[Effect of long-term and short-term mild hypothermia in severe traumatic brain injury: a comparative study]

To explore the effects of different mild hypothermia therapy time on the efficacy and complications of patients with severe traumatic brain injury (STBI).

A retrospective research method was used. 132 patients with STBI given mild hypothermia therapy admitted to the Third Affiliated Hospital of Gansu University of Traditional Chinese Medicine from January 2010 to December 2018 were enrolled. According to the days of mild hypothermia therapy, the patients were divided into 2-day mild hypothermia treatment group, 5-day mild hypothermia treatment group and 14-day mild hypothermia treatment group. Glasgow coma score (GCS) after treatment of 10 days and 30 days, 30-day disability rate and mortality, coma time, prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen (Fib), D-dimer, and the incidence of complications such as decreased blood pressure, decreased gastrointestinal motility, infection, nonunion of scalp, cerebrospinal fluid leakage, etc. were compared among three groups.

Among the 132 patients with STBI, there were 44 cases in the 2-day mild hypothermia treatment group, 45 cases in 5-day mild hypothermia treatment group, and 43 cases in 14-day mild hypothermia treatment group. There was no significant difference in gender, age, GCS score before treatment or time from injury to admission among three groups. Compared with 2-day mild hypothermia treatment group, the GCS score 10 days and 30 days after treatment in 5-day mild hypothermia treatment group and 14-day mild hypothermia treatment group were significantly higher (11.61±2.23, 10.17±2.03 vs. 6.79±1.49; 13.15±2.53, 11.24±2.24 vs. 8.79±1.59), the coma time were shorten (days: 5.79±1.89, 5.45±1.72 vs. 13.65±2.73), and 30-day disability rate and mortality were significantly decreased [13.33% (6/45), 11.63% (5/43) vs. 22.73% (10/44); 17.78% (8/45), 16.28% (7/43) vs. 31.82% (14/44)], PT and APTT were reduced obviously (s: 20.14±4.12, 22.54±3.56 vs. 30.67±5.19; 35.14±12.41, 38.59±13.54 vs. 56.67±10.62), Fib rose obviously (g/L: 1.84±0.25, 1.98±0.27 vs. 0.67±0.12), and D-dimer reduced obviously (mg/L: 53.10±19.84, 49.20±20.13 vs. 102.60±20.13), with statistically significant differences (all P < 0.05). But there was no significant difference in above indicators between the 5-day mild hypothermia treatment group and 14-day mild hypothermia treatment group (all P > 0.05). The incidence of complications in 14-day mild hypothermia group was significantly higher than those in 2-day mild hypothermia group and 5-day mild hypothermia group [decrease of blood pressure: 55.56% (20/36) vs. 36.67% (11/30), 35.14% (13/37); weakening of stomach intestinemotive power: 72.22% (26/36) vs. 46.67% (14/30), 45.95% (17/37); urethral infection: 52.78% (19/36) vs. 36.67% (11/30), 35.14% (13/37); lungs infection: 47.22% (17/36) vs. 36.67% (11/30), 37.84% (14/37); disunion of scalp: 5.56% (2/36) vs. 0% (0/30), 0% (0/37); leak of cerebrospinal fluid: 5.56% (2/36) vs. 0% (0/30), 0% (0/37), all P < 0.05], but there was no significant difference between the 2-day mild hypothermia treatment group and 5-day mild hypothermia treatment group (all P > 0.05).

The optimal time frame for mild hypothermia treatment in patients with STBI is 5-day, which shortens the coma time, and reduces the mortality and the disability rate. The shorter mild temperature time cannot effectively prevent secondary brain injury. However, the prolonged period of mild temperature will affect the repair of the patient's injury tissue, which is not conducive to the recovery of patient's mechanical function and is prone to complications.