Optimizing the Paracetamol Dose for Prevention of Post-Spinal Shivering in Lower Limb Orthopedic Surgeries
Optimizing the Paracetamol Dose for Prevention of Post-Spinal Shivering in Lower Limb Orthopedic Surgeries: A Randomized Controlled Trial
Shivering is a common and distressing complication following spinal anesthesia, affecting up to 70% of patients. It significantly increases oxygen consumption, places stress on the cardiovascular system, and interferes with postoperative monitoring. While intravenous paracetamol has been shown to reduce post-spinal shivering without the sedation or respiratory side effects associated with other medications, existing trials have only investigated a standard 1-gram dose. This study aims to evaluate whether a higher dose of intravenous paracetamol (2 grams) provides superior prevention of post-spinal shivering compared to the standard 1-gram dose and an inactive placebo.
Adult patients scheduled for elective lower-limb orthopedic surgery under spinal anesthesia will be randomly allocated to one of three study groups:
- High-dose group: intravenous paracetamol 2 g
- Standard-dose group: intravenous paracetamol 1 g
- Control group: intravenous normal saline placebo
Each infusion will be administered over 15 minutes immediately prior to spinal anesthesia. Participants will be observed intraoperatively and for at least 60 minutes in the post-anesthesia care unit (PACU) to measure the incidence and severity of shivering, core body temperature changes, the need for rescue medication, and any adverse events.
Study Overview
Status
Conditions
Intervention / Treatment
Study Type
Enrollment (Estimated)
Phase
- Phase 4
Participation Criteria
Eligibility Criteria
Ages Eligible for Study
Accepts Healthy Volunteers
Genders Eligible for Study
Description
Inclusion Criteria:
- Age 18 to 65 years
- American Society of Anesthesiologists (ASA) physical status I or II
- Scheduled for elective lower-limb orthopedic surgery under spinal anesthesia
- Expected surgical duration between 1 and 3 hours
- Willingness to provide written informed consent
Exclusion Criteria:
- Patient refusal or inability to provide informed consent
- ASA physical status >= III
- Contraindications to spinal anesthesia (e.g., coagulopathy, local infection at injection site, severe spinal deformity)
- Known allergy or hypersensitivity to paracetamol or the local anesthetic used
- Baseline (preoperative) core/tympanic temperature < 36.5°C or > 37.5°C
- Pre-existing hepatic, renal, or thyroid disorders
- History of seizure disorder
- Chronic alcohol use, malnutrition, or any condition predisposing to hepatotoxicity
- Body mass index (BMI) > 35 kg/m²
- Pregnancy or lactation
- Chronic use of antipyretic or anti-inflammatory medication within 24 hours of surgery
- Cardiac arrhythmia or hemodynamic instability
Study Plan
How is the study designed?
Design Details
- Primary Purpose: Prevention
- Allocation: Randomized
- Interventional Model: Parallel Assignment
- Masking: Quadruple
Arms and Interventions
Participant Group / Arm |
Intervention / Treatment |
|---|---|
|
Experimental: Group H: High-Dose Paracetamol (2 g)
Patients receive intravenous paracetamol 2 g diluted in 500 mL volume, infused over 15 minutes, commencing immediately prior to intrathecal injection. |
Intravenous paracetamol 2 g in 500 mL volume, administered as an intravenous infusion over 15 minutes immediately prior to intrathecal injection. |
|
Active Comparator: Group S: Standard-Dose Paracetamol (1 g)
Patients receive intravenous paracetamol 1 g diluted in 500 mL volume, infused over 15 minutes, commencing immediately prior to intrathecal injection. |
Intravenous paracetamol 1 g in 500 mL volume, administered as an intravenous infusion over 15 minutes immediately prior to intrathecal injection. |
|
Placebo Comparator: Group C: Placebo Control
Patients receive 500 mL of intravenous normal saline (0.9% sodium chloride), infused over 15 minutes, commencing immediately prior to intrathecal injection. |
Intravenous 0.9% normal saline 500 mL, infused over 15 minutes immediately prior to intrathecal injection, matched in volume and appearance to preserve blinding. |
What is the study measuring?
Primary Outcome Measures
Outcome Measure |
Measure Description |
Time Frame |
|---|---|---|
|
Percentage of Participants With Clinically Significant Post-Spinal Shivering
Time Frame: Up to 4 hours post-spinal injection
|
Clinically significant shivering is defined as a shivering score >= 3 on the Crossley and Mahajan Shivering Grading Scale. The scale ranges from Grade 0 to Grade 4: Grade 0 = No shivering; Grade 1 = Piloerection or peripheral vasoconstriction without visible muscular activity; Grade 2 = Muscular activity confined to one muscle group; Grade 3 = Muscular activity involving more than one muscle group, but not generalized; Grade 4 = Gross muscular activity involving the whole body. Higher grades indicate greater shivering severity. |
Up to 4 hours post-spinal injection
|
Collaborators and Investigators
Sponsor
Study record dates
Study Major Dates
Study Start (Estimated)
Primary Completion (Estimated)
Study Completion (Estimated)
Study Registration Dates
First Submitted
First Submitted That Met QC Criteria
First Posted (Actual)
Study Record Updates
Last Update Posted (Actual)
Last Update Submitted That Met QC Criteria
Last Verified
More Information
Terms related to this study
Keywords
Additional Relevant MeSH Terms
Other Study ID Numbers
- Paracetamol Dose for Shivering
Drug and device information, study documents
Studies a U.S. FDA-regulated drug product
Studies a U.S. FDA-regulated device product
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