INTRODUCTION:
Surgery produces both visceral and somatic pain. This results in the release of nociceptive substances such as prostaglandins, histamine, serotonin, bradykinnin, 5-hydroxytryptamine, substance P and generation of noxious stimuli that are transduced by nociceptors and
transmitted by A delta and C nerve fibres to the neuraxis.
Pain is the most important factor responsible for ineffective ventilation, ineffective cough, and impaired ability to sigh and breathe deeply, in patients after upper abdominal surgery. This may contribute to pulmonary atelectasis leading to ventilation/perfusion abnormalities
and hypoxemia, as well as infection, after surgery.
Many of these adverse effects can be eliminated or reduced by adequate post operative pain relief. Several methods have been advocated to reduce postoperative pain.
The administration of local anesthetics into the pleural space is a technique of providing analgesia of rapid onset and long duration. This analgesia is accomplished without causing the respiratory depression or sedation associated with the use of opioids. This study is chosen to investigate the efficacy of interpleural analgesia in treating postoperative pain.
AIM OF THE STUDY:
This study intends to prospectively analyze the efficacy of
interpleural analgesia in reducing post operative pain and parenteral analgesic requirement in patients undergoing upper abdominal surgery.
PATIENTS AND METHODS:
After approval from local ethics committee and written informed consent 36 patients undergoing elective upper abdominal surgeries like open cholecystectomy, nephrectomy , pyelolithotomy and pyeloplasty at Government General Hospital, Chennai were enrolled in the study. The
inclusion criteria were age 19 to 65 years ASA physical status 1 & 2 with no contraindications for the technique and drugs. These include pleural injury, pleural adhesion, fibrosis or effusion, COPD, local infection, bleeding diathesis and allergy to study drugs. The linear
visual analog scales (VAS) were explained to the patients prior to the study.
Patients were premedicated with Inj glycopyrrolate 0.2mg and Inj fentanyl 100 micrograms IV just before induction. Patients were induced with Inj propofol 2mg /Kg, Inj Suxamethonium 100mg IV and intubated one minute later with appropriate size endotracheal tube orally. The
anaesthesia was maintained with nitrous oxide – oxygen mixture 3:2, muscle relaxant Inj Vecuronium and volatile agents.
When the surgery was over the patients were randomly assigned to two trearment groups of 18 patients in each.
1. Pleural analgesia (bupivacaine) combined with Parenteral analgesics (Pentazocine).
2. Parenteral analgesics alone. (Pentazocine).
Statistical Analysis:
Student t test was used to compare the pentazocine requirement and VAS scores between the pleural and control groups. Data was analyzed with SPSS software. Data are presented as means ± SD. The P values were provided to indicate statistical significance. P < 0.05 was considered as significant.
RESULTS:
One patient was excluded from the study due to aspiration of blood in the pleural catheter. Demographic data were similar in both the groups (Table 1). Mean age was 40.7yrs ± 11.30 (21 to 56 yrs) in pleural group and 44.6 yrs ± 11.9 (18 to 65 yrs) in control group. No episodes of hypotension or bradycardia were noted. Neither pneumothorax nor CNS
(central nervous system) toxic reactions (tremor, perioral numbness, muscle twitches, metallic taste, tinnitus, convulsions) were noted. The catheter insertion using loss of resistance technique described above was easy to identify the pleural space and effective.
CONCLUSION:
It is concluded from this study that intermittent interpleural analgesia with bupivacaine was more effective than intermittent parenteral administration of pentazocine alone, in reducing the severity of pain after upper abdominal surgery up to 48 hours postoperatively and
can be recommended for sufficient pain control
