Hypotension and a positive fluid balance are associated with delirium in patients with shock

Abstract

The pathogenesis of delirium in critically ill patients is multifactorial. How hypotension and hypoxemia affect brain function and whether they can promote delirium remains unclear. A high cumulative positive fluid balance may also have a negative effect on brain function and promote delirium. We hypothesized that delirium would be more likely to develop in patients with low systemic arterial pressure, hypoxemia and a higher positive fluid balance, and investigated these associations in a prospective observational cohort study in patients with shock. After initial resuscitation, episodes of hypotension, defined as a mean arterial pressure (MAP) <65 mmHg or diastolic pressure <60 mmHg, and hypoxemia, defined as peripheral oxygen saturation (SpO2) <90% for more than one minute or any arterial oxygen concentration (PaO2) <90 mmHg, were recorded during the first 5 days of the ICU stay. Fluid balance was evaluated daily and the 5-day cumulative fluid balance recorded. Delirium was assessed using the Confusion Assessment Method for the ICU. A total of 252 patients were admitted with shock during the study period; 185 (73%) developed delirium. Patients who developed delirium also had more episodes of hypotension with a low MAP (p = 0.013) or diastolic pressure (p = 0.018) during the first five days of the ICU stay than those who did not. Patients with a higher cumulative fluid balance during the same period were also more likely to develop delirium (p = 0.01); there was no significant difference in the occurrence of hypoxemia between groups. Joint modeling, combining a linear-mixed model and an adjusted Cox survival model showed that low diastolic pressure (alpha effect = -0.058±0.0013, p = 0.043) and a positive cumulative fluid balance (alpha effect = 0.04±0.003, p = 0.021) were independently associated with delirium. In conclusion, low diastolic pressure and a cumulative positive fluid balance but not hypoxemia were independently associated with development of delirium in patients with shock.

Incidence and predictors of delirium on the intensive care unit after acute myocardial infarction, insight from a retrospective registry

“…Hypotension was also an independent predictor of delirium, which was recently shown in patients with shock and patients with intraoperative hypotension. 27,28 Although hypoxemia was significantly more often observed in patients with delirium, multivariate regression showed hypoxia not to be an independent risk factor of delirium in our analysis. While hypoxia is shown to be associated with postoperative delirium, no association was shown in patients with shock.…”

Impact of a Premorbid Psychiatric Disorder on the Incidence of Delirium during ICU Stay, Morbidity, and Long-Term Mortality

“…In order to minimize the effect of other disease states with overlapping symptoms, such as postanoxic encephalopathy and neurosurgical sequelae, these patients were not included in the study. Finally, it must be acknowledged that it is impossible to take all potential risk factors for the development of delirium in the ICU into account, and specific markers may be generally accounted for in severity of illness indices [32].…”

Incidence and predictors of delirium on the intensive care unit in patients with acute kidney injury, insight from a retrospective registry

“…Most literature on delirium focuses on specific patient cohorts such as mechanically ventilated patients, elderly or surgical patients when investigating delirium 32 , 33 . In these patients, common predictors for delirium are age, shock, alcohol misuse, and mechanical ventilation 1 , 12 , 15 , 34 , 35 . We could confirm these independent predictors of delirium in patients with AKI.…”