[Effect of transnasal humidified rapid insufflation ventilatory exchange on cerebral oxygen saturation during induction of general anesthesia in patients undergoing traumatic brain injury emergency surgery].

Abstract

Objective: To evaluate the effect of transnasal humidified rapid insufflation ventilatory exchange (THRIVE) on regional cerebral oxygen saturation (rScO₂) during induction of general anesthesia in patients undergoing traumatic brain injury (TBI) emergency surgery.

Methods: A prospective randomized controlled trial was conducted. The TBI emergency general anesthesia patients who underwent intracranial hematoma removal surgery at the Northern Jiangsu People's Hospital from January to July in 2023 were enrolled. The patients were divided into a conventional mask ventilation group and a THRIVE group using a random number table method. The patients in the conventional mask ventilation group were anesthetized and induced to pre oxygenate without positive pressure ventilation in the front mask for 10 minutes, with an oxygen flow rate of 8 L/min and an fraction of inspired oxygen (FiO₂) of 1.00. After anesthesia induction for about 90 s, tracheal intubation was performed after the muscle relaxant took effect (patient's jaw muscle was relaxed). The patients in the THRIVE group were pre oxygenated with THRIVE for 10 minutes, with an oxygen flow rate of 30 L/min and a FiO₂ of 1.00. During anesthesia induction, the oxygen flow rate was increased to 50 L/min, and anesthesia induction medication was used. The lower jaw of patient was supported with both hands to maintain airway patency, and the patient's mouth was kept closed throughout the process. After the muscle relaxant took effect (the patient's jaw muscle was relaxed), tracheal intubation was performed. At the time of patient entering the operating room, 10 minutes of pre oxygenation, and immediately after successful intubation, rScO₂ was measured on the surgical and non-surgical sides. At the same time, ultrasound was used to measure the cross-sectional area (CSA) of the gastric antrum and arterial blood gas analysis was performed. The partial pressure of end-tidal carbon dioxide (P_ETCO₂) during the first mechanical ventilation after successful tracheal intubation, the incidence of hypoxemia [pulse oxygen saturation (SpO₂) < 0.95] during tracheal intubation, as well as prognostic indicators such as the length of intensive care unit (ICU) stay, total length of hospital stay, and Glasgow outcome scale (GOS) score at discharge were recorded.

Results: During the study period, a total of 70 TBI patients underwent emergency general anesthesia surgery, of which 2 patients died postoperatively, 2 patients were unable to cooperate with closed mouth breathing, and 3 patients had poor ultrasound image acquisition in the gastric antrum, all of whom were excluded. A total of 63 patients were ultimately enrolled, including 32 in the conventional mask ventilation group and 31 in the THRIVE group. There were no statistically significant differences in gender, age, body mass index (BMI), American Society of Anesthesiologists (ASA) classification, Glasgow coma scale (GCS) score, optic nerve sheath diameter (ONSD), baseline vital signs, fasting situation, anesthesia time, surgical time, and intraoperative blood loss between the patients in the two groups, indicating comparability. When entering the operating room, there was no statistically significant difference in rScO₂ on the surgical and non-surgical sides, and blood gas analysis indexes arterial partial pressure of oxygen (PaO₂) and arterial partial pressure of carbon dioxide (PaCO₂) between the patients in the two groups. When pre oxygenated for 10 minutes, both the surgical and non-surgical sides rScO₂ levels in the THRIVE group were significantly higher than those in the conventional mask ventilation group (surgical side: 0.709±0.036 vs. 0.636±0.028, non-surgical side: 0.791±0.016 vs. 0.712±0.027, both P < 0.01), and the PaO₂ was significantly increased [mmHg (1 mmHg ≈ 0.133 kPa): 450.23±60.99 vs. 264.88±49.33, P < 0.01], PaCO₂ was significantly reduced (mmHg: 37.81±3.65 vs. 43.59±3.76, P < 0.01), and the advantage continues tilled immediately after successful intubation. There was no statistically significant difference in CSA at each time point of ultrasound examination between the two groups. Compared with the conventional mask ventilation group, the patients in the THRIVE group showed a significant decrease in P_ETCO₂ during the first mechanical ventilation after successful tracheal intubation (mmHg: 43.10±2.66 vs. 49.22±3.31, P < 0.01), and the incidence of hypoxemia during tracheal intubation was also significantly reduced [0% (0/31) vs. 28.12% (9/32), P < 0.01]. In terms of prognostic indicators, there was no statistically significant difference in the length of ICU stay and total length of hospital stay between the patients in the conventional mask ventilation group and the THRIVE group [length of ICU stay (days): 10 (9, 10) vs. 10 (9, 11), total length of hospital stay (days): 28.00 (26.00, 28.75) vs. 28.00 (27.00, 29.00), both P > 0.05]. However, the proportion of patients in the THRIVE group with a good prognosis at discharge (GOS score > 3) was significantly higher than that in the conventional mask ventilation group [35.5% (11/31) vs. 12.5% (4/32), P < 0.05].

Conclusions: THRIVE can significantly increase rScO₂ during anesthesia induction in TBI emergency surgery patients and improve their neurological function prognosis.