bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analgesia for Labor Pain
Authors: Macario Alex , Scibetta W. Craig , Navarro John , Riley Ed 
Published: November 2003

Background
Epidural analgesia and intravenous analgesia with opioids are two techniques for the relief of labor pain. The goal of this study was to develop a cost-identification model to quantify the costs (from society's perspective) of epidural analgesia compared with intravenous analgesia for labor pain. Because there is no valid method to assign a dollar value to differing levels of analgesia, the cost of each technique can be compared with the analgesic benefit (patient pain scores) of each technique.

Methods
The authors created a cost model for epidural and intravenous analgesia by reviewing the literature to determine the rates of associated clinical outcomes (benefit of each technique to produce analgesia) and complications (e.g., postdural puncture headache). The authors then analyzed data from their institution's cost-accounting system to determine the hospital cost for parturients admitted for delivery, estimated the cost of each complication, and performed a sensitivity analysis to evaluate the cost impact of changing key variables. A secondary analysis was performed assuming that the cost of nursing was fixed (did not change depending on the number of nursing interventions).

Results
If the cesarean section rate equals 20% for both intravenous and epidural analgesia, the additional expected cost per patient to society of epidural analgesia of labor pain ranges from $259 (assuming nursing costs in the labor and delivery suite do not vary with the number of nursing interventions) to $338 (assuming nursing costs do increase as the number of interventions increases) relative to the expected cost of intravenous analgesia for labor pain. This cost difference results from increased professional costs and complication costs associated with epidural analgesia.

Conclusions
Epidural analgesia is more costly than intravenous analgesia. How the cost of the anesthesiologist and nursing care is calculated affects how much more costly epidural analgesia is relative to intravenous analgesia. Published studies have determined that epidural analgesia provides relief of labor pain superior to intravenous analgesia, quantified in one study as 40 mm better on a 100-mm scale during the first stage of labor and 29 mm better during the second stage of labor. Patients, physicians, and society need to weigh the value of improved pain relief from epidural analgesia versus the increased cost of epidural analgesia.
How Much Labor Is in a Labor Epidural?
Authors: Bell Elizabeth D. , Penning Donald H. , Cousineau Edward F. , White William D. , Hartle Andrew J. , Gilbert William C. , Lubarsky David A. 
Published: November 2003

Background
Some anesthesiologists avoid provision of obstetric analgesia services (OAS) because of low reimbursement rates for the work involved. This study defines the manpower costs of operating an OAS in a tertiary referral center and examines reimbursement for this cost.

Methods
The time spent providing OAS in a total of 55 parturients was studied prospectively using a modification of classic time and motion studies.

Results
Mean duration of OAS in our population was 412 +/- 313 min. Mean bedside anesthesia staff time was 90 +/- 40 min, and mean number of visits to each patient's bedside was 6.3 +/- 2.0 visits. Assuming staffing on demand for service (intermittent staffing), a minimum of 2.5 full-time equivalent (FTE) attending anesthesiologists was required to meet demand. With intermittent staffing, labor cost was $325 per patient. Actual practice at Duke University Medical Center is around-the-clock (dedicated) staffing, which requires 4.4 FTEs at a cost of $728 per patient. Neither average indemnity reimbursement ($299) nor Medicaid reimbursement ($204) covered the cost per OAS patient. Breaking even is possible under indemnity reimbursement because operating room reimbursement subsidizes OAS costs. Breaking even cannot occur with Medicaid reimbursement under any circumstances.

Conclusions
Obstetric analgesia services requires a minimum of 2.5 FTE attending anesthesiologists at Duke University Medical Center. With the current payer mix, positive-margin operating room activities associated with the obstetric service are not sufficient to compensate for the losses incurred by an OAS. Around-the-clock dedicated obstetric staffing (4.4 FTEs) cannot operate profitably under any reasonable circumstances at our institution.
Intensive Care Utilization during Hospital Admission for Delivery
Authors: Panchal Sumedha , Arria Amelia M. , Harris Andrew P. 
Published: November 2003

Background
During childbirth, the maternal need for intensive care unit (ICU) services is not well-defined. This information could influence the decision whether to incorporate ICU services into the labor and delivery suite.

Methods
This study reports (1) ICU use and mortality rates in a statewide population of obstetric patients during their hospital admission for childbirth, and (2) the risk factors associated with ICU admission and mortality. A case-control design using patient records from a state-maintained anonymous database for the years 1984-1997 was used. Outcome variables included ICU use and mortality rates.

Results
Of the 822,591 hospital admissions for delivery of neonates during the study period, there were 1,023 ICU admissions (0.12%) and 34 ICU deaths (3.3%). Age, race, hospital type, volume of deliveries, and source of admission independently and in combination were associated with ICU admission (P < 0.05). The most common risk factors associated with ICU admission included cesarean section, preeclampsia or eclampsia, and postpartum hemorrhage (P < 0.001). Black race, high hospital volume of deliveries, and longer duration of ICU stay were associated with ICU mortality (P < 0.05). The most common risk factors associated with ICU mortality included pulmonary complications, shock, cerebrovascular event, and drug dependence (P < 0.05).

Conclusions
This study shows that ICU use and mortality rate during hospital admission for delivery of a neonate is low. These results may influence the location of perinatal ICU services in the hospital setting.
Intraperitoneal and Retroperitoneal Carbon Dioxide Insufflation Evoke Different Effects on Caval Vein Pressure Gradients in Humans
Authors: Giebler Reiner M. , Behrends Matthias , Steffens Thorsten , Walz Martin K. , Peitgen Klaus , Peters Jürgen 
Published: November 2003

Background
The authors hypothesized that intraperitoneal and retroperitoneal carbon dioxide insufflation during surgical procedures evoke markedly different effects on the venous low-pressure system, induce different inferior caval vein pressure gradients at similar insufflation pressures, and may provide evidence for the Starling resistor concept of abdominal venous return.

Methods
Intra- and extrathoracic caval vein pressures were measured using micromanometers during carbon dioxide insufflation at six cavity pressures (baseline and 10, 15, 20, and 24 mmHg and desufflation) in 20 anesthetized patients undergoing laparoscopic (supine, n = 8) or left (n = 6) or right (n = 6) retroperitoneoscopic (prone position) surgery. Intracavital, esophageal, and gastric pressures also were assessed. Data were analyzed for insufflation pressure-dependent and group effects by one-way and two-way analysis of variance for repeated measurements, respectively, followed by the Newman-Keuls post hoc test (P < 0.05).

Results
Intraperitoneal, unlike retroperitoneal, insufflation markedly increased, in an insufflation pressure-dependent fashion, the inferior-to-superior caval vein pressure gradient (P < 0.00001) at the level of the diaphragm. In contrast to what was observed with retroperitoneal insufflation, transmural intrathoracic caval vein pressure increased at 10 mmHg insufflation pressure, but the increase flattened with an insufflation pressure of more than 10 mmHg, and pressure decreased with an inflation pressure of 20 mmHg (P = 0.0397). These data are consistent with a zone 2 or 3 abdominal vascular condition during intraperitoneal and a zone 3 abdominal vascular condition during retroperitoneal insufflation.

Conclusions
Intraperitoneal but not retroperitoneal carbon dioxide insufflation evokes a transition of the abdominal venous compartment from a zone 3 to a zone 2 condition, presumably impairing venous return, supporting the Starling resistor concept of abdominal venous return in humans.
Acute Severe Isovolemic Anemia Impairs Cognitive Function and Memory in Humans
Authors: Weiskopf Richard B. , Kramer Joel H. , Viele Maurene , Neumann Mireille , Feiner John R. , Watson Jessica J. , Hopf Harriet W. , Toy Pearl 
Published: November 2003

Background
Erythrocytes are transfused to prevent or treat inadequate oxygen delivery resulting from insufficient hemoglobin concentration. Previous studies failed to find evidence of inadequate systemic oxygen delivery at a hemoglobin concentration of 5 g/dl. However, in those studies, sensitive, specific measures of critical organ function were not used. This study tested the hypothesis that acute severe decreases of hemoglobin concentration alters human cognitive function.

Methods
Nine healthy volunteers, age 29 +/- 5 yr (mean +/- SD), were tested with verbal memory and standard, computerized neuropsychologic tests before and after acute isovolemic reduction of their hemoglobin to 7, 6, and 5 g/dl and again after transfusion of their autologous erythrocytes to return their hemoglobin concentration to 7 g/dl. To control for duration of the experiment, each volunteer also completed the same tests on a separate day, without alteration of hemoglobin, at times of the day approximately equivalent to those on the experimental day.

Results
No test showed any change in reaction time or error rate at hemoglobin concentration of 7 g/dl compared with the data at the baseline hemoglobin concentration of 14 g/dl. Reaction time, but not error rate, for horizontal addition and digit-symbol substitution test (DSST) increased at hemoglobin 6 g/dl (mean horizontal addition, 19%; 95% confidence interval [CI], 4-34%; mean DSST, 10%; 95% CI, 4-17%) and further at 5 g/dl (mean horizontal addition, 43%; 95% CI, 6-79%; mean DSST, 18%; 95% CI, 4-31%). Immediate and delayed memory was degraded at hemoglobin 5 g/dl but not at 6 g/dl. Return of hemoglobin to 7 g/dl returned all tests to baseline, except for the DSST, which significantly improved, and returned to baseline the following morning after transfusion of all autologous erythrocytes.

Conclusion
Acute reduction of hemoglobin concentration to 7 g/dl does not produce detectable changes in human cognitive function. Further reduction of hemoglobin level to 6 and 5 g/dl produces subtle, reversible increases in reaction time and impaired immediate and delayed memory. These are the first prospective data to demonstrate subtle degraded human function with acute anemia of hemoglobin concentrations of 6 and 5 g/dl. This reversibility of these decrements with erythrocyte transfusion suggests that our model can be used to test the efficacy of erythrocytes, oxygen therapeutics, or other treatments for acute anemia.
Intravenous Lidocaine Inhibits Visceral Nociceptive Reflexes and Spinal Neurons in the Rat
Authors: Ness Timothy J. 
Published: November 2003

Background
Systemically administered local anesthetics and other sodium channel blockers produce analgesia in patients with hypersensitivity disorders. To assess whether these agents have a role in the treatment of visceral pain, the present study examined the effects of intravenous lidocaine on neuronal and reflex responses to colorectal distension.

Methods
In decerebrate, cervical spinal cord-transected male rats, the lumbosacral spinal cord was exposed by a laminectomy. Dorsal horn neurons demonstrating excitatory responses to colorectal distension were identified using microelectrodes. Sequential doses of lidocaine were administered intravenously. In chronically instrumented, unanesthetized rats, visceromotor responses, pressor responses, and increases in heart rate were elicited by colorectal distension and sequential doses of lidocaine.

Results
Intravenous lidocaine dose-dependently inhibited visceromotor and cardiovascular reflexes and the evoked and spontaneous activity of neurons excited by colorectal distension. There were statistically greater effects on one of the neuronal subgroups (sustained neurons) than on another subgroup (abrupt neurons.)

Conclusions
Intravenous lidocaine had dose-dependent, inhibitory effects on two spinal neuronal populations excited by colorectal distension and dose-dependently inhibited reflex responses to the same stimulus. This suggests there may be utility of sodium channel blockers in the treatment of pain of visceral origin.
Isoflurane, but not Halothane, Induces Protection of Human Myocardium via Adenosine A1Receptors and Adenosine Triphosphate–sensitive Potassium Channels
Authors: Roscoe Amy K. , Christensen Jared D. , Lynch Carl 
Published: November 2003

Background
Volatile anesthetics produce differing degrees of myocardial protection in animal models of ischemia. The purpose of the current investigation was to determine the influence of isoflurane and halothane on myocardial protection in a human model of simulated ischemia and the role of adenosine A1 receptors and adenosine triphosphate-sensitive potassium (KATP) channels in the anesthetic pathway.

Methods
Human atrial trabecular muscles were superfused with oxygenated Krebs-Henseleit buffer and stimulated at 1 Hz, with recording of maximum contractile force. Fifteen minutes before a 30-min anoxic insult, muscles were pretreated for 5 min with either anoxia, the A1 agonist N6-cyclohexyladenosine, 1% halothane or 1.2% isoflurane. These treatments were also performed in the presence of either the KATP channel antagonist glibenclamide or the A1 receptor antagonist 8-cyclopentyl-1,3-dipropylxanthine (DPCPX). Anesthetic effects were also determined on KATP currents in isolated whole cell voltage-clamped human atrial myocytes.

Results
Recovery of force (recorded 60 min after anoxia) in isoflurane-pretreated muscles was reduced from 76.6 +/- 7.5% of baseline to 43.7 +/- 7.1% by pretreatment with glibenclamide, and to 52.5 +/- 6.2% by pretreatment with DPCPX. Halothane treatment provided no cardioprotection and seemed to inhibit protection by anoxic preconditioning. Halothane decreased whole cell KATP currents in atrial myocytes, whereas isoflurane had no effects.

Conclusions
This study demonstrates the cardioprotective effects of isoflurane in contrast to the effects of halothane. Furthermore, A1 receptors and KATP channels seem to mediate the beneficial effects of anoxia and isoflurane in human myocardium.
Sildenafil Is a Pulmonary Vasodilator in Awake Lambs with Acute Pulmonary Hypertension
Authors: Weimann Jörg , Ullrich Roman , Hromi Jonathan , Fujino Yuji , Clark Martin W. H. , Bloch Kenneth D. , Zapol Warren M. 
Published: November 2003

Background
Phosphodiesterase type 5 (PDE5) hydrolyzes cyclic guanosine monophosphate in the lung, thereby modulating nitric oxide (NO)/cyclic guanosine monophosphate-mediated pulmonary vasodilation. Inhibitors of PDE5 have been proposed for the treatment of pulmonary hypertension. In this study, we examined the pulmonary and systemic vasodilator properties of sildenafil, a novel selective PDE5 inhibitor, which has been approved for the treatment of erectile dysfunction.

Methods
In an awake lamb model of acute pulmonary hypertension induced by an intravenous infusion of the thromboxane analog U46619, we measured the effects of 12.5, 25, and 50 mg sildenafil administered via a nasogastric tube on pulmonary and systemic hemodynamics (n = 5). We also compared the effects of sildenafil (n = 7) and zaprinast (n = 5), a second PDE5 inhibitor, on the pulmonary vasodilator effects of 2.5, 10, and 40 parts per million inhaled NO. Finally, we examined the effect of infusing intravenous l-NAME (an inhibitor of endogenous NO production) on pulmonary vasodilation induced by 50 mg sildenafil (n = 6).

Results
Cumulative doses of sildenafil (12.5, 25, and 50 mg) decreased the pulmonary artery pressure 21%, 28%, and 42%, respectively, and the pulmonary vascular resistance 19%, 23%, and 45%, respectively. Systemic arterial pressure decreased 12% only after the maximum cumulative sildenafil dose. Neither sildenafil nor zaprinast augmented the ability of inhaled NO to dilate the pulmonary vasculature. Zaprinast, but not sildenafil, markedly prolonged the duration of pulmonary vasodilation after NO inhalation was discontinued. Infusion of l-NAME abolished sildenafil-induced pulmonary vasodilation.

Conclusions
Sildenafil is a selective pulmonary vasodilator in an ovine model of acute pulmonary hypertension. Sildenafil induces pulmonary vasodilation via a NO-dependent mechanism. In contrast to zaprinast, sildenafil did not prolong the pulmonary vasodilator action of inhaled NO.
Acute Ethanol Treatment Modulates δ Opioid Receptors in N18TG2 Cells
Authors: Gomes Ivone , Trapaidze Nino , Turndorf Herman , Devi Lakshmi Arehole , Bansinath Mylarrao 
Published: November 2003

Background
The in vitro adaptive responses of delta opiate receptors (DOR) to chronic ethanol treatment have been well documented. The acute effects of ethanol on these receptors are not well characterized beyond its effect on ligand binding. The aim of this study was to evaluate the acute effects of clinically relevant concentrations of ethanol (50-200 mm) on the saturation binding kinetics, receptor/ligand internalization, and agonist stimulation of G-protein coupling in N18TG2 cells expressing the Flag epitope-tagged mouse DOR.

Methods
Confocal microscopy was used to localize Flag epitope-tagged DOR in N18TG2 cells. Saturation binding assays at 4 degrees C and 37 degrees C were conducted in the absence or presence of ethanol on cells not pretreated or pretreated with ethanol for 30 min at 37 degrees C. Highly specific delta agonist, DPDPE ([D-Pen2,D-Pen5]enkephalin), was used in these studies. The effect of ethanol on agonist stimulation of G-protein coupling was examined using [35S]GTPgammaS (guanosine-5'-O-(3-thio)triphosphate) binding to membranes. Agonist-mediated receptor internalization was examined using flow cytometry of cells labeled with the antiserum directed against the Flag epitope, and the ligand internalization was examined using [3H]DPDPE.

Results
Ethanol decreased the binding of the agonist [3H]DPDPE, and not the antagonist [3H]diprenorphine, in a dose-dependent manner. These effects were temperature-dependent. Ethanol reversibly inhibited agonist stimulation of [35S]GTPgammaS binding. In non-pretreated cells, ethanol decreased the rate of receptor/ligand internalization, but this effect was not seen in ethanol pretreated cells. Taken together, these results suggest that pretreatment of N18TG2 cells with ethanol induces compensatory mechanisms that allow the receptor to function efficiently in its presence.

Conclusion
Acute ethanol decreased the binding, agonist-mediated functional coupling and receptor/ligand internalization in N18TG2 cells expressing epitope-tagged DOR. In these cells, 30-min pretreatment with ethanol was sufficient to reverse these effects.
Pharyngolaryngeal, Neck, and Jaw Discomfort after Anesthesia with the Face Mask and Laryngeal Mask Airway at High and Low Cuff Volumes in Males and Females
Authors: Brimacombe Joseph , Holyoake Lindsey , Keller Christian , Brimacombe Nick , Scully Miriam , Barry John , Talbutt Paul , Sartain James , McMahon Paul 
Published: November 2003

Background
There is controversy over (1) the relative incidence of sore throat between the face mask (FM) and laryngeal mask airway (LMA), (2) the efficacy of LMA intracuff pressure reduction as a mechanism for minimizing sore throat, and (3) the relative incidence of sore throat with the LMA between males and females. In a randomized double-blind study, the authors compared laryngopharyngeal, neck, and jaw discomfort with the FM and LMA at high and low cuff volumes in males and females.

Methods
Three hundred adult patients were randomly assigned to three equal-sized groups for airway management: (1) the FM, (2) the LMA with a fully inflated cuff (LMA-High), or (3) the LMA with a semi-inflated cuff (LMA-Low). Anesthesia was administered with propofol, nitrous oxide, oxygen, and isoflurane. In the FM group, a Guedel-type oropharyngeal airway and jaw thrust were used only if necessary. In the LMA groups, cuff inflation was achieved with either 15 or 30 ml for the size 4 (females) and 20 or 40 ml for the size 5 (males). The LMA was removed when the patient was awake. Patients were questioned 18-24 h postoperatively about surgical pain, sore throat, sore neck, sore jaw, dysphonia, and dysphagia, and about whether they were satisfied with their anesthetic.

Results
The incidence of sore throat was lower in the FM (8%) than the LMA-High (42%) and LMA-Low (20%) groups (both: P < or = 0.02). The incidence of sore neck was higher for the FM (14%) than the LMA-High group (6%; P = 0.05) but similar to the LMA-Low group (8%). The incidence of sore jaw was higher in the FM (11%) than the LMA-High (3%) and LMA-Low (3%) groups (both: P = 0. 02). There were no differences among groups for surgical pain or dysphonia. The incidence of dysphagia was lower in the FM (1%) than the LMA-High group (11%; P = 0.003), but similar to the LMA-Low group (1%). The incidence of sore throat and dysphagia was lower in the LMA-Low group than the LMA-High group for both males and females (all: P < or = 0.04). There were no differences in discomfort levels between males and females in any group. Two patients from the FM group and one from the LMA-High group were not satisfied with their anesthetic. These complaints were unrelated to postoperative morbidity.

Conclusion
The LMA causes more sore throat and dysphagia but less jaw pain than the FM. Sore throat and dysphagia are more common with the LMA if the initial cuff volume is high. There are no differences in discomfort levels between males and females. However, these discomforts do not influence patient satisfaction after LMA or FM anesthesia.