29 Sep 07
Posted in Anesthesia, Pre-operatie evaluation at 21:47 by Laci
By Lee A. Fleisher, Joshua A. Beckman, Kenneth A. Brown, Hugh Calkins, Elliott Chaikof, Kirsten E. Fleischmann et al.
Circulation 2007;116:e418-e499
Conclusions
Successful perioperative evaluation and management of highrisk cardiac patients undergoing noncardiac surgery requires careful teamwork and communication between surgeon, anesthesiologist, the patient’s primary caregiver, and the consultant. In general, indications for further cardiac testing and treatments are the same as in the nonoperative setting, but their timing is dependent on several factors, including the urgency of noncardiac surgery, patient-specific risk factors, and surgery-specific considerations. The use of both noninvasive and invasive preoperative testing should be limited to those circumstances in which the results of such tests will clearly affect patient management. Finally, for many patients, noncardiac surgery represents their first opportunity to receive an appropriate assessment of both short- and long-term cardiac risk. Thus, the consultant best serves the patient by making recommendations aimed at lowering the immediate perioperative cardiac risk, as well as assessing the need for subsequent postoperative risk stratification and interventions directed at modifying coronary risk factors. Future research should be directed at determining the value of routine prophylactic medical therapy versus more extensive diagnostic testing and interventions.
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Posted in Inotropic support, Sepsis at 21:28 by Laci
By A Morelli, C Ertmer, M Westphal
Crit Care Med 2007;35:2447-2448
Arginine vasopressin belongs to the oldest substances in the pharmacologic armament of critical care physicians. The effects of purified pituitary extract on blood pressure were first recognized in the early 20th century. Although vasopressin and its analogs have emerged as standard drugs in the treatment of central diabetes insipidus and gastroesophageal hemorrhage, there is still no consensus on the use of vasopressin analogs in counteracting arterial hypotension. In cases of severe upper gastrointestinal bleeding, physicians often do not hesitate to administer several milligrams of terlipressin to terminate hemorrhage. Conversely, we are still very cautious with low-dose vasopressin infusion in septic shock patients, especially when such a concept yields to supraphysiologic plasma levels. And we are right to do so because several studies revealed severe complications after vasopressin administration in shock states. In this context, it is of note that most of these unwanted side effects are dose dependent. For example, van Haren et al. reported a proportional increase in the gastric mucosal Pco2 gap of septic shock patients in response to increased vasopressin plasma levels. On the contrary, several other clinical studies did not notice a negative effect of vasopressin therapy on organ function or outcome. Landry et al. even suggested relative vasopressin deficiency as a key factor in the pathogenesis of vasodilatory shock. In addition, the same authors noticed a pressor hypersensitivity in response to infusion of low vasopressin doses without obvious side effects.
Just recently, the results of the Vasopressin and Septic Shock Trial (unpublished) were presented at several major critical care meetings. These data provide evidence for the safety of a low-dose arginine vasopressin infusion (≤0.03 units/min), though the investigators did not observe an overall reduction in mortality. However, the results of an a priori analysis showed an improved survival rate of patients allocated to the vasopressin group in the less severe state of the disease (i.e., baseline norepinephrine dosage of <15 μg/min).
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26 Sep 07
Posted in Pacemaker - ICD at 18:31 by Laci
By B J Maron, P Spirito, W-K Shen, T S Haas, F Formisano, M S Link, A E Epstein, A K Almquist et al
JAMA. 2007;298:405-412
Recently, the implantable cardioverter-defibrillator (ICD) has been promoted for prevention of sudden death in hypertrophic cardiomyopathy (HCM). However, the effectiveness and appropriate selection of patients for this therapy is incompletely resolved.
Objective
To study the relationship between clinical risk profile and incidence and efficacy of ICD intervention in HCM.
Design, Setting, and Patients
Multicenter registry study of ICDs implanted between 1986 and 2003 in 506 unrelated patients with HCM. Patients were judged to be at high risk for sudden death; had received ICDs; underwent evaluation at 42 referral and nonreferral institutions in the United States, Europe, and Australia; and had a mean follow-up of 3.7 (SD, 2.8) years. Measured risk factors for sudden death included family history of sudden death, massive left ventricular hypertrophy, nonsustained ventricular tachycardia on Holter monitoring, and unexplained prior syncope.
Main Outcome Measure
Appropriate ICD intervention terminating ventricular tachycardia or fibrillation.
Results
The 506 patients were predominately young (mean age, 42 [SD, 17] years) at implantation, and most (439 [87%]) had no or only mildly limiting symptoms. ICD interventions appropriately terminated ventricular tachycardia/fibrillation in 103 patients (20%). Intervention rates were 10.6% per year for secondary prevention after cardiac arrest (5-year cumulative probability, 39% [SD, 5%]), and 3.6% per year for primary prevention (5-year probability, 17% [SD, 2%]). Time to first appropriate discharge was up to 10 years, with a 27% (SD, 7%) probability 5 years or more after implantation. For primary prevention, 18 of the 51 patients with appropriate ICD interventions (35%) had undergone implantation for only a single risk factor; likelihood of appropriate discharge was similar in patients with 1, 2, or 3 or more risk markers (3.83, 2.65, and 4.82 per 100 person-years, respectively; P = .77). The single sudden death due to an arrhythmia (in the absence of advanced heart failure) resulted from ICD malfunction. ICD complications included inappropriate shocks in 136 patients (27%).
Conclusions
In a high-risk HCM cohort, ICD interventions for life-threatening ventricular tachyarrhythmias were frequent and highly effective in restoring normal rhythm. An important proportion of ICD discharges occurred in primary prevention patients who had undergone implantation for a single risk factor. Therefore, a single marker of high risk for sudden death may be sufficient to justify consideration for prophylactic defibrillator implantation in selected patients with HCM.
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Posted in PA catheter at 18:25 by Laci
By R S Wiener, H G Welch
JAMA. 2007;298:423-429
Although there is now substantial evidence that pulmonary artery (PA) catheterization does not reduce mortality in critically ill patients, it is unknown whether national utilization has decreased in response.
Objective
To determine trends in PA catheterization use in the United States.
Design, Setting, and Participants
A time trend analysis on national estimates of PA catheterization utilization from 1993-2004 using data from all US states contributing to the Nationwide Inpatient Sample. Hospital admissions for those participants aged 18 years or older were assessed, with primary analysis focused on admissions with a medical diagnosis related group and a secondary analysis focused on surgical admissions. PA catheterization was identified by 5 International Classification of Diseases, Ninth Revision procedure codes describing PA or wedge-pressure monitoring, measurement of mixed venous blood gases, or monitoring of cardiac output by oxygen consumption or other technique.
Main Outcome Measure
Annual PA catheterization use per 1000 medical admissions.
Results
Between 1993 and 2004, PA catheterization use decreased by 65% from 5.66 to 1.99 per 1000 medical admissions (risk ratio [RR], 0.35; 95% confidence interval [CI], 0.29-0.42). Among patients who died during hospitalization, a group whose disease severity may be consistent across time, the relative decline was similar, decreasing from 54.7 to 18.1 per 1000 deaths (RR, 0.33; 95% CI, 0.28-0.38). A significant change in trend occurred following a 1996 study that suggested increased mortality with PA catheterization. The decline in utilization was similar in surgical patients (RR, 0.37; 95% CI, 0.25-0.49). Among common diagnoses associated with PA catheterization, the decline was most prominent for myocardial infarction, which decreased by 81% (RR, 0.19; 95% CI, 0.15-0.23), and least prominent for septicemia, which decreased by 54% (RR, 0.46; 95% CI, 0.38-0.54). Sensitivity analyses suggested findings were not due to artifact of changing procedure coding practice.
Conclusion
Use of the PA catheter, previously a hallmark of critical care practice, has decreased in the United States during the last decade, possibly due to growing evidence that this invasive procedure does not reduce mortality.
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