines 

B) Activated charcoal 
C) Phenytoin 
D) 3% (hypertonic) saline 
E) Active external cooling


Answer:  C

MDMA, popularly known as 'Ecstasy' is a dangerous drug. It is a common drug used for "raves" or "circuit parties". Benzodiazepine is the mainstay of treatment.  Following drugs should be avoided, though clinicians may tend to use them.

  • haloperidol 
  • phenytoin 
  • beta-blockers 
  • antipyretics
Haldol may decrease the seizure threshold, interfere with heat dissipation, as well as may prolong the QTc interval. Pure beta-blockers may cause unopposed alpha-adrenergic stimulation. Seizure in MDMA intoxication is mostly due to hyponatremia and do not respond to phenytoin. Similarly, hyperthermia does not respond to antipyretics and may require active cooling.

#toxicology

#electrolyteimbalance
#neurology


References:


Kalant H. The pharmacology and toxicology of "ecstasy" (MDMA) and related drugs. CMAJ 2001; 165:917. 


Armenian P, Mamantov TM, Tsutaoka BT, et al. Multiple MDMA (Ecstasy) overdoses at a rave event: a case series. J Intensive Care Med 2013; 28:252.