Atelectasis, Nasal Septal Deviation
Conditions
Keywords
Fresh gas flow rate, Low-flow anesthesia, Inhalational anesthesia, Lung ultrasound score, Lung ultrasound, Perioperative atelectasis, Pulmonary aeration, Septoplasty, Desflurane, Post-anesthesia care unit
Brief summary
This prospective, single-center observational cohort study evaluated the association between fresh gas flow rate during inhalational anesthesia and perioperative changes in lung aeration in adults undergoing elective surgery for nasal septal deviation. Participants were classified into two cohorts according to the fresh gas flow rate used during routine anesthesia care: 1 L/min or 3 L/min. The flow rate was selected independently by the attending anesthesiologist as part of routine clinical practice and was not assigned by the research protocol. Lung aeration was assessed using the modified lung ultrasound score before anesthesia, after tracheal intubation, before extubation, 15 minutes after admission to the post-anesthesia care unit, and before discharge from the post-anesthesia care unit. Perioperative oxygenation, hemodynamic variables, respiratory mechanics, and early postoperative recovery findings were also recorded.
Detailed description
This was a prospective, single-center observational cohort study conducted at Fatih Sultan Mehmet Training and Research Hospital. Adult patients aged 18 to 65 years with American Society of Anesthesiologists physical status I or II who underwent elective surgery for nasal septal deviation under general anesthesia were evaluated. All participants provided written informed consent before enrollment. Anesthetic management was performed according to routine institutional clinical practice. The fresh gas flow rate was determined independently by the attending anesthesiologist and was not assigned or modified by the research protocol. Participants were subsequently classified into two observational cohorts according to the documented fresh gas flow rate used during inhalational anesthesia: 1 L/min or 3 L/min. No randomization was performed. Lung ultrasound examinations were performed at five perioperative time points: before induction of anesthesia, after tracheal intubation, before extubation, 15 minutes after admission to the post-anesthesia care unit, and approximately 30 minutes after admission or immediately before discharge from the post-anesthesia care unit. Lung aeration was evaluated in 12 thoracic regions using a modified lung ultrasound score. Each region was scored from 0 to 3 according to the observed ultrasound pattern. A score of 0 represented normal aeration, while scores of 1, 2, and 3 represented mild, moderate, and severe loss of aeration, respectively. The total score ranged from 0 to 36, with higher scores indicating greater loss of lung aeration. The primary objective was to compare perioperative changes in the lung ultrasound score between patients receiving fresh gas flow rates of 1 L/min and 3 L/min during routine anesthesia. Additional recorded variables included heart rate, systolic, diastolic, and mean arterial pressure, peripheral oxygen saturation, perfusion index, end-tidal carbon dioxide, inspired and expired oxygen concentrations, body temperature, peak airway pressure, airway resistance, and dynamic lung compliance. Early postoperative findings, including pain intensity, nausea, vomiting, and shivering, were also evaluated in the post-anesthesia care unit.
Interventions
OTHERFresh Gas Flow Rate of 1 L/min
During routine inhalational general anesthesia, a fresh gas flow rate of 1 L/min was used. The flow rate was selected independently by the attending anesthesiologist according to routine clinical practice and was not assigned or modified by the research protocol. This exposure was evaluated in relation to perioperative changes in the modified lung ultrasound score.
OTHERFresh Gas Flow Rate of 3 L/min
During routine inhalational general anesthesia, a fresh gas flow rate of 3 L/min was used. The flow rate was selected independently by the attending anesthesiologist according to routine clinical practice and was not assigned or modified by the research protocol. This exposure was evaluated in relation to perioperative changes in the modified lung ultrasound score.
Sponsors
Fatih Sultan Mehmet Training and Research Hospital
Study design
Observational model
COHORT
Time perspective
PROSPECTIVE
Eligibility
Sex/Gender
ALL
Age
18 Years to 65 Years
Healthy volunteers
No
Inclusion criteria
* Adults aged 18 to 65 years * Scheduled to undergo elective septoplasty for nasal septal deviation under general anesthesia * American Society of Anesthesiologists physical status I or II * Body mass index of 35 kg/m² or less * Provided written informed consent to participate
Exclusion criteria
* Acute respiratory tract infection within the preceding 15 days * Chronic pulmonary disease * Malignancy * Significant hepatic, renal, or cardiac disease * Limited ability to cooperate with the study assessments * Cerebrovascular or neuromuscular disease * Previous thoracic surgery * Chest wall deformity * Emergency surgery * History of clinically relevant allergy
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Perioperative Change in Modified Lung Ultrasound Score | Preoperative baseline; after tracheal intubation; before extubation; 15 minutes after PACU admission; and approximately 30 minutes after PACU admission or before PACU discharge | Lung aeration was assessed in 12 thoracic regions, six regions in each hemithorax. Each region was scored from 0 to 3: 0 indicated normal aeration, 1 mild loss of aeration, 2 moderate loss of aeration, and 3 severe loss of aeration or consolidation. Regional scores were summed to obtain a total modified lung ultrasound score ranging from 0 to 36. Higher scores indicated greater loss of lung aeration. Changes in the total score across the perioperative time points were compared between the 1 L/min and 3 L/min fresh gas flow cohorts. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Perioperative Peripheral Oxygen Saturation | Preoperative baseline; after tracheal intubation; before extubation; 15 minutes after PACU admission; and approximately 30 minutes after PACU admission or before PACU discharge | Peripheral oxygen saturation (SpO2), expressed as a percentage, was measured using pulse oximetry. Values recorded at the prespecified perioperative time points were compared between the 1 L/min and 3 L/min fresh gas flow cohorts. |
| Intraoperative Dynamic Lung Compliance | Approximately 5 minutes after tracheal intubation and immediately before extubation | Dynamic lung compliance was obtained from the anesthesia machine and recorded in mL/cmH2O. Higher values indicated greater respiratory system compliance. Values were compared between the two fresh gas flow cohorts. |
| Intraoperative Peak Airway Pressure | Approximately 5 minutes after tracheal intubation and immediately before extubation | Peak airway pressure was obtained from the anesthesia machine and recorded in cmH2O during mechanical ventilation. Values were compared between the 1 L/min and 3 L/min fresh gas flow cohorts. |
| Intraoperative Airway Resistance | Approximately 5 minutes after tracheal intubation and immediately before extubation | Airway resistance was obtained from the anesthesia machine during mechanical ventilation and compared between the 1 L/min and 3 L/min fresh gas flow cohorts. |
| Postoperative Pain Intensity | At 15 minutes and approximately 30 minutes after admission to the PACU | Postoperative pain intensity was assessed using a visual analog scale ranging from 0 to 10, where 0 indicated no pain and 10 indicated the worst imaginable pain. |
| Incidence of Nausea, Vomiting, and Shivering in the PACU | From admission to the PACU until PACU discharge, approximately 30 minutes | The occurrence of postoperative nausea, vomiting, and shivering was recorded as present or absent for each participant during recovery in the post-anesthesia care unit. Each event was evaluated separately as the number and percentage of participants experiencing the event. |
Countries
Turkey (Türkiye)
Outcome results
None listed