The use of positive end-expiratory pressure (PEEP) and recruitment maneuvers during laparotomy will limit the development of atelectasis and therefore improve the aeration score.
Postoperative pulmonary complications contribute to the morbidity of surgical patients. During general anesthesia, up to 90% of patients will develop atelectasis, which is thought to be a major contributing factor to their development. The adjustment of ventilator settings to prevent the occurrence of atelectasis and reduce pulmonary complications remains controversial. Despite the use of similar mechanical ventilation strategies, two recent studies (IMPROVE, PROVHILO) involving 1300 patients diverged in their conclusions regarding the impact of these strategies in the prevention of pulmonary complications. In these studies, the absence of imagery to assess the pulmonary end-result of the different ventilation strategies complicates the interpretation of their results. On arrival in the operating theatre, each patient will undergo a baseline lung ultrasound examination. The anesthetic technique and monitoring will be standardized. The radial artery will be cannulated after induction of anesthesia for blood gas monitoring. Ventilator settings will be adjusted according to randomization. A second lung ultrasound examination will be performed 5 minutes following induction of general anesthesia. In the PEEP group, a lung ultrasound examination will be performed immediately following the first recruitment maneuver. A lung ultrasound examination will also be performed at the end of surgery before emergence of general anesthesia. Fifteen minutes after arrival in the recovery room, a last lung ultrasound examination will be performed. Fraction of inspired oxygen (FiO2) and vital signs will be recorded during each ultrasound examination. Arterial blood samples will be collected simultaneously. The aeration score will be calculated for each lung ultrasound examination.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
SINGLE
Enrollment
44
Centre Hospitalier de l'Université de Montréal (CHUM)
Montreal, Quebec, Canada
Lung aeration
Compare lung aeration between two different mechanical ventilation strategies (with or without PEEP and recruitment maneuvers) using ultrasound imaging and a four point aeration score (0 = normal lung, 1 = moderate aeration loss, 2 = severe aeration loss, 3 = complete aeration loss and consolidation).
Time frame: Post-induction to pre-emergence of anesthesia - Day 0
Re-aeration following recruitment maneuvers
Assess lung re-aeration following a recruitment maneuver by ultrasound imaging (lung aeration score pre/post the first recruitment maneuver during general anesthesia).
Time frame: Prior and after the first recruitment maneuver during general anesthesia - Day 0
Atelectasis secondary to induction
Estimate development of atelectasis secondary to intubation.
Time frame: Lung aeration score prior and after intubation - Day 0
Atelectasis secondary to extubation
Estimate development of atelectasis secondary to extubation.
Time frame: Lung aeration score prior and after extubation - Day 0
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