The effects of preoperative intravenous acetaminophen in patients undergoing abdominal hysterectomy.

PURPOSE: Although intravenous acetaminophen is commonly used for the management of postoperative pain, very limited evidence supports the usefulness of preoperative administration. The aim of this study was to determine the analgesic effect of preoperative acetaminophen on opioid consumption, pain scores, and side effects in patients receiving an elective abdominal hysterectomy. METHODS: A randomized, double-blinded, placebo-controlled clinical trial was performed in 76 women undergoing abdominal hysterectomy. Patients received either acetaminophen 2 g (group A) or placebo (group C) intravenously 30 min before surgery under general anesthesia. Postoperative pain was treated with patient-controlled intravenous hydromorphone 0.2 mg bolus. Hydromorphone consumption, pain scores during rest and movement, and any adverse effects were recorded at 1, 2, 6, 12, and 24 h after the operation. RESULTS: Overall hydromorphone consumption was significantly lower in group A compared with group C at all the time points (P = 0.013). The total 24-h hydromorphone consumption was reduced by 30% in group A. There was no significant difference in pain scores. The incidence of postoperative nausea and vomiting after the operation were significantly lower in group A than in group C (P < 0.05). CONCLUSIONS: Premedication with acetaminophen reduced hydromorphone consumption and opioid-related side effect in patients undergoing abdominal hysterectomy, but did not significantly reduce pain intensity.

Micro-CT and Histomorphometric Study of Bone Regeneration Effect with Autogenous Tooth Biomaterial Enriched with Platelet-Rich Fibrin in an Animal Model.

The aim of this study was to evaluate the potential of tooth biomaterials as bone graft biomaterials for bone healing in rabbits. We prepared tooth biomaterial and platelet-rich fibrin (PRF) to fill the round-shaped defect in the skull of New Zealand white rabbits. These cranial defects were treated with different conditions as follows: group 1, a mixture of tooth biomaterials and platelet-rich fibrin (PRF); group 2, only tooth biomaterials; group 3, only PRF; and group 4, the unfilled control group. Specimens of the filled sites were harvested for analysis with microscopic computerized tomography (micro-CT) and histomorphology at 4 and 8 weeks. As a result of micro-CT, at 4 weeks, the bone volume percentages in groups 1 and 2 were 50.33 ± 6.35 and 57.74 ± 3.13, respectively, and that in the unfilled control group was 42.20 ± 10.53 (p = 0.001). At 8 weeks, the bone volume percentages in groups 1 and 2 were 53.73 ± 9.60 and 54.56 ± 8.44, respectively, and that in the unfilled control group was 37.86 ± 7.66 (p = 0.002). The difference between the experimental group 3 and the unfilled control group was not statistically significant. Histomorphologically, the total new bone was statistically different.

Attenuation of neuropathy-induced allodynia following intraplantar injection of pregabalin.

PURPOSE: Pregabalin exhibits potent anticonvulsant, analgesic, and anxiolytic activity in animal models. However, few studies have evaluated pregabalin's potential peripheral effects on neuropathic pain. The aim of this study was to evaluate the peripheral analgesic effects of pregabalin in a rat model of neuropathic pain. METHODS: Male Sprague-Dawley rats were prepared by ligating the left L5 and L6 spinal nerves to produce neuropathic pain. Sixty rats with neuropathic pain were randomly assigned to six groups. Normal saline (control) and pregabalin (10, 20, 30, and 50 mg.kg(-1)) were administered to the plantar surface of the affected left hind paw. Pregabalin (50 mg.kg(-1)) was administered into the unaffected contralateral paw in order to determine its systemic effect. Responses to mechanical, cold, and heat stimulation were recorded at 15, 30, 60, 90, 120, 150, and 180 min after drug administration. Rotarod performance was measured to detect drug-induced side effects, including sedation and reduced motor coordination. RESULTS: Saline injected into the affected paw and a pregabalin dose of 50 mg.kg(-1) injected into the contralateral paw showed no differences for mechanical, cold, and heat allodynia. Administration of pregabalin to the affected left hind paw in the dose range of 10-50 mg.kg(-1) resulted in a dose-dependent increase in thresholds to mechanical, cold, and heat stimulation. CONCLUSION: Peripherally administered pregabalin attenuates mechanical, cold, and heat allodynia in a rat model of neuropathic pain.

Remifentanil Alleviates Propofol-Induced Burst Suppression without Affecting Bispectral Index in Female Patients: A Randomized Controlled Trial.

The bispectral index is affected by various factors, such as noxious stimuli and other drugs, such as muscle relaxants. The burst suppression ratio from bispectral index monitoring is correlated with electroencephalographic burst suppression, which is associated with deep anesthesia, metabolic disorders, and brain injury. We assessed patients undergoing total intravenous anesthesia and examined the effects of remifentanil on the bispectral index, burst suppression ratio, and hemodynamic changes immediately after loss of consciousness with propofol. Seventy American Society of Anesthesiologists physical status class I and II Korean female patients scheduled for general anesthesia were administered propofol with an effect-site concentration of 5 µg/mL, using a target-controlled infusion (TCI). After losing consciousness, patients received either saline or remifentanil at an effect-site concentration of 5 ng/mL for 10 min. During this period, we recorded the bispectral index values, including burst suppression ratio, blood pressure, and heart rate. With remifentanil infusion, burst suppression ratios were lower (p < 0.01) but bispectral values were not different. The burst suppression ratio was significantly different at 6, 7, 8, and 10 min after remifentanil infusion (p < 0.05). In female patients with propofol-induced unconsciousness, remifentanil alleviated the burst suppression ratio without affecting the bispectral value.

Pulmonary edema after catastrophic carbon dioxide embolism during laparoscopic ovarian cystectomy.

Laparoscopy is a surgical procedure used both for diagnosis and for various treatments. A rare but sometimes fatal complication of laparoscopy is pulmonary embolism with CO2 resulting in pulmonary edema. During laparoscopic gynecological surgery in a 29-year-old woman who had previously undergone lower abdominal surgery, the end-tidal CO2 suddenly increased from 40 mmHg to 85 mmHg and then decreased to 13 mmHg with hemodynamic deterioration. These events are characteristic of a CO2 embolism. When this occurred, CO2 insufflation was immediately stopped and the patient was resuscitated. The patient's condition gradually improved with aggressive treatment, but the clinical course was complicated by bilateral pulmonary edema. This case of pulmonary edema was soon resolved with supportive management. The formation of a CO2 embolism during laparoscopy must be suspected whenever there is a sudden change in the end-tidal CO2. In addition, the possibility of pulmonary edema should be considered when a CO2 embolism occurs.

The functional TiO2-biodegradable plastic composite material produced by HVOF spraying process.

Photocatalytic TiO2 coatings on bio-degradable plastic(polybutylene succinate: PBS) were prepared by HVOF spraying using three kinds of agglomerated powders (P200: 200 nm, P30: 30 nm, P7: 7 nm). The microstructures of the coatings were characterized with SEM and XRD analysis, and the photocatalytic efficiency of the coatings was evaluated by photo degradation of gaseous acetaldehyde. For both the HVOF sprayed P200 and P30 coatings, high anatase ratio of 100% was achieved, regardless of the fuel gas pressure. On the other hand, for the HVOF sprayed P7 coating, the anatase ratio decreased from 100% to 49.1% with increasing fuel gas pressure. This decrease may be attributed to the much higher susceptibility to heat of the 7 nm agglomerated powders than the 30 nm and 200 nm agglomerated powders. In terms of the photocatalytic efficiency, HVOF sprayed P200 and P30 coatings seemed to outperform the P7 coatings because of their higher anatase ratios. However, the HVOF sprayed P7 coatings did not show photocatalytic activity possibly because of the extremely small reaction surface area to the photo-catalytic activity and low anatase ratio. Therefore, the present study found that functional PBS plastic with photocatalytic performance could be produced by spraying of ceramics such as TiO2.

The usefulness of the modified laryngoscopic blade for training novice laryngoscopists.

STUDY OBJECTIVE: The objective of this study was to evaluate the effectiveness of a modified Macintosh blade for reducing the chances of directly contacting the teeth and providing a satisfactory laryngoscopic view during laryngoscopies by novice laryngoscopists. DESIGN: This is a prospective clinical comparison study. SETTING: The study took place at an operating room of a university hospital. PATIENTS: Seventy-two patients with American Society of Anesthesiologists physical statuses I and II, aged 16 to 64 years, who were scheduled for elective surgery requiring general anesthesia with endotracheal tube placement participated in this study. INTERVENTIONS: Laryngoscopy was performed twice on each patient, once with a regular Macintosh no. 3 blade and once with a blade in which the flange was partially removed. MEASUREMENTS: As an indirect parameter for anticipating potential dental injury during laryngoscopy, the perpendicular distance from the tip of the maxillary central incisor to the flange of each blade (the blade-tooth distance) was measured when a novice laryngoscopist lifted up the laryngoscope and visualized the glottis. We compared the blade-tooth distances, the chances of directly contacting the tooth, laryngoscopic views, and the subjective feeling of difficulty in handling the laryngoscope between the 2 blades. MAIN RESULTS: Blade-tooth distance varied significantly between the 2 blades: the median/interquartile range was 1.2/2.3 mm vs 3.0/4.3 mm for the regular Macintosh no. 3 and the modified blade, respectively (P<.01). The modified blade was associated with decreased chances of directly contacting the teeth (P<.05). In addition, the modified blade provided a better laryngoscopic view than did the regular blade (P<.01). Most novice laryngoscopists felt that laryngoscopy with the modified blade was significantly easier than that with the regular Macintosh blade (P<.01). CONCLUSIONS: The modified Macintosh blade used in this study proved to be a useful device for training novice laryngoscopists with respect to procedure effectiveness and patient safety.

Apolipoprotein E protects against oxidative stress in mixed neuronal-glial cell cultures by reducing glutamate toxicity.

Apolipoprotein E (ApoE) deficiency has been shown to adversely affect outcome after transient cerebral ischemia and head trauma. Since oxidative stress contributes to these injuries, the ability of ApoE to reduce irreversible oxidative damage was studied in primary mixed neuronal-glial cell cultures. Cells (13-16 days in vitro) were exposed to 50 microM hydrogen peroxide (H2O2) for 30 min, and toxicity was determined by the release of lactate dehydrogenase (LDH) 24 h after exposure. The presence of recombinant human ApoE2 (100, 300, or 1000 nM) in the culture media partially protected against oxidative injury. This protection was not reversed by pre-treatment with receptor associated protein. The NMDA receptor antagonist, MK-801, also provided partial protection against H2O2 toxicity. The degree of protection was similar to that conferred by ApoE treatment. The protective effects of ApoE and MK-801 were not additive; no ApoE protection was observed in cultures treated with MK-801 prior to H2O2 exposure. ApoE treatment had no effect on H2O2 stimulated glutamate release, but did increase the rate of glutamate uptake via the high affinity glutamate transporter in H2O2 treated cultures. Pre-treatment with ApoE also conferred partial protection against glutamate-induced LDH release. Taken together, these findings suggest that ApoE protects mixed neuronal-glial cell cultures against irreversible oxidative injury from H2O2 by reducing secondary glutamate excitotoxicity.

Emergence delirium is related to the invasiveness of strabismus surgery in preschool-age children.

OBJECTIVES: To investigate the correlation between preoperative anxiety and emergence delirium (ED), and to identify other factors that contribute to ED (such as invasiveness of surgery), in preschool-age paediatric patients undergoing strabismus surgery. METHODS: This prospective observational study enrolled Korean children (aged 2-5 years), scheduled for strabismus surgery. After completing the modified Yale Preoperative Anxiety Scale, general anaesthesia was induced. Postoperatively, Pediatric Anesthesia Emergence Delirium (PAED) scores (used as an index of the degree of ED) and a four-point delirium scale (ED incidence), were collected and measured every 5 min. Patients were categorized according to the degree of surgical invasiveness: group U-S, single-muscle correction in a unilateral eye; group U-M, multiple-muscle correction in a unilateral eye; group B-S, single-muscle correction in bilateral eyes; group B-M, multiple-muscle correction in bilateral eyes. RESULTS: A total of 90 paediatric patients participated in the study. Maximum PAED scores did not correlate with the presence of preoperative anxiety. The maximum PAED score of group B-M was significantly higher than scores observed in other groups. CONCLUSIONS: Preoperative anxiety was not related to ED in preschool-age paediatric patients undergoing strabismus surgery. The incidence and severity of ED was higher in patients who underwent more complicated strabismus surgery, compared with those undergoing simpler procedures.

Cardiac arrest with pulmonary edema in a non-parturient after ergonovine administration recovered with extracorporeal membrane oxygenation -A case report-.

Ergonovine have been used for the prevention and treatment of postpartum or postabortion hemorrhage. Although this modality has been considered relatively safe in the obstetric patients, there were a few cardiac events associated with this drug in the post-delivery or post-abortion patients, especially in patients with cardiovascular risk factors. We experienced cardiac arrest in a non-parturient with no discernible risk factors. Although resuscitated, she also suffered from pulmonary edema with unstable hemodynamics and low oxygenation. To manage the patient, extracorporeal membrane oxygenation was used and she recovered successfully without cardiopulmonary complications. Therefore, we recommend that when ergonovine is chosen as a modality, special caution should be paid to the pulmonary events, as well as cardiac, especially when administered by intravenously even in patients with no cardiovascular risk factors. If cardiac events occur, extracorporeal membrane oxygenation or other measures, such as intra-aortic balloon pump can be helpful when conventional cardiopulmonary resuscitation is not effective.

Neurogenic pulmonary edema following intracranial coil embolization for subarachnoid hemorrhage -A case report-.

Neurogenic pulmonary edema (NPE) is a well-known complication of acute central neurologic injury, particularly aneurysmal subarachnoid hemorrhage. Both increased intracranial pressure and severe over-activation of the sympathetic nervous system seem to be pathogenetic for the onset of NPE. Although intracranial endovascular therapy is minimally invasive, it may affect brain stem regions and result in sympathetic activation. We now report the case of a 70-year-old woman who suddenly developed pulmonary edema during coil embolization of a ruptured aneurysm. During the intervention, oxygen saturation declined suddenly and a chest radiograph revealed pulmonary edema. The delayed appearance of NPE in this patient implies a risk for sympathetically mediated NPE during endovascular therapy.

The effects of botulinum toxin A on mechanical and cold allodynia in a rat model of neuropathic pain.

PURPOSE: Botulinum toxin type A (BoNT-A) has been used to treat many disorders related to excessive muscle contraction, but there are few studies evaluating its effects on neuropathic pain. The aim of this study was to evaluate the analgesic effects of BoNT-A in a rat model of neuropathic pain. METHODS: Male Sprague-Dawley rats were prepared by ligating the left L5 and L6 spinal nerves to produce neuropathic pain. Seventy neuropathic rats were randomly assigned into seven groups. Either normal saline or BoNT-A (10, 20, 30 and 40 U.kg(-1)) was administered to the plantar surface of the affected left hind paw, and BoNT-A (30 and 40 U.kg(-1)) was administered into the unaffected right paw in order to determine the drug-induced systemic effect. Mechanical and cold allodynia were observed at pre-administration, one, three, five, seven and 15 days after drug administration, and were quantified by measuring withdrawal frequencies to stimuli with von Frey filament and 100% acetone, respectively. Rotarod performance was measured to detect drug-induced adverse motor effects. RESULTS: The mean minimum withdrawal frequencies to mechanical and cold stimuli were 77 +/- 11 and 90 +/- 4.5%, 46 +/- 5 and 66 +/- 7%, 33 +/- 7 and 62 +/- 7%, 12 +/- 2.9 and 54 +/- 7.3% with 10, 20, 30 and 40 U.kg(-1) BoNT-A respectively (P < 0.05). Doses of 30 and 40 U.kg(-1) BoNT-A resulted in reduced rotarod performance time. CONCLUSION: We conclude that peripherally administered BoNT-A reduces mechanical and cold allodynia in a rat model of neuropathic pain.

Apolipoprotein E protects against NMDA excitotoxicity.

Preclinical and clinical evidence implicates a role for endogenous apolipoprotein E in modifying the response of the brain to focal and global ischemia. To investigate whether apoE modulates the neuronal response to glutamate excitotoxicity, we exposed primary neuronal glial cultures and a neuronal cell line to biologically relevant concentrations of apolipoprotein E prior to NMDA exposure. In both of these paradigms, apolipoprotein E exerted partial protective effects. At neuroprotective concentrations, however, apolipoprotein E failed to block NMDA-induced calcium influx to the same magnitude as the NMDA receptor antagonist MK-801. These results suggest that one mechanism by which apolipoprotein E modifies the central nervous system response to ischemia may be by reducing glutamate-induced excitotoxicity.