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Literature Review

Early Extubation: A Proposed New Metric

Crawford TC, Magruder JT, Grimm JC, et al. Semin Thorac Cardiovasc Surg. In press. doi:

Reviewers: Jacob Gutsche, MD1; Ronak Shah, MD1

  1. Hospital of the University of Pennsylvania, Philadelphia, PA

The Society of Thoracic Surgeons (STS) uses a benchmark of 6 hours for early extubation, and failure to extubate a patient undergoing coronary artery bypass grafting (CABG), aortic valve replacement (AVR), or AVR/CABG is a minor morbidity in the STS database reports. Intubation greater than 24 hours is deemed a major morbidity and used to calculate the Star metric for programs reporting to the STS. It is unclear if a cutoff of 6 hours of intubation postcardiac surgery yields an increased risk of mortality or morbidity.


The authors retrospectively queried the Johns Hopkins Cardiac Surgery STS database for patients undergoing AVR, mitral valve replacement (MVR), CABG, AVR/CABG, or MVR/CABG and compared outcomes of patients based on extubation in 1 of 4 time ranges: 0-6, 6-9, 9-12, and 12-18 hours. The outcomes of interest were mortality or one of the major morbidities for cardiac surgery: stroke, renal failure, unplanned reoperation, deep sternal wound infection, and prolonged intubation. Secondary outcomes were prolonged hospital length of stay and reintubation.

Results and Conclusion

Patients with a longer duration of mechanical ventilation had higher STS-predicted risk of morbidity and mortality. There was a lower mortality in patients extubated in less than 12 hours. Diabetes mellitus, pre-existing lung disease, urgent operative status, longer cardiopulmonary bypass duration, and use of intra-aortic balloon pump independently increased the risk of operative mortality. The risk of operative mortality or composite major complication were not different between patients extubated 0-6 vs 6-9 hours, but patients extubated 12-18 hours incurred a higher risk of operative mortality or major postoperative complication. Based on the results, the authors suggest that the 6- and 24-hour standards for extubation be modified to 12 hours.


The Johns Hopkins critical care group aggressively extubates patients in the postoperative period. The STS standards are intended to benchmark hospitals to grade quality and potentially motivate hospitals to change protocols and practice patterns to meet the standard of care. It is clear that prolonged extubation is associated with higher morbidity and mortality, but it also is clear that readiness for extubation is patient-specific and is based on pre-existing conditions such as lung disease or acquired conditions such as stroke. Each institution should use the reported metrics to compare compliance with existing protocols or need to modify them to improve performance.