This randomized controlled study aims to compare the intraoperative hemodynamic effects of unilateral and bilateral spinal anesthesia in elderly patients undergoing elective total hip arthroplasty. Seventy-four patients aged 65 years and older will be randomized into two groups: unilateral spinal anesthesia (n=37) and bilateral spinal anesthesia (n=37).
Hemodynamic parameters including cardiac output, stroke volume, stroke volume variation, pulse pressure variation, and systemic vascular resistance will be continuously monitored using the Pressure Recording Analytical Method (PRAM)-based MostCare monitoring system. Intraoperative fluid requirements and vasopressor consumption will also be evaluated.
The study seeks to determine whether unilateral spinal anesthesia provides greater hemodynamic stability and reduces the need for fluid administration and vasopressor support compared with conventional bilateral spinal anesthesia in elderly patients undergoing hip arthroplasty.
Eligibility
Sex
ALL
Min age
65 Years
Max age
—
Healthy volunteers
No
Inclusion Criteria:
1. Adults aged 65 years and older.
2. Patients scheduled for elective total hip arthroplasty.
3. Patients with an American Society of Anesthesiologists (ASA) physical status classification of II, III, or IV.
4. Patients with a Glasgow Coma Scale (GCS) score of 13-15 who are conscious and able to cooperate.
5. Patients with suitable peripheral arterial anatomy for PRAM monitoring.
6. Patients who provide written informed consent to participate in the study.
7. Patients without any clinical contraindication to spinal anesthesia. -
Exclusion Criteria:
1. Glasgow Coma Scale (GCS) score \<13.
2. Age below 65 years.
3. History of previous major neurosurgical intervention.
4. Anatomical abnormality, vascular defect, or infection at the site intended for arterial catheter placement for PRAM monitoring.
5. Severe spinal deformity (e.g., severe scoliosis, previous spinal fusion surgery, or spinal trauma).
6. Current anticoagulant therapy or coagulopathy (INR \>1.5 or platelet count \<75,000/mm³).
7. Presence of skin infection or systemic infection/sepsis.
8. Severe hypovolemia or decompensated cardiac disease in which spinal anesthesia is contraindicated.
9. Known allergy or hypersensitivity to local anesthetics or sedative agents.
10. Local infection or wound at the planned spinal puncture site.
11. Clinical contraindication to spinal anesthesia (e.g., increased intracranial pressure, septicemia, or severe hypotension). -
Primary outcome measure(s)
Cardiac Index Measured Using PRAM During Spinal Anesthesia — From immediately before spinal anesthesia until completion of surgery, assessed at baseline and every 10 minutes for up to 180 minutes. Cardiac index will be measured using the Pressure Recording Analytical Method (PRAM) and reported in L/min/m². Measurements recorded at each study time point will be compared between the unilateral and bilateral spinal anesthesia groups.
Stroke Volume Index Measured Using PRAM During Spinal Anesthesia — From immediately before spinal anesthesia until completion of surgery, assessed at baseline and every 10 minutes for up to 180 minutes. Stroke volume index will be measured using the Pressure Recording Analytical Method (PRAM) and reported in mL/beat/m². Measurements recorded at each study time point will be compared between the unilateral and bilateral spinal anesthesia groups.
Stroke Volume Variation Measured Using PRAM During Spinal Anesthesia — From immediately before spinal anesthesia until completion of surgery, assessed at baseline and every 10 minutes for up to 180 minutes. Stroke volume variation will be measured using the Pressure Recording Analytical Method (PRAM) and reported as a percentage. Measurements recorded at each study time point will be compared between the unilateral and bilateral spinal anesthesia groups.
Pulse Pressure Variation Measured Using PRAM During Spinal Anesthesia — From immediately before spinal anesthesia until completion of surgery, assessed at baseline and every 10 minutes for up to 180 minutes. Pulse pressure variation will be measured using the Pressure Recording Analytical Method (PRAM) and reported as a percentage. Measurements recorded at each study time point will be compared between the unilateral and bilateral spinal anesthesia groups.
Systemic Vascular Resistance Measured Using PRAM During Spinal Anesthesia — From immediately before spinal anesthesia until completion of surgery, assessed at baseline and every 10 minutes for up to 180 minutes. Systemic vascular resistance will be measured using the Pressure Recording Analytical Method (PRAM) and reported in dyn·s/cm⁵. Measurements recorded at each study time point will be compared between the unilateral and bilateral spinal anesthesia groups.
Oxygen Delivery Index Measured Using PRAM During Spinal Anesthesia — From immediately before spinal anesthesia until completion of surgery, assessed at baseline and every 10 minutes for up to 180 minutes. Oxygen delivery index will be measured using the Pressure Recording Analytical Method (PRAM) and reported in mL/min/m². Measurements recorded at each study time point will be compared between the unilateral and bilateral spinal anesthesia groups.
Arterial Elastance Measured Using PRAM During Spinal Anesthesia — From immediately before spinal anesthesia until completion of surgery, assessed at baseline and every 10 minutes for up to 180 minutes. Arterial elastance will be measured using the Pressure Recording Analytical Method (PRAM) and reported in mmHg/mL. Measurements recorded at each study time point will be compared between the unilateral and bilateral spinal anesthesia groups.
Maximum Rate of Arterial Pressure Rise Measured Using PRAM — From immediately before spinal anesthesia until completion of surgery, assessed at baseline and every 10 minutes for up to 180 minutes. The maximum rate of arterial pressure rise (dP/dtmax) will be measured using the Pressure Recording Analytical Method (PRAM) and reported in mmHg/s. Measurements recorded at each study time point will be compared between the unilateral and bilateral spinal anesthesia groups.
Cardiac Cycle Efficiency Measured Using PRAM — From immediately before spinal anesthesia until completion of surgery, assessed at baseline and every 10 minutes for up to 180 minutes. Cardiac cycle efficiency (CCE) will be measured using the Pressure Recording Analytical Method (PRAM) and reported as a dimensionless value. Measurements recorded at each study time point will be compared between the unilateral and bilateral spinal anesthesia groups.
Oxygen Delivery Measured Using PRAM During Spinal Anesthesia — From immediately before spinal anesthesia until completion of surgery, assessed at baseline and every 10 minutes for up to 180 minutes. Oxygen delivery (DO₂) will be measured using the Pressure Recording Analytical Method (PRAM) and reported in mL/min. Measurements recorded at each study time point will be compared between the unilateral and bilateral spinal anesthesia groups.
Mean Arterial Pressure During Spinal Anesthesia — From immediately before spinal anesthesia until completion of surgery, assessed at baseline and every 10 minutes for up to 180 minutes. Mean arterial pressure (MAP) will be measured using invasive arterial pressure monitoring and reported in mmHg. Measurements recorded at each study time point will be compared between the unilateral and bilateral spinal anesthesia groups.
Heart Rate During Spinal Anesthesia — From immediately before spinal anesthesia until completion of surgery, assessed at baseline and every 10 minutes for up to 180 minutes. Heart rate (HR) will be recorded using standard perioperative monitoring and reported in beats per minute. Measurements recorded at each study time point will be compared between the unilateral and bilateral spinal anesthesia groups.
Peripheral Oxygen Saturation During Spinal Anesthesia — From immediately before spinal anesthesia until completion of surgery, assessed at baseline and every 10 minutes for up to 180 minutes. Peripheral oxygen saturation (SpO₂) will be measured using pulse oximetry and reported as a percentage. Measurements recorded at each study time point will be compared between the unilateral and bilateral spinal anesthesia groups.
This page summarises publicly available registry data for informational purposes — not medical advice. Eligibility is determined by each study team; patients should discuss participation with their clinician.
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