Akiko Taguchi

Thoracic epidural anesthesia increases tissue oxygenation during major abdominal surgery.

Intraoperative surgical stress may markedly increase adrenergic nerve activity and plasma catecholamine concentrations, which causes peripheral vasoconstriction and decreased tissue oxygen partial pressure possibly leading to tissue hypoxia. Tissue hypoxia is associated with an increased incidence of surgical wound infections. Thoracic epidural anesthesia blocks afferent neural stimuli and inhibits efferent sympathetic outflow in response to painful stimuli. Consequently, we tested the hypothesis that supplemental thoracic epidural anesthesia during major abdominal surgery improves tissue perfusion and subcutaneous oxygen tension. Thirty patients were randomly assigned to two groups: general (n = 15) or combined general and epidural anesthesia (n = 15). Anesthesia technique and fluid management were standardized. Subcutaneous tissue oxygen tension was measured continuously in the upper arm with a Clark type electrode. Data were compared with unpaired, two-tailed t-tests, Wilcoxon’s ranked sum test, or repeated-measures analysis of variance and Scheffé F tests as appropriate; P < 0.05 was considered statistically significant. After 60 min, intraoperative tissue oxygen tension was significantly larger during combined anesthesia than during general anesthesia (54.3 ± 7.4 mm Hg versus 42.1 ± 8.6 mm Hg; P = 0.0002). Subcutaneous tissue oxygen tension remained significantly higher in the combined general/epidural anesthesia group throughout the observation period. Hemodynamic responses and global oxygen variables were similar in the groups. Thoracic epidural anesthesia improved intraoperative tissue oxygen tension outside the area of the epidural block. Thus, our results give evidence that supplemental neural nociceptive block blunts generalized vasoconstriction caused by surgical stress and adrenergic responses.

Effects of a circulating-water garment and forced-air warming on body heat content and core temperature.

Background: Forced-air warming is sometimes unable to maintain perioperative normothermia. Therefore, the authors compared heat transfer, regional heat distribution, and core rewarming of forced-air warming with a novel circulating-water garment. Methods: Nine volunteers were each evaluated on two randomly ordered study days. They were anesthetized and cooled to a core temperature near 34°C. The volunteers were subsequently warmed for 2.5 h with either a circulating-water garment or a forced-air cover. Overall, heat balance was determined from the difference between cutaneous heat loss (thermal flux transducers) and metabolic heat production (oxygen consumption). Average arm and leg (peripheral) tissue temperatures were determined from 18 intramuscular needle thermocouples, 15 skin thermal flux transducers, and “deep” hand and foot thermometers. Results: Heat production (approximately 60 kcal/h) and loss (approximately 45 kcal/h) were similar with each treatment before warming. The increases in heat transfer across anterior portions of the skin surface were similar with each warming system (approximately 65 kcal/h). Forced-air warming had no effect on posterior heat transfer, whereas circulating-water transferred 21 ± 9 kcal/h through the posterior skin surface after a half hour of warming. Over 2.5 h, circulating water thus increased body heat content 56% more than forced air. Core temperatures thus increased faster than with circulating water than forced air, especially during the first hour, with the result that core temperature was 1.1° ± 0.7°C greater after 2.5 h (P < 0.001). Peripheral tissue heat content increased twice as much as core heat content with each device, but the core-to-peripheral tissue temperature gradient remained positive throughout the study. Conclusions: The circulating-water system transferred more heat than forced air, with the difference resulting largely from posterior heating. Circulating water rewarmed patients 0.4°C/h faster than forced air. A substantial peripheral-to-core tissue temperature gradient with each device indicated that peripheral tissues insulated the core, thus slowing heat transfer.

Supplemental Intravenous Crystalloid Administration Does Not Reduce the Risk of Surgical Wound Infection

Wound perfusion and oxygenation are important determinants of the development of postoperative wound infections. Supplemental fluid administration significantly increases tissue oxygenation in surrogate wounds in the subcutaneous tissue of the upper arm in perioperative surgical patients. We tested the hypothesis that supplemental fluid administration during and after elective colon resections decreases the incidence of postoperative wound infections. Patients undergoing open colon resection were randomly assigned to small-volume (n = 124, 8 mL · kg−1 · h−1) or large-volume (n = 129, 16–18 mL · kg−1 · h−1) fluid management. Our major outcomes were two distinct criteria for diagnosis of surgical wound infections: 1) purulent exudate combined with a culture positive for pathogenic bacteria, and 2) Center for Disease Control criteria for diagnosis of surgical wound infections. All wound infections diagnosed using either criterion by a blinded observer in the 15 days after surgery were considered in the analysis. Wound healing was evaluated with the ASEPSIS scoring system. Of the patients given small fluid administration, 14 had surgical wound infections; 11 given large fluid therapy had infections, P = 0.46. ASEPSIS wound-healing scores were similar in both groups: 7 ± 16 (small volume) versus 8 ± 14 (large volume), P = 0.70. Our results suggest that supplemental hydration in the range tested does not impact wound infection rate.

Temperature Monitoring and Management During Neuraxial Anesthesia: An Observational Study

Temperature monitoring and thermal management are rare during spinal or epidural anesthesia because clinicians apparently restrict monitoring to patients with an expected risk of hypothermia. This implies that anesthesiologists can predict patient thermal status without monitoring core temperature. We therefore, tested the hypotheses that during neuraxial anesthesia: 1) amount of core hypothermia depends on the magnitude and duration of surgery; 2) temperature monitoring and thermal management are used selectively in patients at high risk of hypothermia; and 3) anesthesiologists can estimate patient thermal status. We evaluated thermal status on arrival in the recovery room along with intraoperative thermal management and monitoring in 120 patients. Anesthesiologists were asked if their patients were hypothermic (<36°C). There was no correlation between the magnitude or duration of surgery and initial postoperative core temperature in unwarmed patients. Temperature monitoring and thermal management were not used selectively in high-risk patients. Initial postoperative tympanic membrane temperatures were <36°C in 77% of patients and <35°C in 22%. Body temperature was monitored intraoperatively in 27% of the patients and forced-air warming was used in 31%. Anesthesiologists failed to accurately estimate whether their patients were hypothermic. Our results suggest that temperature monitoring and management during neuraxial anesthesia is currently inadequate. Implications In this observational study, we evaluated core temperatures and intraoperative thermal management in patients undergoing spinal or epidural anesthesia. Hypothermia was common, however, rarely detected either by temperature monitoring or estimates by anesthesiologists. In addition, it was not treated with active warming. Consequently, temperature monitoring and management have to be done during neuraxial anesthesia.

Postoperative nausea and vomiting following inpatient surgeries in a teaching hospital: a retrospective database analysis

ABSTRACT Objective: To report the incidence of postoperative nausea and vomiting (PONV), to describe the use of anti-emetics both for the prophylaxis and treatment of PONV, and to assess resource utilization and duration of post-anesthesia care unit (PACU) stay. Research design and methods: We retrieved data from the Duke Anesthesia Peri-operative database. We included adult patients, who underwent inpatient surgery under general anesthesia with inhaled agents between January 2004 and February 2005, and had two or more risk factors for PONV documented preoperatively (female, previous history of PONV or motion sickness, non-smoker or use of postoperative opioid). Data on the use of prophylactic anti-emetics, the incidence of PONV, nausea scores, pain scores, and the use of rescue anti-emetics in PACU and in the period between PACU discharge and 24 h after surgery were recorded. Resource utilization and cost assessment was performed from the perspective of the hospital and included length and direct cost of PACU stay, as well as the acquisition costs of rescue anti-emetics in PACU. Descriptive statistics were used to summarize the demographic characteristics of patients. For group comparisons, data were analyzed with the t‐test for continuous data, and the Chi-square test for categorical data. Multiple linear regression models were used to evaluate the association between PONV and PACU length of stay adjusting for confounding factors. Results: A total of 3641 patients were included in the analysis. Of those, 2869 (79%) received prophylactic anti-emetics. In the PACU, nausea and vomiting were reported in 16% and 3% of the patients, respectively. Rescue anti-emetics were given to 26% of all patients. The incidence of vomiting was significantly less in patients who received PONV prophylaxis ( p = 0.03). In multiple linear regression models, the duration of PACU stay was longer by a mean of 25 min in patients who experienced PONV or received rescue anti-emetics in PACU ( p < 0.0001) despite the fact that the duration of surgery was shorter by a mean of 24 min in this group of patients ( p < 0.0001). Following PACU discharge, 40% of patients reported nausea, vomiting or needed rescue anti-emetics. PONV was associated with significantly increased resource utilization and costs of PACU stay ( p < 0.0001). Emesis was associated with greater incremental cost (

Effect of supplemental pre-operative fluid on postoperative nausea and vomiting

138) than nausea (

Preoperative oral rofecoxib does not decrease postoperative pain or morphine consumption in patients after radical prostatectomy: a prospective, randomized, double-blinded, placebo-controlled trial.

85), mainly from the longer duration of PACU stay. Conclusions: PONV remain a significant problem postoperatively and often persists beyond PACU discharge. The presence of PONV is associated with increased length of PACU stay and greater resource utilization and costs.

A Comparison of Ondansetron with Promethazine for Treating Postoperative Nausea and Vomiting in Patients Who Received Prophylaxis with Ondansetron: A Retrospective Database Analysis

In a prospective, double‐blind, randomised controlled trial, we studied the effects of pre‐operative fluid load on post‐operative nausea and vomiting. Eighty patients attending for laparoscopic cholecystectomy or gynaecological surgery were randomly allocated to receive 2 ml.kg−1 (conservative) or 15 ml.kg−1 (supplemental) Hartmanns solution intravenously, shortly before induction of anaesthesia. During the operation, fluid management was identical in both groups. During the first post‐operative 24 h, post‐operative nausea and vomiting occurred in 29 patients (73%) in the conservative fluid group and nine patients (23%) in the supplemental fluid group (p = 0.01). Supplemental pre‐operative fluid is an inexpensive and safe therapy for reducing post‐operative nausea and vomiting.

The effect of auricular acupuncture on anaesthesia with desflurane

STUDY OBJECTIVES To evaluate the analgesic efficacy of the rofecoxib po before radical prostatectomy. DESIGN Prospective, randomized, double-blinded, placebo-controlled trial. SETTING Teaching hospital. PATIENTS Anesthetic management was standardized. Patients received either a 50-mg rofecoxib capsule or a placebo capsule po 1 hour before induction of anesthesia. MEASUREMENTS AND MAIN RESULTS Patient-generated 10-cm visual analog scale (VAS) scores for pain were assessed at 1, 2, 4, 6, 8, and 24 hours after surgery. Morphine consumption was recorded from a patient-controlled analgesia device at the same time. A patient-generated overall pain relief score was obtained at 24 hours after surgery. We were unable to detect any differences between study groups with respect to postoperative morphine consumption, VAS score, or overall pain relief score. CONCLUSIONS When rofecoxib is used po in maximum recommended doses before surgery, it does not provide significant analgesia that results in reduction in pain scores or analgesic requirements for patients after radical prostatectomy.

Dantrolene Reduces the Threshold and Gain for Shivering

BACKGROUND:There are little data on the efficacy of antiemetics for treating postoperative nausea and vomiting (PONV) in patients who received prior PONV prophylaxis. METHODS:In this retrospective database analysis, we compared the efficacy of ondansetron with that of promethazine for treating PONV in adults receiving general anesthesia who failed ondansetron prophylaxis. RESULTS:Three thousand sixty-two patients received ondansetron and 752 received promethazine after failure of ondansetron prophylaxis. The complete response (no PONV and no further rescue) was 68% after administration of promethazine and 50% after ondansetron administration (P < 0.0001). There was no difference in complete response between 6.25 mg and higher doses of promethazine. CONCLUSIONS:Promethazine was significantly more effective than ondansetron for treating PONV after failed ondansetron prophylaxis. Promethazine 6.25 mg was as effective as higher doses.