The Impact of Automatic Lung Recruitment Postoperative Pulmonary Complications

N/ANot Yet RecruitingNCT07477951

Yongtao Sun58 enrolled

Overview

Study Background and Purpose As society ages, an increasing number of elderly patients undergo surgery. Following surgery, particularly abdominal procedures, patients are susceptible to lung-related issues such as atelectasis (lung collapse) and infection, collectively known as Postoperative Pulmonary Complications (PPCs). These complications are a major factor affecting the recovery of elderly patients. One method of general anesthesia is called Total Intravenous Anesthesia (TIVA). This study aims to investigate whether using an automated lung recruitment function, a smart feature available on modern anesthesia machines, can help protect lung function and reduce complications in elderly patients undergoing laparoscopic surgery under TIVA. The goal is to identify safer and more effective methods for anesthesia care. Study Design This is a clinical research study. Eligible elderly patients who provide consent will be randomly assigned to one of two groups: Study Group: The automated lung recruitment function on the anesthesia machine will be used to manage breathing during surgery. Control Group: Current standard methods for breathing management will be used during surgery. The primary goal is to observe and compare the blood oxygenation level 30 minutes after surgery (a key indicator of lung function) between the two groups. The investigators will also record the occurrence of any lung-related complications within the first 3 days after surgery. What Will Participants Do? If participants agree to participate, they will be asked to: Sign an informed consent form. Undergo some pre-operative assessments arranged by the research team. Receive the corresponding breathing management method during surgery, as determined by random assignment. Allow the research team to collect relevant medical data after surgery (e.g., blood gas analysis results, medical records). All data will be kept strictly confidential. Participation does not involve any additional invasive procedures. All medical care and monitoring will adhere to the standard safety protocols required for the surgery, and may even be more meticulous. Potential Benefits and Risks of the Study Potential Benefits: Direct Benefit: Participants will receive more precise monitoring and care for their respiratory function during and after surgery. Societal Value: Data from their participation will contribute to developing better anesthesia strategies for future elderly patients, potentially improving their recovery outcomes. Potential Risks and Protections: The study intervention is integrated into standard anesthesia. The main risks are associated with routine anesthesia and surgery itself (e.g., temporary blood pressure fluctuations, low oxygen levels). These risks are possible in any similar surgical procedure. The study will be conducted by experienced anesthesiologists with continuous, close monitoring. Comprehensive emergency plans are in place to ensure participant safety. Participants have the right to withdraw from the study at any time, for any reason, without affecting their eligibility for any future standard medical care. All personal information and study data will be kept strictly confidential. Data will be analyzed using coded identifiers only. Any published results will not contain information that could reveal the identity of participants.

Interventions

Automated recruitment maneuver (Auto-RM)DEVICE

In addition to total intravenous anesthesia (TIVA) combined with volume-controlled ventilation (VCV), an automated recruitment maneuver was performed using the HuaSheng Lavender intravenous anesthesia machine at 10 minutes after intubation or laryngeal mask insertion and again at 10 minutes before the end of surgery. The maneuver employed the PEEP incremental method as follows: the ventilator was set to pressure-controlled ventilation (PCV) mode with a respiratory rate of 10 breaths/min, an inspiratory-to-expiratory ratio of 1:1, and a controlled pressure maintained at 10-15 cmH₂O. Starting from the baseline PEEP level, PEEP was increased by 5 cmH₂O every 30 seconds until peak pressure reached 40 cmH₂O. Subsequently, PEEP was gradually decreased, and the PEEP level corresponding to the minimum driving pressure (DP = plateau pressure - PEEP) during the recruitment process was recorded and maintained intraoperatively.

Eligibility

Sex: ALLMin age: 65 Years

Medical Language ↔ Plain English

Inclusion Criteria: * aged≥65 years * American Society of Anesthesiologists (ASA) grades I-III; * Body mass index (BMI) between 18-30kg/m² * No history of drug allergy or abnormal anesthesia; * Patients undergoing laparoscopic gastrointestinal surgery, and operative time\> 2 hours; * Participants with a preoperative oxygen saturation not \< 94% * Participants for whom extubation is planned in the operating room. * The assess respiratory risk in surgical patients in Catalonia (ARISCAT) score is 26-44 or \> 44. Exclusion Criteria: * ALI or ARDS patient within 3 months; severe pulmonary dysfunction; severe COPD (FEV1 \<50% of predicted value) or pulmonary hypertension; * New York Heart Association classification: Class IV; * Chronic renal failure(GFR\<30ml min-11.73m-2); * Severe liver disease; * Patients with confusion and cognitive dysfunction; * Severe coagulation disorders; * Patients with tracheal tubes transported to the ICU; * Other reasons;

Outcomes

Primary Outcomes

oxygenation index (PaO₂/FiO₂ ratio) at 30 minutes after extubation

Arterial blood samples were collected for blood gas analysis

Time frame: 30 minutes after extubation

Secondary Outcomes

extubation time, duration of PACU stay after anesthesia

The time interval from the end of surgery to successful tracheal extubation, and the interval from PACU admission to meeting discharge criteria and actual PACU discharge, were recorded. The former was recorded by the anesthesia nurse according to clock time, with timestamps automatically captured by the anesthesia information management system. The latter was documented by the PACU nurse, noting the specific times of admission and discharge.

Time frame: until actual discharge from the PACU

Incidence of postoperative shivering

Postoperative shivering was assessed using the Wrench grading scale (0-4). Grade 0 indicated no shivering; Grade 1 indicated piloerection, peripheral vasoconstriction, or peripheral cyanosis without visible muscle tremor; Grade 2 indicated tremor confined to a single muscle group; Grade 3 indicated tremor involving multiple muscle groups; and Grade 4 indicated generalized gross muscular activity. Shivering was considered clinically significant (event) when the Wrench grade was ≥3. If such shivering persisted for more than 3 minutes, a rescue dose of meperidine was administered.

Time frame: Day 1

The incidence of pulmonary complications occurring within the first 7 days following surgery

The occurrence of postoperative pulmonary complications (PPCs) during hospitalization, including pulmonary infection, acute respiratory failure, pleural effusion, atelectasis, pneumothorax, bronchospasm, aspiration pneumonia, and acute respiratory distress syndrome (ARDS), was assessed by reviewing electronic medical records, imaging systems, and laboratory databases. The incidence of individual postoperative pulmonary complications (PPCs) within 7 days after surgery was recorded, including atelectasis, pneumonia, and acute respiratory distress syndrome (ARDS). Each complication was defined according to standardized criteria (e.g., for pneumonia: new lung infiltrate plus fever \>38°C and leukocytosis). The occurrence of any PPC was considered an adverse outcome.

Time frame: up to 7 days

Incidence of postoperative hypoxemia (SpO₂ < 94%) within 24 hours after surgery

Pulse oximetry monitoring was applied; the number of episodes, duration, and whether any interventions were taken were recorded.

Time frame: Day 1

QoR-15 (15-item Quality of Recovery) scores on postoperative days 1, 2, and 3

QoR-15 scores were assessed on postoperative days 1, 2, and 3 using the 15-item Quality of Recovery (QoR-15) scale，range: 0-150, with higher scores indicating better recovery.

Time frame: Days 1, 2, and 3

all-cause mortality within 30 days after surgery

Survival status was assessed daily during hospitalization. Patients discharged before postoperative day 30 were followed up by telephone on day 30. Deaths were verified through hospital records, death registries, or family reports.

Time frame: up to 30 days

Incidence of postoperative nausea and vomiting (PONV) at 24, 48, and 72 hours after surgery

Nausea and vomiting were graded using the following scale: Grade 1: Mild nausea and abdominal discomfort, but no vomiting; Grade 2: Transient vomiting, ≤1 episode; Grade 3: Vomiting requiring antiemetic therapy, ≤2 episodes; Grade 4: Vomiting refractory to antiemetic therapy, ≥3 episodes.

Time frame: Days 1, 2 and 3

Postoperative NRS scores at 24, 48, and 72 hours

Pain intensity was assessed using the Numeric Rating Scale (NRS), an 11-point scale ranging from 0 (no pain) to 10 (worst imaginable pain), with higher scores indicating more severe pain.