A recent Mayo Clinic study (Weingarten 2012) identified risk factors for activation of emergency response teams (ERT) for patients discharged from PACUís (post-op anesthesia care units) to regular nursing units. The overall rate of such ERT activation in the first 48 hours was 2 in 1000 cases and 62% of these occurred within the first 12 hours. They found that 3 factors predicted such ERT activation: (1) preoperative central nervous system comorbidity (2) preoperative opioid use and (3) intraoperative use of phenylephrine infusion or increased intraoperative fluid administration (used as proxies for intraoperative hemodynamic instability). Hypotension, changes in mental status, and respiratory problems were the leading reasons for ERT activation. Patients needing ERT activation had longer lengths of stay and more severe in-hospital complications, including higher 30-day mortality rates. They suggest that patients with these risk factors might be considered for discharge to higher levels of care (ICUís or step-down units).
Of the 30% of ERT patients who used opioids, 13% received naloxone as an ERT intervention. They have a good discussion about other studies showing patients receiving opioids (via PCA or other routes) have higher rates of ERT activation for respiratory depression and that opioid-tolerant patients are particularly problematic.
Note that most of their patients discharged from the PACU to the floor were on supplemental oxygen (61% for their ERT patients and 50% for their controls). Weíve discussed on numerous occasions that supplemental oxygen therapy may mask respiratory depression and delay its recognition if there is only pulse oximetry monitoring and no concomitant capnographic monitoring. Note that it is an extremely common anesthesia practice to use supplemental oxygen post-op. We strongly recommend that before beginning PCA or other IV opioids the patient should be carefully assessed for legitimate indication for supplemental oxygen. If that need is indeed present special monitoring for respiratory depression should be added (monitoring CO2 and monitoring for respiratory rate and apnea).
By the way, the article also has a good discussion on published outcomes of ERTís on surgical patients vs. medical patients. Long-standing debates over the success (or lack thereof) of ERTís (also known as rapid response teams or RRTís) usually focus on whole hospital populations. This article notes that studies of ERTís in surgical populations tend to have more favorable outcomes and that there may be more reversible causes of deterioration in the surgical population that are amenable to ERT interventions.
Weingarten TN, Venus SJ, Whalen FX, et al. Postoperative Emergency Response Team Activation at a Large Tertiary Medical Center. Mayo Clinic Proc 2012; 87(1): 41-49, January 2012