Is Hypothermia Helpful in Severe Subarachnoid Hemorrhage? An Exploratory Study on Macro Vascular Spasm, Delayed Cerebral Infarction and Functional Outcome after Prolonged Hypothermia

Abstract

Background: Therapeutic hypothermia (TH) is an established treatment after cardiac arrest and growing evidence supports its use as neuroprotective treatment in stroke. Only few and heterogeneous studies exist on the effect of hypothermia in subarachnoid hemorrhage (SAH). A novel approach of early and prolonged TH and its influence on key complications in poor-grade SAH, vasospasm and delayed cerebral ischemia (DCI) was evaluated. Methods: This observational matched controlled study included 36 poor-grade (Hunt and Hess Scale >3 and World Federation of Neurosurgical Societies Scale >3) SAH patients. Twelve patients received early TH (<48 h after ictus), mild (35°C), prolonged (7 ± 1 days) and were matched to 24 patients from the prospective SAH database. Vasospasm was diagnosed by angiography, macrovascular spasm serially evaluated by Doppler sonography and DCI was defined as new infarction on follow-up CT. Functional outcome was assessed at 6 months by modified Rankin Scale (mRS) and categorized as favorable (mRS score 0-2) versus unfavorable (mRS score 3-6) outcome. Results: Angiographic vasospasm was present in 71.0% of patients. TH neither influenced occurrence nor duration, but the degree of macrovascular spasm as well as peak spastic velocities were significantly reduced (p < 0.05). Frequency of DCI was 87.5% in non-TH vs. 50% in TH-treated patients, translating into a relative risk reduction of 43% and preventive risk ratio of 0.33 (95% CI 0.14-0.77, p = 0.036). Favorable functional outcome was twice as frequent in TH-treated patients 66.7 vs. 33.3% of non-TH (p = 0.06). Conclusion: Early and prolonged TH was associated with a reduced degree of macrovascular spasm and significantly decreased occurrence of DCI, possibly ameliorating functional outcome. TH may represent a promising neuroprotective therapy possibly targeting multiple pathways of DCI development, notably macrovascular spasm, which strongly warrants further evaluation of its clinical impact.

Feasibility and Safety of Mild Therapeutic Hypothermia in Poor-Grade Subarachnoid Hemorrhage: Prospective Pilot Study

“…The mean time it took to reach the target temperature was faster in our study (4 hours to 34.5°C) compared with a previous study (48 hours to 35°C) (14). Most patients in the TH group were rewarmed for 45 hours.…”

“…Therefore, we induced TH in selected patients following proper intervention to secure the ruptured aneurysm and reduce the risk of bleeding. Nonetheless, TH was induced earlier (within 24 hours) in our study compared with previous studies (within 48 hours) (14). …”

“…The cooling procedure was initiated as soon as the catheter or cooling pad was installed after securing the ruptured aneurysm and continued until the core body temperature reached 34.5°C–35.0°C. The target temperature was 34.5°C, which avoided overcooling or severe complications (514). The core body temperature was recorded every hour using a thermometer at the tip of an esophageal probe.…”

What Do We Mean by Poor-Grade Aneurysmal Subarachnoid Hemorrhage and What Can We Do?

“…A few very interesting randomized trials are currently investigating neurocritical care measures beyond neurosurgery in or including SAH: EARLYDRAIN on early lumbar drainage combined with EVD [9], SETPOINT2 on early tracheostomy [10], NEWTON on slow-release nimodipine via EVD [11], ULTRA on early tranexamic acid [12], and HIMALAIA on induced hypertension [13]. However, there are so many other NCCU aspects to be addressed prospectively: level of sedation, modes of ventilation [14,15], cardiopulmonary stability [16,17], monitoring-based circulatory strategies [18], temperature control [19][20][21], delirium management, the nursing factor and mobilization, policies of do-not-resuscitate orders and withdrawal of care [22,23], and many other day-to-day care decisions that may substantially impact outcome. Particularly, the poor-grade SAH patient, prone to so many cerebral and systemic complications, may benefit from aggressive surveillance, superb nursing care, and close clinical monitoring.…”

Editorial

“…Stroke researchers and clinicians have to deal with local health networks [19,20], in- and pre-hospital patient triages [21,22] and stroke patients have to be identified while they are being treated for other diseases [23]. Acute stroke treatment now predominantly includes the time in an intensive care unit and we published some interesting manuscripts about this aspect [24,25,26,27]. We always have to identify stroke patients quickly without losing out on time and find the best suitable therapy for them in whatever condition they are - acute or chronic state.…”