Seong Wook Jeong

Acute Respiratory Distress Syndrome Associated With Pulmonary Cement Embolism Following Percutaneous Vertebroplasty With Polymethylmethacrylate

Study Design. A case of acute respiratory distress syndrome following percutaneous vertebroplasty is described. Objective. To alert clinicians to the potential occurrence of acute respiratory distress syndrome following use of polymethylmethacrylate bone cement. Summary of Background Data. Noncardiogenic pulmonary edema has not been reported following intravertebral injection of polymethylmethacrylate. Methods. A 68-year-old woman underwent percutaneous vertebroplasty for a painful L5 compression fracture under local anesthesia. A contralateral transpedicular approach was made to inject polymethylmethacrylate. Results. On the third postoperative day, she developed arthralgia, myalgia, fever, and frequent coughing. Chest radiography revealed bilateral, multifocal, patchy consolidations, suggestive of acute respiratory distress syndrome, and a 5-cm-long tubular radiopacity in the right pulmonary artery. She died 20 days after the vertebroplasty. Conclusion. This case illustrates that clinicians must be aware of the potential occurrence of acute respiratory distress syndrome in patients who received percutaneous vertebroplasty.

Antinociceptive effects and synergistic interaction with morphine of intrathecal metabotropic glutamate receptor 2/3 antagonist in the formalin test of rats.

Spinal metabotropic glutamate receptors (mGluRs) have been known to be involved in the modulation of nociception. While the antinociceptive effects of the mGluR1/5 have been demonstrated, the role of mGluR2/3 for nociception is less clear. This study investigated the effects of an intrathecal mGluR2/3 agonist, APDC, and a mGluR2/3 antagonist, LY341495, for inflammatory and acute pain in the formalin test and thermal stimulation test. We also examined their interaction with intrathecal morphine for the antinociceptive effect. APDC had little effect on the formalin-induced nociception. In contrast, LY341495 caused a dose-dependent suppression of the phase 2 flinching response to the formalin stimulus without affecting phase 1 flinching response. Furthermore, the suppression of pain behavior by LY341495 during phase 2 was reduced significantly by pretreatment with APDC. LY341495 and morphine also showed synergistic drug interaction for antinociception during phase 2 in the formalin test.

The effects of opioids on isolated human pregnant uterine muscles.

We determined the effects of fentanyl, sufentanil, morphine, and meperidine on the spontaneous contractility of isolated human pregnant uterine muscle strips. Uterine specimens were obtained from normal full-term parturients undergoing elective lower-segment cesarean delivery. Longitudinal muscle strips were prepared and mounted vertically in tissue chambers to record their isometric tension. Opioid concentration-response curves were constructed after rhythmic contractions were established. The responses were also examined in the presence of opioid receptor blocker, nitric oxide synthase inhibitor, &bgr;-adrenoceptor blocker, or cyclooxygenase inhibitor. Fentanyl and meperidine inhibited uterine contractility in a concentration-dependent manner, their concentration that inhibited 50% being 2.3 × 10−6 and 1.0 × 10−3M, respectively. Sufentanil and morphine had no significant effects on uterine contractility. Pretreatment with either naloxone, NG-nitro-l-arginine methyl ester, atenolol, or indomethacin did not affect the uterine responses to opioids. These results demonstrate that fentanyl and meperidine may have direct inhibitory effects on the contractility of the human uterus, though at supraclinical concentrations.

Postoperative nausea and vomiting after mastoidectomy with tympanoplasty: a comparison between TIVA with propofol-remifentanil and balanced anesthesia with sevoflurane-remifentanil

Background There is growing interest in the anesthetic approach using total intravenous anesthesia (TIVA) with propofol and remifentanil for the prevention of postoperative nausea and vomiting (PONV). The aim of this study was to compare between the two anesthetic techniques for preventing PONV in the patients undergoing mastoidectomy with tympanoplasty. Methods After obtaining informed consent, 62 patients aged between 20 to 60 years undergoing elective mastoidectomy and tympanoplasty were randomized into two equal study groups: group P/R (n = 31) included patients undergoing TIVA with propofol and remifentanil, and group S/R (n = 31) included patients undergoing balanced anesthesia with sevoflurane and remifentanil. The incidences of PONV and complete response (no PONV, no rescue) were assessed at 1 and 24 h after surgery, using the Rhodes Index. Also, the usage of rescue antiemetics and pain intensity were recorded. Results The Rhodes Index including the occurrence score, distress score and experience score was significantly lower in the P/R group compared to that in the S/R group during the study period (P < 0.05), and the incidence of complete response was significantly higher in the P/R group compared to that in the S/R group, during the first 24 h after surgery. 4 patients in the S/R group requested antiemetics during the first 1 h after surgery. There were no significant differences in pain intensity among groups. Conclusions Compared to balanced anesthesia with sevoflurane and remifentanil, TIVA with propofol and remifentanil was followed by significantly lower incidence and severity of PONV.

Lack of the nitric oxide-cyclic GMP-potassium channel pathway for the antinociceptive effect of intrathecal zaprinast in a rat formalin test

Zaprinast is a phosphodiesterase inhibitor that is active in various models of pain when administered locally. In addition, the antinociception of zaprinast is involved in the nitric oxide (NO)-cGMP pathway. However, the effect of zaprinast administered spinally has not been examined. Therefore, this study examined the effect of zaprinast on the formalin-induced nociception at the spinal level. Next, the role of the NO-cGMP-potassium channel pathway on the effect of zaprinast was further clarified. Catheters were inserted into the intrathecal space of male Sprague-Dawley (SD) rats. Pain was induced by applying 50 microl of a 5% formalin solution to the hindpaw. The change in the zaprinast-induced effect was examined after an intrathecal pretreatment with a NO synthase inhibitor (l-NMMA), a guanylyl cyclase inhibitor (ODQ) or a potassium channel blocker (glibenclamide). Zaprinast produced an antinociceptive effect during phase 1 and phase 2 in the formalin test. Intrathecal l-NMMA, ODQ and glibenclamide did not reverse the antinociception of zaprinast in either phase of the formalin test. These results suggest that zaprinast is effective against both acute pain and the facilitated pain state at the spinal level. However, the NO-sensitive cGMP-potassium channel pathway is not contributable to the antinociceptive mechanism of zaprinast in the spinal cord.

Analysis of Interactions between Serotonin and Gabapentin or Adenosine in the Spinal Cord of Rats

We evaluated the nature of the pharmacologic interaction after concurrent administration of 5-HT–gabapentin and 5-HT–adenosine at the spinal level. Intrathecal catheters were placed in the subarachnoid space of male Sprague-Dawley rats. Nociception was induced by subcutaneous injection of formalin solution (5%, 50 µl) into the hind paw. A fixed dose analysis and an isobolographic analysis were used to determine the properties of interaction. Intrathecal 5-HT dose-dependently suppressed the flinching response during phase 1 of the formalin test, while neither gabapentin nor adenosine affected the phase-1 flinching response. All three intrathecal drugs attenuated the phase-2 flinching response in a dose-dependent manner. The intrathecal combination of 5-HT with a fixed dose of gabapentin or adenosine in phase 1 had little effect or increased the antinociception of 5-HT alone. Isobolographic analysis in phase 2 revealed an additive or a synergistic interaction after intrathecal delivery of 5-HT–gabapentin or 5-HT–adenosine mixture. Taken together, the combination of 5-HT with either gabapentin or adenosine may offer a potential remedy in the treatment of the facilitated state as well as acute pain in the spinal cord.

Evaluation of Interaction between Intrathecal Adenosine and MK801 or NBQX in a Rat Formalin Pain Model

Adenosine and excitatory amino acids have been known to be involved in modulating nociceptive transmission at the spinal level. The authors assessed the characteristics of the interaction of the adenosine-excitatory amino acid antagonist combinations in the spinal cord of rats on the formalin-induced nociception. Intrathecal NMDA antagonist ((5R, 10S)-(+)-5-methyl-10,11-dihydro-5H-dibenzo[a[,]d]cyclohepten-5,10-imine hydrogen maleate, MK801, 30 µg) and AMPA antagonist (2,3-dioxo-6-nitro-1,2,3,4-tetrahydrobenzo[F]quinoxaline-7-sulfonamide, NBQX, 3 µg) decreased the total number of flinches during both phases in the formalin test. Intrathecal adenosine (300 µg) had little effect on the phase 1 flinching response, but decreased the phase 2 response. The fixed dose analysis and the isobolographic analysis revealed that adenosine interacts additively with MK801 and NBQX in the spinal cord.

Spinal 5-HT1A, not the 5-HT1B or 5-HT3 receptors, mediates descending serotonergic inhibition for late-phase mechanical allodynia of carrageenan-induced peripheral inflammation.

Previous electrophysiological studies demonstrated a limited role of 5-hydroxytryptamine 3 receptor (5-HT3R), but facilitatory role of 5-HT1AR and 5-HT1BR in spinal nociceptive processing of carrageenan-induced inflammatory pain. The release of spinal 5-HT was shown to peak in early-phase and return to baseline in late-phase of carrageenan inflammation. We examined the role of the descending serotonergic projections involving 5-HT1AR, 5-HT1BR, and 5-HT3R in mechanical allodynia of early- (first 4h) and late-phase (24h after) carrageenan-induced inflammation. Intrathecal administration of 5-HT produced a significant anti-allodynic effect in late-phase, but not in early-phase. Similarly, intrathecal 5-HT1AR agonist (8-OH-DPAT) attenuated the intensity of late-phase allodynia in a dose dependent fashion which was antagonized by 5-HT1AR antagonist (WAY-100635), but produced no effect on the early-phase allodynia. However, other agonists or antagonists of 5-HT1BR (CP-93129, SB-224289) and 5-HT3R (m-CPBG, ondansetron) did not produce any anti- or pro-allodynic effect in both early- and late- phase allodynia. These results suggest that spinal 5-HT1A, but not 5-HT1B or 5-HT3 receptors mediate descending serotonergic inhibition on nociceptive processing of late-phase mechanical allodynia in carrageenan-induced inflammation.

The effect of priming injection of different doses of remifentanil on injection pain of microemulsion propofol premixed with lidocaine

Background The injection pain of microemulsion propofol is frequent and difficult to prevent. This study examined the prevention of pain during microemulsion propofol injection by pretreatment with different doses of remifentanil or saline, and premixing of lidocaine. Methods One hundred sixty ASA physical status 1-2 adult patients scheduled for elective surgery were enrolled into one of four groups (n = 40, in each). The patients received saline (group LS), remifentanil 0.3 µg/kg (group LR 0.3), remifentanil 0.5 µg/kg (group LR 0.5), or remifentanil 1.0 µg/kg (group LR 1.0), and after 90 seconds received an injection of 2 mg/kg microemulsion propofol premixed with lidocaine 40 mg. Pain was assessed on a four-point scale during microemulsion propofol injection. Results The incidence of microemulsion propofol-induced pain was significantly lower in the LR 0.3, LR 0.5 and LR 1.0 groups than in the LS group (37.5%, 12.5% and 10% vs 65%, respectively). The LR 0.5 and LR 1.0 groups showed significantly less frequent and intense pain than the LR 0.3 group. However, both incidence and severity of pain were not different between LR 0.5 and LR 1.0 groups. Conclusions The combination of remifentanil and lidocaine is effective in alleviating pain associated with a microemulsion propofol injection compared with just lidocaine. Remifentanil 0.5 µg/kg had a similar analgesic effect compared to the 1.0 µg/kg dose.

Anaesthetic requirements and stress hormone responses in acute cord-injured patients undergoing surgery of the injured spine.

Background and objective Neuraxial anaesthesia has been shown to produce a sedative and anaesthetic-sparing effect. The purpose of the present study was to determine the effects of acute spinal cord injury on sevoflurane requirement and stress hormone responses during spinal surgery at the level of the injury. Methods Thirty-five patients with traumatic complete spinal cord injury undergoing spinal surgery at the level of the injury were studied. They were grouped into quadriplegics (above C7, n = 20) and paraplegics (below T1, n = 15) according to the level of injury. Patients (n = 35) with spine trauma without neurological impairment undergoing spinal surgery at the respective level served as controls. The bispectral index score was maintained at 40–50 throughout the surgery. Measurements included end-tidal sevoflurane concentrations, mean arterial pressure, heart rate, and plasma concentrations of catecholamines and arginine vasopressin. Results During the surgery, the mean arterial pressure was significantly lower in both quadriplegics and paraplegics (P < 0.05). The heart rate did not differ significantly in the quadriplegics, but was higher in the paraplegics, compared with their controls. However, end-tidal sevoflurane concentrations and bispectral index score were comparable with controls in both quadriplegics and paraplegics. Throughout the study, the plasma arginine vasopressin concentrations were not altered, although norepinephrine and epinephrine concentrations were lower in the quadriplegics. There were no significant differences in stress hormones between the groups having thoraco-lumbar surgery. Conclusion Spinal cord injury neither alters the anaesthetic requirement regardless of the level of injury during spinal surgery at the level of the injury, nor enhances arginine vasopressin release. However, it blunts catecholamine responses in quadriplegics.