Documenting Rapid Response System afferent limb failure and associated patient outcomes

ObjectiveDescribe afferent limb failure (ALF), defined as documented Rapid Response System (RRS) calling criteria, but no associated call, in the 24 h prior to an event.MethodsRetrospective medical record and database review. Adult in-patients whose hospital length of stay (LOS) was greater than 24 h, an event being a cardiac arrest, Medical Emergency Team (MET) call or unanticipated Intensive Care Unit (ICU) admission.ResultsOver 6 months, there were 443 patients with 575 events, of which 35 (6.1%) were cardiac arrests, 395 (68.7%) MET calls, and 145 (25.2%) ICU admissions. 131 (22.8%) events had documented ALF, of which 47/131 (35.9%) had documented criteria across more than one time period. Patients with ALF, compared to those without ALF, were significantly more likely to have an unanticipated ICU admission (45/131 (34.4%) vs 100/443 (22.5%), p = 0.01), but be of similar age (71 years vs 72 years, p = 0.44), male gender (51.1% vs 53.2%, p = 0.38), APACHE 2 score (22.8 vs 21.4, p = 0.67), predicted risk of death (0.394 vs 0.367, p = 0.55), ICU LOS (2 days vs 2 days, p = 0.56), likelihood of not-for-resuscitation order during an event (4/131 (3.4%) vs 22/444 (5.0%), p = 0.34), and hospital mortality (42/107 (39.3%) vs 125/236 (37.2%), p = 0.70). Hospital mortality for patients with ALF across multiple, compared to single time periods was higher, 21/40 (52.5%) vs 22/69 (31.9%), p = 0.03.ConclusionsRRS ALF is a useful performance measure for a mature RRS, and is associated with unanticipated ICU admissions. The duration of, and not timing of, ALF criterion occurrence may affect hospital mortality.