Ketamine and tramadol for the prevention of shivering during spinal anaesthesia

The effects of intravenous tramadol vs. intravenous ketamine in the prevention of shivering during spinal anesthesia: A meta-analysis of randomized controlled trials

Background

Shivering is a common complication after subarachnoid administration of local anesthetics. Intravenous ketamine and tramadol are widely available anti-shivering drugs, especially in developing settings. This meta-analysis aimed to compare the effects of intravenous ketamine vs. tramadol for post-spinal anesthesia shivering.

Materials and methods

PubMed/MEDLINE, Web of Science, Cochrane Library, Embase, and Google Scholar databases were used to search for relevant articles for this study. Mean difference (MD) with 95% confidence interval (CI) was used to analyze continuous outcomes, and risk ratio (RR) with 95% CI to analyze categorical results. The heterogeneity of the included studies was assessed using the I2 test. We utilized Review Manager 5.4.1 to perform statistical analysis.

Results

Thirteen studies involving 1,532 patients were included in this meta-analysis. Ketamine had comparable effects in preventing post-spinal anesthetics shivering [RR = 1.06; 95% CI (0.94, 1.20), P = 0.33, I ² = 77], and onset of shivering [MD = -0.10; 95%CI (- 2.68, 2.48), P = 0.94, I ² = 0%], lower incidences of nausea and vomiting [RR = 0.51; 95%CI (0.26, 0.99), P = 0.05, I ² = 67%], and lower incidences of bradycardia [RR = 0.16; 95%CI (0.05, 0.47), P = 0.001, I ² = 33%], higher incidence of hallucinations [RR = 12; 95%CI (1.58, 91.40), P = 0.02, I ² = 0%], and comparable effects regarding the incidences of hypotension [RR = 0.60; 95%CI (0.30, 1.21), P = 0.15, I ² = 54%] as compared to tramadol.

Conclusions

Intravenous ketamine and tramadol are comparable in the prevention of post-spinal anesthetic shivering. Ketamine had a better outcome with less occurrences of nausea, vomiting, and bradycardia. However, ketamine was associated with higher incidences of hallucinations than tramadol.

Comparison of weight-adjusted dose versus fixed dose ondansetron in preventing shivering following spinal anaesthesia for caesarean deliveries

Background

Spinal anaesthesia is an effective regional anaesthesia technique, which is preferred in almost 86% of caesarean sections in the United States and United Kingdom. Eighty percent of caesarean sections done at the Aga Khan University hospital are under spinal anaesthesia. Shivering is a common complication of spinal anaesthesia, it occurs in 40%-64% of patients after neuraxial anaesthesia. Shivering may cause maternal and fetal hypoxemia, maternal discomfort and a problem to the anaesthesiologists when it comes to monitoring the patient during caesarean sections. Ondansetron a 5-HT3 receptor antagonist is effective in treatment and prevention of post-spinal anesthesia shivering. In published studies, use of a fixed dose in patients with different weights, masked the dose effect ondansetron in preventing shivering, such that not adjusting the dose according to the weight of patients' resulted in a higher occurrence of shivering. No study has compared different doses of ondansetron in preventing shivering in parturient women who have had spinal anaesthesia for caesarean section.

Objectives

To determine if a weight-adjusted dose is better than a fixed dose of ondansetron in preventing shivering following spinal anesthesia for caesarean delivery.

Method

This was a randomized, double-blinded controlled trial of 124 women scheduled for elective caesarean surgery. The women were randomized into two equal groups. The intervention group received intravenous ondansetron weight adjusted dosing at 0.1mg/kg and the control group received a fixed dose of 4mg before spinal anesthesia. The occurrence and severity of shivering and other outcomes, such as headache, pruritus were assessed and recorded during the surgery and post-operative period.

Results

A total of 124 patients were included in the study. Social demographic data and baseline vital signs did not differ significantly between the groups. Shivering was observed in 14 patients (22.6%) in the control group that received 4mg ondansetron and 7 patients (11.3%) in the intervention group that had 0.1mg/kg of ondansetron, but there was no statistical difference between the groups (p- value 0.090). The severity of shivering was greater in the control group compared to intervention group where patients who developed grade two shivering were 8.1% to 0% respectively. (P value 0.047). There was no difference in the occurrence of pruritus between the two groups. No patient required treatment for very severe shivering.

Conclusion

This study, found that ondansetron weight adjusted dose at 0.1mg/kg, reduced the severity of shivering when compared to a fixed dose ondansetron at 4mg.

The P1 visual-evoked potential, red light, and transdiagnostic psychiatric symptoms

A reduced P1 visual-evoked potential amplitude has been reported across several psychiatric disorders, including schizophrenia-spectrum, bipolar, and depressive disorders. In addition, a difference in P1 amplitude change to a red background compared to its opponent color, green, has been found in schizophrenia-spectrum samples. The current study examined whether specific psychiatric symptoms that related to these P1 abnormalities in earlier studies would be replicated when using a broad transdiagnostic sample. The final sample consisted of 135 participants: 26 with bipolar disorders, 25 with schizophrenia-spectrum disorders, 19 with unipolar depression, 62 with no current psychiatric disorder, and 3 with disorders in other categories. Low (8%) and high (64%) contrast check arrays were presented on gray, green, and red background conditions during electroencephalogram, while an eye tracker monitored visual fixation on the stimuli. Linear regressions across the entire sample (N = 135) found that greater severity of both clinician-rated and self-reported delusions/magical thinking correlated with a reduced P1 amplitude on the low contrast gray (neutral) background condition. In addition, across the entire sample, higher self-reported constricted affect was associated with a larger decrease in P1 amplitude (averaged across contrast conditions) to the red, compared to green, background. All relationships remained statistically significant after covarying for diagnostic class, suggesting that they are relatively transdiagnostic in nature. These findings indicate that early visual processing abnormalities may be more directly related to specific transdiagnostic symptoms such as delusions and constricted affect rather than specific psychiatric diagnoses or broad symptom factor scales.

Efficacy of intravenous tramadol and low-dose ketamine in the prevention of post-spinal anesthesia shivering following cesarean section: a double-blinded, randomized control trial

Background

Shivering is a frequent and undesirable complication of spinal anesthesia. It is a physiologic response to increase the body core temperature in an attempt to raise metabolic heat production. However, shivering may trigger myocardial ischemia; increase intraocular and intracranial pressures, increase wound pain, delay wound healing and interfere with pulse rate, blood pressure and electrocardiogram monitoring. We aimed to compare the efficacy of intravenous (IV) ketamine with IV tramadol for the prevention of shivering in patients who underwent cesarean delivery under spinal anesthesia.

Patients and methods

A prospective, randomized, double-blind study was conducted. One hundred and twenty-three American Society of Anesthesiologist I and II patients, aged between 18 and 39 years, who underwent cesarean section were included in the study. Patients were randomly allocated to one of three groups: group S (n=41; control group) received saline, group K (n=41) received ketamine 0.2 mg/kg and group T (n=41) received tramadol 0.5 mg/kg. Incidence and grade of shivering and side effects between the treatment groups were recorded.

Results

The incidence of shivering was significantly reduced in the ketamine and tramadol groups (41.5% and 53.7%, respectively) compared to the saline group (70.7%; p=0.028). Grade 3 shivering occurred in 16 (39%) patients in the saline group, compared to 9 (22%) in the tramadol group and 8 (19.5%) in the ketamine group (p=0.011). Only two cases in the saline group developed grade 4 shivering (p<0.01). Neonatal outcome and perioperative complications were comparable among the three groups.

Conclusion

The prophylactic administration of low-dose IV ketamine or IV tramadol is effective for reducing the incidence and intensity of shivering. We recommend low-dose IV ketamine or tramadol prophylaxis for parturients undergoing cesarean section under spinal anesthesia.

Evaluation of the effects of ketamine on spinal anesthesia with levobupivacaine or ropivacaine

Spinal anesthesia or regional anesthesia is a potent anesthetic procedure. Additional modalities have been sought to increase the duration of block in spinal anesthesia. Ketamine is an N-methyl-D-aspartate (NMDA) receptor blocker that has an anesthetic effect when injected intrathecally and has a synergic effect with bupivacaine. Ketamine also has potent analgesic properties. The present study investigated the effect of intrathecally administered ketamine on spinal anesthesia with levobupivacaine or ropivacaine. Sprague-Dawley rats at post-natal day 21 were exposed to spinal anesthesia with 0.5% levobupivacaine or 0.5% ropivacaine. Separate groups of rats were treated with intrathecal ketamine at a 5 or 10 mg/kg bodyweight dose along with ropivacaine or levobupivacaine. The thermal and mechanical withdrawal latencies of the animals were determined using hot plate and von Frey filaments, respectively. A rotarod apparatus was employed to assess the capacity of the rats to rotate the spindle at 24 h following anesthesia. The gait of the rat pups was also assessed. Intrathecal administration of ketamine resulted in dense blocks and extended the duration of spinal blocks as evidenced by thermal latencies and responses to von Frey filaments. The latency to fall was shorter in rats exposed to ketamine along with ropivacaine or levobupivacaine spinal anesthesia. The gait parameters were also more disturbed upon ketamine administration. In conclusion, ketamine administration with ropivacaine or levobupivacaine increased the intensity and duration of spinal blockade, thereby increasing the anesthetic effects.