Volatile agents for cardiac protection in noncardiac surgery: a randomized controlled study.

OBJECTIVE: Volatile anesthetics reduce the risk of myocardial infarction and mortality in coronary artery surgery. Recently, the American College of Cardiology/American Heart Association Guidelines suggested the use of volatile anesthetic agents for the maintenance of general anesthesia during noncardiac surgery in patients at risk for perioperative myocardial ischemia, but no randomized experience to document the cardioprotective effects of these agents exists in this setting. Therefore, the authors performed a prospective, randomized, controlled trial to compare the effects of sevoflurane versus total intravenous anesthesia, in terms of postoperative cardiac troponin I release in patients undergoing noncardiac surgery. DESIGN: A randomized, controlled trial. SETTING: A teaching hospital. PARTICIPANTS: Eighty-eight consecutive patients undergoing noncardiac surgery. INTERVENTIONS: Patients were allocated randomly to receive either volatile anesthetic (44 patients) as the main anesthetic agent or total intravenous anesthesia (TIVA) (44 patients). MEASUREMENTS: Postoperative cardiac troponin I release was measured as a marker of myocardial necrosis. Patients with detectable postoperative troponin I in the sevoflurane group (12/44, 27.3%) were similar to those in the propofol group (9/44, 20.5%; p = 0.6). There was no significant reduction of postoperative median peak cTnI release (0.16 ± 0.71 ng/mL in the sevoflurane group compared with the TIVA group, 0.03 ± 0.08 ng/mL; p = 0.4). Three patients died at the 1-year follow-up for noncardiac causes (2 in the TIVA group). CONCLUSIONS: In the authors' experience, patients undergoing noncardiac surgery did not benefit from anesthesia based on halogenated anesthetics. Further studies are necessary to evaluate the cardioprotective effects of volatile agents in noncardiac surgery.

Intrathecal lactate concentration and spinal cord injury in thoracoabdominal aortic surgery.

OBJECTIVE: The aim of this study was to evaluate the role of lactate as an early predictor of spinal cord injury during thoracoabdominal aortic aneurysm repair. DESIGN: Observational study. SETTING: University hospital. PARTICIPANTS: Sixteen consecutive patients (10 men and 6 women) scheduled to undergo thoracoabdominal aortic aneurysm repair were enrolled in the study. All patients were affected by atherosclerotic aneurysmal pathology. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: During surgery, the authors simultaneously withdrew samples of cerebrospinal fluid and arterial blood to evaluate pO(2), pCO(2), pH, and lactate concentration. Samples were collected at 5 fixed times during and after surgery: T1 (before aortic cross-clamping), T2 (15 minutes after clamping), T3 (just before unclamping), T4 (end of surgery), and T5 (4 hours after the end of surgery). Lactate levels in cerebrospinal fluid rose consistently during aortic cross-clamping (T1 = 1.89 mmol/L, T2 = 2.21 mmol/L, T3 = 2.88 mmol/L, T4 = 3.655 mmol/L, and T5 = 3.16 mmol/L). Lactate concentrations in the cerebrospinal fluid were significantly higher in the 4 patients who developed neurologic injury, even at T1 (before surgery), than in those who did not end in spinal cord injury with the 4 highest values belonging to the 4 patients who later developed spinal cord injury. CONCLUSIONS: This study has the potential to elucidate the time course of early lactate level elevation during thoracoabdominal aortic aneurysm repair and its clinical use in predicting the development of postoperative spinal cord injury.

Epidural analgesia improves outcome in cardiac surgery: a meta-analysis of randomized controlled trials.

OBJECTIVE: The authors conducted a review of randomized studies to determine whether there were any advantages for clinically relevant outcomes by adding epidural analgesia in patients undergoing cardiac surgery under general anesthesia. DESIGN: Meta-analysis. SETTING: Hospitals. PARTICIPANTS: A total of 2366 patients from 33 randomized trials. INTERVENTIONS: None. DATA SOURCES AND STUDY SELECTION: PubMed, BioMedCentral, CENTRAL, EMBASE, Cochrane Central Register of Controlled Trials, and conference proceedings were searched (updated January 2008) for randomized trials that compared general anesthesia with an anesthetic plan including general anesthesia and epidural analgesia in cardiac surgery. Two independent reviewers appraised study quality, with divergences resolved by consensus. Overall analysis showed that epidural analgesia reduced the risk of the composite endpoint mortality and myocardial infarction (30/1125 [2.7%] in the epidural group v 64/1241 [5.2%] in the control arm, odds ratio [OR] = 0.61 [0.40-0.95], p = 0.03 number needed to treat [NNT] = 40), the risk of acute renal failure (35/590 [5.9%] in the epidural group v 54/618 [8.7%] in the control arm, OR = 0.56 [0.34-0.93], p = 0.02, NNT = 36), and the time of mechanical ventilation (weighted mean differences = -2.48 hours [-2.64, -2.32], p < 0.001). CONCLUSIONS: This analysis suggested that epidural analgesia on top of general anesthesia reduced the incidence of perioperative acute renal failure, the time on mechanical ventilation, and the composite endpoint of mortality and myocardial infarction in patients undergoing cardiac surgery.

Spinal analgesia in cardiac surgery: a meta-analysis of randomized controlled trials.

OBJECTIVE: Controversial results exist on the effects of spinal analgesia in cardiac surgery. The authors conducted a review of randomized studies to show whether there are any advantages in clinically relevant outcomes using spinal analgesia in patients undergoing cardiac surgery. DESIGN: Meta-analysis. SETTING: Multiple hospitals. PARTICIPANTS: A total of 1,106 patients from 25 randomized trials. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULT: PubMed, BioMedCentral, CENTRAL, EMBASE, Cochrane Central Register of Controlled Trials, and conference proceedings were searched (updated January 2009) for randomized trials that compared general anesthesia with an anesthetic plan including spinal analgesia in cardiac surgery. Four independent reviewers performed data extraction, with divergences resolved by consensus. A total of 1,106 patients from 25 randomized studies were included in the analysis. Overall analysis showed that there were no differences in terms of mortality (2/562 [0.4%] in the spinal group v 2/514 [0.4%] in the control arm [risk difference (RD) = 0.00 [-0.02, +0.02], p = 1.0), perioperative myocardial infarction (9/421 [2.1%] in the spinal group v 11/407 [2.7%] in the control arm [RD = 0.00, -(0.03, +0.02), p = 0.77), and the length of hospital stay (WMD = -0.28 days [-0.68, -0.13], p = 0.18, with 419 included patients). CONCLUSIONS: This analysis indicated that spinal analgesia does not improve clinically relevant outcomes in patients undergoing cardiac surgery, discouraging further randomized controlled trials on this topic even if changes in techniques, devices, and drugs could modify the outlook of the comparison between spinal and standard anesthesia in this setting.

Prone versus knee-chest position for microdiscectomy: a prospective randomized study of intra-abdominal pressure and intraoperative bleeding.

STUDY DESIGN: Prospective randomized study. OBJECTIVES: To compare two support systems for positioning patients during microdiscectomy (i.e., prone on a modified Relton-Hall spine support vs. knee-chest position on an Andrews-type table) regarding their effects on intra-abdominal pressure and surgical bleeding. SUMMARY OF BACKGROUND DATA: Intra-abdominal pressure is an indicator of epidural venous pressure, which affects bleeding during microdiscectomy. The ideal patient's position during surgery reduces bleeding by minimizing abdominal compression and vertebral venous engorgement. The results of previous studies on the relationship between intra-abdominal pressure and blood loss during spinal surgery are not consistent, and hardly comparable because they used different measurement systems and support frames. METHODS: A total of 30 patients with the American Society of Anesthesiologists physical status I or II undergoing elective, single-space lumbar microdiscectomy had their intra-abdominal pressure measured through a urinary bladder catheter, together with airway pressure: (1) supine after anesthesia induction; (2) in prone position (group P) or knee-chest position (group K), according to randomization; or (3) at the end of surgery before repositioning the patient supine. RESULTS: Baseline intra-abdominal pressure did not differ between groups, and intra-abdominal pressure did not vary significantly from baseline in both groups throughout the study. Baseline airway pressure did not differ between groups. Airway pressure was significantly increased from baseline at the recording before incision in group K and at the end of surgery in both groups. Recordings before incision and at the end of surgery differed significantly from one another in both groups. Such airway pressure variations did not differ between groups. Bleeding was significantly more prominent in group K (P = 0.007). No correlation between bleeding and intra-abdominal pressure or airway pressure was found. CONCLUSIONS: Intra-abdominal pressure did not differ between prone position on a modified Relton-Hall frame and knee-chest position on an Andrew-type table. Both positions provide good conditions for lumbar microdiscectomy.

Characteristics of repeat users of an inpatient psychiatry service at a large military tertiary care hospital.

OBJECTIVE: The purpose of this study was to identify clinical and demographic variables that correlated with readmission to a large tertiary care military psychiatric inpatient service located in the Washington, DC area. METHODS: Data from 983 consecutive inpatient admissions (comprised of 814 individual patients) over a 13-month period (July 1999-July 2000) were abstracted from medical records for retrospective analysis. Repeat users were defined as those individuals receiving two or more inpatient admissions to Walter Reed Army Medical Center during the study period. Statistical comparisons were made between repeat and single admission groups to identify variables predictive of rehospitalization. RESULTS: Of 814 individual patients under study, 117 (14%) were identified as repeat users. A history of childhood psychiatric problems, previous psychiatric hospitalization, current or past substance abuse, legal problems, and presence of a psychotic or nonbipolar mood disorder were associated with readmission after controlling for active duty status. Current comorbid substance use or personality disorder diagnoses were not predictive. Having at least one child was protective against readmission. The 117 repeat users accounted for 3,838 (37%) of the total 10,393 hospital bed-days during the study period. Logistic regression analysis of all variables correlated with readmission demonstrated statistical significance for past psychiatric hospitalization and age of onset of psychiatric problems before age 18 when active duty status, age, and gender variables were included in the equation. CONCLUSIONS: This study is one of the largest to investigate predictors of rehospitalization in a population that enjoys universal "free" access to comprehensive mental health care services and other benefits of employment. This retrospective analysis documented three important facts: That there seem to be only minor differences between military and civilians with respect to variables associated with psychiatric rehospitalization, that a relatively small proportion of patients accounted for a disproportionately large number of inpatient bed-days, and that an unexpectedly high proportion of active duty patients admitted to this study site reported childhood psychiatric problems and psychiatric hospitalizations before their first hospitalization at Walter Reed Army Medical Center.