Respiratory Changes Induced by Upper Abdominal and Cardiac Surgery. In: Vincent JL, editor. Update 1990. Berlin: Springer Berlin Heidelberg; 1990. pp. 166-73. [DOI: 10.1007/978-3-642-84125-5_17]

Iatrogenic-induced dysfunction of the neuromuscular respiratory system

In the presence of respiratory symptoms that are associated with alveolar hypoventilation or a restrictive ventilatory defect and in the absence of parenchymal or pleural abnormalities on the chest radiograph, iatrogenic causes must be evoked, exactly as they are in the presence of interstitial lung disease. In most cases, the anamnestic and clinical contexts provide a strong diagnostic presumption. It is important to establish carefully the mechanism of the observed disorders, using the currently available arsenal of diagnostic tools for clinical and prognostic reasons and from a medicolegal standpoint. It is necessary to evaluate precisely the clinical repercussions of the respiratory neuromuscular abnormality to serve as a basis for follow-up and to discuss therapeutic options in certain cases (eg, nocturnal ventilation to correct nocturnal hypoventilation due to diaphragmatic dysfunction, diaphragm plication to alleviate dyspnea after complete phrenic nerve destruction, phrenic nerve pacing), again in the perspective of medicolegal actions.

Effect of bi-level positive airway pressure (BiPAP) nasal ventilation on the postoperative pulmonary restrictive syndrome in obese patients undergoing gastroplasty

STUDY OBJECTIVE

Upper abdominal surgery results in a postoperative restrictive pulmonary syndrome. Bi-level positive airway pressure (BiPAP System; Respironics Inc; Murrysville, Pa), which combines pressure support ventilation and positive end-expiratory pressure via a nasal mask, could allow alveolar recruitment during inspiration and prevent expiratory alveolar collapse, and therefore limit the postoperative pulmonary restrictive syndrome. This study investigated the effect of BiPAP on postoperative pulmonary function in obese patients after gastroplasty.

DESIGN

Prospective controlled randomized study.

SETTING

GI surgical ward in a university hospital.

PATIENTS

Thirty-three morbidly obese patients scheduled for gastroplasty were studied.

INTERVENTION

The patients were assigned to one of three techniques of ventilatory support during the first 24 h postoperatively: O2 via a face mask, BiPAP System 8/4, with inspiratory and expiratory positive airway pressure set at 8 and 4 cm H2O, respectively, or BiPAP System 12/4 set at 12 and 4 cm H2O. Pulmonary function (FVC, FEV1, and peak expiratory flow rate [PEFR]) were measured the day before surgery, 24 h after surgery, and on days 2 and 3. Oxygen saturation by pulse oximeter (SpO2) was also recorded during room air breathing.

RESULTS

Three patients were excluded. After surgery, FVC, FEV1, PEFR, and SpO2 significantly decreased in the three groups. On day 1, FVC and FEV1 were significantly improved in the group BiPAP System 12/4, as compared with no BiPAP; SpO2 was also significantly improved. After removal of BiPAP System 12/4, these benefits were maintained, allowing faster recovery of pulmonary function. No significant effects were observed on PEFR. BiPAP System 8/4 had no significant effect on the postoperative pulmonary restrictive syndrome.

CONCLUSION

Prophylactic use of BiPAP System 12/4 during the first 24 h postoperatively significantly reduces pulmonary dysfunction after gastroplasty in obese patients and accelerates reestablishment of preoperative pulmonary function.