Sunday October 25, 2009


Q: What is the basis of treatment for Torsade de Pointes?

Answer: The basis of treatment for Torsade de Pointe is sppression of early afterdepolarizations.

Magnesium is the drug of choice for suppressing EADs and terminating the arrhythmia. This is achieved by decreasing the influx of calcium, thus lowering the amplitude of EADs. Magnesium is effective even in patients with normal magnesium levels.

Some authorities recommend supplemental potassium to increase the potassium concentration to high normal, which increases the efflux of potassium from myocardial cells, thus causing rapid repolarization.

Saturday October 24, 2009
Medical Trivia

Do you know that -

Coumadin was first approved for medical use in humans in 1954. And a famous early recipient of warfarin was US president Dwight Eisenhower, who was prescribed the drug after having a heart attack in 1955.

Reference: The discovery of dicumarol and its sequels - Circulation. 1959 Jan;19(1):97-107

Friday October 23, 2009
Dexmedetomidine (precedex) reduce total extubation time?

Giving a patient dexmedetomidine prior to removing respiratory ventilation support reduced the total extubation time, according to research presented at the American Society of Anesthesiologists (ASA) 2009 annual meeting held this week in New Orleans. Researchers also found using the sedative resulted in fewer ventilator days and more successful extubation.

“Currently, if a patient cannot be successfully extubated, no viable alternative exists aside from performing additional weaning attempts and, in some cases, a tracheotomy,” said lead author Julin F. Tang, MD, MS, FCCM, clinical professor, Department of Anesthesia and Perioperative Care at San Francisco General Hospital. “This is tremendously hard on the patient. Now, based on the results of this study, dexmedetomidine may be a viable option for patients who have failed previous attempts to remove the respiratory tubes because it appears to inhibit a stress response in the body that can make it difficult to extubate.”

The prospective, randomized, controlled, IRB-approved study, "Dexmedetomidine Facilitates Extubation in Agitated SICU Patients Failing Previous Weaning Attempts," was conducted among 20 critically ill, intensive care patients who had failed previous attempts to remove ventilation support.

Participants not in the control group received dexmedetomidine at 0.5 or 0.7 mcg/kg/hr. Background sedation and analgesia were gradually decreased in the treatment group, and aerosolized lidocaine was initiated prior to weaning. Shortly after dexmedetomidine infusion, pressure support ventilation (PSV) was initiated and patients were weaned and extubated. Researchers measured the medication treatment group’s condition by checking the subjects’ arterial blood gases at three different points throughout the trial.

Following extubation, the amount of time required to take the tube out was distinctly shorter in patients who received dexmedetomidine. Ventilator time was shorter in these patients, and the rate of successful extubation was higher in the treatment group than the control group.

“Although the study size was relatively small, these results suggest that dexmedetomidine infusion during the weaning process may help control those problems that cause weaning attempts to fail such as agitation, tachypnea, tachycardia, and hypertension,” said Tang. “If a patient has these reactions, the medical team must refrain from pulling out the ventilator tube and try again the next day, which adds to the patient’s hospital costs as well as stress level.”


References: Click to get article

1. Study on the Use of Dexmedetomidine to Facilitate Extubation in Surgical Intensive-Care-Unit Patients Who Failed Previous Weaning Attempts - clinicaltrials.gov

2. Use of dexmedetomidine to facilitate extubation in surgical ICU patients who failed previous weaning attempts following prolonged mechanical ventilation: A pilot study - Respir Care 2006;51 (5):492-496.

3. Feasibility of dexmedetomidine in facilitating extubation in the intensive care unit - Journal of Clinical Pharmacy and Therapeutics, Volume 33 Issue 1, Pages 25 - 30, Published Online: 17 Jan 2008

Thursday October 22, 2009

Q: What's the basic difference between Phenytoin and Fosphenytoin?

Answer:

Phenytoin (Dilantin) is not water soluble, and must be solubilized in propylene glycol carrier with pH 12 to prepare IV form; therefore, cannot be given more than 50 mg/min without risk of significant hypotension and cardiac arrhythmias. Also major risk of potential irritation at IV site and vascular compromise of infused limb.

Fosphenytoin (Cerebyx) is a phosphorylated phenytoin prodrug. Highly water-soluble and therefore easier to administer than phenytoin. Enzymatically converted to phenytoin after mean 8 min and therefore can be administered more rapidly than standard phenytoin.

Wednesday October 21, 2009
Statin prophylaxis and inflammatory mediators following cardiopulmonary bypass: a systematic review shows evidence is still missing!


Introduction: Induction of an inflammatory response is thought to have a significant role in the complications that follow cardiopulmonary bypass (CPB). The statin drugs are increasingly being recognized as having potent anti-inflammatory effects and hence have potential to influence an important mechanism of injury in CPB. Our objective was to systematically review if pre-operative prophylactic statin therapy, compared with placebo or standard of care, can decrease the inflammatory response in people undergoing heart surgery with CPB.

Results: Eight RCTs were included in the review, with the number of trials for each inflammatory outcome being even more limited.

• Pooled data demonstrated benefit with the use of statin to attenuate the post-CPB increase in interleukins 6 and 8 (IL-6, IL-8), peak high sensitivity C-reactive protein (hsCRP), and tumor necrosis factor-alpha (TNF-a) post-CPB.
• Very limited RCT evidence suggests that prophylactic statin therapy may also decrease adhesion molecules following CPB including neutrophil CD11b and soluble P (sP)-selectin.

Conclusions: Although the RCT evidence may suggest a reduction in post-CPB inflammation by statin therapy, the evidence is not definitive due to significant limitations. Several of the trials were not methodologically rigorous and statin intervention was highly variable in this small number of studies. This systematic review demonstrates that there is a significant gap that exists in the current literature in regards to the potential anti-inflammatory effect of statin therapy prior to CPB.



Reference: click to abstract

Statin prophylaxis and inflammatory mediators following cardiopulmonary bypass: a systematic review: Critical Care 2009, 13:R165 (19 October 2009)

Tuesday October 20, 2009
3 preparations of Propofol

Propofol has 3 products available in market. They each contain different preservatives.

• The Hospira brand has Benzyl Alcohol,
• the Teva product has Sodium Metasulfite, and
• the APP product contains Edetate Disodium

Clinical significance: Some patients have allergies to sulfites so using the Teva product could be of concern in these instances.

Monday October 19, 2009


Question: What is Empyema necessitans?

Answer: Empyema necessitans is a rare complication of pleural space infections and occurs when the infected fluid dissects spontaneously into the chest wall from the pleural space. This process may result from bronchopleural extension of a peripheral lung infection. These cases result from inadequate treatment of an empyema and usually occur after a necrotizing pneumonia or pulmonary abscess.

XX-year-old male intravenous drug user with "empyema necessitans".
CT image shows empyema and draining chest wall abscess