Feasibility, safety, and economic consequences of using minimal flow anaesthesia by Maquet FLOW-i equipped with automated gas control.

Low fresh gas flow rates are recommended because of their benefits, however, its use is limited due to associated risks. The main purpose of this study was to investigate whether 300 mL of fresh gas flow that practised with automated gas control mode is applicable and safe. The second aim is to show that automated mode can provide economic benefits. Sixty hepatectomy cases who suitable criterias were included to cohort study in three groups as prospective, sequential, observational. An operating room were allocated only for this study. 300 mL fresh gas flow with automated mode (groupA3), 600 mL fresh gas flow with automated mode (groupA6) and, 600 mL fresh gas flow with manually (groupM6) was applied. Patients' respiratory, hemodynamic parameters (safety), number of setting changes, O2 concentration in the flowmeter that maintained FiO2:0.4 during the low flow anaesthesia (feasibility) and comsumption data of anaesthetic agent and CO2 absorber (economical) were collected and compared. p < 0.05 was accepted as statistical significance level. No significant differences were detected between the groups in terms of demographic data and duration of operation. Safety datas (hemodynamic, respiratory, and tissue perfusion parameters) were within normal limits in all patients. O2 concentration in the flowmeter that maintained FiO2:0.4 was statistically higher in groupA3 (92%) than other groups (p < 0.001) but it was still within applicable limits (below the 100%). Number of setting changes was statistically higher in groupM6 than other groups (p < 0.001). The anaesthetic agent consumption was statistically less in groupA3 (p = 0.018). We performed fresh gas flow of 300 mL by automated mode without deviating from the safety limits and reduced the consumption of anaesthetic agent. We were able to maintain FiO2:0.4 in hepatectomies without much setting changes, and we think that the automated mode is better in terms of ease of practise.

Feasibility, safety, and economic consequences of using low flow anesthesia according to body weight.

BACKGROUND: Low flow anesthesia (LFA) provides a saving up to 75% and improves the dynamics of inhaled anesthesia gas, increases mucociliary clearance, maintains body temperature, and reduces water loss. LFA has been recommended for anesthesiologists in recent years to avoid high fresh gas flow (FGF). However, LFA use is limited due to associated risks. The main purpose of this study was to investigate whether LFA according to body weight, which is the main determinant of oxygen requirement, is feasible and safe in the normoxia range. The second aim was to show that this method can provide economic benefit. METHODS: Eighty donor hepatectomy cases were included to study in two groups as prospective, observational. A surgery room and a team were allocated only for this study. Considering the oxygen requirement (approximately 3-3.5 mL/kg/min), for the first 40 cases, 10 mL/kg (group 10) FGF was applied; for the second 40 cases, 20 mL/kg (group 20) was applied. Desflurane (Suprane©) was used as an inhalation agent, and analgesia was achieved with remifentanil infusion. Patients' demographic, respiratory, hemodynamic, and tissue perfusion parameters (SpO2 and NIRS), and comsumption data (anesthetic agent and CO2 absorbent) were collected and compared. RESULTS: No significant differences were detected between the groups in terms of demographic data, duration of surgery, and hemodynamic, respiratory, and tissue perfusion parameters. These parameters were within normal limits in all patients at all times. The maximum O2 concentration in the FGF that maintained FiO2:0.4 and provided adequate oxygenation during the LFA was 61% (min 56%; max 67%) in group 10, and 47% (min 43%; max 51%) in group 20. The hourly anesthetic agent consumption was significantly different in group 10 than in group 20 (12.4 ± 4 mL vs. 21.5 ± 8 mL/h, respectively (p < 0.001). CONCLUSIONS: We performed 10 mL/kg FGF speed without deviating from the safety limits to be FiO2:0.4 in donor hepatectomies, reducing the total costs 38% compared with 20 mL/kg FGF.

Effect of transversus abdominis plane block in combination with general anesthesia on perioperative opioid consumption, hemodynamics, and recovery in living liver donors: The prospective, double-blinded, randomized study.

BACKGROUND: Transversus abdominis plane (TAP) block provides effective postoperative analgesia after abdominal surgeries. It can be also a useful strategy to reduce perioperative opioid consumption, support intraoperative hemodynamic stability, and promote early recovery from anesthesia. The aim of this prospective randomized double-blind study was to assess the effect of subcostal TAP blocks on perioperative opioid consumption, hemodynamic, and recovery time in living liver donors. METHODS: The prospective, double-blinded, randomized controlled study was conducted with 49 living liver donors, aged 18-65 years, who were scheduled to undergo right hepatectomy. Patients who received subcostal TAP block in combination with general anesthesia were allocated into Group 1, and patients who received general anesthesia alone were allocated into Group 2. The TAP blocks were performed bilaterally by obtaining an image with real-time ultrasound guidance using 0.5% bupivacaine diluted with saline to reach a total volume of 40 mL. The primary outcome measure in our study was perioperative remifentanil consumption. Secondary outcomes were mean blood pressure (MBP), heart rate (HR), mean desflurane requirement, anesthesia recovery time, frequency of emergency vasopressor use, total morphine use, and length of hospital stay. RESULTS: Total remifentanil consumption and the anesthesia recovery time were significantly lower in Group 1 compared with Group 2. Postoperative total morphine use and length of hospital stay were also reduced. Changes in the MAP and HR were similar in the both groups. There were no significant differences in HR and MBP between groups at any time. CONCLUSIONS: Combining subcostal TAP blocks with general anesthesia significantly reduced perioperative and postoperative opioid consumption, provided shorter anesthesia recovery time, and length of hospital stay in living liver donors.

Accuracy of non-invasive hemoglobin monitoring by pulse CO-oximeter during liver transplantation.

BACKGROUND: Hemoglobin level monitoring is essential during liver transplantation (LT) due to substantial blood loss. We evaluated the accuracy of non-invasive and continuous hemoglobin monitoring (SpHb) obtained by a transcutaneous spectrophotometry-based technology (Masimo Corporation, Irvine, CA) compared with conventional laboratory Hb measurement (HbL) during LT. Additionally, we made subgroup analyses for distinct surgical phases that have special features and hemodynamic problems and thus may affect the accuracy of SpHb. METHODS: During LT, blood samples were obtained twice for each of the three phases of LT (pre-anhepatic, anhepatic, and neohepatic) and were analyzed by the central laboratory. The HbL measurements were compared with SpHb obtained at the time of the blood draws. RESULTS: A total of 282 data pairs obtained from 53 patients were analyzed. The SpHb values ranged from 6.9 to 17.7 g/dL, and the HbL values ranged from 5.4 to 17.1 g/dL. The correlation coefficient between SpHb and HbL was 0.73 (P<0.001), and change in SpHb versus change in HbL was 0.76 (P<0.001). The sensitivity value determined using a 4-quadrant plot was 79%. The bias and precision of SpHb to HbL were 0.86±1.58 g/dL; the limits of agreement were -2.25 to 3.96 g/dL. The overall correlation between SpHb and HbL remained stable in different phases of surgical procedure. CONCLUSIONS: SpHb was demonstrated to have a clinically acceptable accuracy of hemoglobin measurement in comparison with a standard laboratory device when used during LT. This technology can be useful as a trend monitor during all surgical phases of LT and can supplement HbL to optimize transfusion decisions or to detect occult bleeding.

The effects of dexmedetomidine on liver ischemia-reperfusion injury in rats.

BACKGROUND: Ischemia-reperfusion (IR) injury of the liver may cause various types of damage to hepatic tissues. It can affect the prognosis of patients and the success of an operation. Dexmedetomidine is a selective α2 receptor agonist. We investigated whether dexmedetomidine provides protection against IR-induced liver injury in rats. METHODS: Forty rats were divided equally into four groups. In group 1, the liver was manipulated after the laparotomy, and no occlusion of the vessels of the liver was performed. In group 2, once the abdomen was opened, 60 min of ischemia and 60 min of reperfusion were applied according to the segmental hepatic ischemia model. In group 3, 10 µg/kg of dexmedetomidine was injected into the peritoneal cavity 30 min before ischemia. In group 4, 100 µg/kg of dexmedetomidine was injected into the peritoneal cavity 30 min before ischemia. Further procedures in groups 3 and 4 were the same as those of group 2. After the experiment was completed, the rats were killed. Liver tissues were removed and stored until biochemical and histologic assessments were performed. RESULTS: The malondialdehyde level in group 2 was higher than that of groups 1, 3, and 4 (P = 0.001, P = 0.000, and P = 0.000, respectively). Superoxide dismutase, catalase, and glutathione levels in group 2 were lower than those in group 1 (P = 0.001, P = 0.027, and P = 0.014, respectively). Superoxide dismutase and catalase levels in group 4 were higher than those in group 2 (P = 0.002 and P = 0.000, respectively). GSH levels in groups 3 and 4 were higher than those in group 2 (P = 0.049 and P = 0.006, respectively). A lower glutathione peroxidase level was detected in groups 2 and 3 than that in group 1 (P = 000). Group 4 demonstrated an increase in glutathione peroxidase levels compared with group 3 (P = 0.014). The histologic injury scores in groups 2-4 were higher than those in group 1 (P = 0.003, P = 0.002, and P = 0.001, respectively). However, the histologic injury scores were lower in groups 3 and 4 than those in group 2 (P = 0.003 and P = 0.002, respectively). CONCLUSIONS: This study showed that dexmedetomidine may protect the liver against IR injury in rats.

Comparison of the effects of desflurane and sevoflurane on the expression of platelet surface glycoproteins in unstimulated and adenosine diphosphate-induced platelets in vitro.

STUDY OBJECTIVE: To compare the effects of one minimum alveolar concentration (MAC) desflurane and sevoflurane on the expression of CD42b (glycoprotein [GP] Ib), CD41 (GPIIb), CD61 (GPIIIa), CD62P (P-selectin), and CD63 in both unstimulated and adenosine diphosphate (ADP)-stimulated platelets in vitro. SETTING: University laboratory. SUBJECTS: 15 healthy volunteers. INTERVENTIONS: Platelet-rich plasma was obtained and divided into three groups: platelet-rich plasma exposed to air (group 1); air plus one MAC desflurane (6% vol; group 2), and air plus one MAC sevoflurane (2% vol; group 3), for 40 minutes. Percentage of antigen-positive cells (%(+)) mean channel fluorescence (MCF(Sigma)), and index of platelet activation for positive platelets (IPA(+)) as expression markers for GPIb, GPIIb, GPIIIa, P-selectin, and CD63, were measured. MEASUREMENTS AND MAIN RESULTS: In unstimulated platelets, expression markers for GPIIb and GPIIIa were significantly lower in groups 2 and 3 than group 1 (P < 0.001). P-selectin expression markers were significantly higher in group 2 than in group 1 or group 3 (P < 0.016). CD63 expression markers were significantly lower in group 3 than group 1 (P < 0.016). In ADP-stimulated platelets, expression markers for all glycoproteins were significantly higher in all groups. CONCLUSION: Neither one MAC desflurane nor sevoflurane showed any significant change in ADP-stimulated platelets compared with the control group.

A comparison of the sedative, hemodynamic, and respiratory effects of dexmedetomidine and propofol in children undergoing magnetic resonance imaging.

We compared the sedative, hemodynamic, and respiratory effects of dexmedetomidine and propofol in children undergoing magnetic resonance imaging procedures. Sixty children were randomly distributed into two groups: The dexmedetomidine (D) group received 1 microg/kg initial dose followed by continuous infusion of 0.5 microg.kg(-1).h(-1) and a propofol group (P) received 3 mg/kg initial dose followed by a continuous infusion of 100 microg.kg(-1).min(-1). Inadequate sedation was defined as difficulty in completing the procedure because of the child's movement during magnetic resonance imaging. Mean arterial pressure (MAP), heart rate, peripheral oxygen saturation, and respiratory rate (RR) were recorded during the study. The onset of sedation, recovery, and discharge time were significantly shorter in group P than in group D. MAP, heart rate, and RR decreased during sedation from the baseline values in both groups. MAP and RR were significantly lower in group P than in group D during sedation. Desaturation was observed in four children of group P. Dexmedetomidine and propofol provided adequate sedation in most of the children. We conclude that although propofol provided faster anesthetic induction and recovery times, it caused hypotension and desaturation. Thus, dexmedetomidine could be an alternative reliable sedative drug to propofol in selected patients.

Sevoflurane as an alternative anaesthetic for electroconvulsive therapy.

OBJECTIVES: The aim of this study was to investigate the effects of sevoflurane and propofol used in electroconvulsive therapy (ECT) on hemodynamic variables and duration of seizure activity and recovery profiles. METHODS: Sixteen patients who were not premedicated, with a mean age 27.1 years, were enrolled in this prospective open trial, receiving a total of 64 ECT treatments. Each patient was given the following 2 anesthetic regimens in random order: In group S, anesthesia was induced with 7% sevoflurane in 100% oxygen at 6 L min fresh gas flow until the loss of consciousness and 1.5 mg kg propofol in group P. Adequate muscle relaxation was achieved with suxamethonium, 1.0 - 1.2 mg kg. Noninvasive mean arterial pressure (MAP) and heart rate (HR) values, duration of motor seizure activity, and recovery times were recorded. RESULTS: The mean motor seizure duration was significantly longer with sevoflurane (mean [SD]: 43.09 [16.6] s) than with propofol (28.91 [7.9] s; P < 0.05). The MAP 1 minute and 10 minutes after ECT (101.25 [7.5] mm Hg and 100.16 [11.0] mm Hg, respectively) was significantly increased compared with before ECT (94.56 [6.9] mm Hg) in sevoflurane group (P < 0.05). Time to spontaneous breathing, eye opening and obeying commands, and changes in MAP and HR during and after ECT were similar in both regimens. CONCLUSION: Induction with 7% sevoflurane allows prolonged duration of motor seizures in ECT. We concluded that induction of anesthesia with sevoflurane inhalation is a reasonable alternative for patients undergoing ECT.