Q: Which drug used during cardio-pulmonary bypass (CPB) may cause continuous diuresis in immediate post-CABG patients?

Answer:  Mannitol

Mannitol is commonly used in the circuit prime of a heart lung machine during cardiopulmonary bypass. The presence of mannitol preserves renal function during periods of low blood flow and pressure, while the patient is on bypass.

During cardiopulmonary bypass in adult patients, priming fluid which usually contains 10 g of mannitol may causes a transient diuresis during the bypass period. However, in some instances 20 to 30 g of mannitol may be used which may causes diuresis for 3 to 4 hours during the post bypass period. In some cases, the diuretic effect of mannitol may last for up to 12 hours after on pump CABG, which may require monitored IVF administrations. 

Q: How Cisatracurium degradation is related to body temperature?

Answer: Cisatracurium is degraded by Hofmann elimination and ester hydrolysis in plasma. Hofmann elimination is a temperature- and plasma pH-dependent process. An increase in body pH and temperature favors the elimination process.

Trivia: Cisatracurium was marketed as Nimbex. "Nimbex" was derived from inserting an "i" to word "Nmbex," which stood for excellent Neuromuscular blocker.

Train of Four (TOF)

Link: http://youtu.be/kNLe5hLSFz8

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Q: What is the best way to avoid damage to recurrent laryngeal nerve during intubation?

Answer: One of the major reason of nerve damage during intubation is over-inflated and mal-positioned ETT cuff. The anterior branch of the recurrent laryngeal nerve can be compressed between the endotracheal tube's cuff and the lamina of the thyroid cartilage when the cuff is inflated. If the cuff of endotracheal tube is positioned at more than 15 mm below the vocal cords, it can avoid expansion of the cuff in the larynx.

Reference:

Benumof JL. Airway Management: Principles and Practice. St. Louis: Mosby; 1996. p. 868.

Q: 22 year old male is admitted to ICU after cocaine overdose. What one simple maneuver during physical exam is often missed?

Answer: Examination of nares

Patients with cocaine toxicity should have their nares examine to remove residual cocaine from nares.

Q: Is it absolutely necessary to have ABG (Arterial Blood Gas) for the diagnosis of DKA (diabetic ketoacidosis)?






Answer: No


Biochemically, DKA is defined and highly suspected along with clinical history as


• an increase in the serum ketones greater than 5 mEq/L,
• a blood glucose leve at least greater than 250 mg/dL
• a blood pH less than 7.3.
•  ketonuria
•  a serum bicarbonate level of 18 mEq/L or less 
•  increased anion gap,
• increased serum osmolarity and
•  increased serum uric acid


All of the above does not require ABG. Studies have shown that coefficients of variation for arterial and venous samples are similar for pH, serum bicarbonate, and potassium.

Reference:

Herrington WG, Nye HJ, Hammersley MS, Watkinson PJ. Are arterial and venous samples clinically equivalent for the estimation of pH, serum bicarbonate and potassium concentration in critically ill patients?. Diabet Med. Jan 2012;29(1):32-5

Q: Following may happen in pure Respiratory alkalosis (Hypocapnia) except

A) Hypokalemia

B) Hypercalcemia

C) Hypophosphatemia

D) Hyponatremia

E) Hypochloremia

Answer: B 

Clinical Significance:: Alkalosis causes hypokalemia and hypophophatemia due to increased intracellular shifts. But hypocalcemia is due to increased binding of calcium to serum albumin due to the change in PH. Most of the symptoms present in respiratory alkalosis are due to hypocalcemia. Alkalosis also causes hyponatremia and hypochloremia.

Q: Patient with history of hypertension and anxiety presented to the hospital with tachypnea.  Patient 

sodium  140meq/l,
potassium 3meq/l, 
chloride  94meq/l and 
HCO₃  34.  

On arterial blood gas, 

ph 7.67
pCO2 30.  

What is the acid base disturbance?

A)  Respiratory alkalosis

B)   Metabolic  alkalosis

C)  Respiratory and metabolic alkalosis

D)  Hyperchloremic non-anion gap metabolic acidosis

Answer: C

Rationale: Patient HCO₃ is high suggestive of metabolic alkalosis.

Patient expected CO₂ should be (pCO₂=HCO₃x0.9+9;34x0.9+9=39.6); 
CO₂ is 30, which is lower than expected pCO₂,
suggestive of mixed respiratory and metabolic alkalosis.

Question: Mortality rate in patients with community acquired pneumonia is adversly affected by drug resistent pneumococcal only when minimum inhibitory concenteration (MIC) is greater than

A. > 0.5
B. > 2
C. > 4
D. > 1


Answer: C

Older age and underlying disease remain the most important factors influencing death from pneumococcal pneumonia. Mortality was not elevated in most infections with beta-lactam-resistant pneumococci.

Reference: 

Felkin D, Schuchat A, et al. Mortality from invasive pneumococcal pneumonia in the era of antibiotic resistance, 1995-1997. Am J Public Health 2000; 90: 223-229

Q: Which finding in CBC is highly suggestive of Adrenal crisis? (Select one)
A) Neutrophilia
B) Eosinophilia
C) Thrombocytopenia
D) Neutropenia
E) Polycythemia



Answer: Eosinophilia

Hyponatremia, hyperkalemia, metabolic acidosis, and hypoglycemia may be present along with anemia and lymphocytosis, but eosinophilia with above serum chemistry findings is highly suggestive of Adrenal Crisis.

Q: Assuming patient is stable and conservative/observation approach is taking for pneumothorax noticed on chest X-ray, What is the resorption rate?


Answer: Automated resorption rate of pneumothorax is estimated between 1.25% and 2.2% the volume of the cavity per day.



Reference:

MacDuff A, Arnold A, Harvey J; BTS Pleural Disease Guideline Group (December 2010). "Management of spontaneous pneumothorax: British Thoracic Society pleural disease guideline 2010". Thorax 65 (8): ii18–ii31

Q: Which of the following is the risk factor for post-extubation larngeal edema?

A) Male gender
B) Prolonged intubation (>14 days)
C) Undersized endotracheal tubes
D) Self extubation
E) Cuff leak less than 50%


Answer: D

Some of the risk factors of post-extubation laryngeal edema are traumatic intubation, female gender, prolonged intubation of >7 days, oversized endotracheal tubes, self extubation and a leak of less than 30% of the administered tidal volume upon deflation of the endotracheal tube cuff.

Q: Though debatable but one treatment for symptomatic vasospasm after Subarachnoid Hemorrhage (SAH) is "triple H therapy" (hypertension, hypervolemia, and hemodilution). It is recommended to 'float swan' (insertion of Pulmonary Artery Catheter) to guide volume expansion and inotropic or vasopressor therapy. What is the recommended "wedge pressure" (pulmonary artery occlusion pressure) is such cases?


Answer:  Pulmonary artery wedge pressure (PAWP) should be maintained at 14-20 mm Hg. If 'swan' is not inserted than Central venous pressure (CVP) should be maintained at least at 10-12 mm Hg. 

Treatment for symptomatic vasospasm after Subarachnoid Hemorrhage has traditionally involved the application of hypertension, hypervolemia, and hemodilution, or triple H therapy. Though, the efficacy of triple H therapy remains subject to debate. Aggressive hypertensive therapy with inotropes and vasopressors can be initiated. Hypervolemia is  achieved by using pRBCs, isotonic crystalloid, and colloid. Hemodilution is targeted to maintain the hematocrit at 30-35% in order to optimize blood viscosity.


Reference:

Dankbaar JW, Slooter AJ, Rinkel GJ, Schaaf IC. Effect of different components of triple-H therapy on cerebral perfusion in patients with aneurysmal subarachnoid haemorrhage: a systematic review. Crit Care. 2010;14(1):R23. 

Q: 74 year old nursing home resident male is diagnosed with liver abcess which is about 4 cm in size. Appropriate antibiotics have been started. Percutaneous catheter is placed for drainage. How long catheter should stay in place?


Answer: 

Percutaneous drainage is usually the first line of management, particularly in patients with low funtional status. Surgical intervention is required only for cysts greater than 5 cm, ruptured cysts, or multiloculated cysts. The catheter is flushed daily until output is less than 10 cc/day or cavity is demonstrated to be collapsed by serial imagings.

Q: What one preventive masure may help to reduce the hazard of fire during tracheostomy insertion due to electrocautery?


Answer: Maintaing the integrality of ETT cuff

ETT cuff serves as a barrier to prevent oxygen leaking out from the trachea to be exposed to the sparks of electrocautery while the procedure is under way, and thus it plays a significant role in the avoidance of airway fire induced by electrocautery. Moreover, lowering of the FiO2 also may help.



Reference:

Wu CC, Shen CH, Ho WM. -  Endotracheal tube fire induced by electrocautery during tracheostomy--a case report. -  Acta Anaesthesiol Sin. 2002 Dec;40(4):209-13.

Q: Use of esophageal thermal probe is not contraindicated in a ventilated patient but which one concern should be kept in mind regarding use of esophageal thermal probe in ventilated patient?


Answer: Cooling by ventilated air if probe is not at right position.

The esophagus is close to the trachea and bronchii at the upper border of the inferior mediastinum, so if esophageal thermal probe is sitting in this region it may lead to cooling of this region especially during high ventilation rates. Thus, it is possible that in this region, the measured temperature may not necessarily be indicative of the myocardial or blood temperature. The esophagus is closest to the myocardium at approximately T8.  Therefore, level of T8/T9 retains its advantage as a site distal to the tracheal bifurcation and close to the left ventricle and aorta, and best suited for thermal monitoring.



References:

1. CAPUTA, M. Thermal gradients in the oesophagus of man during exercise and passive warming. J. Therm. Biol. 5: 249-251, 1980.

2. LINNARSSON, D., T. RIBBE, AND B. HALLEN. Oesophageal probe for heart and temperature monitoring during anaesthesia. Med. Biol. Eng. Comput. 20: 390-392, 1982. 

Q: What added benefit high flow nasal cannula oxygen provides beside relief of hypoxemia?

Answer: High flow oxygen (HFO) therapy via high flow nasal cannula (HFNC) serves many purposes. It is a very effective therapy in preventing invasive ventilation while clinicians work on treating underling causes of impending respiratory failure. It not only improve oxygenation or decrease the work of breathing, but also decreases atelectasis and counteracts intrinsic PEEP. In HFNC, gas inlet flow prevents secondary room-air entrainment, provides anatomic oxygen reservoirs using nasopharynx and oropharynx and washes out airway dead spaces.

References:

1. Parke R, McGuinness S, Eccleston M. Nasal high-flow therapy delivers low level positive airway pressure. Br J Anaesth. 2009;103(6):886-90.

2. Kernick J, Magarey J. What is the evidence for the use of high flow nasal cannula oxygen in adult patients admitted to critical care units? A systematic review. Aust Crit Care. 2010;23(2):53-70. 

Q: Which muscles are prone to get more affected in Critical illness polyneuropathy (CIP) and critical illness myopathy (CIM)?

Answer: The hip and shoulder muscles

Critical illness polyneuropathy (CIP) and critical illness myopathy (CIM) is a clinical diagnosis though some work up may assist to confirm it. Clinical clues are critically ill patients  who are immobilized and have progressive, generalized, symmetric muscle weakness. Setting of CIP/CIM may delay extubation time by 1-2 weeks.

Reference:

Johnson, KL (Apr–Jun 2007). "Neuromuscular complications in the intensive care unit: critical illness polyneuromyopathy.". AACN Advanced Critical Care 18 (2): 167–80; quiz 181–2.

Hermans, Greet; De Jonghe, Bernard; Bruyninckx, Frans; Berghe, Greet (2008). "Clinical review: Critical illness polyneuropathy and myopathy". Critical Care 12 (6): 238.

Q: What unique advantage Etomidate has to be use in intubation in traumatic brain injury patients?

Answer:

Lately, Etomidate has earned significant negative reviews for its use in ICU mostly because of its potential to cause transient adrenal suppression, even with a single dose. But Etomidate has an unique characteristics for patients with traumatic brain injury, as it decreases intracranial pressure without dropping normal arterial pressure.

Q: What is "Telltale triangle sign"?

Answer:   

"Telltale triangle sign" is a triangular air pocket between 3 loops of bowel. It signifies pneumoperitoneum.

Gas explosion

A complication of colonoscopy

(From American Society of Gastrointestinal Endoscopy Guidelines)

"Explosive complications of colonoscopy are rare, but they have serious consequences. A 2007 review reported 9 cases, each resulting in colonic perforation and, in one case, death.Gas explosion can occur when combustible levels of hydrogen or methane gas are present in the colonic lumen, oxygen is present, and electrosurgical energy is used (eg, electrocautery or argon plasma coagulation). Suspected risk factors are use of nonabsorbable or incompletely absorbable carbohydrate preparations, such as mannitol, lactulose, or sorbitol, and incomplete colonic cleansing either because a sigmoidoscopy preparation was used (eg, enemas) or because the result of a colonoscopic purge preparation was inadequate. Some authors have advocated use of carbon dioxide during colonoscopy as a preventive measure."                             

Reference: 

GASTROINTESTINAL ENDOSCOPY Volume 74, No. 4 : 2011

http://www.asge.org/assets/0/71542/71544/56321364-c4d8-4742-8158-55b6bef2a568.pdf

Q: What is the advantage of rectal aspirin over oral aspirin?

Answer: Faster systemic absorption with suppositories

Aspirin given by rectal suppository is absorbed by the inferior and middle hemorrhoidal veins that eventually drain into the inferior vena cava, avoiding presystemic metabolism through the liver. This will result in early aspirin levels.

Clinical significance: In CVA or acute MI patients where oral or chewable aspirin is not possible due to fear of aspiration, rectal route is as effective, rather quicker in action.

Reference: Nakayasu H, Maeda M, Soda T, et al. The antiplatelet aggregation effects of aspirin suppositories. Cerebrovasc Dis. 2003; 16:31–5.

Q: 37 year old male with PMH of hypertension is admitted to ICU with chest pain. After angiogram, has been diagnosed with Prinzmetal's angina. Which one medicine should be prescribed with caution for his hypertension?

Answer: Beta-Blocker

In Prinzmetal's angina beta blockers can cause further spasm making it worse. Alike in cocaine overdose, beta-blockers leave the alpha1 receptors available for binding by various endogenous hormones.

Also, aspirin is not indicated with clean coronaries. It is postulated that aspirin can effect the vasodilator mechanisms in the endothelium since it is an inhibitor of prostacyclin production as well as nitric oxide.

Cardiac Sarcoidosis

-A case report -

"47-year-old male presented to the cardiology out-patient department (OPD) with shortness of breath and chest discomfort on exertion since one week. Chest discomfort was related to exertion and relieved by rest. He has hypertension and hypertriglyceridemia controlled well on oral Amlodipine and Fenofibrate since one year. He does not smoke, drink alcohol, or use any recreational drugs. The patient gives past history of cutaneous sarcoidosis which was diagnosed by biopsy of the lesion one year back. He was evaluated for systemic sarcoidosis and was found to have hilar lymph nodes by computed axial tomography of chest and was advised for a follow-up CT after 6 months. The follow-up CT scan showed improvement and the patient was asymptomatic.......Three months after this evaluation, he presented to our OPD with the present symptoms. ......At the time of presentation his electrocardiography (ECG) revealed sinus rhythm with a rate of 62 per minute with prolonged PR interval and right bundle branch block (RBBB). Cardiac enzymes were normal......His stress test showed poor chronotropic response and rate dependent 2 : 1 atrioventricular (AV) block occurring during the exercise test.......coronary angiography next day which showed normal coronaries.........."

EKG showing complete heart block. Ventricular rate is 25 per minute, QRS complex is very wide and there is AV dissociation.

Read full case report, EKGs, CXR and discussion here


Reference: Nagham Saeed Jafar and col., Rapidly Progressive Atrioventricular Block in a Patient with Sarcoidosis - Case Reports in Cardiology- Volume 2014 (2014)

Q:  What is another rule of thumb in evaluating burn area besides 'rule of 9'?

Answer: The Rule-of-Palms

The patient's palm can serve as a guide roughly equivalent to 1% of the total body surface area (TBSA).

Reference:

Wen-bo Sheng, Ding Zeng, Yan Wan, Li Yao, Hong-tai Tang - BurnCalc assessment study of computer-aided individual three-dimensional burn area calculation - J Transl Med. 2014; 12(1): 242. - Published online Sep 10, 2014.

Q:  What is "rule of 7" when writing orders for hemodialysis (HD)?

Answer: 

The "Rule of 7" is the rule of thumb for the choice of Potassium(K) bath concentration while writing orders for HD.

The patient's K plus the dialysate bath K should equal approximately 7.

For example, if somebody presents with a K of 5.1, put them on a 2 K bath; if they present with a K of 3.2, put them on a 4 K bath. The lowest K bath usually used is 1 K bath and the highest K bath is usually 4K bath - but these are used very judiciously.

Q:  52 year old male with ESRD had out of hospital witnessed cardiac arrest. Patient survived CPR and has been started on hypothermia protocol in ER. Patient is now hypertensive. Potassium is under normal range. Cardiology requests to perform dialysis before angiogram. What is your concern performing hemodialysis (HD)?

Answer: Most HD machines warm blood before returning in to the patient. With most machines, the warmer only goes as low as 35 degrees Celsius. In other words, dialysis can inadvertently warm the patient up to this temperature (from the target temp of 32 degrees, per the hypothermia protocol). Fortunately, CRRT machines do have adjustable temp settings that goes down to 32 degrees, so that might be a better alternative. If HD is absolutely needed, dialysate should be cooled down to 32 - 34°C. 

Q:  37 year old female with established diagnosis of antiphospholipid syndrome presented with Crisis (catastrophic stage) with clinical signs of generalized thrombosis. Patient has previously failed treatment with high dose steroid. Patient was doing well on warfarin but due to her diet change, INR on presentation is 2.0 instead of target of 2.5 to 3. What are other options at this stage?

Answer: Plasmapheresis or IVIG - or combination of both

Catastrophic Antiphospholipid Syndrome (CAPS) is a subset of patients who develop end-organ damage as a result of thrombic microangiopathy. Treatment includes anticoagulants, steroids, and possibly IVIG and therapeutic plasma exchange. Albumin is advocated by some experts for use in plasma exchange as traditional FFP contains clotting factors, cytokines, and complement activation products which may worsen the "thrombotic storm".

Q:  What are the few main culprits causing posterior reversible encephalopathy syndrome (PRES) ?

Answer: Posterior reversible encephalopathy syndrome (PRES) is a syndrome characterized by headache, confusion, seizures and visual loss. It is very under diagnosed entity and require MRI for definite diagnosis.

• Severe hypertension
• Eclampsia
• Renal failure
• Hypomagnesemia
• Lupus