bluuebunny/crossref_metadata_2025 huggingface dataset:
Cardiopulmonary bypass elicits a pro‐ and anti‐inflammatory cytokine response and impaired neutrophil chemotaxis in neonatal pigs
Authors: Brix‐Christensen V. , Petersen T. K. , Ravn H. B. , Hjortdal V. E. , Andersen N. T. , Tønnesen E.
Published: March 2003

Background: Cardiopulmonary bypass (CPB) induces a systemic inflammatory response and organ dysfunction, especially in children. Plasma concentration of inflammatory markers are increased in response to the trauma of cardiac surgery and CPB. The aim of the present study was to investigate whether the CPB procedure in itself elicits increased levels of inflammatory markers in neonatal pigs.

Methods: The inflammatory response was measured in piglets undergoing sternotomy alone (sham group, n=13) or sternotomy and CPB (n=14). Inflammatory mediators were measured at baseline and at fixed time‐points during and after CPB. IL‐8, IL‐10 and TNF‐α levels and C‐reactive protein (CRP) concentrations were measured in plasma samples. Polymorphonuclear neutrophils (PMN) chemotaxis was measured ex vivo, and CD‐18 expression using an immunofluorescence technique.

Results: Immediately after the CPB procedure increased IL‐8 levels were found in the CPB group, but not in sham operated animals (P=0.005). Simultaneously, a marked IL‐10 response was measured in the CPB group. Concurrently, PMN chemotaxis decreased in CPB animals but not in the sham group (P=0.04). CD‐18 expression and CRP levels were not significantly different between groups and TNF‐α showed no changes in either group. The chemotactic response did not correlate with plasma IL‐8 or IL‐10, nor with CD‐18 expression.

Conclusion: The CPB procedure elicited a systemic inflammatory response in terms of significantly elevated plasma levels of IL‐8 and IL‐10. Furthermore, a temporary and simultaneous decrease in PMN chemotaxis was observed immediately after CPB.
Changes in circulating blood volume after infusion of hydroxyethyl starch 6% in critically ill patients
Authors: Christensen P. , Andersson J. , Rasmussen S. E. , Andersen P. K. , Henneberg S. W.
Published: March 2003

Background: The cardiovascular response to a volume challenge with hydroxyethyl starch (HES) (200/0.5) 6% depends on the relation between the volume of HES 6% infused and the expansion of the blood volume in critically ill patients. However, only relatively limited data exist on the plasma expanding effect of infusion of HES 6% in critically ill patients. The purpose of the study was to evaluate the variation in the expansion of the circulating blood volume (CBV) in critically ill patients after infusion of 500 ml of colloid (HES (200/0.5) 6%) using the carbon monoxide method.

Methods: In 20 consecutive patients admitted to the ICU requiring mechanical ventilation and volume expansion, 500 ml of HES (200/0.5) 6% was infused. The CBV was measured immediately before the infusion, 10 min after completing the infusion and then hourly for 8 h.

Results: The median volume expansion immediately after infusion was 470 ml (range 270 ml to 840 ml). The corresponding values after 4 h and 8 h were 265 ml (range −30 ml to 460 ml) and 120 ml (range −210 ml to 360 ml), respectively. The increase in CBV was only statistically significant for 4 h. The coefficient of variation of the method for estimation of CBV was 3.6%.

Conclusions: The large interindividual variation of the volume expansion after infusion of HES 6% in critically ill patients illustrates one of the difficulties in optimizing colloid therapy and interpretating the changes in hemodynamic variables after a colloid challenge.
Effects of dopamine on porcine myocardial action potentials and contractions at 37 °C and 32 °C
Authors: Roscher R. , Arlock P. , Sjöberg T. , Steen S.
Published: March 2003

Background: Little information exists on the effects of drugs with cardiovascular action in hypothermia, and some findings have indicated paradoxic effects of dopamine in this setting. As we have not found any data on the electrophysiologic and contractile effects of dopamine on the heart in hypothermia, we decided to study this in pig myocardium, since pigs have a cardiovascular system more similar to that of humans than other animals.

Methods: Excised muscle strips from pig ventricular septum were mounted in an organ bath. After 45 min of equilibration at 37 °C or 32 °C, resting and action potentials, time to peak contraction and contractile force were recorded during pacing with a frequency of 60/min. Dopamine at 4 μM or 8 μM was added and new recordings were made after 15 min.

Results: Cooling to 32 °C caused a prolongation of contraction by 48% and the contractile force increased by 39%. The membrane action potential duration at 50% and 90% repolarization levels increased at 32 °C by 28% and 16% respectively. Dopamine significantly (P<0.05) increased the contractile force and membrane action potential duration at 50% and 90% repolarization levels both in normothermia and in hypothermia, whereas the duration of the contraction was not significantly changed.

Conclusion: Cooling to 32 °C significantly prolongs the myocardial action potential and the contraction duration. Dopamine increases the contractile force and prolongs the action potential both at 37 °C and at 32 °C.
Spasmolytic effect of magnesium sulfate on serotonin‐induced pulmonary hypertension and bronchoconstriction in dogs
Authors: Yoshioka H. , Hirota K. , Sato T. , Hashimoto Y. , Ishihara H. , Matsuki A.
Published: March 2003

Background: Magnesium (Mg2+) has relaxant effects on histamine‐induced bronchoconstriction. In addition, Mg2+ has been reported to reduce vascular smooth muscle tone and be clinically useful for treatment of persistent pulmonary hypertension of the newborn. In this study, we evaluated the relaxant effect of Mg2+ on serotonin (5HT)‐induced bronchoconstriction and pulmonary hypertension.

Methods: Seven mongrel dogs were anesthetized with pentobarbital (30 mg · kg−1+2 mg · kg−1 · h−1) and paralyzed by pancuronium (0.2 mg · kg−1 · h−1). Bronchoconstriction and pulmonary hypertension were elicited with 5HT (10 μg · kg−1+1 mg · kg−1 · h−1). Airway caliber was evaluated by changes in bronchial cross‐sectional area (BCA) of the 3rd bronchial bifurcation measured by a fiberoptic bronchoscope method as previously reported. Pulmonary hypertension was assessed by changes in pulmonary vascular resistance (PVR). The BCA and PVR were expressed as per cent of the basal level. Thirty minutes after start of 5HT infusion, magnesium sulfate (MgSO4): 0 (saline), 1, 10, 100 and 1000 μmol · kg−1 was given iv. Arterial blood was also collected to measure plasma level of Mg2+ and catecholamines.

Results: 5HT increased %PVR to 163±25% and decreased % BCA by 39.2±4.5%. Plasma level of Mg2+ following MgSO4 1000 μmol · kg−1 iv exceeded its toxic level. The ED50s of MgSO4 (dose producing 50% relaxation of maximal constriction) was 47.8 μmol · kg−1 and 1.09 mmol · kg−1 for pulmonary hypertension and bronchoconstriction, respectively. The ratio of %PVR to %SVR was about 1.0 after MgSO4 0–100 μmol · kg−1 iv, although the ratio significantly increased after 1000 μmol · kg−1 iv.

Conclusion: In dogs, 5HT‐induced pulmonary hypertension but not bronchoconstriction was significantly reduced by an iv bolus of MgSO4, resulting in a plasma concentration within the assumed therapeutic level.
No effect of L‐arginine supplementation on pulmonary endothelial dysfunction after cardiopulmonary bypass
Authors: Angdin M. , Settergren G. , Liska J. , Astudillo R.
Published: March 2003

Background: Acetylcholine is an endothelium‐dependent vasodilator through the L‐arginine‐nitric oxide pathway. After ischemia‐reperfusion this effect is attenuated, also demonstrated in the pulmonary circulation after cardiopulmonary bypass. Administration of L‐arginine has been shown to have a protective effect on endothelial function in reperfusion injury. The aim of the current study was to test the possible effect of L‐arginine on the acetylcholine reactivity in the pulmonary circulation after cardiopulmonary bypass.

Methods: Thirty‐five patients with ischemic and/or valvular heart disease were investigated in a randomized, double‐blinded, placebo‐controlled study. The patients were divided into three groups. Group 1: high dose L‐arginine (n=10), group 2: low dose L‐arginine (n=10), group 3: placebo, no L‐arginine, (n=15). The acetylcholine reactivity was tested with measurements of pulmonary vascular resistance before surgery and 1, 2 and 3–4 h after cardiopulmonary bypass.

Results: After cardiopulmonary bypass an attenuation of the acetylcholine reactivity over time was observed in all groups, with no differences between groups.

Conclusion: In the current study L‐arginine had no protective effect on the pulmonary endothelium after cardiopulmonary bypass, measured as reactivity to an infusion of acetylcholine.
Etomidate and thiopental inhibit platelet function in patients undergoing infrainguinal vascular surgery
Authors: Gries A. , Weis S. , Herr A. , Graf B. M. , Seelos R. , Martin E. , Böhrer H.
Published: March 2003

Background: Postoperative platelet hyperaggregability following general anesthesia has been reported in patients undergoing major vascular surgery. In contrast, since anesthetic agents inhibited platelet function both in vitro and in vivo, an increased risk for postoperative bleedings due to prolonged platelet dysfunction has been discussed. Nevertheless, data describing platelet‐affecting properties of induction agents such as etomidate and thiopental in patients undergoing major vascular surgery are lacking.

Methods: Platelet function was determined at 0, 2, 20, and 200 μg/ml thiopental and at 0, 0.2, 2, 20 μg/ml etomidate in vitro in blood samples drawn from 16 patients suffering from severe occlusive arterial disease. In addition, 30 patients undergoing vascular surgery were investigated before (PRE) and after anesthesia induction (T0) either with etomidate (ETO group, n=16) or thiopental (THIO group, n=14), and 2 h after the beginning of surgery (T2). Platelet function was determined according to platelet aggregation, in vitro bleeding time, and flow cytometric measurements.

Results: In vitro, P‐selectin expression was inhibited by etomidate at 2 and 20 μg/ml (−28% and −38%, respectively) and also by thiopental at 200 μg/ml (−27%). In patients undergoing vascular surgery, anesthesia induction in the ETO group resulted in a 31% prolongation of the in vitro bleeding time and an inhibition of ADP‐ and collagen‐induced platelet aggregation (−30% and −17%, respectively) and of P‐selectin expression (−25%) at T0. In the THIO group, only ADP‐induced platelet aggregation was affected (−16%). At T2, all parameters had reached PRE level again in both groups. Furthermore, in comparison with the THIO group, operation time was significantly prolonged and transfusion volume was significantly increased in the ETO group. In addition, platelet count and hematocrit significantly decreased at T2, whereas levels of tPA, PAI‐1, fibrinogen and antithrombin III and partial thromboplastin time remained unchanged in both groups during the study period.

Conclusions: In the present study, etomidate and, to a minor extent, thiopental offered significant platelet inhibitory properties. Anesthetic‐induced platelet inhibition may lead to higher transfusion rates and prolonged operation times. Therefore, anesthetic‐related platelet inhibitory properties should be considered when searching for the anesthetic agent of choice, especially in patients with compromised hemostasis and co‐existing bleeding disorders.
Retracted: Price development in important anesthesia and critical care medicine journals in comparison to journals of other disciplines
Authors: Boldt J. , Maleck W. H. , Fent T.
Published: March 2003

Background: In today’s climate of financial restrictions, libraries and individual subscribers complain about the price increase of scientific journals. The development in prices of anesthesia/critical care journals was analysed over the past 6 years and compared to prices of some journals of other disciplines.

Methods: Important journals in the categories Anesthesiology, Emergency Medicine & Critical Care, Surgery, Medicine (General), and Cardiac & Cardiovascular Systems listed in the 1999 Science Citation Index of Journal Citation Report were included and prices for the years 1995 to 2000 were analysed.

Results: Increase in prices ranged from +13% to +199%. The mean increase in journal prices was lowest in the category Anesthesiology (+61%), higher in the category Critical Care (+73%), and highest in the category Medicine, General (+101%). Changes in the impact factor (IF) varied widely, ranging from a decrease (Lancet: −43%; J Neurosurg Anesth: −44%) to a tremendous increase (e.g. Reg Anesth +165%; Ann Emerg Med +149%). The journals’ size (number of articles or pages) did not increase proportionally with the increase in prices.

Conclusion: A disproportionate rise in journal prices was seen over the past 6 years. The large increase in cost may have multiple reasons. The rapidly increasing cost of research journals may affect research quality because economic pressure may result in reduction in availibility of information due to cancellation of subscriptions to journals.
Patient‐controlled epidural analgesia versus continuous epidural analgesia after total knee arthroplasty
Authors: Silvasti M. , Pitkänen M.
Published: March 2003

Background: Patient‐controlled epidural analgesia (PCEA) has been found to be an effective method for pain relief during labour and after surgery. The goal of this study was to compare the efficacy of bupivacaine–fentanyl PCEA and continuous epidural infusion with the same mixture for treatment of pain after total knee arthroplasty.

Methods: Fifty‐four patients under spinal anaesthesia were allocated to two groups in this randomized, double‐blind study: the PCEA group could demand a bolus of 0.05 ml/kg of the bupivacaine 1.1 mg/ml and fentanyl 5 μg/ml solution, with a lockout interval of 10 min and total dose limit of three bolus doses per hour. The EPI group received a continuous infusion of 0.1 ml kg−1 h−1 of the same bupivacaine–fentanyl solution, and only a minimal extra bolus dose of 0.2 ml with the same lockout interval. All the patients received also paracetamol 1 g, orally, three times a day. In addition to pain scores at rest and during leg lifting, the 20‐h analgesic consumption and the incidence of side effects were recorded.

Results: Forty‐nine patients completed the study. The bupivacaine and fentanyl consumption during 20 h was smaller in the PCEA group (P<0.001). Analgesia and the need for rescue‐opioid medication were similar in both groups. There were no differences between the PCEA and EPI groups regarding the incidence of side effects. Five patients were confused about how to operate the PCEA apparatus.

Conclusion: The amount of bupivacaine–fentanyl solution consumed was significantly less with PCEA than with continuous infusion of bupivacaine–fentanyl solution without affecting the quality of postoperative analgesia after total knee arthroplasty. Several of the elderly patients had difficulties in operating the PCEA apparatus.
Ropivacaine 1 mg  ·  ml−1 does not decrease the need for epidural fentanyl after hip replacement surgery
Authors: Kostamovaara P. A. , Laurila J. J. , Alahuhta S. , Salomäki T. E.
Published: March 2003

Background: Ropivacaine is a new long‐acting local anesthetic. Laboratory trials have demonstrated a synergistic analgesic effect between intrathecal opioids and local anesthetics. We tested the hypothesis that addition of ropivacaine 1 mg  ·  ml−1 to epidural fentanyl (10 μg  ·  ml−1) postoperatively decreases the need for fentanyl, improves the quality of analgesia and decreases the side‐effects of fentanyl.

Methods: Forty patients were enrolled in this double‐blind, randomized study to receive either fentanyl 10 μg  ·  ml−1 (group F) alone or fentanyl combined with ropivacaine 1 mg  ·  ml−1 (group R) for 20 h as an epidural infusion at TH12–L1 or L1–L2 for analgesia after hip replacement surgery. The patients were free to use a patient‐controlled epidural analgesia device, which was programmed to infuse 3 ml of the study medication hourly and to allow a 3‐ml bolus when needed (maximal hourly dose of fentanyl was 150 μg). The consumption of medication, visual pain scores at rest and on movement, hemodynamic and respiratory parameters, motor and sensory block, nausea, pruritus and sedation were recorded.

Results: There were no significant differences between the groups in the total mean fentanyl consumption (1.10±0.18 mg in group F, 1.08±0.31 mg in group R, 95% CI: −0.14 to 0.19, P=0.774). The pain scores were similar at rest (median scores ≤1) and on movement (median scores ≤3). The adverse effects were similar and of a minor nature, consisting mostly of pruritus and nausea.

Conclusion: Addition of ropivacaine 1 mg  ·  ml−1 to epidural fentanyl 10 μg  ·  ml−1 did not significantly decrease the requirement for fentanyl administered for pain relief after hip replacement surgery.
A small dose of droperidol decreases postoperative nausea and vomiting in adults but cannot improve an already excellent patient satisfaction
Authors: Hechler A. , Neumann S. , Jehmlich M. , Lange U. , Hopf H.‐B.
Published: March 2003

Background: We evaluated whether or not 1) a routine prophylaxis with 20 μg  ·  kg−1 body weight of droperidol would efficiently prevent postoperative nausea and vomiting (PONV) after elective surgery in adults and 2) an efficient prophylaxis would improve patient satisfaction.

Methods: With approval of the local ethics committe and after having obtained informed written consent, 1334 patients in a randomised, single‐blinded fashion either received droperidol (group 1, n=665) or saline intravenously (group 2, n=669) 20 min before the end of a standard O2/N2O/fentanyl/isoflurane anaesthesia of at least 30 min duration. End points: incidence of PONV during the first 24 h; individual episodes of nausea or vomiting, overall patient satisfaction with the procedure.

Results: Compared to saline, intravenous injection of droperidol substantially and significantly reduced the incidence of PONV from 30% to 20% (P<0.0001). Women suffered three times more frequently from PONV (10.5% vs. 30%, P<0.0001). Droperidol significantly reduced the incidence of PONV from 35.4% to 24.4% in women (relative risk reduction: 31%, P=0.0002), but not in men (13.1% vs. 8.2%, relative risk reduction: 37%, P=0.159) – without impact on overall patient satisfaction (98.8% vs. 97.1%, P=0.439). Distribution of surgical procedures, sex, age, height, weight and anaesthetic duration were not different between groups. To prevent one woman from suffering PONV, nine had to be treated prophylactically at an individual drug cost (German prices) of about  0.80 per woman.

Conclusion: Routine PONV prophylaxis with 20 μg  ·  kg−1 body weight of droperidol is cost‐efficient and appropriate in women but not in men.
Use of olprinone, a phosphodiesterase III inhibitor, in an asthmatic patient
Authors: Hirota K. , Kabara S. , Hashimoto H. , Ishihara H. , Matsuki A.
Published: March 2003

Phosphodiesterase (PDE) III exists in airway smooth muscles. In addition, PDEIII inhibitors have been suggested to relax airway smooth muscle by increasing intracellular cAMP concentrations. We report a successful use of olprinone, a PDEIII inhibitor, for treatment of an asthmatic attack. A 15‐year‐old male patient treated with oral theophylline 400 mg· d−1 was anesthetized with propofol, fentanyl and ketamine for knee joint surgery. Immediately after tracheal intubation, an asthma attack occurred with peak airway pressure (Paw)>40 cmH2O. Thus, propofol 20 mg was additionally given to increase anesthetic depth, and Paw gradually decreased to 30 cmH2O. In addition, we started monitoring bronchial cross‐sectional area using a superfine fiberoptic bronchoscopic method previously reported. However, as Paw did not further decrease for 30 min, olprinone was intravenously infused (10 μg · kg−1 · 10 min−1+0.3 μg · kg−1 · min−1, total 5 mg). Olprinone infusion rapidly decreased peak Paw from 30 cmH2O to 24 cmH2O and increased bronchial cross‐sectional area by 50%. These findings suggest that olprinone produced bronchodilation.
Long‐term infusion of atrial natriuretic peptide (ANP) improves renal blood flow and glomerular filtration rate in clinical acute renal failure
Authors: Swärd K. , Valson F. , Ricksten S.‐E.
Published: March 2003

Background: Short‐term infusion of atrial natriuretic peptide (ANP) increases renal blood flow (RBF) and glomerular filtration rate (GFR) in patients with acute renal dysfunction. In the present study we evaluated the effects of long‐term infusion (>48 h) of ANP on (RBF) and (GFR) in 11 postcardiac surgical patients requiring pharmacological circulatory support and with acute renal impairment.

Methods: Urinary clearance of Cr‐EDTA and PAH as well as central hemodynamic measurements were performed for 2–3 consecutive 30‐min periods during ANP infusion (50 ng · kg−1 · min−1), one hour after abrupt discontinuation of ANP and again immediately after reinstitution of ANP infusion.

Results: During ANP infusion, urine flow (UF), GFR, RBF and renal vascular resistance (RVR) were 6.4±1.1 ml · min−1, 19.9±3.1 ml · min−1, 408±108 ml · min−1 and 0.286±0.054 mmHg · min · ml−1, respectively. UF, GFR and RBF decreased significantly by 28% (P<0.001), 32% (P<0.01) and 31% (P<0.05), respectively when ANP infusion was discontinued. RVR increased by 93% (P<0.05) while there was no change in filtration fraction. After reinstitution of ANP infusion, all measured renal variables returned to baseline. There was no significant correlation between the number of ANP treatment days and the percentage decrease in GFR (r=0.18) or RBF (r=0.22) during ANP withdrawal. Central hemodynamic variables were not affected by ANP withdrawal.

Conclusions: ANP infusion improves RBF and GFR in patients with acute renal impairment after cardiac surgery. This renal vasodilatory effect is maintained during a long‐term infusion and seems to be hemodynamically safe.
No impact of a leucocyte depleting arterial line filter on patient recovery after cardiopulmonary bypass
Authors: Sahlman A. , Ahonen J. , Salo J. A. , Rämö O. J.
Published: March 2003

Backround:

Contact of blood with foreign surfaces in the cardiopulmonary bypass (CPB) circuit induces an inflammatory response and immunosuppression which are associated with several organ dysfunctions following cardiac surgery. The aim of the present study was to evaluate clinical patient recovery after coronary artery bypass surgery (CABG) using CPB with leucocyte filtration or no arterial line filter.

Methods: Sixty patients scheduled for CABG were randomly assigned to undergo CPB with a leucocyte depleting arterial line filter (Pall LG6®) or no filter. Total leucocyte count and platelet count were determined before and after CPB. Values for blood urea nitrogen, serum creatine, serum sodium and potassium, serum osmolality, urine creatine, urine sodium and potassium, and urine osmolality were recorded at baseline, at 6 h and 24 h after CPB, and on the 5th postoperative day. Complement status was evaluated by measuring the levels of C3 and C4 before surgery and 24 h after CPB. Need for postoperative inotropic support was recorded, as was oxygen index prior to and after tracheal extubation. Times to awakening and tracheal extubation were noted, as were length of stay at the intensive care unit (ICU) and the hospital. Amount of chest drainage until 24 h and need for red blood cell transfusions were recorded.

Results: The level of C3 at 24 h was significantly lower in LG6®‐patients, but no further differences were detected between the groups in any of the laboratory or clinical parameters except for greater chest drainage in LG6®‐patients. However, need for red blood cell transfusions was similar in both groups.

Conclusion: Leucocyte filtration in our elective CABG patients did not have any impact on pulmonary gas exchange, need for postoperative inotropic support, length of postoperative mechanical ventilation, or length of ICU or hospital stay.
Impact of enteral feeding on gastric tonometry in healthy volunteers and critically ill patients
Authors: Rokyta Jr R. , Novák I. , Matějovič M. , Hora P. , Nalos M. , Šrámek V.
Published: March 2003

Background: Enteral feeding may interfere with gastric tonometry measurement. The effect of enteral nutrition on gastric tonometry has not been fully documented.

Methods: Seven healthy volunteers and nine stable intensive care unit (ICU) patients with poor tolerance of gastric feeding were investigated. Consecutive continuous postpyloric and gastric feeding, both at two different rates (40 and 100 ml  ·  h−1, respectively), and an intragastric 200 ml nutrition bolus were studied. Gastric intramucosal PCO2 (PiCO2) was measured by air tonometry and in patients a gastric intramucosal‐arterial PCO2 difference (PCO2 gap) was calculated. Hemodynamics and blood gases were also measured.

Results: In volunteers, PiCO2 remained stable during the postpyloric phase. During continuous gastric feeding PiCO2 did not change significantly, although in 4 volunteers PiCO2 increased >0.5 kPa. PiCO2 decreased significantly after gastric bolus from 6.9±0.4 to 6.1±0.5 kPa (P<0.05). Eight patients had an increased PCO2 gap (>1 kPa) at baseline (1.8±0.6 kPa). PCO2 gap changes during the whole study were not statistically significant. However, during the postpyloric phase (or immediately afterwards), the PCO2 gap increased by more than 0.5 kPa in 5 patients. After gastric bolus, a decrease in PCO2 gap >0.5 kPa was seen in 5 patients.

Conclusion: In volunteers, postpyloric feeding does not interfere with gastric tonometry measurement and gastric bolus leads to a PiCO2 decrease. The impact of postpyloric and gastric feeding on gastric tonometry in ICU patients with compromised gut is variable.
Ropivacaine 1 mg/ml, plus fentanyl 2 μg/ml for epidural analgesia during labour. Is mode of administration important?
Authors: Smedvig J. P. , Soreide E. , Gjessing L.
Published: March 2003

Background: Patient‐controlled epidural analgesia (PCEA) with a moderate to high concentration of bupivacaine in obstetrics has been shown to give comparable analgesia and even higher level of satisfaction compared to continuous epidural infusion. We hypothesised that the use of a very low concentration technique (ropivacaine/fentanyl) might result in excessive dosing in the PCEA group, more motor blockade and a negative impact on spontaneous delivery rate.

Methods: We conducted a randomised, double‐blind study of 60 nulliparous women at term comparing low concentration ropivacaine/fentanyl administered in either patient‐controlled or fixed continuous infusion mode. Parturients with known predictors of painful deliveries, i.e. breech presentation, primary induction of labour, were not included. Deliveries within 90 min from the start of epidural analgesia were omitted from the evaluation.

Results: We found that both groups required a mean of 12 ml/h low concentration mixture (loading and midwife rescue boluses included). There was no difference between groups with respect to spontaneous delivery rate (71%). This low concentration technique resulted in haemodynamic stability without crystalloid preloading, infusion or vasopressor use. Motor blockade of clinical importance was not detected in any patient.

Conclusion: We conclude that epidural use of ropivacaine 1 mg/ml+fentanyl 2 μg/ml provides effective analgesia with equal volume requirements irrespective of administration mode, with a high spontaneous delivery rate. Choice of PCEA or CEI (continuous epidural infusion) should be directed by other considerations, most importantly compliance of midwife and possible reduction in workload for anaesthesiology staff.
Coagulation assessment in healthy pigs undergoing single xenon anaesthesia and combinations with isoflurane and sevoflurane
Authors: Horn N. A. , Hecker K. E. , Bongers B. , Baumert H. J. , Reyle‐Hahn S. M. , Rossaint R.
Published: March 2003

Background: With the introduction of new anaesthetics into clinical practice possible side effects of these novel anaesthetics have to be evaluated. This study was performed to clarify whether xenon or combinations of xenon with isoflurane or sevoflurane modify blood coagulation.

Methods: The study was performed in 20 healthy pigs which first underwent xenon anaesthesia (65 Vol%) and were then randomly assigned to combinations of xenon and isoflurane or sevoflurane at varying concentrations. During anaesthesia the following parameters were controlled: aPTT, PT, fibrinogen concentrations and thrombelastographic measurements.

Results: Xenon monoanaesthesia did not alter significantly any coagulation parameter. When isoflurane was introduced the aPTT showed a significant increase while fibrinogen concentration decreased. The introduction of sevoflurane led also to a decrease in fibrinogen concentration, while the aPTT was unchanged. These decreases in fibrinogen concentration were not accompanied by reduced maximal clot strength or elevated fibrinolysis evaluated by thrombelastography. Although the above‐described changes were statistically significant, none of the parameters throughout the experiment exceeded the limits of normal values.

Conclusion: In our study, xenon monoanaesthesia and combinations of xenon with isoflurane and sevoflurane did not lead to pathologic alterations in the measured coagulation parameters.
Computerized tomography‐guided epidural blood patch in the treatment of spontaneous low cerebrospinal fluid pressure headache
Authors: Karst M. , Hollenhorst J. , Fink M. , Conrad I.
Published: March 2003

A 54‐year‐old woman suffering from migraine for 35 years was referred to the pain clinic with a changed pattern of headache that had developed over the last 6 weeks. The pain was located in the central forehead region; aggravation in the prone and immediate relief in the supine position led to the hypothesis of a spontaneous low cerebrospinal fluid (CSF) pressure headache. Cisternography revealed a cyst‐like formation in the cervico‐thoracic region, indicating cerebrospinal fluid leakage. Magnetic resonance imaging (MRI) myelography confirmed ventral leakage but failed to locate the exact site. Computerized tomography (CT)‐guided epidural blood patching between T1 and T2 completely relieved the headache.
Heart–lung interactions during positive pressure ventilation: left ventricular pressure–volume momentary response to airway pressure elevation
Authors: Haney M. F. , Johansson G. , Häggmark S. , Biber B.
Published: March 2003

Background: Left ventricular (LV) pressure and volume changes are known to occur in response to positive airway pressure (PAP). We aimed to further describe the immediate LV response to increased PAP as demonstrated in successive heart cycles with LV pressure and volume alterations. We postulated that these acute systematic LV events during institution of PAP can follow a distinct pattern that would allow calculation of parameters of systolic function, including end‐systolic elastance (Ees) and preload recruitable stroke work (PRSW). We also aimed to examine the relationship of PAP‐derived Ees and PRSW to the same parameters derived from vascular occlusion.

Methods: Eight anesthetized adult pigs were studied with invasive circulatory measurements including LV pressure and volume (conductance). The PAP intervention was an airway pressure plateau of 15 cm H2O for 6 s (APP). Venous occlusion was performed by transient balloon inflation in the inferior vena cava (IVCO). Ees and PRSW were derived for each APP and IVCO intervention.

Results: Central circulatory variables during APP and IVCO are reported. LV systolic function parameters could be derived from each of the heart–lung interactions during APP sequences. Ees and PRSW derived from APP showed a significant positive bias in relation to those derived from the IVCO sequence.

Conclusions: We conclude that the heart–lung interactions during APP of the magnitude and duration shown here can allow derivation of Ees and PRSW. These parameters are not interchangeable with Ees and PRSW derived from IVCO.
Always flush the sampling port before flushing the arterial cannula in pediatric patients
Authors: Weiss M. , Fischer J. E. , Neff T. , Hug M. I. , Baenziger O.
Published: March 2003

Background: Blood sampling from arterial lines is a frequent event in anesthesia and critical care. To avoid clot formation, both the stopcock outlet and the cannula must be flushed after sampling. We investigated in a bench experiment whether fluid flow through the cannula is affected by the sequence of flushing procedures.

Methods: Continuity of fluid delivery from a vascular cannula was gravimetrically determined using two different flushing techniques with either a syringe pump flush system or a bag flush system. The procedures comprised first flushing the stopcock towards the cannula and then towards the stopcock sampling outlet or the reverse order. Experiments were repeated in triplicate and two sets for each flushing system at hydrostatic pressures of 37 mm Hg and 74 mm Hg.

Results: The main finding of the study was that flushing the stopcock towards the outlet after flushing the cannula resulted in considerable retrograde aspiration volumes and zero flow times, in particular in combination with syringe pump flush systems. At a hydrostatic pressure of 74 mm Hg, the observed zero flow time at the cannula tip amounted to (mean±SD) 0.1±0.01 min with the bag flush system and 7.7±0.5 min with the syringe pump flush system. The related retrograde aspiration volumes were 2.2±0.7 μl with the bag system and 30.0±2.0 μl with the syringe pump system. No backflow was recorded when the stopcock was first flushed to ambient pressure and then afterwards towards the cannula.

Conclusion: Opening a flush system to ambient pressure affects the continuity of fluid delivery, particularly when using syringe pump flush systems. After blood sampling, the stopcock outlet should be flushed first followed by cannula flushing.
Ultrasound control for presumed difficult epidural puncture
Authors: Grau T. , Leipold R. W. , Conradi R. , Martin E.
Published: March 2003

Background: The efficacy of epidural anaesthesia depends on the accurate identification of the epidural space (ES). Abnormal anatomical conditions may make the procedure difficult or impossible. The aim of this study was to investigate whether pre‐puncture ultrasound examination of the spinal anatomy might be beneficial in expected cases of difficult epidural anaesthesia.

Methods: We used digital ultrasound equipment with a 5‐MHz transducer to assess the anatomy of the ES and the posterior parts of the spinal column. We examined 72 parturients with abnormal anatomical conditions who were scheduled for epidural anaesthesia. The women were randomised into two equal groups. In all patients, the standard loss of resistance technique was used. In the ultrasound group, an ultrasound examination of the appropriate spinal region was conducted prior to epidural puncture. ES depth seen on the ultrasound images was compared to the ES depth measured by the needle. We compared the number of puncture attempts with the standard method (control group) to the number of attempts under ultrasound guidance.

Results: Ultrasonography significantly improved operating conditions for epidural anaesthesia. The maximum VAS scores and patient acceptance were significantly better.

Conclusions: With ultrasound measurement of the ES depth, the quality of epidural anaesthesia was enhanced.
Posture‐related distribution of hyperbaric bupivacaine in cerebro‐spinal fluid is influenced by spinal needle characteristics
Authors: Mardirosoff C. , Dumont L. , Deyaert M. , Leconte M.
Published: March 2003

Background: No studies have evaluated the relationship between duration of time sitting and spinal needle type on the maximal spread of local anaesthetics. The few trials available have studied the influence of time spent sitting on the spread of anaesthesia without standardising spinal needle types, and have not found any effect.

Methods: In this randomised, blinded study, 60 patients scheduled for elective orthopaedic surgery of the lower limbs were divided into 4 groups. With the patient sitting erect, 15 mg hyperbaric bupivacaine were injected in a standard manner through a 24G Sprotte or a 27G Whitacre needle and patients were placed supine after 1 min (24G/1 group and 27G/1 group) or 4 min (24G/4 group and 27G/4 group).

Results: Time to achieve maximum block height after injection was similar in all groups. Block height levels were significantly lower at all time points for the 24G/4 group. Maximum block heights were Th4 in the 24G/1, 27G/1 and 27G/4 groups, and Th6 in the 24G/4 group (P<0.0001).

Conclusion: In a standard spinal anaesthesia procedure, when different lengths of time spent sitting are compared, spinal needle characteristics influence the maximum spread of hyperbaric bupivacaine. However, within the limits of our study, a two‐segment difference in block height is too small to consider using spinal needles as valuable tools to control block height during spinal anaesthesia in our daily practice.
Effects of hypertonic 75 mg/ml (7.5%) saline on extracellular water volume when used for preloading before spinal anaesthesia
Authors: Järvelä K. , Kööbi T. , Kauppinen P. , Kaukinen S.
Published: March 2003

Background: Prevention of hypotension during spinal anaesthesia is commonly achieved using fluid preloading. This may result in a substantial amount of excess free water retained in the body after spinal anaesthesia. We aimed to evaluate the effects of 7.5% hypertonic saline on extracellular water volume and haemodynamics when used for fluid preloading before spinal anaesthesia.

Methods: This randomised double‐blind study evaluated the effects of 75 mg/ml (7.5%) hypertonic saline (HS) on extracellular water volume and haematocrit in patients undergoing arthroscopy or other lower limb surgery under spinal anaesthesia. Amounts of 1.6 ml/kg of HS (20 patients) or 13 ml/kg of 9 mg/ml normal saline (20 patients) were administered for preloading before spinal anaesthesia with a 10 mg dose of 0.5% hyperbaric bupivacaine. Etilefrine was administered in order to maintain mean arterial pressure (MAP) at 80% of its baseline value. Whole‐body impedance cardiography‐derived cardiac index (CI) and extracellular water (ECW) were measured.

Results: There were no significant differences in demographic data or in the number of blocked segments. ECW remained similar in both groups despite the much smaller amount of infused free water in the HS group. There were no significant differences between the groups in CI values during the study. The amount of etilefrine administered was similar in the treatment groups. Dilution of haematocrit was also similar in both groups.

Conclusion: Hypertonic 75 mg/ml (7.5%) saline is an alternative for preloading before spinal anaesthesia in situations where excess free water administration is not desired. It is effective in small doses of 1.6 ml/kg, which increase the extracellular water, plasma volume and cardiac output, and thus maintain haemodynamic stability during spinal anaesthesia.
Sevoflurane mask induction of anaesthesia is associated with epileptiform EEG in children
Authors: Vakkuri A. , Yli‐Hankala A. , Särkelä M. , Lindgren L. , Mennander S. , Korttila K. , Saarnivaara L. , Jäntti V.
Published: March 2003

Background: Sevoflurane inhalation induction of anaesthesia is widely used in paediatric anaesthesia. We have found that this method is frequently associated with epileptiform electroencephalogram (EEG) in adults, especially if controlled hyperventilation is used.

Methods: We assessed EEG during sevoflurane inhalation induction in 31 children, aged 2–12 yr. Anaesthesia was induced with 8% sevoflurane in O2 in N2O 1:2. The patients were randomized to undergo controlled ventilation (CV group), or to breathe spontaneously (SB group) for 5 min. EEG was recorded as were noninvasive blood pressure and heart rate (HR). EEG recordings were classified by a clinical neurophysiologist.

Results: Three different types of interictal epileptiform discharge were detected. Suppression with spikes (SSP) was found in 25% and 0% in the CV and SB groups, rhythmic polyspikes (PSR) in 44% and 20%, and periodic epileptiform discharges (PED) in 44% and 0% (P<0.01), respectively. The incidence of all different types of interictal epileptiform discharge (SSP+PSR+PED) was 88% and 20% (P<0.001), respectively. Epileptiform EEG was associated with increased heart rate and blood pressure during anaesthetic induction.

Conclusion: Both ventilation modes produced epileptiform EEG. With controlled ventilation, epileptiform discharges were seen in 88% of children. This warrants further studies of the suitability of this induction type in general, and especially in children with epilepsy.
Thiopental directly depresses lumbar dorsal horn neuronal responses to noxious mechanical stimulation in goats
Authors: Sudo M. , Sudo S. , Chen X. G. , Piercy M. , Carstens E. , Antognini J. F.
Published: March 2003

Background: Thiopental has hypnotic actions in the brain, but it also depresses nociceptive transmission. In this study we examined whether thiopental had direct (spinal) and/or indirect (supraspinal) effects on the responses of single lumbar dorsal horn neurons to noxious mechanical stimulation, using a method to deliver thiopental differentially to either the torso or cranial circulation in goats.

Methods: Goats (n=10) were anesthetized with isoflurane and neck dissections performed to permit cranial bypass. A lumbar laminectomy was made to permit single‐unit recording of lumbar dorsal horn neuronal activity (1–2 neurons/animal). Isoflurane was maintained at 0.8±0.1% to both head and torso throughout the study. During cranial bypass, thiopental was separately administered to the torso (low dose, 1.5±0.5 mg/kg; high dose, 3.7±0.5 mg/kg) or cranial (low dose, 0.12±0.03 mg/kg; high dose, 0.2 mg/kg) circulation.

Results: Thiopental administered to the torso significantly depressed dorsal horn neuronal responses to noxious stimulation at the high dose: 757±471 to 392±305 impulses/min at 1 min post‐injection, P<0.006 (n=14); evoked responses recovered at 5 min post‐injection. At the low dose, there was a similar numerical decrease, but this did not reach significance: 876±780 to 407±499 impulses/min at 1 min post‐injection, P>0.05 (n=6). No significant change was observed when thiopental was administered to the cranial circulation: low dose, 1061±1167 to 965±874 impulses/min at 1 min post‐injection, P>0.05 (n=10); high dose, 864±331 to 917±525 impulses/min at 1 min post‐injection, P>0.05 (n=8).

Conclusion: Thiopental has a direct (spinal) depressant effect on dorsal neuronal responses to noxious stimulus, but no significant supraspinal effect.
Controlled hypercapnia during one‐lung ventilation in patients undergoing pulmonary resection
Authors: Sticher J. , Müller M. , Scholz S. , Schindler E. , Hempelmann G.
Published: March 2003

Background: In a pilot study, the haemodynamic and gas exchange effects of acute hypercapoia during one‐lung ventilation in thoracotomy patients were investigated. The effects of normocapnic one‐lung ventilation (OLV‐N) on haemodynamics and pulmonary gas exchange were compared with those of hypercapnic one‐lung ventilation (OLV‐H) in 14 patients undergoing pulmonary lobectomy.

Methods: Hypercapnia was induced by decreasing tidal volume until PaCO2 increased to 8–9 kPa. During OLV, minute ventilation was reduced from 8.8±1.7 to 4.2±0.7 l min−1.

Results: Cardiac index (from 3.3±0.6 to 3.9±0.6 l min−1, P<0.01) and pulmonary vascular resistance index (from 245±96 to 347±125 dyn s cm−5 m−2, P<0.05) increased during OLV‐H, whereas systemic vascular resistance index decreased from 1952±403 to 1636±361 dyn s cm−5 m−2 (P<0.01). Pulmonary oxygenation remained unchanged.

Conclusions: All patients had an uneventful course during OLV‐H. The determinants of pulmonary oxygenation during hypercapnic one‐lung ventilation remain to be further elucidated.
High‐dose flumazenil potentiates the hypnotic activity of propofol, but not that of thiopental, in ddY mice
Authors: Adachi Y. U. , Watanabe K. , Higuchi H. , Satoh T.
Published: March 2003

Background: Flumazenil is a specific benzodiazepine agonist, which is reported to have a partial benzodiazepine agonist‐like effect at a high dose. This study investigated the effects of flumazenil and midazolam on the hypnotic dose of propofol and thiopental in ddY mice, using a behavioral model.

Methods: Mice were given either propofol or thiopental intravenously to induce hypnosis, which was defined as a loss of the righting reflex. The mice were pre‐treated with flumazenil (0.05, 0.1, or 0.2 mg kg−1) or midazolam (0.1 or 0.2 mg kg−1), and given propofol or thiopental after a 30‐s delay.

Results: Pre‐treatment with flumazenil (0.1 or 0.2 mg kg−1) significantly decreased the hypnotic dose of propofol compared to the control group (9.3±0.39 [8.5–10.0] or 9.0±0.28 [8.5–9.6] vs. 10.8±0.42 [9.9–11.6] mg kg−1 (ED50±SEM and [95% confidence interval]) P<0.05), but not that of thiopental (9.1±0.30 [8.5–9.7] with 0.2 mg kg−1 flumazenil vs. 9.3±0.42 [8.4–10.1] mg kg−1 with saline). Midazolam reduced the hypnotic dose of both propofol and thiopental. Flumazenil antagonized the potentiating effect of midazolam (0.2 mg kg−1) on the hypnotic activity of propofol.

Conclusions: These results suggest that the hypnotic activity of propofol is potentiated by the partial agonist activity of flumazenil in ddY mice.
Determinants of ICU mortality in necrotizing pancreatitis: the influence of Staphylococcus epidermidis
Authors: Ala‐Kokko T. I. , Tieranta N. , Laurila J. , Syrjälä H.
Published: March 2003

Background: The severity of acute necrotizing pancreatitis ranges from self‐limited to rapidly progressive illness leading to multiple organ failure. Several scoring systems and clinical parameters have been used to predict the course of the disease. The aim of this study was to evaluate the clinical and microbiological determinants of poor outcome in necrotizing acute pancreatitis.

Methods: Medical records of 67 consecutive patients admitted to the intensive care unit (ICU) of Oulu University Hospital due to acute necrotizing pancreatitis were retrospectively analyzed. All patients received standard surgical intensive care.

Results: Patients who died (n=14) had significantly higher APACHE II, SAPS II and Ranson scores at admission to the ICU and maximum SOFA score achieved during ICU stay than did the survivors. The non‐survivors were hospitalized later from the time the symptoms were first manifest (5.3 vs. 2.4 days, P=0.051). Mechanical ventilation (P=0.002), surgical management (P=0.028), open packing surgical management (P=0.03), renal replacement therapy (P<0.001), use of inotropic drugs (P=0.012) and Staphylococcus epidermidis growth (P=0.029) in infected pancreatic tissue were all associated with mortality.

Conclusions: In this study the time to hospitalization, severity of illness, intensity of care, and surgical management were associated with poor outcome. In addition, Staphylococcus epidermidis in pancreatic necrosis was associated with increased mortality.