A new systematic review and meta-analysis (Chan et al 2010) of studies on rapid response teams (RRT’s) again concludes that the evidence fails to support a significant impact of RRT’s on mortality. For adults there was some evidence of a reduction in non-ICU cardiopulmonary arrests (a more modest reduction was seen when only high quality studies were included). However, the meta-analysis showed no overall effect on hospital mortality. In pediatric populations, there was a lower hospital mortality rate seen after implementation of RRT’s. The authors attribute the apparent better outcomes in pediatric populations to the fact that respiratory problems are more frequently the cause of arrest in children and that children overall have far fewer co-morbidities.
The accompanying editorial (Edelson 2010) echoes a point we have made in several of our articles on RRT’s: the weak link is in the recognition of deterioration. Dr. Edelson notes that 2 parameters which have been shown to be predictive of mortality (respiratory rate and mental status) are notoriously poorly monitored. Dr. Edelson also points out that many or our alert systems are based on absolute levels of a vital sign and may miss trends. We actually gave some examples of that in our December 29, 2009 Patient Safety Tip of the Week “Recognizing Deteriorating Patients”.
The need for better systems to identify signs suggestive of deterioration, without creating too many false alarms, is obvious. Along these lines, a new article in Anesthesiology (Taenzer et al 2010) discusses preliminary outcomes for a new system of monitoring post-op orthopedic patients with continuous pulse oximetry at Dartmouth. They developed a system in which data from continuous pulse oximetry was analyzed by computer and tied to a system of notifying the patient’s nurse by pager. Key concepts were setting thresholds that met a balance between high sensitivity and numbers of false alarms. They also incorporated a delay into the notification system to further minimize the number of false alarms that nurses would have to respond to. The ultimate triggers used were an oxygen saturation of less than 80% and a heart rate below 50 or greater than 140. Their preliminary results show a reduction in rescue events and fewer transfers to the ICU. There were also fewer deaths, though the numbers were too small to be considered significant. This is an exciting concept and suggests that noninvasive monitoring tied to computer algorithms might someday operate in the background to help identify patients in need of early intervention.
All this negative evidence does not negate the logic of having a culture of safety that helps recognize early patients that are in need of “rescue”. But it does raise many questions about committing many resources to develop RRT’s without better evidence-based validation of the RRT concept. The idea remains a sound one but the most appropriate targets, the triggers, the makeup of teams, the mode of response, the logistics, and the best outcome measures all need to be validated before hospitals rush willy-nilly into developing RRT’s.
Our other columns on rapid response teams and recognition of clinical deterioration:
Chan PS, Jain R, Nallmothu BK, Berg RA, Sasson C. Rapid Response Teams: A Systematic Review and Meta-analysis. Arch Intern Med. 2010; 170(1): 18-26
Edelson DP. A Weak Link in the Rapid Response System.
Arch Intern Med. 2010; 170(1): 12-13
Taenzer AH, Pyke JB, McGrath SP, Blike GT. Impact of Pulse Oximetry Surveillance on Rescue Events and Intensive Care Unit Transfers: A Before-and-After Concurrence Study. Anesthesiology 2010; 112(2): 282-287