The intraoperative glycemic response to intravenous insulin during noncardiac surgery: a subanalysis of the DeLiT randomized trial.

Patient characteristics may affect patients' response to insulin. We examined the impact of body weight and presence of diabetes on the response to insulin during noncardiac surgery. We studied 202 patients who were enrolled in the DeLiT Trial and received intraoperative intravenous insulin. Univariable and multivariable analyses (Bonferroni corrected) assessed the relationship between patient's response to the initial intraoperative I.V. bolus of regular insulin and the factors of interest. Blood glucose concentrations decreased 8.3 ± 10mg/dL (0.46 ± 0.56mmol/L) per unit of I.V. insulin in 30minutes. The response to insulin was similar in patients with or without diabetes (adjusted mean difference [97.5% confidence interval], 0.2 [-3.9, 4.2] mg/dL, 0.01 [-0.22, 0.24] mmol/L; P = .93). No relationship was found between insulin response and body weight (P=0.38). Our results suggest that adjustment for body weight and the presence of diabetes may not improve intraoperative insulin treatment algorithms.

Thoracic paravertebral regional anesthesia improves analgesia after breast cancer surgery: a randomized controlled multicentre clinical trial.

BACKGROUND: The contribution of regional anesthesia with thoracic paravertebral blockade to postoperative analgesia remains unclear. We compared the effect of a combination of paravertebral blockade and propofol general anesthesia (GA) with sevoflurane GA and opioid analgesia on postoperative pain and opioid use for patients undergoing breast cancer surgery. METHODS: Patients having breast cancer surgery were randomly assigned to paravertebral analgesia with propofol GA (PPA, n = 187) or sevoflurane GA with perioperative opioid analgesia (SOA, n = 199). The PPA and SOA groups were compared for opioid consumption and pain outcomes (on a 0-10 visual analogue scale [VAS]) at two hours postoperatively using superiority and inferiority statistics. We compared our results with previous publications in a meta-analysis. RESULTS: Compared with the SOA group, the PPA group experienced reduced median [interquartile range] pain VAS scores (1 [1,3] vs 2.5 [1,4], respectively; median difference -1.0; 99% confidence intervals [CI]: -1.5 to -0.5) and required less intraoperative fentanyl (50 [0, 125] µg vs 200 [100, 300] µg, respectively; median difference -100; 99% CI: -150 to -100) and less long-acting opioid (0 [0, 0] mg vs 3.0 [0, 12] mg, respectively, morphine equivalents; median difference -3; 99% CI: -4 to -2). Thus, non-inferiority was detected for all the above outcomes, and superiority tests for each outcome were highly significant in the expected directions (P < 0.001). Meta-analysis, including the current study, estimated a reduction in worst pain of 2.3 points (95% CI: 1.8 to 2.8) on a 0-10 scale and a 72% reduction (95% CI: 42 to 87) in mean opioid consumption in the immediate two postoperative hours for PPA vs SOA. CONCLUSION: Our results were largely consistent with previous much smaller studies. Compared with sevoflurane GA with opioid analgesia, the combination of paravertebral analgesia with propofol GA provides an early clinical analgesic benefit in females having breast cancer surgery. This analysis is a substudy of an ongoing multicentre double-blinded randomized trial ( www.clinicaltrials.gov , NCT00418457) of cancer recurrence.

An evaluation of a zero-heat-flux cutaneous thermometer in cardiac surgical patients.

BACKGROUND: Although core temperature can be measured invasively, there are currently no widely available, reliable, noninvasive thermometers for its measurement. We thus compared a prototype zero-heat-flux thermometer with simultaneous measurements from a pulmonary artery catheter. Specifically, we tested the hypothesis that zero-heat-flux temperatures are sufficiently accurate for routine clinical use. METHODS: Core temperature was measured from the thermistor of a standard pulmonary artery catheter and with a prototype zero-heat-flux deep-tissue thermometer in 105 patients having nonemergent cardiac surgery. Zero-heat-flux probes were positioned on the lateral forehead and lateral neck. Skin surface temperature probes were attached to the forehead just adjacent to the zero-heat-flux probe. Temperatures were recorded at 1-minute intervals, excluding the period of cardiopulmonary bypass, and for the first 4 postoperative hours. Zero-heat-flux and pulmonary artery temperatures were compared with bias analysis; differences exceeding 0.5°C were considered to be potentially clinically important. RESULTS: The mean duration in the operating room was 279 ± 75 minutes, and the mean cross-clamp time was 118 ± 50 minutes. All subjects were monitored for an additional 4 hours in the intensive care unit. The average overall difference between forehead zero-heat-flux and pulmonary artery temperatures (i.e., forehead minus pulmonary artery) was -0.23°C (95% limits of agreement of ±0.82); 78% of the differences were ≤0.5°C. The average intraoperative temperature difference was -0.08°C (95% limits of agreement of ±0.88); 84% of the differences were ≤0.5°C. The average postoperative difference was -0.32°C (95% limits of agreement of ±0.75); 84% of the differences were ≤0.5°C. Bias and precision values for neck site were similar to the forehead values. Uncorrected forehead skin temperature showed an increasing negative bias as core temperature decreased. CONCLUSIONS: Core temperature can be noninvasively measured using the zero-heat-flux method. Bias was small, but precision was slightly worse than our designated 0.5°C limits compared with measurements from a pulmonary artery catheter.

A time-motion economic analysis of postoperative nausea and vomiting in ambulatory surgery.

BACKGROUND: One-third of surgical outpatients experience postoperative nausea and vomiting (PONV) during their hospital stay or post-discharge nausea and vomiting (PDNV) after hospitalization. We determined the incremental costs of PONV/PDNV in ambulatory patients with this time-and-motion study. METHODS: In 100 ambulatory surgery patients, we evaluated the incidence of PONV, time staff spent with patients, use of PONV-related supplies, recovery duration, PONV rescue treatments, and quality-of-life through to the third postoperative morning. Patients with and without PONV/PDNV were compared in relation to PONV-related cost after adjusting for age, American Society of Anesthesiologists status, body mass index, and duration and complexity of surgery. RESULTS: Thirty-seven percent of the patients experienced PONV during hospitalization; this increased to 42% by the first postoperative morning and increased further to 49% by the third postoperative morning. Patients with PONV spent one hour longer in the postanesthesia care unit than patients without PONV (median [interquartile range] 234 [188-287] min vs 171 [144-212] min, respectively; P = 0.001). The amount of nursing time required for patients with PONV was significantly greater than that required for patients without PONV (82 [63-106] min vs 68 [57-79] min, respectively; P = 0.02). The total cost of postoperative recovery was significantly greater for patients with PONV/PDNV than for those without (US$730 vs $640, respectively; P = 0.006). Postoperative nausea and vomiting/PDNV was associated with an adjusted incremental total cost of $75 (95% confidence interval $67 to $86). Postoperative nausea and vomiting was also associated with worsened postoperative quality of life (49% of patients with PONV/PDNV rated quality high in four domains vs 94% of patients without PONV/PDNV; P < 0.001). CONCLUSION: Postoperative nausea and vomiting/PDNV were common; they impaired quality of life and imposed an incremental cost of $75 per patient. This incremental cost is comparable with the cost patients are willing to pay to avoid PONV.

Elevated catecholamines and hepatic artery vasospasm in porcine small-for-size liver graft.

BACKGROUND: Elevated levels of norepinephrine (NE) have been reported in recipients of small-for-size liver (SFS) grafts in the perioperative period. The aim of the study is to test the hypothesis that although circulating catecholamines are elevated in recipients of SFS grafts, they are not the primary agents responsible for the hepatic artery (HA) vasospasm. METHODS: Female porcine recipients receiving a 20% (n = 10) partial liver graft were compared with a control group, using 60% partial liver transplanted grafts (n = 9). Hepatic blood flow (PVF, HAF) and levels of plasma catecholamines (epinephrine and NE) were measured at designated time points through postoperative day (POD) 7. Phentolamine (PA), an α-adrenergic blocker, was administered at doses of 1 to 112.5 ug/kg/min through an indwelling HA to the recipients of 20% group on POD1 (n = 5). RESULTS: In the 20% group following reperfusion, HA vasospasm was found at 10, 60, and 90 min, and persisted on POD 3 and POD 7. Plasma NE levels increased after reperfusion in 20% and 60% groups and peaked at 6 h with 10- to 13-fold increased levels compared with baseline. In the 20% group, NE levels remained elevated up to POD 7. PA infusion at low (1-10 ug/kg/min) and high (12.5-112.5 ug/kg/min) doses did not reverse the reduced HAF observed in 20% group recipients. CONCLUSION: Elevated serum NE does not appear to be the primary factor mediating HA vasospasm in the porcine SFS graft.