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ABSTRACT & COMMENTARY
By Richard H. Kallet, MS, RRT, FAARC, FCCM
Director of Quality Assurance, Respiratory Care Services, San Francisco General Hospital
Mr. Kallet reports no financial relationships relevant to this field of study.
SYNOPSIS: Reintubation following unplanned extubation in critically ill post-operative patients is associated with increased hospital mortality.
SOURCE: Lee JH,et al. Clinical outcomes after unplanned extubation in a surgical intensive care population. World J Surg 2014;38:203-210.
This retrospective study of more than 4000 immediate postoperative patients requiring mechanical ventilation (MV) examined whether unplanned extubation (UE) is associated with increased hospital mortality. Nursing staff ratios were either 1:1 or 1:2. Reintubation was assessed in the first 72 hours following UE. The incidence of UE was 1.8% with 96% patient-initiated. The reintubation rate was 21% compared to 3.4% following planned extubation in the control group. Reintubatation following UE was associated with a higher incidence of ventilator-associated pneumonia (VAP), and a 7-fold higher mortality rate (21%) compared to either UE patients or control patients not requiring reintubation (3%). In the multivariate analysis, in the absence of reintubation UE was not associated with mortality. Hospital mortality also was significantly associated with emergent surgery, chronic neurological disease, and those with an acute physiology and chronic health evaluation (APACHE II) score > 22. The authors speculated that reintubation following UE enhances the mortality risk of comorbidities and other risk factors.
The results of this study, the first exclusively focused on postoperative surgical patients, are consistent with the literature. The most salient and reproducible observation from UE studies is that a sizable proportion of clinically stable patients undergoing UE do not require reinstitution of MV. This strongly suggests that clinicians are too conservative in assessing their patients’ ability to resume unassisted breathing without an artificial airway.
A recent systematic review found that UE occurs more frequently during the weaning phase, in patients who have a higher level of consciousness, and particularly in those exhibiting restlessness and/or agitation.1 Complicating the problem of UE is its association with benzodiazepines (particularly midazolam) as well as with the use of physical restraints. The paradoxical excitatory effects of benzodiazepines and their association with delirium are likely explanations. Nonetheless, clinicians are presented with a nettlesome problem because a near-normal sensorium is a prerequisite for extubation. But both the incidence of restlessness/agitation and its primary treatment increase the risk of UE. However, a recent observational study found that strategies involving either no sedation (i.e., analgesia only) or intermittent sedation were associated with increased UE compared to protocolized continuous sedation with daily sedation interruptions.2 This suggests that the sedation strategy might be the more relevant factor.
The issue of whether using restraints increases the risk of UE is circuitous. Patients generally are restrained because they try to remove catheters. In fact, one prospective study found that lack of hand restraints tripled the incidence of UE.1 Although not a universal finding, nursing staff ratios often are cited as a factor in UE, and up to 90% of UEs occur when a nurse is not at the bedside.1 UE tends to occur more during the night shift and with less experienced nurses.1
The current study is consistent with the literature in that reintubation following UE is associated with higher hospital mortality, as well as with an increased incidence of VAP, prolonged need for MV, and higher hospital costs. These negative consequences are likely attributable to the tendency for UE to occur in older patients (> 65), those with a higher APACHE II scores (> 17), those requiring full-support modes vs weaning modes of ventilatory support (median of 76% vs 15.6%), and those with oxygenation problems.1
The incidence of UE is 3-14% and is now considered a quality-of-care issue.1,3 This may become problematic because, like other signifiers of health care quality (e.g., VAP), UE is a complex problem. There are few high-quality studies and none of them suggest an unambiguous solution. Also, the negative impact of UE is most salient in high-acuity patients. Clearly, a more aggressive approach to extubation in patients who pass a spontaneous breathing trial is needed. Perhaps less obvious, because it runs counter to the current trend toward minimizing sedation, is to emphasize effective treatment of agitation in the critical phase of acute illness (particularly if it is pain-induced). The consequences of UE are most profound in this circumstance. In addition, more mindful peer support from experienced nurses and respiratory therapists toward bedside practitioners new to critical care would likely be helpful in reducing UE.