Use of positive pressure in the bariatric surgery and effects on pulmonary function and prevalence of atelectasis: randomized and blinded clinical trial

Abstract

BackgroundIn surgical procedures, obesity is a risk factor for the onset of intra and postoperative respiratory complications.AimDetermine what moment of application of positive pressure brings better benefits on lung function, incidence of atelectasis and diaphragmatic excursion, in the preoperative, intraoperative or immediate postoperative period.MethodRandomized, controlled, blinded study, conducted in a hospital and included subjects with BMI between 40 and 55 kg/m2, 25 and 55 years, underwent bariatric surgery by laparotomy. They were underwent preoperative and postoperative evaluations. They were allocated into four different groups: 1) Gpre: treated with positive pressure in the BiPAP mode (Bi-Level Positive Airway Pressure) before surgery for one hour; 2) Gpos: BIPAP after surgery for one hour; 3) Gintra: PEEP (Positive End Expiratory Pressure) at 10 cmH2O during the surgery; 4) Gcontrol: only conventional respiratory physiotherapy. The evaluation consisted of anthropometric data, pulmonary function tests and chest radiography.ResultsWere allocated 40 patients, 10 in each group. There were significant differences for the expiratory reserve volume and percentage of the predicted expiratory reserve volume, in which the groups that received treatment showed a smaller loss in expiratory reserve volume from the preoperative to postoperative stages. The postoperative radiographic analysis showed a 25% prevalence of atelectasis for Gcontrol, 11.1% for Gintra, 10% for Gpre, and 0% for Gpos. There was no significant difference in diaphragmatic mobility amongst the groups.ConclusionThe optimal time of application of positive pressure is in the immediate postoperative period, immediately after extubation, because it reduces the incidence of atelectasis and there is reduction of loss of expiratory reserve volume.

Bilevel positive airway pressure in two moments after bariatric surgery

“…In this study, the fact that the ERV did not change compared to preoperative values in the PAR-G shortly after extubation and that the 1PO-G had lower values demonstrates the need to reexpand collapsed alveolar units as early as possible. A study by Baltieri et al 16 comparing the use of positive pressure in the preoperative, intraoperative, and immediate postoperative phases demonstrated that it is always beneficial in restoring the ERV; however, when applied in the immediate postoperative, it decreases the prevalence of atelectasis.…”

“…Therefore, the present research group has been studying effective ways to restore lung volumes and capacities and prevent atelectasis in the post-operative period following bariatric surgery. A preliminary study by Baltieri et al 16 demonstrated beneficial effects of the application of bilevel positive airway pressure (BiPAP) on the restoration of expiratory reserve volume (ERV) and reduction in atelectasis immediately after extubation, while still in the post-anesthetic recovery (PAR) room. The objective of the present study was to compare the effects of BiPAP application on the immediate postoperative period, while still in the post-anesthetic recovery room, during the first postoperative day, concerning pulmonary function and the prevalence of atelectasis.…”

The physiotherapy management of patients undergoing abdominal surgery

“…Since the 2006 publication of these systematic reviews (Lawrence et al 2006, Pasquina et al 2006, seven additional RCTs have been published (Baltieri et al 2014, Barbalho-Moulim et al 2011, Dronkers 2008, Kulkarni et al 2010, Samnani et al 2014, Zhang et al 2015. The findings of these further studies are summarised in Table 3 and the results and context of the findings are discussed elsewhere in this paper where appropriate.…”

Non-Invasive Preventive Ventilation With Two Pressure Levels in the Postoperative Period of Roux-en-Y Gastric Bypass: Randomized Trial

“…The use of non-invasive ventilation (NIV) is currently method capable of offering positive pressure, which is useful in increasing oxygenation, reducing respiratory complications, and increasing the incidence of anastomosis dehiscences 1 . NIV can be offered in the two-level (bilevel) or positive airway (CPAP) mode and is an alternative for the prevention of pulmonary complications, as it decreases muscle fatigue, improves functional residual capacity (FRC), reduces areas of intrapulmonary shunt through the recruitment of collapsed alveolar units, aiming at the adequate maintenance of gas exchange, facilitating alveolar ventilation and reducing dyspnea, reducing respiratory work 1 , 2 .…”