The Effect of a Single Dose Dexamethasone on Postoperative Pain in Patients Undergoing Gynecological Laparotomy Surgery.

Background: Acute postoperative pain is associated with many undesirable outcomes. Opioids are the mainstay for pain relief but their common side effects are still problematic. Many adjunctive agents such as NSAIDs and gabapentin have already been proved to be effective as multimodal analgesia. Dexamethasone has been reported to reduce postoperative nausea and vomiting but the analgesic effect is not well defined especially in open abdominal surgery. Objective: To evaluate efficacy of a single perioperative dose of dexamethasone on postoperative pain in gynecological laparotomy surgery. Material and Method: A prospective, randomized, double-blinded study was approved by the Institutional Review Board and registered with the Thai Clinical Trials Registry as TCTR20151116001. Fifty-two patients scheduled for elective gynecological laparotomy surgery were enrolled in the present study. Patients were randomized into two groups based on computer generated random number list. After induction, group D received intravenous dexamethasone 8 mg and group P received saline. Both groups were anesthetized in a standardized manner. Postoperative pain was managed with intravenous morphine using patient controlled analgesia. The primary outcome was total morphine consumption evaluated at 6- and 24-hour postoperatively. Pain score, nausea, and vomiting, shivering, sore throat, and adverse effects of dexamethasone were also recorded. Results: The total dose of morphine (0 to 24 hour after surgery) was less in D group (15.88±9.59 mg) compared with P group (24.25±15.26 mg) (p = 0.027). The doses during hour 0 to 6 were smaller in D group (11.28±6.66 mg) than the placebo (15.79±12.50) (p = 0.435). The numerical rating scale for pain at rest did not differ in both study groups, but pain in motion was less in D group than P group at 6-hour (p = 0.03) and 24-hour (p = 0.039) after surgery. No adverse effect was observed in both groups. Conclusion: A single perioperative dose 8 mg of dexamethasone is safe and significantly reduces pain at movement and morphine consumption in 24 hours after gynecological laparotomy surgery.

Analgesic Efficacy of Intravenous Dexamethasone as an Adjunct to Ultrasound-Guided Paravertebral Block with Bupivacaine in Video-Assisted Thoracoscopic Surgery.

Purpose: Thoracic paravertebral block (TPVB) is a recommended regional analgesia during video-assisted thoracoscopic surgery (VATS). However, single-injection TPVB does not last long enough to provide sufficient acute postoperative pain relief. Continuous TPVB through a catheter is technically challenging and often unreliable. Intravenous dexamethasone extends the analgesic duration with some peripheral nerve blocks. However, data on the effect of intravenous dexamethasone on pain relief with TPVB are limited. This study aimed to assess the analgesic efficacy of intravenous dexamethasone in patients who received TPVB for VATS. Patients and Methods: In this multicenter prospective randomized controlled trial, we recruited patients aged between 18 and 80 years with the American Society of Anesthesiologists of physical status class 1-3 and underwent elective VATS. Patients under general anesthesia randomly received 8 mg of intravenous dexamethasone (group D) or normal saline (group C). Ultrasound-guided TPVB (USG-TPVB) was performed at the T4-T5 and T6-T7 spaces. Multimodal analgesia was achieved via paracetamol, tramadol and intravenous morphine for both study groups. The primary outcome was time for the first analgesic requirement. Postoperative pain in terms of numeric rating score (NRS), total morphine consumption and postoperative nausea and vomiting (PONV) were assessed. Results: After excluding one patient, 59 patients were analyzed. There were no intergroup differences in baseline characteristics. The time to first analgesic requirement was longer in group D (305 [240, 510] minutes) than in group C (270 [180, 300] minutes) (P value = 0.02). The NRS at rest and on movement was lower in group D than in group C at 12 hours but did not differ at other time points. Postoperative morphine consumption was significantly lower in group D than in group C at 6,12,24 and 48 hours. Incidences of PONV were comparable between the groups. Conclusion: Intravenous dexamethasone, used as an adjunct to a single-injection USG-TPVB prolonged analgesic duration, had an opioid-sparing effect and provided better postoperative pain relief after VATS.

Distribution of injectate administered through a catheter inserted by three different approaches to ultrasound-guided thoracic paravertebral block: a prospective observational study.

BACKGROUND: Despite the popularity of continuous thoracic paravertebral block (TPVB), there is a paucity of information on catheter tip position and distribution of injectate through the catheter. We observed, in real time, the spread of dye, the catheter tip position and sensory block levels produced with three different (intercostal (IC), transverse process sagittal (TS) and paralaminar (PL)) approaches to ultrasound-guided TPVB in patients undergoing video-assisted thoracoscopic surgery. METHODS: After the induction of general anesthesia, ultrasound-guided TPVB was conducted with a patient in the lateral decubitus position. During surgery, 10 mL of dye was injected through a catheter to observe the catheter tip and the dye distribution under thoracoscopy. Dermatomal sensory block levels were measured postoperatively. RESULTS: Ten patients for each of three different approaches completed the study. There were a variety of dye spreading patterns. The median (range) number of segmental levels stained with dye was 1.5 (1-4), 3 (1-4) and 3 (1-5) with the IC, TS and PL approaches, respectively. We observed that a catheter tip was present at the same segmental paravertebral space as intended in 50%-90% of patients using these approaches. The median (range) number of dermatomes with sensory blockade at 6 hours after block was 2.5 (1-4), 3 (2-8) and 3 (1-8) with the IC, TS and PL approaches, respectively. CONCLUSIONS: Although a bolus injection through a catheter for ultrasound-guided TPVB produced multiple levels of spread and sensory blockade in more than half the patients, considerable differences existed in the spread regardless of approach.