Comparison of peritonsillar infiltration effects of ketamine and tramadol on post tonsillectomy pain: a double-blinded randomized placebo-controlled clinical trial

Aim

To assess the effect of peritonsillar infiltration of ketamine and tramadol on post tonsillectomy pain and compare the side effects.

Methods

The double-blind randomized clinical trial was performed on 126 patients aged 5-12 years who had been scheduled for elective tonsillectomy. The patients were randomly divided into 3 groups to receive either ketamine, tramadol, or placebo. They had American Society of Anesthesiologists physical status class I and II. All patients underwent the same method of anesthesia and surgical procedure. The three groups did not differ according to their age, sex, and duration of anesthesia and surgery. Post operative pain was evaluated using CHEOPS score. Other parameters such as the time to the first request for analgesic, hemodynamic elements, sedation score, nausea, vomiting, and hallucination were also assessed during 12 hours after surgery.

Results

Tramadol group had significantly lower pain scores (P?=?0.005), significantly longer time to the first request for analgesic (P?=?0.001), significantly shorter time to the beginning of liquid regimen (P?=?0.001), and lower hemodynamic parameters such as blood pressure (P?=?0.001) and heart rate (P?=?0.001) than other two groups. Ketamine group had significantly greater presence of hallucinations and negative behavior than tramadol and placebo groups. The groups did not differ significantly in the presence of nausea and vomiting.

Conclusion

Preoperative peritonsillar infiltration of tramadol can decrease post-tonsillectomy pain, analgesic consumption, and the time to recovery without significant side effects.Registration No: IRCT201103255764N2Postoperative pain has not only a pathophysiologic impact but also affects the quality of patients’ lives. Improved pain management might therefore speed up recovery and rehabilitation and consequently decrease the time of hospitalization (1). Surgery causes tissue damage and subsequent release of biochemical agents such as prostaglandins and histamine. These agents can then stimulate nociceptors, which will send the pain message to the central nervous system to generate the sensation of pain (2-4). Neuroendocrine responses to pain can also cause hypercoagulation state and immune suppression, leading to hypoglycemia, which can delay wound healing (5).Tonsillectomy is a common surgery in children and post-tonsillectomy pain is an important concern. Duration and severity of pain depend on the surgical technique, antibiotic and corticosteroid use, preemptive and postoperative pain management, and patient’s perception of pain (6-9). There are many studies that investigated the control of post tonsillectomy pain using different drugs such as intravenous opioids, non-steroidal anti-inflammatory drugs, steroids, ketamine, as well as peritonsillar injection of local anesthetic, opioid, and ketamine (6,7,10-14).Ketamine is an intravenous anesthetic from phencyclidin family, which because of its antagonist effects on N methyl-D-aspartate receptors (that are involved in central pain sensitization) has regulatory influence on central sensitization and opium resistance. It can also band with mu receptors in the spinal cord and brain and cause analgesia. Ketamine can be utilized intravenously, intramuscularly, epidurally, rectally, and nasaly (15,16). Several studies have shown the effects of sub-analgesic doses of ketamine on postoperative pain and opioid consumption (7,13,15-17). Its side effects are hallucination, delirium, agitation, nausea, vomiting, airways hyper-secretion, and increased intra cerebral pressure and intra ocular pressure (10,11,15,16).Tramadol is an opium agonist that mostly effects mu receptors, and in smaller extent kappa and sigma receptors, and like anti depressant drugs can inhibit serotonin and norepinephrine reuptake and cause analgesia (6,12,18). Its potency is 5 times lower than morphine (6,12), but it has lower risk of dependency and respiratory depression, without any reported serious toxicity (6,12). However, it has some side effects such as nausea, vomiting, dizziness, sweating, anaphylactic reactions, and increased intra-cerebral pressure. It can also lower the seizure threshold (6,12,18,19).Several studies have confirmed the efficacy of tramadol and ketamine on post-tonsillectomy pain (6,10-12,20). In previous studies, effects of peritonsillar/ IV or IM infiltration of tramadol and ketamine were compared to each other and to placebo, and ketamine and tramadol were suggested as appropriate drugs for pain management (6,7,10-19,21). Therefore, in this study we directly compared the effect of peritonsillar infiltration of either tramadol or ketamine with each other and with placebo.