High-flow Anesthesia Research Articles

Precision in practice: An audit study on low-flow anesthesia techniques with desflurane and sevoflurane for cost-effective and sustainable care.

In the backdrop of escalating healthcare costs and an increasing focus on resource optimization, this audit study delves into the realm of anesthesia management, specifically exploring the application of low-flow anesthesia (LFA). The primary objective was to assess adherence to hospital standards and evaluate the economic implications of LFA (<1 L/min). This retrospective audit focused on 700 adult patients undergoing elective surgeries with general anesthesia. Data sources included anesthesia records, electronic recording systems, and audits by a dedicated team. Fresh gas flow rates (FGFRs), minimum alveolar concentration (MAC), and volatile anesthetic consumption were analyzed. Cost comparisons between low-flow and high-flow anesthesia were conducted, employing specific cost per milliliter metrics. The average FGFR during the maintenance phase was found to be 0.45 ± 0.88 L/min. Adherence to hospital standards was notably high, with 94.29% of patients being maintained on low-flow gas rates. The differences in anesthetic consumption between low-flow and high-flow FGFR were statistically significant for both desflurane (12.17 ± 10.84 ml/MAC hour versus 43.12 ± 27.25 ml/MAC hour) and sevoflurane (3.48 ± 7.22 ml/MAC hour versus 5.20 ± 5.20 ml/MAC hour, P < 0.001). The calculated savings per patient with low-flow desflurane and sevoflurane anesthesia compared to high flow were found to be 109.25 AED and 6.74 AED, respectively. This audit advocates for the widespread adoption of LFA as a standard practice. Beyond aligning with hospital standards, the study highlights the multi-faceted benefits of LFA, encompassing economic savings, environmental safety, and enhanced patient care.

The Effect of Low-Flow versus High-Flow Anesthesia on Postoperative Cognitive Functions in Geriatric Patients Undergoing TUR-P Surgery

Introduction: This paper investigates the effect of low-flow anesthesia applications on postoperative cognitive function in geriatric age group (≥65 years old) patients who underwent elective transurethral resection of the prostate surgery. Materials and Method: A total of 98 patients aged 65 and over who underwent elective transurethral resection of the prostate surgery under general anesthesia between December 2021 and November 2022 in Hatay Mustafa Kemal University Research Hospital’s Department of Anesthesiology and Reanimation were included in the study. The patients were subjected to a mini mental test the day before the operation and postoperatively at six hours, one day, three days, and seven days. Visual analogue scale scores were evaluated at 3, 6, 12, 24, 48, and 72 hours. The data obtained were compared between the patient groups who underwent low-flow (1 L/min, n: 49) and high flow (4 L/min, n: 49) anesthesia. P&lt; 0.05 was considered statistically significant. Results: A comparison between the postoperative 6thhour, 1st day, 2nd day, 3rd day, and 7th day mini mental testing scores of the low-flow anesthesia and high flow anesthesia groups did not exhibit any notable variations (p: 0.668, 0.785, 0.745, 0.705, respectively). The visual analogue scale scores of the cases at 3, 6, 12, 24, 48, and 72 hours did not differ statistically according to the type of flow applied (p: 0.316, 0.925, 0.651, 0.548, 0.624, 0.466, respectively). Conclusion: It is thought that low-flow anesthesia can be applied safely, but it does not have a significant effect on cognitive functions compared to high flow anesthesia. Keywords: Anesthesia, General; Sevoflurane; Cognitive Dysfunction; Geriatrics.

High, Low, and Minimal Flow Anaesthesia Management: Effects on Oxygen Reserve Index and Arterial Partial Oxygen Pressure.

To determine the oxygen reserve index (ORI) as a supporting parameter to the arterial partial oxygen pressure (PaO2) in blood gases in hypoxia and hyperoxia monitoring with different fresh gas flows (FGF) in patients undergoing abdominal surgery. Randomised controlled trial. Place and Duration of the Study: Department of Anaesthesiology and Reanimation, Samsun Education and Research Hospital, Turkey, from January to September 2020. The study population of ninety patients was divided into three groups. After the high-flow period, the inspired oxygen fraction (FiO2) and flow-guided ventilation (FGF) were set to be 4 L/m and 40% in Group H (high-flow), 1 L/m and 50% in Group L (low-flow), and 0.5 L/m and 68% in Group M (minimal-flow), respectively. There was a very high statistically positive correlation between PaO2 and ORI in H, L, and M groups. When using a cut-off value of 0.005 for ORI for the detection of PaO2 >100 mmHg, the area under the curve (AUC) was 0.97 (p<0.001) with a sensitivity of 94.4% and specificity of 95.3%. The AUC was detected to be 0.95 in receiver operating characteristic (ROC) analysis when the hyperoxia cut-off value of ORI was used to determine PaO2 >150 mmHg in the estimation of hyperoxia. ORI can be used to complement SpO2 in low-flow anaesthesia in patients undergoing abdominal surgeries, provide guidance for PaO2, give information about tissue oxygen delivery, and contribute to the individualisation of oxygen therapy, and will therefore be included in the standard monitoring in the future. Anaesthesia, Index, Inhalation, Oxygen, Pressure, Surgery.

The effect of minimal and high flow anesthesia on optic nerve sheath diameter in laparotomic gynecological surgery

Background/Aim: Optic nerve sheath diameter (ONSD) is a surrogate parameter for intracranial pressure. This study evaluated the effect of anesthetics on ONSD in women undergoing surgery. We aimed to measure the effect of minimal and high flow anesthesia techniques on expiratory/inspiratory oxygen and carbon dioxide fraction values, hemodynamic parameters, and the optic nerve sheath diameter by ultrasonography in open gynecological surgeries.&#x0D; Methods: In the present prospective cohort study, 80 patients who planned laparotomic gynecological surgery were divided into two groups: a high flow of 2 L/min and a minimum flow of 0.5 L/min. Anesthesia was maintained with 50% oxygen-50% air at 2 L/min and desflurane at 1.1 MAC in Group 1 (n=40) and 50% oxygen-50% air at 0.5 L/min and desflurane at 1.1 MAC in Group 2 (n=40). After 10–15 min, group 2 was administered minimal flow with 50–60% oxygen and 40–50% air at 0.5 L/min desflurane, and 10 min before the end of the surgery, the patients were switched to high flow with 50% oxygen-50% air at 2 L/min.&#x0D; Results: Decreasing heart rates were higher in Group 2 (T0 P=0.001, T2 P=0.007, T3 P=0.035). There was a significant positive correlation between EtCO2 at the 60th min and optic nerve sheath diameter measurements in the minimal flow group (left ONSD r=0.440, P=0.004, right ONSD r=0.473, P=0.002). Although inspiratory oxygen values in Group 2 did not fall below 32%, it was lower than Group 1 except for the last measurement time.&#x0D; Conclusion: Minimal flow anesthesia is as safe as high flow in terms of effects on optic nerve sheath diameter and oxygenation parameters in laparotomic gynecological surgery.

THE EFFECTS OF MINIMAL, LOW AND HIGH FLOW ANESTHESIA ON BODY TEMPERATURE AND TISSUE OXYGENATION IN NASAL SURGERIES

OBJECTIVE: Intraoperative high fresh gas flow may cause Inadvertent perioperative hypothermia (IPH). For this reason, low and minimal flow anesthesia methods that improve the anesthesia climate are applied. We aimed to investigate the effects of minimal, low and high flow anesthesia on body temperature and tissue oxygenation in patients undergoing elective nasal surgery.MATERIAL AND METHODS: Prospective randomized controlled study included 92 patients aged 18-60 years, ASA1-2 operation time 1-4 hours, scheduled for elective nasal surgery under hypotensive anesthesia. The patients were divided into Group 1 (0.5Lmin-1), Group 2 (1Lmin-1) and Group 3 (2 Lmin-1). Demographic and operative data of the patients, preoperative waiting room temperature, intraoperative operating room temperature, intraoperative body temperature, anesthesia breathing circuit humidity and temperature, tissue oxygen saturation, 0th, 15th, 30th, 60th, 90th, 120th, 150thmin and postoperative shivering, Aldrete score, room temperature and body temperatures in the recovery unit were recorded.RESULTS: Perioperative hypothermia developed in all patients (p=0.001). Tympanic temperatures were similar in all three groups (p&amp;gt;0.05). In the subgroup comparison, it was found that the tissue oxygen saturation (StO2) 60 th min value of Group1 was higher than Group 2 (p=0.046). It was found statistically significant that the StO2 90 th min value of Group1 was higher than that of Group 2 and 3 (p=0.013, p=0.013). It was statistically significant that the StO2 120th min value of Group1 was higher than Group 3 (p=0.008).In Group1, postoperativeAldrete score was found to be significantly higher than the other two groups(p=0.002, p=0.002). A correlation was found between operating room temperature, postoperative recovery room temperature, and body temperature(r=.446, p&amp;lt;0.05;r=.531, p&amp;lt;0.01).CONCLUSIONS: Inadvertent perioperative hypothermia developed in all patients who underwent elective nasal surgery with hypotensive anesthesia in minimal, low and high flow anesthesia applications. It was observed that body temperatures, humidity and the temperature of the anesthesia period were similar in all groups. Tissue oxygen saturation was higher in the minimal flow anesthesia group and Aldrete score was higher in the postoperative recovery unit. Minimal flow anesthesia applications can be a good alternative to prevent IPH. However, we think that more studies are needed for the effects of low-flow anesthesia techniques at the tissue level.

Effects of different fresh gas flows on carboxyhemoglobin levels: non-invasive carbon monoxide monitoring: A randomized clinical trial.

To observe the effect of different fresh gas flows (FGF) on carboxyhemoglobin (COHb) levels non-invasively and continuously and to determine the contribution of the smoking status to intraoperative carbon monoxide (CO) accumulation and respiratory complications. A total of 64 patients were included in the study. Carboxyhemoglobin level was monitored non-invasively from the fingertip. Patients were divided into 2 according to the FGF as low-flow anesthesia (LFA; Group L) and high flow anesthesia (Group H). Each group was divided again into 2 groups as smokers and non-smokers. Carboxyhemoglobin and and the respiratory complications that occurred in the post-anesthesia care unit were recorded. The mean COHb values were significantly higher in Group L between 30th and 210th minutes. Furthermore, in Group L, intraoperative COHb levels were significantly higher in smokers compared to non-smokers in all periods. In group H, no difference was observed between smokers and non-smokers in terms of COHb levels after 60 minutes and also preoperative COHb levels of the patients developed respiratory complication was higher. If the CO2 absorbent is properly preserved in patients who are administered LFA, there will be no risk of CO accumulation even in chronic smokers.ClinicalTrials.gov REG. No.: NCT04832256.

The Effect of Sevoflurane Low-Flow Anesthesia on Preserving Patient Core Temperature

Introduction: Low-flow anesthesia (LFA) reduces the fresh gas flow (FGF) entering the anesthesia circuit and saves on the volatile agent used. In this study, the effect of LFA with sevoflurane on core temperature and the incidence of perioperative hypothermia were investigated. Methods: According to the FGF applied, patients were classified into three groups: LFA (1 L/min), medium-flow anesthesia (MFA = 2 L/min), and high-flow anesthesia (HFA = 4 L/min). Patients’ demographic data and the initial (T1) and final (T2) core temperatures during the operation were compared. Results: A total of 160 patients were included in the study. The T2 value of the HFA group was significantly lower than the LFA group (p = 0.028). Different flow values were found to have a significant effect on temperature change (F = 21.630, p < 0.001, partial eta squared = 0.216). There was a significant difference between the mean temperatures measured at two different times (F = 301.064, p < 0.001, partial eta squared = 0.657). The overall incidence of hypothermia was 32.5%, with 52 patients. Hypothermia (T²<36°C) incidences were not different between the LFA group and the MFA and HFA groups (p = 0.682). However, perioperative core temperature loss was significantly lower in the LFA group (p = 0.001). Conclusions: LFA using sevoflurane was not sufficient alone to significantly reduce the incidence of hypothermia. However, we have demonstrated that it may also have a beneficial effect on reducing perioperative temperature loss.

Evaluation of Oxygenation in Low- and High-Flow Anesthesia Applications by Oxygen Reserve Index: A Randomized Prospective Study

Evaluation of Oxygenation in Low- and High-Flow Anesthesia Applications by Oxygen Reserve Index: A Randomized Prospective Study

The effect of low flow anesthesia with sevoflurane on oxidative status: A prospective, randomized study.

Objectives:To assess the impact of low-flow, mid-flow, and high-flow sevoflurane anesthesia on the oxidative state by measuring thiol/disulfide levels in patients undergoing surgery.Methods:The study included 99 patients randomly assigned to 3 groups. In the low-flow anesthesia group, the fresh gas flow was diminished to 1 L.min-1 for anesthesia maintenance after 6 L.min-1 was administered for the first 10 minutes. In the mid-flow anesthesia group, fresh gas flow was applied as 2 L.min-1. In the high-flow anesthesia group, the fresh gas flow was administered as 4 L.min-1 throughout the operation. Blood samples were obtained before induction, at the 60th minute after induction, and at 2 hours postoperatively. Native thiol, total thiol, disulfide analyzed and disulfide/native thiol percentage, disulfide/total thiol percentage, and native thiol/total thiol percentage were calculated.Results:Disulfide values in mid-flow and low-flow anesthesia were significantly lower at the 60th minute after induction compared to the high-flow anesthesia group. In the group evaluations, intraoperative native thiol levels in the high-flow group were found to be substantialy lower than preoperative values.Conclusion:It was sighted that low-flow anesthesia with sevoflurane prohibited oxidative damage. It was concluded that low flow anesthesia can be utilized safely in this respect.

Effect of Fresh Gas Flow Rate on Thiol/Disulphide Hemostasis and Ischemia-modified Albumin in Laparoscopic Cholecystectomy.

To investigate the effects of low-flow and high-flow anesthesia techniques, administered with sevoflurane during laparoscopic cholecystectomy, on thiol/disulphide homeostasis and serum ischemia-modified albumin (IMA) levels. Double-blind, randomised study. Department of Anesthesiology and Reanimation, Health Science University, Bursa Yuksek Ihtisas Training and Education hospital, Bursa, Turkey from January to October 2020. Patients over the age of 18 years, scheduled for elective laparoscopic cholecystectomy, were included in the study. The patients were divided into two groups: Group 1 (low-flow, 1 L/min) and Group 2 (high-flow, 2 L/min). The blood samples for thiol/disulphide homeostasis and serum IMA levels were collected as follows: 5 minutes before induction of anesthesia (T0), 5 minutes after induction of anesthesia (T1) and postoperative 24th hour (T2). The final analysis included 104 patients. The two groups did not differ significantly in terms of any of the demographic characteristics (p >0.05). There were also no inter-group differences in terms of thiol/disulphide homeostasis parameters or serum IMA levels at T0, T1, or T2. However, in both groups, there were statistically significant changes in serum disulphide and IMA levels from T0 to T1 and T0 to T2 (p=0.000, and p=0.005, respectively). There was no difference between low-flow and high-flow anesthesia during laparoscopic cholecystectomy in terms of hemodynamics or thiol/disulphide homeostasis. Key Words: Low-flow anesthesia, High-flow anesthesia, Thiol/disulphide homeostasis, İschemia-modified albumin (IMA), Laparoscopic cholecystectomy.

Retrospective Evaluation of Anesthesia Experience at a Training and Research Hospital in Turkey

This study aims to evaluate retrospectively the two-year data of our clinic concerning the effects of training for reduced fresh gas flow anesthesia applications, the demographic data of patients, the types of anesthesia performed, non-operating room anesthesia applications and the incidences of admission to the post-anesthesia care unit. Hospital archives on anesthesia services of 2016-2017 were scanned. The acquired data were analyzed retrospectively with yearly comparisons on the bases of the consumed amount of inhalation anesthetics, distribution of the peripheral blocks according to the surgical sections, the number of patients operated outside the operating room and sent to the post-anesthesia care unit. The number of operations carried out in our hospital was 22533 in 2016 and 24634 in 2017. High flow anesthesia in 2016 and low flow anesthesia in 2017 were found statistically high (P &lt; 0.001). In 2016 and 2017, neuraxial block cases were used in 76.24% and 76.19% of the cesarean section, 4936and 7152 patients underwent anesthesia outside of the operating room; 405 and 816 patients were sent to the post-anesthesia care unit, respectively. In 2017, the consumption of inhalation agents decreased after regular training on the reduced fresh gas flow technique. In 2017, the increase observed in peripheral block applications was based on the increase in ultrasound experience in our clinic. We recommend a combination of reduced fresh gas flow with peripheral or neuraxial blocks to achieve multimodal general anesthesia.

Oxygen reserve index guided oxygen titration in one lung ventilation with low fresh gas flow

Continuous oxygen reserve index (ORI) measurement with multiple wave pulse co-oximetry is a noninvasive measurement. The decrease in the ORI trend provides a prediction for the development of hypoxemia and provides info rmation on hyperoxia. Our aim is to determine the effect of ORI-guided oxygen titration on hyperoxemia-mediated morbidity. Consecutive 120 ASA I-III patients, 18–70 years of age, without severe obstruction or restriction, undergoing one lung ventilation (OLV), were included in the study. Patients were divided into 4 groups. Oxygen titration without ORI monitoring with low-flow anesthesia (1 L/min, Group 1, n = 25) and high-flow anesthesia (4 L/min, Group 2, n = 28). Oxygen titration by ORI monitoring with low flow anesthesia (1 L/min, Group 3, n = 25) and high flow anesthesia (4 L/min, Group 4, n = 25). FiO2 increased up to 100% if necessary. OLV time, duration of surgery and anesthesia, FiO2 applied during OLV, oxygen application time (T) over 60%, vital signs, hospital and ICU stay time, and complications were recorded. There was a statistically significant difference in terms of FiO2 used during OLV (p < 0.05). There was no difference in ORI values (p < 0.05). In Group 3, both PaO2 and SpO2 were significantly lower than the others both before and during OLV. There was no significant difference in terms of ORI parameters between low flow and high flow anesthesia groups. There was a strong, positive correlation between the duration of hospital stay and FiO2 used above 80% during OLV. We concluded that ORI-guided thoracic anesthesia may reduce hospital stay and increase patient safety.

The effect of minimal-flow and high-flow hypotensive anesthesia on oxidative stress

Objective: The main objective of this study was to compare the effects of minimal and high gas flow-controlled hypotension applications on IMA and thiol/disulfide balance, which are indicators of oxidative stress.Methods: Patients undergoing elective tympanoplasty were randomized to two groups as minimal-flow and high-flow anesthesia groups. Minimal flow anesthesia was performed with 5L/min fresh gas flow reduced to 0.4 L/min. High flow was administered as 2 L/min fresh gas. Preoperative and intraoperative SpO2, StO2, EtCO2, mean arterial pressure and heart rate values were recorded. Preoperative and intraoperative IMA, total thiol, native thiol, disulfide, disulfide/native thiol and disulfide/total thiol values were recorded and compared between the two groups. Results: The mean intraoperative arterial pressure was statistically notably higher in the high flow group (p=0.048). The mean intraoperative SPO2 value was remarkably higher in the minimal flow group (p=0.032). The mean EtCO2 value was notably lower in the minimal flow group at 5 minutes and 15 minutes of the operation (p=0.029; p=0.048). The mean preoperative and intraoperative IMA values were statistically notably higher in the minimal flow group compared to the high flow group (for both, p=0.001). There was no remarkable difference between the groups in terms of the other monitored parameters (for all, p&amp;gt;0.05).Conclusion: IMA value was found to be significantly higher with minimal-flow anesthesia. However, no notable difference was found in terms of thiol/disulfide homeostasis, indicating the need for further comprehensive studies in order to draw a definitive conclusion

The effect of low flow anesthesia on hemodynamic and peripheral oxygenation parameters in obesity surgery.

Objectives:To investigate the effects of low-flow anesthesia on hemodynamic parameters and recovery from anesthesia in obese individuals undergoing laparoscopic surgery.Methods:This randomized-controlled and prospective study included 44 obese patients who underwent laparoscopic sleeve gastrectomy operation. The patients were randomly allocated into 2 groups as low-flow and high-flow anesthesia. Further, the groups compared in terms of hemodynamic parameters, anesthesia recovery times, operation times, and arterial blood gas parameters.Results:The groups were similar with respect to demographic data. Heart rate, peripheral oxygen saturation, arterial blood pressure measurements, end-tidal, and CO2, lactate levels measurements were similar in both groups during the entire procedure. There was also no statistically significant difference in terms of arterial blood gas parameters or anesthesia recovery periods.Conclusion:Low-flow anesthesia in laparoscopic obesity surgery seems to be safer compared to high-flow anesthesia in terms of the adequacy of tissue perfusion, depth of anesthesia, and postoperative recovery.

Randomized double-blind trial comparing effects of low-flow vs high-flow anesthesia on postoperative lung functions using respirometer.

Background and Aims:Modern anesthetic practice utilizes low-flow anesthesia with evolving evidence on its pulmonary effects. Studies comparing measurement of vital capacity and inspiratory reserve volume using respirometer in both low-flow and high-flow anesthesia are sparse. We evaluated the effects of low-flow and high-flow anesthesia on postoperative pulmonary functions using respirometer.Material and Methods:This was a prospective randomized double blind study wherein One hundred and ten patients undergoing peripheral surgeries under general anesthesia were allocated into two groups Group I- Low-flow anesthesia with O2 + N2O + Sevoflurane (0.5L + 0.5L + 3.5%) and Group II- High-flow anesthesia with O2 + N2O + Sevoflurane (2L + 2L + 2%). The difference in vital capacity (VC), inspiratory reserve volume (IRV), and peak expiratory flow rates (PEFR) from the preoperative period were compared in both the groups postoperatively.Results:The difference in VC, IRV, and PEFR measured in both the groups between the preoperative and postoperative period were found to be similar and statistically insignificant (P - 0.173, 1.00 and 0.213 respectively). The difference in single breath count (SBC), breath holding time (BHT), and respiratory rates (RR) were also similar in both the groups (P – 0.101, 0.698, and 0.467) respectively.Conclusions:The pulmonary effects of low-flow anesthesia are comparable with the high-flow ones in patients undergoing elective surgeries under general anesthesia.

Nasal High-Flow Oxygen and Total Intravenous Anaesthesia for Tubeless Airway Assessment and Surgery in Spontaneously Breathing Children

Nasal High-Flow Oxygen and Total Intravenous Anaesthesia for Tubeless Airway Assessment and Surgery in Spontaneously Breathing Children

LOW-FLOW ANESTHESIA TECHNIQUE REDUCES EMERGENCE AGITATION IN PEDIATRIC PATIENTS UNDERWENT GENERAL ANESTHESIA

Objectives: This study was designed to see the risk factors that contribute to emergence agitation (EA) and also to know the effectiveness of low-flow (LF) anesthesia technique in EA in pediatric patients.&#x0D; Methods: A total of 200 pediatric patients aged 6 months–6 years underwent surgery with general anesthesia were divided into two groups. The high-flow (HF) group was maintained with 5 l fresh gas flow (FGF), and the LF group was maintained with 500 ml FGF. The outcome was measured after the surgery was completed on Face, Legs, Activity, Cry, and Consolability and pediatric anesthesia emergence delirium (PAED) scores. Agitation defined in PAED score ≥10, and no agitation defined in PAED score &lt;10.&#x0D; Results: EA incidence in the HF group was higher compared to the LF group (59.5 vs. 4.7%, p&lt;0.001). HF anesthesia technique was a single risk factor for agitation event, whereas LF anesthesia may prevent EA incidence until up to 92.7%.&#x0D; Conclusion: LF anesthesia reduced agitation incidences. The effectiveness of LF was 92.7% in reducing the incidence of agitation. HF anesthesia was the main risk factor for agitation incidences.

Comparison of the Effects of Minimal and High-Flow Anaesthesia on Cerebral Perfusion During Septorhinoplasty.

The aim of this study was to analyse the effects of minimal-and high-flow anaesthesia on cerebral oxygenation during septorhinoplasty with controlled hypotension using near-infrared spectroscopy. Eighty patients scheduled for septorhinoplasty under general anaesthesia with controlled hypotension were randomised into two groups: minimal-flow (MF) or high-flow (HF). Both groups received desflurane anaesthesia to maintain bispectral index values at 40%-50% and 0.25-0.5 μg kg-1 min-1 i.v. remifentanyl infusion to maintain mean arterial blood pressure between 55 and 65 mmHg. The MF group received 5 L min-1 of fresh gas flow for the first 10 mins then the gas flow was reduced 0.4 L min-1. The HF group received 2 L min-1 of fresh gas flow throughout. Haemodynamic parameters and cerebral oxygen saturation were measured. There were no statistical differences in demographic variables, duration of anaesthesia and surgery, time to extubation and proceeding to an Aldrete score of 9. There were no statistical differences in haemodynamic parameters, end-tidal CO2 and cerebral oxygen saturation. The amount of desflurane used in the MF group was significantly lower than that used in the HF group (30.5±9.8 mL vs. 48.5±12.1 mL; p<0.05). MF and HF anaesthesia did not lead to any difference in cerebral oxygen saturation in patients undergoing septorhinoplasty with controlled hypotension. MF anaesthesia may thus be used as safely as HF anaesthesia is.

A randomised prospective comparison of equilibration point and changing gas composition during low-flow anaesthesia with sevoflurane vs desflurane.

Background and Aims:Safety and economy are the main concerns while using low- flow anaesthesia with newer inhalational agents. The main objective of this study was to use and compare 'equilibration time' of sevoflurane and desflurane after change-over from high-to-low flow anaesthesia.Methods:This prospective study included consenting adult patients between 18–70 years undergoing elective surgery under general anaesthesia. Patients were randomised initially to receive high-flow anaesthesia with 1.3 MAC of either desflurane or sevoflurane with nitrous oxide. After equilibration point, low-flow anaesthesia was initiated. Heart rate, non-invasive blood pressure, pulse oximeter, 5 electrode ECG and gas monitoring was done. Statistical analysis was done with the help of Med CalC version 12.5.0.0 (student version) and IBM SPSS Version 20.0.Results:Mean equilibration time in sevoflurane group was higher (4.59 ± 0.77 minutes) than desflurane group (3.78 ± 0.56 minutes, P < 0.001). Inspired concentrations of both inhalational agents varied from their vaporiser settings over 2 hours, more so with sevoflurane than desflurane. Inspired oxygen concentration (FiO2) remained above 30% during anaesthesia in both groups with stable haemodynamics.Conclusion:Change-over from high-to-low flow anaesthesia is faster in desflurane. With fresh gas flow (FGF) of 1 L with 50% oxygen and dial concentration of 1–1.5% of sevoflurane and 3.8–4.4% of desflurane, the risk of hypoxia is minimal. The disparity between the set and delivered concentrations is more (20%) in sevoflurane than desflurane (12%).

Evaluation of Low and High Flow Anesthesia Methods' Effects on Perioperative Hemodynamics, Depth of Anesthesia and Postoperative Recovery in Patients Undergoing Abdominal Surgery

Objective: The safe implementation of low-flow anesthesia has greatly facilitated, because of the anesthesia machines monitors that analyze the anesthetic gas composition detailed way, increase the knowledge of anesthetics. In this research; we aimed to compare the effects of high and low-flow general anesthesia methods on the peroperative hemodynamics, anesthesia depth and postoperative recovery time in patients with abdominal surgery in the presence of bispectral index monitoring. Methods: ASA I-II, 40 patients; 18 - 75 ages, who will have abdominal surgery were randomly divided into two groups, after the approval of the ethics committee (2016 - 06/02) and the patients. Anesthesia induction was performed with 6 mg/kg thiopental sodyum, 1 μg/kg remifentanil and 0.5 - 20 μg/kg/min remifentanil infusion, 4 - 6% desflurane after routine ECG, blood pressure, SpO2 and BIS monitorization to all patients. In the low-flow group after the first 10 min 4 lt/min fresh flow, the flow was reduced to 1 lt/min. Values of the heart rate, MBP, SpO2, FiO2, BIS, tympanic temperature at before induction and after intubation and the minutes of 15th, 30th, 45th, 60th, 90th,120th are recorded. Lactate and COHb values were measured in blood gas analyzes performed at 30th and 90th minutes. Results: When SpO2 and FiO2 values measured in different time periods of the individuals in both two groups were compared, differences between the minutes of 30th, 45th, 60th, 90th, 120th were significant. Conclusion: In this research; it is revealed that low-flow anesthesia which has advantages in many aspects can be used safely like high flow anesthesia when applied with adequate information equipment, appropriate anesthesia devices and necessary monitorizations.