Comparison of Total Intravenous Anesthesia Methods in Terms of Postoperative Outcomes in Thoracolumbar Spinal Surgery Cases
Conditions: Anesthesia
Sponsor: Dr Abdurrahman Yurtaslan Ankara Oncology Training and Research Hospital

Study Protocol 
 
Official Title: Comparison of Total Intravenous Anesthesia Methods in Patients Undergoing 
Neuromonitoring 
NCT Number: Pending 
Document Date: May 10, 2023 
 
Study Design and Methods 
Data from a total of 72 patients were collected. All patients included in the study were 
informed about the procedure, and their consent was obtained preoperatively. 
Routine Anesthesia Management: 
The routine anesthesia management administered by the neuroanesthesia team included 
premedication with midazolam at a dose of 0.02–0.04 mg/kg, standard anesthesia monitoring 
(pulse oximetry, non-invasive blood pressure, and electrocardiography), BIS monitoring 
(Medtronic COVIDIEN BIS™ Monitor), and preoxygenation. Anesthesia induction was 
performed using lidocaine (1 mg/kg bolus), remifentanil (1 µg/kg), propofol (2 mg/kg), and 
rocuronium (0.6 mg/kg). Invasive blood pressure monitoring and neuromonitoring were 
applied to all patients. 
For patients positioned prone, anesthesia maintenance was achieved with classical TIVA 
(50% oxygen-air mixture, propofol, and remifentanil infusions) or multimodal TIVA 
protocols incorporating ketamine, lidocaine, or dexmedetomidine, as determined by the 
anesthesiologist. Propofol and remifentanil infusion rates were adjusted to maintain a BIS 
score between 40 and 60 throughout the surgery. 
Post-induction, 0.1 mg/kg morphine HCL and 1 mg/kg methylprednisolone were administered 
for postoperative pain management, and 4 mg ondansetron was given at the end of surgery. 
Multimodal Drug Protocols: 
Intraoperative infusions were administered at fixed doses: lidocaine (1.2 mg/kg/h), ketamine 
(5 mcg/kg/min), and dexmedetomidine (0.2 mcg/kg/h). 
Monitored Parameters: 
 
Demographic and Clinical Data: Age, gender, weight, comorbidities, ASA 
classification, surgery duration, and the number of stabilization levels were recorded. 
 
Intraoperative Monitoring: Blood pressure, heart rate, BIS values, and cardiac 
events (bradycardia/tachycardia, arrhythmia, hypotension/hypertension) were 
documented at baseline and at 30, 60, 120, and 180 minutes post-induction. The total 
doses of propofol, remifentanil, and other drugs used were noted at the end of surgery. 
Additionally, adverse events such as laryngospasm, bronchospasm, muscle rigidity, 
agitation, or shivering were recorded post-extubation. 
 
Postoperative Monitoring: Hemodynamic parameters (blood pressure, heart rate), 
nausea/vomiting occurrence, and Ramsey sedation scores were recorded at 30 
minutes, 2, 6, 12, and 24 hours postoperatively (Table 1). If nausea/vomiting occurred, 
the administered treatment was documented. Pain intensity was evaluated using the 

Visual Analog Scale (VAS, 0 = no pain, 10 = worst pain) (Figure 1). Total drug usage 
over 24 hours postoperatively was calculated as morphine equivalents (Table 2). 
 
 
 
 
Table.1 Ramsey Sedation Scala 
Score 
Clinical Condition 
1 
Awake, anxious, agitated, or restless 
2 
Awake, cooperative, oriented, and calm 
3 
Responds to verbal commands 
4 
Asleep, but responds quickly to light glabellar tapping 
5 
Asleep, responds slowly to verbal or physical stimuli 
6 
No response to painful stimuli 
Recovery and Follow-Up Parameters: 
 
The first oral intake time, time to first bowel movement, time to first ambulation, and 
length of hospital stay were recorded. Gastrointestinal recovery was defined as the 
first time the patient reported passing gas or having a bowel movement. Hospital stay 
was calculated from the time the patient left the operating room to discharge. 
 
Patients were monitored for drug-related side effects (e.g., perioral numbness, tingling, 
dizziness, tinnitus, diplopia, seizures, arrhythmia, extremity numbness, muscle 
twitching, color perception changes, blurred vision, hallucinations). 
 
On postoperative day 30, patients were contacted via telephone to assess opioid 
requirements after discharge.  
 
 
 
 
 
Table 2.  Opioid Rotation Doses 
Drug 
Route of Administration Unit Dose 
Morphine 
IV/IM/SC 
mg 10 
Meperidine IV 
mg 75 
Tramadol 
IV 
mg 100 

 
Sample Size: 
Based on previous studies, a power analysis determined that 24 patients per group were 
needed to detect a 10 mm difference in VAS pain scores with a two-tailed α = 0.05 and 80% 
power.