Variation Of Postoperative Brain Temperature In Patients With Poor-grade Aneurysmal Subarachnoid Hemorrhage And Its Significance

Obejctive To investigate the basic characteristics of variations of postoperative brain temperature in patients with poor-grade aneurysmal subarachnoid hemorrhage and the relationship between brain temperature and monitoring parameters such as core body temperature and intracranial pressure through a single-center prospective observational study..Methods A total of 23 patients with from poor-grade aneurysmal subarachnoid hemorrhage in the Department of Neurosurgery of Wuxi Clinical College of Anhui Medical University were enrolled from January 2018 to July 2022.All patients underwent craniotomy for aneurysm clipping.Patients were divided into spontaneous hypothermia group(N=8)as well as normothermia group(N=15)according to the different clinical presentations.The patients were admitted into the neurological intensive care unit(NICU)immediately after surgery.The brain temperature and intracranial pressure were continuously measured using a ventricular-type intracranial pressure probe.Rectal temperature was measured as core temperature using an electronic temperature probe.Patients’ brain temperature,core temperature,intracranial pressure and blood pressure were recorded once an hour,and the data were analyzed.Results All patients underwent multimodal neurological functional monitoring after surgery.1.When studying postoperative brain temperature variation in patients,patients in the SH group showed a gradual decline in brain temperature during the first postoperative 24 hours(from 35.99±1.42℃ to 33.60±1.95℃).Patients in the normothermia group showed a certain rhythmical of brain temperature(fluctuating between 37.67℃-37.96℃)during the first 24 hours after surgery.Brain temperature of patients in the normothermia group was recorded continuously for the postoperative 10 days.The brain temperature was relatively stable(37.70-37.80℃)on postoperative days 1 to 2.On days 3 to 5,it increased rapidly to 38.36±0.50℃.On days 5 to 8,it remained around 38.40°C.The brain temperature showed a decrease on postoperative day 9(from 38.34±0.52℃ to 38.14±0.66℃).2.When studying the correlation between brain temperature and core temperature,brain temperature correlated with core temperature in patients in both the spontaneous hypothermia and normothermia groups during the first 24 hours after surgery.The correlation coefficient was higher in the normothermia group than in the spontaneous hypothermia group(r=0.802 vs.r=0.868).During the postoperative 10 days,the correlation between brain temperature and core temperature was slightly lower in the normothermia group of patients(r=0.696).3.When studying postoperative intracranial pressure variations in patients,both groups showed an increasing trend in intracranial pressure during the first postoperative 24 hours.Patients in the spontaneous hypothermia group showed a significant increase in intracranial pressure(40.88 mm Hg-69.38 mm Hg),while intracranial pressure in the normothermic patient group increased slightly,and remained within the normal range(8.80 mm Hg-13.33 mm Hg).Intracranial pressure of patients in the normothermia group also showed an increasing tendency during the postoperative 10 days.On days 1 to 4,the intracranial pressure rose slightly(10.68 mm Hg-11.56 mm Hg).The intracranial pressure rose rapidly and peaked on day 5(12.99±3.68 mm Hg).On days 5 to 7 the intracranial pressure was maintained at a high level(12.48 mm Hg-12.99 mm Hg),and it began to decrease continuously on day 8(dropped to 10.34 mm Hg).4.When study the relationship between brain temperature and intracranial pressure,intracranial pressure showed a biphasic pattern with variations in brain temperature.The intracranial pressure of patients in the spontaneous hypothermia group increased sharply with the decrease of brain temperature,and increased to 66.46±16.44 mm Hg when the brain temperature dropped below 34°C.In the normothermic therapy group,on the contrary,the intracranial pressure increased slowly with the increase of brain temperature,and increased to 13.08±1.84 mm Hg when the brain temperature increased to 38.3°C.The relationship between brain temperature and intracranial pressure of patients in the normothermia group of the patients in the normothermic group also maintained the same trend at 10 days postoperatively.Conclusion The brain temperature and intracranial pressure of patients with poor-grade aneurysmal subarachnoid hemorrhage tend to increase after surgery.Increased brain temperature may lead to increased intracranial pressure,which may result in a poor prognosis.However,severe intracranial hypertension can reduce cerebral metabolism by decreasing cerebral blood flow and resulted in decreased brain temperature,and this is also a sign of poor prognosis.Brain temperature is a visible indicator of intracranial conditions and to some extent,can be a new therapeutic target.