Sedation protocols in non-traumatic SAH (SPRINT-SAH): A cross-sectional survey among German-speaking neurointensivists

Abstract

Background: In subarachnoid hemorrhage (SAH), titrating sedation to find a balance between wakefulness with the ability to perform valid clinical examinations on the one hand, and deep sedation to minimize secondary brain damage, on the other hand, is challenging. However, data on this topic are scarce, and current guidelines do not provide recommendations for sedation protocols in SAH.

Methods: We designed a web-based, cross-sectional survey for German-speaking neurointensivists to map current standards for the indication and monitoring of sedation, duration of prolonged sedation, and biomarkers for the withdrawal of sedation.

Results: Overall, 17.4% (37/213) of neurointensivists answered the questionnaire. Most of the participants were neurologists (54.1%, 20/37) and exhibited a long-standing experience in intensive care medicine (14.9 years, SD 8.3). Among indications for prolonged sedation in SAH, the control of intracranial pressure (ICP) (94.6%) and status epilepticus (91.9%) were most significant. With regard to further complications in the course of the disease, therapy refractory ICP (45.9%, 17/37) and radiographic surrogates of elevated ICP, such as parenchymal swelling (35.1%, 13/37), were the most relevant topics for experts. Regular awakening trials were performed by 62.2% of neurointensivists (23/37). All participants used clinical examination for the therapeutic monitoring of sedation depth. A total of 83.8% of neurointensivists (31/37) used methods based on electroencephalography. As a mean duration of sedation before attempting an awakening trial in patients with unfavorable biomarkers, neurointensivists suggested 4.5 days (SD 1.8) for good-grade SAH and 5.6 days (SD 2.8) for poor-grade SAH, respectively. Many experts performed cranial imaging before the definite withdrawal of sedation [84.6% (22/26)], and 63.6% (14/22) of the participants required an absence of herniation, space-occupying lesions, or global cerebral edema. The values of ICP tolerated for definite withdrawal were smaller compared to that of awakening trials (17.3 mmHg vs. 22.1 mmHg), and patients were required to stay below the threshold value for several hours (21.3 h, SD 10.7).

Conclusion: Despite the paucity of clear recommendations for sedation management in SAH in the pre-existing literature, we found some level of agreement indicating clinical efficacy for certain clinical practices. By mapping the current standard, this survey may help to identify controversial aspects in the clinical care of SAH and thereby streamline future research.

Keywords: SAH; deep sedation; intracranial hypertension; monitoring; withdrawal of sedation.

Figure 1

Indications and relevant biomarkers for prolonged sedation. (A) Relevance of SAH grading scales (World Federation of Neurological Surgeons (WFNS), Hunt and Hess, modified Fisher scale) to the guidance of sedation protocols [(B); n = 37; multiple selection of items]. Indications for prolonged sedation of patients in neurointensive care. Miscellaneous included non-neurointensive care-specific indications (pneumonia, sepsis) [(C); n = 37]. Ranking of predefined biomarkers according to their impact on the guidance of sedation protocols. Miscellaneous included ongoing refractory ICP elevation (n = 1, most important biomarker), reduction in brain tissue oxygen tension (PtbO2) monitoring (n = 2, second most important biomarker) as well as vegetative dysregulation, overall clinical impression, and no relevant other biomarkers (n = 2 and n = 1, respectively). TTM, targeted temperature management, ICP, intracranial pressure.

Figure 2

Relevance and safety criteria of daily awakening trials. (A) Proportion of experts performing daily awakening trials in patients in SAH (n = 37). (B) The proportion of experts applying pre-defined safety criteria for interruption of sedation. (C) Relevance of predefined safety criteria for interruption of sedation (n = 17, multiple selections). Miscellaneous included critical reduction in brain tissue oxygen tension (PtbO2, n = 2), status epilepticus (n = 1), and hypocapnia (pCO2 < 30mmHg, n = 1). (C) Thresholds of ICP, vegetative stress, and oxygen saturation. w/o, without, ICP; intracranial pressure.

Figure 3

Methods and thresholds for monitoring the level of sedation. (A) Methods used for monitoring the level of sedation (n = 37, multiple selections). (B) Methods used for monitoring via EEG-based techniques (n = 31, multiple selections). (C) Therapeutic targets using RASS as monitoring of the level of sedation (n= 37). (D) Therapeutic targets using BIS/EEG as monitoring of the level of sedation (BSR n =6; BIS n = 2). BSR was defined as the total time of suppression/epoch length × 100%. BIS, bispectral index, EEG, electroencephalography, BSR, burst suppression ratio.

Figure 4

Duration of sedation as a function of SAH biomarkers. The number of unfavorable biomarkers is represented on the y-axis, whereas the most important biomarker's value for the respective answering physician is coded on the x-axis [(A, B); n = 7]. Duration of sedation in patients with SAH as a function of the presence/absence of biomarkers in good-grade SAH (WFNS 1-3, Panel A) and poor-grade SAH (WFNS 4-5, Panel B). The one-gradient heatmap codes for the time of prolonged sedation in days [(C, D); n = 7]. The standard deviation of responses for the various clinical scenarios coded by a one-gradient heatmap.

Figure 5

Decision-making and thresholds of definite withdrawal of sedation. (A) Responsibilities of decision-making (n = 37), (B) proportion of neurointensivists demanding CT before the withdrawal of sedation (n = 26), (C) acceptable radiologic lesion patterns and thresholds for intracranial vasospasm (n = 22), and (D) and ICP in the context of definite withdrawal of sedation (n = 5 with 2 values excluded due to implausible values). SOP, standard operating procedure; GCE, global cerebral edema; MCA, middle cerebral artery; ICA, internal carotid artery; ICP, intracranial pressure.