bluuebunny/crossref_metadata_2025_split huggingface dataset:
Acetylcholinesterase and Butyrylcholinesterase Are Expressed in the Spinal Meninges of Monkeys and Pigs
Authors: Ummenhofer Wolfgang C. , Brown Sean M. , Bernards Christopher M. 
Published: November 2003

Background
Acetylcholinesterase inhibition at the spinal level has been shown to produce a potent antinociceptive effect. However, the site of cholinesterase inhibition is unknown. To determine whether the spinal meninges participate in acetylcholine metabolism, the spinal meninges of monkeys and pigs were assayed for cholinesterase activity.

Methods
Spinal cord, dura mater, and arachnoid mater specimens from anesthetized pigs and monkeys were mechanically homogenized and cholinesterase activity was determined quantitatively using a commercially available colorimetric assay. The ability of neostigmine to inhibit cholinesterase activity in vitro was also measured. Finally, the reverse transcriptase polymerase chain reaction (RT-PCR) was used to identify the cholinesterase metabolizing enzymes expressed by the spinal meninges.

Results
All spinal cord and meningeal specimens showed cholinesterase activity. In pigs, the dura mater showed less enzyme activity (36 +/- 17.7 U/mg protein) than the arachnoid mater (73.4 +/- 30.3 U/mg protein; P < 0.05), and the arachnoid mater showed less activity than the spinal cord (131.3 +/- 55.2 U/mg protein; P < 0.05). In monkeys, the dura mater again showed less cholinesterase activity (45.8 +/- 20.1 U/mg protein; P < 0.05), whereas cholinesterase activity in the arachnoid mater (90.3 +/- 45.9 U/mg protein) and spinal cord specimens (101.9 +/- 37.5 U/mg protein) were not significantly different. There were no significant species-related differences in cholinesterase activity. Neostigmine inhibited cholinesterase activity in a log-dose-dependent manner. The RT-PCR identified mRNA for acetylcholinesterase and butyrylcholinesterase in monkey pia-arachnoid mater.

Conclusions
These data show that the spinal meninges express acetylcholinesterase and butyrylcholinesterase; for monkeys, although not pigs, the level of cholinesterase activity is comparable with that found in the spinal cord. This finding suggests that the meninges may be an important site for acetylcholine metabolism and may play a role in the analgesic effect produced by intrathecally administered cholinesterase inhibitors.
Intravenous Lidocaine Attenuates Acute Lung Injury Induced by Hydrochloric Acid Aspiration in Rabbits
Authors: Nishina Kahoru , Mikawa Katsuya , Takao Yumiko , Shiga Makoto , Maekawa Nobuhiro , Obara Hidefumi 
Published: November 2003

Background
Neutrophils play a crucial role in the pathogenesis of acid-induced acute lung injury. Lidocaine inhibits the function of neutrophils. This study aimed to determine whether lidocaine attenuates acute lung injury induced by hydrochloric acid (HCl) instillation.

Methods
In study 1, rabbits were divided into four groups (n = 7 each). Lung injury was induced by intratracheal HCl (0.1 N, 3 ml/kg) in two groups. The other two groups received saline intratracheally. Lidocaine given intravenously (2 mg/ g bolus + 2 mg x kg(-1) x h(-1) infusion) was started 10 min before intratracheal instillation in one HCl and one saline group, and saline was given intravenously in the other two groups. In study 2, rabbits (four groups of seven animals each) received HCl (0.1 N, 3 ml/kg) intratracheally. Treatment with intravenous lidocaine was started 10 min before, 10 min after, or 30 min after acid instillation, or saline was given intravenously 10 min before instillation.

Results
In study 1, HCl caused deterioration of the partial pressure of oxygen (PaO2), lung leukosequestration, decreased lung compliance, and increased the lung wet-to-dry weight ratio and albumin, interleukin-6 (IL-6), and IL-8 levels in bronchoalveolar lavage fluid. Lidocaine pretreatment attenuated these changes. Hydrochloric acid increased superoxide anion production by neutrophils and caused morphologic lung damage, both of which were lessened by lidocaine. In study 2, lidocaine given 10 min after acid instillation was as effective as pretreatment in PaO2, lung mechanics, and histologic examination. However, PaO2 changes in lidocaine 30 min after injury were similar to those in saline given intravenously.

Conclusions
Intravenous lidocaine started before and immediately after acid instillation attenuated the acute lung injury, in part by inhibiting the sequestration and activation of neutrophils.
Ketorolac and Enoxaparin Affect Arterial Thrombosis and Bleeding in the Rabbit
Authors: Delaporte-Cerceau Sonia , Samama Charles-Marc , Riou Bruno , Bonnin Philippe , Guillosson Jean-Jacques , Coriat Pierre 
Published: November 2003

Background
Nonsteroidal anti-inflammatory drugs (NSAIDs) may interfere with hemostasis during the perioperative period, and the combination of NSAID and enoxaparin could increase this effect. The aim of this prospective, blinded experimental study was to assess these effects using a model of arterial thrombosis and bleeding in the rabbit.

Methods
After anesthesia was induced and monitors placed, the common carotid arteries were exposed, and 60% stenosis of the right common carotid artery was produced. Twenty minutes later, a compression injury of the artery was produced that triggered a series of cyclic episodes of thrombosis and clot lysis. This was manifested as cyclic flow reductions (CFR; measured with an electromagnetic flow meter). After the first flow reduction was noted, the rabbits were immediately and randomly assigned to one of four groups (n = 10 each) that received intravenous infusions: control, ketorolac (2 mg/kg), enoxaparin (0.5 mg/kg), and ketorolac plus enoxaparin (2 mg/kg and 0.5 mg/kg, respectively). The number of CFRs that occurred in the subsequent 20-min period was used as a measure of treatment effect. The contralateral common carotid artery was exposed, and both stenosis and injury were produced. The ability of the administered drug to prevent thrombosis was assessed as the number of CFRs that occurred during the first 20-min period after vessel injury. In addition, both before and after group assignment and drug injection, bleeding times were noted and a platelet aggregation test was performed. Laparotomy was followed by a spleen section, and the extent of the wound and the amount of splenic bleeding were measured.

Results
The treatment effect was indicated by the median number of CFRs, which was 5.5 in the control group, 1 in the ketorolac group, 2 in the enoxaparin group, and 0 in the ketorolac + enoxaparin group. The prevention effect was indicated by the median number of CFRs, which was 4 in the control group, 0 in the ketorolac group, 2 in the enoxaparin group, and 0.5 in the ketorolac + enoxaparin group. Bleeding time was significantly lengthened in the enoxaparin and in the ketorolac + enoxaparin groups. Splenic and wound bleeding was greater in the ketorolac group. Platelet aggregation was completely inhibited in the ketorolac and the ketorolac + enoxaparin groups.

Conclusions
Ketorolac had an important antithrombotic activity. The association of enoxaparin with ketorolac seemed to lengthen the bleeding time observed with ketorolac.
A Method to Compare Costs of Drugs and Supplies among Anesthesia Providers
Authors: Dexter Franklin , Lubarsky David A. , Gilbert Bill C. , Thompson Christine 
Published: November 2003

Background
Comparison of costs among anesthesia providers using "cost per case" does not adjust for variations in casemix (such as the type of procedure and patient condition). The authors propose an alternative method for comparing costs using the American Society of Anesthesiologists' Relative Value Scale (ASARVS) system, which incorporates basic units (for the procedure), modifier units (for the patient's physical condition), "other" units (such as for the placement of invasive monitors), and time units (proportional to the case duration).

Methods
Data were obtained from a series of 3,340 anesthetics performed at a tertiary hospital. Administered and discarded drug, supply, and fluid costs were used.

Results
Costs expressed as dollars per ASARVS unit had 54% less variability than costs expressed as dollars per case (P < 0.0001). Pearson correlations between demographic variables and cost per ASARVS unit ranged from -0.10 to 0.13. Total (e.g., quarterly) costs for simulated sets of cases were predicted within 0.0 +/- 2.3% by multiplying (1) their sum of units and (2) a like set of case's sum of costs divided by sum of units.

Conclusions
Costs of anesthetic supplies and drugs of a case were more accurately reported as "cost per unit" than as "cost per case." This method of calculating the cost of anesthetic drugs and supplies has several applications, including (1) comparison of costs among anesthesia providers and (2) benchmarking costs among hospitals and anesthesia groups. By design, anesthesia providers' time is quantified by their ASARVS units. Together anesthesia costs (personnel, supplies, and drugs) are better reported as "cost per unit" than as "cost per case."
Perioperative Cost-finding Analysis of the Routine Use of Intraoperative Forced-air Warming during General Anesthesia
Authors: Fleisher Lee A. , Metzger Scott E. , Lam Janet , Harris Andrew 
Published: November 2003

Background
Despite the well-documented ability of forced-air warming (FAW) to maintain normothermia, it is unclear whether this technique results in a net increase or decrease in costs. The authors did a prospective cost-finding study comparing FAW with routine thermal care in patients at low risk for perioperative complications who were undergoing general anesthesia.

Methods
After institutional review board approval was received, 100 patients were studied who were having elective surgery scheduled for more than 2 h during general endotracheal anesthesia. Patients were randomly assigned to one of two groups: FAW or routine thermal care. All patients received a standardized anesthetic. Anesthesia providers were blinded to core temperatures and the use of FAW. Primary outcomes were those associated with perioperative costs.

Results
The time from completion of surgical dressing until tracheal extubation was significantly reduced in the FAW group (10 +/- 1 min compared with 14 +/- 1 min; mean +/- SEM; P < 0.01). There was no demonstrable difference in attainment of postanesthesia care unit discharge criteria between the two groups, although the FAW group used one less cotton blanket there. The net savings related to the use of the FAW depends on the percentage of the intraoperative costs that are fixed rather than variable ($15 additional for FAW if all costs are fixed compared with $29 savings if all costs were variable).

Conclusions
Routine intraoperative FAW significantly reduced time until extubation and use of cotton blankets in the postanesthesia care unit. These results suggest that the influence of FAW on net total perioperative costs depends on patient and surgical characteristics and institutional factors related to cost accounting.
Do Shorter-acting Neuromuscular Blocking Drugs or Opioids Associate with Reduced Intensive Care Unit or Hospital Lengths of Stay after Coronary Artery Bypass Grafting?
Authors: Butterworth John , James Robert , Prielipp Richard C. , Cerese Julie , Livingston Jean , Burnett David A. 
Published: November 2003

Background
The authors hypothesized that shorter-acting opioid and neuromuscular blocking drugs would be associated with reductions in duration of intubation, length of stay (LOS) in the intensive care unit (ICU) after tracheal extubation, or postoperative (exclusive of ICU) LOS, and that shorter durations of intubation would be associated with reduced ICU LOS after extubation and postoperative (exclusive of ICU) LOS.

Methods
One-thousand ninety-four patients undergoing primary coronary artery bypass graft surgery at 40 academic health centers were studied. Multiple patient-related factors were included in multivariate models for hypothesis testing.

Results
The duration of tracheal intubation, ICU LOS after extubation, and postoperative (exclusive of ICU) LOS all varied significantly by site. There was no difference between vecuronium and pancuronium in duration of intubation, ICU LOS after extubation, or postoperative (exclusive of ICU) LOS. Use of sufentanil rather than fentanyl was associated with a significant (P=0.045) reduction of 1.9 h (95% CI, 0.04 to 4.1 h) in duration of tracheal intubation but had no significant effect on ICU LOS after extubation, total ICU LOS, postoperative (exclusive of ICU) LOS, or total postoperative LOS. The authors' best model predicts a complex association between increasing duration of intubation and both ICU LOS after tracheal extubation and postoperative (exclusive of ICU) LOS, which was associated with an increase in those measures when duration of intubation exceeded 7.3 or 3 h, respectively.

Conclusions
The LOS measures varied considerably among the institutions. Use of shorter-acting opioid and neuromuscular blocking drugs had no association with ICU LOS after tracheal extubation or with postoperative (exclusive of ICU) LOS. Only when the duration of intubation exceeded threshold values was it associated with increased LOS measures.
Early Extubation following Cardiac Surgery in a Veterans Population
Authors: London Martin J. , Shroyer Laurie A. , Coll Joseph R. , MaWhinney Samantha , Fullerton David A. , Hammermeister Karl E. , Grover Frederick L. 
Published: November 2003

Background
Early tracheal extubation is an important component of the "fast track" cardiac surgery pathway. Factors associated with time to extubation in the Department of Veterans Affairs (DVA) population are unknown. The authors determined associations of preoperative risk and intraoperative clinical process variables with time to extubation in this population.

Methods
Three hundred four consecutive patients undergoing coronary artery bypass graft, valve surgery, or both on a fast track clinical pathway between October 1, 1993 and September 30, 1995 at a university-affiliated DVA medical center were studied retrospectively. After univariate screening of a battery of preoperative risk and intraoperative clinical process variables, stepwise logistic regression was used to determine associations with tracheal extubation < or = 10 h (early) or > 10 h (late) after surgery. Postoperative lengths of stay, complications, and 30-day and 6-month mortality rates were compared between the two groups.

Results
One hundred forty-six patients (48.3%) were extubated early; one patient required emergent reintubation (0.7%). Of the preoperative risk variables considered, only age (odds ratio, 1.80 per 10-yr increment) and preoperative intraaortic balloon pump (odds ratio, 7.88) were multivariately associated with time to extubation (model R) ("late" association is indicated by an odds ratio >1.00; "early" association is indicated by an odds ratio <1.00). Entry of these risk variables into a second regression model, followed by univariately significant intraoperative clinical process variables, yielded the following associations (model R-P): age (odds ratio, 1.86 per 10-yr increment), sufentanil dose (odds ratio, 1.54 per 1-microg/kg increment), major inotrope use (odds ratio, 5.73), platelet transfusion (odds ratio, 10.03), use of an arterial graft (odds ratio, 0.32), and fentanyl dose (odds ratio, 1.45 per 10-microg/kg increment). Time of arrival in the intensive care unit after surgery was also significant (odds ratio, 1.42 per 1-h increment). Intraoperative clinical process variables added significantly to model performance (P < 0.001 by the likelihood ratio test).

Conclusions
In this population, early tracheal extubation was accomplished in 48% of patients. Intraoperative clinical process variables are important factors to be considered in the timing of postoperative extubation after fast track cardiac surgery.
Prophylactic Angiotensin II Infusion during Spinal Anesthesia for Elective Cesarean Delivery
Authors: Vincent Robert D. , Werhan Carol F. , Norman Patricia F. , Shih Grace H. , Chestnut David H. , Ray Tapati , Ross Elaine L. , Bofill James A. , Shaw Douglas B. 
Published: November 2003

Background
Angiotensin II may prove useful in treating regional anesthesia-induced hypotension in obstetric patients, because it causes less uterine vasoconstriction than do other vasoconstrictor drugs (such as phenylephrine). This study compared (1) maternal blood pressure and heart rate and (2) fetal status at delivery in parturients given either prophylactic angiotensin II or ephedrine infusion during spinal anesthesia for elective cesarean delivery.

Methods
Fifty-four women were randomized to receive either angiotensin II or ephedrine infusion intravenously during spinal anesthesia for elective cesarean section delivery. Simultaneous with subarachnoid injection, infusion of angiotensin II (2.5 microg/ml) or ephedrine (5 mg/ml) was initiated at 10 ng x kg(-1) x min(-1) and 50 microg x kg(-1) x min(-1), respectively. The rate of each infusion was adjusted to maintain maternal systolic blood pressure at 90-100% of baseline.

Results
Cumulative vasopressor doses (mean+/-SD) through 10, 20, and 30 min were 150+/-100, 310+/-180, and 500+/-320 ng/kg in the angiotensin group and 480+/-210, 660+/-390, and 790+/-640 microg/kg in the ephedrine group. Maternal heart rate was significantly higher (P < 0.001) during vasopressor infusion in the ephedrine group than in the angiotensin group. Umbilical arterial and venous blood pH and base excess were all significantly higher (P < 0.05) in the angiotensin group than in the ephedrine group.

Conclusions
Angiotensin II infusion maintained maternal systolic blood pressure during spinal anesthesia without increasing maternal heart rate or causing fetal acidosis.
Causes and Prediction of Maldistribution during Continuous Spinal Anesthesia with Isobaric or Hyperbaric Bupivacaine
Authors: Biboulet Philippe , Capdevila Xavier , Aubas Pierre , Rubenovitch Josh , Deschodt Jacques , d'Athis Francoise 
Published: November 2003

Background
Many cases of cauda equina syndrome after maldistribution of local anesthetics during continuous spinal anesthesia have been reported. In experiments, a caudad route of catheter travel and the use of hyperbaric agents have been shown to induce these limited blocks. The aim of this clinical study was to verify this hypothesis and seek a predictive factor for the maldistribution of bupivacaine.

Method
Continuous spinal anesthesia via a 19-gauge end port spinal catheter was performed in 80 elderly patients randomly assigned to receive either isobaric or hyperbaric solutions. Successive injections of 2.5 mg bupivacaine were performed at 5-min intervals until a sensory level at or cranial to T8 was obtained. Maldistribution was defined by a sensory level caudal to T12 despite a total dose of 17.5 mg of either isobaric or hyperbaric bupivacaine. After surgery, all catheters were injected with contrast media and examined radiographically.

Results
The frequency of maldistribution was not significantly different in the isobaric and hyperbaric groups. A caudally oriented catheter tip was found to be a major cause of maldistribution (P < 10(-5)). A thoracic sensory level could be reached in all patients presenting a limited block by simply changing the baricity of the bupivacaine, the position of the patient, or both. The sensory level obtained 10 min after the first injection of 2.5 mg isobaric or hyperbaric bupivacaine was found to be a predictive factor of maldistribution.

Conclusions
Hyperbaric solutions do not appear to be a clinical factor in the development of limited block. The principle factor causing the maldistribution of bupivacaine is the caudal orientation of the tip of the end-hole catheter rather than its level or the route of catheter travel.
Treatment of Incomplete Analgesia after Placement of an Epidural Catheter and Administration of Local Anesthetic for Women in Labor
Authors: Beilin Yaakov , Zahn Jeffrey , Bernstein Howard H. , Zucker-Pinchoff Barbara , Zenzen Wendy J. , Andres Lewis A. 
Published: November 2003

Background
Approximately 15% of women still have pain after placement of an epidural catheter and administration of local anesthetic for labor analgesia. Two techniques frequently used to treat this pain were compared: (1) withdrawal of the catheter 1 cm and repeated dosing with additional local anesthetic, and (2) repeated dosing with additional local anesthetic without any catheter manipulation.

Methods
Fifteen minutes after placement of a multiple-orifice epidural catheter 5 cm into the epidural space and administration of 13 ml 0.25% bupivacaine to the parturient in labor, the adequacy of analgesia was assessed. All women who had incomplete analgesia were randomized (first intervention) to receive an additional 5 ml 0.25% bupivacaine (local-anestheticonly group) or to receive 5 ml 0.25% bupivacaine after first withdrawing the epidural catheter 1 cm (catheter-manipulation group). If after 15 min the woman still had pain, then (second intervention) the catheter was withdrawn 1 cm and an additional 5 ml 0.25% bupivacaine was administered to the local-anesthetic-only group, whereas 5 ml 0.25% bupivacaine was given to the catheter-manipulation group without further catheter manipulation. The success rate of the second intervention was assessed 15 min later.

Results
Seventy-eight women were enrolled in the study, 39 to each group. In the local-anesthetic-only group, 29 (74%) women were successfully treated with the first intervention and the remaining 10 (100%) were successfully treated with the second intervention. In the catheter-manipulation group, 30 (77%) were successfully treated with the first intervention and 7 (100%; 2 patients were not studied because of investigator error) were successfully treated with the second intervention (P=NS).

Conclusions
Administration of additional local anesthetic without first withdrawing the epidural catheter will effectively treat most women for whom analgesia is incomplete after the placement of an epidural catheter during labor.
Epidural Fentanyl Produces Labor Analgesia by a Spinal Mechanism
Authors: D'Angelo Robert , Gerancher J. C. , Eisenach James C. , Raphael Brenda L. 
Published: November 2003

Background
The purpose of this study was to determine if epidural fentanyl produces analgesia in laboring patients by a primary spinal or supraspinal action.

Methods
Fifty-four parturients were randomized to receive epidural 0.125% bupivacaine plus one of three treatments: epidural saline-intravenous saline, epidural fentanyl (20 microg/h)-intravenous saline, or epidural saline-intravenous fentanyl (20 microg/h). The study treatments were administered by continuous infusion, whereas epidural bupivacaine use was patient controlled.

Results
Epidural bupivacaine use was significantly reduced by epidural (11.5+/-4.6 ml/h) but not by intravenous fentanyl (15.9+/-4.5 ml/h) compared with saline control (16+/-5.9 ml/ h). Analgesia characteristics and side effects were similar among groups.

Conclusions
Low-dose epidural infusions of fentanyl produce labor analgesia by a primary spinal action.