Does early extubation after cardiac surgery lead to a reduction in intensive care unit length of stay?

Summary A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was whether early extubation (EE) after cardiac surgery leads to a reduction in intensive care unit (ICU) length of stay (LOS)? A total of 564 papers were found using the reported search, of which 4 were randomized trials and hence represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. EE was defined as extubation in theatre (n = 2), within 6 h of surgery (n = 1) and within 8 h of surgery (n = 1). EE was associated with significantly reduced ICU LOS in all studies. Despite the Society of Thoracic Surgeons using extubation <6 h after surgery as a measure of quality, this study has demonstrated that no standardized definition for EE currently exists. The body of evidence identified in this work has demonstrated that for appropriately selected patients (avoiding patients with multiple comorbidities, advanced age and undergoing complex non-elective surgery) early tracheal extubation is associated with a reduction in ICU LOS without an increase in the rate of postoperative complications.


INTRODUCTION
A best evidence topic was constructed according to a structured protocol. This is fully described in the ICVTS [1].

CLINICAL SCENARIO
You are an adult cardiac surgeon who suggests to colleagues that early extubation (EE) of patients would lead to reduced intensive care unit (ICU) length of stay (LOS). Your colleagues are not convinced, and you therefore review the literature to identify any randomized trials performed, which will help inform your discussion.

SEARCH STRATEGY
A literature search was undertaken using PubMed from 01 January 2000 to 31 January 2021 to identify articles for inclusion. The employed search strategy was: [

SEARCH OUTCOME
A total of 564 papers were found using the reported search. All abstracts were screened by 2 reviewers (Marcus Taylor and Denish Apparau) and all potentially relevant studies were subsequently reviewed in full by the same 2 reviewers. Any disagreements regarding article selection were resolved by discussion with an additional reviewer (Nnamdi Nwaejike). All non-randomized and retrospective studies were excluded. We included all comparative randomized trial papers, which provided ICU LOS data for EE versus non-EE adult patients undergoing cardiac surgery. To include only papers relevant to contemporary practice, all studies published prior to 2000 were also excluded. Only studies where the extubation strategy differed between groups were included. After screening all relevant papers, 4 papers were identified that provided the best evidence to answer the question. These are presented in Table 1.

RESULTS
The 4 studies ranged in size from 49-200 patients included. All were single-centre randomized trials. Reported outcome metrics   included mean [± standard deviation (SD)] ICU stay (n = 2) and median [± interquartile range (IQR)] ICU stay (n = 2), with all studies reporting outcomes measured in hours. Amongst the studies, EE was defined in 3 different ways. These included extubation in theatre (n = 2), within 6 h of surgery (n = 1) and within 8 h of surgery (n = 1). Totonchi et al. [2] included 100 patients aged 18-65 with left ventricular ejection fraction >35% and body mass index 18-25 kg/m 2 undergoing elective on-pump coronary artery bypass grafting (CABG), valve surgery or atrial septal defect closure prior to 2018. The 2 groups were well matched in terms of preoperative characteristics. Whilst the EE group had a significantly shorter cross-clamp time, there was no significant difference between groups with regard to cardiopulmonary bypass times. The median ICU stay was significantly reduced for patients extubated in theatre [34 h (± IQR 21.5-44) vs 48 h (± IQR 44-60), P < 0.001]. In total, 96.0% (n = 48) of the patients in the EE group were extubated in theatre. Drainage in the first 24 h was significantly lower for the EE group but was not significantly different between groups for the subsequent 24 h. There were no cases of reintubation. No other complications were detailed in the study.
Salah et al. [3] included 52 patients undergoing all elective cardiac surgery procedures between 2011 and 2013. The mean ICU stay was significantly reduced for patients extubated in theatre [57.4 h (± SD 18.6) vs 95.0 h (± SD 33.6), P < 0.001]. However, the groups were not well matched: patients in the EE group had significantly fewer comorbidities, significantly higher mean left ventricular ejection fraction and significantly shorter cardiopulmonary bypass and cross-clamp times. Only 1 patient in the EE group was not extubated in theatre. Whilst the rate of postoperative bleeding was significantly higher in the EE group, the rate of postoperative myocardial ischaemia was significantly lower. The rates of all other complications, including reintubation, did not differ significantly between groups.
Probst et al. [4] included 200 patients undergoing elective onpump CABG and/or valve surgery or atrial septal defect closure prior to 2014. The 2 groups were well matched in terms of preand intraoperative characteristics. The median ICU stay was significantly shorter for patients extubated within 6 h of surgery [3.3 h (± IQR 2.7-4.0) vs 17.9 h (± IQR 10.3-24.9), P < 0.001]. In total, 97.0% (n = 97) of the patients in the EE group were extubated within 6 h of surgery. The rate of cardiac arrhythmia, prolonged respiratory insufficiency and need for cardiopulmonary resuscitation was significantly lower for the EE group. The rates of all other complications, including reintubation, did not differ significantly between groups. There was also no significant difference in overall hospital LOS between the 2 groups (P = 0.42).
Simeone et al. [5] included 49 patients undergoing elective onpump CABG or valve surgery between February and November 1999. The 2 groups were well matched in terms of pre-and intraoperative characteristics. The mean ICU stay was significantly reduced for patients extubated within 8 h of surgery [29.0 h (±SD 15.8) vs 46.1 h (±SD 33.9), P < 0.001]. The proportion of patients successfully undergoing EE was not reported. In addition, no formal comparison of the rate of complications between groups was presented.

CLINICAL BOTTOM LINE
Despite the Society of Thoracic Surgeons using extubation <6 h after surgery as a measure of quality [6], this study has demonstrated that no standardized definition for EE currently exists. The body of evidence identified in this work has demonstrated that for appropriately selected patients (avoiding patients with multiple comorbidities, advanced age and undergoing complex non-elective surgery) early tracheal extubation is associated with a reduction in ICU LOS without an increase in the rate of postoperative complications.