Low-flow Anesthesia Research Articles

Practice of Low Flow Anaesthesia and Volatile Agents Choices among Anaesthesia Providers at Muhimbili National Hospital and Muhimbili Orthopaedic Institute

With the availability of modern workstations and heightened awareness of the Health services cost and environmental effects of waste anaesthesia gases, anaesthesia providers worldwide are practicing low flow anaesthesia. In most developing countries Low Flow Anaesthesia is still underutilized due to lack of monitoring equipments and sufficient knowledge. Tanzania appears to have a paucity of studies on the prevailing practice pattern of fresh gas flow. Objective; The study aimed at assessing the practice of low flow anaesthesia and volatile agents choices among anaesthesia providers at Muhimbili national hospital and Muhimbili orthopaedic institute. Methods: A descriptive cross-sectional study was carried out for a period of 8 months involving 158 anaesthesia providers. A Structured questionnaire was used to collect data which included demographic, practice setting of Low Flow Anaesthesia, Workstations, scavenging, monitoring equipments, Volatile agents routinely used and preferred Agent. Data were analysed using the IBM Statistical package for social science’s version 23.0. Result: Prevalence of Low flow anaesthesia was 27.2%, however, only 6% used the fresh gas flow of 1l/min – 500mls/min. All anaesthesia providers had workstations and only 2.3% displayed Minimum Alveolar concentration (MAC), 79.1% worked in theatre with functioning scavenging systems, 55.8% used capnography, 6.9% monitored inspiratory Oxygen and none of anaesthesia providers used Bispectral and Agent Analyzers. Isoflurane was the most routinely used inhalational agents (100%) followed by Sevoflurane (69%), then Halothane (32%). Desflurane still not available in these hospitals. Conclusion: Low flow anaesthesia is seldom practiced in our locality despite having strong evidence of attractive advantages in medical practice and ergonomics.

Anesthesia and its environmental impact: approaches to minimize exposure to anesthetic gases and reduce waste.

In today's era of modern healthcare, the intersection between medical practices and environmental responsibility has gained significant attention. One such area of focus is the practice of anesthesia, which plays a crucial role in various surgical procedures. Anesthetics such as nitrous oxide and volatile halogenated ethers (desflurane, isoflurane, sevoflurane) are examples of medical gases that are strong greenhouse gases that contribute to global warming. During medical procedures, most of these anesthetic agents are released into the atmosphere, which exacerbates their influence on the environment. Also anesthesia delivery systems have traditionally utilized high flow rates of gases, leading to not only excessive consumption but also a considerable environmental impact in terms of greenhouse gas emissions. However, the emergence of low-flow anesthesia (LFA) presents a promising solution for achieving emission reduction and cost savings, thereby aligning healthcare practices with sustainability goals. Understanding LFA involves the administration of anesthetic gases to patients at reduced flow rates compared to conventional high-flow methods. This practice requires precision in gas delivery, often incorporating advanced monitoring and control systems. By optimizing gas flow to match the patient's requirements, LFA minimizes wastage and excessive gas release into the environment, subsequently curbing the carbon footprint associated with healthcare operations. Decreasing volatile anesthetic delivery provides safe and effective strategies for anesthesia providers to decrease costs and reduce environmental pollution. Current literature support in favor of LFA represents an area of cost containment and an opportunity to lessen the environmental impact of anesthesia. This article will cover the concept of LFA, the distinctions between low flow and minimal flow, and the potential advantages of LFA, such as those related to patient safety, the environment, and the economy.

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.

Anaesthetic gases and the environment: Is it time for a rethink?

BackgroundGeneral anaesthesia is in common use for patients undergoing surgical procedures, with the option of both inhalational and intravenous anaesthetic techniques. Anaesthetic gases are often excluded from discussions on sustainable healthcare delivery, despite being a significant contributor to the overall environmental impact of healthcare services. MethodsA literature review was carried out on previously published papers on the impact anaesthetic gases have on our environment and at ways to reduce their impact in current anaesthetic practice. The aim was to write a narrative review detailing the areas of concern as well as the current clinical situation in the European setting. Summary/conclusionsThe two classes of inhaled anaesthetic agent most frequently used are nitrous oxide and volatile agents (most commonly sevoflurane, isoflurane and desflurane). Both are recognised greenhouse gases that contribute to climate change.Minor modifications in the use of anaesthetic gases can have a significant environmental impact. These modifications include avoiding nitrous oxide whenever possible, avoiding desflurane (and using sevoflurane instead), using low flow anaesthesia during maintenance, swapping volatile-based anaesthesia for a TIVA technique when clinically appropriate and considering the use of central neuraxial or regional anaesthesia in place of general anaesthesia when possible.

Clinical assessment of recovery from neuromuscular blockers, is it a safe practise - An observational study

The incidence of residual neuromuscular paralysis (RNMB) with Train of four ratio&amp;#60;0.9 remains as high as 16% in PACU even after administration of reversal when neuromuscular monitoring is not done. Reversal with standard dose of neostigmine and extubation are done based on the clinical signs. We observed the clinical signs of neuromuscular recovery and correlated with neuromuscular monitoring to assess the degree of residual blockade in the post-operative period.100 Patients posted for surgery under general anaesthesia with endotracheal tube intubation and controlled ventilation were enrolled for the study after obtaining human ethical approval. Standard anaesthesia technique using morphine, propofol, vecuronium, isoflurane with low flow anaesthesia were administered for all patients. TOF was noted at the end of surgical procedure when patient resumed spontaneous respiration, during extubation, and at 15 minutes interval for one hour in the postoperative period. Hemodynamics were observed including respiratory rate. Overall 32 percent of patients had residual paralysis. 27% at 15 min, 26% at 30min, 6% at 45min and 3% at one hour in the postoperative period showed RNMB. Subgroup analysis showed that at the time administration of reversal 72 patients had (TOFR&amp;#62;0.4) and 28 had (TOFR&amp;#60;.0.4), showed significant difference in improvement in TOFR between 2 subgroups before reversal, immediate extubation and 15 min post extubation (p=0.00,0.001,0.003,) respectively. Clinical findings of neuromuscular reversal is not foolproof for complete recovery and standard dose neostigmine given during shallow block will accentuate the residual neuromuscular paralysis.

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.

Low Flow Anesthesia Benefits and Implementation in a Secondary Health Care Institute

Low Flow Anesthesia Benefits and Implementation in a Secondary Health Care Institute

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.

Retrospective investigation on equine low flow anaesthesia: economics and environment

Retrospective investigation on equine low flow anaesthesia: economics and environment

Sustainability Standards in Pediatric Anesthesia: Quality Initiative to Reduce Costly Environmentally Harmful Volatile Anesthetics

Background: The emission and entrapment of greenhouse gases (GHG) inside the atmosphere is one of the leading causes of global warming. Commonly administered anesthetics have global warming potential up to 2,000 times greater than carbon dioxide. This Quality Improvement (QI) initiative aimed to develop a set of sustainability standards to reduce volatile anesthetic GHG emissions and costs at a children’s hospital. Methods: In January 2020, the QI project team implemented education sessions for clinical staff on the environmental impact of volatile anesthetics, bedside clinical reminders, resource guides on sustainable anesthesia practices, preset low-flow gas levels on anesthesia machines, relocated and reduced the number of available vaporizers, and implemented policies to standardize clinical practice. Using hospital pharmacy purchase order data between 2018 and 2022, GHG emissions and costs from three commonly used volatile anesthetics (Isoflurane, Sevoflurane, and Desflurane) were compared using metric ton carbon dioxide equivalents. Results: During 3 years, GHG emissions from volatile anesthetics were significantly reduced by 77%, with most of the reduction attributed to the reduced use and eventual elimination of Desflurane. Purchase costs were also significantly reduced during this period by 41%. Conclusions: This QI project successfully decreased GHG emissions over 3 years by simultaneously reducing the use of costly and environmentally harmful volatile anesthetic, Desflurane, and increasing the use of low-flow anesthesia. This study addresses our anesthesia practices and healthcare system’s impact on the pediatric population and proposes simple interventions to mitigate the negative consequences of current practices.

Effect of real-time oxygen consumption versus fixed flow-based low flow anesthesia on oxygenation and perfusion: a randomized, single-blind study.

Although low-flow anesthesia is widely used due to its various advantages, there are concerns about potential and relative hypoxia. Furthermore, oxygen is also a drug with benefits and adverse effects. We aimed to evaluate and compare the effect of real-time oxygen consumption versus fixed flow-based low flow anesthesia on oxygenation and perfusion and to compare the economic benefits. With ethical approvals and informed consent, participants were randomly assigned to a dynamic group (13 males, and 27 females) receiving fresh gas flows depending on real-time oxygen consumption (dynamic O2: N2O), and a fixed group (20 males, and 13 females) receiving fixed fresh gas flows of 600 mL/min (with O2: N2O of 1:1). Oxygen partial pressure and serum lactate were comparable between groups. However, isoflurane consumed and costs incurred were significantly different. Total oxygen consumption per minute was also significantly lower in the dynamic group than the fixed group. No episodes of hypoxia were observed in either group. Real-time oxygen consumption-based low flow anesthesia is feasible and cost-effective without affecting the patient's global perfusion and outcome.

Is the reduced risk of post-operative nausea and vomiting in low flow anesthesia applications associated with pre-operative neutrophil/lymphocyte ratio values?

Background/Aim: Post-operative nausea and vomiting (PONV) are defined as nausea and/or vomiting occurring within the first 24 h after surgery and are often observed in the first 2 h after surgery. Only a few previous studies on the use of low fresh gas flow that reduces inhaler agent consumption in laparoscopic cholecystectomy patients at high risk of PONV have been published. Our study aimed to determine the incidence of PONV in the first 30 min and again at 24 h in cases of laparoscopic cholecystectomy in which we applied low fresh gas flow (1 L/min). In addition, we wanted to predict whether the pre-operative neutrophil/lymphocyte ratio (NLR) ≥2 is a risk factor for PONV in our patients to whom we applied low fresh gas flow. Methods: For our prospective cohort study, 80 cases between the ages of 18 and 65, had American Society of Anesthesiologists (ASA) scores of I and II, and who had been scheduled to undergo elective laparoscopic cholecystectomy were included in the study. The NLR limit (calculated by dividing the neutrophil count obtained from the complete blood count before surgery by the lymphocyte count) calculated in the pre-operative period after a patient’s informed consent was obtained was accepted as 2 [5]. Patients were classified into two groups: (1) NLR-I with NLR &lt;2 and (2) NLR-II with NLR ≥2. Premedication was not used in either group. Results: A total of 80 patients were included in the study. They were divided into two groups for classification purposes: (1) NLR-I (n=40) and (2) NLR-II (n=40). The characteristics of the patients in both groups, such as gender distribution, ASA scores, smoking status, mean age, and body mass index (BMI) values, were not different. Sevoflurane consumption in the groups was similar (P=0.169). The time required to complete surgery was longer in the NLR-II group (P=0.025). Nausea/vomiting and antiemetic use were similar in the NLR-I and NLR-II groups in which low fresh gas flow was applied in the first 30 min and 24 h (P=0.500). Although nausea/vomiting was more common in the female and non-smoking group in the first 30 min and 24 h, it was not statistically significantly different from males and smoking groups (P=0.325). However, nausea/vomiting was more common and significantly different in the ASA II versus the ASA I group (P=0.046). The time required to complete surgery was longer, and sevoflurane consumption was higher in patients with nausea and vomiting (P=0.001). Conclusions: Pre-operative NLR as classified by the two groups was not associated with an increase in the risk of PONV in patients to whom we applied low fresh gas flow. A decrease in sevoflurane consumption due to low fresh gas flow may lead to a reduction in the risk of PONV in at-risk patients.

Multimodal approach to perioperative protection in children in abdominal surgery: A prospective comparative study

OBJECTIVE: To increase the effectiveness of perioperative protection by using combined multimodal analgesia (CMA) with epidural blockade (EA) with bupivacaine in combination with low-flow anesthesia with sevoflurane in traumatic abdominal surgery in children.&#x0D; MATERIALS AND METHODS: A prospective comparative study was conducted (n=102, from 1 to 17 years). Surgical planned pathology: Hirschsprung disease, Ledd and Payr syndrome, liver echinococcosis, enterocystoma, pancreatic cyst. Study period: 20182022. Patients were divided into two groups depending on the technique of anesthesia and management of the postoperative period. Group 1 (n=55) received CMA + EA with bupivacaine 0.5%. In the postoperative period prolonged EA with bupivacaine 0.25% 0.51 mg/kg. Comparison group 2 (n=47) traditional general anesthesia based on opioids. For the treatment of postoperative pain syndrome (PPS) promedol 0.3 mg/kg. The effectiveness of perioperative analgesia in pediatric abdominal surgery, the time of development and intensity of postoperative pain syndrome were evaluated.&#x0D; RESULTS: The data obtained as a result of the study clearly showed that the advantages lie behind the optimized method of combined multimodal analgesia CMA + EA with bupivacaine 0.5%. In general, the effectiveness of CMA in combination with epidural analgesia in the intraoperative period was quite high. Additional intraoperative administration of fentanyl was registered in 8 (14.5%) of cases. The stability of hemodynamic parameters and neuroendocrine status was noted in almost all patients of the main group. Analyzing the time of development and intensity of PPS, it can be argued that patients of group 1 had better indicators: the duration of the pain-free period was 2 times longer and the intensity of PPS was lower than in children of group 2. Motor blockade gradually resolved in patients on average, after 20946 minutes. By this time, there was a recovery of the sensation of a pinprick and motor activity in 32 (58.1%) of patients according to the Bromage 2 scale. Analysis of the results of an oral survey of patient satisfaction with pain relief conducted 24 hours after surgery showed that in group 1 the number of cases 43 (78.1%) satisfied with the level of pain relief was 1.5 times higher compared to the control group 24 (51.1%).&#x0D; CONCLUSION: Combined multimodal analgesia in combination with epidural blockade with bupivacaine in traumatic abdominal surgery in children provides sufficient perioperative stability of the hemodynamic and neuroendocrine status, significantly reduces the pharmacological burden, reduces complications, early activation of patients and rapid postoperative rehabilitation compared to the traditional method.

EFEKTIVITAS TEKNIK ANESTESI LOW FLOW DIBANDINGKAN TEKNIK ANESTESI INHALASI STANDAR PADA ANAK USIA 1-6 TAHUN YANG MENJALANI OPERASI DI PROF. DR. I.G.N.G. NGOERAH DENPASAR

Since the discovery of sevoflurane, it has been commonly used due to its many advantages, including its safety profile for pediatric anesthesia practice. However, currently no ideal recommendation for how much gas flow should be used during induction in children. High fresh gas flow (FGF) causes waste of anesthetic and oxygen gases, making it both uneconomical and environmentally polluting. To date, there have been very few studies on low FGF in children, so there is no best and efficient method for reducing the need for large amounts of induction gas. The aim of this study is to determine the effectiveness of the low low anesthesia (LFA) technique in reducing sevoflurane volume, induction time, and hemodynamics during surgery in children undergoing surgery. This is a case-control study conducted at Prof. Dr. I.G.N.G Ngoerah Hospital in Denpasar. Forty-six children aged 1 - 6 years underwent elective surgery and were anesthetized with sevoflurane and randomly divided into two groups: the case group using the low-flow anesthesia technique and the control group using the standard anesthesia technique. The case and control groups were statistically similar in terms of demographic data. However, the volume of sevoflurane used from the time of premedication to intubation was significantly different (p &gt; 0.05) between the two groups (35.5 ml vs 44.5 ml). The induction times were not significantly different (209s vs 201s, p&lt;0.05). Additionally, no significant difference was observed regarding hemodynamic stability during anesthesia.&#x0D; Keywords : anesthesia induction, hemodynamic stability, low flow anesthesia, sevoflurane

Liquid Metal-Based Electrode Array for Neural Signal Recording.

Neural electrodes are core devices for research in neuroscience, neurological diseases, and neural-machine interfacing. They build a bridge between the cerebral nervous system and electronic devices. Most of the neural electrodes in use are based on rigid materials that differ significantly from biological neural tissue in flexibility and tensile properties. In this study, a liquid-metal (LM) -based 20-channel neural electrode array with a platinum metal (Pt) encapsulation material was developed by microfabrication technology. The in vitro experiments demonstrated that the electrode has stable electrical properties and excellent mechanical properties such as flexibility and bending, which allows the electrode to form conformal contact with the skull. The in vivo experiments also recorded electroencephalographic signals using the LM-based electrode from a rat under low-flow or deep anesthesia, including the auditory-evoked potentials triggered by sound stimulation. The auditory-activated cortical area was analyzed using source localization technique. These results indicate that this 20-channel LM-based neural electrode array satisfies the demands of brain signal acquisition and provides high-quality-electroencephalogram (EEG) signals that support source localization analysis.

Low Flow Anesthesia – Mission Impossible?

Because low flow anesthesia reduces waste of environmentally unfriendly inhaled anesthetics, it is coming in the spotlights – again. Despite a detailed theoretical description, considerable teaching efforts of this simple technique have not succeeded in consistently lowering fresh gas flows (FGF) during manual control1. Worse, even though technology has solved the hurdles of manual delivery and the technology is widely available, we fail to maximally implement it. The delivery of inhaled anesthetics with high FGF prior to securing the airway remains common practice. We fail to consistently adjust MAC to age and poorly titrate opioids to reduce the fraction of the MAC we administer. We fail to incorporate hysteresis which is reflected in the use of excessively high FGF and vaporizer settings during wash-in and in the failure to maintain low FGF prior to emergence (“coasting”). By failing to fully appreciate the quantitative effects of the delivery if inhaled anesthetics we miss the opportunity to reduce waste to the absolute minimum. Belief and myth are strong when the environmental impact of inhaled anesthetics is considered. We need better, detailed life cycle analyses with low flow data before making claims pro/con inhaled/TIVA. We tend to lose sight of perspective, and have to continue to weigh the impact of drug selection on patient care.

Low-Flow Anesthesia...100 Years Later

Anesthesia Patient Safety Foundation| March 2023 Low-Flow Anesthesia...100 Years Later Jeffrey M. Feldman, MD, MSE; Jeffrey M. Feldman, MD, MSE Search for other works by this author on: This Site PubMed Google Scholar Samsun (Sem) Lampotang, PhD, FSSH, FAIMBE Samsun (Sem) Lampotang, PhD, FSSH, FAIMBE Search for other works by this author on: This Site PubMed Google Scholar ASA Monitor March 2023, Vol. 87, 36. https://doi.org/10.1097/01.ASM.0000922056.23891.43 Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Facebook Twitter LinkedIn MailTo Cite Icon Cite Get Permissions Search Site Citation Jeffrey M. Feldman, Samsun (Sem) Lampotang; Low-Flow Anesthesia...100 Years Later. ASA Monitor 2023; 87:36 doi: https://doi.org/10.1097/01.ASM.0000922056.23891.43 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAll PublicationsASA Monitor Search Advanced Search Topics: fluid flow “The signs of oxygen want and plane of anesthesia as shown by color, muscular phenomena, etc. must be watched constantly...” Ralph Waters, MD, Anesthesia & Analgesia, 1926 One hundred years ago, Dr. Ralph Waters introduced carbon dioxide absorbents to facilitate rebreathing of exhaled anesthetics, and reduce the need for adding fresh gas and anesthetic to the breathing circuit. Advantages included reduced use (cost) of inhaled anesthetics, reduced exposure of the surgical team to anesthetics, since scavenging systems were not used, and better preservation of the patient's temperature and airway humidity. As the quote above from his 1926 article indicates, Dr. Waters was concerned about the safety implications of reducing fresh gas flow, specifically inadequate oxygen and inadequate anesthetic depth (Anesth Analg 1926;5:160-2). With careful clinical observation, Dr. Waters was able to safely practice low-flow anesthesia using a bag-mask type device with an integrated CO2 absorbent. In... You do not currently have access to this content.

The Effects of Low Flow and Normal Flow Desflurane Anesthesia on Liver and Renal Functions and Serum Cystatin C Levels in Geriatric Patients: A Prospective Randomized Controlled Study

Introduction: Aging is a physiological process and the elderly population is increasing. In parallel to the increasing of the elderly population, the number of geriatric patients who required an invasive procedure or surgical intervention under anesthesia are also increasing. The geriatric patients who are frailty and have a loss of functional reserve in all organ systems are more sensitive to anesthetic agents. The purpose of this research was to investigate whether low flow desflurane anesthesia also affects hepatic and kidney functions, in elderly patients. Methods: After approval from the local ethics committee, the patients were divided into two groups; as the low flow desflurane anesthesia group and the normal flow desflurane anesthesia group using the closed-envelope method. Calibration and leakage tests of the anesthesia device (Primus, Drager) were performed before anesthesia. Heamodynamics parametres, peripheral oxygen saturation, and bispectral index monitoring were performed to all patients in operating room. The blood samples were collected before anesthesia induction, after surgery, and at the postoperative 24th hour. The serum alanine aminotransferase and aspartate aminotransferase levels were measured to assess the liver damage. The serum creatinine, blood urea nitrogen, and cystatin C levels were measured to assess the kidney function. Results: The serum alanine aminotransferase, aspartate aminotransferase, blood urea nitrogen, creatinine and cystatin C levels and hemodynamic parameters, peripheral oxygen saturation and bispectral index values were similar in both groups. Conclusions: It was concluded that low-flow desflurane anesthesia does not adversely affect liver and kidney functions in geriatric patients and is as safe as normal-flow desflurane anesthesia. Keywords: Anesthesia; Cystatin C; Desflurane; Aged; Kidney; Liver.

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.

Comparison of Recovery Profile and Cost-effectiveness of Sevoflurane and Desflurane using Low Flow Anaesthesia in Adults: A Randomised Clinical Study

Introduction: Newer inhalational agents, like sevoflurane and desflurane, offer advantages of rapid induction and early recovery due to their low blood gas solubility. However, cost remains a major drawback of these agents, despite the reduction in agent consumption achieved through low flow anaesthesia. Aim: To evaluate the recovery profile and cost-effectiveness of sevoflurane and desflurane using low flow anaesthesia in adults. Materials and Methods: A randomised clinical study was conducted at, Department of Anaesthesia, Bharati Vidyapeeth Medical College, Pune, Maharashtra, India, during October 2019 to August 2021, with 60 patients classified as American Society of Anaesthesiologists (ASA) I or II, aged 18-65 years, undergoing elective surgeries lasting 1-4 hours under general anaesthesia with the low flow technique. Group S received sevoflurane, while group D received desflurane. Anaesthesia was maintained using a 50/50 mixture of oxygen/air and either sevoflurane or desflurane, depending on the group. The inhalational agents were titrated intraoperatively to achieve a Minimum Alveolar Concentration (MAC) of approximately one. The amount of inhalational agent consumed was calculated, and recovery profiles were studied. The means of continuous variables were compared using an Independent sample t-test, with p-values &lt;0.05 considered significant. Results: In Groups S and D, the mean ages were 39.17 years and 41.5 years, and the percentages of males were 30% and 50%, respectively. The mean times to swallowing, spontaneous eye opening, limb movements, establishing spontaneous regular breathing, responding to verbal commands, extubation, stating a name on command, and achieving a modified Aldrete score ≥9 in minutes were 6.13, 4.87, 5.07, 4.57, 7.40, 8.97, 10.40, and 11.50, respectively. These values were significantly lower in group D. The mean cost per hour and average volume consumption were significantly higher in group D. Conclusion: The study concludes that desflurane provides faster and better recovery from anaesthesia. Although the total cost of desflurane was higher compared to sevoflurane, its use can be beneficial for faster emergence, early transfer from the Post Anaesthesia Care Unit (PACU), and earlier discharge from the hospital.