Anesthesia, Surgery--Complications
Conditions
Keywords
Mechanical ventilation
Brief summary
Background. The use of a comprehensive strategy providing low tidal volumes, peep and recruiting maneuvers in patients undergoing open abdominal surgery improves postoperative respiratory function and clinical outcome. It is unknown whether such ventilatory approach may be feasible and/or beneficial in patients undergoing laparoscopy, as pneumoperitoneum and Trendelenburg position may alter lung volumes and chest-wall elastance. Objective. The investigators designed a randomized, controlled trial to assess the effect of a lung-protective ventilation strategy on postoperative oxygenation in obese patients undergoing laparoscopic surgery.
Interventions
Anaesthesia induction will be obtained with i.v. 2-3 mg/kg propofol, 0,6-0,8 mcg/kg fentanyl, and 0.9-1,2 mg/kg rocuronium. Anaesthesia will be maintained with i.v. propofol continuous infusion, with a dose titrated to achieve a bi-spectral index value between 40 and 50
Balanced crystalloids will be administered to patients in both groups as a standard rate of 3-5 ml/kg/h. Treatment of eventual hemodynamic instability will be left to the attending physician
DIAGNOSTIC_TESTEsophageal pressure measurement
A nasogastric polyfunctional tube (Nutrivent, Sidam, Italy) will be placed after anaesthesia induction in all enrolled patients to measure esophageal pressure, estimate pleural pressure and compute transpulmonary pressure
DIAGNOSTIC_TESTLung volume measurement with the nitrogen washin-washout technique
Lung volume will be measured through nitrogen wash-in wash-out technique and low-flow Pressure-volume curve will be recorded to estimate differences in alveolar recruitment between the two study groups.
Sponsors
Catholic University of the Sacred Heart
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
NONE
Eligibility
Sex/Gender
FEMALE
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* scheduled for gynaecological laparoscopic surgery in the Trendelenburg position * Obesity with body mass index\>35 kg/m\^2 * written informed consent
Exclusion criteria
* Clinical history or signs of chronic heart failure * history of neuromuscular disease * history of thoracic surgery * pregnancy * chronic respiratory failure requiring long-term oxygen administration
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Postoperative oxygenation | One hour after extubation | PaO2/FiO2 ratio 1 hour after extubation, while the patient is receiving oxygen through VenturiMask 40% |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Postoperative forced vital capacity (FVC) | 48 hours after the end of surgery | the total amount of air exhaled during a forced expiratory maneuver started from the level of total lung capacity |
| Postoperative Tiffeneau index | 48 hours after the end of surgery | computed as FEV1/FVC |
| Postoperative Dyspnea | 1 hour after surgery | Dyspnea assessed by Borg dyspnea scale |
| Pulmonary infection | 24 hours after the end of surgery | modified clinical pulmonary infection score (mCPIS) |
| Postoperative pulmonary infiltrates | 24 hours after the end of surgery | Evaluated with the chest x-ray by two independent clinicians blinded to treatment assignment |
| Intraoperative driving pressure | during surgery, recorded on a 60-minute basis | driving pressure, computed as Plateau pressure-PEEP |
| Postoperative forced expiratory volume in 1 second (FEV1) | 48 hours after the end of surgery | volume exhaled during the first second of a forced expiratory maneuver started from the level of total lung capacity |
| Intraoperative oxygenation | during surgery, recorded on a 60-minute basis | PaO2/FiO2 |
| Intraoperative dead space | during surgery, recorded on a 60-minute basis | Approximated as the difference between End-tidal CO2 and PaCO2 divided by PaCO2 |
| Lung recruitment | during surgery, recorded on a 60-minute basis | lung recruitment/changes in end expiratory lung volume between the two groups |
| Intraoperative blood pressure | during surgery, recorded on a 60-minute basis | Arterial blood pressure |
| Intraoperative respiratory system compliance | during surgery, recorded on a 60-minute basis | computed as Tidal volume/airway driving pressure |
| Intraoperative lung compliance | during surgery, recorded on a 60-minute basis | computed as Tidal volume/lung driving pressure |
| Intraoperative lung driving pressure | during surgery, recorded on a 60-minute basis | transpulmonary driving pressure, computed as Transpulmonary end-inspiratory pressure-transpulmonary total end-expiratory pressure |
Countries
Italy
Outcome results
None listed