Reflection Versus Rebreathing for Administration of Sevoflurane During Minor Gynecological Surgery.

BACKGROUND: Contemporary anesthetic circle systems, when used at low fresh gas flows (FGF) to allow rebreathing of anesthetic, lack the ability for rapid dose titration. The small-scale anesthetic reflection device Anaesthetic Conserving Device (50mL Version; AnaConDa-S) permits administration of volatile anesthetics with high-flow ventilators. We compared washin, washout, and sevoflurane consumption using AnaConDa-S versus a circle system with low and minimal FGF. METHODS: Forty patients undergoing breast surgery were randomized to receive 0.5 minimal alveolar concentration (MAC) sevoflurane with AnaConDa-S (21 patients, reflection group) or with a circle system (low flow: FGF = 0.2 minute ventilation [V'E], 9 patients; or minimal flow: 0.1 V'E, 10 patients). In the reflection group, syringe pump boluses were given for priming and washin; to simulate an open system, the FGF of the anesthesia ventilator was set to 18 L·min-1 with the soda lime removed. In the other groups, the FGF was increased for washin (1 V'E for 8 minutes) and washout (3 V'E). For all patients, tidal volume was 7 mL·kg-1 and the respiratory rate adjusted to ensure normoventilation. Analgesia was attained with remifentanil 0.3 µg·kg-1·min-1. Sevoflurane consumption was compared between the reflection group and the low- and minimal-flow groups, respectively, using a post hoc test (Fisher Least Significant Difference). To compare washin and washout (half-life), the low- and minimal-flow groups were combined. RESULTS: Sevoflurane consumption was reduced in the reflection group (9.4 ± 2.0 vs 15.0 ± 3.5 [low flow, P < .001] vs 11.6 ± 2.3 mL·MAC h-1 [minimal flow, P = .02]); washin (33 ± 15 vs 49 ± 12 seconds, P = .001) and washout (28 ± 15 vs 55 ± 19 seconds, P < .001) times were also significantly shorter. CONCLUSIONS: In this clinical setting with short procedures, low anesthetic requirements, and low tidal volumes, AnaConDa-S decreased anesthetic consumption, washin, and washout times compared to a circle system.

Impact of intraoperatively salvaged and washed blood on stimulated cytokine release in vitro.

BACKGROUND: Intraoperative blood salvage and processing it with commercially available devices is a widespread standard procedure to reduce allogeneic blood transfusion in patients undergoing major orthopedic surgery. The aim of this study was to investigate the impact of such processed blood on the immune system by measuring pro- and anti-inflammatory cytokines. STUDY DESIGN AND METHODS: Salvaged blood from 20 patients undergoing hip arthroplasty was processed with a continuous autotransfusion system. One part of the processed blood was left without further treatment, one part was additionally leukoreduced, one part was irradiated, and one part was separated into its cellular and soluble fraction by centrifugation. Specimens from each part were mixed in vitro with venous blood from the patient in ratios of 3:1, 1:1, and 1:3 and incubated with endotoxin for 24 hours. Tumor necrosis factor (TNF)-α and interleukin (IL)-10 were measured in cell culture supernatants by enzyme-linked immunosorbent assay. RESULTS: All parts of the salvaged blood were without a significant influence on TNF-α release. In contrast, IL-10 was significantly increased, independently of the admixtured salvaged blood being plain, additionally irradiated, or additionally leukoreduced. This IL-10 increase was also found with the cellular fraction of the plain salvaged blood, whereas the soluble fraction had no influence on IL-10 release. CONCLUSION: Intraoperative salvaged blood is not immunologically inert. We observed a significant increase in the anti-inflammatory IL-10 response without affecting the proinflammatory TNF-α release. Neither leukofiltration nor gamma irradiation eliminated this effect that was limited only to the cellular fraction of the salvaged blood, suggesting red blood cells to be responsible for the observed immunomodulation.

Postoperative Pain Therapy with Laser Acupuncture after Cesarean Section under Spinal Anesthesia: A Double-Blinded, Randomized, Placebo-Controlled Trial.

PURPOSE: The aim of our prospective, randomized, double-blind, placebo-controlled study was to investigate the effect of laser acupuncture on postoperative pain in women undergoing cesarean section. METHODS: 99 women (mean age 32 ± 5 years) scheduled for cesarean section under spinal anesthesia at Saarland University Hospital Medical Center, Homburg (Germany) were enrolled in this trial after giving written consent. Patients were randomized in two groups receiving a course of 3 treatments over 3 days with either active or placebo laser. Each acupuncture session treated Di-4 and Shen-men of both hands and ears. Primary outcome was defined as the pain severity at rest measured by Numeric Rating Scale (NRS) on the first postoperative day. Secondary outcome measures included analgesic consumption, time to mobilization, and length of stay. Treatment occurred on the operation day and on the following 2 days. Data were collected by a standardized questionnaire. RESULTS: From 95 included patients, 80 were analyzed. No statistical difference between both groups were observed for pain severity at rest on the first postoperative day after cesarean section (Mann-Whitney U test, p = 0.850, verum group [mean ± standard deviation]: 3.3 ± 2.1 vs. placebo group: 3.2 ± 1.9). Secondary outcome measures regarding analgesic consumption showed no difference in NSAID or opioid between treatment and placebo group. Laser acupuncture showed no effect on time to mobilization and length of stay. CONCLUSION: Our study could not demonstrate significant effects by the application of laser acupuncture on postoperative pain in women undergoing cesarean section.