Thirty-day mortality in critical care outreach patients with cancer: an investigative study of predictive factors related to outreach referral episodes.

Abstract

To establish factors that predict outcome in critically ill, deteriorating cancer patients through critical care outreach referral episodes, characteristics and care reviews. A population-based prospective and retrospective study was undertaken with analysis exploring predictive factors regarding critically ill cancer patients referred to a critical care outreach team. Data collected included: diagnosis; presenting problem; early warning scores at referral and at deterioration; physiological and observation data; admission to critical care, length of stay; 30-day mortality; limitation of care including precipitating DNAR orders and documentation of not for CCU admission/intervention). Data were collected on 407 episodes from 318 patients over a period of 8 months from 2006 to 2007. Outreach initiated decisions to limit care with medical teams in 32.2% (n=103/318) of all patients. Early warning scores were not predictive of outcome. A high heart rate at referral (HR), a high potassium, low SpO2 at time of deterioration were independently predictive of 30-day mortality. The logistic regression (LR) model, using these three variables correctly predicts the 30-day outcome of 71% of the patients, demonstrating a relatively high predictability in this patient population. The odds of mortality increase with a higher potassium, heart rate and as the oxygen saturation at deterioration (DSpO(2)) worsen. Management factors included limitation of care, which is highly associated with 30-day mortality. Cancer patients recently receiving chemotherapy may have an increased mortality once admitted to critical care. Being a haemato-oncology patient, or the timeliness of critical care outreach referral does not appear to affect 30-day mortality. The LR model was able to predict 30-day outcome of 71% of the patients, demonstrating a reasonably high predictability in this cancer patient population. Critical care outreach initiated discussions on limiting treatment which had an effect on mortality.