Extracorporeal Venovenous Membrane Oxygenation in the Treatment of Respiratory Insufficiency Following Cardiac Surgery

Unusual severe hypoxemia due to unilateral pulmonary edema after conventional cardiopulmonary bypass salvaged by veno-venous extracorporeal membrane oxygenation: a case report

BACKGROUND

We report a case in which veno-venous extracorporeal membrane oxygenation (V-V ECMO) saved the life of a patient who developed severe hypoxemia due to unusual unilateral pulmonary edema (UPE) after cardiopulmonary bypass (CPB).

CASE PRESENTATION

A 69-year-old man underwent aortic valve replacement and coronary artery bypass grafting. Following uneventful weaning off CPB, he developed severe hypoxemia. The ratio of arterial oxygen tension to inspired oxygen fraction (PaO2/FiO2) decreased from 301 mmHg 5 min after CPB to 42 mmHg 90 min after CPB. A chest X-ray revealed right-sided UPE. Immediately established V-V ECMO increased PaO2/FiO2 to 170 mmHg. Re-expansion pulmonary edema (REPE) was likely, as the right lung remained collapsed during CPB following the accidental opening of the right chest cavity during graft harvesting.

CONCLUSIONS

V-V ECMO was effective in improving oxygenation and saving the life of a patient who had fallen into unilateral REPE unusually developing after conventional CPB.

Management of fulminating non-cardiogenic pulmonary edema following cardiac surgery

A malignant form of non-cardiogenic pulmonary edema (NCPE) that develops soon after the termination of cardiopulmonary bypass support during cardiac surgery is rarely encountered. It sometimes requires immediate management, including venovenous extracorporeal membrane oxygenation (VV-ECMO). In the first case, a 78-year-old female patient experienced fulminating NCPE after mitral valve plasty, which caused severe respiratory failure and hemodynamic instability due to a huge amount of sputum. In the second case, a 47-year-old male patient presented with right-sided unilateral pulmonary edema with a substantial amount of sputum after minimally invasive cardiac surgery for mitral valve repair. In both cases, VV-ECMO and aggressive fluid replacement were promptly initiated. The NCPE resolved on post-operative day 2, resulting in the successful termination of VV-ECMO. NCPE leads to lethal respiratory failure with multifactorial causes during cardiac surgery. However, as NCPE is potentially transient, immediate treatment comprising VV-ECMO and aggressive fluid replacement can improve clinical outcomes.

Prone Positioning in Cardiac Surgery: For Many, But Not for Everyone

Prone positioning is a therapeutic maneuver to improve arterial oxygenation in patients with acute lung injury that is not implemented in most centers performing adult cardiac surgery. The aim of this study was to review our experience with prone positioning to assess the effects of this maneuver in patients with postoperative acute respiratory failure. From 2010-2014, 127 adult patients with postoperative acute respiratory failure were treated with prone positioning in addition to specific therapy. Univariate and multivariate logistic regression analyses were performed to identify independent risk factors associated with in-hospital mortality. In-hospital mortality was 22.8% (n = 29). No significant differences were observed in preoperative risk factors between patients who survived (S) and those who died (D), except for age (62.7 ± 11.2 vs 70.2 ± 11.3; P = 0.007-at multivariate analysis P = 0.03, odds ratio [OR] = 1.1/year). Preproning values of PaO₂/FiO₂ were significantly different between groups (D vs S: 115 ± 46 vs 150 ± 56; P = 0.006), but only preproning FiO₂ remained highly significant at multivariate analysis (D vs S: 0.82 ± 0.18 vs 0.67 ± 0.16; P = 0.001, OR = 1.07; with FiO₂ > 0.75 vs < 75, OR = 19.6). D showed a higher improvement of PaO₂/FiO₂ immediately after prone positioning (207 ± 100 vs 219 ± 90, P = 0.56; within-group analysis between preproning and 1 hour after proning: S-P = 0.49, D-P = 0.019; at 12 hours: 286 ± 123 vs 240 ± 120, P = 0.06; within-group analysis between 1 hour and 12 hours after proning: S-P = 0.15; D-P = 0.17; between groups-P = 0.05). D had higher peak WBC count (26 ± 9.8 vs 17.7 ± 5.9×10³/mL; P = 0.0001) and a higher rate of low output syndrome (15 vs 9 patients-51.7% vs 9.2%; P = 0.0001). At multivariate analysis, white blood cell count: P = 0.005, OR = 1.11/10³ white blood cell; low output syndrome: P = 0.0002, OR = 20.5. In conclusion, our results show that prone positioning, if performed early, is a safe and effective adjunct measure for patients with postoperative acute hypoxemic respiratory failure of noncardiogenic origin.