Pulmonary Atelectasis
Conditions
Keywords
Protective lung ventilation, Laparoscopic surgery, Alveolar recruitment, Pneumoperitoneum, Cholecystectomy, Perioperative respiratory complications, Lung ultrasound score, Lung ultrasound, LUS
Brief summary
This single-centre, prospective, randomized, parallel-group controlled trial evaluated whether alveolar recruitment manoeuvres (RMs) added to a lung-protective ventilation strategy improve perioperative lung aeration in adults undergoing elective laparoscopic cholecystectomy under general anaesthesia. Eighty patients (ASA I-III) were allocated 1:1 to an RM group or a control group. Both groups received identical low-tidal-volume ventilation with 5 cmH₂O PEEP; the RM group additionally received a standardized stepwise recruitment manoeuvre at two points-after establishment of pneumoperitoneum and again before extubation-with PEEP returned to 5 cmH₂O after each manoeuvre. Lung aeration was assessed by an 8-zone lung ultrasound (LUS) protocol at five predefined perioperative time points. The primary outcome was the perioperative composite LUS score trajectory. Peripheral oxygen saturation, mean arterial pressure, and heart rate were assessed as safety outcomes.
Detailed description
Laparoscopic cholecystectomy under general anaesthesia with CO₂ pneumoperitoneum predictably reduces lung aeration and promotes atelectasis that global monitoring parameters may fail to detect. This trial compared two intraoperative ventilation strategies differing solely in the application of alveolar recruitment manoeuvres, using serial lung ultrasound to quantify regional aeration. Adults aged 18-75 years, ASA physical status I-III, scheduled for elective laparoscopic cholecystectomy were eligible. Patients undergoing emergency surgery, with severe pre-existing pulmonary disease (e.g., COPD GOLD stage ≥ III, interstitial lung disease) or previous thoracic surgery, who were pregnant, or who required conversion to open surgery were excluded. Eligible participants were randomized 1:1 using a computer-generated sequence, with allocation concealed by sequentially numbered, sealed, opaque envelopes. All patients received standardized general anaesthesia and volume-controlled ventilation (tidal volume 6-8 mL/kg predicted body weight, PEEP 5 cmH₂O, FiO₂ titrated to SpO₂ ≥ 95%, EtCO₂ 35-40 mmHg). In the RM group, a standardized stepwise recruitment manoeuvre (driving pressure 15 cmH₂O; PEEP incremented 5 → 10 → 15 cmH₂O in 10-15-second steps) was performed twice: first immediately after establishment of CO₂ pneumoperitoneum and surgical positioning, and second after pneumoperitoneum deflation and before extubation. PEEP was returned to 5 cmH₂O after each manoeuvre, identical to the control group, so that the groups differed only by the recruitment manoeuvres and not by sustained PEEP. The control group received no recruitment manoeuvre, with PEEP maintained at 5 cmH₂O throughout. Intra-abdominal pressure was limited to 12 mmHg. An 8-zone LUS protocol (each hemithorax divided into anterior-upper, anterior-lower, lateral-upper, and lateral-lower regions) was applied at five predefined time points: T1, preoperative baseline; T2, 5 minutes after induction; T3, after pneumoperitoneum establishment and the first recruitment manoeuvre; T4, immediately after extubation and the second recruitment manoeuvre; and T5, 30 minutes after arrival in the post-anaesthesia care unit. LUS examinations were performed by a dedicated team of blinded anaesthesiology specialists independent of intraoperative ventilation management. The primary outcome was the perioperative composite LUS score trajectory across the five time points, analysed with a linear mixed-effects model (group, time, and group × time interaction). Safety outcomes were peripheral oxygen saturation, mean arterial pressure, and heart rate at each time point.
Interventions
A standardized stepwise alveolar recruitment manoeuvre applied at two intraoperative time points: after establishment of CO₂ pneumoperitoneum and again before extubation. Each manoeuvre uses a fixed driving pressure of 15 cmH₂O with PEEP incremented stepwise (5 → 10 → 15 cmH₂O, 10-15 seconds per step), then PEEP returned to 5 cmH₂O. The manoeuvre is terminated if peak inspiratory pressure exceeds 35 cmH₂O or haemodynamic instability occurs. Applied in addition to low-tidal-volume protective ventilation.
Volume-controlled low-tidal-volume ventilation (6-8 mL/kg predicted body weight) with 5 cmH₂O PEEP and FiO₂ titrated to maintain SpO₂ ≥ 95%, applied to both groups. Perioperative lung aeration is assessed using a standardized 8-zone lung ultrasound protocol at five predefined time points (preoperative baseline, 5 minutes post-induction, post-pneumoperitoneum, immediately post-extubation, and 30 minutes after PACU arrival) by blinded assessors independent of ventilation management.
Sponsors
Study design
Intervention model description
Two-arm parallel-group randomized controlled trial. Eligible patients were allocated 1:1 to a recruitment manoeuvre group or a control group using a computer-generated randomization sequence with allocation concealment by sequentially numbered, sealed, opaque envelopes. Both groups received identical low-tidal-volume ventilation with 5 cmH₂O PEEP; the groups differed only by the application of standardized alveolar recruitment manoeuvres in the intervention group.
Eligibility
Inclusion criteria
* Adult patients scheduled for elective laparoscopic cholecystectomy under general anesthesia * Age between 18 and 75 years * Body mass index (BMI) \< 30 kg/m² * American Society of Anesthesiologists (ASA) physical status classification I-III * Provision of written informed consent
Exclusion criteria
* Refusal to participate in the study * Emergency surgical procedures * Body mass index (BMI) ≥ 30 kg/m² * American Society of Anesthesiologists (ASA) physical status classification IV
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change in Lung Ultrasound Score (LUS) | Baseline (T0), 30 minutes after pneumoperitoneum (T1), and 30 minutes after desufflation (T2) | Lung ultrasound score (LUS) assessed using a 8-zone scanning technique. Each zone is scored from 0 (normal aeration, A-lines) to 3 (lung consolidation). Total score ranges from 0 to 36, with higher scores indicating worse lung aeration. Change calculated as difference from baseline (T0) to T1 and T2. |
Countries
Turkey (Türkiye)
Contacts
ISTANBUL PROVINCIAL HEALTH DIRECTORATE FATIH SULTAN MEHMET TRAINING AND RESEARCH HOSPITAL
ISTANBUL PROVINCIAL HEALTH DIRECTORATE FATIH SULTAN MEHMET TRAINING AND RESEARCH HOSPITAL
ISTANBUL PROVINCIAL HEALTH DIRECTORATE FATIH SULTAN MEHMET TRAINING AND RESEARCH HOSPITAL
ISTANBUL PROVINCIAL HEALTH DIRECTORATE FATIH SULTAN MEHMET TRAINING AND RESEARCH HOSPITAL
ISTANBUL PROVINCIAL HEALTH DIRECTORATE FATIH SULTAN MEHMET TRAINING AND RESEARCH HOSPITAL
ISTANBUL PROVINCIAL HEALTH DIRECTORATE FATIH SULTAN MEHMET TRAINING AND RESEARCH HOSPITAL
Participant flow
Recruitment details
Participants were prospectively recruited from adult patients scheduled for elective laparoscopic cholecystectomy at a tertiary care hospital according to predefined inclusion and exclusion criteria.
Pre-assignment details
All participants who met the eligibility criteria were enrolled and assigned to the study groups. No participants were excluded prior to assignment.
Baseline characteristics
| Characteristic | — |
|---|---|
| Age, Continuous | 46.05 years STANDARD_DEVIATION 13.65 |
| Body Mass Index (BMI) | 28.2 kg/m² STANDARD_DEVIATION 4.3 |
| Race and Ethnicity Not Collected | 0 Participants |
| Sex: Female, Male Female | 50 Participants |
| Sex: Female, Male Male | 14 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | 0 / 40 | 0 / 40 |
| other Total, other adverse events | 3 / 40 | 12 / 40 |
| serious Total, serious adverse events | 0 / 40 | 0 / 40 |