TCI Versus Manual TIVA for Sedation During Prone Kyphoplasty: Effects on Respiration, Recovery, and EEG

Kyphoplasty is a minimally invasive spinal procedure commonly performed for osteoporotic vertebral compression fractures. The procedure involves balloon elevation of the collapsed vertebral body followed by injection of polymethylmethacrylate (PMMA) bone cement for stabilization. The procedure is performed in the prone position and typically involves 1-2 vertebral levels.

Total intravenous anesthesia (TIVA), using combinations of propofol and remifentanil, is an alternative to inhalation anesthesia. TIVA can be administered manually or via target-controlled infusion (TCI) systems. TCI systems use pharmacokinetic models to achieve and maintain targeted plasma or effect-site concentrations. Studies in endoscopy settings have demonstrated that TCI-based sedation provides more stable sedation depth, fewer hemodynamic fluctuations, and faster recovery compared to manual administration.

Kyphoplasty procedures are typically performed in elderly patients with multiple comorbidities in the prone position under fluoroscopic guidance. The prone position, while mandatory for kyphoplasty, presents significant anesthesia management challenges: limited airway access increases the risk of respiratory depression during sedation, and chest compression impairs ventilation mechanics and may reduce alveolar ventilation. Therefore, meticulous respiratory monitoring during kyphoplasty is essential.

The Capnostream® device records four variables (SpO₂, respiratory rate, non-invasive EtCO₂, and heart rate) every 30 seconds via a nasal cannula and integrates them into a single unitless value called the Integrated Pulmonary Index (IPI), ranging from 1 to 10. An IPI of 4 or below requires intervention, while 8-10 represents the normal range. Additionally, bispectral index (BIS) monitoring enables objective tracking of anesthesia depth through EEG waveform analysis.

This study aims to compare manual TIVA versus TCI methods regarding sedation depth, respiratory stability, hemodynamic parameters, and recovery in patients undergoing kyphoplasty in the prone position. The findings are expected to contribute to determining the optimal anesthesia approach in this patient population.

Inclusion criteria

• Age 18 years and older

• ASA physical status classification I-III
• Scheduled for kyphoplasty under sedation in the prone position
• Provision of written informed consent

Exclusion criteria

• Known allergy to any of the study medications

• ASA physical status classification IV or higher
• Patients deemed unsuitable for sedation (high pulmonary risk, morbid obesity, diagnosed severe obstructive sleep apnea)
• Refusal to participate or withdrawal of consent
• Diagnosis of dementia or Alzheimer's disease
• Communication difficulties precluding adequate assessment