What keeps patients with subarachnoid hemorrhage in the neurosciences ICU

Anticipated neurological intensive care unit length of stay is of interest to intensivists, administrators, patient families, neurologists, and neurosurgeons alike. Although some may equate length of stay with outcome, a measure more commonly addressed in the literature, these are two distinct entities. Patients with poor outcomes may have very brief lengths of stay as a result of early redirection of care, and thus, the issue of length of stay encompasses patients that, despite successful and aggressive care, may continue to serve as an ongoing challenge to intensivists. Intuitive neurological factors that prolong length of stay after aneurysmal subarachnoid hemorrhage include the vasospasm period and hydrocephalus. The severity of the former is influenced by patient age [1, 2], presenting clinical grade [3, 4], amount of subarachnoid blood [3, 4], and, as has been elegantly demonstrated by another recent post hoc analysis of CONSCIOUS-1, treatment modality [5]. However, the duration of the vasospasm period is not only influenced by these factors; it may also be influenced by varying vasospasm protocols as more aggressive approaches such as balloon angioplasty may shorten the period. At the conclusion of the vasospasm period, weaning of a ventriculostomy and/or placement of a shunt may be another factor prolonging ICU stay. Aside from neurological factors, medical conditions that arise as a result of subarachnoid hemorrhage such as severe myocardial stunning or neurogenic pulmonary edema may also prolong ICU stay. Of course, medical co morbidities in themselves particularly pre-existing cardiac conditions which may be stressed by the vasospasm period or respiratory conditions that may be stressed by altered mental status, pulmonary edema, pneumonia, and aggressive hydration may also prolong ICU stay. Of course, a long ICU stay in itself can ‘‘lengthen’’ ICU stay as a result of thromboembolic or infectious complications. However, many of these medical factors arise as time in the ICU passes and thus, to better counsel patient families and plan for aggressive care, early predictors of prolonged ICU stay are important to identify. Witiw and colleagues from the University of Toronto have performed an interesting post hoc analysis of patients in CONSCIOUS-1 [6] to elucidate factors on admission associated with prolonged length of stay after aneurysmal SAH. They found that age, clinical grade, pre-existing hypertension, intraparenchymal hemorrhage, and intraventricular hemorrhage were associated with prolonged critical care stays. Although increasing age may be protective from the perspective of vasospasm, it is intuitively deleterious from the perspective of arising medical co morbidities prolonging ICU stay and has sensibly arisen as a factor prolonging ICU stay. Clinical grade at presentation is a surrogate for hydrocephalus and is known to correlate with vasospasm [3, 4]—it is thus not at all surprising that this correlated with ICU length of stay as has been demonstrated in another smaller study [7]. As the authors only evaluated hypertension and hyperglycemia as potential presenting medical co morbidities, it is not surprising that associated-hypertension was significant, as this is likely a surrogate for other medical co morbidities that were not specifically evaluated. Intraventricular hemorrhage arising as a significant factor prolonging ICU stay is also sensible from the perspective of a greater proclivity toward ventriculostomy/shunt dependence. Interestingly, although ‘‘hydrocephalus’’ itself did not impact ICU stay in this B. A. Gross (&) Brigham and Women’s Hospital, Harvard Medical School, 75 Francis St, Boston, MA 02115, USA e-mail: bgross1@partners.org