Hypoxemia and hypocarbia following intermittent positive-pressure breathing

Intermittent positive pressure breathing in the cardiac surgery setting: A review

Purpose:

To review the role of intermittent positive pressure breathing in the cardiac surgery setting.

Methods:

This review was conducted by searching seven major databases. A search string was built using the key words ‘intermittent positive pressure breathing’, and ‘cardiac surgery’ matched with the Boolean operator AND. Filters were selected for the publication dates January 2006 to January 2016. In each database, the search was conducted in the fields of the article title, abstract and keywords.

Results:

In total, seven citations that fulfilled the inclusion criteria were included in the final review. There was consensus among the authors regarding the inspiratory pressure values at which intermittent positive pressure breathing should be administered (15–30 cm H2O). The duration of treatment ranged between 15–30 minutes divided into one to three daily sessions, or was carried out considering the number of respirations. With regard to the treatment of pulmonary atelectasis, intermittent positive pressure breathing was shown to be effective after coronary artery bypass grafting, and it was the most cited postoperative intervention used to treat either pulmonary atelectasis and oxygen impairment, in cardiac surgery patients.

Conclusions:

The findings of this review seem to confirm that intermittent positive pressure breathing is still currently being used postoperatively in the cardiac surgery setting to treat surgery-related pulmonary complications.

Effects of breathing therapy with a dead-space-resistance device on post-cardiac surgical patients

The effects of a dead-space-resistance device (IDSEP breather) on Pao2, Paco2 and functional residual capacity (FRC) in 11 post-cardiac surgical patients were studied. There were no significant changes in Pao2, Paco2 and FRC after the IDSEP therapy. Changes in Pao2 between the pre- and post-IDSEP therapy correlated well with changes in FRC (r = 0.797, P less than 0.01). Breathing therapy with the dead-space-resistance device appeared not to bring any benefit in early post-cardiac surgical patients.

Incentive spirometry: its value after cardiac surgery

Treatment with intermittent positive pressure breathing (IPPB) and incentive spirometry (I.S.) was compared in 109 patients after heart surgery with cardiopulmonary bypass. Assessment was done by measurement of vital capacity, arterial oxygen tension and identification of the radiological signs of atelectasis. All patients were instructed pre-operatively in the treatment which was to be used. Vital capacity, arterial oxygen tension while breathing air for the first three postoperative days and the incidence of atelectasis showed no significant difference between groups. Ten minutes after treatment the arterial oxygen tension fell, but this was only statistically significant after I.P.P.B. At 60 minutes the arterial oxygen tension had returned to pretreatment level in both groups. The use of the incentive spirometer four times daily is no better than I.P.P.B., in preventing atelectasis after open-heart surgery. Possibly incentive spirometer treatment given more frequently may be more effective.