bluuebunny/crossref_metadata_2025_split huggingface dataset:
Expiratory flow‐volume curves in mechanically ventilated patients with chronic obstructive pulmonary disease
Authors: Aerts J. G. J. V. , Van Den Berg B. , Lourens M. S. , Bogaard J. M. 
Published: March 2003

Background: Forced expiratory flow‐volume curves are commonly used to assess the degree of airflow obstruction in patients with chronic obstructive pulmonary disease (COPD). In mechanically ventilated subjects, expiratory airways obstruction can only be estimated from relaxed expirations. The aim of this study was to quantify the degree of airways obstruction from relaxed expiratory flow‐volume curves in mechanically ventilated patients with COPD.Methods: As measure of airflow obstruction, the effective time constant during the last 50% of expired volume (τ) was calculated. For bedside monitoring, τ was recalculated as the slope of the flow during the last 50% of expired volume (SF50). In order to study reproducibility, the variables were calculated from consecutive breaths and at different levels of end‐expiratory lung volume (EEV). The SF50 and the τ were correlated with the forced expiratory volume in 1 s (FEV1) measured prior to the start of ventilatory support.Results: Twenty‐seven patients were studied with a FEV1 expressed as percentage predicted of 31±12% (mean±SD). The SF50 amounted to 19±10°. A positive linear correlation was established between SF50 and the FEV1, (%pred), (r=0.90, P<0.0001). The τ showed an exponential relationship with FEV1 (%pred), (r2=0.78) From 5 consecutive breaths the mean variation coefficient of SF50 was 5±2%. Changes of ΔEEV from 0.05 to 1.00 L did not affect the SF50‐values. In 12 patients, mechanically ventilated for respiratory diseases other than COPD, mean τ and SF50 were significantly different from the COPD‐patients (P<0.0001).Conclusions: This study indicates that relaxed expiratory flow‐volume curves can be used to assess airflow obstruction in mechanically ventilated patients with COPD. This information can be used to adapt ventilatory settings.
Venous gas embolism: Detection with pulsed Doppler guided by two‐dimensional echocardiography
Authors: Boussuges A. , Molenat F. , Carturan D. , Gerbeaux P. , Sainty J. M. 
Published: March 2003

Background: Venous gas embolism is a rare but severe event in critically ill patients and the diagnosis should be obtained as soon as possible. Ultrasonography is a sensitive, non‐invasive, and bedside means of detection.Method: We prospectively estimated the performance of two‐dimensional (2D) echocardiography and pulsed Doppler guided by 2D echocardiography in the detection of venous embolism. We used, as a model of venous gas embolism, the decompression following a recreational dive. This activity is responsible for circulating bubbles related to nitrogen desaturation.Results: Venous gas emboli were detected following 44 of 68 dives in 20 of 24 divers. Gas emboli in 36 cases (16 divers) was shown by 2D echocardiography. Parasternal short‐axis and right‐cavity longitudinal views were the best views for positive detection. Pulsed Doppler confirmed the existence of venous gas emboli in all of the 36 cases with positive detection by 2D echocardiography. In 8 other cases, pulsed Doppler detected circulating bubbles, which were not observed by using 2D echocardiography. Discrepancies were observed in 4 divers with an echographic image of medium or poor quality.Conclusion: Combined utilization of 2D echocardiography and pulsed Doppler provides a better method for the detection of venous gas embolism than 2D echocardiography alone. This protocol could be used for critically ill patients suspected of venous air embolism.
Influence of temperature on tracheal tube cuff pressure during cardiac surgery
Authors: Souza Neto E. P. , Piriou V. , Durand P. G. , George M. , Evans R. , Obadia J. F. , J. Lehot J. 
Published: March 2003

Background: Lateral wall pressure may cause tracheal injury by affecting tracheal capillary blood flow. Damage to the trachea is less severe when lateral wall pressure exerted by the endotracheal tube cuff does not exceed the mean capillary perfusion pressure of the mucosa. The purpose of this study was to determine the effects of hypothermic and normothermic cardiopulmonary bypass (CPB) on tracheal tube cuff pressure dynamics.Methods: Twenty‐two patients were studied during normothermic CPB (pulmonary artery blood temperature in the CPB period between 36 and 35°C), and 22 patients during hypothermic CPB (pulmonary artery temperature in the CPB period between 32 and 28°C). A Mallinckrodt Medical Lo‐ContourTM Murphy tracheal tube, with high‐volume, low‐pressure cuff was used without lubricant. Intracuff pressure (ITCP) was recorded at end‐expiration before, during and after cardiopulmonary bypass.Results: ITCP measurements were different between groups during CPB at aortic cross‐clamping (13.9±0.8 mmHg in the normothermic group versus 11.3±0.4 mmHg in the hypothermic group, P<0.05), and respectively during CPB after aortic declamping (15.3±0.8 mmHg and 12.6±0.8 mmHg, P<0.05) and after CPB at the end of surgery (16.8±0.7 mmHg and 18.6±0.3 mmHg, P<0.05).Conclusion: We conclude that the ITCP is higher in normothermic CPB than in hypothermic CPB; however, the clinical significance of this observation needs further investigation.
Effects of small peripheral temperature changes on the evoked baseline electromyographic response
Authors: Santanen O. A. P. , Paloheimo M. P. J. 
Published: March 2003

Background: Since muscle temperature seems to influence the electrically evoked compound muscle action potentials, we wanted to quantificate the effect of light external cooling and warming on evoked responses in a clinical setting.Methods: In ophthalmic surgical patients (ASA I–III), evoked electromyographic (EMG) responses to supramaximal train‐of‐four stimuli were measured once a minute. After obtaining an initial baseline (100%) where temperatures of the first dorsal interosseal muscle and the skin above it had stabilised, the patients’ hands were cooled to stable temperatures by a blower (room air). A new baseline was established and, subsequently, the hand re‐warmed to the starting temperature. The cooling procedure was repeated, operation time allowing.Results: The mean (range) muscle and skin temperature changes were from 36.0°C (35.5–37.1) to 34.6°C (33.2–36.1) and 35.7°C (35.0–36.7) to 32.0°C (29.4–35.6), respectively. The mean (range) change of the EMG‐response was 8.0%/°C (0.3–16.5) for the muscle and 4.1%/°C (0.3–37.9) for the skin. Wide individual variability was evident.Conclusion: The electrically evoked EMG‐response is sensitive to even small changes in temperature at the measurement site. Therefore, when applying the evoked EMG in neuromuscular studies, peripheral skin or muscle temperatures need to be monitored, and attempts to stabilise the temperature of the monitored muscles should be made.
One‐lung ventilation when intubation is difficult – presentation of a new endobronchial blocker
Authors: Arndt G. A. , Delessio S. T. , Kranner P. W. , Orzepowski W. , Ceranski B. , Valtysson B. 
Published: March 2003

Background: One‐lung ventilation utilizing a double‐lumen endotracheal tube may be technically difficult or inappropriate in morbidly obese or critically ill patients. In patients requiring awake fiberoptic intubation, double‐lumen tube placement may be impossible. Wire‐guided endobronchial blockade through a conventional endotracheal tube is a new alternative for these patients.Methods: A 44‐year‐old, 133 kg female patient was scheduled to undergo a thoracotomy for transthoracic fundoplication. A wire‐guided endobronchial blocker (WEB) was placed following rapid‐sequence induction and intubation with an 8.0 OD single‐lumen endotracheal tube with the aid of a pediatric bronchoscope.Results: The WEB, using a guiding loop, was placed with ease and allowed effective one‐lung ventilation.Conclusion: The WEB system allows one‐lung ventilation to be achieved with a conventional endotracheal tube. The need for reintubation at the end of surgery is eliminated and endotracheal tube cross‐sectional area is conserved.
Pharmacokinetics of eltanolone in male and female patients following intravenous bolus injection
Authors: Dale O. , Hynne H. , Parivar K. , Johansson E. , Widman M. 
Published: March 2003

Background: The pharmacokinetics of the steroid anesthetic eltanolone have been studied in male volunteers. However, steroids may exhibit gender‐related differences in pharmacokinetics and surgery may alter drug disposition.Methods: Male (n=12) and female (n=9) ASA 1–2 patients (age 26–45 yrs) undergoing discectomy with microsurgical technique were included. Anesthesia was induced with eltanolone 0.75 mg/kg and maintained with nitrous oxide, fentanyl and atracurium. Venous blood was sampled for up to 12 h and analyzed for eltanolone and its major metabolites.Results: Induction was smooth and anesthesia uneventful, except that five cases developed a mild transient erythema. Loss of verbal contact occurred within 20–60 s. Pharmacokinetics in one person deviated significantly from the rest of the subjects. No difference between groups with respect to the primary outcome variable noncompartmental clearance (Cl, 1/min) 1.7 vs 1.6, was found. However, the volume of distribution at steady state (Vss, l/kg) was larger in women (3.1) compared to men (1.3). The pharmacokinetics followed a three‐compartment model. The half‐lives (min) of the α, β and γ phases (men vs women, medians) were 1.5 vs 2.2, 42 vs 40 and 222 vs 360, respectively. Area under the curve (AUC, min μg/l) was 39810 vs 34905. Context‐sensitive modelling indicated that it may take 10 min more for women than men to recover from an eltanolone infusion of 2 h duration.Conclusion: The gender‐related differences in the pharmacokinetics of eltanolone were small, and of little clinical significance for induction of anesthesia with eltanolone.
Metabolic regulation of cardiac output during inhalation anaesthesia in dogs
Authors: Scheeren T. W. L. , Schwarte L. A. , Arndt J. O. 
Published: March 2003

Background: The metabolic regulation of tissue blood flow manifests itself in a linear relation between blood flow and oxygen consumption, the latter being the independent variable. It is unknown, however, if this fundamental physiological principle operates also during inhalation anaesthesia known to be associated with decreases in both cardiac output (Q˙) and oxygen consumption (V˙O2).Methods: Seven dogs (23–32 kg) with chronically implanted flow probes around the pulmonary artery were repeatedly anaesthetized with halothane, enflurane, isoflurane, sevoflurane, and desflurane at increasing minimum alveolar concentrations (1–3 MAC). Cardiac output (ultrasound transit‐time flowmeter) and V˙O2 (indirect calorimetry) were measured continuously. We also imposed selective changes in Q˙, and thus of O2 supply, to see if and to what extent this would alter V˙O2 during anaesthesia (1.5 MAC).Results: In awake dogs under basal metabolic conditions, V˙O2 was 4.6±0.1 ml · kg−1 · min−1 and Q˙ 105±3 ml · kg−1 · min−1 (mean±SEM). During inhalation anaesthesia, V˙O2 and Q˙ decreased by approximately 30% and 60%, respectively. The concentration‐effect relations of both variables did not differ between anaesthetics, yielding a uniform Q˙/V˙O2 relation, which was nearly linear in the range (0–2 MAC) with an average slope of 39±1 (range 30–55). Above 2 MAC, Q˙ decreased more for a given change in V˙O2, and O2 extraction increased by 50%, indicating compromised oxygen delivery (D˙O2). Imposed changes in Q˙, both in awake and anaesthetized dogs, yielded Q˙/V˙O2 relations which were notably steeper (slopes 114 to 187) than those observed during inhalation anaesthesia. More important, imposed increases in Q˙ and thus D˙O2 during anaesthesia (1.5 MAC) to rates comparable to that in the awake state produced a much less than proportional increase in V˙O2 without restoring it to baseline.Conclusions: Inhalation anaesthesia is characterized by a uniform Q˙/V˙O2 relation with an almost linear course at an anaesthetic concentration up to 2 MAC, regardless of the anaesthetic. Metabolic regulation of blood flow apparently operates also during inhalation anaesthesia up to 2 MAC so that the decrease in V˙O2 determines Q˙. This implies that cardiac output alone provides little information on the function of the circulation during inhalation anaesthesia unless related to metabolic demands, i.e. to V˙O2.
Luxury lung perfusion in end‐stage liver disease during liver transplantation
Authors: Stenqvist O. , Olausson M. , Karlsen K. L. 
Published: March 2003

Background: End‐stage liver disease is accompanied by a hyperkinetic circulation sometimes combined with hypoxaemia. Nitric oxide overproduction has been described as a possible cause by dilating the vasculature and decreasing cardiac afterload. The aim of this study was to evaluate haemodynamics, ventilation/perfusion matching, alveolar and alveolar dead space ventilation and resistance of systemic and pulmonary vasculature during liver transplantation.Methods: Ten liver transplantation patients were studied. Cardiac output, CO, was measured with thermodilution technique. Pulmonary shuntflow was calculated from standard formulas. Effective cardiac output, COeff, was defined as the CO in contact with alveolar ventilation, V˙A. Effective alveolar ventilation, V˙Aeff, was defined as V˙A in contact with pulmonary circulation. Measurements were performed during dissection, anhepatic and reperfusion phases.Results: During the dissection phase the shunt was 23±3%, COeff was 7.9±0.6 l/min, SVR was 620±67 dyn  ·  s/cm5, V˙Aeff was 3.4±0.5 l/min, SaO2 was 98±1% and Sv¯O2 was 86±2%. Corresponding values during the anhepatic phase were 16±2%, 5.6±0.4 l/min, 931±78 dyn  ·  s/cm5, 3.1±0.2 l/min, 99±1% and 88±1%. During the reperfusion phase the values returned to levels close to that of the dissection phase. The reduction of COeff between the dissection and the anhepatic phase was significant (P<0.01).Conclusions: The low vascular resistance is accompanied by a high cardiac output. In spite of the high shunt fraction, these patients were not hypoxaemic. This is explained by the fact that the increased cardiac output leads to a decrease in arterio‐mixed venous oxygen content difference and an increase in mixed venous oxygenation level, Sv¯O2 86–88%, normal value ≈70%. The V˙Aeff/COeff in this study was ≈0.5, i.e. the effective cardiac output, COeff is 235, 180 and 197% of the effective alveolar ventilation, V˙Aeff during the three phases. Thus, about twice the amount blood is oxygenated as compared to a normodynamic situation, which compensates for the effect of the shunt flow on oxygenation.
Effects of a leucocyte depleting arterial line filter on perioperative proteolytic enzyme and oxygen free radical release in patients undergoing aortocoronary bypass surgery
Authors: Mair P. , Hoermann C. , Mair J. , Margreiter J. , Puschendorf B. , Balogh D. 
Published: March 2003

Background: Proteolytic enzymes and oxygen free radicals released from activated leucocytes contribute significantly to the organ dysfunction associated with cardiopulmonary bypass. Leucocyte depletion during extracorporeal circulation should reduce the release of these toxic compounds and thereby improve postbypass myocardial and pulmonary function. Recently, a leucocyte‐specific arterial line filter to achieve leucocyte depletion during clinical perfusion has become commercially available. The aim of this study, therefore, was to evaluate the influence of the leucocyte depleting arterial line filter on proteolytic enzyme release, oxygen free radical release and postbypass pulmonary and myocardial function in patients undergoing bypass surgery.Methods: Forty patients undergoing elective aortocoronary bypass surgery were included into this prospective, randomized clinical study, 20 in the leucocyte depletion (LG‐6 group, leucocyte‐specific arterial line filter) and 20 in the control group (AV‐6 group, standard arterial line filter). White cell count, differential white cell count, plasma elastase concentration, plasma malondialdehyde concentration and C‐reactive protein were determined before, twice during and immediately after cardiopulmonary bypass, at the end of surgery and 6 and 20 h thereafter.Results: White cell count, differential white cell count, malondialdehyde and C‐reactive protein were not significantly different between LG‐6 and control patients. Plasma elastase concentrations were significantly (P≤0.03) higher during and immediately after extracorporeal circulation in LG‐6 group patients. Need for inotropic support, arterial pO2 after extracorporeal circulation and perioperative CK MB mass and troponin I release were not different between the two groups of patients.Conclusion: The use of a leucocyte depleting arterial line filter is associated with an increased release of the proteolytic enzyme elastase, but does not reliably and consistently achieve effective leucocyte depletion during clinical perfusion. In contrast to previous studies, we could not demonstrate any significant difference in postbypass pulmonary or myocardial function between patients perfused with the leucocyte‐specific arterial line filter and control patients. Our data do not support the routine use of a leucocyte depleting arterial line filter during clinical perfusion in patients undergoing elective aortocoronary bypass surgery.
Effects of ventilatory pattern on exhaled nitric oxide in mechanically ventilated rabbits
Authors: Forsberg S. , Ludwigs U. , Hedenstierna G. 
Published: March 2003

Background: Nitric oxide [NOexp] is present in exhaled air in many species. During experiments on pressure‐controlled inverse ratio ventilation (PCIRV) in rabbits, increased [NOexp] was observed during PCIRV. The present study was undertaken to clarify which component of PCIRV increased [NOexp].Methods: Three groups of six New Zealand White rabbits were anaesthetised and mechanically ventilated. Exhaled nitric oxide, lung mechanics and gas exchange were measured using an experimental protocol designed to assess the effects of variations in 1) flow profile, 2) inspiratory time and 3) time‐weighted tidal volume. Ventilator settings used were volume and pressure control ventilation at I:E ratios of 1:2 and 4:1.Results: Constant and decelerating flow gave comparable [NOexp] levels (20.0±6.4 vs. 21.9±7.7 ppb, n.s.) when time‐weighted tidal volume was kept constant. Using conventional (I:E 1:2) or inverted (I:E 4:1) I:E ratios in combination with decelerating flow and constant time‐weighted tidal volumes did not alter [NOexp] (26.0±3.6 vs. 24.0±5.8 ppb, n.s.). An increased time‐weighted tidal volume produced by pressure control with an I:E ratio of 4:1 increased [NOexp] (29.6±7.4) in comparison to constant (19.3±4.1, P<0.05) and decelerating flow ventilation (19.6±3.6, P<0.05) with I:E ratios of 1:2.Conclusion: The exhaled NO concentration was affected by ventilator setting. Increased levels of [NOexp] were observed with increases in time‐weighted tidal volume, whereas changes in flow pattern and inspiratory time did not seem to influence airway NO production or release.
Growth of Escherichia coli in propofol, lidocaine, and mixtures of propofol and lidocaine
Authors: Sakuragi T. , Yanagisawa K. , Shirai Y. , Dan K. 
Published: March 2003

Background: Microorganisms grow rapidly in propofol. Extrinsic contamination of propofol is thought to be a source of postoperative sepsis and wound infection. We studied growth of a strain of Escherichia coli in thiopental, propofol, lidocaine, and mixtures of propofol and lidocaine.Methods: The pathogen was exposed to 2.5% thiopental; 1.0% propofol; 1.0%, 2.0% and 4.0% preservative‐free lidocaine; and propofol solutions containing 0.25%, 0.5%, 1.0%, 2.0%, or 4.0% lidocaine for 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, and 24 h at room temperature, respectively. The inocula from these suspensions were cultured for 48 h at 37°C after the antimicrobial activity of the local anesthetics in the inocula was inactivated by a 1 : 1000 dilution with distilled water.Results: No organisms grew after exposure to 2.5% thiopental. The exposure of E. coli to propofol increased the colony count to approximately 90 times the control count. The colony counts of E. coli after exposure to 1.0%, 2.0% and 4.0% lidocaine and 0.25%, 0.5%, 1.0%, 2.0% and 4.0% lidocaine in 1.0% propofol were lower than the counts after exposure to 1.0% propofol (P=0.0048, 0.0027, 0.0003, 0.0503, 0.0188, 0.0080, 0.0044, and 0.0001, respectively). The growth rate of the microorganism was significantly higher in cultures exposed to 1.0% propofol than that in cultures exposed to lidocaine alone or lidocaine‐propofol mixtures (P<0.0001, respectively).Conclusion: Lidocaine possesses bacteriostatic activity against E. coli. Addition of lidocaine to propofol confers its bacteriostatic activity to the mixture and may decrease the hazard of infection associated with the extrinsic contamination of propofol.
Do blood levels of neuron‐specific enolase and S‐100 protein reflect cognitive dysfunction after coronary artery bypass?
Authors: Rasmussen L. S. , Christiansen M. , Hansen P. B. , Moller J. T. 
Published: March 2003

Background: Neuron‐specific enolase (NSE) and S‐100 protein have been used as markers for major brain damage. Cognitive dysfunction after cardiac surgery represents subtle brain damage that is detected by neuropsychological testing. We hypothesised that blood levels of NSE and S‐100 protein would increase after coronary artery bypass surgery and that the change in blood level would correlate with the change in cognitive function.Methods: We included 35 elderly patients undergoing coronary artery bypass surgery. Neuropsychological testing was performed before surgery and postoperatively at discharge from hospital and after 3 months using a neuropsychological test battery. Serum levels of NSE and S‐100 protein were measured before surgery and postoperatively after 24 h and 48 h.Results: Serum level of both NSE and S‐100 protein increased significantly 24 and 48 h after coronary artery bypass. Only the increase in NSE after 24 h was found to correlate with the degree of cognitive dysfunction at discharge from hospital. The increase in S‐100 protein after 24 h correlated significantly with the duration of cardiopulmonary bypass.Conclusion: NSE seems to be a useful blood marker for early cognitive dysfunction after coronary artery bypass surgery.
Preoperative anxiety is associated with a high incidence of problematic behavior on emergence after halothane anesthesia in boys
Authors: Aono J. , Mamiya K. , Manabe M. 
Published: March 2003

Background: In our clinical experience, children who are crying before anesthesia are more likely to show agitated behavior on emergence.Methods: One hundred and ten boys aged 3–6 years old (ASA 1) who underwent circumcision were studied. The children were assigned to one of two groups, depending on their attitude during induction: the anxious group and the calm group. Anesthesia was induced by inhalation of halothane in oxygen, and was maintained at 1% throughout surgery. For intra‐ and postoperative analgesia, caudal block with 0.5 ml/kg of 0.25% plain bupivacaine and topical infiltration with 1 to 2 ml of 1% lidocaine were provided for all patients. The incidence of delirium on emergence was compared between the groups.Results: We excluded 4 boys showing signs of incomplete pain relief. Twenty of 27 boys in the anxious group showed a significantly greater incidence of problematic behavior on emergence, compared to 5 of 79 in the calm group.Conclusion: The boys who were anxious before anesthesia showed a significantly greater incidence of problematic behavior on emergence from halothane anesthesia, compared with the boys who were calm before anesthesia.