Thursday, March 31, 2011

Q: Fomepizole and ethanol are both use as treatment in Ethylene Glycol toxicity. What other medicines should be considered as adjuvant therapy in Ethylene Glycol toxicity?

Answer: Pyridoxine and Thiamine Pyridoxine (Vitamin B6) and Thiamine are cofactors in ethylene glycol metabolism and may be administered parenterally. On side note, while preparing antidotes early treatment with sodium bicarbonate should be initiated essential to correct acidosis. It may require upto 500-1000 mmol of bicarbonate within the first hours, especially if antidotal therapy is delayed.

Wednesday, March 30, 2011

Q: What is the ratio of albumin and an-ion gap drop?

Answer: With 1 gm/dL drop in albumin, an-ion gap drop by 2.5-3 mmol/L. Albumin is a major unmeasured anion. Every one gram decrease in albumin will decrease anion gap by 2.5 to 3 mmoles. In ICU you have to be very vigilant - where low albumin levels are very common - as a high anion gap acidosis in a patient with hypoalbuminaemia may appear as a normal anion gap acidosis.

Tuesday, March 29, 2011

Monday, March 28, 2011

Q: Describe few physiologic reasons of "overdamped" and "underdamped" arterial waveforms?

Answer:


Overdamping results in falsely low systolic and falsely high diastolic pressure.



  • aortic stenosis,

  • vasodilatation,

  • cardiogenic shock,

  • sepsis,

  • severe hypovolemia

Underdamping results in falsely high systolic pressures and falsely low diastolic pressures



  • hypertension,

  • atherosclerosis,

  • vasoconstriction,

  • aortic regurgitation,

  • hyperdynamic states such as fever

Sunday, March 27, 2011

Q: Which commonly used pressor in ICU may cause significant thrombocytopenia? Answer: Vasopressin Vasopressin infusion in advanced vasodilatory shock with severe multiorgan dysfunction causes platelet aggregation and induce thrombocytopenia. Its clinical significance is still undetermined.

Saturday, March 26, 2011

Q: Librium (Chlordiazepoxide) is a commonly used drug in ICU. Describe its four essential properties?

Answer: Chlordiazepoxide is unique in a sense and a good choice in alcohol withdrwawl not only because its active metabolite has a very long half life but also because it is

  • amnestic,
  • anxiolytic,
  • hypnotic and
  • skeletal muscle relaxant

Friday, March 25, 2011

Q: As patient rolled in your ICU with hypotension and massive ascites and you suspect intra abdominal hypertension, what is the first thing you should do?



Answer: First, Remove everything from patient's abdomen including any tight clothing, blankets, chart, IV bags, oxygen tank, monitor etc. Second, avoid overly aggressive fluid resuscitation.

Thursday, March 24, 2011

Q: 53 year old patient is admitted to ICU for septic shock secondary to diabetic foot. Surgical service decides to perform above knee amputation. What one thing you need to be careful while interpreting data from Pulmonary artery catheter?



Answer: Cardiac Index


Patient's status post Body Surface Area (BSA) is now changed due to loss of leg (above knee amputation). Remember Cardiac Index is a calculated value (CO/BSA). Its very important to change patient's weight on monitor. It may sound simple but may be an often forgotten value.

Wednesday, March 23, 2011

Q: Why IV Digoxin should be given slowly (over 5 minutes)?

Answer: Rapid infusion of Digoxin may cause systemic and coronary arteriolar constriction, which may precipate ischemia. Digoxin Injection should be given over a period of 5-7 minutes.

Tuesday, March 22, 2011

Scenario: 48 year old male patient is brought from OR to ICU after Coronary bypass (CABG). There was no peri-operative complication and whole procedure went smooth. IABP (Inta Aortic Baloon Pump) was inserted during surgery. On arrival perfusionist informed you that augmentation is not good. Per anesthesia report augmentation was good during the case?


Answer: In the OR the patient may be positioned with legs flexed for vein harvest. But when the legs are returned to neutral the IABP may well be pulled distally. It does not hurt to recheck the position of the IABP with TEE prior to transport to the ICU - or reposition with CXR in ICU.

Monday, March 21, 2011

Q: 78 year old male resident of assisted living facility presented to ER with severe pain going from 'loin to groin'. You suspect urosepsis. Indeed UA (urine analysis) showed WBC, and nitrites. Urine PH is reported 8. What would be your concideration in selecting antibiotics?



Answer: Cover Proteus, Pseudomonas, or Klebsiella.

Urea-splitting organism such as Proteus, Pseudomonas, or Klebsiella are likely to cause urine pH greater than 8.0 - and should be covered with antibiotics while cultures are pending.

Sunday, March 20, 2011

Q: 37 year old male is going for kidney transplant. Patient has ESRD (End Stage Renal Disease) secondary to hyperoxaluria. What suggestion you will have for surgery team?



Answer: Removal of the native kidneys.

In ESRD secondary to hyperoxaluria it is recommended to remove native kidneys at the time of renal transplantation. Native kidneys have residual stones, which makes them highly susceptible to recurrent infections and sepsis.

Saturday, March 19, 2011

Q: What's the difference of Levofloxacin (Levaquin) dose in hemodialysis and CRRT?

Answer: In hemodialysis, Levaquin dose is 500 mg initial dose, followed by 250 mg every 48 hours. It should be administrated on dialysis day after dialysis.

In CRRT: As Levaquin get cleared during CRRT dose is 500 mg every 48 hours or 250 mg every 24 hours but note that clearance dependent on filter type, flow rates, and other variables.

Friday, March 18, 2011

Q: What's the target of Urine PH in Aspirin overdose?


Answer: In Aspirin overdose, target urine pH is between 7.5-8.

Salicylate cause "neuroglycopenia" (lower CNS glucose level) despite normal serum glucose. As patient gets more and more acidotic, salicylate enters CNS and by direct effect cause neuroglycopenia. In such case more aggressive management is required including hemodialysis.

Hemodialysis is recommended in salicylate overdose patients with a level at or above 100 mg/dL (cut it to half if history suggest chronic ingestion). But if there is any sign of neurological manifestation, dialysis is indicated despite normal level.

7 indications of Hemodialysis in Salicylate poisoning

  1. Mental status change
  2. Pulmonary edema
  3. Cerebral edema
  4. Associated or with renal failure
  5. Level at or above 100 mg/dL(half if chronic ingestion)
  6. If fluid overload prevents alkalinization.
  7. Patient continue to deteriorate clinically.

Thursday, March 17, 2011

Q: Which route is preferable for Kayexalate adminstration - oral or rectal?



Answer: Rectal

Cation exchange resins (Kayexalate) can be administered orally or as a rectal retention enema. But as the major site of action is the colon, rectal administration is preferred particularly in hyperkalemic emergencies. Rectal enema is recommended to be retained for an hour. On safety note repeated enemas should be use with caution to prevent colonic perforation. The onset of action occurs within 2 hours.

Wednesday, March 16, 2011

Q: Describe role of urine alkalinization in barbiturate overdose?



Answer: Alkalinization of the urine is useful for long-acting barbiturates like phenobarbital and butalbital but is not recommended for short-acting barbiturate toxicity.

Phenobarbital has a higher water solubility and slow hepatic metabolism which allow a larger proportion of drug to be renally excreted. Urinary elimination may be achieved with an initial sodium bicarbonate bolus followed by an infusion to maintain a urine pH of greater than 7.5 (watch arterial pH). The goal should be a urine output of 150-250 mL/h.

Tuesday, March 15, 2011

Cardio-pulmonary arrest in cocaine overdose

Q: Why vasopressin is preferable over epinephrine in cardio-pulmonary arrest due to cocaine overdose?



Answer: Epinephrine like cocaine has alpha-adrenergic effects. Because of this similarity in the cardiovascular effects, the administration of epinephrine to a patient who arrests in a hyperadrenergic state has been like "pouring gasoline over fire."

Moreover, cocaine prevents the reuptake of exogenously administered epinephrine. Therefore, if epinephrine is used, AHA Guidelines recommends that high-dose epinephrine should be avoided and that the interval for its administration be increased (q 5-10min).

Vsopressin offer considerable advantages over epinephrine in cardiac arrest secondary to cocaine toxicity. The hyperadrenergic state caused by cocaine increases myocardial oxygen demand and vasopressin increases coronary blood flow, and thereby myocardial oxygen availablity.

Also, cocaine toxicity causes acidosis and epinephrine loses much of its effectiveness in an acidotic enviroment, whereas vasopressin demonstrates good efficacy even with severe acidosis.

Monday, March 14, 2011

Q; 52 year old female went into supraventricular tachycardia. While you call for Adenosine at bedside, clinical pharmacist inform you that patient is on chronic Aggrenox for her stroke?


Answer: Aggrenox is the combination of Aspirin and extended release Dipyridamole. Dipyridamole potentiates the action of adenosine so the lower doses (usually half) should be given.

Give only half of recommended dose of Adenosine.

Sunday, March 13, 2011

Q: What is "wedged blood PO2" and what is the clinical implication?


Answer: "Wedged blood Po2" is the level of PO2 while Pulmonary artery catheter baloon is inflated (wedging).

Wedge blood Po2 should be atleast 20 mm Hg higher than arterial PO2 (ABG) to confirm that you are measuring Pulmonary artery occlusion pressure at right level/spot.




Reference:

Paul L. Marino - The little ICU book of facts and Formulas, 2009 - Page 119

Saturday, March 12, 2011

Q: 52 year old male developed intracranial hemorrhage after receiving thrombolytic therapy for CVA. What is the treatment?


Answer: Transfusion of cryoprecipitate.

Prepare for administration of 6 to 8 units of cryoprecipitate containing factor VIII. It is not a bad idea to also adminster 6 to 8 units of platelets.

Friday, March 11, 2011


Holiday Heart Syndome

Holiday Heart Syndome was originally defined as "arrhythmias of the heart, sometimes apparent after a vacation or weekend away from work, following excessive alcohol consumption; usually transient". Same has been reported with recreational use of marijuana. The most common rhythm disorder is atrial fibrillation, which usually converts to normal sinus rhythm within 24 hours. It occurs in patients without structural heart disease and its clinical course is usually benign. Even modest alcohol intake may trigger paroxysmal atrial fibrillation.

Most patients with no evidence of structural heart disease can be discharged without further treatment once arrhythmia has stabilized with advise against the excessive use of alcohol. Patients with sustained tachyarrhythmia require treatment if the ventricular rate is excessive. Patients with structural heart disease needs further workup.

Thursday, March 10, 2011

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.

Wednesday, March 9, 2011

Ultrasound for Arterial lines - no brainer

Ultrasound guided placement of CVCs (central venous catheters) is now pretty much a standard in ICUS - at least in USA but fewer clinicians are using it for arterial catheterization.

This month of 'chest' has published a meta-analysis of 4 trials with a total of 311 subjects were included in the review, with 152 subjects included in the palpation group and 159 in the ultrasound-guided group.

Results showed that compared with the palpation method, ultrasound guidance for arterial catheterization was associated with a 71% improvement in the likelihood of first-attempt success.



Ultrasound-Guided Catheterization of the Radial Artery, A Systematic Review and Meta-analysis of Randomized Controlled Trials, Ariel L. Shiloh, MD, Richard H. Savel, MD, Laura M. Paulin, MD, MHS and Lewis A. Eisen, MD, FCCP. From the Division of Critical Care Medicine, Montefiore Medical Center and the Albert Einstein College of Medicine, Bronx, NY

Tuesday, March 8, 2011

Q; Which commonly use drugs in ICU may cause resistance to Heparin Therapy (failure of monitoring tests to change or higher than expected doses) ?


Answer:
The most important cause of apparent resistance to heparin therapy is antithrombin III deficiency. Replacement of antithrombin III in a deficient patient may restore heparin efficacy.

Also, its important to know that following commonly use medicines may cause resistance to heparin therapy.

  • intravenous nitroglycerin
  • digitalis,
  • nicotine (smoking),
  • tetracycline
  • some antihistamines


Reference:

Bick RL., Disorders of Thrombosis & Hemostasis. Clinical and Laboratory Practice. 1992. ASCP Press. (Figure 1-29 page 20; Table 14-7, page 305).

Monday, March 7, 2011

Lasix - bolus or continuous infusion?

Very interesting study published recently in NEJM looking into diuretic strategies in patients with acute decompensated heart failure.

In a prospective, double-blind, randomized trial, 308 patients with acute decompensated heart failure were assigned to receive furosemide administered intravenously by means of either a bolus every 12 hours or continuous infusion and at either a low dose (equivalent to the patient's previous oral dose) or a high dose (2.5 times the previous oral dose). The protocol allowed specified dose adjustments after 48 hours.

In the comparison of bolus with continuous infusion, there was no significant difference in patients' global assessment of symptoms or in the mean change in the creatinine level.

In the comparison of the high-dose strategy with the low-dose strategy, there was a nonsignificant trend toward greater improvement in patients' global assessment of symptoms in the high-dose group. The high-dose strategy was associated with greater diuresis and more favorable outcomes in some secondary measures but also with transient worsening of renal function.

It was concluded that among patients with acute decompensated heart failure, there were no significant differences in patients' global assessment of symptoms or in the change in renal function when diuretic therapy was administered by bolus as compared with continuous infusion or at a high dose as compared with a low dose.


Diuretic Strategies in Patients with Acute Decompensated Heart Failure, N Engl J Med 2011; 364:797-805, March 3, 2011

Sunday, March 6, 2011

NE and Dobutamine or Epinephrine alone?

In a recent study published from France compared epinephrine and norepinephrine-dobutamine in dopamine-resistant cardiogenic shock. It was an open, randomized interventional human study.

Thirty patients with a cardiac index of less than 2.2 and a mean arterial pressure of less than 60 mm Hg who were resistant to combined dopamine-dobutamine treatment and signs of shock were included. Patients were randomized to receive an infusion of either norepinephrine-dobutamine or epinephrine titrated to obtain a mean arterial pressure of between 65 and 70 mm Hg with a stable or increased cardiac index.

It was found that

  • both regimens increased cardiac index and oxygen-derived parameters in a similar manner.
  • Patients in the norepinephrine-dobutamine group demonstrated heart rates lower than those in the epinephrine group.
  • Epinephrine infusion was associated with new arrhythmias in three patients.
  • When compared to baseline values, after 6 hrs, epinephrine infusion was associated with an increase in lactate level, whereas this level decreased in the norepinephrine-dobutamine group.
  • Tonometered PCO2 gap, a surrogate for splanchnic perfusion adequacy, increased in the epinephrine-treated group while decreasing in the norepinephrine group.
  • Diuresis increased in both groups but significantly more so in the norepinephrine-dobutamine group, whereas plasma creatinine decreased in both groups.

It was concluded that when considering global hemodynamic effects, epinephrine is as effective as norepinephrine-dobutamine. Nevertheless, epinephrine is associated with a transient lactic acidosis, higher heart rate and arrhythmia, and inadequate gastric mucosa perfusion. Thus, the combination norepinephrine-dobutamine appears to be a more reliable and safer strategy.

Saturday, March 5, 2011

Percutaneous Aortic Valve Replacement!!
(Corevalve)


Friday, March 4, 2011

Q: What is the quick way of suspecting Pancreatitis secondary to alcohol intake?


Answer: The lipase/amylase ratio. A lipase/amylase ratio of greater than 2 suggests alcoholic pancreatitis.

note: many sources question the reliability of this ratio.

Thursday, March 3, 2011

Q: What is Fox's sign?

Answer: Fox's sign is ecchymotic patches seen over the inguinal ligament or the anterolateral surface of one or both thighs just below the inguinal ligament. The discoloration results from bloody fluid tracking extraperitoneally along the fascia of the psoas and iliacus muscles, becoming subcutaneous in the upper thigh. It occurs in patients with retroperitoneal bleeding, usually due to acute haemorrhagic pancreatitis. The sign is named after Dermatologist, Dr. Fox.


Wednesday, March 2, 2011

Case: 72 year old male presented after midnight when ancillary services (ultrasound or CT scan) are not available. Initial diagnosis is pneumonia with pleural effusion. What may help you in deciding "to tap or not to tap" (thoracentesis) the patient?



Answer: If there is a confusion about 'size of' pleural effusion, obtain lateral decubitus film. Measure the width of the layering pleural fluid. If the width of the fluid is less than 10 mm, the effusion can be managed medically or thoracentesis may be deferred. And if the effusion is wider than 10 mm, thoracentesis is recommended.

Tuesday, March 1, 2011

Case: 32 year old lean thin man presented to ED with 4 days of "Right" sided chest pain associated with shortness of breath. CXR showed sponteneous pneumothorax (PTX) on "Right" side. Chest tube is inserted with immediate resolution of PTX. 2 hours later patient complaint of shortness of breath again. Physical exam shows crackles on "Left " side?


Answer: "Contralateral" Reexpansion Pulmonary Edema

Reexpansion pulmonary edema (REPE) is a rare but known complication of evacuation of pleural effusion or pneumothorax. Usually it occurs on same side or both side but it may occur only in contralateral lung. Mechanism for this phenomenon is not known.

Risk for REPE is high if lung is collapsed for more than 3 days. If its secondary to pleural effusion it is recommended to remove no more than 1 liter of fluid. The treatment is supportive with supplemental oxygen, positive pressure ventilation, and diuresis.