COMPARISON OF THE EFFECTS OF INTRAVENOUS DICLOFENAC AND PARACETAMOL ON POSTOPERATIVE MORPHINE CONSUMPTION AFTER ORTHOPAEDIC SURGERY

COMPARISON OF THE EFFECTS OF INTRAVENOUS DICLOFENAC AND PARACETAMOL ON POSTOPERATIVE MORPHINE CONSUMPTION AFTER ORTHOPAEDIC SURGERY

Abstract

Moderate to severe postoperative pain is common following orthopaedic surgery and
its treatment is often poor or inadequate. Systemic opioids are regarded as the gold standard
in the relief of moderate to severe postoperative pains. However, morphine administration
after surgery carries a significant risk of side effects such as nausea, vomiting, sedation,
respiratory depression, pruritus and urinary retention.
The combination of morphine with other analgesics such as Non Steroidal Anti
Inflammatory Drugs (NSAIDs) have been found to be effective for postoperative pain
management, reducing morphine consumption and limiting side effects, thereby hastening
recovery1-3.
This research work is a prospective randomized double blind experimental study that
sets out to compare the efficacy of intravenous diclofenac with intravenous (i.v.)
paracetamol in reducing postoperative morphine use thereby reducing morphine side effect
such as nausea, vomiting, sedation, respiratory depression, pruritus and urinary retention
after orthopaedic procedures. After approval by the Institutional Review Committee (IRC)
and consent obtained from each patient, sixty (60) consecutive patients, of ASA physical
status classes I and II aged 18 – 65 years scheduled for orthopaedic procedure were
randomized into two groups. Group A (30) received intravenous paracetamol 15 mg/kg
diluted to 20 mls with normal saline and Group B (n = 30) received intravenous Diclofenac
(1 mg/kg) diluted to 20 mls with normal saline at the beginning of the skin closure. These
study drugs were repeated 8 hours postoperatively.
The patients were premedicated with oral diazepam 10 mg night before surgery and
a repeat dose was given at 6 am on the day of surgery. Antiemetic premedicants were
omitted because the patients were fasted elective cases undergoing peripheral surgery with
reduced risk of postoperative nausea and vomiting. Also as postoperative nausea and
vomiting is one of the common side effects of morphine administration in the
perioperative period, the incidence of this side effect would be better assessed without
premedication with an antiemetic. Balanced general anaesthesia technique with endotracheal
intubation was used in both groups. Minimum basic monitoring [Non-Invasive Blood
Pressure(NIBP), Electrocardiography(ECG), Arterial Oxygen Saturation(Sa02), and End
Tidal Carbondioxide(EtC02)] as recommended by the Royal College of Anaesthetist was
employed. After preoxygenation for three minutes, at induction of anaesthesia i.v Atropine
0.6 mg or i.v. Glycopyrrolate 0.2 mg was given as indicated.
Anaesthesia was induced with sodium thiopentone 5 mg/kg body weight. Possibility
of ventilation by mask was tested and tracheal intubation was facilitated with 0.1 mg/kg
pancuronium bromide. Suxamethonium was not used to facilitate tracheal intubation
because patients are elective cases and suxamethonium is associated with muscle pain.
Correct tube placement was confirmed and IPPV was administered via the Drager (Fabius)
anaesthetic machine. Anaesthesia was maintained with halothane 0.75 – 1% in oxygen,
using a Closed Circuit System with Fresh Gas Flow of 3 litres/min. Intraoperative analgesia
was achieved with intravenous morphine 0.1 mg/kg. Maintenance fluid was administered
and blood was transfused when necessary.
At the beginning of skin closure the study drug intravenous paracetamol 15 mg/kg
maximum of 600 mg (Drugamol) manufactured by the Drugfield Pharmaceutical Company,
Sango Otta with NAFDAC Registration Number 04-6833 diluted to 20 ml with normal
saline was given to group A, a repeat dose was given 8 hours later on the ward. Patients in
group B received the drug Diclofenac sodium 1 mg/kg manufactured by Rotex Media,
Bunsentrasse 4-22946 Trittau/Germany in 20 mls of normal saline and a repeat dose given
8 hours later on the ward.
At the end of the surgery, residual effect of the muscle relaxant was reversed with
atropine 1.2 mg and neostigmine 2.5 mg. Following recovery of consciousness and muscle
power, the patients were extubated and transferred to the recovery room with
monitoring and oxygen administered by facemask at 3 L/min.
In the recovery room, the patient’s vital signs were monitored and assessment of
pain intensity using the Numerical Rating Scale (NRS). Time of first request for analgesia
was noted. Intravenous morphine 2 mg was titrated to effect by the investigator. The
Ramsay sedation score was also monitored. Morphine side effects, adequacy of analgesia
and patient’s satisfaction were documented over the 12 hours study period.
The groups were comparable with respect to demographic characteristics, duration
of surgery and doses of morphine used intraoperatively. The mean time of first analgesic
request was prolonged significantly in Diclofenac group (Group B) 273 ± 304.1 minutes
compared with 119.2 ± 213.3 minutes in paracetamol group (Group A) ( p = 0.014).
There was also a significant difference in morphine consumption postoperatively
over the 12 hours of study Group A 4.6 ± 2.5 compared with Group B 2.4 ± 2.0 (p = 0.001).
No patient in both Groups showed respiratory depression, nausea and vomiting or high
sedation score. Overall pain relief satisfaction over the 12 hours of study was more with the
diclofenac group than in the paracetamol group.
In conclusion, it was found from this research study that intravenous diclofenac 1
mg/kg given towards the end of major orthopaedic surgery significantly improved analgesia.
There was also a reduction in morphine consumption with no untoward side effects and
better patient satisfaction was observed compared with paracetamol.

COMPARISON OF THE EFFECTS OF INTRAVENOUS DICLOFENAC AND PARACETAMOL ON POSTOPERATIVE MORPHINE CONSUMPTION AFTER ORTHOPAEDIC SURGERY

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