Saturday, March 31, 2012

Q: 70 year old chinese male with history of Atrial fibrillation and on warfarin presented with acute symptoms of stroke. Patient's family reports that patient is very health conscious and takes his warfarin faithfully. Actually, he recently brought some traditional medicines from china. What could be the probable culprit?

Answer: Ginseng

In one double-blind, four-week trial, 20 healthy volunteers received warfarin, 5 mg, daily for three days during week one and week four. Beginning in week two, 12 subjects took 2 gram of powdered ginseng in capsules, while the other eight volunteers received placebo capsules.

After two weeks, daily doses of ginseng significantly reduced the blood levels and the anticoagulant effects of warfarin. Compared with the placebo group, the ginseng group had significantly reduced INR and peak plasma warfarin level.

Brief Communication: American Ginseng Reduces Warfarin's Effect in Healthy Patients - A Randomized, Controlled Trial - Annals of Internal Medicine, July 6, 2004 vol. 141 no. 1 23-27

Friday, March 30, 2012

Q: 32 year old otherwise healthy male with 2 weeks history of sinusitis presented with siezure. ER physician called you while he sent patient to CT scan. What would be your primary concern and line of action? 

Answer: Neurological symptoms after prolong bout of sinusitis is highly suggestive of Subdural empyema.

Subdural empyema is a neurosurgical emergency and beside instituting antibiotics and anti-seizure meds, it would be appropriate to ask neurosurgical service to review CT scan while patient is in neuroradiology department. It has a tendency to spread rapidly through the subdural space.

Thursday, March 29, 2012

On management of empyma thoracis

The administration of intrapleural streptokinase is common in the management of loculated empyema thoracis. Due to its immunogenicity and its inability to reduce pus viscosity, tissue plasminogen activator (tPA) has been sugggested as better alternative to facilitate drainage of empyema thoracis. tPA induces fibrinolysis by preferentially activating plasminogen bound to fibrin and is less immunogenic.

Another alternative is to use recombinant human deoxyribonuclease (DNase) which is known to reduce pus viscosity by fragmenting free uncoiled deoxyribonucleic acid found in pus. 

Interestingly, atleast one randomized trial has shown that combination of tPA and DNase is superior but DNase or tPA alone are ineffective. Moreover, DNase alone appears to be associated with an increased frequency of surgery or death. 

Rahman NM, Maskell N, Davies CW, West A, Teoh R, Arnold A, et al. Primary result of the second multicentre intrapleural sepsis (MIST2) trial; randomized trial of intrapleural tPA and DNase in pleural infection. Thorax 2009;64:A1

Wednesday, March 28, 2012

Q: Is Milrinone a venodilator or an arterial dilator? 


Milrinone has minimal venodilation effect. 
In reality, its a pure arterial dilator.

Tuesday, March 27, 2012

Octreotide in hepatorenal syndrome

Octreotide may be used in combination with midodrine and albumin  to minimize peripheral vasodilation in the hepatorenal syndrome. In return, by increasing systemic vascular resistance, shunting of blood get reduced and it improves renal perfusion. Study has showed that treatment with octreotide, midodrine, and albumin were independently associated with improved survival. Also, Renal function was significantly improved at 1 month.

Skagen C, Einstein M, Lucey MR, Said A (Feb 2009). "Combination Treatment With Octreotide, Midodrine, and Albumin Improves Survival in Patients With Type 1 and Type 2 Hepatorenal Syndrome.". J Clin Gastroenterol. 43 (7): 680–5., Link:

Sunday, March 25, 2012

Q: What is D-Lactic Acidosis? 

 Answer: D-lactate is not a result of inadequate human metabolism, rather it is a byproduct of bacterial metabolism. It accumulates in patients with short-gut syndrome, in patients with a history of gastric bypass or small-bowel resection. 

 Human body metabolism produced only L-Lactate. L-lactate is the reported measured level.

Saturday, March 24, 2012

Q: Sotalol 

 A) prolongs the PR interval 
 B) prolongs the QT interval 
 C) is a non-selective β blocker 
 D) may increase risk of death with decreased ejection fraction. 
 E) All of the above 

Answer: E 

 Sotalol is a non-selective competitive β-adrenergic receptor blocker that also exhibits Class III antiarrhythmic properties by its inhibition of potassium channels. 

 Though it can be use to treat hypertension, it is mostly used to treat ventricular tachycardias and atrial fibrillation. 

 Some evidence suggests that sotalol should be avoided in the setting of decreased ejection fraction due to an increased risk of death.

Friday, March 23, 2012

Q: Prune juice is frequently use in medical settings for constipation. Why it should be use with caution in ICU?

Answer: Prune juice should be use with caution in renal patients due to its high potassium content. 

6 oz. of prune juice contains 528 mg of potassium - or  5 prunes contain 313 mg of potassium.

Thursday, March 22, 2012

Q: House staff  injured himself while performing central line with needle stick. Patient is known as Hepatitis C positive. What are his chances of contracting disease?

Answer: 1.5 - 2.0 %
As expected chances are high if puncture wound is deep.
See full Needle injury protocol here

Wednesday, March 21, 2012

Q: What organism is most frequently involved in vertebral osteomyelitis? What is the antibiotic of choice for this organism? (choose one)

A- Pseudomonas aeruginosa
B- Klebsiella
C- Bacteroides fragilis
D- Staphylococcus aureus
E- E.Coli

Answer: D

The most common microorganism in vertebral osteomyelitis is Staphylococcus aureus, followed by E. Coli. The antibiotic of choice for vertebral osteomyelitis (without implant) is beta-lactam at high dose (e.g., nafcillin or oxacillin 2 g IV every 6 hours or cefazolin 1-2 g IV every 8 hours).

Tuesday, March 20, 2012

Q: How Methylene blue worked in Nor-epinephrine refractory vasoplegia? 

 Answer: Via inhibition of guanylate cyclase 

 Refractory vasoplegia reflect a dysregulation of nitric oxide synthesis and vascular smooth muscle cell guanylate cyclase activation. Release of proinflammatory mediators may act through the induction of the final commonpathway of nitric oxide, which is the activation of the guanylate cyclase, leading to vasodilation. Hyporesponsiveness to norepinephrine is due to the activation of the soluble guanylate cyclase.

Dose is 2 mg/kg administered intravenously over 20 minutes for one time. 

Monday, March 19, 2012

Q: Is ACT (Activated Coagulation Time) and PTT (Partial Thromboplastin Time) are interchangeable during Heparin infusion? - Yes or No

Answer: No 

 During Heparin infusion, ACT and PTT monitoring are not interchangeable. They have very poor correlation. ACT and PTT results should be followed independently. It is better to determine patient's heparin anticoagulant requirement, stabilize him/her, and follow one monitoring tool.

The ACT is measured in seconds - the longer the time blood takes to clot, the higher the degree of clotting inhibition.

PTT has more complex way to perform - The blood is spun in a centrifuge, which separates plasma from the cells. Calcium and activating substances are added to the plasma to start the intrinsic pathway of the coagulation cascade. PTT is the time it takes for a clot to form, measured in seconds.

Sunday, March 18, 2012

Q: Describe 3 contraindications for application of Lithium based Cardiac output?

Answer: Measurement of CO by lithium dilution is based on the same principles as the thermodilution techniques. Isotonic lithium chloride is injected as a bolus. It mixes with the venous blood as it travels through the right heart, pulmonary circulation, left heart, and the aorta. The concentration-time curve of the indicator is, in contrast to the thermodilution methods, routinely generated in a peripheral artery (A-line) by the use of an ion-selective electrode.

It is contra-indicated in  
  • patients receiving lithium therapy
  • patients who are less than 40 kg in weight and
  • patients in the first trimester of pregnancy

Saturday, March 17, 2012

Back to basics

Q: What is the normal stroke volume in a normal healthy 70 Kg man?

Answer: About 70 ml

The difference between end-diastolic volume (EDV) and end-systolic volumes (ESV) is the stroke volume, the volume of blood ejected with each heart beat.

Friday, March 16, 2012

Q: What is the difference between Indium Scan and Gallium scan in localizing infection?

Answer: The indium scan is a procedure in which WBCs (neutrophils) are removed from the patient, tagged with the radioisotope Indium-111, and then injected back into the patient. The tagged leukocytes subsequently enhance areas of relatively new infection, where live neutrophils are still rapidly and actively localizing.

Gallium scan has advantage over the indium scan because gallium binds to neutrophil membranes, even after neutrophil death. This makes gallium more broadly sensitive, localizing to other sources of fever, such as chronic infections and tumors.

Thursday, March 15, 2012

Wednesday, March 14, 2012

Q: Why Daptomycin is not a good choice to treat pulmonary infections?

A: Daptomycin binds to pulmonary surfactant, and therefore is not a good choice in the treatment of pulmonary infections, due to minimal free drug concentrations available in pulmonary secretions.

Tuesday, March 13, 2012

Q: How Biapenem is different than other Carbapenems?

A: Biapenem is more stable than imipenem, meropenem and panipenem to hydrolysis by human renal dihydropeptidase-I (DHP-I), and therefore does not require the coadministration of a DHP-I inhibitor.

Monday, March 12, 2012

Sinusitis in intubated patients

Sinusitis is a well recognised but insufficiently understood complication of critical illness. It has been linked to nasotracheal intubation, but its occurrence after orotracheal intubation is less clear. We studied the incidence of sinusitis in patients with fever of unknown origin (FUO) in our intensive care unit with the aim of establishing a protocol that would be applicable in everyday clinical practice.

Sinus X-rays (SXRs) were performed in all patients with fever for which an initial screening (physical examination, microbiological cultures and chest X-ray) revealed no obvious cause. All patients were followed with a predefined protocol, including antral drainage in all patients with abnormal or equivocal results on their SXR.

Initial screening revealed probable causes of fever in 153 of 351 patients (43.6%). SXRs were taken in the other 198 patients (56.4%); 129 had obvious or equivocal abnormalities. Sinus drainage revealed purulent material and positive cultures (predominantly Pseudomonas and Klebsiella species) in 84 patients. Final diagnosis for the cause of fever in all 351 patients based on X-ray results, microbiological cultures, and clinical response to sinus drainage indicated sinusitis as the sole cause of fever in 57 (16.2%) and as contributing factor in 48 (13.8%) patients with FUO. This will underestimate the actual incidence because SXR and drainage were not performed in all patients.

Physicians treating critically ill patients should be aware of the high risk of sinusitis and take appropriate preventive measures, including the removal of nasogastric tubes in patients requiring long-term mechanical ventilation. Routine investigation of FUO should include computed tomography scan, SXR or sinus ultrasonography, and drainage should be performed if any abnormalities are found.

Hospital-acquired sinusitis is a common cause of fever of unknown origin in orotracheally intubated critically ill patients - Critical Care 2005, 9:R583-R590

Sunday, March 11, 2012

Q: Describe 3 side effects of quetiapine (seroquel) which may be significant in ICU?


1. Swelling of the sinuses or pharynx
3. lower seizure threshold

Saturday, March 10, 2012

Washout gradient of Troponin in myocardial reperfusion

Myocardial reperfusion, (spontaneous or via lytics or PCI), affect the kinetics of troponin. Patients with ST-segment elevation myocardial infarction who achieve an effective reperfusion have a faster return to normal – called ‘‘wash-out phenomenon’’. The ratio between the concentrations at these two points can be used to discriminate between successful and unsuccessful reperfusion. In general, the greater the ratio (at least 5), the more likely it is that reperfusion has occurred.

Friday, March 9, 2012

Thursday, March 8, 2012

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 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.

Wednesday, March 7, 2012

Q: What is an appropriate way of estimating upper airway edema before extubation (cuff leak)?

Answer: A volume less than 10–12% of delivered tidal volume implies probable upper airway edema. The average difference between inspiratory and expiratory volume after cuff deflation, recorded for at least six consecutive breaths should be determined.

Reference: Tracheal extubation - Contin Educ Anaesth Crit Care Pain (2008) 8 (6): 214-220.

Tuesday, March 6, 2012

Brachial artery embolus mimicking acute stroke

 Interesting case report: (see reference below)

"An 85-year-old woman presented to an emergency department with acute onset of right upper extremity pain and weakness. She denied sitting with her arm propped up or falling asleep in an unusual position. Her medical history included paroxysmal atrial fibrillation, hypertension, dyslipidemia, congestive heart failure, and coronary artery disease. The patient was not anticoagulated because of a recent gastrointestinal bleeding episode.
The emergency department physician diagnosed acute stroke and requested a telemedicine consultation. The patient's blood pressure was 160/70 mm Hg, and a rhythm strip demonstrated normal sinus rhythm at 80 beats per minute. On neurologic examination, the right upper extremity strength revealed no effort against gravity with some preserved strength in wrist and finger extension. The patient could not localize touch on the right arm. Findings from the remainder of the neurologic examination, including speech and language, cranial nerves, coordination, and right lower extremity strength and sensation, were normal. Reflexes and plantar responses were not tested as part of the telemedicine stroke examination in this patient. A CT scan of the brain showed normal results.
Because pain was a prominent feature of the presentation, palpation of the right upper extremity for pulses was suggested to the emergency department physician..........." 

Read full reporl here. 

E-Pearl: Brachial artery embolus mimicking acute stroke -Neurology May 3, 2011 vol. 76 no. 18 e86-e87

Monday, March 5, 2012

A prognostic marker in SAH?


Copeptin has been proposed as a prognostic marker in acute illness. This study investigated the ability of copeptin to predict the disease outcome and cerebrovasospasm in the patients with aneurysmal subarachnoid hemorrhage.

In this retrospective study, 303 consecutive patients were included. Upon admission, plasma copeptin levels were measured by enzyme-linked immunosorbent assay. The end points were mortality after 1 year, in-hospital mortality, cerebrovasospasm and poor functional outcome (Glasgow Outcome Scale score of 1-3) after 1 year.


Upon admission, plasma copeptin level in patients was statistically significantly higher than that in healthy controls. A multivariate analysis showed that plasma copeptin level was an independent predictor of poor functional outcome and mortality after 1 year, in-hospital mortality and cerebrovasospasm. A receiver operating characteristic curve showed that plasma copeptin level on admission predicted poor functional outcome and mortality after 1 year, in-hospital mortality and cerebrovasospasm of patients statistically significantly. The area under curve of the copeptin concentration was similar to those of World Federation of Neurological Surgeons (WFNS) score and modified Fisher score for the prediction of poor functional outcome and mortality after 1 year, and in-hospital mortality, but not for the prediction of cerebrovasospasm. In a combined logistic-regression model, copeptin improved the area under curve of WFNS score and modified Fisher score for the prediction of poor functional outcome after 1 year, but not for the prediction of mortality after 1 year, in-hospital mortality, and cerebrovasospasm.


Copeptin level is a useful, complementary tool to predict functional outcome and mortality after aneurysmal subarachnoid hemorrhage.

Detection of copeptin in peripheral blood of patients with aneurysmal subarachnoid hemorrhageCritical Care 2011, 15:R288

Sunday, March 4, 2012

Propofol induced Myoclonus

Myoclonus is an uncommon side effect of propofol. Also opisthotonus, refractory dystonia, ataxia, seizures, delayed-onset seizures and seizure-like phenomena have been described from propofol. 
On discontinuation most neurologic complications associated with propofol resolve spontaneously but some literature exits on neurological sequelae that occurred after the withdrawal of propofol infusion persisting upto 18 days despite antiepileptic treatment.
Several possible mechanisms have been proposed but still the actual etiology is not well understood.
This is important to know that propofol has very short half life but it has a delayed terminal elimination half-life hence, significant concentrations of propofol may persist for days within the nervous system. 

Saturday, March 3, 2012

Geneva score for PE

Variable Score
60–79 years 1
80+ years 2
Previous venous thromboembolism
Previous DVT or PE 2
Previous surgery
Recent surgery within 4 weeks 3
Heart rate
Heart rate >100 beats per minute 1
PaCO2 (partial pressure of CO2 in arterial blood)
<35mmHg 2
35-39mmHg 1
PaO2 (partial pressure of O2 in arterial blood)
<49mmHg 4
49-59mmHg 3
60-71mmHg 2
72-82mmHg 1
Chest X-ray findings
Band atelectasis 1
Elevation of hemidiaphragm 1

The score obtained relates to the probability of the patient having had a pulmonary embolism (the lower the score, the lower the probability):
  • less than 5 points indicates a low probability of PE
  • 5 - 8 points indicates a moderate probability of PE
  • More than 8 points indicates a high probability of PE

Friday, March 2, 2012

A note on contralateral reexpansion pulmonary edema

Reexpansion pulmonary edema (RPE) is a rare but life thretening complication of evacuation of pleural fluid or air (pneumothorax). One interesting but poorly inderstood complication is development of RPE on the side contralateral to the lung that was drained.

RPE usually occur if a lung is collapsed for more than 3 days. It is recommended not to remove more than 1 liter of fluid in such instance. In other scenario, the procedure should be halted if the patient has sudden chest symptoms. Supplemental oxygen may be helpful too along with NIPPV and diuresis.

Thursday, March 1, 2012

Q; Size of ET Tube (Endotracheal Tube) represents what? (choose one)

A) Internal diameter of ETT
B) External diameter of ETT

Answer: Internal diameter of ETT

The “size” of an ET tube refers to its internal diameter. Therefore a “size 7 ” ET tube, means one with an internal diameter of 7 mm. ET tubes are usually labeled as ID (internal diameter) and OD (outside diameter).