bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Self-inflating Bulb to Detect Esophageal Intubation during Emergency Airway Management
Authors: Kasper Carol L. , Deem Steven 
Published: November 2003

Background
The negative-pressure test using a self-inflating bulb (SIB) during emergency intubation was studied to determine its reliability and predictive value in this setting.

Methods
The endotracheal tube (ETT) position was tested in 300 consecutive patients undergoing in-hospital emergency endotracheal intubation. Immediately after intubation and before ETT cuff inflation, the following protocol was strictly followed: (1) an SIB was compressed, connected to the ETT, and released. A 10-s period was allowed for the bulb to inflate. (2) The ETT cuff was inflated, and the ETT position was confirmed using colorimetric or infrared carbon dioxide detection, or both, combined with clinical evaluation.

Results
There were 19 esophageal intubations (6% incidence). The SIB correctly identified all patients with esophageal intubation (sensitivity, 100%) and correctly identified all but three ETTs placed in the trachea (specificity, 99%). The three tracheally placed tubes that were misidentified by the bulb syringe occurred during one case each of chronic obstructive pulmonary disease, copious secretions, and obesity; of note were three tracheally placed tubes that were misidentified by the carbon dioxide analyzers during cardiopulmonary resuscitation.

Conclusions
The SIB proved to be a sensitive and specific test for esophageal intubation in the emergency setting when used according to the protocol described, and it is complementary to carbon dioxide detection. The predictive value of the bulb syringe appears to be improved when a prolonged period for reinflation is allowed. It holds particular promise because of its low cost and portability.
Sex-related Differences in the Influence of Morphine on Ventilatory Control in Humans
Authors: Dahan Albert MD , Sarton Elise , Teppema Luc , Olievier Cees 
Published: November 2003

Background
Opiate agonists have different analgesic effects in male and female patients. The authors describe the influence of sex on the respiratory pharmacology of the mu-receptor agonist morphine.

Methods
The study was placebo-controlled, double-blind, and randomized. Steady-state ventilatory responses to carbon dioxide and responses to a step into hypoxia (duration, 3 min; oxygen saturation, approximately 82%; end-tidal carbon dioxide tension, 45 mmHg) were obtained before and during intravenous morphine or placebo administration (bolus dose of 100 microg/kg, followed by a continuous infusion of 30 microg x kg(-1) x h(-1)) in 12 men and 12 women.

Results
In women, morphine reduced the slope of the ventilatory response to carbon dioxide from 1.8 +/- 0.9 to 1.3 +/- 0.7 l x min(-1) x mmHg(-1) (mean +/- SD; P < 0.05), whereas in men there was no significant effect (control = 2.0 +/- 0.4 vs. morphine = 1.8 +/- 0.4 l x min(-1) x mmHg(-1)). Morphine had no effect on the apneic threshold in women (control = 33.8 +/- 3.8 vs. morphine = 35.3 +/- 5.3 mmHg), but caused an increase in men from 34.5 +/- 2.3 to 38.3 +/- 3 mmHg, P < 0.05). Morphine decreased hypoxic sensitivity in women from 1.0 +/- 0.5 l x min(-1) x %(-1) to 0.5 +/- 0.4 l x min(-1) x %(-1) (P < 0.05) but did not cause a decrease in men (control = 1.0 +/- 0.5 l x min(-1) x %(-1) vs. morphine = 0.9 +/- 0.5 l x min(-1) x %(-1)). Weight, lean body mass, body surface area, and calculated fat mass differed between the sexes, but their inclusion in the analysis as a covariate revealed no influence on the differences between men and women in morphine-induced changes.

Conclusions
In both sexes, morphine affects ventilatory control. However, we observed quantitative and qualitative differences between men and women in the way morphine affected the ventilatory responses to carbon dioxide and oxygen. Possible mechanisms for the observed sex differences in the respiratory pharmacology of morphine are discussed.
Awakening Propofol Concentration with and without Blood-Effect Site Equilibration after Short-term and Long-term Administration of Propofol and Fentanyl Anesthesia
Authors: Kazama Tomiei , Ikeda Kazuyuki , Morita Koji , Sanjo Yoshimitsu 
Published: November 2003

Background
The propofol awakening concentration can vary. However, the effect site awakening propofol concentration will be a fixed value. The purpose of this study was to determine the awakening propofol concentrations obtained from infusion Schede using abrupt discontinuation of propofol (half-maximal effective concentration [EC50]) or a descending decrease in concentration to allow blood-effect site equilibration (EC50eq).

Methods
Patients undergoing short-term (group 1) and long-term (group 2) elective surgery were anesthetized with computer-assisted continuous infusion of propofol and fentanyl, with both groups receiving the same propofol (3 microg/ml) and fentanyl (1 ng/ml) concentrations 20-30 min before the end of surgery until the end. Then both groups were further divided into two subgroups: subgroup A abrupt discontinuation, and subgroup B descending concentrations of propofol (15-min duration per concentration). In the A subgroups, the response to verbal command was evaluated every 30 s. In the B subgroups, the blood propofol concentrations just permitting and just preventing response to command were averaged individually. The EC50 and EC50eq values were determined by probit analysis.

Results
The EC50 of group 1A was 1 microg/ml, which was significantly less than the 1.6 microg/ml of group 2A (P < 0.05). The awakening time of group 1A was 5.2 +/- 1.8 min, which was significantly shorter than the 9.3 +/- 3.5 min of group 2A (means +/- SD). The EC50eq of both groups 1B and 2B was 2.2 microg/ml.

Conclusions
The EC50eq was independent of propofol infusion length, compared with the EC50. Thus the potential for hysteresis during emergence from propofol anesthesia was confirmed.
Open-lung Biopsy in Patients with Acute Respiratory Distress Syndrome
Authors: Papazian Laurent , Thomas Pascal , Bregeon Fabienne , Garbe Louise , Zandotti Christine , Saux Pierre , Gaillat Francoise , Drancourt Michel , Auffray Jean-Pierre , Gouin Francois 
Published: November 2003

Background
It has been suggested that fibrosis present during the fibroproliferative phase of acute respiratory distress syndrome (ARDS) can be treated by corticosteroids. However, neither clinical nor microbiologic criteria permit differentiation of this fibroproliferative phase from a nosocomial pneumonia. The aim of this observational case series was to evaluate the safety and utility of open-lung biopsy (OLB) performed in patients receiving ventilatory support who had persistent ARDS despite negative bacterial cultures.

Methods
During a 4-yr period, 37 OLBs were performed in 36 of 197 patients receiving ventilatory support who had ARDS. The severity of ARDS was assessed by a lung injury score of 3.1 +/- 0.4 (mean +/- SD) and a median ratio of the partial pressure of oxygen (PaO2) to the fraction of inspired oxygen (FiO2) of 118 mmHg. Histologic examination; bacterial, fungal, and acid-fast staining; and cultures of the tissue sample were performed.

Results
Fibrosis was present in only 41% of the lung specimens obtained by OLB. Only six patients received corticosteroids (17%). In 9 of the 15 patients with fibrosis, cytomegalovirus pneumonia precluded the use of corticosteroids. Histologic cytomegalovirus pneumonia was diagnosed in 18 cases. Histologic bacterial or mycobacterial pneumonia was diagnosed in five cases. No significant change in arterial blood gases was noted as linked to the biopsy procedure except an increase of the PaO2/FiO2 ratio. One pneumothorax was diagnosed on a chest roentgenogram 12 h after OLB. Only one patient required blood transfusion during the 48-h period after OLB (for an hemothorax). Five patients had moderate air leaks from operative chest tubes for 2-10 days.

Conclusions
Open lung biopsy appeared to be a useful and acceptably safe diagnostic technique in patients with ARDS. It permitted the diagnosis of unexpected cytomegalovirus pneumonia.
The Effect of the Reduction of Colloid Reduction of Oncotic Pressure, with and without Reduction of Osmolality, on Post-traumatic Cerebral Edema
Authors: Drummond John C. , Patel Piyush M. , Cole Daniel J. , Kelly Paul J. 
Published: November 2003

Background
It has been asserted that reduction of colloid oncotic pressure (COP) can aggravate traumatic brain edema. To explore this issue, the authors measured the effect of COP reduction, with and without a simultaneous decrease in osmolality, on the development of brain edema after fluid percussion injury (FPI).

Methods
Isoflurane-anesthetized Wistar rats received a 2.7-atm right parasagittal FPI followed by isovolemic exchange with (1) normal saline (NS); (2) half-normal saline (0.5 NS); (3) whole blood (WB); or (4) hetastarch (Hespan, Dupont). Shed blood (16 ml) was replaced with donor erythrocytes suspended in the study fluid. The WB group received heparinized fresh donor WB. Central venous pressure was maintained with additional study fluid as required. The specific gravity (SG) of the cortex and subcortex near the impact site was determined 4.5 h after FPI. The water content of the hemispheres was also determined using the wet-dry method. To define the status of the blood-brain barrier in the non-FPI hemisphere, two additional groups (FPI, non-FPI) were studied. Both groups received 30 mg/kg Evans' blue and NS at 4 ml/kg(-1)/h(-1). Four hours after FPI, the concentration of Evans' blue in the hemispheres was determined.

Results
After exchange, COP (mmHg +/- SD) decreased in the NS (9.6 +/- 2.1) and 0.5 NS (8.5 +/- 0.5) groups and was unchanged in the WB (16.7 +/- 3.3) and hetastarch (18.9 +/- 1.1) groups. Osmolality was unchanged in the WB group (295 +/- 5 mOsm/kg), increased in the NS (304 +/- 3 mOsm/kg) and hetastarch (306 +/- 2 mOsm/kg) groups, and was decreased in the 0.5 NS group (261 +/- 6 mOsm/kg). The Evans' blue data indicated that FPI resulted in blood-brain barrier damage in both hemispheres. In all four exchange groups, the SG of both cortical and subcortical tissue was less (indicating greater water content) in the impact hemisphere than in the nonimpact hemisphere. The SG was less in both hemispheres, although it was less in both hemispheres in the NS and 0.5 NS groups than in the WB and hetastarch groups. The lowest SG values were observed in the 0.5 NS group. The wet-dry water content determinations yielded a similar pattern of edema formation.

Conclusions
These data, while confirming the important edematogenic effect of decreased osmolality, indicate that COP reduction per se can also aggravate brain edema after a mild to moderate mechanical head injury.
Pulmonary Vasodilator Response to Adenosine Triphosphate-Sensitive Potassium Channel Activation Is Attenuated during Desflurane but Preserved during Sevoflurane Anesthesia Compared with the Conscious State
Authors: Nakayama Masayasu , Kondo Uruo , Murray Paul A. 
Published: November 2003

Background
The objective of this study was to investigate the effects of sevoflurane and desflurane anesthesia on the pulmonary vasodilator response to the adenosine triphosphate-sensitive potassium channel agonist, lemakalim, compared with the response measured in the conscious state. In addition, the authors assessed the extent to which sympathetic alpha1-adrenoreceptor inhibition and cyclooxygenase pathway inhibition modulate the vasodilator response to lemakalim.

Methods
Twenty-four conditioned male mongrel dogs were chronically instrumented to measure the left pulmonary vascular pressure-flow relationship. After preconstriction with the thromboxane analogue, U46619, dose-response relationships to lemakalim were assessed on separate days in the conscious state and during sevoflurane (approximately 3.5% end-tidal) and desflurane (approximately 10.5% end-tidal) anesthesia (approximately 1.5 minimum alveolar concentration for each anesthetic agent). The effects of sympathetic alpha1-adrenoreceptor inhibition (prazosin) and cyclooxygenase inhibition (indomethacin) on the pulmonary vasodilator response to lemakalim also were assessed in the conscious and desflurane-anesthetized states.

Results
Neither sevoflurane nor desflurane had a net effect on the baseline left pulmonary vascular pressure-flow relationship compared with the conscious state. The magnitude of the pulmonary vasodilator response to lemakalim was preserved during sevoflurane anesthesia but was attenuated (P < 0.05) during desflurane anesthesia compared with the conscious state. The attenuated lemakalim-induced vasodilator response during desflurane anesthesia was partially reversed (P < 0.05) by pretreatment with prazosin but not indomethacin.

Conclusion
These results indicate that adenosine triphosphate-sensitive potassium channel-mediated pulmonary vasodilation is preserved during sevoflurane anesthesia but is attenuated during desflurane anesthesia. The attenuated response to adenosine triphosphate-sensitive potassium channel activation during desflurane anesthesia is partially mediated by reflex sympathetic alpha1-adrenoreceptor vasoconstriction.
Effect of Subarachnoid Bupivacaine Block on Anesthetic Requirements for Thiopental in Rats
Authors: Eappen Sunil , Kissin Igor 
Published: November 2003

Background
Subarachnoid bupivacaine blockade has been reported to reduce thiopental and midazolam hypnotic requirements in patients. The purpose of this study was to examine if local anesthetically induced lumbar intrathecal blockade would reduce thiopental requirements for blockade of motor responses to noxious and nonnoxious stimuli in rats.

Methods
After intrathecal and external jugular catheter placement, rats were assigned randomly to two groups in a crossover design study, with each rat to receive either 10 microl of 0.75% bupivacaine or 10 microl of normal saline intrathecally. The doses of intravenously administered thiopental required to ablate the eyelid reflex, to block the withdrawal reflex of a front limb digit, and to block the corneal reflex were compared. In two separate groups of animals, hemodynamic parameters and concentrations of thiopental in the brain were compared between intrathecally administered bupivacaine and saline.

Results
The thiopental dose required to block the described responses was decreased with intrathecally administered bupivacaine versus intrathecally administered saline from (mean +/- SD) 40 +/- 5 to 24 +/- 4 mg/kg (P < 0.001) for the eyelid reflex, from 51 +/- 6 to 29 +/- 6 mg/kg (P < 0.005) for front limb withdrawal, and from 67 +/- 8 to 46 +/- 8 mg/kg (P < 0.01) for the corneal reflex. The concentration of thiopental in the brain at the time of corneal reflex blockade for the group given bupivacaine was significantly lower than in the group given saline (24.1 vs. 35.8 microg/g, P = 0.02).

Conclusion
This study demonstrates that lumbar intrathecally administered local anesthetic blockade decreases anesthetic requirements for thiopental for a spectrum of end points tested. This effect is due neither to altered pharmacokinetics nor to a direct action of the local anesthetic on the brain; rather, it is most likely due to decreased afferent input.
Interaction of Isoflurane and Sevoflurane with α- and β-adrenoceptor Stimulations in Rat Myocardium
Authors: Hanouz Jean-Luc , Gueugniaud Pierre-Yves , Lecarpentier Yves , Coriat Pierre , Riou Bruno 
Published: November 2003

Background
Halothane potentiates the positive inotropic effects of alpha- and beta-adrenoceptor stimulations but impairs the positive lusitropic effect of beta-adrenoceptor stimulations. However, the interactions of isoflurane and sevoflurane with alpha- and beta-adrenoceptor stimulation have not been entirely defined.

Methods
The effects of 1 minimum alveolar concentration isoflurane and sevoflurane on the inotropic responses induced by phenylephrine (10(-8) to 10(-4) M) or isoproterenol (10(-8 to 10(-4) M) were studied in rat left ventricular papillary muscles in vitro (Krebs-Henseleit solution, 29 degrees C; pH, 7.4; 0.5 mM calcium; stimulation frequency, 12 pulses/min). The positive lusitropic effects of alpha- and beta-adrenoceptor stimulations were studied under isotonic and isometric conditions. Data are mean percentages of baseline +/- SEM.

Results
In control groups, phenylephrine (134 +/- 8%; P < 0.05) and isoproterenol (171 +/- 7%; P < 0.05) induced a positive inotropic effect. Isoflurane enhanced the positive inotropic effects of phenylephrine (185 +/- 10%; P < 0.05) and of isoproterenol (203 +/- 11%; P < 0.05). Sevoflurane enhanced the positive inotropic effects of phenylephrine (187 +/- 10%; P < 0.05) and of isoproterenol (228 +/- 11%; P < 0.05). These potentiations were similar to those previously reported with halothane. Isoflurane and sevoflurane did not modify the positive lusitropic effects under low and high loads of isoproterenol.

Conclusion
Although isoflurane and sevoflurane have moderate negative inotropic effects, they potentiated the positive inotropic effects of alpha- and beta-adrenoceptor stimulations but did not modify the positive lusitropic effects of beta-adrenoceptor stimulation.
Proarrhythmic and Antiarrhythmic Effects of Bupivacaine in an In Vitro Model of Myocardial Ischemia and Reperfusion
Authors: Picard Sandra , Rouet Rene , Flais Frederic , Ducouret Pierre , Babatasi Gerard , Khayat Andre , Potier Jean-Claude , Bricard Henri , Gerard Jean-Louis 
Published: November 2003

Background
Bupivacaine may have toxic cardiovascular effects when accidentally administered by intravascular injection. However, its electrophysiologic effects in the presence of myocardial ischemia remain unknown. The authors evaluated the electrophysiologic and anti- and proarrhythmic effects of bupivacaine in an in vitro model of the ischemic and reperfused myocardium.

Methods
In a double-chamber bath, a guinea pig right ventricular muscle strip was subjected partly to normal conditions and partly to simulated ischemia followed by reperfusion. The electrophysiologic effects of bupivacaine were studied at 1, 5, and 10 microM concentrations.

Results
Bupivacaine (5 and 10 microM) decreased the maximal upstroke velocity of the action potential (Vmax) in normoxic conditions and further decreased (10 microM) the Vmax decrease induced by ischemic conditions. Bupivacaine reduced the mean occurrence time to the onset of myocardial conduction blocks (9 +/- 3 min; mean +/- SD; P < 0.005 with 5 and 10 microM, compared with 17 +/- 6 min during simulated ischemia with no drug or control), and it increased the number of preparations that became inexcitable to pacing (55% of preparations, with 1 microM and 100% with 5 and 10 microM, compared with 17% for the control group). The incidence of spontaneous arrhythmias was reduced by 5 and 10 microM bupivacaine during ischemia and reperfusion and was enhanced by 1 microM bupivacaine during the ischemic phase.

Conclusions
In guinea pig myocardium under ischemic conditions, bupivacaine induced a loss of excitability at concentrations of 5 and 10 microM. Proarrhythmic effects observed at 1 microM were considered as lower than the cardiotoxic range in normoxic conditions. The incidence of reperfusion arrhythmias was decreased at all concentrations.
Intravenous Remifentanil
Authors: Kan Randall E. , Hughes Samuel C. , Rosen Mark A. , Kessin Charlize , Preston Paul G. , Lobo Errol P. 
Published: November 2003

Background
Remifentanil has not been studied in obstetric patients. This study evaluates the placental transfer of remifentanil and the neonatal effects when administered as an intravenous infusion.

Methods
Nineteen parturients underwent nonemergent cesarean section with epidural anesthesia and received 0.1 microg kg(-1) x min(-1) remifentanil intravenously, which was continued until skin closure. Maternal arterial (MA), umbilical arterial (UA), and umbilical venous (UV) blood samples were obtained at delivery for analysis of drug concentrations of remifentanil, its metabolite, and blood gases. Maternal vital signs were monitored continuously, and pain and sedation levels were assessed intermittently. Apgar scores were obtained at 1, 5, 10, and 20 min, and Neonatal and Adaptive Capacity Scores were noted 30 and 60 min after delivery. Parturients and newborns were observed for at least 24 h after surgery for side effects.

Results
The means and SDs of UV:MA and UA:UV ratios for remifentanil were 0.88+/-0.78 and 0.29+/-0.07, respectively. Mean clearance was 93 ml x min(-1) kg(-1). The mean UV:MA and UA:MV ratios for remifentanil acid were 0.56+/-0.29 and 1.23+/-0.89, respectively. The mean MA (remifentanil acid):MA (remifentanil) ratio was 2.92+/-3.65. There were no adverse effects on the neonates, but there was a sedative effect and respiratory depressant effect on the mothers.

Conclusions
Remifentanil crosses the placenta but appears to be rapidly metabolized, redistributed, or both. Maternal sedation and respiratory changes occur, but without adverse neonatal or maternal effects.
A Comparison of the Posterior versus Lateral Approaches to the Block of the Sciatic Nerve in the Popliteal Fossa
Authors: Hadzic Admir , Vloka Jerry D. 
Published: November 2003

Background
The main disadvantage of the posterior approach to the block of the sciatic nerve in the popliteal fossa (popliteal block [PB]) is the need to place the patient in the prone position. In this study, the authors examined the clinical utility of a recently described lateral approach to PB that is performed with the patient in the supine position, and they compared its ability to provide reliable surgical anesthesia with that of the posterior approach.

Methods
Fifty patients undergoing surgery of a lower extremity were randomized to receive the PB using either the lateral (n=25) or the posterior approach (n=25). With both techniques, 40 ml 1.5% alkalinized mepivacaine with 1:200,000 epinephrine were injected on successful nerve localization using low current output nerve stimulation.

Results
There were no differences in American Society of Anesthesiologists physical status or demographic data between the groups (ASA status, I-III; mean age, 50+/-15 yr; 27 men, 23 women). All patients had good intraoperative analgesia, except one in the lateral group, who reported pain outside the distribution of the sciatic nerve.

Conclusions
Although blockade using the lateral approach took longer to accomplish, both techniques resulted in clinically acceptable anesthesia in the distribution of the sciatic nerve.