Tuesday, July 31, 2007

Tuesday July 31, 2007

Q; In which heart valvular condition, Intra Aortic Balloon Pump (IABP) counterpulsation is contra-indicated for anginal symproms?

A; Severe Aortic valvular insufficiency (Aortic Regrurgitation).

It worsen the the diastolic augmentation of IABP and so the magnitude of regurgitation.

Monday, July 30, 2007

Monday July 30, 2007
Intractable ventriculat tachycardia in ventricular aneurysm

If any one of the clinical symptoms are present in Left Ventricular Aneurysm, surgery is indicated.

1. Angina
2. CHF
3. Systemic thrombolism
4. Malignant Arrhythmias

Intractable ventriculat tachycardia in the postmyocardial infarction patient should alert the physician for the presence of ventricular aneurysm. Establishment of circus movement between the aneurysmal and viable myocardium play a role. Ischemic dead and fibrosed tissue may help in establishing reentry phenomenon by creating an area of relative refractoriness and decrimental conduction. It can also act as an independently firing ectopic pacemaker site.


1. Left ventricular reconstruction: The aim and the reality after twenty years, J. Thorac. Cardiovasc. Surg., July 1, 2004; 128(1): 17 - 20.

2. Recurrent Ventricular Tachycardia, Successfully Treated by Excision of Ventricular Aneurysm - CHEST, VOL. 62, NO. 4, OCTOBER, 1972

Sunday, July 29, 2007

Sunday July 29, 2007
Treating Digoxin toxicity

Case: 74 year old male has been found to have arrhythmia with runs of wide complex ventricular tachycardia. Patient so far remained hemodynamically stable. You request crash cart near bed, applied pads to chest and send STAT labs and start reviewing patient's chart. You noticed 4 days ago digoxin level was 1.9 and since then his serum creatinine is steadily rising from 1.6 to 2.8. You suspected "Dig. toxicity" and called lab to run STAT dig. level. Indeed Dig. level is back with 3.4 and accompanying labs showed K+ level of 6.9. You ordered "Digi-bind" (Digoxin Immune Fab). Pharmacy informed you, "it will take time before Digi-bind gets to ICU". Interim you started treating hyperkalemia with IV insulin, D-50, IV bicarb., IV calcium and albuterol neb. treatments.Where did you go wrong ?

Answer: Calcium has shown to make digoxin toxicity worse. It may be more wise to avoid calcium in management of hyperkalemia from digoxin toxicity. Some literature has shown the similar membrane stabalizing effect from magnesium and may be used instead of calcium .Caution should be taken not to go very aggressive in treating hyperkalemia, or atleast potassium should be followed very closely if DigiFab is planned. With administration of DigiFab (Digibind), potassium shifts back into the cell and life threatening hypokalemia may develop rapidly. Digoxin causes a shift of potassium from inside to outside of the cell and may cause severe hyperkalemia but overall there is a whole body deficit of potassium. With administration of Digi-bind, actual hypokalemia may manifest which could be equally life threatening.

References: click to get abstract/article

1. Calcium for hyperkalaemia in digoxin toxicity - Emerg Med J 2002; 19:183

2. Using calcium salts for hyperkalaemia - Nephrol Dial Transplant (2004) 19: 1333-1334

3. Slow-release potassium overdose: Is there a role for magnesium? Emergency Medicine 1999;11:263–71

Saturday, July 28, 2007

Saturday July 28, 2007
Arterial and venous latate level

Arterial lactate level is preferable to venous lactate level but it is not always feasible to have arterial lactate level.To estimate accurate arterial level, following formula can be used

Arterial lactate in mmol/L = 0.889 (venous lactate in mmol/L) + 0.076

Please note this formula is in mmol/L. (In USA we use mg/dl). The unit conversion from mg to mmol is 1 mg/dl = 0.11 mmol/L.


Lavery RF, Livingston DH, et al. The utility of venous lactate to triage injured patients in the trauma center. J Am Coll Surg. 2000; 190: 656-664.

Friday, July 27, 2007

Friday July 27, 2007
What does EVH means when its written with CABG (coronary artery bypass grafting) ?

EVH means endoscopic vessel harvesting, which is a more refined method of removing, or harvesting, a vein from body to use as a graft during bypass surgery. Via an "endoscope", surgeon view the veins inside the leg and makes only one to three small incisions. The surgeon then removes a vein through one of the incisions. Compared to traditional vessel harvesting, EVH uses smaller incisions and may lead to less pain, faster healing, and smaller scars. It may be of extreme benefit in diabetic population, prone to infections, peripheral vascular disease and neuropathy.

To note, EVH takes significantly longer time compared to the traditional harvesting technique. Also, it has been said that carbon dioxide (CO2) insufflation used during EVH to facilitate the procedure may cause CO2 embolism but so far no significant data has shown reports of massive CO2 embolism with significant hemodynamic alterations.

References: Click to see abstract/article

1. Endoscopic saphenous vein harvesting for CABG -- a randomized, prospective trial. Thorac Cardiovasc Surg. 2002 Jun;50(3):160-3

Reduction of Carbon Dioxide Embolism for Endoscopic Saphenous Vein Harvesting - Thorac Surg 2006;81:1697-1699

Thursday, July 26, 2007

Thursday July 26, 2007
Amiodarone Neurotoxicity !!

Amiodarone neurotoxicity has been reported in up to 40% and may easily get miss or misdiagnose when an elderly patient presents with multiple symptoms. Major manifestation are peripheral neuropathy causing proximal motor weakness, ataxia and fine resting tremor. It may also present as neuromyopathy. A case has been described with autonomic dysfunction presented as incapacitating orthostatic hypotension. Cases has been reported with Amiodarone-Induced Delirium . Most neurotoxicities are dose related and resolved with discontinuation of Amiodarone. Being an intensivist it may be important to keep this very common dose related toxicity in mind while evaluating patient with neurologic symptoms.

Related pearl : Amiodarone pulmonary toxicity.

References: Click to see abstract/article

1. Amiodarone-Induced Neuromyopathy: Three Cases and a Review of the Literature - Journal of Clinical Neuromuscular Disease. 3(3):97-105, March 2002.

Severe Ataxia Caused by Amiodarone - Volume 96, Issue 10, Pages 1463-1464 (15 November 2005) - Am J of Card

Amiodarone toxicity presenting as pulmonary mass and peripheral neuropathy: the continuing diagnostic challenge - Postgraduate Medical Journal 2006;82:73-75

Amiodarone: Guidelines for Use and Monitoring - aafp.org - Vol 68, No. 11, Dec., 2003 -pdf

Atypical pulmonary and neurologic complications of amiodarone in the same patient. Report of a case and review of the literature - Vol. 147 No. 10, October 1, 1987 - Archive of Int Med.

Amiodarone-Induced Delirium - Am J Psychiatry 156:1119, July 1999

Wednesday, July 25, 2007

Wednesday July 25, 2007
pRBC transfusion and hyperkalemia

Hyperkalemia from blood transfusion is an under-recognised entity in ICUs but over time there is more realization about it. One recent study underscores the same peril from transfusion

A total of 131 patients were studied during the initial 12 hours after admission for noncrush trauma. 2 independent risk factors for hyperkalemia were

  • an ER plasma potassium level of 4.0 mmol/L or higher, and
  • transfusion of cell- or plasma-based products

Related previous pearl:
Transfusion-associated hyperkalemia in renal failure patients

Reference: click to get abstract
Resuscitative Hyperkalemia in Noncrush Trauma: A Prospective, Observational Study - Clin J Am Soc Nephrol.2007; 2: 313-319

Tuesday, July 24, 2007

Tuesday July 24, 2007
Do we need nicotine replacement therapy in ICU ?

Putting nicotine patch in patients with smoking history is a common practice in ICUs. But do we really need it ?

It was a retrospective study of 90 patients (smokers with application of nicotine replacement treatment) compared with 90 control patients (smokers who did not receive nicotine replacement therapy). Patients were adjusted based on the severity of illness and then age.

Outcome was measured by

  • hospital mortality and
  • 28-day ICU day


  • The observed hospital mortality rate was 20% in the cases vs. 7% in the control group ! (p = .0085).
  • When adjusted for the severity of illness and invasive mechanical ventilation, nicotine replacement therapy was independently associated with increased mortality.

Discussion (taken from study): Activation of the sympathetic nervous system is the main mechanism by which nicotine leads to cardiovascular disease. The sympathomimetic effect of nicotine is independent of the level of nicotine exposure. The hemodynamic effects of nicotine include increased heart rate, blood pressure, and myocardial contractility. It also may cause constriction of coronary arteries. Although these hemodynamic effects have not been shown to be associated with poor outcome in healthy volunteers and those with stable coronary artery disease, they may be detrimental in critically ill patients. Its effect of increasing myocardial oxygen consumption during times of reduced oxygen delivery may lead to adverse outcome in critically ill patients.

Reference: click to get abstract

1. The association of nicotine replacement therapy with mortality in a medical intensive care unit. Critical Care Medicine. 35(6):1517-1521, June 2007.

Monday, July 23, 2007

Monday July 23, 2007

Scenario: 58 year old female with rheumatoid arthritis admitted to ICU with community acquired pneumonia. Home medications include Methotrexate. Which group of Antibiotics should be preferably avoided ?

Answer: Penicillin

Penicillin has been shown to compete with the renal tubular secretion of methotrexate and hence its clearance, when coprescribed. Concurrent use of methotrexate and penicillin may increase the toxicity of methotrexate, particularly neutropenia.

Similar effects are reported from co-prescription of Bactrim also.

Reference: click to get abstract

Methotrexate induced neutropenia associated with coprescription of penicillins: serious and under-reported? - Rheumatology 2006 45(3):361-362

Pharmacokinetic interaction between methotrexate and piperacillin/tazobactam resulting in prolonged toxic concentrations of methotrexate - Journal of Antimicrobial Chemotherapy 2006 58(1):228-230

3. Methotrexate-induced pancytopenia associated with co-prescription of penicillin and trimethoprim Clinical Rheumatology, Volume 26, Number 1, January 2007 , pp. 134-135(2)

Sunday, July 22, 2007

Sunday July 22, 2007
Sign-out Mortality !

Regular evening work (sign-out) round is an integral part of all tertiary/teaching ICUs in USA but unfortunately as we transit to private practice or community hospital enviroment, we tend to loose this wonderful tradition. Ever thought of poor sign-out to your colleague as a patient safety issue? A group pf physicians from Chicago have published their study in Quality and Safety in Health Care.26 interns caring for 82 patients were interviewed after receiving sign-out from another intern. 25 discrete incidents, all the result of communication failures during the preceding patient sign-out, and 21 worst events were described. Omitted content (such as medications, active problems, pending tests) or failure-prone communication processes (such as lack of face-to-face discussion) emerged as major categories of failed communication. Ever think of sign-out as a procedure?

Read interesting article related to this topic Glucose Roller Coaster with sample signout sheet at the AHRQ WebM&M website, from Bradley A. Sharpe, MD, University of California, San Francisco .

Reference: click to get abstract

Communication failures in patient sign-out and suggestions for improvement: a critical incident analysis - Quality and Safety in Health Care 2005;14:401-407

Saturday, July 21, 2007

Saturday July 21, 2007
ever heard of carbicarb !!

Unfortunately Carbicarb is not available in USA but available in canada. It is a combination of sodium bicarbonate and sodium carbonate. It has been in use for about 20 years with good track record.

It has advantage over 'soda-bicarb' (NaHCO3) of not undergoing significant breakdown into CO2 and H2O. Also it is more predictable in raising PH. The dose is

0.2 x base deficit = mEq Sodium

Friday, July 20, 2007

Friday July 20, 2007
Colonic Necrosis - unusual complication of Kayexalate-Sorbitol

We are using sodium polystyrene sulfonate (SPS or Kayexalate) since last 45 years with great confidence. It is a common practice to add sorbitol to dissolve Kayexalate mainly to avoid fecal impaction or possible bowel obstruction. (Kayexalate binds intraluminal calcium and may cause constipation, fecal impaction or bowel obstruction). One of the relatively unknown complication of Kayexalate-sorbitol combination is colonic necrosis, although has been reported in literature earlier. The exact reason for colonic necrosis is not clear but the diagnosis can be made by the pathologic examination of post-operative specimen or material from endoscopic biopsy and may require specialized expertise and special stains. Sorbitol part is taught to be responsible for complication.

Intensivists need to be wary of possible complication of acute abdomen after administration of kayexalate-sorbitol in 1% of cases, particularly in first 24-36 hours.

Thursday, July 19, 2007

Thursday July 19, 2007
Preparation of

NOREPINEPHRINE (LEVOPHED) drip should be prepared in dextrose containing solution (D-5). NOREPINEPHRINE (LEVOPHED) is less stable in normal saline and loose its potency from oxidation over hours. Dextrose containg solution is preferred as the dextrose protects against oxidation of the norepinephrine and keep it active and stable.

Wednesday, July 18, 2007

Wednesday July 18, 2007
Xigris needs dedicated line

Before you write order for Xigris (APC), beaware that its infusion requires dedicated IV line, either peripheral or dedicated port of central line. The other solutions that can be administered through the same line are 0.9 NS, .45 NS, LR solution, D-5 or D5 with NS solutions.

Reference: Rxlist.com

Tuesday, July 17, 2007

Tuesday July 17, 2007
APC at one glance

Activated Protein C (Xigris) entered Critical Care Medicine culture with a big bang but over time its efficiency and safety has been questioned but still it is a valuable tool in intensivists' arsenals. Below is a nice picture showing various actions for APC application.

TF = tissue factor
IL-1 = interleukin 1
IL-6 = interleukin 6
TNF-alpha = tumor necrosis factor alpha
PAR-1 = protease activated receptor 1
EPCR = endothelial protein C receptor
TM = thrombomodulin

Click to get bigger image

source: Frontiers in Bioscience 11, 2381-2399, September 1, 2006

Monday, July 16, 2007

Monday July 16, 2007
Zolpidem-Induced Delirium

Relatively Zolpidem (Ambien) is a safe medicine and recently has been the drug of choice in critical care units to induce sleep. But it is important to be aware of reported cases of Ambien related psychosis, delirium and mania. Atleast one case is reported with visual perception distortion after a single dose of zolpidem. One way to combat the problem is to decrease the prescribing dose particularly in elderly population and in hypoalbuminemia (5 mg instead of 10 mg). Also, female population has been reported to have more plasma level with same dose. Also note that Zolpidem metabolized through liver so it may be necessary to decrease the dose in liver insufficiency.

Related previous pearls: SEROTONIN SYNDROME

References: click to get abstract/article

Delirium associated with zolpidem - The Annals of Pharmacotherapy: Vol. 35, No. 12, pp. 1562-1564
Zolpidem-Induced Delirium With Mania in an Elderly Woman - Psychosomatics 45:88-89, February 2004
Zolpidem-induced agitation and disorganization. - Gen Hosp Psychiatry. 1996 Nov;18(6):452-3. (pubmed)
Zolpidem-induced psychosis. - Ann Clin Psychiatry.1996 Jun;8(2):89-91. (pubmed)
5. Clinical pharmacokinetics of zolpidem in various physiological and pathological conditions, in Imidazopyridines in Sleep Disorders. Edited by Sauvanet JP, Langer SZ, Morselli PL. New York, Raven Press, 1988, pp 155–163
Zolpidem-Induced Distortion in Visual Perception - The Annals of Pharmacotherapy: Vol. 37, No. 5, pp. 683-686

Sunday, July 15, 2007

Sunday July 15, 2007

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.

Saturday, July 14, 2007

Saturday July 14, 2007
Norepinephrine friend or foe? - probably friend !

As we discussed earlier on this forum (see below related pearls) that overall trend is to use norepinephrine instead of dopamine as first line vasopressor in ICUs.

One step further, in july 2007 issue of Crititical Care medicine 1, laboratory investigation published regarding comparative effects of early versus delayed use of norepinephrine in resuscitated endotoxic shock.

5 groups (each group with 7 rats) were anesthetized, mechanically ventilated, paralyzed, and instrumented to measure mean arterial pressure, heart rate, pulse pressure variation, aortic and mesenteric blood flow, muscle and liver tissue oxygen pressure, blood gas, and lactate. 5 groups were

  1. endotoxin alone (Endo),
  2. endotoxin plus norepinephrine (Endo/NE),
  3. endotoxin plus fluid therapy alone (ENDO/Fl),
  4. endotoxin plus fluid therapy plus late catecholamine (Endo/Fl/Late NE), and
  5. endotoxin plus fluid therapy plus simultaneous norepinephrine administration (Endo/Fl/Early NE)

  • Mean arterial pressure increased to baseline values only in the catecholamine-treated group (p < .05).
  • In ENDO/Fl, Endo/Fl/Late NE, and Endo/Fl/Early NE, aortic blood flow was maintained.
  • Mesenteric blood flow was maintained at baseline values only in the catecholamine-treated groups
  • Mesenteric/aortic blood flow ratio was higher in the early catecholamine group (p < .05)
  • Endo and ENDO/Fl were associated with a marked decrease in liver Po2, which was maintained in catecholamine-treated groups (p < .01)
  • Plasma lactate was lower in the Endo/Fl/Early NE group
    Volume resuscitation was higher in Endo and
  • Endo/Fl/Late NE groups with 28 ± 6 and 27 ± 4 mL, respectively, when compared with the Endo/Fl/Early NE group (19 ± 3 mL) (p < .05)

Conclusions: The use of norepinephrine was associated with improved mean arterial pressure, sustained aortic and mesenteric blood flow, and better tissue oxygenation when compared with fluid resuscitation alone, irrespective of time of administration. The early use of norepinephrine plus volume expansion was associated with a higher proportion of blood flow redistributed to the mesenteric area, lower lactate levels, and less infused volume. Thus, the early use of norepinephrine is safe and may decrease the need for volume resuscitation

Previous Related pearls

Norepinephrine or Dopamine ? ,

Renal Dose Norepinephrine !

Is Dopamine phasing out?

Reference: click to get abstract/article

Comparative effects of early versus delayed use of norepinephrine in resuscitated endotoxic shock - Laboratory Investigations, Critical Care Medicine. 35(7):1736-1740, July 2007.
Renal Dose Norepinephrine! - Chest. 2004;126:335-337
Renal Effects of Norepinephrine in Septic and Nonseptic Patients - Chest. 2004;126:534-539
Noradrenaline and the kidney: friends or foes? - Crit Care 2001, 5:294-298
Vasopressor and inotropic support in septic shock: An evidence-based review. - Critical Care Medicine. 32(11) Supplement:S455-S465, November 2004

Friday, July 13, 2007

Friday July 13, 2007
cryo reduced plasma

Q: What is "cryo reduced plasma"?

A; One unit of cryoprecipitate is derived from one unit of fresh frozen plasma (FFP). Left over FFP, after removal of cryoprecipitate is called supernatant plasma or CRYO-REDUCED PLASMA.

Clinical Significance: Cryo-reduced plasma is used as a treatment in plasmapheresis for TTP, not responding to regular plasma exchange with FFP. Some physicians even use it as first line for plasmapheresis/Therapeutic Plasma Exchange (TPE) for a patient with Thrombotic Thrombocytopenic Purpura (TTP).

Thursday, July 12, 2007

Thursday July 12, 2007
Xenical (alli) and other life saving drugs

Anti-obesity drug Xenical (
Alli or orlistat) went over the counter with a big bang. Counters get cleared at major stores and pharmacies within hours.

It may be of importance to know its possible effect with warfarin (coumadin), cyclosporin and amiodarone. Alli is a reversible inhibitor of lipases. It forms a covalent bond with gastric and pancreatic lipases. The inactivated enzymes are thus unavailable to hydrolyze dietary fat in the form of triglycerides into absorbable free fatty acids and monoglycerides. As a side effect deficiency of fat-soluble vitamins like Vitamin A, D, E and K may occur. Recommendation is to take a multi-vitamin two hours before Alli. Patients on coumadin (warfarin) may have potential of bleed due to increase INR (as absorption of Vitamin K is decrease). We cannot find any mention in literature describing any such real case so far but frequent INR check is recommended for safety. Also to remember, Xenical can decrease the amount of cyclosporine and 25-30% reduction in systemic exposure to Amiodarone.

References: Click to see abstract/article

1. Mechanism of Action - Orlistat - Rxlist.com
2.Important Patient Information Patient Information about XENICAL - rocheusa.com
3.XENICAL - roche-australia.com

Wednesday, July 11, 2007

Wednesday July 11, 2007
Iodide in Thyroid Storm

Q; How long should you wait to administer iodide after giving antithyroid medication in the management of thyroid storm ?

A; Atleast one hour.Oral or rectal iodide compounds block release of thyroid hormones after starting antithyroid drug therapy. But if given early in management (before antithyroid medication become effective) it can get utilize in the synthesis of new thyroid hormone.

Read nicely written review on
Thyroid Storm (and Myxedema coma) by Nikolaos Stathatos, MD, and Leonard Wartofsky, MD from Washington Hospital Center in Washington, D.C. - ref.: emedmag.com, 02/15/2003 issue.

Tuesday, July 10, 2007

Tuesday July 10, 2007
Gadolinium based contrast agent (GBCA) and renal insufficiency

During MRI and MRA scans, a Gadolinium based contrast agent (GBCA) is used for more refined films. New evidences suggest that Gadolinium based contrast agents are associated with Nephrogenic Systemic Fibrosis (NSF) or Nephrogenic Fibrosing Dermopathy (NFD). Interestingly, the effect may be delayed upto 18 months after exposure !!

NSF may result in fatal or debilitating systemic fibrosis affecting the skin, muscle, and internal organs. Patients with renal dysfunction are at very high risk for NSF. In dialysis dependent patients, it is recommended to consider prompt hemodialysis following GBCA administration and upto 3 frequent sessions of dialysis. (Does it work ?). NSF is well documented following exposure to a GBCA in patients with

  • acute or chronic severe renal insufficiency (GFR less than 30) *
  • patients with acute renal insufficiency of any severity due to the hepato-renal syndrome or
  • in the peri-operative liver transplantation period

*To date, there has not been a report of NSF in a patient with normal renal function or mild to moderate renal insufficiency following GBCA exposure

Among the factors that may increase the risk for NSF are repeated or higher than recommended doses of a GBCA. The dose of gadolinium-based contrast agent given to patients undergoing an MRA is often higher and have higher risk of developing the condition.

The signs and symptoms of NSF includes itching, reddened or darkened patches on skin; and/or skin swelling, hardening and/or tightening. Yellow raised spots on the whites of the eyes. Joint stiffness and/or muscle weakness. In addition, patients may develop widespread fibrosis of other organs. A skin biopsy is necessary to confirm the diagnosis.

There is no treatment for NSF.

FDA has recently advised detailed box warning which can be read

Monday, July 9, 2007

Monday July 09, 2007
Male vs Female blood product transfusion (Plasma and apheresis platelets) !

Interesting study published in July 2007 issue of Critical Care Medicine
1 comparing transfusion from male-only versus female donors.

In this retrospective case-control study, 112 patients who received high plasma volume components (more than 2 units of fresh frozen plasma or apheresis platelets) from male-only donors were identified and compared them with from female donors. - patients matched by severity of illness, postoperative state, and number of transfusions. Baseline characteristics, ALI risk factors, and development of ALI were similar between the two groups.

  • Arterial oxygenation (Pao2/Fio2) worsened after the female (p = .008) but not after male-only donor product transfusion (p = .325).
  • Male-only component recipients had more ventilator-free days (median 28 vs. 27, p = .006) and
  • a trend toward lower hospital mortality rates (14% vs. 24%, p = .054).
  • no significant difference in development of ALI after transfusion.

Study concluded that in critically ill recipients of high plasma volume components, gas exchange worsened significantly after transfusion of female but not male donor components.

Reference: Click to get article/abstract

Transfusion from male-only versus female donors in critically ill recipients of high plasma volume components - Critical Care Medicine. 35(7):1645-1648, July 2007.

Few Previous Related Pearls:

FFP and platelet transfusion may be associated more with ALI/ARDS than pRBC transfusion

Why we call it cryoprecipitate?

How much FFP?

Sunday, July 8, 2007

Sunday July 08, 2007
iPods may interfere with pacemakers

Orginally reported at Reuters Health by By Megan Rauscher

Apple iPod MP3 music players may interfere with the functioning of implanted pacemakers, according to research reported at the Heart Rhythm Society's 28th annual scientific sessions in Denver, Colorado few weeks ago.

...............In their study, Dr. Krit Jongnarangsin of the University of Michigan, Ann Arbor and colleagues looked at the effect of four different iPod models (third generation, photo, video and Nano iPods) on implantable pacemaker function in 100 patients. A technician monitored intracardiac electrograms and a surface ECG while each iPod was held near the chest for 5 to 10 seconds in the on and off position.

The iPods, when held two inches from the patients' chest and as far as 18 inches, "interfered with pacemaker function in about one third of patients," Dr. Jongnarangsin noted in a telephone interview with Reuters Health. Pacemaker oversensing -- defined as spurious atrial/ventricular sensed events on the marker channel associated with atrial/ventricular inhibition, mode switching or high atrial/ventricular rates on rate histograms - was seen in 19% of patients.

Telemetry interference -- defined as any other interference that did not affect pacing function and was not detected by pacemaker interrogation -- occurred in 32%, and pacemaker inhibition in 1%. Oversensing and telemetry interference occurred more often with third generation iPods and the photo iPod than with the video and Nano iPod.

The observed iPod interference did not cause any clinical symptoms. "However, in one patient the iPod transiently inhibited pacemaker function," Dr. Jongnarangsin pointed out.

There is a concern, he added, that iPod interference might lead to an incorrect diagnosis of abnormal heart rhythm. "If we don't take into account that the patient has an iPod close to the pacemaker, we may assume that the patient has an abnormal heart rate rhythm," Dr. Jongnarangsin said.

"We need more information and more studies on iPod interference in pacemaker function," he concluded.

Friday, July 6, 2007

Saturday July 07, 2007

Q: Name atleast 3 causes of false postive result of prolonged PTT ?


  • Underfilled collecting tube (causing more than required citrate anticoagulant in tube)
  • Delay in performing assay (breakdown of cells)
  • Polycythemia (causing relatively less plasma volume)
Friday July 06, 2007
Treating cocaine induced hypertension

Cocaine induced hypertension is due to alpha-mediated vasoconstriction. Beta-blockers are advised to be avoided in the setting of cocaine toxicity because they may result in unopposed alpha effects of cocaine and may further increase the blood pressure. There are also some reports of seizures with B-blocker is such situation.

Calcium channel blockers dilate splanchnic vessels and thereby increasing absorption of ingested cocaine from the gastrointestinal tract, which may become disastrous in body packers. Nifedipine is also reported to potentiate the incidence of seizures and death after cocaine administration and should be avoided in the treatment of cocaine-induced hypertension.

Benzodiazepines is the first line of treatment in cocaine-induced hypertension. And if benzodiazepines fail to control hypertension, vasodilators, as nitroprusside and nitroglycerin should be use. And if vasodilators doesn't works, alpha-blockers, such as phentolamine is the next choice.

Thursday, July 5, 2007

Thursday July 05, 2007
Increased risk of severe protamine reactions in NPH dependent diabetics and with fish allergy

Protamine is a commonly used reversal for systemic heparinization after cardiac procedures. Protamine is well known for its relatively rare but severe anaphylaxis.

Patients using NPH are more prone to such reactions and caution should be exercise in such patients. Because NPH as stands for Neutral Protamine Hagedorn contains protamine, it is suspected that NPH insulin-dependent diabetic patients would develop sensitivity to protamine

Similarly, people allergic to fish are also prone to protamine reaction as afterall protamine comes from sperm of salmon fish !

Beside standard preacution (giving diluted and slowly) and treatment of anaphylaxis, methylene blue has been proposed as the treatment of protamine reaction

References: click to get abstracts/articles

Increased risk of severe protamine reactions in NPH insulin-dependent diabetics undergoing cardiac catheterization, Circulation, Vol 70, 788-792

PHYSICAL AND CHEMICAL PROPERTIES OF PROTAMINE FROM THE SPERM OF SALMON (ONCORHYNCHUS TSCHAWYTSCHA) - Paper originally published in 1957, source - Journal of Biological Chemistry

Catastrophic Cardiovascular Adverse Reactions to Protamine Are Nitric Oxide/Cyclic Guanosine Monophosphate Dependent and Endothelium Mediated Should Methylene Blue Be the Treatment of Choice? - Chest. 2002;122:1061-1066.

Wednesday, July 4, 2007

"Health care in the United States"

Wednesday July 04, 2007
Happy Birthday America

Today we selected following read on "Health care in the United States"

"The debate about U.S. health care concerns questions of access, efficiency, and quality purchased by the high sums spent. The overall performance of the United States health care system was ranked 37th by the World Health Organization (WHO) in 2000, but the same report assessed Americans' overall health at 72nd among 191 member nations included in the study.However, most Americans rate their own health as "excellent" or "very good". The National Health Interview Survey, released annually by the Centers for Disease Control's National Center for Health Statisticsreported that approximately 66% of survey respondents said they were in "excellent" or "very good" health in 2006. This percentage has been declining since 1998"

"Most Americans, 59.5%, receive their health insurance coverage through an employer, and about 9% purchase it directly from the market.Government sources cover 27.3% of the population (80.2 million).In 2005, there were 46.6 million people in the U.S. (15.9% of the population) who were without health insurance for at least part of that year. Among the uninsured, nearly 37 million were employment-age adults (ages 18 to 64), and more than 26 million worked at least part time. Approximately a quarter of the uninsured live in households with an income over $50,000.It is has been estimated that nearly one fifth of the uninsured population is able to afford insurance, almost one quarter is eligible for public coverage, and that the remaining 56% need financial assistance (8.9% of all Americans)".

you can have the full read
here (source: wikipedia.org)

Tuesday, July 3, 2007

Subarachnoid Hemorrhage - CT scan representation

Tuesday July 03, 2007
Subarachnoid Hemorrhage - CT scan representation

Subarachnoid hemorrhage occurs when a blood vessel just outside the brain ruptures. The area of the skull surrounding the brain, call the subarachnoid space rapidly fills with blood. Sometimes this is described as the worst headache of one's life.

Nice Review article on Subarachnoid Hemorrhage from emedicine.com

Monday, July 2, 2007

Monday July 02, 2007

Scenario: 88 year old female admitted to hospital after Non-Q wave MI. Patient required intubation during cardiac catheterization due to oversedation but pre procedure ABG was normal. Patient continue to have refractory hypoxemia. Workup for PE is negative with essentially normal chest CT. No infiltrates noted either. CXR is essentially normal too. Cardiac index is 2.7. Hpoxemia gets worse as PEEP was increased to counter hypoxemia. There is no auto-PEEP detected. Lactic acid and other workup is normal. Cardiac enzymes are actually improving. Regular Transthoracic Echo is normal. In short, you have a patient with stable labs and hemodynamics but with only refractory hypoxemia getting worse with increasing ventilator pressure.

Answer: Patent foramen ovale causing right to left shunt and worsening due to high right sided pressure from high PEEP. Patent foramen ovale is present in about 15% of the population. It get worse with age, usually from a mean of 3.4 mm in the first decade to 5.8 mm in the 10th decade of life. Any increase pressure on right side of heart may make it worse. Diagnosis can be made by bubble study during echocardiogram.

Bubble (contrast) study: After obtaining visualization of the atrial septum on echocardiography (transthoracic or transesophageal), a bolus of agitated saline is injected intravenously. Microbubbles will appear first in the right atrium. If the bubbles appear in the left atrium within 3 cardiac cycles of their appearance in the right atrium, the test is subjected to be call positive.

Treatment is closure of PFO surgically or by device. Or decreasing right sided pressure by IV nitro, diuresis and decreasing ventilator pressure till permanent solution can be intervened.

Sunday, July 1, 2007

Sunday July 01, 2007

On Sundays, we try to go little offbeat and try to provide other resources available on internet. Today our recommended site is

As name implies, it has live webcast and videos from previous webcasts of various surgeries including cardiac surgeries like Mitral valve repair, cardiac catherization procedure with angioplasty and stent placement etc.

The next live webcast will be on July 12, 2007 of closure of PFO (Patent Foramen Ovale) without open heart, using a closure device.

On July 24, 2007, there will be a live webcast on totally thoracoscopic epicardial RF ablation for Atrial Fibrillation.One interesting previous webcast was "Beating Heart Totally Endoscopic Coronary Artery Bypass" using da Vinci robotic assistance. Click here