Q: 54 year old male is in ICU after Traumatic Brain Injury. Follow up CT scan shows cerebral edema. Resident ordered Mannitol. After 4 doses of Mannitol patient oxygen requirement on ventilator increased and CXR shows pulmonary edema. Resident ask you: If we are using mannitol to relieve cerebral edema than why does it cause the pulmonary edema?

Answer:

In patients with underlying cardiac or/and renal insufficiency, circulatory volume overload may occur due to expansion of extracellular fluid after serial mannitol administration causing pulmonary edema. It is true that mannitol is an osmotic diuretic but overwhelming hydrostatic pressure due to poor urinary output and underlying compromised cardiac function offsets the increased oncotic pressure and may lead to extravasation of fluid.

Mechanical AVR - Lower the INR?

BACKGROUND: Moderate anticoagulation after mechanical heart valve replacement has been proposed to reduce the risk of bleeding related to lifelong anticoagulation. However, the efficacy of such reduced antithrombotic regimens is still unknown. The present prospective open-label, single-center, randomized controlled trial aimed to evaluate the safety and feasibility of reduced oral anticoagulation after isolated mechanical aortic valve replacement.

METHODS: Low-risk patients undergoing bileaflet mechanical aortic valve replacement were randomized to a low International normalized ratio (INR) target (1.5-2.5; LOW-INR group) or to the standard currently recommended INR (2.0-3.0; CONVENTIONAL-INR group) through daily coumarine oral therapy. No aspirin was added. Median follow-up was 5.6 years. The primary outcome was assessment of noninferiority of the low over the standard anticoagulation regimen on thromboembolic events. Secondary end point was the superiority of the reduced INR target strategy on bleeding events.

RESULTS: We analyzed 396 patients (197 in the LOW-INR group and 199 in the CONVENTIONAL-INR group). The mean of INR was 1.94 +/- 0.21 and 2.61 +/- 0.25 in the LOW-INR and CONVENTIONAL-INR groups, respectively (P less than .001).

One versus three thromboembolic events occurred in the LOW-INR and CONVENTIONAL-INR, respectively, meeting the noninferiority criterion (P = .62).

Total hemorrhagic events occurred in 6 patients in the LOW-INR group and in 16 patients in the CONVENTIONAL-INR group (P = .04).

CONCLUSIONS: LOWERING-IT trial established that the proposed LOW-INR target is safe and feasible in low-risk patients after bileaflet aortic mechanical valve replacement. It results in similar thrombotic events and in a significant reduction of bleeding occurrence when compared to the conventional anticoagulation regimen.


LOWERing the INtensity of oral anticoaGulant Therapy in patients with bileaflet mechanical aortic valve replacement: results from the "LOWERING-IT" Trial, Am Heart J. 2010 Jul;160(1):171-8.

Q: 28 year old male is admitted with headache and back pain after a fall. Neurologist was called in ER who ordered CT of head and spine. ER physician called you admit patient for observation with diagnosis of pneumorrhachis. What is pneumorrhachis?

Answer: Pneumorrhachis means the presence of intraspinal air. It usually reabsorbs spontaneously and patients usually are managed conservatively but entrapped air may cause syndromes of intracranial and intraspinal hypertension. Clinical significance lies in finding potentially associated hidden and life threatening injuries. See below posterior epidural pneumorrhachisvwith pneumomediastinum.

Picture Diagnosis?

Answer: Subsegmental (or platelike or discoid Atelactasis)

It occurs due to obstruction of a small bronchus and may be seen in hypoventilation, pulmonary embolism, or pneumonia. Its called platelike atelactasis as it resembles the side-view of a dinner plate (see below).

Q: Steroids and diuretics are indicated in treatment of Transfusion-related acute lung injury (TRALI)

A) True
B) False



Answer: False

So far there is no evidence that steroids are helpful in TRALI. Another mistake would be to administer diuretics. TRALI is associated with microvascular damage and not fluid overload, so diuretics are not really helpful and actually not recommended. Since the pulmonary edema in TRALI is not related to fluid overload or cardiac dysfunction, it is logical that maintenance of adequate circulating volume is more beneficial - so it may even require IV fluid. Ventilatory assistance and circulatory support are the mainstays of treatment of TRALI. Diuretic use may be detrimental and could lead to hypotension.

TRALI is essentially a clinical diagnosis but one laboratory finding may include sudden fall in serum albumin.

Tamponade & Echo guided Pericardiocentesis

Q: 58 year old male with mechanical valve mitral valve replacement has 'little rocky course' post operatively in ICU. Patient was managed with IV heparin. Patient is initiated on Warfarin. Last INR was 3.8. Heparin is discontinued but laboratory called this morning with positive OD of 2.4 for 'HIT' (Heparin Induced Thrombocytopenia). Your next action would be?

A) Continue present management with Warfarin

B) Continue Warfarin but increase the INR target

C) Discontinue Warfarin

D) Discontinue Warfarin and start Argatroban

E) Discontinue Warfarin, administer vitamin K and start Argatroban




Answer: E

Warfarin may cause microthrombosis in patients HIT. These patients typically have severe protein C depletion. If warfarin has already been started, vitamin K should be given. Warfarin should not started before the platelet count is above 150.

In above question A and B are wrong as warfarin should be discontinued. C and D are right but not enough. E is the complete answer.

On therapeutic hypothermia

Q: How much cerebral metabolism goes down with reduction of each 1*C?


Answer: About 7%

Rationale for the effects of hypothermia as a neuroprotectant based on the slowing of cellular metabolism. For every one degree Celsius drop in body temperature, cellular metabolism slows by about 7%. Probably hypothermia reduces the harmful effects of ischemia by decreasing the body’s need for oxygen. More recent data suggests that hypothermia affects pathways that extend beyond a decrease in cellular metabolism.

Mnemonics for Infective endocarditis Duke criteria

BE FEVEER

Major:

B = blood culture +ve more than 2 times 12 hours part

E = Endocardial involvement from Echo


Minor:

F = Fever

E = Echo findings (not fulfilling a major)

V = Vascular findings *1

E = Evidences microbiological

E = Evidences immunological *2

R = Risk factors/predisposing factors - drug abuse, valvular diseases

Clinical criteria for infective endocarditis requires:

• Two major criteria, or

• One major and three minor criteria, or

• Five minor criteria

*1 major arterial emboli, septic pulmonary infarcts, mycotic aneurysm, intracranial hemorrhage, conjunctival hemorrhages, and Janeway lesions

*2 glomerulonephritis, Osler's nodes, Roth spots, and rheumatoid factor

Q: Dexmedetomidine (Precedex) should be use in caution with?

A) Renal failure

B) Liver Failure

C) Adrenal crisis

D) Tachycardia

E) Coagulopathy



Answer: ( B) Liver failure

Dexmedetomidine's undergoes hepatic metabolism. Caution should be used in patients with severe hepatic failure as elimination half life may be more than doubled. Normally dexmedetomidine has an elimination half life of 2 hours.

It has no effect in renal failure or adrenal crisis. It does not effect coagulation. Dexmedetomidine causes bradycardia and should be use with caution in bradycardia.

Q: Linezolid (Zyvox) may decrease the seizure threshold. Yes or No?


Answer: Yes

According to Pfizer package insert (maker of Zyvox):

"Convulsions have been reported to occur in patients when treated with Zyvox. In most of these cases, a history of seizures or risk factors for seizures was reported".

Half dose thrombolysis in PE?

Background: Optimal dosing of the recombinant tissue-type plasminogen activator (rt-PA) is important in treating pulmonary thromboembolism (PTE). The aim of this study was to compare the efficacy and safety of a 50 mg/2 h rt-PA regimen with a 100 mg/2 h rt-PA regimen in patients with acute PTE.

Methods: A prospective, randomized, multicenter trial was conducted in which 118 patients with acute PTE and either hemodynamic instability or massive pulmonary artery obstruction were randomly assigned to receive a treatment regiment of either rt-PA at 50 mg/2 h (n = 65) or 100 mg/2 h (n = 53). The efficacy was determined by observing the improvements of right ventricular dysfunctions (RVDs) on echocardiograms, lung perfusion defects on ventilation perfusion lung scans, and pulmonary artery obstructions on CT angiograms. The adverse events, including death, bleeding, and PTE recurrence, were also evaluated.

Results:

• Progressive improvements in RVDs, lung perfusion defects, and pulmonary artery obstructions were found to be similarly significant in both treatment groups. This is true for patients with either hemodynamic instability or massive pulmonary artery obstruction.
  
• Three (6%) patients in the rt-PA 100 mg/2 h group and one (2%) in the rt-PA 50 mg/2 h group died as the result of either PTE or bleeding.
  
• Importantly, the 50 mg/2 h rt-PA regimen resulted in less bleeding tendency than the 100 mg/2 h regimen (3% vs 10%), especially in patients with a body weight less than 65 kg (14.8% vs 41.2%, P = .049).
  
• No fatal recurrent PTE was found in either group.

Conclusions: Compared with the 100 mg/2 h regimen, the 50 mg/2 h rt-PA regimen exhibits similar efficacy and perhaps better safety in patients with acute PTE. These findings support the notion that optimizing rt-PA dosing is worthwhile when treating patients with PTE.

Efficacy and Safety of Low Dose Recombinant Tissue-Type Plasminogen Activator for the Treatment of Acute Pulmonary Thromboembolism: A Randomized, Multicenter, Controlled Trial - Chest February 2010 137:254-262

Q: What is the advantage of "oily Chloramphanicol"?



Answer: Oily chloramphenicol is the oil based solution of chloramphenicol. It is a long-acting preparation of chloramphenicol.

Oily chloramphenicol is recommended by the World Health Organization (WHO) as the first line treatment of meningitis in low-income countries. It has the great advantage of requiring only a single injection.

Though not very much in use in USA due to its bone marrow toxicity it is essential for intensivists to be aware of advantage of this drug. It has excellent blood brain barrier penetration with activity against a wide variety of Gram-positive, Gram-negative bacteria and anaerobic organisms .

Q: How much Aorta should be optimally occupied while Intra Aortic Balloon Pump (IABP) is inflated?



Answer: Optimally 85% of aorta should be occluded

With Intra Aortic Balloon Pump (IABP) the more blood displaced during diastole, the better the augmentation but total occlusion of aorta should be avoided.

Q: 54 year old male is admitted to ICU with Acute renal failure and diagnosed with Adult Polycystic Kidney Disease (ADPKD). 3 hours after his first hemodialysis session patient complains of severe headache. What would be your major concern?



Answer: Intracranial berry aneurysm

Approximately 10% of patients with ADPKD die of a ruptured, intracranial berry aneurysm. Patients also may develop hepatic cysts, pancreatic cysts, splenic cysts and pulmonary cysts.

Q: According to a 2009 science advisory from the American Heart Association/American Stroke Association - Upto what hours the expansion of the time window can be spread for treatment of acute ischemic stroke with intravenous Tissue Plasminogen Activator?

Answer: 4.5 hours

According to new recommendation:

"rtPA should be administered to eligible patients who can be treated in the time period of 3 to 4.5 hours after stroke (Class I Recommendation, Level of Evidence B). The eligibility criteria for treatment in this time period are similar to those for persons treated at earlier time periods, with any one of the following additional exclusion criteria: Patients older than 80 years, those taking oral anticoagulants with an international normalized ratio less than/=1.7, those with a baseline National Institutes of Health Stroke Scale score more than 25, or those with both a history of stroke and diabetes. Therefore, for the 3-to-4.5–hour window, all patients receiving an oral anticoagulant are excluded regardless of their international normalized ratio. The relative utility of rtPA in this time window compared with other methods of thrombus dissolution or removal has not been established. The efficacy of intravenous treatment with rtPA within 3 to 4.5 hours after stroke in patients with these exclusion criteria is not well established (Class IIb Recommendation, Level of Evidence C) and requires further study".

Expansion of the Time Window for Treatment of Acute Ischemic Stroke With Intravenous Tissue Plasminogen Activator - A Science Advisory From the American Heart Association/American Stroke Association - Stroke. 2009;40:2945.

Q: What is the recommended time period between 2 contrast related studies to avoid contrast induced nephropathy?


Answer: Ideally about 5 days

If multiple studies are needed, ideally 5 days should be kept between the studies to allow the kidneys to recover fully from the contrast.

Other steps should be taken like

• all nephrotoxic drugs should be discontinued,
• the minimal amount of contrast material should be used,
• nonionic agents should be preferred,
• patients should be well hydrated 12 hours before and 2 hours after a contrast-enhanced study.

Q: 28 years old male has repeated history of ED presentation with acute abdomen requiring narcotics analgesics. Record shows complete negative workup on each visit to ED. While evaluating this time your medical student suggested acute intermittent porphyria. Which test you should order?


Answer: Urine Porphobilinogen

Urine Porphobilinogen is a porphyrin precursor. This may not be included in hospital's standard urine porphyrin screen test and must be ordered specially. Acute intermittent porphyria patients have elevated porphobilinogen even between attacks though in some patients with long gaps between attacks, porphobilinogen may return to the normal range.

Q: How much blood is needed to turn guaiac-based fecal occult blood test positive?


Answer: About 10 ml over 24 hours

Normally, there is only about 1-2 ml of blood a day that escapes blood vessels into the stool per day.The common, traditional guaiac-based fecal occult blood test usually picks up a daily blood loss of about 10 ml

SVO2 vs ScVO2 - Keyword is 'trend'

Objective: To examine the validity of central venous oxygen saturation (ScvO ₂ ) as a numerical substitution of mixed venous oxygen saturation (SvO ₂ ) in adult patients undergoing normothermic on pump beating coronary artery bypass grafting (CABG).

Materials and Methods: Prospective clinical observational study was done at King Khalid University Hospital, King Saud University, Riyadh, Kingdom of Saudi Arabia. Thirty four adult patients scheduled for coronary artery surgery were included. Patients were monitored by a pulmonary artery catheter (PAC) as a part of our routine intraoperative monitoring. SvO ₂ and ScvO ₂ were simultaneously measured 15 minutes (T1) and 30 minutes (T2) after induction of anesthesia, 15 and 30 minutes after initiation of cardiopulmonary bypass (T3 and T4), and 15 and 30 minutes after admission to intensive care unit (T5 and T6).


Results:

• ScvO ₂ showed higher reading than SvO ₂ all through our study.
  
• Our results showed perfect positive statistically significant correlation between SvO ₂ and ScvO ₂ at all data points.

Individual mean of difference (MOD) between both the readings at study time showed MOD of 1.34 and 1.44 at T1 and T2 simultaneously. This MOD was statistically insignificant, but after on pump beating normothermic bypass was initiated; MOD was 5.2 and 4.4 at T3 and T4 with high statistical significance. In ICU, MOD continues to have high statistical significance, MOD was 6.3 at T5 and at T6 it was 4.6.

Conclusions: In on pump beating CABG patients; ScvO ₂ and SvO ₂ are not interchangeable numerically. ScvO ₂ is useful in the meaning of trend; our data suggest that ScvO ₂ is equivalent to SvO ₂ , only in the course of clinical decisions as long as absolute values are not required.

Mixed venous versus central venous oxygen saturation in patients undergoing on pump beating coronary artery bypass grafting - Saudi Journal of Anesthesia - Year : 2010 Volume : 4 Issue : 2 Page : 63-67

Q: 34 year old JW (Jehovah's Witnesses) patient is anemic post operatively. Surgeon wants to start erythropoetin or equivalent but patient refuse to have any albumin?


Answer:

You may start Aranesp(darbepoetin alfa)'s formulation without albumin. As of January 2007, the albumin-free version of Aranesp (R) is available in the United States. This is Polysorbate80 based version.

Q: What is the danger of synchronized cardioversion in the presence of hyperkalemia?


Answer:

Cardioversion in "synchronized" form reads the EKG so the shock occurs on an R wave. When you synchronize cardiovert someone, it may take few seconds until the defibrillator senses an R wave and delivers the shock. Sometimes it takes 3 or 4 QRS complexes to do this.

If the patient has severe hyperkalemia, sometimes the defibrillator may sense tall, peaked T waves as QRS complexes. If you deliver a cardioversion shock that is sync'd on the T wave, you may induce ventricular fibrillation.

Q: What is the easy way to calculate loading dose of Esmolol? (and drip rate)


Answer:

Divide patient's body weight in kg by 2
(eg, 70 kg/2 = 35 mg)

Multiply loading dose by 0.1 to get the mg/kg/min drip rate
(0.1 X 35 = 3.5 mg)

Q: In Hypothermia induced Ventricular fibrillation which cardiac medicine is preferred and which one may harm the patient?


Answer: Bretylium (5 mg/kg initially) is recommended for any hypothermic patient manifesting significant new frank dysrhythmia. However, bretylium has a worldwide shortage and may not be available. Relying on Amiodarone or Lidocaine are the next choices.

Procainamide may induce more ventricular fibrillation and should be avoided.

Defibrillation should also be performed simultaneously. Defibrillate at 2 J/kg (or the biphasic equivalent) if patient remains in ventricular fibrillation or ventricular tachycardia. Success rates of defibrillation are low if the core temperature is less than 32°C and should be performed with rise in body temperature. Actually, because many arrhythmias convert spontaneously upon rewarming, aggressive therapy of minor arrhythmias is not warranted. Transient ventricular arrhythmias should be ignored. This also is true of bradycardia or atrial arrhythmias.

The cornerstone of treatment is rewarming the patient

Intraarterial nicardipine and milrinone vasospasm in subarachnoid hemorrhage

BACKGROUND: Vasospasm is a potentially devastating complication after aneurysmal subarachnoid hemorrhage. Although endovascular treatment with intraarterial nicardipine and milrinone is an accepted clinical treatment strategy, there is little information either on hemodynamic management during treatment or on outcome and consequences of the hemodynamic management. We tested 2 hypotheses: (1) intraarterial administration of nicardipine and milrinone to treat cerebral vasospasm would require increased administration of vasoconstrictor to support arterial blood pressure at target levels; and (2) high-dose vasopressors administered to increase blood pressure in these patients would lead to systemic acidosis and end-organ ischemic damage.

METHODS: We conducted a single-center, retrospective review of consecutive patients with clinically symptomatic vasospasm after aneurysmal subarachnoid hemorrhage that failed medical management with “triple H therapy” and subsequently received intraarterial nicardipine and/or milrinone between March 2005 and July 2007.

RESULTS: Of 160 endovascular interventions in 73 patients (aged 52 ± 10 years; 50 women), 96 received only nicardipine, 5 only milrinone, and 59 both drugs. General anesthesia with muscle relaxation was performed for 93% of procedures.

• During treatment, both the number and dose of vasopressors required to maintain arterial blood pressure at target levels increased; the median dose of phenylephrine increased from 200 (n = 121) to 325 μg/min (n = 122), norepinephrine increased from 12 (n = 60) to 24.5 μg/min (n = 87), and vasopressin infusions increased from 7 to 24. Nonetheless, arterial blood pressure decreased 13% during treatment.
  
• In more than 90% of procedures, the postprocedure angiogram showed improved vessel caliber.
  
• A single patient demonstrated troponin T increase;
  
• no patients had a decrease in renal function, bowel or peripheral ischemia, systemic acidosis, or acute stroke.
  
• Overall mortality was 11%.

CONCLUSIONS: Intraarterial administration of nicardipine and/or milrinone requires use of vasopressors to maintain arterial blood pressure. Despite high doses of vasoconstrictors, treatment has low mortality, minimal end-organ ischemic damage or systemic acidosis, and results in improved caliber of cerebral vessels affected by vasospasm.

Hemodynamic Management and Outcome of Patients Treated for Cerebral Vasospasm with Intraarterial Nicardipine and/or Milrinone - Anesthesia & Analgesia, March 2010 vol. 110 no. 3 895-902

Q: Esmolol is metabolised in...?


A; RBC

Esmolol is called esmolol because it has side chain called Ester-methyl which allows for quick hydrolysis. Esmolol is rapidly hydrolyzed by esterases in the cytosol of red blood cells. Its metabolism is not affected by hepatic or renal failures

Pneumthoraces in HIV/PCP patients


Q: 38 year old male with AIDS presented to ICU with respiratory failure. Patient few hours after intubation developed pneumothorax. Chest tube is inserted but there was no resolution of pneumothorax. Senior resident inserted second chest tube without any relief. Hypoxia persisted?


A; The development of pneumothorax in the setting of severe PCP in AIDS patient, represents a difficult problem to manage, and patients may require multiple chest tubes or even surgical interventions. Mortality is very high.

Q: Which blood test can be use to monitor the progress or improvement of TTP (Thrombotic thrombocytopenic purpura) while on plasmapharesis?


A; LDH

Lactate dehydrogenase levels are generally used to monitor TTP activity. Plasmapheresis may need to be continued till patients cease to consume platelets. Research protocols have used improvement or normalization of LDH as a measure for ending plasmapheresis.

Q: Does Phenytoin (Dilantin) get cleared by hemodialysis or hemoperfusion?


A; No (clinically insignificant removal)

Clinical significance:

• In Phenytoin toxicity/overdose, Hemodialysis or hemoperfusion are ineffective for enhancing elimination.
• Hemodialysis patients do not require extra dosing post dialysis though require frequent monitoring due to lower albumin level.

IVIG for the treatment of Clostridium difficile?

Clostridium difficile is the most common infectious cause of nosocomial healthcare-associated diarrhea. The increasing prevalence of C difficile, spread in the community, virulence and frequent relapse has created an urgent need to identify new effective treatments for C. difficile infection. Among these, intravenous immunoglobulin (IVIG) is used for cases of severe C. difficile infection. We undertook a systematic review to examine the published literature pertaining to the use of immunoglobulin for C. difficile infection. Four retrospective studies and five case reports that addressed the use of IVIG for the treatment of C. difficile infection were identified. One study on the use of oral immunoglobulin was identified. Although overall there appear to be benefits to using IVIG in recurrent severe disease, the small sample sizes and lack of control groups in three of the four studies do not allow recommendations to be made regarding the use of immunoglobulin in C. difficile infection. Further research is urgently needed to clarify the role of immunoglobulin – intravenous or oral – for the treatment of C. difficile infection.

The role of immunoglobulin for the treatment of Clostridium difficile infection: a systematic review - INTERNATIONAL JOURNAL OF INFECTIOUS DISEASES, Volume 13, Issue 6, Pages 663-667 (November 2009)