Epidural blood patch (EBP) is the injection of autologous blood into the epidural space with the intent of sealing off a dural tear and stopping the leakage of cerebrospinal fluid (CSF). EBP may cause an increase in intracranial pressure (ICP) due to the mass effect of the injected blood volume, causing CSF from the spinal compartment to enter the intracranial compartment. EBP is usually considered in the management of moderate to severe headache (HA) attributed to low CSF pressure, such as post-dural puncture HA (PDPH), CSF fistula HA, and HA attributed to spontaneous intracranial hypotension (SIH) that does not respond to conservative management. However, prophylactic administration of EBP after accidental dural puncture can hardly be substantiated at present. EBP is generally safe but may rarely be associated with serious complications. Therefore, it should be carefully planned and performed under C-arm fluoroscopic guidance. Although many studies on PDPH and SIH have been conducted until recently, only few reviews have summarized the effectiveness of EBP from the perspective of a pain physician. This article reviews the current literature on the indication, contraindication, procedural consideration, post-procedural management, outcomes, and complications of EBP and the considerations for EBP in patients with COVID-19.

Ginseng saponin has long been used as a traditional Asian medicine and is known to be effective in treating various kinds of pain. Ginsenoside Rf is one of the biologically active saponins found in ginseng. We evaluated ginsenoside Rf's antinociceptive and anti-inflammatory effects, and its mechanism of action on adrenergic and serotonergic receptors, in an incisional pain model. Mechanical hyperalgesia was induced via plantar incision in rats followed by intraperitoneal administration of increasing doses of ginsenoside Rf (vehicle, 0.5 mg/kg, 1 mg/kg, 1.5 mg/kg, and 2 mg/kg). The antinociceptive effect was also compared in a Positive Control Group that received a ketorolac (30 mg/kg) injection, and the Naïve Group, which did not undergo incision. To evaluate the mechanism of action, rats were treated with prazosin (1 mg/kg), yohimbine (2 mg/kg), or ketanserin (1 mg/kg) prior to receiving ginsenoside Rf (1.5 mg/kg). The mechanical withdrawal threshold was measured using von Frey filaments at various time points before and after ginsenoside Rf administration. To evaluate the anti-inflammatory effect, serum interleukin (IL)-1β, IL-6, and tumor necrotizing factor-α levels were measured. Ginsenoside Rf increased the mechanical withdrawal threshold significantly, with a curvilinear dose-response curve peaking at 1.5 mg/kg. IL-1β, IL-6, and tumor necrotizing factor-α levels significantly decreased after ginsenoside Rf treatment. Ginsenoside Rf's antinociceptive effect was reduced by yohimbine, but potentiated by prazosin and ketanserin. Intraperitoneal ginsenoside Rf has an antinociceptive effect peaking at a dose of 1.5 mg/kg. Anti-inflammatory effects were also detected.

This study aims to evaluate retrospectively the electronic medical records of surgical patients who received intravenous patient-controlled analgesia, to identify potential relationships between the incidence and risk factors of postoperative nausea and vomiting (PONV). Records of 6773 adult patients who received fentanyl-based intravenous patient-controlled analgesia after surgery at Chung-Ang University Hospital between January 1, 2010 and December 31, 2015 were reviewed. Multiple logistic regressions were used to identify risk factors for PONV. Of 6773 patients, 1216 (18.0%) were recorded to have PONV. In multiple logistic regression analysis, female gender, nonsmoking status, history of motion sickness or PONV, use of desflurane and nitrous oxide, and preintubation use of opioid analgesia were independent risk factors for PONV. Despite the use of antiemetic prophylaxis, 18.0% of patients with intravenous patient-controlled analgesia had PONV. Use of desflurane and nitrous oxide, in addition to risk factors included in the Apfel score (female gender, nonsmoking status, history of PONV or motion sickness, and use of postoperative opioids) were identified as independent risk factors. As the incidence of PONV was 2.8%, 6.0%, 11.7%, 15.2%, 21.1%, 50.0%, and 100% for patients who had 0, 1, 2, 3, 4, 5, and all these risk factors, respectively, risk-adapted, multimodal, or combination therapy should be applied for patients receiving general anesthesia.

Junhyeok Kim, Min Kyoung Kim, Geun Joo Choi, Hwa Yong Shin, Beom Gyu Kim, and Hyun Kang. Korean J Pain 2021;34:509-33. https://doi.org/10.3344/kjp.2021.34.4.509

Postoperative nausea and vomiting (PONV) is one of the most common postsurgical complications. Palonosetron, a 5-hydroxytryptamine receptor antagonist, is effective for PONV prevention. Herein, we compared palonosetron and aprepitant (a neurokinin-1 receptor antagonist) for PONV prevention in patients indicated for laparoscopic gynaecologic surgery. Ninety-three patients who were scheduled to undergo laparoscopic gynaecologic surgery under general anaesthesia were assigned to receive either a single intravenous injection of 0.075-mg palonosetron or 40-mg oral aprepitant in a double-blind randomised trial. The primary efficacy end points included complete response (visual analogue scale [VAS] nausea score <4 and no use of rescue therapy) 0–48 h after surgery. Nausea severity (0–10) and use of rescue therapy were monitored for 0–48 h. The secondary efficacy end points were the effect of aprepitant quantified using a 10-point VAS for pain, consumption of intravenous patient-controlled analgesia, and use of rescue analgesics. Aprepitant was non-inferior to palonosetron in terms of complete response 0–48 hours after surgery (74% vs. 77%). At 0 and 2 h after administration, the nausea severity with 40-mg aprepitant was significantly lesser than that with 0.075-mg palonosetron (P < 0.05). At 6 and 24 h after administration, fentanyl consumption with 40-mg aprepitant was significantly lower than that with 0.075-mg palonosetron. Greater amounts of rescue analgesics were required in the aprepitant group. Palonosetron and aprepitant were both effective for PONV prevention in the patients indicated for laparoscopic gynaecologic surgery. The drugs can be used in combination for multimodal therapy because they bind to different receptors. More research is needed to evaluate the effects of aprepitant on pain management in humans.