Comparative Study of the Effect of Intravenous Paracetamol and Tramadol in Relieving of Postoperative Pain after General Anesthesia in Nephrectomy Patients.

AIM: The aim of this study was to compare the effect of intravenous paracetamol and tramadol in relieving of postoperative pain after general anesthesia for nephrectomy in prospective donor patients for kidney transplantation.
MATERIALS AND METHODS: A randomized study was conducted on 100 adult patients scheduled for nephrectomy aged from 35 to 55 years of both sexes and divided into two groups and were administered intravenous paracetamol and tramadol for postoperative pain relief and assessed with visual analog scale score and variations in vital parameters to assess extent of pain relief.
RESULTS: After statistical interpretation of collected data, the observations were extrapolated. There was a statistically significant difference in the pain intensity scores obtained between the paracetamol and tramadol groups.
CONCLUSION: On the basis of the present study, it is concluded that tramadol due to its lesser onset of action time was superior to paracetamol in providing acute postoperative pain relief.

RCT Entities:   Population Interventions Outcomes

INTRODUCTION

The International Association for the Study of Pain has defined pain as an unpleasant sensory and emotional experience associated with actual or potential tissue damage or describe in terms of such damage.

Sherrington in 1906 defined pain as “the physical adjunct to an imperative protective reflex.”

The incidence of postoperative pain varies individually and is related to site and type of surgery.

A major physical trauma is being faced by the kidney donors in view of postoperative pain and discomfort in the convalescence period.[123456]

The opioids and nonsteroidal anti-inflammatory drugs (NSAIDS) that are being used for decades have many side effects such as postoperative nausea and vomiting, respiratory depression, sedation, and renal injury.[7]

The intravenous paracetamol is a nonopioid analgesic which is well tolerated and acts on central nervous system by way of central cyclooxygenase inhibition.[8]

After the approval of intravenous paracetamol (acetaminophen) in 2010, it has been widely used for fever and pain in children and adults.

Like many NSAIDS, it does not interfere with platelet or kidney function.[9]

Tramadol is a synthetic opioid belonging to the aminocyclohexanol group and has weak opioid against properties and central analgesic action.[10]

As both of the drugs have minimal effects on kidneys, this prospective, randomized double-blinded study was done to compare intravenous paracetamol with tramadol in live donor nephrectomies for kidney transplantation.

Our aim to assess statistically for difference in visual analog scale (VAS) score and vital parameters which reflect the pain relief in the postoperative period in the two groups of patients receiving tramadol and paracetamol.

MATERIALS AND METHODS

After approval from the Institutional Ethics Committee and written informed consent from the patient, a randomized study was conducted on 100 adult patients of American Society of Anesthesiologists class I and II planned for nephrectomy in prospective donor patients posted for kidney transplantation.

Exclusion criteria

Patients with severe or moderate hemodynamic disturbances with significant renal, hepatic, respiratory diseases, pregnant and lactating women, and patients already suffering with severe pain and using analgesics were excluded from the study.

All the patients irrespective of group to which they belong received tablet alprazolam 0.25 mg on night before the day of surgery.

Before the surgery, patients were explained about the VAS 0–100 of pain, and the pain relief scores. Pulse rate (PR), arterial blood pressure (noninvasive blood pressure), and respiratory rate (RR) were recorded. Patient's age, weight, height, and preoperative investigations were also noted along with vital data.

The patients were randomly divided into two groups of fifty each and administered with the study drugs intravenously in a double-blind fashion 30 min completion of surgery.

Group I – Received i.v. tramadol 2 mg/kg slow i.v.

Group II – Received i.v. paracetamol 1 g in 100 ml vital infused over 15 min

The dose is repeated 6th hourly. The maximum total dose of tramadol was 400 mg/day, and paracetamol was 4 g/day

Anesthetic protocol was similar for all patients

Postoperative hemodynamic parameters and pain score using VAS score were evaluated

Pain intensity was measured based on VAS pain grading that included scores: 0 (no pains), 10 (worse pain)

VAS was obtained at 0 min, 15 min, 30 min, 1 h, 3 h, 6 h, 12 h, and 24 h

Postoperative hemodynamic parameters such as HR, systolic blood pressure (SBP), RR, oxygen, and saturation (SpO2) percentage were evaluated at regular intervals at 0 min, 15 min, 30 min, 1 h, 3 h, 6 h, 12 h, and 24 h.

OBSERVATION AND RESULTS

Statistical analysis (Chi-square test) was applied to all of the parameters included in the study.

The cases were studied under the following demographic data shown in Table 1, the patients in the two groups were comparable with respect to the age and weight.

Table 1

Demographic data (mean±standard deviation)

There was statistically significant difference in the pain intensity and pain relief scores obtained between tramadol and paracetamol group [Tables 2 and 3].

Table 2

Postoperative pain intensity in visual analog scale (mean±standard deviation)

Table 3

Postoperative pain relief scores (mean±standard deviation)

The basal pain scores are similar in both the groups. The onset of analgesia was faster in tramadol group than paracetamol group. In tramadol group, significant decrease pain intensity scores were observed from 15 min onward (P > 0.05) and from 30 min in paracetamol group. The maximum pain relief was observed at 1 h in tramadol group and 3 h in paracetamol group. This statistically significant difference between the two groups was observed up to 24 h (P > 0.05).

The postoperative sedation scores were also compared by Chi-square test [Table 4], and there was a statistically significant difference in sedation scores up to 6 h (P < 0.05).

Table 4

Sedation scores

When the vital parameters were compared between the two groups, there was no statistically significant difference of PR, SBP, RR, and SpO2 between the two groups at all the time intervals (P > 0.05) [Tables 5–8].

Table 5

Postoperative pulse rate (mean±standard deviation)

Table 8

Postoperative oxygen saturation percentage (mean±standard deviation)

The adverse effects in the 24 h period postoperatively, namely, nausea, vomiting, and retention of urine were noted in the two groups [Table 9]. The incidence of nausea, vomiting, and retention of urine is more in the tramadol group.

Table 9

Postoperative complications

DISCUSSION

The relief of postoperative pain is a subject which has been receiving an increasing amount of attention in the past few years. Despite recent advances in the understanding of postoperative pain and widespread recognition of the problem, clinical surveys indicate that routine treatment of postoperative pain remains unsatisfactory.

A comprehensive management of postoperative pain results in successful recovery.[11] Various methods and agents used for postoperative analgesia are NSAIDS, ketamine, opioids, PCM, peripheral local anesthetics, and epidural analgesia.[12] PCM belongs to class of drugs known as aniline analgesics.[13] It has both central and peripheral actions. The central action is the inhibition of cyclooxygenase enzyme, and peripheral action is by its metabolite N-acetyl P-benzoquinone imine which acts on transient receptor potential ankyrin receptors in the spinal cord to alleviate pain.[1415]

In our study, we compared i.v. paracetamol and tramadol for postoperative pain relief in nephrectomy patients.

Both groups (paracetamol and tramadol) were found comparable on the basis of age, weight, preoperative investigations, and preoperative hemodynamic parameters.

Postoperative pain relief was measured by VAS score and pain relief scores at 0 min, 15, 30, 60, 3, 6, 12, and 24 h taking value at the immediate postoperative period (0 min) as baseline.

Postoperatively, all patients were monitored with SpO2, PR, BP, and RR for 24 h, and these values were compared to that of baseline values which were recorded is immediate postoperative period (0 min).

The parameters observed were compared statistically and Chi-square test was performed where and when appropriate significance was considered when P < 0.05.

The onset of analgesia is faster in tramadol group. There was a significant decrease in VAS score from 15 min onward, and this was observed up to 3 h.

In paracetamol group, the onset of analgesia was slightly delayed. Pain scores significantly decreased after 60 min, and this was observed up to 6 h and pain scores increased thereafter.

In our study, there were no significant changes in postoperative mean SBP and diastolic blood pressures, PR, RR, and percentage SpO2.

Drowsiness was found to be higher in tramadol group and regarding other side effects in tramadol group, the incidence of nausea was 16% and vomiting in 16% of cases.

CONCLUSION

Postoperative analgesia is the key factor of successful recovery from any surgery. From the different parameters compared in our study, both tramadol and paracetamol offer adequate postoperative analgesia. Tramadol due to its quick onset of action and fewer side effects is better than intravenous paracetamol for postoperative analgesia.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

Table 6

Postoperative systolic blood pressure in mmHg (mean±standard deviation)

Table 7

Postoperative respiratory rate per minute (mean±standard deviation)