Thursday July 9, 2009

Q: Tachyphylaxis to IV nitroglycerin drip develop in how many hours?

Answer: Tachyphylaxis to IV nitroglycerin develop approx. in about 16-24 hours.



References: Click to get abstract

1. Comparison of the degree of hemodynamic tolerance during intravenous infusion of nitroglycerin versus nicorandil in patients with congestive heart failure - Clinical Investigations - American Heart Journal. 134(3):435-441, September 1997.

Wednesday July 8, 2009

Q: Which very commonly use resuscitation fluid in ICU may cause pesudo-hyperamylasemia?


Answer: Hetastarch

The infusion of hydroxyethyl-starch leads to hyperamylasemia due to the complex structural interrelation of the amylase molecules in the serum and the hydroxyethyl-starch molecules. The amylase clearance is reduced because glomerular filtration of the macromolecules thus formed is not possible. It takes about a week for a level to return to normal after hetastarch infusion.

Workup for presumed pancreatitis may be expensive and futile.



References: Click to get abstract

1. Gofferje H, Kozlik V. [Hyperamylasemia following infusion of hydroxyethyl starch with different molecular weight distributions - Infusionsther Klin Ernahr. 1977 Jun;4(3):141-4

2. Treib J, Baron JF, Grauer-MT, Strauss-RG. An international view of hydroxyethyl starches. Intensive Care Med 1999;25:258–68.

Tuesday July 7, 2009
Assessment of Left Ventricular Function by Intensivists Using Hand-Held Echocardiography

Background: Bedside transthoracic echocardiography (TTE) provides rapid and noninvasive hemodynamic assessment of critically ill patients but is limited by the immediate availability of experienced sonographers and cardiologists.

Methods: Forty-four patients in the medical ICU underwent near-simultaneous limited TTE performed by intensivists with minimal training in echocardiography, and a formal TTE that was performed by certified sonographers and was interpreted by experienced echocardiographers. Intensivists, blinded to the patient's diagnosis and the results of the formal TTE, were asked to determine whether left ventricular (LV) function was grossly normal or abnormal and to place LV function into one of the following three categories:

• normal
• mildly to moderately decreased; and
• severely decreased
  

Results:

• Using the formal TTE as the “gold standard,” intensivists correctly identified normal LV function in 22 of 24 cases (92%) and abnormal LV function in 16 of 20 cases (80%).
• Intensivists correctly placed LV function into one of three categories in 36 of 44 cases (82%); in 6 of the 8 cases that were misclassified, the error involved an overestimation of LV function.

Conclusions: Intensivists were able to estimate LV function with reasonable accuracy using a hand-held unit in the ICU, despite having undergone minimal training in image acquisition and interpretation.

icuroom editors' note: All intensivists should be encouraged to seek minimal training in bedside echocardiography.



Reference: Click to get abstract

Assessment of Left Ventricular Function by Intensivists Using Hand-Held Echocardiography - CHEST June 2009 vol. 135 no. 6 1416-1420

Monday July 6, 2009

Q: Rewarming after therapeutic hypothermia should begun 24 hours after the

A) time of initiation of cooling or
B) from the time the target temperature (32-34 C) is achieved.

(Choose one)



Answer: Countdown for rewarming after therapeutic hypothermia should begun 24 hours after the time of initiation of cooling. The patient should be actively cooled by using an induced hypothermia protocol for 24 hours to a goal temperature of 32-34ºC. The goal is to achieve the target temperature as quickly as possible. In most cases, this can be achieved within 3-4 hours of initiating cooling.

See very good review article on Therapeutic Hypothermia (emedicine.com)

Sunday July 5, 2009
O2 Delivery & O2 Consumption curve in acute bleeding

Saturday July 4, 2009
Emergency Echocardiography

Friday July 3, 2009 (pediatric pearl)
Uniqueness of Neonatal/ Infantile Myocardium compared to adult myocardium

Neonatal myocardium has a large supply of mitochondria, nuclei and endoplasmic reticulum to support cell growth and protein synthesis but these are non-contractile tissues which render the myocardium stiff and non-compliant. This may impair filling of the left ventricle and limit the ability to increase the cardiac output by increasing stroke volume (Frank Starling mechanism). Stroke volume is therefore relatively fixed and the only way of increasing cardiac output is by increasing heart rate. The cardiac index (defined as the cardiac output related to the body surface area to allow a comparison between different sizes of patients) is increased by 30-60 percent in neonates and infants to help meet the increased oxygen consumption.

The sympathetic nervous system is not well developed predisposing the neonatal heart to bradycardia. Anatomical closure of the foramen ovale occurs between 3 months and one year of age.

Thursday July 2, 2009


Q: One unit of platelet transfusion expect to increase platelet count by how much ?

Answer; Each unit of platelet transfusion is expected to increase platelet count by 7 - 10,000 / uL. Platelet transfusion is usually given as 6 or 10 units together.

Wednesday July 1, 2009
Picture Diagnosis

Case: A 35-year-old man underwent pericardiectomy for pericarditis. Post procedure CXR and CT scan film is below, which shows a huge mass abutting the mediastinum in the left upper lung zone. Note: Pre-procedure CXR was normal and had no such mass!!

Answer: Gossypiboma

Gossypiboma is a technical term for retained surgical sponge. Patient underwent left upper lobectomy, and pathologic examination revealed gossypiboma (retained surgical sponge).