bluuebunny/crossref_metadata_2025_split huggingface dataset:
Serum protein binding of propofol in patients with renal failure or hepatic cirrhosis
Authors: Costela J. L. , Jiḿenez R. , Calvo R. , Suarez E. , Carlos R. 
Published: January 2009

Background:Serum protein binding is a limiting factor in the access of drugs to the central nervous system. Disease‐induced modifications of the degree of binding may influence the effect of anesthetic drugs.Methods:The protein binding of propofol, an intravenous anaesthetic agent which is highly bound to serum albumin, has been investigated in serum samples from healthy volunteers, from patients with chronic renal failure not undergoing hemodialysis, from patients with chronic renal failure included in a regular hemodialysis program, and from patients with hepatic cirrhosis. Protein binding was determined by the ultrafiltration technique using an Amicon Micropartition System, MPS‐1.Results:The percentage of unbound propofol (mean(SD)) in healthy volunteers (n=16) was 0.98 (0.48) % showing a high interindividual variability. Chronic renal failure did not significantly modify serum protein binding of propofol. In the chronic renal failure group not undergoing regular hemodialysis (n=>9), unbound propofol was 0.92 (0.34) %. In addition, patients in periodic dialysis did not show changes in propofol binding either compared before (1.11 (0.33) %; n=13) or after hemodialysis (0.87 (0.38) %; n=12). A slight decrease in albumin concentration was found in all renal patients (P<0.05) in comparison to healthy volunteers. Creatinine and urea concentrations were higher in these patients (P<0.01) but in the postdialysis group, the differences in urea levels were not significant when compared with those of volunteers. No changes in the degree of propofol binding were observed in patients with hepatic cirrhosis (0.97 (0.30) %; n=14) when compared with the group of healthy volunteers. Significant differences were observed in albumin (P<0.01) and bilirubin (P<0.05) concentrations. Considering all subjects, the degree of binding did not correlate with biomedical data.Conclusion:Due to the the absence of significant changes in the protein binding it is unlikely that there will be an exaggerated pharmacological response in patients with renal and hepatic disease following the administration of a standard propofol dose, although due to interpatient variability careful titration can be recommended.
The efficacy of clonidine for reducing perioperative haemodynamic changes and volatile anaesthetic requirements in children
Authors: Nishina K. , Mikawa K. , Maekawa N. , Obara H. 
Published: January 2009

Background: Oral clonidine given as a premedicant in adults has been shown to reduce intraoperative inhalation anaesthetic requirements and provide perioperative haemodynamic stability. We conducted the current study to ascertain whether or not these beneficial effects of clonidine can be reproduced in children.Methods: In a prospective, randomized, double‐blind, controlled clinical trial, 60 children (ASA I) aged 5–11 yr, received placebo (control), 2 μg kg‐1 clonidine, or 4 μg kg‐1 clonidine orally 105 min before induction of anaesthesia. Anaesthesia was induced with halothane, nitrous oxide in oxygen via mask and maintained with halothane and 60% nitrous oxide in oxygen. The halothane concentration was titrated to the concentration required to maintain haemodynamic stability (defined as 20% of blood pressure (BP) and heart rate (HR)) for maintenance of anaesthesia. The end‐tidal concentration of halothane was monitored throughout anaesthesia. On completion of surgery, nitrous oxide and halothane were discontinued. Following confirmation of recovery from anaesthesia and muscle relaxation, the endotracheal tube was removed.Results: Higher inspired concentrations of halothane (%) were required in the control and 2 μg kg‐1 clonidine‐treated groups (mean SD: 1.1 ±0.2 and 1.0±0.2, respectively) than in the 4 μg kg‐1 clonidine‐treated group (0.6±0.1) for haemodynamic stability (P<0.05). Clonidine, 4 μg kg‐1, significantly reuced the intraoperative lability (coefficient of variation) of systolic and diastolic BP and HR compared with the other two regimens.Conclusion: Oral clonidine premedication at a dose of 4 μg kg‐1 provided intraoperative haemodynamic stability and reduced anaesthetic requirements in children. However, we are unable to extrapolate these observations to younger children and infants.
The interaction between nitrous oxide and isoflurane on suppression of learning: a study using classical conditioning in rabbits
Authors: El‐Zahaby H. M. , Ghoneim M. M. , Block R. I. 
Published: January 2009

Background:Nitrous oxide (N2O) is commonly combined with a volatile agent for administration of general anesthesia. We studied the effects of N2O and isoflurane on learning of the rabbit nictitating membrane responses (NMRs).Methods:Classical conditioning of the NMR was accomplished by presenting a 400 ms tone conditioned stimulus before the presentation of a 100 ms shock unconditioned stimulus over 6 daily training sessions. The percentages of conditioned responses (CRs) were calculated for animals treated with 0% (n=10), 33% (n=11), 67% (n=11), and 75% (n=7) N2O and for those treated with 0% (n=8), 0.2% (n=7), 0.4%, (n=13) and 0.8% (n=9) isoflurane separately. ED‐50 for suppression of learning for each drug were calculated. Percentages of CRs were calculated for treatments with combinations of 0.2% isoflurane with either 32 or 48% N2O (n=14, for each).Results:Isobolographic analysis demonstrated that the combination of the two drugs exerted no greater effect than that seen with either agent administered alone; for well‐established CRs (mean of days 5 and 6), the estimated concentrations corresponding to a rate of 70% CRs were 0.31% isoflurane with no N2O, 65.3% N2O with no isoflurane, and 0.2% isoflurane combined with 32.4% N2O.Conclusions:N2O and isoflurane interact additively on suppression of learning.
Comparison of the respiratory and systemic kinetics of nitrous oxide in the sheep
Authors: Reid M. A. , Mather L. E. , Isley A. H. , Runciman W. B. 
Published: January 2009

Background. To determine whether discrepancies in views on the kinetics of nitrous oxide (N2O) may have a methodological basis, we compared its kinetics, simultaneously, in the respiratory system and systemic circulation.Methods. Six merino ewes (40–50 Kg) were previously prepared with catheters in the pulmonary artery and aorta. The animals were anaesthetised with thiopentone then ventilated on a mixture of 70% N2O, 1% halothane in oxygen for 4 h. Simultaneous serial arterial and pulmonary arterial blood samples were assayed for N2O by gas chromatography and respiratory gases were monitored continuously by mass spectrometry.Results. Marked differences were observed between the respiratory and systemic kinetics of N2O uptake. While the expired/inspired N2O concentration ratio rose within 30 min to a value close to unity, the pulmonary arterial/arterial blood N2O concentration ratio did not reach unity during the 4 h of each study, but approached a constant rate of uptake shown by the mean ratio of 0.94 (SD 0.01) from about 2 h onward.Conclusions. Discrepancies in fluid flow between respiratory gas and the cardiovascular systems, a concentration effect of N2O in the lungs, the relative solubility of N2O in blood and tissues, and ventilation/perfusion inequalities all may contribute to the observed differences. The ongoing uptake is consistent with persistent extrapulmonary losses. There remains a need for experimental data on the pharmacokinetics of N2O. Unequivocal studies on the disposition of N2O can be undertaken only by using direct measurement of fluxes of N2O across relevant organs or tissues.
Dextran 70 and blood loss during transurethral resection of the prostate
Authors: Hahn R. G. 
Published: January 2009

Background: Dextran is an effective plasma expander but also a potential anticoagulant. This article attempts to establish the clinical significance of any increased intra‐operative blood loss associated with the use of dextran 70 during transurethral resection of the prostate (TURP).Methods: The blood loss was measured in used irrigating fluid by a photometer in 800 patients undergoing TURP. In 154 of them, 500‐1,000 ml of 6% dextran 70 was given for volume replacement. A regression model was used to test for interactions between the use of dextran and the operative parameters that correlated independently with the blood loss.Results: The bleeding varied between 10 and 3,825 ml (median 323). Operative parameters correlating to the blood loss were: weight of the prostatic resectate, operating time, irrigating fluid absorption, and systolic arterial blood pressure. The result of this regression analysis indicated that dextran did not increase the blood loss. Neither did the prostatic weight and operating‐time‐corrected blood loss increase when dextran was infused.Conclusion: There was no indication that dextran 70 given within the recommended dose range increases the blood loss during TURP.
Management of postoperative pain. An intervention study
Authors: Juhl I. U. , BÜlow H.‐H. , Nielsen P. R. , VidebÆk B. , Sonnenschein C. 
Published: January 2009

Background: In 1989 a study had shown that the quality of postoperative pain treatment (PPT) in a district general hospital was not satisfactory. Therefore, new instructions for PPT were issued, intra‐venous medication with morphine was introduced on the wards, and the staff was educated in PPT. The purpose of this study was to investigate the quality of PPT in 1992 compared to the quality in 1989.Methods: Using identical questionnaires, 191 patients in 1989 and 126 patients in 1992 were interviewed before and 2–5 days after surgery regarding postoperative pain. At the postoperative interview patients in pain also filled out the McGill Pain Questionnaire. A questionnaire was also answered by the nurses regarding PPT in 1989 and in 1992.Results: 1992 compared to 1989 (1992/1989): all patients were now medicated (100%/93%), most of them regularly (79%/4%) and the majority (94%/15%) also received non‐opioid analgesic. Fewer patients (65%/80%) experienced postoperative pain lasting more than one day following surgery. Analgesic prescription was more standardized.In 1992 the nurses were more satisfied than in 1989 with the PPT and the physicians' prescribing patterns.All the above‐mentioned parameters were significantly improved from 1989 to 1992.All the different pain‐scores showed a reduction (8–30%) but did not reach statistical significance (P=0.2).Conclusions: Our two investigations show that it is possible to improve the quality of pain management with rather simple reforms.
Anaesthesia and systemic oxygenation
Authors: Bacher A. , Mayer N. , Mittlboeck M. , Zadrobilek E. 
Published: January 2009

Background: Anaesthesia induction and deep anaesthesia may be accompanied by a considerable haemodynamic depression, especially in patients suffering from cardiovascular diseases. A decrease in cardiac index (CI) leads to a concomitant decrease in oxygen transport (DO2I). We examined whether these changes in haemodynamic performance and oxygenation can cause an oxygen debt and anaerobic metabolism.Methods: DO2I, oxygen uptake (VO2I), oxygen extraction ratio (O2ER) and plasma lactate were analysed at 9 pre‐defined study stages during anesthesia induction, deep anaesthesia prior to surgery and during surgery in 65 patients (ASA 3) undergoing elective vascular surgery. Polynomials of increasing order were fitted to the data for the determination of the critical value of oxygen transport from the inflection point of the regression curve.Results: CI, heart rate, mean arterial pressure and DO2I decreased significantly after anaesthesia induction and during deep anaesthesia. VO2I showed an almost parallel change during the study period so that O2ER remained nearly constant. Plasma lactate did not exceed the physiological range in any patient and a critical value of DO2I could not be detected because a linear regression always provided the best fit for the data.Conclusions: We conclude that in patients suffering from a substantial cardiovascular disease systemic oxygenation is not impaired by considerable haemodynamic changes induced by general anaesthesia. This fact can be explained by the parallel decrease in oxygen demand, expressed by the decrease in VO2I.
The combination of morphine with local anaesthetic in rhinoplasty ‐ no evidence of a peripheral morphine effect
Authors: Ben‐David B. , Moscona R. A. , Stahl S. 
Published: January 2009

Background:The recognition of a peripheral opioid action has prompted a number of clinical reports demonstrating a prolonged analgesic effect of peripheral opiate. As most studies have used a model of intraarticular instillation of narcotic we examined direct morphine infiltration of the surgical site in a unique clinical model.Methods:Sixty patients undergoing primary rhinoplasty were entered into this prospective, randomized, double‐blind study. Patients received a standard protocol of premedication, intravenous sedation, and nasal block. Two 2 ml syringes containing saline or morphine 3 mg in saline were provided for IM injection and for addition to the local anesthetic (IW, intrawound): Group I (control) ‐ saline IW, saline IM; Group II ‐morphine IW, saline IM; Group III ‐ saline IW, morphine IM. Intraoperative assessments included need for further sedation, need for further local anesthetic, and degree of bleeding. Recovery room analgesic requirements, pain scores, and recall of intraoperative pain were recorded prior to discharge. Followup phone calls at 24 hours recorded home pain scores and analgesic use during the first postoperative day.Results:Significantly more patients in Group II (9/20) required supplemental local anesthetic intraoperatively compared to Group I (2/20) and Group III (0/20). Significantly more patients in Group II (6/20) recalled their surgical experience as painful compared to Group I (1/20) and Group III (1/20). Group II patients also evidenced significantly more operative bleeding. There were no differences in postoperative pain scores, but Group I patients required analgesic in the recovery room significantly more than in Groups II and III (85%vs45% and 50%, respectively). There were no differences between groups in analgesic consumption at home.Conclusions:The results of this study indicate that the preoperative injection of intrawound morphine in combination with the local anesthetic both promotes bleeding and has an early pain‐enhancing effect while providing no late analgesic benefit beyond that of IM morphine.
Pharmacokinetics of piritramide after an intravenous bolus in surgical patients
Authors: Kietzmann D. , Briede I. , Bouillon T. , Gundert‐Remy U. , Kettler D. 
Published: January 2009

Background: Piritramide is a synthetic opioid analgesic which is commonly used for postoperative analgesia. It is structurally related to meperidine, exhibiting full μ‐receptor agonism. Pharmacokinetic data of the drug have not been reported so far.Methods: Plasma protein binding of piritramide was studied in vitro. The kinetics were examined after a single intravenous bolus (0.2 mg/kg) in 10 male patients aged 22–53 years undergoing elective minor surgery. Plasma and urine concentrations were determined by gas chromatography in samples drawn before and after the bolus. The concentration vs. time data were evaluated by nonlinear regression analysis, and the mean values and SD of the individual pharmacokinetic parameters were calculated. A three‐compartment body model was fitted to the data.Results: The volume of distribution at steady state was 4.7 (0.7) 1/kg, systemic plasma clearance was 7.8 (1.5) (mean (SD)) ml/kg/min. Renal clearance of unchanged piritramide was negligible (0.13 (0.09) ml/kg/min). The terminal elimination half‐life was 8.0 (1.4) h. In vitro, the free fraction in plasma of piritramide did not change over the therapeutic concentration range (5.5 (1.3)% at a pH of 7.35) but decreased considerably with pH within the physiological range.Conclusion: Since the elimination half‐life of piritramide appears to exceed the duration of clinically effective analgesia observed during the treatment of acute pain, the dose of piritramide should be titrated carefully during long‐term treatment to avoid accumulation that may lead to adverse effects.
Age and life‐sustaining treatment Attitudes of intensive care unit professionals
Authors: Melltorp G. , Nilstun T. 
Published: January 2009

Background: In Sweden, the official policy is that life‐sustaining treatment should not be denied because of chronological age. This policy is also emphasised in a recent official report on priority setting in health care. But is this policy accepted among health care professionals? Do they consider chronological age relevant when decisions to forgo life‐sustaining treatment are to be made?Method: Questionnaire survey to physicians, registered nurses and enrolled nurses at the Intensive Care Unit, University Hospital MAS, Malmö, Sweden.Results: More than 65% of the respondents were of the opinion that chronological age per se influenced decisions about life‐sustaining treatment. Fewer, a little more than 40%, answered that it would make a difference to their own judgment about life‐sustaining treatment whether the patient is 25 or 75 years old. The respondents were also confronted with 10 different factors characterising patients in need of life‐sustaining treatment. According to a majority, advance directive, decision‐making capacity, and chronological age should be taken into consideration in these situations.Conclusion: The results indicate that chronological age is used as a criterion when decisions to forgo life‐sustaining treatment are to be made in the ICU. Many health care professionals also believe that chronological age should be used as a criterion. This is clearly discordant with the official policy in Sweden and other countries, which is that age‐based rationing is never justified.
Hemodynamic effects of tracheal and intravenous adrenaline in infants with congenital heart anomalies
Authors: Jonmarker C. , Olsson A.‐K. , Jögi P. , Forsell C. 
Published: January 2009

Background: If intravenous access cannot be accomplished during cardiopulmonary resuscitation in children, tracheal administration of 100 μg/kg of adrenaline (ten times greater than the intravenous dose) is recommended.Methods: In a randomized crossover study we recorded the hemodynamic effect of a low dose of intravenous adrenaline and a ten times greater tracheal dose. While anesthetized for open heart surgery, fourteen infants received one dose of adrenaline intravenously (0.3 μg/kg) and the other tracheally (3μg/kg).Results: During the first 5 minutes after administration mean arterial pressure (MAP) and heart rate (HR) increased after both intravenous and tracheal administration (P<0.001). The maximum increase in MAP was 28% (17–68%, median and range) after intravenous injection and 20% (6–69%, P<0.05 when compared to intravenous injection) after tracheal instillation. In four infants, MAP increased less than 10% after tracheal instillation. The maximum increases in MAP and HR occurred 1 min (1–2 min) after intravenous injection and 3 min (2–4 min) after tracheal instillation (P<0.001).Conclusion: Tracheal administration of 3 μg/kg adrenaline increased mean arterial blood pressure in infants with congenital cardiac anomalies, but the increase occurred later and was less consistent than after 0.3 μg/kg of adrenaline given intravenously.
A paediatric canopy system for aerosol administration and minimized environmental pollution
Authors: WÅhlin B. , Malmström B. , Soop M. , Hellströ;m L.‐G. 
Published: January 2009

Background: A canopy system for ribavirin aerosol administration to infants has been developed in order to improve the control of aerosol treatment, facilitate access to the infant and minimize environmental pollution. The system comprises a transparent canopy, fitted with four sealable apertures. An evacuation flow that is 3 1/min higher than the gas supply was anticipated to prevent aerosol leakage from the canopy.Method: In a clinical evaluation, 10 infants with body weights of 1.8‐7.1 kg were placed inside the canopy during 1 hour of simulated treatment. The temperature, relative humidity and carbon dioxide concentration within the canopy were measured repeatedly to study the stability of these variables and their dependence on body weight. Infant body temperature, skin temperature and the respiratory frequency were measured. In a laboratory evaluation, aerosol leakage was studied using an ambient air admixture procedure and smoke tests. The sound level inside the canopy was measured.Results: All physical variables inside the canopy remained stable. The sound level was 52 dBA. The carbon dioxide concentration (1000–3900 PPM) correlated with infant body weight (P<0.001), as did canopy temperature (25.1–29.6°C, P<0.05). The relative humidity was 52–88%. Infant body temperatures were not influenced. The respiratory frequency decreased by 13% (P<0.01). No aerosol leakage was observed. Conclusion: The canopy system facilitates a controlled aerosol therapy with good infant surveillance and accessibility, a minimum of environmental pollution and a comfortable physical environment without apparent risks of carbon dioxide rebreathing or cooling stress at body weights of 1.8‐7.1 kg.
High energy phosphates and direct calorimetry as predictive parameters for metabolic recovery of the rat liver following ischemia
Authors: Bach F. , Singer D. , Schmiedl A. , Bauer M. , Larsen R. 
Published: January 2009

Backround and Methods: Alteration of the hepatocellular function following ischemic damage may play a crucial role in the limited recovery after reperfusion. In spite of numerous efforts, finding a simple technique for predicting recovery of the liver after ischemic damage is still an unresolved problem. During ischemic storage of isolated rat livers at 25°C tissue concentrations of high energy phosphates and lactate were determined photometrically and interstitial pH was measured by glass electrodes. In comparison, the metabolic rate was measured continuously by direct calorimetry. In a second series of experiments these results were compared with functional recovery after ischemia and reperfusion. Following ischemic storage at 25°C for 60, 120 or 240 min, the isolated livers were reperfused for 30 min in a non‐recirculating system with a constant flow rate. During reperfusion functional recovery, as assessed by oxygen consumption and bile flow, was determined. At the end of reperfusion tissue samples were taken for biochemical analysis of adenine nucleotides. Furthermore, morphologic integrity was determined by electron microscopy.Results: Whereas the ATP concentration drops within 60 min of ischemia to 6.9% of the control value without further significant change, the continuously measured metabolic rate as assessed by direct calorimetry decreases in an exponential manner. Accordingly, a better correlation of hepatocellular secretory function and calorimetrically measured heat output (r2=0.85; P<0.001) was observed than with high energy phosphates (r2=0.56; P<0.001).Conclusions: These data suggest that if the metabolism of the ischemic rat liver falls below a critical level, recovery is incomplete or impossible. Therefore, assessment of the global metabolic rate by direct calorimetry seems not only to be a very good predictor of recovery after ischemic damage but also a good tool in the laboratory for studies concerning the sequelae of ischemic metabolism and for improvement of tissue protection.