bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of pressure/volume loops based on intratracheal pressure measurements during dynamic conditions
Authors: Kárason S. , Søndergaard S. , Lundin S. , Wiklund J. , Stenqvist O. 
Published: March 2003

Background: The aim of this study was to evaluate and compare information about lung mechanics obtained by dynamic pressure/volume loops based on Y‐piece and intratracheal airway pressure.Methods: Airway pressure was measured simultaneously at the Y‐piece and trachea. Flow/tidal volume was measured by side‐stream spirometry at the Y‐piece. The effect of an intraluminal catheter in the tube was evaluated in a lung model. Ten adults with acute lung injury and mechanical ventilation were studied. Measurements were performed during volume‐(VC) and pressure‐controlled (PC) ventilation at different ventilator settings.Results: Lung model: There was a statistically significant difference (P<0.001) between trachea and Y‐piece pressure/volume loop areas during both VC and PC ventilation. The ratio trachea area/Y‐piece area decreased with increased endotracheal tube resistance (r=0.96). Patients: The difference between trachea and Y‐piece P/V‐loops was statistically significant at all 21 ventilatory settings (P<0.05–0.001). The tracheal loop revealed clearly intrinsic PEEP and lowered compliance during overinflation, which was difficult or impossible to see in the Y‐piece pressure/volume loop.Conclusion: By measuring airway pressure at the trachea the effect of endotracheal tube resistance during inspiration is excluded while it is included during expiration, yielding correct end‐points of inspiration and expiration. This makes it possible to calculate accurately total compliance of the respiratory system during dynamic conditions. By monitoring of airway pressure in the trachea, respiratory mechanics can be assessed more accurately and ventilatory settings adjusted to attenuate ventilator induced lung injury.
Cardiac troponin I is reliable with immediate but not medium‐term cardiac complications after abdominal aortic repair
Authors: Godet G. , Dumerat M. , Baillard C. , Ben Ayed S. , Bernard M.‐A. , Bertrand M. , Kieffer E. , Coriat P. 
Published: March 2003

Background: The diagnosis of cardiac complications is particularly challenging in the postoperative course of non‐cardiac surgery. Follow‐up of patients suggests that silent or symptomatic postoperative myocardial infarction have similar short‐term outcomes. Cardiac troponin I (cTnI) has been reported as being a sensitive and specific marker of these complications.Methods: We conducted a prospective study to determine the cut‐off values of cTnI which may predict cardiac complications, i: in the postoperative period until discharge, and ii: during a 1‐year period after aortic surgery. Three hundred and twenty‐nine consecutive patients undergoing infrarenal aortic surgery were included over a 2‐year period in a single center. cTnI was measured at recovery and on the 1st, 2nd and 3rd postoperative days. The presence or absence of cardiac complications was classified by reviewers who had no knowledge of cTnI. For evaluation of the ideal discrimination value of cTnI between the complicated and uncomplicated patient groups, we calculated receiver‐operator characteristics for the mean values of the peak of cTnI.Results: Thirteen patients (4%) developed 19 postoperative cardiac complications. Thirteen patients (4%) died in the postoperative period. Nine patients (3%) developed 10 cardiac complications during the 1‐year follow‐up in 316 patients. In 280 patients, cTnI was below 0.5 ng/ml, in 22 patients between 0.5 and 1.5 ng/ml and the 27 remaining patients had a cTnI higher than 1.5 ng/ml. The area under the curve for postoperative cardiac complications was 0.84 (SD=0.21). A limit value of 0.54 ng/ml yielded a sensitivity of 75% and a specificity of 89%. The area under the curve for late cardiac complications was 0.45 (SD=0.13).Conclusion: A cTnI level greater than 0.54 ng/ml appears to be correlated with the occurrence of cardiac complications in the period until discharge, but no value of cTnI is predictive of late cardiac complications occurring in the 1st year after aortic surgery.
Lipid peroxidation induced by an early inflammatory response in endotoxaemia
Authors: Basu S. , Eriksson M. 
Published: March 2003

Background: Endotoxaemic challenge promptly causes lipid peroxidation. Porcine endotoxaemia can be used to replicate severe human septic shock. This model was used to evaluate non‐enzymatic [8‐Iso‐prostaglandin F2α (8‐Iso‐PGF2α)] and enzymatic [15‐keto‐13,14‐dihydro‐prostaglandin F2α (15‐K‐DH‐PGF2α)] lipid peroxidation, respectively, in relation to survival. The aim of this study was to correlate, if possible, pathophysiologic events during endotoxaemia to the levels of these arachidonic acid metabolites.Methods: Nineteen pigs were anaesthetised, monitored (circulatory and respiratory variables in relation to lipid peroxidation) and given a continuous 6 h E. coli endotoxin (10 μg · kg−1 · h−1) infusion. All animals were mechanically ventilated at constant tidal volumes and the inspired oxygen fraction was kept constant during the experimental period.Results: This endotoxin infusion caused expressed derangements in all pigs and death in 9 of them. The levels of 8‐Iso‐PGF2α, indicating oxidative injury, were different in time course, magnitude and fashion between survivors and non‐survivors. The levels of 15‐K‐DH‐PGF2α, indicating inflammatory response, showed a similar pattern. At 1 h the CO2 partial pressure in arterial blood was significantly higher in non‐surviving pigs and correlated (r: 0.7; P<0.05) to the levels of 15‐K‐DH‐PGF2α. Prostaglandin F2α is mainly metabolised in the lung. The lung weights were significantly (P<0.05) higher in non‐surviving than in surviving animals. Both free radical and cyclooxygenase catalysed oxidative modification occurs during endotoxaemia.Conclusion: Increased metabolism and inflammation, as evaluated by 15‐K‐DH‐PGF2α, in the group of non‐survivors may mediate the increase in arterial CO2. Thus, increased lipid peroxidation seems to be associated with endotoxaemic organ dysfunction and increased mortality.
Effects of melagatran, an inhibitor of thrombin, on fibrin deposits, haemodynamics, and platelet count in endotoxaemic pigs
Authors: Eriksson M. , Saldeen T. , Mattsson C. , Larsson A. 
Published: March 2003

Background: Thrombin plays a pivotal role in the development of septic shock. Porcine endotoxaemia can replicate this condition. We wanted to evaluate whether melagatran, a novel inhibitor of thrombin, would counteract some of the endotoxin‐induced changes in this model.Methods: Fifteen pigs were anaesthetised, monitored (circulatory and respiratory variables) and subjected to an infusion of E. coli endotoxin at 10 μg  ·  kg−1  ·  h−1. Six pigs were given melagatran during the first 3 h of the 6‐h endotoxaemic period. Nine controls were given the corresponding volume of saline instead of melagatran. Specimens from the liver and the left lung were taken for light microscopy post mortem.Results: The endotoxin‐induced increase in pulmonary capillary wedge pressure and drop in platelet count were significantly less pronounced in the melagatran‐treated pigs. Deposits of pulmonary fibrin were significantly reduced in the melagatran group, without improving oxygenation. Light microscopy revealed no hepatic fibrin in the pigs treated with melagatran in contrast to the endotoxaemic controls. Hepatic neutrophil accumulation was reduced in the melagatran group as compared to controls. Hepatocellular degeneration and plasma levels of tumour necrosis factor α (TNFα) and bilirubin were of the same magnitude in both groups.Conclusion: Melagatran reduced pulmonary capillary wedge pressure, a retrograde reflection of the left ventricular end‐diastolic filling pressure, and also pulmonary stasis in pigs subjected to endotoxaemic challenge. Pulmonary and hepatic fibrin depositions were reduced, but PaO2 levels or liver function markers were not affected by melagatran during the early phase of endotoxaemia. Obstruction of the intrahepatic bile ducts, by fibrin depositions, is not responsible for reduced excretion of conjugated bilirubin during endotoxaemia. The beneficial effects of melagatran during endotoxaemia were not due to any reduction of plasma TNFα.
Continuous epidural analgesia with bupivacaine‐fentanyl versus patient‐controlled analgesia with i.v. morphine for postoperative pain relief after knee ligament surgery Note
Authors: Silvasti M. , Pitkänen M. 
Published: March 2003

Background: Both epidural analgesia and intravenous patient‐controlled analgesia (PCA) have been found efficacious after various types of surgery. We compared the efficacy, safety, side effects and patient satisfaction of these methods in a randomized double‐blind fashion after elective anterior cruciate ligament reconstruction of the knee.Methods: Fifty‐six patients had an epidural catheter placed at the L2–L3 interspace. Spinal anaesthesia with 15 mg of plain bupivacaine 5 mg/ml was performed at the L3–L4 interspace. After surgery the patients were randomly divided into three groups: 19 received a continuous epidural infusion with bupivacaine 1 mg/ml and fentanyl 10 mg/ml (F10), 19 patients received bupivacaine 1 mg/ml and fentanyl 5 μg/ml (F5) and 18 patients received saline (S). The rate of the epidural infusions was 0.1 ml kg−1h−1. Each patient could also use an intravenous (i.v.) PCA device with 40 μg/kg bolus doses of morphine with a lockout period of 10 min and a maximum dose 240 μg kg−1h−1. At the end of surgery ketoprofen 100 mg i.v. was given and continued orally three times a day. Patients were assessed for pain with a visual analogue scale (VAS) at rest and during activity, side effects and satisfaction at 3, 9 and 20 h.Results: Both epidural infusions (F10, F5) provided better analgesia than epidural saline plus i.v. PCA (S) (P<0.05). There was slightly less nausea in the S group (NS). In spite of the difference in the quality of pain relief, there was no difference between the groups in patient satisfaction regarding analgesic therapy.Conclusion: Epidural infusion of fentanyl (1 μg kg−1h−1 or 0.5 μg kg−1h−1) and bupivacaine (0.1 mg kg−1h−1) provided better pain relief but more side effects than intravenous morphine patient‐controlled analgesia after knee ligament surgery. Almost all patients in all groups were satisfied with their pain relief.
Note
Patient‐controlled versus nurse‐controlled pain treatment after coronary artery bypass surgery
Authors: Pettersson P. , Anjou Lindskog E. , Öwall A. 
Published: March 2003

Background: Pain after coronary artery bypass surgery persists for several days. A continuous intravenous infusion of an opioid adequately accomplishes good pain control in the intensive care unit, but it is often not suitable on the ordinary ward. Patient‐controlled analgesia (PCA) with intermittent injections delivered by one of the new devices now available could be an alternative to conventional nurse‐controlled analgesia (NCA) based on intermittent injections. The aim was to compare these two techniques with respect to efficacy and the amount of opioid used.Methods: Forty‐eight patients randomly received PCA or NCA with ketobemidone following extubation after coronary artery bypass grafting. Drug consumption, pain assessment with the visual analogue score (VAS) and possible side effects were evaluated from extubation to the end of the second postoperative day.Results: On the day of surgery the VAS scores did not differ between the groups. From the afternoon of the first postoperative day the VAS scores were higher in the NCA group with mean values at 3–4 out of 10 as compared with mean values around 2 in the PCA group (P<0.01). During the study period the patients in the PCA group received more ketobemidone as compared with the NCA group, 61.9±24.0 mg and 36.3±20.2 mg, respectively (P<0.01). Additional oral analgesics were used in 12 of the patients in the NCA group compared with none in the PCA group. The few side effects reported were equally distributed between the two groups.Conclusion: PCA treatment after coronary artery bypass surgery resulted in better pain treatment and the use of more opioid without an increase in side effects compared with traditional NCA treatment.
Pain intensity and pain relief after surgery
Authors: Klopfenstein C. E. , Herrmann F. R. , Mamie C. , Van Gessel E. , Forster A. 
Published: March 2003

Background: Postoperative pain remains a problem for many patients. One of the reasons could lie in the insufficient evaluation of pain and analgesia. This study was designed to obtain more insight in the performance of nurses and physicians in evaluating patients’ postoperative pain and pain relief.Methods: Forty patients hospitalised in one surgical unit and the 8 nurses and the 2 surgical residents in charge of this unit were investigated. Patients were asked to assess on a visual analogue scale the intensity of their pain and their pain relief at rest, on coughing and globally since the operation, on the first and second postoperative days and the day before hospital discharge. Separately, the nurses and the physicians were asked to evaluate the pain intensity and the pain relief for each patient involved. A MANOVA and a multiple comparisons test with Bonferroni adjustment were used.Results: At rest, only nurses underestimated pain intensity on the day before hospital discharge. On coughing, physicians underestimated pain intensity in all 3 assessments, whereas nurses only in the 3rd assessment (on the day before hospital discharge). Globally, physicians underestimated pain intensity in all 3 assessments, nurses in the 2nd and the 3rd assessment. Only physicians overestimated pain relief on coughing on the day before hospital discharge and globally in all 3 assessments. Surprisingly, the pain scores rated by the patients before hospital discharge were high.Conclusion: The results of this survey suggest that assessment of pain and pain relief is inadequately done by both physicians and nurses. This emphasises the importance of a better training, and a systematic assessment of pain intensity and pain relief.
Nitric oxide does not play a major role in the regulation of systemic hemodynamic responses to acute normovolemic hemodilution
Authors: Hirose Y. , Kimura H. , Kitahata H. , Kawahito S. , Oshita S. 
Published: March 2003

Background: The mechanisms of cardiovascular changes following acute normovolemic hemodilution (ANH) have not been fully elucidated. We tested the hypothesis that inhibition of nitric oxide synthesis attenuates ANH‐induced cardiovascular responses.Methods: We observed the effects of Nω‐nitro‐L‐arginine methyl ester (L‐NAME) pretreatment on ANH‐induced cardiovascular responses and compared these effects with those elicited by phenylephrine (PHE). Twenty dogs anesthetized with isoflurane were divided into two groups: one group was pretreated with L‐NAME and the other with PHE. Both groups were normovolemically hemodiluted using 6% hydroxyethyl starch to reduce the hemoglobin concentration to approximately 50% of the pretreatment value.Results: Pretreatment with either L‐NAME or PHE caused a significant increase in mean aortic blood pressure (MAP) and systemic vascular resistance (SVR) with a significant decrease in cardiac output (CO) and stroke volume (SV). However, no remarkable differences in these variables were seen between groups. In both groups ANH produced increases in heart rate, CO, SV, and maximal left ventricular dP/dt with a significant decrease in SVR. No significant differences in these variables were apparent after ANH except that MAP was decreased in the PHE group but not in the L‐NAME group.Conclusion: Our results suggest that nitric oxide does not play a major role in mediation or modulation of the systemic vascular responses to ANH.
Cost comparison between three different general anaesthetic techniques for elective arthroscopy of the knee
Authors: Heidvall M. , Hein A. , Davidson S. , Jakobsson J. 
Published: March 2003

Introduction:We compared three anaesthetic techniques for elective knee arthroscopy with special reference to cost‐effectiveness.Method:Seventy‐five ASA I–II patients having elective arthroscopy of the knee joint were randomised to receive an anaesthetic technique based on propofol, fentanyl for induction followed by sevoflurane in oxygen:nitrous oxide (1:2 l/min) for maintenance of one of two intravenous techniques: propofol alfentanil or propofol‐remifentanil infusions in combination with oxygen in air.Results: All patients had an uncomplicated course. No differences were seen with regard to emergence, postoperative pain or emesis or time to discharge. The anaesthetic technique based on sevoflurane was associated with the lowest cost US$ 14.7 as compared to US$ 18 for the propfol/alfentanil and US$ 19.9 for the propofol/remifentanil technique, including both cost for wastage as well as premedication and other fixed drug costs. Looking only at the anaesthetic drugs consumed, the cost per minute was US$ 0.56 for sevoflurane/nitrous oxide as compared to US$ 0.68 and 0.63 per minute for the propofol/alfentanil and proprofol/remifentanil, respectively. When the cost for wastage was taken into account, the difference in mean anaesthetic drug cost was more pronounced: the sevoflurane anaesthetic technique US$ 0.58, the propofol/alfentanil US$ 0.74 and the propofol/remifentanil US$ 0.84 per minute respectively.Conclusion: From a cost‐minimisation point of view, anaesthesia based on sevoflurane in oxygen:nitrous oxide is the technique of choice.
Nerve stimulation at 0.15 Hz when compared to 0.1 Hz speeds the onset of action of cisatracurium and rocuronium
Authors: Eikermann M. , Peters J. 
Published: March 2003

Background: Onset time of specific non‐depolarizing muscle relaxants (NDMR), as reported in the literature, varies widely. To test the suggestion of a consensus panel (Copenhagen Consensus Conference 1996) that onset time in muscle relaxant studies depends on stimulation frequency, even in the low frequency range, we examined the onset time of cisatracurium and rocuronium by parallel ulnar nerve stimulation in both upper extremities at 0.1 Hz and 0.15 Hz.Methods: Thirty patients (ASA class I and II) were included. Onset of action following the administration of 2×ED90 of cisatracurium (0.092 mg · kg−1) or rocuronium (0.74 mg · kg−1) was measured by quantifying the evoked response of the adductor pollicis muscles using mechanomyography. Single twitch stimulations were applied simultaneously to the ulnar nerves of both forearms using a 0.1 Hz and 0.15 Hz stimulation frequency, respectively.Results: Both relaxants showed a significantly (P<0.01) shorter onset time with 0.15 Hz compared to 0.1 Hz stimulation (cisatracurium: 186±50 s vs. 233±59 s, rocuronium: 73±14 s vs. 99±23 s; x?±SD).Conclusions: Onset time of NDMR depends on the stimulation frequency, even in the low frequency range. When comparing onset studies, the reader must also compare the stimulation rates used by the investigators. We recommend the use of 0.1 Hz single twitch nerve stimulation frequency as the standard for studies of onset profile of NDMR.
Coronary and systemic hemodynamic effects of clevidipine, an ultra‐short‐acting calcium antagonist, for treatment of hypertension after coronary artery surgery
Authors: Kieler‐Jensen N. , Jolin‐Mellgård Å. , Nordlander M. , Ricksten S.‐E. 
Published: March 2003

Background: The aim was to evaluate the use of clevidipine, a new vascular selective, ultra‐short‐acting calcium antagonist for blood pressure control after coronary artery bypass grafting (CABG).Methods: The effects of clevidipine on central hemodynamics, myocardial blood flow and metabolism were studied at two different phases after CABG. In phase 1 (n=13), the hypertensive phase, the effects of clevidipine were compared to those of sodium nitroprusside (SNP) when used to control postoperative hypertension. In phase 2 (n=9), the normotensive phase, a clevidipine dose‐response relationship was established.Results: At a target mean arterial pressure (MAP) of 75 mmHg, systemic vascular resistance (SVR) and heart rate (HR) were lower, preload, stroke volume (SV) and pulmonary vascular resistance (PVR) were higher, while there were no differences in myocardial lactate metabolism or oxygen extraction with clevidipine compared to SNP. In the normotensive phase, clevidipine induced a dose‐dependent decrease in MAP (−19%), SVR (−27%) and PVR (−15%), accompanied by an increase in SV (10%), but no reflex increase in HR or changes in cardiac preload. Clevidipine caused a direct coronary vasodilation, as indicated by a decrease in myocardial oxygen extraction from 54% to 45%. Myocardial lactate metabolism was unaffected by clevidipine. The blood clearance of clevidipine was 0.05 l  ·  min−1  ·  kg−1, the volume of distribution at steady state was 0.08 l  ·  kg−1 and the initial and terminal half‐lives were <1 min and 4 min, respectively.Conclusions: Clevidipine rapidly reduced MAP and induced a systemic, pulmonary and coronary vasodilation with no effect on venous capacitance vessels or HR. Clevidipine caused no adverse effects on myocardial lactate metabolism. Clevidipine thus appears suitable to control blood pressure after CABG.
Estimation of cardiac preload changes by systolic pressure variation in pigs undergoing pneumoperitoneum
Authors: Tournadre J. P. , Allaouchiche B. , Cayrel V. , Mathon L. , Chassard D. 
Published: March 2003

Background: Variations in systolic pressure arterial waveform (SPV) and its component have been shown to be a reasonable indicator of left ventricular preload. Creation of a pneumoperitoneum (PMOP) by insufflation of CO2 increases intrathoracic pressure, leading to overestimation of preload as assessed by pressure methods. The purpose of this study was to compare SPV with other standard methods in anaesthetized pigs.Methods: We measured SPV and its DeltaDown component (ΔDown), pulmonary artery occlusion pressure (PAOP) and left ventricular short‐axis cross‐sectional area using transthoracic echocardiography (TTE) in 7 pigs, at baseline, after 12 mmHg PMOP and after an intravascular load with 10 ml/kg hydroxylethylstarch (HES).Results: PMOP increased SPV from 12.9±4.9 to 16.9±5.5 mmHg (P<0.05) and decreased pulmonary compliance, with no change in PAOP or end‐diastolic area assesssed by TTE. Intravascular volume loading significantly decreased SPV from 16.9±5.5 to 11.2±4.9 mmHg and ΔDown from 9.9±7.1 to 5.2±4.5 (P<0.05), and increased PAOP and end‐diastolic area. Significant correlation between changes in ΔDown and EDA was noted following HES (r=0.78, P<0.05).Conclusion: In anaesthetized pigs, the creation of a PMOP alters SPV, likely by decreasing lung compliance. Once PMOP is established, changes in cardiac preload could be estimated by SPV analysis.