Effects of Low-Flow and Standard-Flow Sevoflurane Anesthesia on Inflammatory Markers in Bariatric Surgery (LOWBAR)

Adana City Training and Research Hospital

Status: Completed

Conditions: Inflammation; Bariatric Surgery Candidate; Obesity

Study type: Observational

Funder types: Other

Identifiers

NCT07230704

ADN-LOWFLOW-2025

10-354 (Other Identifier)

Details and patient eligibility

About

This retrospective observational study aimed to compare the effects of low-flow and standard-flow sevoflurane anesthesia on perioperative inflammatory responses in patients undergoing laparoscopic sleeve gastrectomy for obesity. Data were obtained from the anesthesia and laboratory records of 155 adult patients who received either low-flow (1 L/min) or standard-flow (4 L/min) sevoflurane anesthesia between January 2022 and January 2025 at Adana City Training and Research Hospital. Preoperative and postoperative inflammatory markers, including C-reactive protein (CRP), neutrophil-to-lymphocyte ratio (NLR), and red cell distribution width (RDW), were recorded and compared between the two groups. Hemodynamic parameters such as mean arterial pressure and heart rate were also analyzed to assess intraoperative stability. The primary objective of the study was to evaluate the impact of anesthetic flow rate on perioperative inflammation, while the secondary objective was to assess hemodynamic stability during anesthesia. This study may contribute to a better understanding of how low-flow anesthesia influences systemic inflammatory responses and perioperative hemodynamics in morbidly obese patients undergoing bariatric surgery.

Full description

This retrospective observational cohort study investigated the effects of low-flow and standard-flow sevoflurane anesthesia on perioperative inflammatory markers and hemodynamic stability in patients with obesity undergoing laparoscopic sleeve gastrectomy. The study included 155 adult patients operated between January 2022 and January 2025 at Adana City Training and Research Hospital, Adana, Turkey.

Patients were divided into two groups according to the fresh-gas flow rate used during anesthesia:

Low-flow group: sevoflurane with a total fresh-gas flow rate of 1 L/min,

Standard-flow group: sevoflurane with a total fresh-gas flow rate of 4 L/min.

All patients received general anesthesia as part of routine clinical care. No randomization or intervention was performed by the investigators. Demographic characteristics, anesthesia records, intraoperative hemodynamic parameters (mean arterial pressure, heart rate), and perioperative laboratory results were obtained retrospectively from hospital electronic records.

Preoperative and postoperative (24-hour) values of inflammatory markers-including C-reactive protein (CRP), neutrophil-to-lymphocyte ratio (NLR), and red cell distribution width (RDW)-were compared within and between groups. The primary endpoint was the change in these inflammatory biomarkers between pre- and postoperative measurements. The secondary endpoint was the comparison of intraoperative hemodynamic stability (MAP and HR variability, incidence of hypotension or bradycardia) between the two groups.

This study aims to provide evidence regarding whether low-flow sevoflurane anesthesia (1 L/min) offers comparable or superior inflammatory and hemodynamic profiles compared with standard-flow anesthesia (4 L/min) in morbidly obese patients. The findings may help optimize anesthetic techniques for bariatric surgery by balancing patient safety, hemodynamic stability, and environmental considerations.

Enrollment: 155 patients

Sex: All

Ages: 18 to 60 years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• Adult patients aged 18-60 years
• Underwent laparoscopic sleeve gastrectomy under general anesthesia
• Received low-flow or standard-flow sevoflurane anesthesia
• ASA physical status I-III
• Complete perioperative records available

Exclusion criteria

• Conversion to open surgery
• Incomplete or missing data
• Significant comorbidities (e.g., severe cardiac, hepatic, or renal dysfunction)
• Perioperative complications unrelated to anesthesia
• Age <18 or >60 years

Trial design

155 participants in 2 patient groups

Low-flow Sevoflurane

Description:

Patients who underwent laparoscopic sleeve gastrectomy under general anesthesia with low-flow sevoflurane (fresh gas flow = 1 L/min). Data were obtained retrospectively from hospital records.

Standard-flow Sevoflurane

Description:

Patients who underwent laparoscopic sleeve gastrectomy under general anesthesia with standard-flow sevoflurane (fresh gas flow = 4 L/min). Data were obtained retrospectively from hospital records.