Clinical application of a condenser disposable humidifier (artificial nose) (the forth report)

Abstract

Patients associated with pulmonary hypertension are apt to develop respiratory failure after open heart surgery. Therefore, we performed pulmonary function tests before and after cardiac operation. In addition, during the postoperative period, the alveolar-arterial oxygen tension difference (A-aDo₂) and pulmonary shunt ratio (Qs/Qt) were determined in 36 patients. The patients were divided to three groups, depending on preoperative pulmonary pressures.
The group 1;9 patients with pulmonary hypertension.
The group 2;18 patients without pulmonary hypertension.
The group 3;9 patients with tetralogy of Fallot.
The group 1 showed the lowest value of percent vital capacity, suggesting restrictive lesions. The lowest values of percent maximum minute breathing volume, air velocity index and forced vital capacity suggesting obstructive lesions were shown in the group 1.
Paco₂ were between 28 torr and 35.4 torr in the each group.
Therefore, normal alveolar ventilation were observed in each group.
Pao₂ was lowest in group 1.
However, both A-aDo and Qs/Qt were highest in the group 1. It was suggested that numerous scattered atelectasis or patch atelectasis played the whole or major roles in abnormality of the indices in the group 1. In the group 1, We could often observe atelectasis because of insufflation of dry gas due to non-rebreathing method.
Preventing postoperative respiratory complications due to dried airway, a disposable condenser humidifier (artificial nose) was employed during operation. Animal experiments and clinical results showed that the preservation of respiratory function was attained by using the artificial nose in terms of A-aDo₂ and Qs/Qt. In addition, electromicroscopic studies indicated better preservation of mucociliary epithelium of the bronchus in the group treated with DH.
It was concluded that DH was effective for preservation of respiratory function during and after operation.