Blood pressure, oxygen saturation predict death in terminally ill

Sep 12 2012

By Sarah Guy, medwireNews Reporter

The most reliable events that predict impending death in terminally ill cancer patients being treated palliatively are decreased blood pressure and low oxygen saturation, show study results.

The researchers report that a combination of these two signs predicted death within 48 hours with a 95.0% positive predictive value and a 81.4% negative predictive value.

The most common symptom among the 181 patients who died between August 2009 and December 2011 was confusion, experienced by a third (n=60) of the cohort. However, confusion only had a 33.3% positive predictive value, indicating a poor ability to accurately predict death.

"Although it is never certain what may happen when a sudden change develops, the results of the current study could assist care planning and family discussions," suggest In-Cheol Hwang (Gachon University Gil Hospital, Incheon, South Korea) and colleagues.

The study participants were a median 67 years old, had medical records available for the last 7 days of life, and were most commonly diagnosed with gastrointestinal cancer.

After adjustment for potential confounding factors including age, gender, primary cancer site, and cancer treatment, a decrease in blood pressure (drop of 20 mmHg for systolic or 10 mmHg for diastolic from the former stable value), which was experienced by 90.1% of the cohort, was significantly associated with death after 48 hours, with an odds ratio for survival of 0.96.

Confusion, increased pulse rate (>20% average), low oxygen saturation (<90% using pulse oximetry), death rattle (respiratory sounds associated with movement of secretions), and consciousness level (responsive to voice, pain, or nonresponsive) were all also significantly associated with imminent death, with respective ORs of 0.97, 0.97, 0.96, 0.96, and 0.94.

Hwang and co-workers used these associations in a logistic regression analysis and found that the most significant and accurate predictor for death within the following 48 hours was the combination of decreased blood pressure and low oxygen saturation.

"Survival prediction in terminal cancer patients remains important both for patients and for their families, especially when they are confronted with end-of-life issues, like deciding about further burdensome treatment options," remark the researchers in Supportive Care in Cancer.

Their results may improve the accuracy of such a prognosis, which palliative care doctors are known to find difficult, they conclude.

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