bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ropivacaine in peribulbar block: a comparative study with bupivacaine
Authors: Nociti J. R. , Mateus Serzedo P. S. , Zuccolotto E. B. , Cagnolati C. A. , Machado Nunes A. M. 
Published: March 2003

Background: Ropivacaine is a new local anesthetic with alleged lower systemic toxicity and slightly lower potency as compared with bupivacaine. The present study aimed to evaluate the efficacy of ropivacaine in peribulbar block, as compared with that of bupivacaine.Methods: Eighty patients aged 45–92 years with physical status ASA I, II, or III were randomized to Group R (n=40) or Group B (n=40). Group R received 8.0 ml of 1.0% ropivacaine and Group B received 8.0 ml of 0.75% bupivacaine, both solutions with 50 IU/ml hyaluronidase, to induce peribulbar block according to the double‐injection technique. Decreased ocular motility was the only criterion of successful block.Results: The percentage of patients with decreased ocular motility showing successful block was higher in Group R 1 and 5 min after injection. A score indicating successful peribulbar block was found in all patients 10 min after injection. While no patient complained of a burning sensation during ropivacaine injection, 22.5% of the patients given bupivacaine reported this symptom.Conclusion: Both local anesthetics were effective in inducing peribulbar block for intraocular surgery. A tendency was noted to a faster onset of peribulbar block with ropivacaine; nevertheless, both drugs had a high degree of success for this block.
Patients with poor preoperative ejection fraction have a higher plasma response of adrenomedullin in response to open heart surgery
Authors: Amado J. A. , Fidalgo I. , García‐Unzueta M. T. , Montalbán C. , Del Moral I. , Pazos F. , Diago C. 
Published: March 2003

Background: Adrenomedullin (AM) is a potent vasodilator peptide. Plasma AM levels are increased in heart diseases and in sepsis. Heart surgery under cardiopulmonary bypass (CPB) induces a systemic inflammatory response.Methods: We measured plasma AM, cAMP (the second messenger of AM), C‐reactive protein (CRP) and haemodynamic parameters in 29 patients undergoing elective open heart surgery, before, during and after anaesthesia and CPB as well as on the first morning after surgery.Results: Basal AM levels were higher than normal and correlated with systolic pulmonary pressure and pulmonary capillary pressure, but not with other haemodynamic parameters. AM increased during CPB and remained elevated 24 h after the start of surgery. Plasma cAMP increased only at the end of CPB. CRP was increased only in the last sample. At the end of CPB and at the end of surgery AM levels were higher in patients with basal ejection fraction<40% compared with those with ejection fraction >60% [456±386 vs 252±343 (P<0.03) and 832±781 vs 391±356 pg/ml (P<0.05), respectively].Conclusion: We conclude that AM, as inflammation‐related cytokines, increases during and after CPB, that cAMP response is unrelated to AM and that AM response is higher in those patients with worse basal ejection fraction.
Factors predicting atracurium reversal time
Authors: Kirkegaard‐Nielsen H. , Severinsen I. K. , Pedersen H. S. , Lindholm P. 
Published: March 2003

Background: To identify individual factors and combination of factors predictive of reversal time (defined as time from neostigmine administration to train‐of‐four (TOF) ratio 0.70) from atracurium‐induced neuromuscular block, the present study tested the following variables as possible predictors of reversal time: 1) degree of block at the time of antagonism as quantified by first response to TOF or double‐burst stimulation (DBS); 2) time from last supplemental dose of atracurium to administration of neostigmine (pre‐reversal time); and 3) time from administration of initial atracurium dose to T1 (the magnitude of the first twitch in TOF) recovered to 10% (duration of action of the initial dose of atracurium).Methods: The study population comprised 83 female patients, ASA physical status 1 or 2, anaesthetized with fentanyl, thiopental, halothane and nitrous oxide. Initial and supplemental doses of atracurium were 0.5 mg · kg−1 and 0.15 mg · kg−1, respectively. Evoked responses to TOF or DBS were recorded mechanomyographically. Neuromuscular block was antagonized with neostigmine, 0.07 mg · kg−1, at varying time intervals (6–50 min) after the final atracurium dose.Results: Multiple linear regression analyses testing T1, D1 (the magnitude of the first twitch in DBS), pre‐reversal time and duration of action of the initial dose of atracurium, demonstrated that with superficial block, T1 >15%, T1 is the only significant predictor for reversal time. With moderate block, 0< T1 ≤15%, both T1 and duration of action of the initial atracurium dose are significant predictors for reversal time. With profound block, T1=0, duration of action of the initial dose and pre‐reversal time are significant predictors for reversal time.Conclusion: 1) T1 is a more important predictor for reversal time from atracurium‐induced neuromuscular block than D1; 2) predictors differ with the degree of block: with T1 >15%, T1 is the only significant predictor; with 0< T1 ≤15%, the duration of action of the initial dose and T1 are predictors for reversal time; with T1=0 , the duration of action of the initial dose and pre‐reversal time predict reversal time.
Is total body weight an appropriate predictor for propofol maintenance dose?
Authors: Hirota K. , Ebina T. , Sato T. , Ishihara H. , Matsuki A. 
Published: March 2003

Background: Infusion rate of propofol during anaesthesia is usually based on total body weight. In this study, we have determined the relationship between total body weight and plasma propofol levels when the infusion rate was based on total body weight.Methods: Sixty patients undergoing elective surgery were studied. Anaesthesia was induced with propofol 1 mg  ·  kg−1, ketamine 1 mg  ·  kg−1 and fentanyl 2 μg  ·  kg−1, and maintained with propofol 5 mg  ·  kg−1  ·  h−1, ketamine 0.5–1 mg  ·  kg−1  ·  h−1 and fentanyl 5–15 μg  ·  kg−1. Propofol infusion rate did not change during anaesthesia, and infusion was terminated at the end of surgery. Immediately prior to termination of the propofol infusion, arterial blood (5 ml) was collected to measure plasma level of propofol by a high‐performance liquid chromatography equipped with electrochemical detection.Results: There was a significant correlation between plasma propofol and total body weight (r=0.646, P<0.001). Plasma propofol concentration also correlated with infusion rate, corrected to lean body mass (r=0.527, P<0.001).Conclusion: During a fixed infusion rate, plasma propofol concentration may be dependent on total body weight.
Warming of insufflation gas during laparoscopic hysterectomy: effect on body temperature and the autonomic nervous system
Authors: Nelskylä K. , Yli‐Hankala A. , Sjöberg J. , Korhonen I. , Korttila K. 
Published: March 2003

Background: Hypothermia is a known side effect of laparoscopic operations. It may increase the sympathetic activity of the autonomic nervous system (ANS), which can be evaluated non‐invasively by heart rate variability (HRV). We tested the hypothesis that warming of the delivered CO2 insufflation gas helps to maintain the normal body temperature.Methods: Thirty‐seven healthy women undergoing laparoscopic hysterectomy were randomized into heated (37°C, n=18) or unheated (24°C, n=19) gas insufflation groups. Anesthesia was induced with propofol and maintained with sevoflurane in O2‐air. Tympanic (ttymp) temperature was recorded before, during and after the operation. Nasopharyngeal (tnaso) temperature was recorded only during operation. Electrocardiograms were recorded and stored to evaluate changes in HRV. The individual changes in HRV were compared after decibel (dB) transformation.Results: A median decrease in tympanic temperatures during the operation was 0.7°C in the heated and 0.3°C in the unheated group (P=0.01 between groups), and in nasopharyngeal 0.3°C and 0.1°C (P=0.03), respectively. Preanesthetic tympanic values were reached within 90 min after anesthesia. After dB transformation, HRV high frequency power differed between the groups. It was better preserved in the patients receiving unheated gas.Conclusion: The heating of insufflation gas does not prevent a decrease in body temperature and is thus unnecessary during laparoscopic hysterectomy.
Changes in stroke volume cause change in cardiac output in neonates and infants when mean airway pressure is altered
Authors: Gullberg N. , Winberg P. , Selldén H. 
Published: March 2003

Background: Based on early studies in the lamb, and in spite of more recent studies in humans, it has been the received opinion that neonates and infants can not change their stroke volume significantly, but are mainly dependent on changes in heart rate, to change cardiac output. To further evaluate the relationship between cardiac output and stroke volume during mechanical ventilation of neonates and infants, we have studied the effects on cardiac output and stroke volume by two different ways of changing mean airway pressure.Methods: In one group, mean airway pressure was decreased by using a patient triggered mode: pressure support ventilation; in the other, mean airway pressure was increased by increasing positive end‐expiratory pressure (PEEP). Changes in cardiac output, heart rate and stroke volume were assessed with the Doppler technique, measuring blood flow velocity in the ascending aorta.Results: Without a significant change in heart rate, we found a significant increase in cardiac output of +16±2% (P<0.01) with a decrease in mean airway pressure and a decrease in cardiac output of −13±4%, (P<0.02) with an increase in mean airway pressure, depicting a change in stroke volume of +17±2% (P<0.02) and −14±5%, (P<0.01) respectively.Conclusions: We conclude that neonates and infants are able to regulate cardiac output by changing the stroke volume to a greater extent than presumed, at least when cardiac output is influenced by changes in the mean airway pressure.
Mild hypothermia does not increase blood loss during total hip arthroplasty
Authors: Johansson T. , Lisander B. , Ivarsson I. 
Published: March 2003

Background: The effects of mild hypothermia on blood loss are little known.Methods: Patients, undergoing primary prosthetic hip surgery under spinal anaesthesia, were randomised to the operative procedure, with (n=25) or without (n=25) forced air warming. Core temperature was repeatedly measured from the tympanic membrane. The blood loss was calculated by three different methods; the intraoperative loss was estimated visually. The loss during and after the operation was obtained by determination of lost haemoglobin (the Hb‐method). The blood loss during hospital stay was also calculated from the haemoglobin balance.Results: Among controls, core temperature decreased by 1.3±0.6°C (mean±SD) and in the warmed patients 0.5±0.4°C (P<0.0001). Preoperative variables and the number of allogeneic units transfused did not differ between the groups. In controls, the blood loss during operation was, with the visual method, 698±314 ml, compared with 665±292 ml in warmed patients. With the Hb‐method, the loss was 662±319 and 657±348 ml, respectively. With this method, the external loss during the entire hospital stay was, in controls, 1066±441 ml and in the warmed group, 1047±413 ml. The balance method yielded 1674±646 ml and 1507±652 ml, respectively. Indices of blood loss did not differ significantly between groups and there was no covariation between those variables and the decrease in core temperature.Conclusions: Forced air warming did not decrease the blood loss. Methods for determination of blood loss yielded widely differing results.
Ketamine does not inhibit inflammatory responses of cultured human endothelial cells but reduces chemotactic activation of neutrophils
Authors: Zahler S. , Heindl B. , Becker B. F. 
Published: March 2003

Background: Ketamine is a widely used general anaesthetic, which has been reported to inhibit neutrophil function and neutrophil‐endothelial interaction. To date, however, it is unknown whether ketamine has any direct effects on endothelial cells with respect to inflammation. Therefore, we investigated the influence of varying concentrations of ketamine (0.5, 1, and 3 μM) on the endothelial expression of cytokines and adhesion molecules with relevance for inflammation.Methods: Cultured human umbilical vein endothelial cells were stimulated with tumor necrosis factor alpha (TNFα, 2.5 ng/ml) for 4 h in the absence or presence of ketamine. The adhesion molecules ICAM‐1 and E‐selectin on the endothelial cells were measured by flow cytometry. Release of the proinflammatory cytokines IL‐6 and IL‐8 by endothelial cells was quantified by ELISA. The acute effect of ketamine on leukocyte activation by the supernatant of endothelial cells pre‐stimulated with TNFα (4 h) was tested by flow cytometric measurement of CD11b, a leukocyte activation marker, after 15 min of coincubation.Results: TNFα caused dramatic upregulation of both adhesion molecules (15‐fold and 5‐fold vs. control for ELAM‐1 and ICAM‐1, respectively) and of both cytokines (500‐fold and 1.8‐fold for IL‐6 and IL‐8, respectively). No concentration of ketamine employed in our study had any effect on these inflammatory parameters. However, activation of leukocytes by supernatant of TNFα‐conditioned endothelial cells (70% increase of CD11b) was attenuated by coincubation of the PMN with 0.5 and 5 μM ketamine (47% and 44% increase, respectively).Conclusion: These data suggest that ketamine exerts its anti‐inflammatory actions primarily via inhibition of leukocyte reactivity. Indeed, no inhibition of endothelial responses was detectable in our study.
Passive expiratory flow‐volume curve is not an accurate method to measure the respiratory time constant in rabbits
Authors: Vialet R. , Monnier A. , Lagier P. , Jammes Y. , Toméi C. , Martin C. 
Published: March 2003

Background:: In mechanically ventilated patients, inspiration is forced by an externally applied positive pressure whereas expiration remains passive and depends on the time constant of the total respiratory system (τ), which constitutes an important determinant of mechanical ventilation. The end‐inspiratory occlusion technique is one of the easiest methods to obtain τ values in ventilated patients, especially infants, but its accuracy is not well established. The aim of this study was to compare in anesthetized, paralyzed rabbits τ values given by the end‐inspiratory occlusion technique (τrs) to τ values obtained by references methods for measurements (i.e. the product of static lung compliance by airway resistance: τref) during carbachol‐induced bronchospasm eliciting marked modifications of the respiratory mechanics.Methods: Comparisons were made in the basal state and after carbachol‐induced bronchoconstriction in seven New Zealand adult rabbits. This procedure resulted in a wide range of expiratory time constants. A pneumotachograph was used to measure expiratory flow and volume before and after end‐inspiratory occlusion. The slope of the flow volume curve gave τrs. Then τrs was compared with τref (which ranged from 0.30 to 1.96 s).Results: Statistical analysis revealed a weak correlation between the two methods, and a size‐dependent bias of τrs measurements.Conclusions:: The end‐inspiratory occlusion technique leads to a systemic bias in measurements of respiratory time constant, especially when the resistance of the respiratory system is elevated.
Intraarticular, epidural, and intravenous analgesia after total knee arthroplasty
Authors: Klasen J. A. , Opitz S. A. , Melzer C. , Thiel A. , Hempelmann G. 
Published: March 2003

Background: After total knee arthroplasty, patients regularly suffer from severe pain. It is unclear whether epidural or systemic pain therapy is superior in terms of postoperative pain relief, patients’ comfort and side effects. A new therapeutic approach, intraarticular opioids, has been suggested with the detection of opioid receptors in inflamed tissue. This method has proven suitable for clinical use in small operations (e.g. knee arthroscopy). In this study, we compared epidural analgesia and intraarticular application of morphine plus “on‐demand” intravenous analgesia to “on‐demand” intravenous analgesia alone.Methods: Thirty‐seven patients, scheduled for total knee arthroplasty, were randomly assigned to three treatment groups: in group 1 (EPI) patients received bolus doses of morphine via an epidural catheter; in group 2 (IA) an intraarticular bolus of 1 mg of morphine was applied at the end of the operation with subsequent use of a patient‐controlled analgesia (PCA) pump; group 3 (Control), in which only PCA was provided, served as control for both analgesic procedures. Main outcome measures included visual analogue pain scales, total morphine consumption, and stress hormones.Results: No statistically significant differences in visual analogue pain scales could be detected between the three groups. Application of intraarticular morphine did not reduce the amount of analgesics required for postoperative analgesia as compared to intravenous analgesia alone. Application of epidural morphine significantly suppressed β‐endorphine release, but did not significantly influence other stress hormones as compared to the control group.Conclusion: Epidural and intravenous analgesia after total knee arthroplasty are equivalent methods of pain relief. In major orthopaedic procedures, application of intraarticular morphine does not reduce analgesic requirements.
Lateral infraclavicular plexus block vs. axillary block for hand and forearm surgery
Authors: Kapral S. , Jandrasits O. , Schabernig C. , Likar R. , Reddy B. , Mayer N. , Weinstabl C. 
Published: March 2003

Background: In the last few years infraclavicular plexus block has become a method of increasing interest. However, this block has been associated with high complication incidences and without advantage in the quality of blockade over the axillary approach. We prospectively studied 40 patients (ASA I–III) undergoing surgery of the forearm and hand, and investigated the performance of the lateral infraclavicular plexus block against an axillary paravascular block to evaluate the success rate as well as the extent and quality of blockade.Methods: Patients were randomized into two groups: group I (lateral infraclavicular approach; n=20) and group A (axillary approach; n=20). The lateral infraclavicular approach is a technique with the coracoid process (CP) as landmark. Alone the sagittal plane, the needle is inserted until contact with the CP. The needle is then withdrawn 2–3 mm and reinserted directly under the CP, until it contacts the brachial plexus sheath. Plexus blockade was performed using 40 ml of mepivacaine 1%. Quality of sensory and motor block was recorded selectively for each nerve distribution at close intervals for 6 h.Results: Successful block according to Vester‐Andersen’s criteria was achieved in 100% of group I and 85% of group A. In group I, a pronounced sensory and motor blockade of the musculocutaneous nerve was observed, while patients of group A had a weak block of this nerve. In group I, an additional spectrum of nerves (thoracodorsal, axillary and medial brachial cutaneous nerves) was involved compared to group A. There was no difference among groups in onset and duration of block.Conclusion: Based on the safe landmark and feasibility of this procedure and the additional spectrum of nerve block achieved, the application of lateral infraclavicular technique has to be reconsidered in clinical practice.
Effects of propofol on isolated human pial arteries
Authors: Wallerstedt S. M. , Reinstrup P. , Uski T. , Bodelsson M. 
Published: March 2003

Background: The intravenous anaesthetic propofol has been reported to increase cerebral vascular resistance in vivo. The underlying mechanisms are not fully understood, but may include effects on metabolism and direct effects on the vascular smooth muscle. The present study was designed to evaluate the direct effects of propofol on human pial arteries.Methods: We investigated the direct effect of propofol (10−6–10−4 M) on isolated human pial arteries at basal tension as well as the influence on contractions induced by 5‐hydroxytryp?ta?mine, prostaglandin F2α, noradrenaline and potassium chloride.Results: Propofol did not change the basal tension. Propofol at 10−6 and 10−5 M did not affect the concentration‐response curves of any of the contractile agents tested. Propofol at the supraclinical concentration 10−4 M reduced the contractions induced by all contractile agents.Conclusion: Propofol reduces the tone of human pial arteries in vitro at supraclinical concentrations, but has no effect on the tone at clinically relevant concentrations.
Effects of desflurane on the pig intestinal circulation during hypotension
Authors: Sundeman H. , Åneman A. , Broomé M. , Haney M. , Johansson G. , Häggmark S. , Biber B. , Winsö O. 
Published: March 2003

Background: The aim of the present study was to analyze the perfusion pressure dependency for the splanchnic vascular effects of desflurane (DES).Methods: We measured portal blood flow (QPORT, perivascular ultrasound) and jejunal mucosal perfusion (JMP; laser Doppler) in pentobarbital‐anesthetized pigs (n=10). Experimentally, decreases in mean arterial pressure (MAP) were produced by pericardial infusions of dextran. The protocol included sets of measurements at incremental doses of DES (1, 2, 4 and 6%) prior to and during pericardial infusions.Results: Although QPORT and JMP decreased significantly during pericardial infusions, DES, irrespective of dose, did not reduce QPORT until MAP had decreased below 65–70 mm Hg. In higher MAP ranges, vasodilation in pre‐portal tissues was powerful enough to maintain QPORT in spite of concurrent decreases in driving arterial pressure, as produced by either DES or pericardial infusion, or by a combination of both. We found no effects of DES on JMP even at very low MAP (about 40 mm Hg during pericardial infusion), indicating that the normal physiological response of the small intestine to redistribute blood flow from deeper to more superficial layers during hypotension was unimpaired by DES.Conclusions: Our data suggest a wide dose‐tolerability of DES as regards the splanchnic circulation during hypotensive states.
Movement of the endotracheal tube during laparoscopic hernia repair
Authors: Mendonca C. , Baguley I. , Kuipers A. J. , King D. , Lam F. Y. 
Published: March 2003

Background: Laparoscopic surgery is not without its problems, and one of the less known is cephalad displacement of the carina and relative movement of the endotracheal tube in the trachea. The aetiology of this is presumably a consequence of both pneumoperitoneum and the Trendelenburg position frequently adopted during laparoscopic surgery.Method:We studied 30 patients undergoing laparoscopic hernia repair utilising 10° of Trendelenburg position and an intra‐abdominal inflation pressure of between 12 and 15 mm Hg (mean 13.6 mm Hg). We measured the distance between the tip of the endotracheal tube and the carina using a fibreoptic bronchoscope.Result:This distance decreased only slightly, from a mean (SD) of 39.6 (13) mm after intubation, to 38.9 (12.6) mm after adoption of Trendelenburg tilt and pneumoperitoneum. This did not represent a statistically significant change (P=0.09).Conclusion: We conclude that the endotracheal tube does not routinely migrate towards the carina when laparoscopic hernia repair is performed under these conditions.