bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of intrathecally administered dexmedetomidine, MPV‐2426 and tizanidine on EMG in rats
Authors: TALKE P. , Xu M. , Paloheimo M. , Kalso E. 
Published: December 2004

Background: When administered intrathecally, alpha‐2 adrenergic agonists produce spinally mediated antinociception, but also rapidly redistribute to supraspinal sites. This investigation the compared EMG effects of intrathecally administered dexmedetomidine, MPV‐2426 (fadolmidine), and tizanidine in Sprague‐Dawley rats, which has not been previously described.Methods: We studied electromyographic (EMG) responses of the head and gastrocnemius muscles, antinociception using the tail‐flick test, and sedation by using observer assessment. Saline, dexmedetomidine (0.5 µg, 2.5 µg and 12.5 µg), MPV‐2426 (2 µg, 10 µg and 50 µg) and tizanidine (2 µg, 10 µg and 50 µg) were administered intrathecally.Results: Tizanidine 50 µg, MPV‐2426 10 µg and 50 µg, and dexmedetomidine 2.5 µg and 12.5 µg, decreased EMG activity (P < 0.005). Dexmedetomidine 12.5 µg, MPV‐2426 50 µg, and tizanidine 10 µg and 50 µg increased tail‐flick latencies (P < 0.01). Dexmedetomidine alone significantly increased the magnitude of observer‐assessed sedation (P < 0.0001).Conclusion: We conclude that in rats, intrathecally administered dexmedetomidine, MPV‐2426 and tizanidine have dose‐dependent effects on EMG. At antinociceptive doses, the EMG effects of these three alpha‐2 adrenergic agonists differ (dexmedetomidine > MPV‐2426 > tizanidine).
Catecholamine release during laparoscopic fundoplication with high and low doses of remifentanil
Authors: Myre K. , RÆder J. , Rostrup M. , Buanes T. , Stokland O. 
Published: December 2004

Background:  Reports on stress responses to laparoscopic surgery have been conflicting. Depth of anesthesia may influence the neuro‐hormonal release, including catecholamines. Opioids depress general sympathetic activation in a dose‐dependent manner. We investigated the hypothesis that remifentanil would depress the catecholamine response to pneumoperitoneum and laparoscopic surgery differently with a high dose (HD) compared with a low dose (LD).Methods:  In a randomized, prospective study we investigated 18 ASA I–II patients undergoing laparoscopic fundoplication with an intra‐abdominal pressure of 12 mmHg. The patients were randomized to receive either a LD (0.13 μg kg−1.min−1) or HD (0.39 μg kg−1.min−1) of remifentanil with a target‐controlled infusion (TCI) technique. Bispectral index of EEG (BIS) was maintained at 40–55 by propofol delivered by a TCI system. Arterial catecholamines were analyzed at different times during the procedure.Results:  Norepinephrine increased equally in both groups during pneumoperitoneum and surgical intervention. Epinephrine stayed low in the HD‐group, while increasing during surgery in the LD‐group.Conclusion:  High dose of remifentanil depressed the epinephrine response to pneumoperitoneum and surgery, indicating no general activation of the sympathetic nervous system. Neither a LD nor HD of remifentanil depressed the norepinephrine response during pneumoperitoneum. This suggests a centrally independent release of norepinephrine.
Hyperoxia and the cerebral hemodynamic responses to moderate hyperventilation
Authors: Johnston A. J. , Steiner L. A. , Balestreri M. , Gupta A. K. , Menon D. K. 
Published: December 2004

Background: A reduction in the arterial partial pressure of CO2 (PaCO2) leads to a rapid reduction in cerebral blood flow (CBF). However, despite continuing hypocapnia there is secondary recovery of CBF over time as a result of increases in lactic acid production. Hyperoxia is thought to modulate the production of lactic acid. This study examined the kinetics of middle cerebral artery flow velocity (MCA FV) reduction during hyperventilation, and its modulation by hyperoxia.Methods: Cerebral blood flow was assessed using transcranial Doppler ultrasound in nine healthy, awake human volunteers. Subjects were ventilated, via a mouthpiece, to achieve a stable end‐tidal CO2 (PETCO2). After a 20‐min baseline period the minute volume on the ventilator was passively increased by approximately 20% to reduce PETCO2 by 0.75–1 kPa. After a 10‐min stabilization period the new PETCO2 level was maintained at a constant level for 20 min, and MCA FV recovery was measured during this 20‐min period. Subjects undertook the protocol breathing air and breathing 100% oxygen.Results: The PETCO2 level was (mean ± SD) 4.9 ± 0.4 kPa (normoxia baseline), 4.0 ± 0.3 kPa (normoxia hyperventilation), 4.6 ± 0.4 kPa (hyperoxia baseline) and 3.9 ± 0.4 kPa (hyperoxia hyperventilation). CO2 reactivity was significantly lower with normoxia than hyperoxia (16.5 ± 3.8 vs. 21.2 ± 4.6 % kPa−1; P< 0.05). Middle cerebral artery FV recovery was significantly more rapid with normoxia than hyperoxia (0.23 ± 0.17 vs. 0.08 ± 0.1 % baseline min−1; P< 0.01).Conclusions: Our results suggest that cerebral hemodynamic responses to moderate hyperventilation are different in normoxic and hyperoxic conditions. Clinical assessment of CO2 reactivity and CBF recovery during hyperventilation should take the degree of arterial oxygenation into account.
Nitrous oxide anesthesia and intravitreal gastamponade
Authors: ÅStröm S. , Kjellgren D. , Mönestam E. , Bäcklund U. 
Published: December 2004

The right eye of a 66‐year‐old man was operated with vitrectomy and peeling of an epiretinal membrane. Perioperatively, the eye was filled with 20% SF6 gas to tamponade retinal breaks. Five days later the patient underwent prostatectomy under general anesthesia using nitrous oxide. Postoperatively the eye had no light perception as a result of ischemic retinopathy.The movement of nitrous oxide into gas‐containing spaces in the body has been known for a long time. The use of nitrous oxide in patients with intravitreal gas will elevate the intraocular pressure with risk for closure of the central retinal artery. The present case report highlights the problems that can occur when preoperative assessment is carried out a long time before surgery.
Randomized, double‐blind, placebo‐controlled study of the effect of rectal paracetamol on morphine consumption after abdominal hysterectomy
Authors: Kvalsvik O. , Borchgrevink P. C. , Hagen L. , Dale O. 
Published: December 2004

Background: Paracetamol is widely used for postoperative analgesia. The effect is well documented in minor and moderate extensive surgery, but the effect of paracetamol as an adjunct to opioids in major abdominal surgery is less examined.Methods: Seventy‐eight patients scheduled for elective, benign, and abdominal hysterectomy were included in a prospective, randomized, double‐blind, parallel group, placebo‐controlled study to evaluate the effect of rectal paracetamol in conjunction with intravenous patient‐controlled analgesia (PCA) morphine. Paracetamol 1000 mg or placebo suppositories were given four times daily during the 60‐h study period. I.V. morphine was administered via a PCA pump, limited to maximum of 12 mg h−1. Morphine consumption, pain and morphine‐related adverse effects were recorded. A single‐point analysis was comprised of serum concentrations of paracetamol and morphine.Results: Sixty patients were evaluated: 30 in each group. A 16.6% reduction in overall‐accumulated morphine consumption in the treatment group (99.6 vs. 83.3 mg) was observed (NS, P = 0.06). Mean paracetamol serum concentration was 0.03 mmol l−1 (range: 0.01–0.06 mmol l−1). None of the patients had a paracetamol concentration within the therapeutic range for antipyretic efficacy. Patients with a higher paracetamol concentration had a lower concomitant morphine (P = 0.025) and morphine‐6‐glucuronide (P = 0.014) concentration 2 h after paracetamol administration.Conclusion: A dosage of rectal paracetamol 1000 mg four times daily is too low, as all displayed a suboptimal serum paracetamol concentration. To study the effect of rectal paracetamol after major surgery we have to increase the dose, as higher serum concentrations of paracetamol may cause lower serum concentrations of morphine.
Pretreatment with sufentanil reduces myoclonus after etomidate
Authors: Hueter L. , Schwarzkopf K. , Simon M. , Bredle D. , Fritz H. 
Published: December 2004

Background: Myoclonic movements are a common problem during the induction of general anesthesia with etomidate. We investigated the influence of pretreatment with the opioid sufentanil on the incidence of etomidate‐induced myoclonus.Methods: Forty female patients (ASA physical status I–III) were randomly assigned to receive double‐blinded either 0.3 µg kg−1 of sufentanil or placebo 150 s before the induction of sleep with 0.3 mg kg−1 of etomidate. The patients were observed for any myoclonic movement. Grade of dizziness, breathing frequency, non‐invasive blood pressure and heart rate were measured during the study period.Results: None of the 20 patients receiving sufentanil had myoclonic movements after the administration of etomidate, whereas 16 patients in the placebo group (80%) experienced such movements (P<0.01). No cases of apnoea before induction of sleep were seen in the sufentanil group.Conclusion: Sufentanil 0.3 µg kg−1 is an effective and safe drug to reduce myoclonus after etomidate without causing any harmful side‐effect.
High‐dose glucose‐insulin‐potassium after cardiac surgery: a retrospective analysis of clinical safety issues
Authors: Szabó Z. , Håkanson E. , Maros T. , Svedjeholm R. 
Published: December 2004

Background: Metabolic treatment with insulin or glucose‐insulin‐potassium (GIK) has received attention in association with myocardial infarction, cardiac surgery and critical care. As a result of insulin resistance during neuroendocrine stress, doses of insulin up to 1 IU kg−1 b.w.*h are required to achieve maximal metabolic effects after cardiac surgery. The clinical experience with regard to safety issues of such a high‐dose GIK regime in critically ill patients after cardiac surgery is reported.Methods: Retrospective, observational study involving all patients treated with high‐dose GIK after cardiac surgery during one year in a cardiovascular center at a University Hospital.Results: Eighty‐nine patients out of 854 adult patients undergoing cardiac surgery were treated with high‐dose GIK. Mean age was 69 ± 1 years, Higgins score 5.3 ± 0.3. Preoperatively 31.4% had left ventricular function EF≤0.35 and 32.5% had sustained a myocardial infarct during surgery. Mortality was 5.6% and the average ICU stay was 3.7 ± 0.5 days. The main indication for GIK was intraoperative heart failure (69.7%). The average glucose infusion rate during the first 6 h was 4.22 ± 0.15 and 4.91 ± 0.14 mg kg−1 b.w.*min, respectively, in diabetic and non‐diabetic patients (P = 0.023). Blood glucose and s‐potassium control was acceptable.Conclusions: The high‐dose GIK regime allowed substantial amounts of glucose to be infused both in diabetic and critically ill patients with maintenance of acceptable blood glucose control. Provided careful monitoring, this regime can be safely used in clinical practice and deserves further evaluation for treatment of critically ill patients following cardiac surgery.
Resource use in the ICU: short‐ vs. long‐term patients*
Authors: Stricker K. , Rothen H. U. , Takala J. 
Published: December 2004

Background: Intensive care medicine uses a disproportionate share of medical resources, and little is known about the distribution of resources between different patient groups.Methods: In this prospective observational study, all patients admitted between 1 January 1998 and 31 December 1999 to our medical‐surgical university's ICU were assigned to one of two groups according to length of stay (LOS): patients staying more than 7 days in the unit (group L) and those staying a maximum of 7 days (group S). Resource use was estimated using TISS−28, number of nursing shifts, use of mechanical ventilation, and use of renal replacement therapy. Further, SAPS II and ICU and hospital mortalities were recorded.Results: Of 5481 patients, 583 (10.6%) were in group L and 4898 in group S (89.4%). Patients in group L were more severely sick upon admission than those in group S. Patients in group L stayed a total of 9726 days in the ICU (52.5% of the total LOS). In group L, 69.2% of all shifts with respiratory support and 80.1% of all shifts with renal replacement were used. Further, group L patients consumed 53.4% (909225) of all TISS points provided. The ICU‐mortality rates were 14.4% in group L and 7.2% in group S, and the hospital mortality rates were 19.9% and 9.8%, respectively. A mean of 1898 TISS points was used per patient surviving the hospital stay in group L compared with 190 points in group S.Conclusions: In this university‐based, medical–surgical adult ICU, 11% of all patients stayed more than 7 days in the unit and consumed more than 50% of all resources. Thus, a highly disproportionate amount of resources were used per survivor in group L compared with those in group S.
Preload changes by positive pressure ventilation can be used for assessment of left ventricular systolic function
Authors: Sellgren J. , Söderström S. , Johansson G. , Biber B. , Häggmark S. , Pontén J. 
Published: December 2004

Background: Assessment of preload independent left ventricular function with conductance volumetry is traditionally accomplished by inflating a balloon in the inferior caval vein. Our aim was to investigate if a similar change in preload could be achieved by positive pressure ventilation with large tidal volume.Methods: Conductance volumetry generating left ventricular pressure‐volume loops was used in seven pentobarbital‐anesthetized pigs. Changes in preload recruitable stroke work were studied, comparing the effects of inferior vena cava occlusion (IVCO) or large tidal volume (LTV). Cardiodepression was induced by halothane anesthesia and halothane + phenylephrine, and stimulation by epinephrine infusion.Results: Although the decreasis in left ventricular end diastolic volume was slightly less with LTV (16.5 ± 1.7 ml, mean ± SEM) than with IVCO (22.4 ± 1.7 ml) (P < 0.0001) the PRSW‐slopes showed a high degree of correlation (r=0.80, P < 0.0001). Although peak tracheal pressures increased significantly to 27.8 ± 0.9 mmHg during LTV, esophageal pressures (used as an indicator of pericardial pressure) were unchanged.Conclusions: Positive pressure ventilation with LTV is similar to IVCO in creating transient changes in preload, necessary for assessment of left ventricular systolic function. This observation was valid also during drug‐induced cardiac depression and stimulation. The preload recruitable stroke work used for this validation was shown to be a reliable and stable method.
Rocuronium combined with i.v. lidocaine for rapid tracheal intubation
Authors: Yörükoglu D. , Aşik Ý. , Ökten F. 
Published: December 2004

Background: Rocuronium (ORG 9426) has been shown to have an onset of action more rapid than other nondepolarizing neuromuscular blocking agents and to provide intubating conditions similar to those of succinylcholine 60–90 s after administration. We compared the intubating conditions and hemodynamic changes after the administration of rocuronium 0.6 mg kg−1 and lidocaine 1.5 mg kg−1 with rocuronium alone and succinylcholine 60 and 90 s after administration.Methods: One hundred and twenty‐five adult patients of ASA physical status I or II scheduled for elective surgery were randomly divided into five groups. After propofol administration in all patients, patients in group Su (succinylcholine), group R60 (rocuronium) and group RL60 (rocuronium‐lidocaine) were intubated within 60 s, while groups RL90 and R90 were intubated 90 s after the administration of rocuronium and succinylcholine. Laryngoscopy was performed and intubating conditions were graded by an experienced anesthetist blind to the muscle relaxant allocation.Results: In this study, groups Su, RL60, R90 and RL90 had similar intubation scores, which were significantly better than that for group R60. Heart rate did not increase after intubation in groups Su, RL60 and RL90.Conclusion: The combination of lidocaine (1.5 mg kg−1) and low‐dose rocuronium (0.6 mg kg−1) along with propofol is clinically equivalent to succinylcholine, improves intubating conditions in 60 s and effectively blocks increases in heart rate after intubation.
Inhibitory effects of desflurane and sevoflurane on contractions of isolated gravid rat myometrium under oxytocin stimulation
Authors: Dogru K. , Yildiz K. , Dalgiç H. , Sezer Z. , Yaba G. , Madenoglu H. 
Published: December 2004

Background: We studied the inhibitory effects of desflurane and sevoflurane on oxytocin‐induced contractions of isolated gravid rat myometrium.Methods: Twenty strips were obtained from rats and these were randomly assigned into two groups. The effects of desflurane and sevoflurane were evaluated by treating strips with oxytocin alone 2×10−9 M or with oxytocin after desflurane and sevoflurane at 0.5, 1, and 2 MAC.Results: Oxytocin significantly increased the amplitude and duration of contractions (P< 0.05), but it did not increase the frequency. The duration (84%, 79%), amplitude (90%, 84%) and frequency (88%, 75%) were inhibited at 2 MAC of desflurane and sevoflurane, respectively.Conclusion: These results suggest that the in vitro application of desflurane and sevoflurane similarly inhibit oxytocin‐induced myometrial contractions of gravid rat in a dose‐dependent manner.
Response to the prone position in spontaneously breathing patients with hypoxemic respiratory failure
Authors: Valter C. , Christensen A. M. , Tollund C. , SchØnemann N. K. 
Published: December 2004

Objectives: The prone position is used for intubated patients with adult respiratory distress syndrome (ARDS) and acute lung injury (ALI). The physiological changes associated with the prone position in nonintubated patients may be even more favorable than in intubated patients. We examined the effect of the prone position on arterial blood gases and patient compliance in four awake, nonintubated patients with hypoxemic respiratory failure.Design: We present four consecutive cases of hypoxemic respiratory failure, in which mechanical ventilation was indicated. An attempt was made to avoid assisted ventilation by placing patients in the prone position, while breathing spontaneously. The effect on the clinical condition and the changes in blood gases were registered.Results: We found good patient tolerance. A rapid increase in PaO2 was found, and intubation was avoided in all patients. No significant complications were registered.Conclusion: The prone position may prove beneficial in some cases of hypoxemic respiratory failure, even in awake patients, by avoiding mechanical ventilation and ventilator‐associated complications.
Racemic ketamine does not abolish cerebrovascular autoregulation in the pig
Authors: Schmidt A. , Ryding E. , Åkeson J. 
Published: December 2004

Background: Little is known about the influence of racemic ketamine on autoregulation of cerebral blood flow (CBF), and available reports regarding its influence on cerebral hemodynamics are contradictory. This study was designed to evaluate cerebrovascular responses to changes in the mean arterial pressure (MAP) during ketamine anesthesia.Methods: In eight normoventilated pigs anesthesia was induced with propofol and maintained by i.v. infusion of ketamine (15.0 mg kg−1.h−1) during measurements. The intra‐arterial xenon clearance technique was used to calculate CBF. Balloon‐tipped catheters were introduced in the inferior caval vein and mid‐aorta, and increases or decreases by up to 40% in mean arterial pressure (MAP) in random order were achieved by titrated inflation of these balloon catheters. Cerebral blood flow was determined at each MAP level. Regression coefficients of linear pressure‐flow curves were calculated in all animals.Results: From the mean baseline level (101 mmHg) MAP was reduced by 20% and 40%, and increased by 26% and 43%. The maximal mean increase and decrease in MAP induced a 12% increase and a 15% decrease, respectively, of CBF from the mean baseline level (52.6 ml.100 g−1.min1). The 95% confidence interval (−0.02; 0.38) of the mean regression coefficient of individual pressure‐flow curves does not include the regression coefficient (0.64) of a linear correlation between MAP and CBF including origo (correlation coefficient 0.99), which indicates complete lack of cerebrovascular autoregulation.Conclusions: We conclude that autoregulation of CBF is not abolished during continuous ketamine infusion in normoventilated pigs and that previous divergent conclusions are unlikely to be associated with severe impairment of cerebrovascular autoregulation.
Performance of the rapidly extracted auditory evoked potentials index to detect the recovery and loss of wakefulness in anesthetized and paralyzed patients
Authors: Ge S. J. , Zhuang X. L. , Wang Y. T. , Wang Z. D. , Chen S. L. , Li H. T. 
Published: December 2004

Background: The rapidly extracted auditory evoked potentials index (A‐lineTM ARX Index or AAI) has been proposed as a method to measure the depth of anesthesia. A prospective study was designed to assess the performance of AAI to detect the recovery and loss of wakefulness in anesthetized and paralyzed patients.Methods: Fourteen adult patients undergoing elective surgery were anesthetized with propofol 1.5 mg kg−1, vecuronium 0.1 mg kg−1 and further propofol 1.0 mg kg−1. Wakefulness was measured by the ability of the patient to respond to command using the isolated forearm technique (IFT). After the patient responded, propofol was infused at 10 mg kg−1 · h−1 until wakefulness (responsiveness) was lost. The AAI was recorded continuously throughout the study and analyzed off‐line.Results: The AAI showed a significant difference between the values registered during, 30 s before and 30 s after the recovery, and also between 30 s before and 30 s after the loss of wakefulness. The prediction probability (Pk) values for AAI were 0.786 and 0.864 during the transitions from unresponsiveness to responsiveness and from responsiveness to unresponsiveness. The area under the receiver operating characteristic curve for the responsive and unresponsive values was 0.926 (SE 0.002, 95% CI 0.922–0.931), and the AAI values of approximately 5%, 50% and 95% predicted probability of wakefulness were 19, 29 and 39, respectively.Conclusion: The AAI may be a good predictor of recovery and loss of wakefulness for anesthetized and paralyzed patients.