Haemodynamic Effects and Complications of Continuous Versus Single-shot Spinal Anaesthesia for HIP Fracture Surgery

A Comparison of Haemodynamic Effects, as Assessed by Cardiac Output Monitoring, and Complications of Continuous Versus Single-Shot Spinal Anaesthesia for Hip-Fracture Surgery in Patients Over 50 Years of Age

This research project aims to identify a safer method of spinal anaesthesia for elderly patients undergoing surgical stabilisation of proximal femoral fractures.

The study's primary objective is to compare two spinal anaesthesia techniques: the continuous method (investigational), which allows titration of local anaesthetic doses through a catheter placed in the subarachnoid space, and the conventional single-shot bolus injection.

The main hypothesis is that the continuous catheter technique reduces the incidence of intraoperative hypotension and related complications, such as delirium, acute kidney injury, and cardiovascular events.

Beyond haemodynamic stability-assessed through advanced continuous monitoring of cardiac output and vascular resistance-the study will evaluate early and late complications, as well as quality of life up to 24 months post-surgery.

The project is a prospective, randomised, multicentre clinical trial including at least 216 patients over 50 years of age, randomly assigned to one of the two groups.

Proximal femoral fractures are a major and growing global health issue, particularly among geriatric patients with multiple comorbidities. The conventional single-shot spinal anaesthesia, though widely used, carries a high risk of hypotension, potentially leading to delirium, acute kidney injury, stroke, and cardiac events. These complications worsen prognosis, decrease quality of life, and increase mortality.

Most existing studies are over two decades old, based on small cohorts and outdated anaesthetic protocols, and lack long-term follow-up data (>30 days) on neurological outcomes, functional recovery, quality of life, and mortality. Moreover, no modern trials have provided direct, comprehensive comparisons between single-shot and continuous spinal anaesthesia.

This project therefore seeks to fill this critical evidence gap through a robust randomised clinical trial. Using precise, continuous measurements of arterial pressure, vascular resistance, and cardiac output, alongside long-term assessments of neurological outcomes, quality of life, and survival, it aims to determine whether continuous spinal anaesthesia offers superior safety and should become the new standard of care for this vulnerable population.

Study Flow Diagram.

1. Measured Variables, Measurement Scales, and Tools:

   • Orthopedic and Anesthesiological Qualification: Conducted according to the standard of care and existing procedures at the participating hospital.

   • Baseline Assessment: Performed using the following scales: ASA, Apfel, GCS, RASS, NRS, Bromage, Aldrete, CAM-ICU, and SF-36.

   • Baseline Neurological Assessment: Covering all neurological endpoints specified in the point 7

   • Anesthesia Method (determined by group randomization):

     1. Both groups: Ultrasound-guided femoral nerve block with 10 ml of 0.5% ropivacaine.
     2. Group 1 (Interventional): Continuous spinal anesthesia with titrated doses of 0.5% hyperbaric bupivacaine via an intrathecal catheter. An initial 1 ml induction dose will be administered, followed by 0.5 ml boluses every 15 minutes to achieve a sensory block to the T12 level. Once the block is established, the anesthetic level will be maintained with titrated doses of 0.5-1 ml approximately every hour. The operating table will be kept in a neutral position.
     3. Group 2 (Control): Single-shot spinal anesthesia with a bolus of 0.5% hyperbaric bupivacaine, with the dose adjusted according to the patient's weight and height to achieve a sensory block to the T12 level. The operating table will be kept in a neutral position.

2. Intraoperative Monitoring of Vital Signs:

   1. Standard Monitoring: Continuous measurement of heart rate (HR) via ECG and arterial oxygen saturation (SpO2) via pulse oximetry, as well as non-invasive blood pressure (NIBP) measured at 3, 5, and 15-minute intervals.

   2. Advanced Monitoring: Continuous invasive blood pressure (IBP); uncalibrated cardiac output (CO) measurement-calibrated with stroke volume (SV) calculated by echocardiography (LVOT x VTI*); and continuous measurement of stroke volume variation (SVV), pulse pressure variation (PPV), and systemic vascular resistance (SVR) throughout the intraoperative period.

      • Calculated as the product of the left ventricular outflow tract (LVOT) area and the velocity time integral (VTI), measured in the parasternal long-axis and apical 5-chamber views, respectively.

3. Monitoring in the Post-Anesthesia Care Unit (PACU):

   1. Continuation of standard vital signs monitoring (HR, BP, SpO2).
   2. Continuation of advanced hemodynamic monitoring if hemodynamic instability requires a continuous vasopressor infusion; patients will be transferred to the ICU if stabilization is not achieved.
   3. At discharge from PACU: Assessment using the GCS, RASS, NRS, Aldrete, CAM-ICU, and SF-36 scales, and a neurological assessment covering all endpoints specified in in the point 7 .

4. Monitoring on the Orthopedic Ward:

   a. At hospital discharge: An SF-36 assessment and a neurological assessment covering all endpoints specified in in the point 7 .

5. Assessment of Other Complications: The incidence of other in-hospital complications will be assessed according to established diagnostic criteria if they are suspected to have occurred.

6. Follow-up: Conducted at 1, 3, 6, 12, and 24 months post-intervention. A telephone interview will be performed to complete the SF-36 scale and conduct a neurological assessment covering all endpoints specified in the point 7 .

7. Complications associated with spinal anesthesia:

   1. Postoperative nausea and vomiting (PONV)
   2. Hypothermia
   3. Total spinal anesthesia
   4. Cardiac arrest
   5. Bladder dysfunction
   6. Back pain
   7. Transient neurological symptoms (TNS)
   8. Post-dural puncture headache (PDPH)
   9. Headache other than PDPH
   10. Peripheral nerve palsy
   11. Cauda equina syndrome
   12. Spinal hematoma or hygroma
   13. Intracranial hypotension syndrome
   14. Central nervous system infection
   15. Other

Inclusion Criteria:

• Age > 50 years, regardless of gender
• Diagnosis of a proximal femur fracture
• Orthopedic qualification for open reduction and internal fixation of the fracture
• Informed consent for the surgical procedure
• Informed consent for regional anesthesia, i.e., a central neuraxial block (spinal anesthesia)
• Informed consent to participate in the study

Exclusion Criteria:

• Age < 50 years, regardless of gender
• Refusal to consent to surgical treatment
• Refusal to consent to regional anesthesia
• Refusal to consent to participate in the study
• Inability to provide informed consent
• Allergy to local anesthetic agents
• Severe congenital or acquired coagulation disorders
• Failure to meet the recommended time interval between the last dose of an anticoagulant and central neuraxial blockade, according to the 2022 European Journal of Anaesthesiology (EJA) guidelines
• Infection at the block site or a systemic infection (i.e., sepsis, septic shock)
• Patients with multiple organ dysfunction syndrome requiring hospitalization in the Intensive Care Unit for stabilization of vital functions
• Clinical signs of increased intracranial pressure or suspicion of an intracranial mass on imaging studies
• Other contraindications to spinal anesthesia as judged by the qualifying physician