The Effect of Intravenous Ketamine After Spinal Anesthesia on the Duration of Postoperative Analgesia and Analgesic Requirement

Objective: To evaluate the impact of ketamine following spinal anesthesia on the duration of postoperative analgesia and the need for analgesics. Methods: This was a prospective, randomized, double-blinded placebo-controlled study done over a period of two years. A total of 60 participants undergoing elective surgeries under spinal anesthesia were randomized into two groups. After 10 min of spinal anesthesia and achieving the required level of sensory and motor blockade, both groups were given Inj. Midazolam 1 mg intravenously, followed by Inj. Ketamine 0.25 mg/kg, volume made up to 10 mL with normal saline, given intravenously for Group K and Inj. Normal Saline 10 mL was given intravenously for Group N. Hemodynamic monitoring was done intraoperatively, and the postoperative visual analog score (VAS), sedation score, the mean time for the first rescue analgesia, and the total dose of postoperative analgesic required in 24 h were tabulated. Results: There was no statistical difference between the two groups in terms of age, weight, ASA grade, and duration of surgery. In Group K, the VAS scores were significantly lower and patients were comfortable when compared to Group N (P value <.01). The mean time to first rescue analgesia was longer in Group K (6.4 ± 1.69 h) when compared to Group N (2.9 ± 1.01 h), and the total dose of postoperative analgesia (Tramadol) required in 24 h was also significantly less in Group K (143.33 ± 56.83 mg) when compared to Group N (236 ± 49.01 mg). Changes in hemodynamic parameters (heart rate and mean arterial pressure (MAP)) were statistically and clinically not significant in both the intraoperative and postoperative periods between the groups. Conclusion: Patients in Group K were more comfortable, had a longer duration of postoperative analgesia, and required less dose of rescue analgesia in the postoperative period. Ketamine is a safe drug that is readily available, and it decreases the use of opioids and opioid-related side effects. Therefore, ketamine can serve effectively as an adjunctive analgesic drug.

To evaluate analgesic efficacy of dexamethasone as an adjuvant to ropivacaine in pectoral nerve block: A prospective randomized control study.

Background: Pectoral nerve (Pecs) block is an effective component of multimodal analgesic regimens for breast surgeries. In present study we compared analgesic effect of dexamethasone 8 mg as an adjuvant to 0.25% ropivacaine versus 0.25% ropivacaine alone in pectoral nerve block. Methods: The study was conducted in a randomized manner on 60 female patients of American Society of Anesthesiologists (ASA) Grade I and II, aged between 18 to 65 years, scheduled to undergo modified radical mastectomy under general anesthesia (GA). The patients were randomly allocated into 2 groups of 30 patients each. Group A received ultrasound (US)-guided Pecs block with 30 ml of 0.25% ropivacaine and 10 ml normal saline (total volume 40 ml) and Group B received with 30 ml of 0.25% ropivacaine and 8 mg dexamethasone in and 10 ml normal saline (total volume 40 ml). Post-operatively visual analogue score (VAS), duration of analgesia and total analgesic consumption was noted. Student t-test, Mann Whitney U test and Chi-square test were used for statistical analysis. Results: VAS were persistently low for first 4 hours in group B and for first 9 hours in group A (p value < 0.001 at some intervals). The mean duration of analgesia was prolonged in group B as compared to group A (612.33 ± 41.77 min in Group B and 307.70 ± 22.37min in group A) (p <0.001). Total analgesic consumption in first 24 hours post-operatively was also statistically lower in Group B (97.50± 34.96 mg) as compared to group A (177.50± 36.76) (p<0.001). No patient under study reported any adverse effects. Conclusion: Addition of 8 mg dexamethasone as adjuvant to 0.25% ropivacaine for pectoral nerve block increases the duration of analgesia and significantly reduces the amount of analgesic requirement in first 24 hours postoperatively without any significant adverse effects.

The Effects of Intraoperative Adenosine Infusion on Acute Opioid Tolerance and Opioid Induced Hyperalgesia Induced by Remifentanil in Adult Patients Undergoing Tonsillectomy

BACKGROUND: Adenosine has been shown to have a wide spectrum of unique pain-relieving effects in various clinical situations. The aim of this study was to investigate the effects of intraoperative adenosine infusion on acute opioid tolerance and opioid induced hyperalgesia induced by remifentanil in adult patients undergoing tonsillectomy. METHODS: For this study, ninety patients were randomly allocated into groups that receive either adenosine (adenosine group) or saline (remifentnail group) intravenously under remifentanil based anesthesia and saline (sevoflurane group) under sevoflurane anesthesia. The patients in adenosine group received adenosine at dose of 80 microg/kg/min, and those in remifentnail group and sevoflurane group received an equal volume of saline 10 minutes after the induction of anesthesia until the end of surgery. Intraoperative evaluation included time weighted mean remifentanil dose, and postoperative evaluations included degree of pain severity at 1, 6, 12, and 24 hours, time to first postoperative requirement, and analgesic dose required during 24 hours after operation. RESULTS: Time weighted mean remifentanil dose during intraoperative period in adenosine group was significantly lower than that of remifentnail group (P = 0.00). The first postoperative analgesic were required earlier in remifentanil group than sevoflurane group or adenosine group (P = 0.00). Pethidine requirement during 24 hours in sevoflurane group and adenosine group was significantly lower than that of remifentnail group (P = 0.00). The visual analog scale scores for pain in sevoflurane group and adenosine group were significantly lower than those of remifentnail group for 12 hours after operation (P = 0.00). Incidence of hypotension (P = 0.024) and number of ephedrine administered (P = 0.011) in adenosine group were significantly higher than those of sevoflurane group. CONCLUSIONS: The above results suggest that intraoperative adenosine infusion prevent acute opioid tolerance and opioid induced hyperalgesia induced by remifentanil.

The Effects of Intraoperative Adenosine Infusion on Acute Opioid Tolerance and Opioid Induced Hyperalgesia Induced by Remifentanil in Adult Patients Undergoing Tonsillectomy

BACKGROUND: Adenosine has been shown to have a wide spectrum of unique pain-relieving effects in various clinical situations. The aim of this study was to investigate the effects of intraoperative adenosine infusion on acute opioid tolerance and opioid induced hyperalgesia induced by remifentanil in adult patients undergoing tonsillectomy. METHODS: For this study, ninety patients were randomly allocated into groups that receive either adenosine (adenosine group) or saline (remifentnail group) intravenously under remifentanil based anesthesia and saline (sevoflurane group) under sevoflurane anesthesia. The patients in adenosine group received adenosine at dose of 80 microg/kg/min, and those in remifentnail group and sevoflurane group received an equal volume of saline 10 minutes after the induction of anesthesia until the end of surgery. Intraoperative evaluation included time weighted mean remifentanil dose, and postoperative evaluations included degree of pain severity at 1, 6, 12, and 24 hours, time to first postoperative requirement, and analgesic dose required during 24 hours after operation. RESULTS: Time weighted mean remifentanil dose during intraoperative period in adenosine group was significantly lower than that of remifentnail group (P = 0.00). The first postoperative analgesic were required earlier in remifentanil group than sevoflurane group or adenosine group (P = 0.00). Pethidine requirement during 24 hours in sevoflurane group and adenosine group was significantly lower than that of remifentnail group (P = 0.00). The visual analog scale scores for pain in sevoflurane group and adenosine group were significantly lower than those of remifentnail group for 12 hours after operation (P = 0.00). Incidence of hypotension (P = 0.024) and number of ephedrine administered (P = 0.011) in adenosine group were significantly higher than those of sevoflurane group. CONCLUSIONS: The above results suggest that intraoperative adenosine infusion prevent acute opioid tolerance and opioid induced hyperalgesia induced by remifentanil.