To investigate the effects of different bedside angle on postoperative intracranial pressure and cerebral perfusion pressure in aSAH patients.

66 postoperative aSAH patients in the intensive care unit of Beijing Tiantan Hospital, Capital Medical University from September 2020 to April 2021 were selected as the research objects. The patients in a supine position at rest and raise the bedside angle by 0°, 10°, 20°, 30° and 40°) were kept in turn. Each position was held for 15 minutes, in which blood pressure, heart rate, respiration rate, pulse oxygen saturation and intracranial pressure were recorded after the data was stable. The average arterial pressure and cerebral perfusion pressure were calculated correspondingly. Prognostic related parameters including pressure injuries, hospital mortality, and Glasgow score at discharge, were also collected.

When the bedside angle were elevated at 0°, 10°, 20°, 30° and 40°, the intracranial pressure values were (17.76±5.54), (16.77±5.58), (15.94±5.85), (14.94±5.26), (14.35±5.33) mmHg (1 mmHg=0.133 kPa); the cerebral perfusion pressure were (79.31±12.08), (80.17±10.07), (81.94±11.96), (81.92±12.48), (82.53±12.30) mmHg, and the mean arterial pressure were (97.07±11.17), (96.94±9.43), (97.88±10.57), (96.86±11.56), (96.87±10.89) mmHg, respectively. The intracranial pressure decreased significantly with the increase of bedside angle from 0° to 30° (pairwise comparison showed P=0.001, P=0.050 and P=0.033), there was no significant difference in intracranial pressure between 30° and 40° (P=0.507). The cerebral perfusion pressure had a growing trend with the increase of the bedside angle from 0 ° to 40° (P=0.031), but there was no significant difference in all of pairwise comparison (P＞0.05). Mean arterial pressure did not change significantly with the increase of the degree of head elevation (P＞0.05). There was no statistically significant difference in vital signs of systolic blood pressure, diastolic blood pressure, heart rate, respiration rate and pulse oxygen saturation at different degrees of head elevations (P＞0.05). No pressure injury occurred in all patients during their ICU stay.

It may be a safe and effective therapeutic position to maintain the bedside angle at 30°-40° in aSAH patients to control intracranial pressure and ensure adequate cerebral perfusion. For patients with initially high intracranial pressure, raising the bedside angle to 40° may reduce intracranial pressure without increasing risks of pressure injuries.