Risk Factors for Prolonged Mechanical Ventilation Following Surgery for Acute Type A Aortic Dissection

Abstract

ompared to the relatively favorable in-hospital outcomes of acute type B aortic dissection, 1,2 acute type A aortic dissection (AAAD) remains one of the most serious cardiovascular diseases associated with a high mortality. The latest report from the International Registry of Acute Aortic Dissection Investigators group indicated that in-hospital mortality remains high (163 of 682 patients (23.9%) with AAAD treated surgically between 1996 and 2003). 3 With such critical illness, some patients require prolonged mechanical ventilation (PMV) after surgery. Compared with patients who undergo other cardiac surgeries, patients with AAAD are more likely to suffer preoperative hemodynamic instability, organ malperfusion, and prolonged cardiopulmonary bypass (CPB) during surgery. In addition, re-exploration for bleeding and neurological deficits are common postoperative complications in these patients. 4 All these factors can contribute to PMV after AAAD surgery. 5 Another factor related to the PMV is systemic inflammatory response-related lung injury evoked by acute aortic dissection. 6,7 A number of studies regarding PMV following cardiac surgery have examined its predictors or its influence on clinical outcomes and costs. [8][9][10][11][12][13][14][15][16][17] However, little is known about PMV following AAAD surgery. The aim of this retrospective study was to identify predictors of PMV following AAAD surgery and to assess the influence of PMV on the short and long-term postoperative courses. MethodsFrom January 1997 through to December 2006, 243 consecutive patients with AAAD underwent emergency surgery at our hospital. Aortic dissection was diagnosed by means of enhanced computed tomography scan or echocardiography, and transesopageal echocardiography was used for confirmation when possible. In all patients, emergency surgery was performed within 14 days after the onset of symptoms; 90% of these surgeries were performed within 48 h. So that we could focus on PMV, 10 patients who died within 48 h after surgery were excluded from the study. Death within 48 h after surgery was due to profound cardiac failure (8 patients) or refractory bleeding (2 patients). The remaining 233 patients (120 men, 113 women, mean age: 63.4±11.2 years) were divided into 2 groups according to the duration of mechanical ventilation: those who were tracheally extubated within 48 h after admission to the intensive care unit (ICU) (group A, n=149) and those who required mechanical ventilation for more than 48 h (group B, n=84). Patients who were reintubated within 24 h after extubation were considered to have an interrupted period of ventilation. To identify the independent predictors for PMV, we compared 48 perioperative factors (25 preoperative factors and 23 intra or postoperative factors) between the 2 groups. Mortality and morbidity, length of the ICU and hospital stays, and long-term survival were compared

Risk factors for postoperative hypoxemia in patients undergoing Stanford A aortic dissection surgery

“…In our study, the long-term survival in non-hypoxemia group was better than that in hypoxemia group, which was in accordance with previous studies [13]. Survivors following cardiac surgery are found to enjoy a good quality of life after discharge.…”

Prolonged ventilation post cardiac surgery - tips and pitfalls of the prediction game

“…It may be classified as postoperative ventilation continued for more than 12 hours [14], 24 hours [15,16], 48 hours [17], 72 hours [18], or even 96 hours after the operation [19]. Not surprisingly then, the results obtained may be contradictory and of very limited practical applicability.…”

“…What is more, authors tend to narrow down the groups of subjects, creating predictive models for prolonged ventilation in patients after one type of procedure only - for example, after coronary revascularisation with cardiopulmonary bypass [14,15], adult valve procedures [16,20],or aortic aneurysm surgery [17]. The only benefit of this approach is the increased homogeneity of the studied group.…”

Effects of inhaled nitric oxide for postoperative hypoxemia in acute type A aortic dissection: a retrospective observational study

“…Hypoxemia prolongs postoperative mechanical ventilation and intensive care unit (ICU) stay and increases postoperative mortality. However, effective medical interventions are limited and controversial [6][7][8].…”