Boo Hwi Hong

Effects of intraoperative low dose ketamine on remifentanil-induced hyperalgesia in gynecologic surgery with sevoflurane anesthesia

Background Remifentanil is useful during general anesthesia because of its rapid onset and short acting time. However, some studies report that due to opioid-induced hyperalgesia (OIH) and tolerance, remifentanil also increases early postoperative pain. The occurrence of OIH and opioid-induced tolerance is mainly thought to be due to central sensitization by the activation of NMDA receptors. Therefore, we investigated the effects of continuous infusion of ketamine, an NMDA receptor antagonist, on postoperative pain and the quantity of opioids used. Methods 40 patients scheduled to undergo laparoscopic gynecologic surgery were randomly allocated into two groups. Anesthesia was equally maintained with sevoflurane and 4 ng/ml of remifentanil in all patients. Ketamine (0.3 mg/kg) was injected and followed with a continuous dosage of 3 µl/kg/min in the ketamine group (n = 20) while the control group was injected and infused with an equal amount of normal saline. We compared postoperative VAS up to 7 hours and morphine demand through PCA. Results Postoperative VAS and morphine demand was significantly lower in the ketamine group 2 and 3 hours after surgery, respectively. Conclusions When general anesthesia is maintained with sevoflurane and remifentanil in patients undergoing laparoscopic gynecologic surgery, continuous infusion of low dose ketamine decreased early postoperative pain and the quantity of opioids used.

Antinociceptive Effects of Intraperitoneal and Intrathecal Vitamin E in the Rat Formalin Test

Background Vitamin E is widely known to be one of the reactive oxygen species (ROS) scavengers and a drug that can easily be obtained, and it has been shown to attenuate the pain responses induced by various causes in animal pain models. Thus, this experiment was conducted to assess the antinociceptive effects of vitamin E by comparing intraperitoneal and intrathecal injections in rats subjected to the formalin test. Methods After the intraperitoneal and intrathecal injections of vitamin E were carried out, respectively (IP: 500 mg/kg, 1 g/kg, and 2 g/kg, IT: 3 mg/kg, 10 mg/kg, and 30 mg/kg), the formalin test was perfumed. As soon as 5% formalin was injected into left hind paw, the number of flinches induced by pain was measured at 5-minute intervals for 1 hour. Results Formalin injected into the left hind paw induced biphasic nociceptive behavior in all animals. Intraperitoneal injection of vitamin E diminished the nociceptive behavior in a dose-dependent manner during the early and late phase. Intrathecal vitamin E diminished nociceptive behavior dose dependently during the late phase but showed no significant difference in the early phase. Conclusions Vitamin E attenuated acute nociception when it was injected systemically, while both systemic and intrathecal injection produced analgesia in a rat model of formalin-induced hyperalgesia.

Antinociceptive effect of phenyl N-tert-butylnitrone, a free radical scavenger, on the rat formalin test

Background Reactive oxygen species (ROS) such as superoxide radicals, hydrogen peroxide, nitric oxide, and nitroperoxide, cause oxidative stress which interferes with normal cell functioning, resulting in cell damage. It is reported to be associated with chronic pain, especially neuropathic pain, and inflammatory pain. ROS is also closely related to central sensitization. Therefore, this study was designed to explore the effects of Phenyl N-tert-butylnitrone (PBN), an ROS scavenger, in acute, continuous, and increasing pain caused by central sensitization. Methods Male Sprague-Dawley rats were divided into 2 groups, an intraperitoneal group (IP) and an intrathecal group (IT), and once again divided into an experimental group and a control group. The experimental group was injected with Phenyl N-tert-butylnitrone (PBN), a free radical scavenger, either intraperitoneally or intrathecally. After inducing pain by injecting formalin into the hind paw, pain behaviors were measured. Lumbar enlargement immmunohistochemistry was performed to assess nitrotyrosine, an oxidative stress marker, to identify the degree of protein nitration. Results Both experimental groups of IP and IT showed statistically significant decreases in the number of flinches compared to the control group in phase 1 and 2. Immunohistochemical evaluation in the control group revealed an increase in nitrated proteins in the gray matter of the lumbar spinal cord, but a significant decrease in nitrated proteins in the gray matter of lumbar spinal cord of the experimental group. Conclusions Intraperitoneal and intrathecal administration of PBN decreases analgesic behaviors, allowing us to believe that ROS is mainly responsible for acute pain and central sensitization.

Antinociceptive drug interaction between intrathecal vitamin E and gabapentin in the rat formalin test

Background Gabapentin is thought to exert an effect through the voltage-dependent calcium channel. Vitamin E is a widely known antioxidant which neutralizes the harmful effect of ROS which is considered to play a prominent role in various painful conditions. This study was therefore conducted to assess the antinociceptive effects of gabapentin and vitamin E and the interaction of these drugs in the modulation of pain in rats subjected to a formalin test. Methods Sprague-Dawley rats with a lumbar intrathecal catheter were tested for their paw flinches by 5% formalin injection after intrathecal injection of gabapentin or vitamin E. After obtaining dose-response curves for each drug, the effect of the combination was tested by the total dose fraction value and isobolographic analysis. Results When a single drug was injected intrathecally, significant dose-dependent decreases in flinches were shown only in the late phase. ED50 values of intrathecal gabapentin and vitamin E in the late phase were 75.3 ± 9.58 µg, and 17.56 ± 1.65 mg/kg respectively. The combination of gabapentin and vitamin E produced dose-dependent decreases in the number of flinches in both phases induced by the formalin test. The ED50 value of the combination was lower than the theoretical additive values in the late phase, but did not show a significant difference with the theoretical additive value. Conclusions Gabapentin and vitamin E (by itself) have no antinociceptive effect in the early phase; however their combination has shown an antinociceptive effect. In addition, they show additive effects in the late phase of the formalin test.

Assessment of airway length of Korean adults and children for otolaryngology and ophthalmic surgery using a fiberoptic bronchoscope

Background Knowledge regarding normal upper airway anatomy is essential for airway management and is required to prevent malpositioning of endotracheal tubes. We evaluated the length of the upper airway in Korean children and adults who had no abnormality of the upper airway using a fiberoptic bronchoscope. Methods Eighty seven patients aged 5 to 81 years undergoing noninvasive elective surgery were included in this study. After induction of anesthesia was complete, we measured the distance from the upper incisor to various components of the upper airway by fiberoptic bronchoscopy. Results In adults, the mean length between the upper incisor and midtrachea was found to be 21.8 ± 1.8 cm in males and 19.9 ± 1.3 cm in females, while the mean length of the trachea was 10.1 ± 1.3 cm in males and 10.3 ± 1.6 cm in females. The length between the upper incisor and midtrachea (IT) were correlated with height both in children (IT [cm] = 2.531 + 0.109 × height [cm]) and adults (IT [cm] = 0.167 + 0.127 × height [cm]), which shows that they differ from the western standard (length of tube [cm] = 5 + 0.1 × height [cm]). Conclusions In adults and children, the length from the incisor to the midtrachea was significantly different when compared with western standards. Therefore, re-evaluation of the proper and precise depth of endotracheal tube in Koreans should be considered.

Thoracic interfascial nerve block for breast surgery in a pregnant woman: a case report

Regional anesthesia for non-obstetric surgery in parturients is a method to decrease patient and fetal risk during general anesthesia. Thoracic interfascial nerve block can be used as an analgesic technique for surgical procedures of the thorax. The Pecs II block is an interfascial block that targets not only the medial and lateral pectoral nerves, but also the lateral cutaneous branch of the intercostal nerve. Pecto-intercostal fascial block (PIFB) targets the anterior cutaneous branch of the intercostal nerve. The authors successfully performed a modified Pecs II block and PIFB without complications in a parturient who refused general anesthesia for breast surgery.

Bone regeneration with umbilical cord blood mesenchymal stem cells in femoral defects of ovariectomized rats

Objectives Current treatments for osteoporosis were prevention of progression, yet it has been questionable in the stimulation of bone growth. The mesenchymal stem cells (MSCs) treatment for osteoporosis aims to induce differentiation of bone progenitor cells into bone-forming osteoblasts. We investigate whether human umbilical cord blood (hUCB)-MSCs transplantation may induce bone regeneration for osteoporotic rat model induced by ovariectomy. Methods The ovariectomized (OVX) group (n = 10) and OVX-MSCs group (n = 10) underwent bilateral ovariectomy to induce osteoporosis, while the Sham group (n = 10) underwent sham operation at aged 12 weeks. After a femoral defect was made at 9 months, Sham group and OVX group were injected with Hartmann solution, while the OVX-MSCs group was injected with Hartmann solution containing 1 × 107 hUCB-MSCs. The volume of regenerated bone was evaluated using micro-computed tomography at 4 and 8 weeks postoperation. Results At 4- and 8-week postoperation, the OVX group (5.0% ± 1.5%; 6.1% ± 0.7%) had a significantly lower regenerated bone volume than the Sham group (8.6% ± 1.3%; 12.0% ± 1.8%, P < 0.01), respectively. However, there was no significant difference between the OVX-MSCs and Sham groups. The OVX-MSCs group resulted in about 53% and 65% significantly higher new bone formation than the OVX group (7.7% ± 1.9%; 10.0% ± 2.9%, P < 0.05). Conclusions hUCB-MSCs in bone defects may enhance bone regeneration in osteoporotic rat model similar to nonosteoporotic bone regeneration. hUCB-MSCs may be a promising alternative stem cell therapy for osteoporosis.

Interventional Removal of Knotted Pulmonary Artery Catheter: A Case Report:

A 60-year-old female patient underwent emergency cadaveric liver transplantation. During the insertion of the pulmonary artery catheter (PAC) through the left innominate vein, advancement of the catheter was not successful and a knot occurred. An interventional radiologist performed antegrade rigid wire insertion into the PAC and succeeded in loosening the knot in the vessel. We report the successful removal of a knot through intervention without additional invasive procedures in a hemodynamically unstable patient with a coagulopathy.

Sedation with dexmedetomidine prolongs the analgesic duration of brachial plexus block: a randomised controlled trial

PURPOSE Dexmedetomidine, an alpha 2 receptor agonist, prolongs nerve block duration when administered in conjunction with peripheral nerve blocks. We hypothesised that sedation with dexmedetomidine could also significantly prolong the analgesic duration of brachial plexus block (BPB) during orthopaedic surgery on the upper extremities. MATERIALS AND METHODS One hundred and two patients received upper extremity surgery under BPB. The patients were randomly sedated with dexmedetomidine (D group) or midazolam (M group) following BPB using 25 mL of local anaesthetics (1:1 mixture of 1% lidocaine and 0.75% ropivacaine). Adequate sedation was evaluated with the modified Ramsay Sedation Scale. Primary outcome was measured as the time the patient first requested analgesic via a patient-controlled analgesia device. Total opioid consumption during the first 24 post-operative hours was also measured as secondary outcomes. RESULTS Time to first request for analgesia (mean ± standard deviation) was significantly longer in the D group (616.9 ± 158.2 min) than in the M group (443.7 ± 127.2 min) (P < 0.001, Mean difference [95% CI] 173.2 [114.8-231.5] min). Total opioid consumption were significantly lower in the D group (fentanyl equivalent, 280.0 μg [171.3;374.0] vs. 363.9 μg [208.3;570.1], P = 0.01). Although patients in the D group showed deeper sedation over time (P < 0.001), PACU stay time was only slightly extended in D group (5.2 [1.2-9.2] min). Perioperative complications did not differ in the two groups. CONCLUSION Sedation with dexmedetomidine not only prolongs analgesic duration of BPB, but also reduces total opioid consumption during the first 24 post-operative hours.

Effect of an epinephrine mixture for interscalene block on hemodynamic changes after the beach chair position under general anesthesia: a retrospective study

Background The beach chair position (BCP) can cause significant hypotension. Epinephrine is used to prolong the duration of local anesthetics; it is also absorbed into blood and can exert systemic effects. This study determined the effects of epinephrine mixed with ropivacaine for an interscalene block (ISB) on hemodynamic changes related to BCP. Methods Patient data collected from March 2013 to August 2014 were used retrospectively. We divided the patients into three groups: 1) ISB only, 2) I+G (general anesthesia after ISB without epinephrine), and 3) I+E+G (general anesthesia after ISB with epinephrine). Mean blood pressure (MBP) and heart rate (HR) were measured for 30 minutes at 5-minute intervals. Results The study analyzed data from 431 patients. MBP tended to decrease gradually in the groups I+G and I+E+G. There were significant differences in MBP between the groups I+G and I, and between the groups I+G and I+E+G. Group I+E+G showed a significant increase in HR compared with the other two groups. Conclusions ISB with an epinephrine mixture did not prevent hypotension caused by the BCP after general anesthesia. HR increased only in response to the epinephrine mixture. A well-planned prospective study is required to compare hemodynamic changes in that context.