Pain management after total hip replacement is one of the most important aspects of postoperative care for patients and clinicians alike. One of the most common techniques used in anesthesia for this procedure is spinal anesthesia with concurrent administration of opioids into spinal sac. Addition of opioids not only prolongs the anesthesia but also provides pain relief after the procedure for a limited amount of time. Because of its unique chemical properties morphine provides the longest pain relief amongst currently known opioids lasting up to 24 hours. Unfortunately this beneficial effect is associated with both minor and serious adverse effects, most important of which is respiratory depression.
To limit this potenitialy fatal adverse effect dosing of morphine must be very precise in order to balance advantages and risks.
The aim of the study was to assess effectiveness and safety profile of different doses of morphine administered during spinal anesthesia for pain control.
Informed consent to participate in trial
Qualification for total hip replacement surgery
ASA physical status I-III
BMI 19-30
Incapability to provide informed consent
Contraindications for spinal anesthesia
Preoperative chronic pain
Chronic use of analgesics
Parallel
Spinal Anesthesia (bupivacaine)
Procedure/SurgeryPatients were positioned in sitting position on operating table, interspinous space was identified using anatomical landmarks (intercristal line) and palpation. Entire procedure was conducted with aseptic technique, puncture site was prepared with izopropyl alcohol solution. Skin was anesthetized with subcutaneous injection of 1% lidocaine. Spinal puncture was achieved using median or paramedian technique with 27G pencil-point spinal needle. After confirmation of free flow of cerebrospinal fluid 15 mg of 0,5% bupivacaine was administered intrathecaly. Block level was assessed by lack of sensation to alcohol swab in periumbilical area and complete motor block (Bromage 3).
Postoperative pain management with acetaminophen
DrugPostoperatively patients received 1,0g of paracetamol every 6 hours,
PCA IV Oxycodone
DeviceAll patients were equipped with PCA capable syringe pump (Perfusor Space, B. Braun) with 40 milligrams of oxycodone. Care provider explained thoroughly how to operate the device and educated about possible adverse effects.
Postoperative pain management with dexketoprofen
DrugPostoperatively patients received 50mg of dexketoprofen intravenously every 8 hours.
Postoperative pain management with metamizole
DrugPostoperatively patients received 1,0g of metamizole intravenously every 6 hours.
Preemptive Analgesics
DrugAfter securing intravenous line each patient received preemptive analgesia with 1,0g paracetamol and 1,0g metamizole.
Patient monitor
DevicePostoperatively each patient's vital signs were monitored continuously using patient monitor for 48 hours.
Analgesic efficacy
Analgesic efficacy defined as mean value of NRS (Numerical Rating Scale) at 4, 8, 12 ,24 and 48 hours postoperatively at rest and during rehabilitation/movement.
Safety profile
Frequency of adverse events including excessive sedation (defined as Richmond Agitation Sedation Score RASS≤-1), constipation, postoperative nausea and vomiting, pruritus and respiratory depression defined as sudden drop in respiration rate by ≥90% for ≥10 seconds or cyanosis.
Patient satisfaction
Patient satisfaction with pain management measured with Likert scale. 1. Very satisfied. 2. Satisfied. 3. Neither satisfied nor dissatisfied. 4. Dissatisfied. 5. Very dissatisfied.
Length of stay
Length of stay postoperatively.
Time to rescue analgesia
Amount of time before first bolus of oxycodone delivered by PCA syringe pump.
Cumulative dose of oxycodone
Cumulative dose of oxycodone over 48 hours postoperatively.
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