bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enhancement of intrathecal lidocaine by addition of local and systemic clonidine
Authors: Dobrydnjov I. , Samarütel J. 
Published: March 2003

Background: Enhancement of local anaesthetic‐produced regional blocks by clonidine seems well established. There are insufficient data about dose‐effect relationship of combinations of clonidine with individual agents, efficiency of local versus systemic administration of clonidine, and comparative evaluation of clonidine with vasoconstrictors. Because of unavailability of long‐acting local anaesthetics at the time of study, our aim was to evaluate augmentation of lidocaine spinal block with local or systemic clonidine and to compare the results with the efficacy of intrathecal phenylephrine.Methods: Ninety pts of age 50–72 yrs with ASA 1–4 physical status, scheduled for open prostatectomies, hysterectomies or ostheosynthesis of fractured hip were randomized to one of 6 treatment groups, 15 pts in each. Patients received intrathecally (L3–L4) either 100 mg of plain lidocaine (group L100); or a mixture of lidocaine 40 and 80 mg with clonidine 100 μg (groups L40‐C100 and L80‐C100); or a combination of lidocaine 40 and 80 mg with clonidine 300 μg orally 60 min before spinal puncture (L40‐C300 and L80‐C300). Addition of intrathecal phenylephrine 5 mg to 80 mg of lidocaine was also investigated (L80‐P5).Results: There were no significant intergroup differences concerning demographic data or type of surgery. All operations (duration up to 150 min) were completed without need for analgesic supplementation. The addition of clonidine resulted in a significant reduction of the onset time of spinal block and prolongation of the duration of sensory and motor blocks compared to plain lidocaine or lidocaine with phenylephrine. In spite of the well‐known hypotensive action of α2‐agonists, haemodynamic depression only in group L80‐C300 was significantly more pronounced than in L100 and L80‐P5 groups. The least decrease of BP and minimal need of rescue ephedrine among all patients studied were recorded in the group receiving low dosage of lidocaine with intrathecal clonidine (L40‐C100). Sedation occurred in most patients receiving clonidine.Conclusion: Our results indicate that addition of clonidine to lidocaine, irrespective of the route of administration, prolongs the duration of spinal block and permits a reduction of the lidocaine dose needed for a given duration of block. Addition of phenylephrine results in a less pronounced statistically significant prolongation of anaesthesia. The regression of sensory block before restoration of motor function seems to be a specific (and unfortunate) effect of both clonidine and phenylephrine.
Sameridine – intrathecal injection in the rat
Authors: Karlsten R. , Gordh T. , Kristensen J. D. , Ask A.‐L. , Svensson B. A. 
Published: March 2003

Background: Sameridine is a type of compound with both local anaesthetic and analgesic effects with the clinical intention to be used intrathecally (IT) in order to provide both surgical anaesthesia and prolonged postoperative analgesia. Before new drugs are introduced for clinical use, they must be tested for potential toxic effects.Methods: In the present study sameridine (5 or 10 mg/ml), bupivacaine (5 mg/ml) or saline (9 mg/ml) was injected intrathecally in rats twice, daily (at 07:00 and 19:00), 5 days a week for 2 weeks. Thereafter, the rats were anaesthetised, perfused and the spinal cords were prepared for microscopic investigation. A morphologic method, using light and electron microscopic examination of the cross‐section of the spinal cord, was combined with a quantitative morphometric analysis of the number and size of neuronal cells in the dorsal horn as a sensitive indicator of neurotoxicity. Using the laser‐Doppler flowmetry technique, the effects of saline and sameridine (1, 5 and 10 mg/ml) on spinal cord blood flow (SCBF) was studied.Results: No signs of neurotoxicity could be seen in any of the animals and no significant differences were seen when comparing the cell number or cell sizes in the groups injected with sameridine, bupivacaine or saline. After IT administration of 10 mg/ml sameridine a significant, short‐lasting, decrease in SCBF (72% of pre‐drug value) was seen.Conclusion: In conclusion, our studies do not show any signs of neurotoxic effects of IT administration of sameridine in the rat. A transient decrease in SCBF was noted after IT injection of sameridine 10 mg/ml.
Effects of amide local anaesthetics on eicosanoid formation in burned skin
Authors: Jönsson A. , Cassuto J. , Tarnow P. , Sinclair R. , Bennett A. , Tavares I. A. 
Published: March 2003

Bacground: Previous studies have demonstrated potent inhibition of burn oedema and progressive ischaemia by local anaesthetics. Since eicosanoids have been suggested to play an important role in the pathophysiology of burns, we compared in the present ex vivo study the effects of topical lidocaine/prilocaine cream (EMLA®, ASTRA, Sweden) and intravenous lidocaine with that of saline on eicosanoid formation by normal and burned rat skin.Methods: A full‐thickness burn trauma was induced in the abdominal skin. All the agents were given 5 min postburn until 2 h after the trauma. The experimental skin was subsequently removed and incubated in Krebs solution for 1 h. Eicosanoid concentrations in the solution were analysed by radioimmunoassay.Results: EMLA® cream induced a significant inhibition of TXB2 (P<0.05) and 6‐Keto‐PGF1α (P<0.01) but not of PGE release from burned skin as compared to saline treatment. Intravenous lidocaine infusions did not significantly influence the release of any of the measured eicosanoids versus saline.Conclusion: In conclusion, the lack of effect of intravenous lidocaine could relate to the severe burn trauma inducing rapid ischaemia which may have interfered with the delivery of the agent to the burned tissues or to insufficient concentrations achieved in the burn area. Topical treatment of burned skin with a local anaesthetic cream significantly reduced the release of TXB2 and 6‐Keto‐PGF1α, suggesting a possible mechanism of action in progressive burn ischaemia.
Systemic levels and preportal organ release of tissue‐type plasminogen activator are enhanced by PEEP in the pig
Authors: Seeman‐Lodding H. , Häggmark S. , Jern C. , Jern S. , Johansson G. , Winsö O. , Biber B. 
Published: March 2003

Background: Endothelium‐derived tissue‐type plasminogen activator, t‐PA, is the key enzyme in the initiation of endogenous thrombolysis. Plasma levels of t‐PA increase in response to sympatho‐adrenergic activation. In the mesenteric vascular bed an increased norepinephrine spillover has been observed during positive end‐expiratory pressure ventilation, PEEP. This experimental study examines the effects of PEEP‐induced alterations on regional release rates and systemic levels of t‐PA in vivo.Methods: The protocol included measurements of arterio‐venous concentration gradients of t‐PA and the respective plasma flow across the pulmonary, coronary, hepatic and preportal vascular beds, in pigs, during zero‐PEEP and at 2, 4 and 10 min after the application of a PEEP of 10 cm H2O. Both total plasma t‐PA antigen (ELISA with a porcine t‐PA standard) and active t‐PA (spectrophotometric functional assay) were determined.Results: During zero‐PEEP, a high preportal basal net release and hepatic net uptake of total t‐PA was observed. With PEEP, the magnitude of the preportal net release of t‐PA was markedly enhanced (+24±5%), as was hepatic net uptake (+21±8%), simultaneously to a significant decrease in liver plasma flow (−30±2%). PEEP‐induced alterations in active t‐PA mirrored those observed in total t‐PA. No significant net fluxes of total or active t‐PA were observed across the coronary or the pulmonary vascular beds.Conclusions: Clinically used levels of PEEP induce increases in net release of endothelially derived t‐PA within preportal organs. The application of PEEP is associated with increased systemic levels of total and active t‐PA, in spite of a simultaneous increase in hepatic net uptake, indicating that the preportal vascular bed can not account for the systemic t‐PA response.
Tropisetron or droperidol in the prevention of postoperative nausea and vomiting
Authors: Jokela R. , Koivuranta M. 
Published: March 2003

Background: Women undergoing laparoscopic cholecystectomy are susceptible to postoperative nausea and vomiting (PONV). This study was undertaken to evaluate the efficacy of tropisetron or droperidol for preventing PONV after laparoscopic cholecystectomy.Methods: In a prospective, randomised, double‐blind trial, 120 female patients received either tropisetron 5 mg or droperidol 1.25 mg intravenously at the beginning of surgery. A standard general anaesthetic technique and postoperative analgesia were used. Nausea, emetic episodes and the need for rescue medication were recorded for 24 h postoperatively.Results: Nausea was experienced by 55% of the patients in the tropisetron group and by 62% in the droperidol group (ns). The incidence of emetic episodes was 20% and 52% (P=0.001) in the two groups, respectively. Rescue antiemetic medication was needed in 42% and 50% (ns) of the patients, respectively. Patients in the droperidol group were more drowsy in comparison with patients in the tropisetron group, mean sedation score being 6.7 vs 5.7, respectively (P=0.023). No difference in other side‐effects was observed.Conclusion: Tropisetron, when compared with droperidol, had no better efficacy on the prevention of postoperative nausea but resulted in a significantly lower incidence of vomiting after laparoscopic cholecystectomy.
Pollution with nitrous oxide using laryngeal mask or face mask
Authors: Jenstrup M. , Fruergaard K. O. , Mortensen C. R. 
Published: March 2003

Background: As environmental pollution by nitrous oxide may influence the health of the personnel working in operating theatres, the incidence and magnitude of nitrous oxide (N2O) leakage, when using a face mask or a laryngeal mask airway (LMA) for controlled ventilation, were studied in 34 patients scheduled for elective cystoscopy.Methods: A semi‐closed gas delivery ventilation system with active scavenging was used. The N2O concentrations were measured every 8 s at a position 30 cm above the patient's mouth with a N2O gas monitor (GD 200, Simrad Optronics).Results: When using a face mask, the leakage of N2O resulted in a N2O concentration of 157 (85–332) p.p.m. (parts per million) (median concentration and 25% and 75% percentiles). With the LMA, a lower median concentration of N2O of 60 (28–126) p.p.m. was found (P=0.04). With the face mask, a concentration above 100 p.p.m. was found during 51% of the exposure time compared to 24% of the time in the LMA group.Conclusion: Environmental pollution was less with the LMA than the face mask, but under the conditions of the study both modes of airway management were associated with levels of N2O peak concentrations in the breathing zone of anaesthetists that are deemed to be excessively high by the Danish National Institute for Occupational Safety.
Clinical experience using intrathecal (IT) bupivacaine infusion in three patients with complex regional pain syndrome type I (CRPS‐I)
Authors: Lundborg C. , Dahm P. , Nitescu P. , Appelgren L. , Curelaru I. 
Published: March 2003

Background and aim: To date, there is no reliable method for treating the severe pain and for modifying the natural evolution of CRPS‐I. Therefore, we explored the effect of long‐term IT bupivacaine infusion (with or without buprenorphine) on this syndrome.Patients and methods: (a) Patients: two women and one man, 25, 31 and 42 years old, with CRPS‐I of the lower (n=2) or upper (n=1) extremity lasting for 4 and 5 months, and 14 years. (b) Interventions: insertion of externalized IT catheters; IT infusion of buprenorphine 0.015 mg/ml and bupivacaine 4.75 mg/ml (n=1), or only bupivacaine 5 mg/ml (n=2) from external electronic pumps.Results: The IT treatment lasted for 172, 282 and 668 days. The mean/maximal daily doses of the IT bupivacaine were 39/66, 55/80 and 69/125 mg, respectively. The pain intensity decreased from VASmean=7±1 to VASmean=2±2. None of the patients had regression of allodynia, edema, and trophic disturbances in the affected extremities. In 2 patients, the IT treatment did not prevent spread of the disease to the opposite extremity or the occurrence of phantom pain and stump allodynia after amputation. The IT catheters were withdrawn as being no longer needed: in 2 patients 56 and 458 days after amputation of the involved extremity, and in another one before replacement of the IT bupivacaine infusion with epidural dorsal column stimulation (EDCS). After termination of the IT treatment, the patients were observed for 1437, 1575, and 2689 days (until September 1, 1998). At that date, all the patients were alive, and still affected by their CRPS‐I, either in the amputation stump (n=2), and/or in the opposite or remote extremities (n=2); further, two were unemployed and one worked for 75% of the time. One of them was taking up to 1500 mg of slow‐release morphine to cope with pain.Conclusion: The IT pain treatment with bupivacaine (with or without buprenorphine) alleviated the “refractory” pain, but affected neither the associated symptoms and signs of the CRPS‐I, nor its natural evolution. Thus, the IT treatment cannot be recommended in preference to other pain treatment regimens for CRPS‐I.
Perioperative gastric tonometric PCO2 and intramucosal pH in patients undergoing liver transplantation
Authors: Rønholm E. , Runeborg J. , Karlsen K. L. , Tomasdottir H. , Åneman A. , Bengtsson A. 
Published: March 2003

Background: Extensive research has focused on the role of insufficient gastro‐intestinal perfusion and inflammatory activation in the development of organ dysfunction during critical illness. In patients undergoing liver transplantation, portal and caval vein clamping leads to gastro‐intestinal and lower extremity venous congestion during the anhepatic phase, and studies suggest that gastro‐intestinal perfusion may be compromised. This study was performed to investigate gastro‐intestinal perfusion in patients undergoing liver transplantation.Methods: In 16 patients undergoing liver transplantation, perioperative gastric tonometry with determination of tonometric PCO2, tonometric‐arterial PCO2 gradient and intramucosal pH were performed. Blood gases were obtained simultaneously from the arterial and portal vein blood.Results: Tonometric PCO2 was 4.6 (4.2/5.3) kPa preoperatively and increased to 5.6 (4.5/6.0) kPa during the anhepatic phase (P<0.01), while the tonometric‐arterial PCO2 gradient increased from −0.3 (−0.5/0.0) kPa preoperatively to 0.7 (0.3/1.2) kPa during the anhepatic phase (P<0.01). Intramucosal pH decreased to 7.27 (7.21/7.32) u during the anhepatic phase (P<0.01, compared to preoperatively). The portal vein PCO2 was not significantly different from arterial PCO2 or tonometric PCO2 at any measurement point.Conclusion: This study demonstrates that clinical liver transplantation is associated with gastro‐intestinal perfusion in the range of aerobic metabolism. The results do not support the presence of gastro‐intestinal perfusion in the range of anaerobic metabolism.
Intraperitoneal and sigmoid colon tonometry in porcine hypoperfusion and endotoxin shock models
Authors: Koga I. , Stiernström H. , Christiansson L. , Wiklund L. 
Published: March 2003

Background: The objective of the present study was to assess the accuracy of an air tonometry device in vivo within a wide range of regional carbon dioxide tension (PrCO2) values by using saline tonometry as the standard and to investigate the possibilities to monitor perfusion of the intestine by tonometry in the intraperitoneal cavity.Methods: Piglets were anesthetized and mechanically ventilated. A pair of tonometry catheters was placed in the sigmoid colon, while another pair was placed intraperitoneally in the right lower quadrant of the abdomen. Air tonometric regional PCO2 (aPrCO2) was measured every 15 min intraperitoneally and every 20 min in the sigmoid colon. Saline tonometric measurements were made every 30 min and steady‐state values (ssPrCO2) were derived. Hypoperfusion shock was induced by graded constriction of the aorta. Endotoxin shock was induced by administration of lipopolysaccharide (LPS).Results: The obtained average PrCO2 (=matched (aPrCO2+ssPrCO2)/2) values ranged from 5.1 kPa to 14.7 kPa. Regional air PCO2 (aPrCO2) and steady‐state saline PCO2 (ssPrCO2) exhibited a strong positive linear relationship (r=0.959). The 95% confidence interval of the mean of dPrCO2 (=aPrCO2−ssPrCO2) was 0.31–0.46 kPa. Intraperitoneal tonometric PrCO2 was lower than intraluminal PrCO2 in the sigmoid colon, and was also more sensitive to circulatory changes than sigmoid colon PrCO2.Conclusion: The regional air PCO2 (aPrCO2) showed good agreement with the steady‐state saline regional PCO2 (ssPrCO2). Intraperitoneal measurements may be an alternative method of monitoring intestinal perfusion after abdominal surgery.
Dopamine reduces gastric tone in a dose‐related manner
Authors: Levein N. G. , Thörn S. E. , Lindberg G. , Wattwil M. 
Published: March 2003

Background: Dopamine may have effects on gastrointestinal motility. The aim of this study was, therefore, to determine whether dopamine reduces gastric tone and whether the effects of dopamine can be blocked by a dopamine antagonist.Methods: Eight healthy male volunteers were studied on two occasions in a randomized order. A continuous infusion of incremental doses of dopamine (2.5, 5.0, 7.5 μg kg−1 min−1) was given on both occasions. Ten milligrams of the dopamine‐antagonist metoclopramid was given before the dopamine infusion on one occasion and during the dopamine infusion (7.5 μg kg−1 min−1) on the other occasion. The gastric tone was measured by an electronic barostat, an instrument with an electronic control system that maintains a constant preset pressure within an airfilled, flaccid intragastric bag by means of momentary changes in the intragastric volume of air. Volume and pressure in the gastric bag were continuously recorded by the electronic barostat and sampled in a computer.Results: Dopamine induced a dose‐related increase in the intragastric bag volume. Metoclopramid given as a 10 mg i.v. bolus dose during the infusion of dopamine significantly decreased the intragastric bag volume, but 10 mg of metoclopramid i.v. before the dopamine infusion did not influence the bag volume per se.Conclusion: Dopamine decreases gastric tone in a dose‐related manner and 10 mg of the dopamine‐antagonist metoclopramid is not enough to fully reverse these effects.
Perioperative transcutaneous pacemaker in patients with chronic bifascicular block or left bundle branch block and additional first‐degree atrioventricular block
Authors: Gauss A. , Hübner C. , Meierhenrich R. , Röhm H.‐J. , Georgieff M. , Schütz W. 
Published: March 2003

Background: Complete heart block is dreaded perioperatively in patients with chronic bifascicular or left bundle branch block (LBBB) and additional first‐degree A‐V block. Our aim was to investigate the necessity as well as the efficacy and safety of transcutaneous pacing in the perioperative setting.Methods: Thirty‐nine consecutive patients with asymptomatic chronic bifascicular block or LBBB and prolongation of the P‐R interval scheduled to undergo surgery under anesthesia were prospectively enrolled in the study. Preoperatively, a transcutaneous pacemaker (PACE 500 D, Osypka Co.) was applied; its efficacy was checked with intra‐arterial blood pressure measurement; the pain level was recorded. Additionally, 24‐h Holter monitoring (CM2, CM5) was applied. Occurrences of a block progression or a bradycardia of <40 beats/min with hemodynamic impairment were the defined end points.Results: Thirty‐seven of the 39 patients (95%) could be successfully stimulated with a median current strength of 70 mA; whereby 33 of the 39 patients felt moderate to severe pain. There was no perioperative block progression. Three cases of bradycardia of <40 beats/min with a critical drop in blood pressure occurred; but these patients were successfully treated with drug therapy without pacemaker stimulation.Conclusion: The perioperative application and testing of the pacemaker was safe and could be performed in nearly all patients successfully. However, we do not consider a routine prophylactic transcutaneous placement in patients with chronic bifascicular or LBBB and additional first‐degree A‐V block justified. Nevertheless, appropriate drugs and temporary pacemaker equipment should be easily accessible.
Ketamine antagonises alfentanil‐induced hypoventilation in healthy male volunteers
Authors: Persson J. , Scheinin H. , Hellström G. , Björkman S. , Götharson E. , Gustafsson L. L. 
Published: March 2003

Background: The effects of ketamine on respiration, alone, or in combination with opioids, have not been completely clarified. Both stimulant and depressant effects have been reported, as well as attenuation of opioid‐induced hypoventilation at the expense of increased oxygen consumption. These conflicting results might partly be due to dose‐dependent mechanisms. We have, therefore, determined the ventilatory effects of ketamine, in combination with alfentanil, using infusions to different pseudo steady‐state concentrations.Methods: On two separate days, eight healthy male volunteers were given alfentanil as a continuous computer‐controlled infusion, aiming at a plasma concentration of 50 ng  ·  mL−1. After reaching apparent steady‐state for alfentanil, racemic ketamine or placebo was administered in a protocol randomised for the two days. On the ketamine days a computer‐controlled infusion, aiming for escalating ketamine plasma concentrations of 50, 100 and 200 ng  ·  mL−1, was added to the alfentanil infusion. On the placebo days saline was added. Using a face‐mask with an occlusion valve, respiratory parameters were measured during air‐breathing and after 6 repetitive 30‐s CO2 challenges.Results: The alfentanil infusion induced hypoventilation by decreasing respiratory rate, while tidal volume and respiratory drive were unaffected. This hypoventilation was antagonised by ketamine in a concentration‐dependent manner mainly through an increase in respiratory rate. The CO2 response was not affected by alfentanil or ketamine.Conclusion: In the dose range of interest for postoperative, intensive‐care and pain‐clinic settings, ketamine antagonises the resting hypoventilation induced by alfentanil.
Axillary brachial plexus block with ropivacaine 7.5 mg/ml
Authors: Ræder J. C. , Drøsdahl S. , Klaastad Ø. , Kvalsvik O. , Isaksen B. , Strømskag K. E. , Mowinckel P. , Bergheim R. , Selander D. 
Published: March 2003

Background: Ropivacaine is less cardiotoxic than bupivacaine and may be used in higher doses in order to increase the quality of a block. The aim of this study was to compare the efficacy and safety of 40 ml ropivacaine 7.5 mg/ml (300 mg) and 40 ml bupivacaine 5 mg/ml (200 mg) for axillary plexus block.Methods: One hundred and four adult patients were included in a prospective , double‐blind study. Sensory and motor block were tested for the five main terminal nerves of the arm at 10‐min intervals until start of surgery and every second hour thereafter until full resolution of the block.Results: The overall evaluation of the block by the surgeon and the anesthesiologist showed a significantly better quality in the ropivacaine patients, regarding both anesthesia and motor block. There were no differences in the time to onset and duration of the block. Except for one patient, who had seizures after an accidental IV injection of ropivacaine, there were no major side effects.Conclusion: Ropivacaine 7.5 mg/ml, 40 ml, produces axillary plexus block of similar onset and duration but better quality than 40 ml of bupivacaine 5.0 mg/ml.