Lung and chest wall mechanical properties before and after cardiac surgery with cardiopulmonary bypass

Abstract

From measurements of airway and esophageal pressures and flow, we calculated the elastance and resistance of the total respiratory system (Ers and Rrs), chest wall (Ecw and Rcw), and lungs (EL and RL) in 11 anesthetized-paralyzed patients immediately before cardiac surgery with cardiopulmonary bypass and immediately after chest closure at the end of surgery. Measurements were made during mechanical ventilation in the frequency and tidal volume ranges of normal breathing. Before surgery, frequency and tidal volume dependences of the elastances and resistances were similar to those previously measured in awake seated subjects (Am. Rev. Respir. Dis. 145: 110-113, 1992). After surgery, Ers and Rrs increased as a result of increases in EL and RL (P < 0.05), whereas Ecw and Rcw did not change (P > 0.05). EL and RL exhibited nonlinearities (i.e., decreases with increasing tidal volume) that were not seen before surgery, and RL showed a greater dependence on frequency than before surgery. The changes in RL or EL after surgery were not correlated with the duration of surgery or cardiopulmonary bypass time (P > 0.05). We conclude that 1) frequency and tidal volume dependences of respiratory system properties are not affected by anesthesia, paralysis, and the supine posture, 2) open-chest surgery with cardiopulmonary bypass does not affect the mechanical properties of the chest, and 3) cardiac surgery involving cardiopulmonary bypass causes changes in the mechanical behavior of the lung that are generally consistent with those caused by pulmonary edema induced by oleic acid (J. Appl. Physiol. 73: 1040-1046, 1992) and decreases in lung volume.

Isoflurane pre-treatment before cardiopulmonary bypass alleviates neutrophil accumulation in dog lungs

“…Postulated causes include atelectasis, pulmonary oedema, inflammation, increased capillary permeability, and pleural effusions 25. Dogs pre-treated with isoflurane in our experiment showed significantly reduced DLC values after CPB, as did the control group.…”

Massive Pulmonary Eden During Extracorporeal Circulation

“…Fizyolojik şantlar ve alveolo-arteriyel oksijen farkı artmaktadır. Sonuç olarak; kompliyansta azalma, atelektazilerde artma, solunum iş yükünde artma, şantlarda artma ve interstisyal ödemin ortaya çıkardığı postoperatif pulmoner disfonksiyon tablosu gelişebilmektedir [4][5][6] . Uzun süre ve fazla miktarda sigara içme öyküsü ve buna bağlı amfizem tablosu postoperatif pulmoner disfonksiyon gelişimini etkileyen en önemli risk faktörleridir.…”

The effects of heart surgery on early and late pulmonary functions: the results of three-year follow-up

“…Anestezi, ameliyat sırası olaylar, mekanik değişiklikler, diyafram disfonksiyonu, uygulanan medikasyon, hastaların ameliyat sonrası hemodinamik durumları önemli faktörlerdir. [8][9][10][11] Ameliyat sonrası ağrı pulmoner fonksiyonlarda bozulmaya katkıda bulunur ve sternotomi ağrısı ameliyattan sonra da yıllarca devam edebilir. [5] Koroner arter bypass greftleme ameliyatından sonra oluşan AKG değişiklikleri; dolaşım yetmezliğine, akciğer hastalığına veya mekanik ventilasyon değişiklik-lerine bağlı olabilir.…”