[Intrahospital mortality after discharge from the ICU (hidden mortality) in patients who required mechanical...

Our goal was to determine the hidden mortality (HM) in patients who underwent an episode of mechanical ventilation (MV). We also analyzed the factors associated with an increase in the risk of hidden mortality.

Prospective cohort study. Patients admitted to an ICU who required MV and who were monitored until their discharge from hospital. We performed a multivariate study with a logistic regression model including all the variables that were present in a univariate analysis p < 0.20.

Forty-one of the 215 patients who were discharged from the ICU died when they were admitted to hospital, which represents a hidden mortality rate of 19% (CI 95% 11%-27%). A mean period of 9 days elapsed between discharge from the ICU and patient's death, with 25% of patients dying within the first two days. Commonest cause of death was respiratory failure (37%). Factors independently associated with an increase in the risk of hidden mortality were (values expressed as adjusted odds ratio (CI 95%): age > 74 years 1.15 (1.01 to 1.26) (p = 0.02); APACHE II > 29 1.14 (1.01 to 1.27) (p = 0.04); reason for MV being coma 1.21 (1.07 to 1.37) (p = 0.002); reason for MV being cardiopulmonary arrest 1.28 (1.18 to 1.68) (p < 0.001); tracheotomy in ICU 1.31 (1.19 to 1.68) (p < 0.001) and stay in the ICU longer than 16 days 1.35 (1.01 to1.70) (p = 0.04).

An important number of patients discharged from the ICU after an episode of MV die in hospital. Risk factors associated with an increased risk of death in hospital identify a group of patients who, after excluding those with non-cardiopulmonary resuscitation orders, would possibly benefit from high surveillance or intermediate care units.