1.1 Study participants
This study has been approved by the Clinical Trial and Biomedical Ethics Committee of the West China Hospital of Sichuan University (approval number 2014 (238)). All patients signed informed consent. A total of 208 severe neuropathy patients who underwent craniocerebral surgery in the West China Hospital of Sichuan University from May 2015 to October 2018 were included (clinical trial registration number: ChiCTR-IOR-15006441). Patients were assigned to the experimental group and the control group according to the random number generated by the computerized random number table. The inclusion criteria were: patients (1) aged 18-75 years; (2) with cerebrovascular disease and undergoing craniocerebral surgery, including cerebrovascular diseases, intracranial tumors and severe brain injury, according to the diagnostic criteria of severe neuropathy; (3) with artificial airway and ventilator-assisted respiration; (4) equipped with intracranial pressure monitor; and (5) with the initial ICP of ≤ 25 mmHg. The exclusion criteria included: patients with (1) insufficient blood volume or unstable circulation; (2) hypotension; (3) shock; or (4) maternal patients.
1.2 Research methods
Severe neuropathy in this study included cerebrovascular disease, intracranial tumors, severe brain injury et al. And the patients were divided into various degrees according to the Glasgow Outcome Scale (GOS) . Patients in the both groups were treated by the same team of doctors and nurses. After the operation, both groups were treated with anti-inflammatory medications, ICP-reducing drugs, and nutritional support. All patients were subjected to the continuous ECG monitoring, oxygen inhalation. And the intracranial pressure monitor was installed beside the bed, so the digital changes and fluctuations of intracranial pressure could be observed directly. The control group was given ES directly without prior administration of propofol. The experimental group was sedated with propofol before ES. The dose of propofol was 0.5-1 mg/kg (10ml propofol with 1ml 2% lidocaine), and the injection was performed slowly. The patients were under sedation condition. And the doctors in our team were anesthesiologist qualified to manage the person at whatever level of sedation or anesthesia. For the ES procedure, patients were placed in a supine position, and the head of the bed was raised 15-30°. During the operation, No. 12 sputum suction tubes were used, the interval between consecutive ES was more than 30 minutes, and the negative pressure was set to 200 mmHg; the deep ES was performed [4-6, 32-33]. Each patient had ES applied at least 5 times.
1.3 Outcome measures
The changes in the vital signs, ES effect, the fluctuation range of ICP before and after ES, choking and coughing reaction, recent complications, prognosis score measured by the GOS six months after the procedure, the duration of in-hospital stay, and hospitalization expenses were compared between the two groups.
1.3.1 ES indications ES was considered necessary in the following cases: rapid breathing, high blood pressure, high airway pressure, cough, decreased SPO2, presence of secretions in the airway, and wheezy phlegm on auscultation [4-6,31,32].
1.3.2 Vital signs and SPO2 The vital signs and SPO2 were determined within 5 minutes after ES [6,27-29].
1.3.3 Measurement of ICP (mm H2O) fluctuation range The ICP fluctuation range was evaluated by the peak value of ICP during ES, the time to reach the peak value (seconds), the value of ICP after the recovery to a stable state, and the time to recover to a stable state (seconds).
1.3.4 Assessment of choking cough response The choking cough response was graded as follows: grade 1, no choking cough; grade 2, slight cough, 1-2 times, without apparent physical movement; grade 3, strong cough, 3-4 times, with neck and chest movement; grade 4, more than four coughs, accompanied by movement of the entire body and retching, and causing extreme pain [34,35].
1.3.5 Auscultation evaluation of the ES effect Three degrees of reduction of the wheeze phlegm were assigned: 1, complete disappearance; 2, significant decrease; and 3, partial decrease [6].
1.3.6 GOS
Six months after the procedure, the patients were evaluated using the GOS prognosis score [41-42]. The GOS scores of 4 and 5 indicated a good prognosis, and scores of 1-3 indicated poor prognosis [41-45].
1.4 Statistical analysis
The baseline measurement data were analyzed using the SPSS 22.0 software and were represented as the mean and standard deviation (x±s). The Student’s t-test was used for comparisons between the two groups. The enumeration data were represented as the composition ratio or percentage, and the chi-square test or Fisher's exact probability method was used for inter-group comparison. The rank data comparison was performed using the rank-sum test. The significant level was set at α = 0.05 (two-tailed), and P < 0.05 was considered statistically significant. Repeated measurement of quantitative data was analyzed by the SAS software. A random intercept-slope model that included grouping variables and measurement times was established.