Two thirds of patients were comatose (GCS score ≤ 8) at ICU admission, nearly 80% required mechanical ventilation while in the ICU, three quarters had hemorrhagic stroke, and only one quarter received acute-phase stroke therapy. Hospital mortality was 61% and less than one-fifth of patients had a good 6-month neurological outcome. The likelihood of survival with a good neurological outcome was lower in older patients and in those with severe consciousness impairment at ICU admission. Neither the type of stroke nor the use of acute-phase stroke therapy was associated with the 6-month neurological outcome.
The epidemiology of stroke requiring ICU admission is unclear. Most studies were conducted in specific stroke subtypes (subarachnoid hemorrhage or acute ischemic stroke),[8,21] in patients treated with mechanical ventilation,[12,22] or in dedicated stroke units. It has been estimated that 10–20% patients with acute stroke require ICU admission.[8–10] In a German study, mean age of 347 patients admitted to the ICU for acute stroke was 70.8 years, 28.8% of patients were comatose, and 66.6% required intubation. Similarly, in two recent French studies, median age was 63.8–68.2 years, most patients were comatose, and 87 to 100% were intubated.[12,16] Our findings are consistent with these data.
Over the past two decades, outcomes of stroke have been improved by major therapeutic advances such as reperfusion therapy and decompressive craniectomy.[4–6] In the German study cited above, 38.5% of patients with ischemic stroke underwent reperfusion therapy, and in one of the two French studies one-third of patients received reperfusion therapy before ICU admission. In the other French study, conducted over a 10-year period in multiple centers, the proportion of patients given acute-phase stroke therapy increased from 2.9% in 1996–2002 to 21% in 2010–2016. Our results are in line with these data.
Hospital mortality of critically ill patients with stroke has ranged from 16.3 to 70%[8,20,24–30] depending on time period, case mix, ICU admission policies, stroke subtypes, and availability of stroke units. The factors most commonly associated with hospital mortality were older age, use of mechanical ventilation, neurological failure severity at ICU admission, and treatment-limitation policies.[8,13,14] Our study reports a high hospital mortality. However, it should be underlined that patients with subarachnoid hemorrhage were excluded from our study and that the majority of our patients had severe neurological failure at admission and were treated with mechanical ventilation. Finally, these figures are similar to those reported by De Montmollin et al.. In one study, treatment-limitation decisions were made three times more often for patients with stroke than for those with other conditions. The proportion in our study was in accordance with earlier reports,[32–34] and when we confined our analysis to patients without treatment limitations the proportion with an mRS of 0–2 at 6 months increased only moderately, from 20 to 30%.
In addition to survival, functional outcomes are important to consider.[35,36] In a British study in 134 patients, only 13.7% had an mRS of 0–2 after 1 year. Of 111 critically-ill patients, less than 30% had an mRS of 0–3 on day 90. In contrast, of 132 patients admitted for stroke to 16 Spanish ICUs, 43.3% had minimal or no disability at 1 year. However, this study included patients with subarachnoid hemorrhage, and neurological outcomes were good in only 25.0 and 37.1% of patients with ischemic stroke and intracerebral hemorrhage, respectively. In our study, the number of patients mRS 0–2 increased from 23 to 61 between day 28 and month 6, showing some recovery potential with time and underlying the difficulty comparing results at different time points.
Older age and worse consciousness impairment at ICU admission were independently associated with disability and death in our study. Only three earlier studies investigated predictors of functional outcome of ICU stroke patients in the era of reperfusion therapy. In one, a lower GCS score and greater neurological-failure severity independently predicted worse outcomes. In another, the predictors were a lower GCS score, greater acute-illness severity (APACHE II score), and mass effect by computed tomography. Finally, in the remaining study, older age was strongly associated with the neurological outcome after rehabilitation.
Our findings indicate that patients admitted to the ICU for stroke are rarely eligible for acute-phase stroke treatments. Data on the effectiveness of these treatments in ICU patients should not be extrapolated from studies in patients who are not critically ill. The independent associations of age and GCS score at ICU admission with the functional outcomes may help physicians inform patients and families and distinguish between patients eligible for continued full-code care and patients for whom transitioning to end-of-life care is more appropriate.
A major strength of our study is the larger sample size compared to earlier similar studies. Moreover, the ICU management of acute stroke remained unchanged during the 5-year recruitment period. Data on the primary outcome were missing for only 3% of patients. The mRS used to assess the primary outcome has been extensively validated and has demonstrated low interobserver and intraobserver variability. Finally, we identified predictors of the 6-month functional outcome. One limitation of our study is the single-center recruitment, which may restrict the general applicability of our findings to similar ICUs in large university hospitals. Selection bias occurred, since we did not include patients with subarachnoid hemorrhage, which has a better outcome compared to hemorrhagic and ischemic stroke. Third, we did not use specific stroke-severity scores (NIHSS,[11,38] intracerebral hemorrhage score, or neurosurgical scores),[40,41] which are not routinely determined in our ICU. Finally, we did not assess quality of life in survivors.
BMC Anesthesiol. 2022;22(235) © 2022 BioMed Central, Ltd.