Sunday May 3, 2009
Drug -Drug interaction / cardiology

Q: Which two commonly use drugs in CHF (congestive heart failure) - may oppose each other's action?

Answer: Aspirin and Furosemide (Lasix)

Lasix has a direct vasodilator effect and this effect begins within a few minutes after an administration of IV Lasix. This added effect is very useful in treatment of acute pulmonary congestion. But this desirable action can be blocked by nonsteroidal anti-inflammatory drugs including aspirin.

Mechanism of action is not clear but salicylates may inhibit the renal effects of loop diuretics that are mediated by prostaglandins, including increases in sodium excretion, renal blood flow, and plasma renin activity.

Read interesting commentary on this issue: Aspirin Use in Chronic Heart Failure, What Should We Recommend to the Practitioner? (Barry M. Massie, MD - J Am Coll Cardiol, 2005; 46:963-966


References:

1. Jhund PS, Davie AP, McMurray JJ. Aspirin inhibits the acute venodilator response to furosemide in patients with chronic heart failure. J Am Coll Cardiol. 2001;37:1234-1238

2. Effect of combined administration of furosemide and aspirin on urinary urate excretion in man - Journal of Molecular Medicine, Volume 57, Number 23 / December, 1979, 1299-1301

Saturday May 2, 2009
Dermatology

Q: What is the medical term for "cool, clammy, and mottled skin" in cardiogenic shock due to vasoconstriction and subsequent hypoperfusion of the skin?

Answer: Cutis Marmorata

Friday May 1, 2009
Use of Nebulized Lidocaine for Nasogastric Tube Insertion - Pros and cons

A double-blind, placebo-controlled, randomized clinical trial of adult patients was conducted in the EDs of 2 university hospitals. 29 participants were administered nebulized lidocaine (4 mL 10%), and 21 participants received nebulized normal saline solution *. Patient discomfort was measured using a 100-mm visual analog scale. The difficulty of nasogastric tube insertion was evaluated using a 5-point Likert scale.

Results:

• There was a clinical and statistical significant difference in patient discomfort associated with the passage of the nasogastric tube between nebulized lidocaine and placebo groups (mean visual analog scale score 37.7 versus 59.3 mm, respectively).
• There was not a detectable difference in difficulty with the passage of the nasogastric tube between the 2 groups
• Epistaxis occurred more frequently in the lidocaine group

Conclusion: Nebulized lidocaine decreases the discomfort of nasogastric tube insertion and should be considered before passing a nasogastric tube. An increased frequency of epistaxis, however, may be associated with its use.

* Four milliliters of the trial solution was administered using a face mask and a compressed gas-powered jet nebulizer with an oxygen flow rate of 6 L/min. The patient was instructed to breathe through his or her nose and mouth while the solution was being nebulized. Immediately after the nebulization was completed, the nurse removed the mask and inserted the nasogastric tube with the usual lubrication gel (KY Jelly) in the normal manner.



Reference: Click to get abstract

Nebulized Lidocaine Decreases the Discomfort of Nasogastric Tube Insertion: A Randomized, Double-Blind Trial - [Ann Emerg Med. 2004;44:131-137.]