bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of sustained pressure application on compliance and blood gases in healthy porcine lungs
Authors: Markström A. , Hedlund A. , Sjöstrand U. , Nordgren A. , Lichtwarck‐Aschoff M. 
Published: March 2003

Background: Short periods of sustained increase in airway pressures (Pressup) are believed to re‐open lung areas that collapsed upon induction of anaesthesia. Recruitment of alveolar surface is usually assessed in terms of changes in the pressure–volume (PV) curve. The purpose of this study was to analyse PV‐curves before and after a Pressup and to ascertain whether such changes are compatible with the concept of recruitment of lung volume.Methods: During ketamine anaesthesia, 12 healthy piglets were subjected to a Pressup with end‐expiratory pressure (PEEP) of 12 cmH2O and end‐inspiratory pressure of 40 cmH2O. Before and after Pressup, PV‐curves were obtained from a slow insufflation of 630 ml at zero PEEP (ZEEP).Results: Compliance was non‐linear both before and after Pressup increasing up to 300 ml and sharply decreasing thereafter. After Pressup, the entire compliance curve was shifted to a higher absolute level. Up to 100 ml and a pressure level corresponding to the lower inflection point on the PV‐curve (LIP), compliance was higher before Pressup. No effects on blood gases could be observed.Conclusion: If the similar shape of the compliance curve corresponds to a similar chain of re‐opening and overdistension events, this would imply that all volume gained by Pressup is lost within 10 min, without explaining the higher absolute compliance following Pressup. We speculate that a) re‐opening of rapidly collapsing small airways determines the initial compliance increase; b) the lower compliance after Pressup until LIP indicates reduced intratidal re‐opening of lung regions; and c) changes in bronchomotor tone induced by Pressup raise the absolute compliance, with a similar scenario of alveolar and small airway recruitment now taking place but at different degrees of airway stiffness.
Effects of the endothelin receptor antagonist bosentan on cardiac performance during porcine endotoxin shock
Authors: Wanecek M. , Weitzberg E. , Alving K. , Rudehill A. , Oldner A. 
Published: March 2003

Background: Cardiac dysfunction during septic shock is well described but the underlying mechanisms still remain to be resolved. This study was conducted to elucidate the involvement of endothelin in cardiac function during endotoxin shock by the use of endothelin receptor antagonism.Methods: Anaesthetised and haemodynamically stable landrace pigs received the nonpeptide mixed endothelin receptor antagonist bosentan, two hours after onset of endotoxaemia (n=7). Cardiopulmonary vascular changes, including cardiac index, stroke work index, coronary artery blood flow, rate of change of left ventricular pressure (dp/dt), and arterial and coronary sinus plasma levels of endothelin‐1‐like immunoreactivity were compared to a control group only receiving endotoxin (n=7).Results: Plasma endothelin‐1‐like immunoreactivity increased threefold in the control group. Bosentan effectively counteracted the endotoxin induced decrease in cardiac index. This was accompanied by a significant reduction of both right and left ventricular afterload. In addition, coronary artery blood flow increased and coronary vascular resistance decreased compared to controls. Dp/dt remained unaffected by endothelin receptor antagonism. A further increase in plasma endothelin‐1‐like immunoreactivity was seen in response to bosentan.Conclusion: These results indicate that the increased endothelin production during endotoxaemia contributes to a depressed cardiac performance and that endothelin receptor antagonism may counteract this development. Possible mechanisms for the improved cardiac performance include both a reduction of afterload and enhanced coronary blood flow.
Effect of intravenous prostaglandin E1 on pial vessel diameters and intracranial pressure in rabbits
Authors: Miyabe M. , Fukuda T. , Saito S. , Tajima K. , Toyooka H. 
Published: March 2003

Background: The main advantages of prostaglandin E1 (PGE1) for induced hypotension during neurosurgery include a rapid onset of action, a quick recovery from hypotension, lack of toxicity, maintenance of adequate perfusion to vital organs, and maintenance of cerebral blood flow reactivity to carbon dioxide during hypotension. However, there is no report that shows the effect of PGE1 on cerebral microvessel diameter and only a few data are available that show the effect of PGE1 on intracranial pressure. The aim of this study was to measure cerebral arteriole and venule diameters and intracranial pressure (ICP) during PGE1‐induced hypotension to evaluate whether PGE1 is suitable for neuroanesthesia.Methods: We measured the effects of 0.1, 0.3, 1.0, 3.0, and 10.0 μg  ·  kg−1  ·  min−1 of intravenous PGE1 on mean arterial pressure (MAP), cerebral arteriole and venule diameters and ICP in anesthetized rabbits.Results: MAP decreased statistically significantly from baseline at the infusion rates of 1.0, 3.0, and 10.0 μg  ·  kg−1  ·  ml−1. Arteriole diameter increased significantly from the baseline at the infusion rate of 10.0 μg  ·  kg−1  ·  ml−1 (18% from control). Venule diameter did not change from baseline value at any infusion rate. ICP did not change from baseline value at any infusion rate.Conclusion: We conclude that PGE1 might be a suitable drug for induced hypotension in neurosurgery from the viewpoint of its small effect on the cerebral microvessels and ICP.
Plasma concentrations of ropivacaine following a single‐shot caudal block of 1, 2 or 3 mg/kg in children
Authors: Bösenberg A. T. , Thomas J. , Lopez T. , Huledal G. , Jeppsson L. , Larsson L. E. 
Published: March 2003

Background: For documenting the properties of ropivacaine used for regional anaesthesia in children, the relationship between dose and resulting systemic exposure is essential. The aim of this pharmacokinetic part of a randomised, multicentre, double‐blind study was to determine the free and total plasma levels of ropivacaine in children aged between 4 and 12 years following a single‐shot caudal dose of 1, 2 or 3 mg/kg of ropivacaine for postoperative pain management.Method: Following induction of a standardised general anaesthetic (halothane; nitrous oxide: oxygen 60:40), a caudal block using 1 ml/kg ropivacaine in concentrations of 1, 2 or 3 mg/ml was performed in 43 ASA I children (body weight 12–25 kg) scheduled for elective inguinal surgery. Blood samples were collected prior to and 15, 30, 45, 60 and 240 min after placement of the caudal block for determination of total and free ropivacaine plasma concentrations.Results: The peak plasma concentration of total ropivacaine, reached within 15–241 min after the block, increased in proportion to dose, with mean values at 0.27, 0.64 and 0.90 mg/l following 1, 2 and 3 mg/kg respectively. The peak plasma level of free ropivacaine also increased in a dose‐proportional manner, with mean levels at 0.014, 0.030 and 0.042 mg/l. The highest individual peak plasma level of free ropivacaine was 0.070 mg/l, well below the threshold levels of CNS toxicity described in adults. No clinical signs of systemic toxicity were observed.Conclusion: Following single‐shot caudal doses of 1–3 mg/kg in children up to 25 kg and aged between 4 and 12 years, plasma levels of free ropivacaine increase in proportion to dose and all were shown to be within safe limits.
Sympathetic nervous activation following subarachnoid hemorrhage: Influence of intravenous clonidine
Authors: Lambert G. , Naredi S. , Edén E. , Rydenhag B. , Friberg P. 
Published: March 2003

Background: Subarachnoid hemorrhage is often accompanied by systemic complications and cerebral vasospasm. Elevated levels of circulating catecholamines may be involved in the pathophysiology behind these events. The alpha‐2‐agonist clonidine inhibits sympathetic outflow by a central mechanism. Unrestricted sympathoexcitation may be detrimental and administration of clonidine may be beneficial in these patients.Methods: Using isotope dilution methodology, norepinephrine kinetic determinations, comprising determination of arterial norepinephrine concentration and rates of norepinephrine spillover to and removal, or clearance, from plasma, were performed on three occasions during the first week after subarachnoid hemorrhage in 25 patients. Eleven of these patients received clonidine (continuous i.v. infusion 5.8 ± 0.7 µg·kg−1·24 h−1) and the remainder, standard therapy. Initial results were compared with 17 healthy age‐matched subjects and eight patients suffering from severe traumatic brain injury without traumatic subarachnoid hemorrhage.Results: Subarachnoid hemorrhage patients exhibited markedly elevated arterial plasma norepinephrine concentrations [3.74 ± 0.48, P < 0.001 vs. healthy subjects (1.59 ± 0.11 nmol/L) and P < 0.05 vs. head trauma patients (1.94 ± 0.29 nmol/L)]. The rate of clearance of norepinephrine from plasma in the subarachnoid patients was also significantly greater than that observed in the healthy subjects (2.66 ± 0.15 vs. 2.14 ± 0.15 L/min, P < 0.05) and the head trauma patients (2.00 ± 0.12 L/min, P < 0.05). Compared with both control groups, on admission the rate of spillover of norepinephrine to plasma following subarachnoid hemorrhage was markedly elevated (9.11 ± 1.12, P < 0.001). Clonidine treatment (continuous i.v. infusion 5.8 ± 0.7 µg·kg−1·24 h−1) did not reduce the increased rate of spillover of norepinephrine to plasma following subarachnoid hemorrhage.Conclusion: Sympathetic nervous activity is markedly elevated following subarachnoid bleeding. Clonidine had no effect on the rate of norepinephrine spillover to, or clearance from, plasma in these patients. Clearly, further studies are required to elucidate the mechanisms responsible for generating sympathetic nervous activation following subarachnoid hemorrhage.
Accuracy of radial arterial pressure measurement during surgery under controlled hypotension
Authors: Yazigi A. , Madi‐Jebara S. , Haddad F. , Hayek G. , Jawish D. 
Published: March 2003

Background: Radial arterial pressure underestimates the pressure in the aorta in several clinical situations. A central‐to‐radial pressure gradient was attributed to intense vasodilation. The aim of this study was to evaluate the accuracy of radial pressure monitoring during controlled hypotension achieved with profound arterial vasodilation.Methods: Ten patients with ASA physical status I and II undergoing maxillofacial surgery under general anesthesia were enrolled in this prospective study. Radial and femoral arteries were cannulated and connected to a pressure monitoring system. Controlled hypotension was achieved with an infusion of nicardipine titrated to maintain MAP between 50 and 60 mmHg. Simultaneous radial and femoral systolic, mean and diastolic arterial pressures were recorded before, during and after controlled hypotension. Results were expressed as mean ± SD. Concomitant radial and femoral pressures were compared by a paired Student's test, P < 0.05 being significant.Results: In all, 150 sets of arterial pressures measurement were obtained. There were no statistically significant differences between radial and femoral arterial pressures measured before, during or after controlled hypotension.Conclusion: Radial arterial pressure is an accurate measure of central arterial pressure during controlled hypotension achieved with arterial vasodilation.
Carbon monoxide poisoning − a cause of increased QT dispersion
Authors: Gürkan Y. , Canatay H. , Toprak A. , Ural E. , Toker K. 
Published: March 2003

Background: Carbon monoxide (CO) poisoning is associated with direct cardiovascular toxicity. QT dispersion (QTd) of the ECG is an indirect measure of heterogeneity of ventricular repolarization, which may contribute to ventricular arrhythmias. Our aim was to study QTd in patients with acute CO poisoning.Methods:  CO intoxication was confirmed by arterial blood gas analysis. A control group consisted of age‐ and sex‐matched individuals admitted to the hospital for unrelated clinical conditions. 12‐lead ECG's were recorded on admission and repeated 1 week after discharge from the hospital. QT dispersion was defined as the difference between the greatest and the least QT intervals in any of the 12 leads.Results:  Seventeen intoxicated patients, aged 5–46 years, had mean carboxyhemoglobin levels of 22.5 ± 11.1%. On admission, corrected QT intervals of the intoxicated patients were significantly increased compared to the control group (431 ± 18 ms vs. 404 ± 28 ms, P = 0.008), but not the QT interval (358 ± 25 ms vs. 345 ± 20 ms, P = 0.17). Mean QTd and cQTd values (46 ± 15 ms and 62 ± 13 ms) of the intoxicated patients were significantly increased compared to the control group (17 ± 4 ms and 33 ± 15 ms, P < 0.0001 for both). Both QTd and cQTd decreased significantly after discharge from the hospital (P = 0.0001).Conclusion:  Although QT dispersion increased in patients with CO poisoning, none of ECG's showed ventricular arrhythmia. Increased QTd in the absence of QT interval prolongation may have a lowered arrhythmogenic potential of CO poisoning.
Parenteral ketoprofen for pain management after adenoidectomy: comparison of intravenous and intramuscular routes of administration
Authors: Tuomilehto H. , Kokki H. 
Published: March 2003

Background: Different parenteral routes of administration of NSAIDs such as ketoprofen have not been properly compared in children. This study was designed to compare the analgesic efficacy of intravenous and intramuscular ketoprofen for pain management in children after day‐case adenoidectomy.Methods: A total of 120 children, aged 1–9 years, who were scheduled to undergo adenoidectomy, were randomized to receive ketoprofen 2 mg/kg either intravenously with intramuscular placebo (n = 40) or ketoprofen 2 mg/kg intramuscularly with intravenous placebo (n = 40), or both intravenous and intramuscular placebo (n = 40) at induction of anesthesia. The study design was prospective and double‐blind with parallel groups. Pain was assessed at rest and during swallowing using the Maunuksela pain scale during 3 h after surgery, and fentanyl i.v. was given for rescue analgesia.Results: Children in the Placebo group needed significantly more doses of fentanyl (72 doses) than either children in the intravenous group (47 doses) or children in the intramuscular group (51 doses) (P = 0.021). In addition, a higher proportion of children in the Placebo group than in the two ketoprofen groups (P = 0.03) demanded rescue analgesic. No difference in the need for rescue analgesia or in pain scores was found between the two ketoprofen groups. Children in the intravenous group had less pain than children in the Placebo group. The difference was significant during swallowing at 1 h after surgery (P = 0.046) and for the worst pain observed during swallowing for 3 h after surgery (P = 0.022). There were no differences between the three groups with respect to operation times, amount of perioperative bleeding, or rate or extent of adverse events.Conclusion: The efficacy of intravenous and intramuscular ketoprofen was similar, and they both differed from placebo.
Anatomical study applied to anesthetic block technique of the superior laryngeal nerve
Authors: Furlan J. C. 
Published: March 2003

Background: The topography of the internal branch of the superior laryngeal nerve (ibSLN) was prospectively studied to evaluate the greater horn of the hyoid bone (ghHB) and the incisura of the thyroid cartilage (iTC) as anatomical repairs in laryngeal anesthetic block. Factors such as gender, ethnicity and side of the neck were also analyzed concerning their influence in the ibSLN position.Methods: One hundred neck dissections were performed in 50 human cadavers bilaterally identifying the ibSLN, the ghHB and iTC. The distance between the ghHB and ibSLN in the cranio‐caudal direction (dHB), and the distance between the iTC and the ipsilateral thyrohyoid membrane ostium (dTC) were measured. Furthermore, the results were statistically analyzed according to ethnicity, gender and side of the neck.Results: The ibSLN was juxtaposed to the apex ghBH in 31 out of 100 dissections. The mean dHB was 2.4 mm, and mean dTC was 33.4 mm. The statistical analysis did not identify any significant difference regarding those distances between the groups in terms of ethnicity, gender and side of the neck.Conclusion: The ibSLN was often dissected very close to the ghHB, and this result was not influenced by any factor studied. Therefore, the ghHB can be considered a good anatomical repair to localize the ibSLN in the local block of the larynx. Furthermore, the dTC could frequently be reached by routinely used nerve block needle. However, a few anatomical variations may occur, resulting in a low failure rate of this anesthetic procedure.
Superior prolonged antiemetic prophylaxis with a four‐drug multimodal regimen – comparison with propofol or placebo
Authors: Hammas B. , Thörn S‐E. , Wattwil M. 
Published: March 2003

Background:  The purpose of this study was to compare the effects of a low‐dose propofol infusion with a four‐drug multimodal regimen for prophylaxis of postoperative nausea and vomiting (PONV).Methods: PONV was studied in two patient groups with a known high incidence. Through a stratified randomization, 60 patients undergoing breast surgery and 120 patients undergoing abdominal surgery were randomized to three groups of equal size: the propofol group (P), the multidrug group (M) and the control group (C). All patients received general anesthesia, induction with propofol and maintenance with sevoflurane. After induction, patients in the P group received a continuous infusion of propofol 1 mg/kg/h during the operation and the first 4 postoperative h. Patients in the M group received dexamethasone 4 mg and three antiemetics, ondansetron 4 mg, droperidol 1.25 mg and metoclopramide 10 mg i.v. In the control group no prophylaxis was given. Nausea and pain were evaluated by incidence and a visual analog scale (0–10 cm). All emetic episodes were noted by the staff during the first 4 h and by the patients during the next 20 h.Results: The overall incidence of PONV during the first 24 h postoperatively was significantly lower in the M group (24%) than in the P group (49%) (P<0.01) or the C group (70%) (P<0.001). The incidence of PONV increased significantly both in patients undergoing breast surgery and abdominal surgery after termination of propofol. The number of patients who vomited was significantly lower in the M group, both in breast surgery patients (5%) and abdominal surgery patients (3%) compared to patients in the propofol groups (breast 16% NS; abdominal 29%, P<0.05) and in the control groups (breast 37%, P<0.01; abdominal 29%, P<0.01).Conclusion: The incidence of PONV is very high in patients undergoing breast and abdominal surgery. In the present study antiemetic prophylaxis with a combination of droperidol, ondansetron, metoclopramide and dexamethasone was more effective in preventing PONV, especially vomiting, than a postoperative low‐dose infusion of propofol, which had a short lasting effect.
Evaluation of remifentanil as single drug for awake fiberoptic intubation
Authors: Puchner W. , Egger P. , Pühringer F. , Löckinger A. , Obwegeser J. , Gombotz H. 
Published: March 2003

Background:  Awake fiberoptic intubation is the standard of care for difficult airway management. Quality and success of this technique depend on the experience of the intubating physician and the proper preparation of the patient. The aim of this study was to compare remifentanil (R) as single agent to the combination of fentanyl (F) and midazolam (M), which have been the drugs for analgesia and sedation for this procedure.Methods:  Seventy‐four adult patients requiring nasotracheal intubation were randomly assigned to one of two groups. In group I, (n=37) R was administered in incremental dosages (0.1–0.25–0.5 µg/kg/min) by an infusion pump according to comfort, level of sedation and respiratory depression. In group II, (n=37) analgesia and sedation was achieved by F 1.5 µg/kg and doses of between 1 and 10 mg M, titrated to the individual needs. Patient reactions like grimacing, movement and coughing during intubation were assessed, as well as patient recall of the procedure. Haemodynamic and respiratory parameters were continuously recorded.Results:  Group I patients better tolerated nasal tube passage (P<0.001) and laryngeal tube advancement (P<0.001) than group II. Remifentanil better suppressed hemodynamic response to nasal intubation (P<0.001). No significant difference in respiratory data was recorded. In group I more recall of the procedure was observed (six vs. zero patients, P<0.05).Conclusion:  Remifentanil in high doses, as the single agent for patient preparation for awake fiberoptic intubation seems to improve intubating conditions, quality and reliability of the procedure. However, a higher incidence of recall is to be expected.
Development and evaluation of a video program for presentation prior to elective cardiac surgery
Authors: Roth‐Isigkeit A. , Ocklitz E. , Brückner S. , Ros A. , Dibbelt L. , Friedrich H.‐J. , Gehring H. , Schmucker P. 
Published: March 2003

Background:The objective of the present study was to develop and evaluate the effects of a preparatory videotape on endocrine stress responses of patients prior to cardiac surgery and to analyze patient acceptance of this video for preoperative preparation.Methods:101 male patients prior to elective cardiac surgery were enrolled into the study. On the day before surgery, patients were assigned to one of the following groups: group 1 (n = 51) saw a video with realistic information about the upcoming perioperative procedure, and group 2 (n = 50) saw a video of the same length without surgery‐related information. Venous blood was sampled before and 15 min after the video presentation. On the second postoperative day, patients filled in a questionnaire concerning their experiences of having preoperatively watched the video.Results:After viewing the video, blood levels of cortisol, adrenocorticotropic hormone (ACTH), beta‐endorphin, prolactin, epinephrine and norepinephrine in patients of group 1 were not significantly different compared to values measured before the video presentation. In patients of group 2, blood levels of cortisol, ACTH, prolactin and norepinephrine were significantly lower after video presentation compared to values obtained before the video. Patients of group 1 (compared to group 2) were significantly more often of the opinion that the video had helped in the preparation for surgery, and that they would like to repeat this adjunct preoperative video preparation in another similar situation.Conclusion:We conclude from our results that (i); cardiac surgical patients prefer preoperatively an adjunct surgery‐related video preparation to a non‐specific video presentation, and that (ii); preoperative preparation with realistic information about the upcoming medical procedure in patients undergoing cardiac surgery does not lead to an increase in endocrine stress hormone levels.