Study: Rapid response lowers in-hospital arrests

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Implementation of a rapid response system had a significant impact on medical and surgical patients in terms of the occurrence of and survival from a cardiac arrest out of the intensive care unit (ICU). However, researchers could not explain the disproportionate number of arrests in the medical patients, according to a study published in the April issue of Resuscitation.

Rapid response systems (RRS) developed from the recognition that cardiac arrest in hospitalized patients is frequently preceded by unrecognized or unattended signs of physiologic instability.

The researchers noted that despite the success of RRS, little data are available that distinguish between medical and surgical patients.

"Such a differentiation may be relevant because hospitalized medical patients tend to be older and have more co-morbidities than surgical patients. Conversely, surgical patients may have a heightened inflammatory response or risk opiate overdose, particularly in the early post-operative period, and surgeons may be less available to acutely ill patients due to activities in the operating room," they wrote.

Babak Sarani, MD, and colleagues from the Hospital of the University of Pennsylvania undertook this study to determine if these two groups manifest different signs of impending critical illness and therefore require different urgent interventions.

The Hospital of the University of Pennsylvania in Philadelphia implemented an RRS in July 2006. In July 2007, the team was split into a medical and surgical arm. Members of the medical emergency team that are common to both arms include an ICU nurse, pharmacist, respiratory therapist and a member of the patients' primary resident team.

During the day, an ICU attending physician or fellow from the medical or surgical ICU responds to all calls from their respective services. Night and weekend medical emergency team activations are attended by covering residents from the respective services with remote intensivists who are available for consultation by phone if needed.

The surgical medical emergency team responds to all events that occur in patients admitted to the departments of surgery, otorhinolaryngology, orthopedics, neurological surgery and obstetrics and gynecology. The cardiac surgical service is excluded from the RRS. The medical emergency team responds to all other patient groups.

For the study, Sarani and colleagues retrospectively reviewed the incidence of out of ICU cardiac arrests and hospital mortality two years prior to and following RRS implementation.

There were 1,082 RRS activations: 286 surgical and 796 medical. Surgical patients were more likely to have received sedation within 24 hours of evaluation (14 percent vs. 4 percent). The majority of patients in both cohorts were discharged alive.

Researchers found that out of ICU cardiac arrests per 1,000 discharges significantly decreased following RRS implementation (4.07 vs. 2.32), despite no significant change in the case mix index.

Prior to implementation of the RRS, the incidence of cardiac arrest was almost three times higher on the medical service than the surgical service (5.01 vs. 1.69). After implementation of the RRS, both services saw a significant reduction in cardiac arrest, but the degree of reduction was significantly higher in the medical cohort (40 percent reduction) compared with the surgical cohort (32 percent reduction).

After RRS implementation, the medical service continued to have a significantly higher incidence of cardiac arrest than the surgical service (3.02/1,000 discharges vs. 1.16/1,000 discharges). However, hospital mortality decreased significantly on the medical service (25 percent) following implementation of the RRS compared with no significant change in the surgical group, according to the study.

Sarani and colleagues concluded that the potential benefits of having separate RRS for medical and surgical services include "greater physician familiarity with the expected hospital course, the common causes for deterioration and the patient's primary team." Such a strategy could streamline evaluation and expedite appropriate therapy, they said.

Researchers also called for future studies to determine the cause for the disproportionate effects and event rates in the medical service arm.