Jong Hun Jun

The Effect of Intrathecal Gabapentin and 3-isobutyl gamma-aminobutyric Acid on the Hyperalgesia Observed After Thermal Injury in the Rat

Gabapentin is an anticonvulsant that may represent a novel class of drugs, which has novel spinal antihyperalgesic activity.We sought to characterize this spinal action in a model of hyperalgesia that involves a mild thermal injury to the hind paw of the rat. Rats were prepared with chronic spinal catheters. Under brief halothane anesthesia, a thermal injury was induced by applying the left hind paw to a thermal surface (52.5[degree sign]C) for 45 s. This exposure results in mild erythema but no blistering. Thermal escape latency of the hind paw was determined using an underglass thermal stimulus with which response latencies of the injured and uninjured (normal) paw could be obtained. Thirty minutes after thermal injury, the response latency in all groups decreased from 10-12 s to 5-7 s. Uninjured paw withdrawal latency was unaltered. The intrathecal injection of gabapentin (30-300 micro g) produced a dose-dependent reversal of the hyperalgesia but had no effect on the response latency of the normal hind paw, even at the largest doses. A similar reversal was observed after intrathecal delivery of the structural analog S(+)-3-isobutyl gamma-aminobutyric acid (GABA) (30-300 micro g), but not after the largest dose of its stereoisomer R(-)-3-isobutyl GABA (300 micro g). The effects of both intrathecal gabapentin and S(+)-3-isobutyl GABA were reversed by intrathecal D-serine, but not L-serine. All effects were observed at doses that had no significant effect on motor function. These observations, in conjunction with the accumulating data on binding and transmitter release, emphasize that these gabapentinoids can selectively modulate the facilitation of spinal nociceptive processing otherwise generated by persistent small afferent input generated by tissue injury. Implications: Gabapentin and its analog, 3-isobutyl gamma-aminobutyric acid, given spinally, produce a dose-dependent, D-serine-sensitive reversal of the thermal hyperalgesia evoked by mild thermal injury. (Anesth Analg 1998;86:348-54)

The effect of intrathecal mu, delta, kappa, and alpha-2 agonists on thermal hyperalgesia induced by mild burn on hind paw in rats

PurposeMild cutaneous thermal injury, leading to a first-degree burn, induces a sensation of burning pain and enhances the pain sensitivity of the skin. Opioid and α2 receptor agonists are commonly used to reduce such hyperalgesia. We investigated conditions that induced adequate thermal hyperalgesia in rats and compared the effects of μ, δ, κ, and α2 receptors at the level of the spinal cord in this model.MethodsA total of 149 male Sprague–Dawley rats were submitted to this study. A first-degree burn injury was induced in the hind paw by contact with a hot plate. The nociceptive threshold was determined by measuring the time from the application of a light beam to the hind paw to the withdrawal response (paw withdrawal latency, PWL). Various hot-plate exposure times and light beam intensities were tested to determine the conditions that induced adequate hyperalgesia. We also tested the effects of intrathecal morphine (μ agonist), DPDPE ([D-Pen2, D-Pen5] enkephalin, a δ agonist), U50488H (trans(+)-3,4-dichloro-N-methyl-N-[2-(1-pyrrolidinyl) cyclohexyl]-benzacetamide methane sulfonate salt, a κ agonist), and ST-91 (2-[2,6-diethyl-phenylamino]-2-imidazoline, an α2 agonist) on PWL.ResultsA first-degree burn was induced by contact with the hot plate for 45 s. Using current of 5.0 A, PWL was reduced by 40% from baseline. Intrathecally administered morphine, DPDPE, and ST-91, but not U50488H, showed dose-dependent antinociceptive effects in both injured and normal paws.ConclusionsBased on these findings, we could find adequate conditions for thermal hyperalgesia model. In this experimental model, μ, δ, and α2 receptor agonists produced antinociceptive effects at the level of the spinal cord, but the κ receptor agonist did not.

Bispectral index and their relation with consciousness of the patients who receive desflurane or sevoflurane anesthesia during wake-up test for spinal surgery for correction

Background Wake-up tests may be necessary during surgery for kypho-scoliosis to ensure that spinal function remains intact. It is difficult to predict the time when patients can respond to a verbal command. We evaluated the effectiveness of the bispectral index (BIS) and its relation to patients levels of consciousness in wake-up tests during desflurane and sevoflurane anesthesia. Methods Eighteen patients each were enrolled in the desflurane and sevoflurane groups for spinal correction surgery. We measured BIS values, blood pressure, heart rate, and consciousness state and time, at the points when patients responded during the wake-up test. Results The BIS values when patients made fists upon a verbal command (T3) were 86.7 ± 7.5 for desflurane and 90.3 ± 5.4 for sevoflurane. Patients in the desflurane group had significantly shorter wake up delays than those in the sevoflurane group (6.9 ± 1.8 min vs. 11.8 ± 3.6 min). However, there was no difference between the groups in the time between the response to a verbal command and the time when a patient moved their toes in response to verbal commands. No recall of the wake-up tests occurred in either group. Conclusions The values obtained using the BIS index could to some extent predict the time of a patients and would be informative during desflurane and sevoflurane anesthesia. Moreover, desflurane permitted faster responses to verbal commands than sevoflurane, and allowed the wake-up test to be performed sooner.

Temporary postoperative visual loss associated with intracerebral hemorrhage after laparoscopic appendectomy: a case report

Postoperative visual loss (POVL) after non-ophthalmic surgery is rare, with a reported incidence ranging from 0.013 to 0.2%. Most perioperative visual loss is associated with spine operations and cardiac bypass procedures. The most common cause of POVL is ischemic optic neuropathy. However, there are no previous reports of postoperative visual loss after laparoscopic appendectomy. A 43-year-old female with no underlying disease underwent laparoscopic appendectomy; the operation was completed in one hour and her blood pressure was stable during the perioperative period. In the post-anesthetic care unit, the patient complained of nausea and headache, but she did not complain of any unusual visual symptoms. Approximately one hour after arriving at the ward, the patient complained of visual disturbance. Neurologic examination revealed left homonymous hemianopsia, and subarachnoid hemorrhage and intracerebral hemorrhage were found in the occipital area on brain MRI.

Effect of palmitoylethanolamide on inflammatory and neuropathic pain in rats

Background A growing body of evidence suggests that neuroinflammation, which is characterized by infiltration of immune cells, activation of mast cells and glial cells, and production of inflammatory mediators in the peripheral and central nervous systems, plays an important role in the induction and maintenance of chronic pain. Palmitoylethanolamide (PEA), which is a type of N-acylethanolamide and a lipid, has an anti-inflammatory effect. Relative to the anti-inflammatory effect, little is known about its analgesic effect in chronic pain. This study aimed to determine whether PEA relieves chronic inflammatory and neuropathic pain. Methods Male Sprague-Dawley rats were injured by transection of the left L5 and L6 spinal nerves to induce neuropathic pain or were injected with monoiodoacetic acid into the synovial cavity of knee joints to induce inflammatory pain. To assess the degree of pain, two kinds of stimuli - pressing von Frey filaments and wetting with acetone - were applied to the plantar surface of the rat to measure mechanical and cold sensitivity, respectively. Pain was measured by assessing behavioral responses, including paw withdrawal response threshold and paw withdrawal frequency upon stimulation. Results Neuropathic pain caused by spinal nerve transection (SNT) decreased the mechanical threshold and increased the frequency of response to acetone application. But, cold allodynia caused by SNT did not decrease the withdrawal frequency. Mechanical hyperalgesia caused by chronic inflammation was significantly reduced by both intraperitoneal and intra-articular injections of PEA. Conclusions These outcomes revealed that PEA might be effective in relieving inflammatory and neuropathic pain, especially pain induced by mechanical hyperalgesia, but not cold allodynia.

Acute pulmonary edema due to hypoxia during a difficult intubation in a rheumatoid arthritis patient.

CC We experienced a rheumatoid arthritis (RA) patient who developed acute pulmonary edema by hypoxia in the absence of spontaneous respiratory effort by sufficient muscle relaxation during anesthesia induction. A 61-year-old, 136 cm, 48 kg female patient was treated at our hospital for a bilateral total knee arthroplasty due to RA involving the knee joints. During preoperative evaluation of the patient, her chest radiograph showed a suspicious bronchitis at right lower lobe costophrenic angle area (Fig. 1A), whereas the other laboratory tests showed no specific abnormality. The patient was moved to the operating room to receive bilateral total knee replacement. After normal tidal breathing of 100% oxygen 6 L/min for 3 min using a tightly fitting face mask, anesthesia was induced by injecting 60 mg of propofol and 0.3 μg/kg/min of remifentanil and 30 mg of rocuronium. Under mask ventilation, intubation was performed after 3 min. Intubation was performed using Fiberoptic intubation due to difficulties with endotracheal intubation based on the preoperative cspine radiography finding of atlantoaxial subluxation. Fiberoptic intubation was tried for 3 min but failed, the subsequent mask ventilation was performed for 3 min, during which the patient’s ventilaton was not sufficient but maintained, at that time the SpO2, expired tidal volume and ETCO2 was between 90–95%, 200–400 ml and 40–45 mmHg, respectively. But, a few seconds later, mask ventilation was more inadequate, leading to a decrease in the SpO2 up to 70% and cyanosis. Thus, LMA was immediately inserted for adequate ventilation, and the SpO2 were measured as 90%, the patient’s ventilation was smooth and SpO2 increased to 100%, whereupon LMA-guided fiberoptic intuba tion was successfully performed. Five minutes later, a pinkish foamy secretion was observed in the endotracheal tube, and pulmonary edema was shown by a portable chest radiograph; however, no other abnormality was observed (Fig. 1B). Arterial blood gas analysis (ABGA) at an inspired oxygen fraction of 0.5 showed the following: pH 7.3, PCO2 45 mmHg, PO2 149 mmHg, and BE -2.5 mmol/L. Judging that the pulmonary edema was not serious based on the ABGA and chest radiograph, we proceeded with the surgery as planned and intermittent the endotracheal tube suction for 30 min after initiation of the surgery, until the secretion stopped. The total amount of secretion was

The hemodynamic effects of a reversed Trendelenburg in elderly patients with increased cardiac risk during laparoscopic cholecystectomy

BACKGROUNDnWe studied the hemodynamic changes induced by pneumoperitoneum and a reversed Trendelenburg in elderly patients with increased cardiac risk (ASA class III; n = 30; age 70.8 +/- 4.9 years, mean +/- SD) and compared the results with elderly patients at normal risk (ASA class II; n = 30; age 69.2 +/- 4.1 years) during laparoscopic cholecystectomy.nnnMETHODSnThe transesophageal Doppler monitor was performed after induction of general anesthesia (pre-incision), after onset of pneumoperitoneum (insufflation), after head-up (20degrees) and a left lateral tilt (15degrees) (reversed Trendelenburg) and after deflation and horizontal position (desufflation). Mean arterial pressure (MAP), heart rate, cardiac index (CI) and systemic vascular resistance (SVR) were measured, respectively.nnnRESULTSnInduction of pneumoperitoneum and head-up tilt in patients with cardiac risk resulted significantly in a decrease in CI and an increase in SVR compared with patients with normal risk (P < 0.05), and that remained until deflation, but no interval changes in MAP and heart rate. The CI, MAP and heart rate decreased and SVR increased significantly in patients with cardiac risk compared with patients with normal risk before incision (P < 0.05). No complications occurred. The results indicate that pneumoperitoneum and a reversed Trendelenburg are associated with significant but relatively benign hemodynamic changes.nnnCONCLUSIONSnAnesthesia for laparoscopic cholecystectomy in elderly patients with increased cardiac risk should be performed with an adequate hemodynamic monitoring.