Low Dose Spinal Bupivacaine for Total Knee Replacement and Recovery Room Wait Time

Queen's University

Status

Completed

Conditions

Spinal Anesthesia

Total Knee Arthroplasty

Treatments

Drug: Standard dose bupivacaine in spinal anesthetic

Drug: Low dose bupivicaine in spinal anesthetic

Study type

Interventional

Funder types

Other

Identifiers

NCT00537472

6106

Details and patient eligibility

About

This study plans to investigate whether a reduced dose of bupivacaine (a local anesthetic numbing drug) injected into the spinal space for a total knee replacement will result in a shorter time to discharge from the recovery room while maintaining adequate surgical anesthesia.

Full description

With the doses of bupivacaine currently being used in spinal anesthetics at our institution, patients' sensory blocks are often much higher than needed to achieve adequate surgical anesthesia. This translates into a prolonged waiting period in the recovery room before the level regresses down to the pre-existing standard for discharge to the ward, as well as the pre-existing level before a post-operative nerve block for extended pain relief can be performed. This prolonged period in the recovery room leads to general delays in operating room usage and thus surgical cancellations. The excessive drug doses currently used also put patients at risk for increasing side effects including low blood pressure, slow heart rates, and nausea and vomiting.

By using a reduced dose of bupivacaine in a spinal anesthetic for a one sided knee replacement, we hope to significantly reduce the recovery room waiting times until the criteria for recovery room discharge or completion of a post-operative nerve block are met, while still providing adequate surgical anesthesia.

Patients will receive either 9 mg (intervention dose) or 13 mg (control dose) of bupivacaine through a spinal injection. Once the patients enter the recovery room after surgery the level of their sensory block will be tested as per usual protocol by the recovery room nurses every 15 minutes until a predefined level has been reached, and the two groups will be compared.

Enrollment

140 patients

Sex

All

Volunteers

No Healthy Volunteers

Inclusion criteria

Patients undergoing elective one-sided total knee replacement for osteoarthritis at our institution where spinal anesthesia has been chosen by the patient and the anesthetist

Exclusion criteria

Contraindications to spinal anesthesia (such as increase pressure in brain, bleeding disorder, serious valvular heart disease, serious infection in the blood or on your lower back, certain neurological disorders such as multiple sclerosis, desire for a general anesthetic)
Allergies to local anesthetics, morphine or fentanyl
Both knees being done at same surgery
Revision of a previous knee replacement
Knee replacement for reasons other than osteoarthritis (such as rheumatoid arthritis)
Potential for difficult intubation in case of need for general anesthetic
Patients under 150 cm or over 200 cm
BMI greater than 40
Lack of patient consent or patient refusal