bluuebunny/crossref_metadata_2025_split huggingface dataset:
Unilateral changes of sympathetic tone to the heart impair left ventricular function
Authors: Schlack W. , Thämer V. 
Published: January 2009

Background. Different regions within the left ventricle are preferentially supplied by the left or right sympathetic system. In order to characterize different influences of left vs right sympathetic lateralization on LV function, haemodynamic effects of right and left stellate ganglion stimulations (RSGS and LSGS) as well as a right sympathetic block (RSB) were compared.Methods. Seven α‐chloralose anaesthetized open chest dogs were instrumented for measurement of LV pressure (tip manometers) and regional LV wall thickness (WT, sonomicrometry) in the ante‐ro‐apical wall (AW, innervated by right stellate ganglion) and posterobasal wall (PW, left stellate ganglion). Timing of regional myocardial wall motion was evaluated by the phase of the first Fourier transform of the WT signals, LV asynchrony by the phase difference (ψ) between both regions, and LV diastolic function by the time constant of isovolumic relaxation (τ). Measurements were performed before and after RSB (5 ml of lidocaine 1%); in 6 dogs of this group, RSGS and LSGS (4 V, 0.2 ms, 20 Hz) were performed before RSB. In order to investigate a regional inotropic stimulation without systemic effect, 6 additional dogs received intracoronary noradrenaline injections (NIC, 0.25 μg) into the left circumflex artery perfused myocardium.Results. LSGS and NIC led to an earlier PW‐motion within the cardiac cycle (phase reduction by 40.0±15.0° (SEM) and 55.5±11. 2°) and RSGS induced an earlier AW‐motion (by 33.7±15.2°). After RSB, AW‐motion was delayed (38.1±9.2°). The consequence was an asynchronous wall motion pattern after all interventions (change in ψ: LSGS ‐64.7±18.7°, RSGS 41.1±15.7°, NIC ‐74.5±17.4°, RSB ‐52.6±14.6°), and a prolonged relaxation (T increase: RSGS 9.4±1.9, NIC 8.3±1.5, RSB 3.7±0.8 ms).Conclusion. Unilateral increases as well as decreases of sympathetic tone to the heart result in an asynchronous wall motion pattern and an impaired LV relaxation.
Diffusion of anaesthetic gases through different polymers
Authors: Marx T. , Fröba G. , Bäder S. , Villwock J. , Georgieff M. 
Published: January 2009

Background. Improvement of working conditions and anaesthesia with closed systems includes reduction of gas leaks during anaesthesia. One source of contamination is the permeation of gases through plastic materials. The volume of gas permeating through a polymer depends on its molecular structure, the solubility and the diffusion coefficient.Methods. We designed an experimental set‐up to measure the permeation rates of nitrous oxide, enflurane and isoflurane through components of the anaesthetic ventilator made of silicone, latex, rubber and polyvinylchloride (PVC). Reservoir bags, ventilation tubes and endotracheal tubes were investigated.Results. The highest permeation rates of anaesthetic gases were observed with silicone materials. Permeation through silicone exceeded that of the least permeable material by more than 10.000 times. By summarizing the permeation rates of the single items, the use of silicone increases the anaesthetic system's leakage rate by 4 ml/min, which means an increase of 18% in a modern anaesthetic ventilator and of 31% in a closed system.Conclusions. The highest permeation rates were found for nitrous oxide through silicone, although nitrous oxide has a known low solubility in plastic materials. The result demonstrates the dependency of the leakage rate on the diffusibility. The leakage of anaesthetic gases caused by silicone items does not alone lead to unacceptable pollution of operating theatres. To minimize the total leakage rates of minimal‐flow‐systems, however, plastic materials with low solubility and low diffusion coefficients have to be used.
Small‐bowel obstruction and the effects of lidocaine, atropine and hexamethonium on inflammation and fluid losses
Authors: Nellgård P. , Jönsson A. , Bojö L. , Tarnow P. , Cassuto J. 
Published: January 2009

Background:The profuse fluid losses and morbidity of patients suffering from obstructive ileus are closely related to inflammatory changes in the obstructed bowel wall. Previous experimental studies have shown that use of steroids and NSAIDs can reduce fluid losses in obstructive ileus. In the present study, we investigated the effects of lidocaine on fluid losses since local anesthetics have been shown to possess wide and potent anti‐inflammatory properties. Hexamethonium and atropine were used to study the importance of the autonomic nervous system in bowel obstruction.Method:Experiments were performed in ratsin vivo. After 18 h of total obstruction of the jejunum by thread ligation, a segment of the obstructed jejunum was placed in a chamber with intact nervous and vascular supply and net fluid transport was continuously, registered by a gravimetric technique. Extravasation of Evans blue albumin as marker of inflammation was quantified byConclusion:Lidocaine significantly inhibited or prevented fluid losses when administered intravenously or topically to the obstructed gut. Mechanisms of action could be inhibition of nerve reflexes involved in fluid secretion and by inhibition of inflammation in the bowel wall. The inhibition of fluid losses by hexamethonium further supports the importance of the autonomic nervous system in the pathophysiology of bowel obstruction.
Extracorporeal membrane oxygenation (ECMO) as lung or heart assist
Authors: Bjertnaes L. , Vaage J. , Almdahl S. M. , Lil M. , Nilsen P. A. , Hansen K. , Solbø J. , Jolin Å. , Hotvedt R. , Olafsen K. , Bröndbo A. , Thoner J. , Gilbert M. , Hevrøy O. , Bjørsvik G. , Hesselberg N. , Bergland H. , Sivertsen O. 
Published: January 2009

Extracorporeal membrane oxygenation (ECMO) may serve as extracorporeal lung assist (ECLA) in patients with acute respiratory failure (ARF) or as extracorporeal heart assist (ECHA) in patients with low output syndrome (LOS) after open heart surgery. From 1988 to 1992 seven patients underwent ECMO in our hospital; four suffered from ARF and three from LOS. Various bypass techniques were employed. Two ARF patients, aged 58 and 18 years, had veno‐venous bypass; in the latter, ECMO was reinstituted as a veno‐arterial bypass one week after weaning. In a three‐year‐old boy, the ECMO outflow tubing was primarily connected to the pulmonary artery, and shortly afterwards relocated to the common carotid artery. In a 31‐year‐old man with ARF, and three LOS patients, a 56‐year‐old woman, and two men aged 68 and 70 years, ECMO was veno‐arterial with direct access to the ascending aorta. A heparin‐coated system was used, and all but one patient, who was treated with warfarin, received a daily low dose of heparin, which was withdrawn after from one to nine days.Six patients were weaned off ECMO after 4.5 to 21 days. Three ARF patients recovered completely; the child died. In one LOS patient, ECMO was withdrawn due to a poor general condition. Two others were weaned off ECMO and the intra‐aortic balloon pump, and the inotropic support was significantly reduced, but both died of multiple system organ failure. Although no firm conclusions can be drawn from these few case reports, the heparin‐coated system used as ECLA appears promising, whereas ECHA seems to imply a poor prognosis in patients who are not candidates for cardiac transplantation.
Safety aspects of delivery and monitoring of nitric oxide during mechanical ventilation
Authors: Westfelt U. Nathorst , Lundin S. , Stenqvist O. 
Published: January 2009

In the presence of oxygen NO is oxidised to NO2, which is toxic in higher concentrations.In this technical investigation, we evaluated a dosage system, modified from Stenqvist et al. 1993 (1), regarding NO and NO2 levels. NO was administered before the ventilator and NO2 scavenged using a soda lime absorber in the inspiratory limb close to the ventilator. NO/NO2 levels were measured using fuel cell technique. We tested the duration of soda lime scavenging, put in additional soda lime absorbers, used charcoal as absorber and exchanged tubing material. NO was delivered after the ventilator and we studied effects of interruption of ventilation.With concentrations of NO at or below 40 parts per million (ppm) at F1O2 0.9, NO2 levels were 1.2 pprn or lower. Corresponding values for 20 and 10 ppm were 0.4 and 0.2 ppm, respectively. Duration of the soda lime absorber was at least 72 hours. Additional soda lime absorbers did not further reduce NO2 levels. Charcoal absorbers reduced NO2, but also NO by 45% from set value. Tubing materials had no influence on NO and NO2 levels. When administering NO at the Y‐piece, levels of NO were increased by 35–60% and NO2 levels by 110–230%, compared to set values.Oxidation of NO to NO2 is continuously taking place in the breathing system. Doses of up to 40 pprn NO should be considered safe regarding NO2 levels. Administration of NO at the Y‐piece gives high and unpredictable levels of NO2.
Heparin‐coated circuits reduce the formation of TNFα during cardiopulmonary bypass
Authors: Yamada H. , Kudoh I. , Hirose Y. , Toyoshima M. , Abe H. , Kurahashi K. 
Published: January 2009

Background: Cardiopulmonary bypass (CPB) causes a systemic intlammatory response. TNFα, which is a major inflammatory mediator, has been found in the circulation during and after CPB. Although previous studies have shown that heparin coating of the extracorporeal circuits reduces complement and granulocyte activation, and the inflammatory response, the possible effect of heparin coating on TNFα formation and the inflammatory response has not been fully investigated.Methods: Eighteen patients scheduled for coronary artery bypass grafting were divided randomly into two groups. One group of patients had extracorporeal perfusion using heparin coated circuits (HC group, n = 9). The other group had extra‐corporeal perfusion using an identical circuit that was not coated (UC group, n = 9). Blood samples were drawn before, during, and after CPB for measurement of plasma TNFα, plasma IL‐8, neutrophil count, and neutrophil elastase.Results: Plasma levels of TNFα increased during CPB in the UC group but not in the HC group. Plasma concentrations of IL‐8 increased similarly during and after CPB in both groups. Coating the circuits with heparin did not affect the levels of IL‐8. In both groups, the neutrophil count increased after the release of the aortic cross clamp and remained elevated for three days. In the HC group, however, the increase of neutrophil count was significantly lower compared with the UC group. Plasma concentrations of neutrophil elastase were significantly increased during and after CPB in both groups. However, the levels of elastase were significantly lower at certain time points in the HC group.Conclusion: From these observations, we conclude that heparin coating of the extracorporeal circuits reduces the TNFα formation during CPB, which may reduce neutrophil activation.
Lidocaine attenuates hyperoxic lung injury in rabbits
Authors: Takao Y. , Mikawa K. , Nishina K. , Maekawa N. , Obara H. 
Published: January 2009

Background:High concentrations of oxygen acute lung injury. Neutrophils are thought to play a pivotal role in the pathogenesis of this lung injury through the release of oxygen radicals, neutral proteases, and lysosomal enzymes. Lidocaine has been shown to inhibit neutrophil function. We examined whether intravenous pretreatment with lidocaine attenuated acute lung injury induced by hyperoxia.Method:Twenty‐seven anaesthetized male rabitts were allocated to receive one of three treatments (n = 9 for each group): ventilation with 100% oxygen for 36 h with and without lidocaine treatment, and ventilation with air for 36 h without lidocaine. In the lidocaine‐treated group, a single intravenous lidocaine 2 mg/kg was administered immediately after the initiation of exposure to 100% oxygen;Results:Pure oxygen for 36 h caused no significant changes in haemodynamics, lung mechanics, or PaO2/FiO2ratio. However, hyperoxia significantly increased the lung W/D weight ratio, the influx of neutrophils into the lung, and BALF concentrations of C3a, C5a, TNF‐α, IL‐1β, and albumin. Lidocaine attenuated these increases (W/D ratio: 5.7vs5.1, %PMN: 19.2%vs1.6%, C3a: 62 ng/dlvs14 ng/dl, C5a: 7.9 ng/dlvs4.1 ng/dl, TNF‐α: 25 fmol/mlvs2.8 fmol/ml, IL‐1β: 36 fmol/mlvs2.2 fmol/ml, and albumin: 9.5 mg/dlvs2.8 mg/dl, all:P<0.05). The chemiluminescence was increased in hyperoxic compared with in normoxic rabbits and lidocaine treatment attenuated the increase (opsonized zymosan stiluated: 3.7×106cpmvs2.3×106cpm,P<0.05). Exposure to 100% oxygen caused extensive morphologic lung damage which was lessened by lidocaine (lung injury score (mean): 3vs4,P<0.05).Conclusion:These findings suggest that intravenous lidocaine has a prophylatic effect on initial hyperoxic lung injury (pulmonary vascular permeability, histopathological, and biochemical BALF changes) in rabbits. The effects of lidocaine on more severe lung injury (decreased oxygenation) caused by hyperoxia for 72 h deserve further study.
Patient‐controlled premedication by iv midazolam for ambulatory surgery
Authors: Bernard J‐M. , Faintreny A. , Lienhart A. , Souron R. 
Published: January 2009

Applying the principle and equipment of patient‐controlled analgesia, this double‐blind randomised study was designed to determine the premedication dose of midazolam and to provide information about the need for preoperative anxiety control.The effects of patient‐controlled premedication by iv midazolam were compared to those of a 1‐hour iv infusion of a fixed dose of 4 mg. Two groups of 25 patients were studied prior to ambulatory surgery. Using a visual analogue scale graded from 0 (no anxiety) to 100, anxiety and short‐term memory as well as vital signs, vigilance, cognition and orientation were assessed before premedication and then every 20 min until admission to the operating room.In both groups, 40% of the patients were free of anxiety before prernedication. Sixty‐four percent of patients in the self‐premedicated group never used the pump. The dose of midazolam was only 0.7 0.2 mg (mean SD) in this group taken as a whole, 0.7 1.1 mg (mean SD) in the 8 patients who had an anxiety score at least equal to 50 before premedication, and 1.7 0.3 mg (mean SD) in the 9 patients who chose to push the button of the patient‐controlled device. Anxiety and short‐term memory scores decreased significantly and similarly in the self‐prernedicated group and in the fixed‐dose group. For similar intraoperative anaesthetic requirements, time from the end of anaesthesia for determining whether a patient was ready for admission to the postrecovery lounge was shorter in the self‐premedicated group (26±8 min vs 32±8 min; mean±SD. Reduced doses of midazolam self‐administered via a patient‐controlled device can result in a relaxed preoperative period and amnesia in ambulatory surgery patients. However, the level of anxiety before prernedication was low, which calls into question the legitimacy of the patient‐controlled premedication in this kind of population. The expense of the pump was not justified by the small number of patients using it, probably because they were worried by the technical nature and the invasiveness of this technique.
In vitromyocardial depression by ketamine or thiopental is dependent on the underlying beta‐adrenergic tone
Authors: Thurston T. A. , Mathew B. P. 
Published: January 2009

Background:Depression of myocardial contractility by muscarinic stimulation is dependent on the underlying beta‐adrenergic tone. Prior beta‐adrenergic stimulation enhances muscarinic negative inotropic responses, an effect that has been termed accentuated antagonism. The purpose of this study was to determine whether accentuated antagonism occurs with myocardial depression caused by thiopental or ketamine.Methods:Using an isolated, electrically stimulated rat left atrium model, the dose‐response curves to the muscarinic agonist carbachol and the anesthetics ketamine and thiopental were compared under conditions of high (10‐6M isoproterenol bath concentration) or low (10‐6M propranolol) beta‐adrenergic tone.Results:As expected, depression by carbachol was accentuated in preparations stimulated with isoproterenol compared with atria treated with propranolol. The decrease in tension by high doses (>400 μM thiopental, >200 μM ketamine) of thiopental or ketamine was attenuated in isoproterenol‐stimulated tissue when compared with beta‐adrenergic blocked muscle. Low concentrations (200 μM thiopental, 100 μM ketamine) of anesthetic caused either no change in contractility (thiopental) or small positive inotropic responses (ketamine) in propranolol‐treated but not isoproterenol‐stimulated tissue.Conclusions: In contrast to muscarinic agonists, myocardial depression by high concentrations of ketamine or thiopental is attenuated by prior beta‐adrenergic stimulation. Positive inotropic responses may be seen with low concentrations of ketamine in muscle with low beta‐adrenergic tone. The results of this study demonstrate that the underlying beta‐adrenergic tone greatly influences thein vitroresponse of cardiac tissue to ketamine or thiopental.
The effect of continuous epidural infusion of ropivacaine (0.1%, 0.2% and 0.3%) on nerve conduction velocity and postural control in volunteers
Authors: Zaric D. , Nydahl P.‐A. , ÄDel S.‐O. , Enbom H. , Magnusson M. , Philipson L. , Axelsson K. 
Published: January 2009

Background: Continuous epidural infusions of local anaesthetics have become increasingly popular in postoperative pain treatment, especially as they permit early mobilisation. Ropivacaine is a promising new agent which induces more pronounced sensory than motor blockade. This study was focused on the influence of continuous epidural infusion of ropivacaine on impulse conduction in large nerves (by measurement of F and H latencies), and on the subjects' ability to maintain postural control during mobilisation.Methods: Healthy male volunteers received 0.1%, 0.2% or 0.3% ropivacaine, and bupivacaine 0.25% was used as reference. A bolus epidural injection of 10 ml of the drug, at L2/3 level, was followed by continuous infusion at 10 ml/h for 21 h. Motor blockade was assessed by mechanical measurements of force during big toe flexion and by recording of F latency. Sensory blockade was monitored by pin‐prick and Thermotest methods, and by H latency recording. The subjects' ability to perform a postural test was evaluated by posturography.Results: The F and H latencies became prolonged/abolished dose‐dependently. With ropivacaine, F latency recovered significantly later than motor function (P = 0.0002), and H latency recovered later than normal pin‐prick perception (P = 0.0006). However, the duration of partial blockade of thermopercep‐tion was comparable to that of H latency prolongation. Posturographically, the subjects receiving 0.1% ropivacaine differed significantly from all others (P<0.001) in that they were able to maintain postural control during the infusion. The recovery period after termination of infusion was significantly shorter with ropivacaine than with bupivacaine for all measured variables.Conclusion: Recovery of postural control with 0.2% and 0.3% ropivacaine is significantly faster than with bupivacaine 0.25%. H latency recording allows detection of epidural blockade intensity that does not prevent subjects from performing postural tests.
Is preoperative ketorolac a useful adjunct to regional anesthesia for inguinal herniorrhaphy?
Authors: Ben‐David B. , Baune‐Goldstein U. , Goldik Z. , Gaitini L. 
Published: January 2009

Background: Nonsteroidal antiinflammatory drugs (NSAIDs) have become a popular component of analgesia regimens, particularly in combination with narcotics. We questioned whether there might also be a place for their use in conjunction with regional anesthesia and whether there was a preferable route for NSAID administration.Methods: Ilioinguinal and field blocks were performed pre‐operatively on seventy patients undergoing outpatient inguinal hernia repair. Patients were divided into a control group who received no ketorolac and four study groups who received a preoperative dose of 30 mg ketorolac by one of the following routes: IV, IM, PO, or intrawound (IW). The ketorolac in the IW group was mixed in the syringe with the local anesthetic used for the field block. IV and IM groups also received ketorolac at the time of the preoperative regional anesthesia and the PO group received the dose at least one hour preoperatively. All patients received a similar general anesthetic intraoperatively.Results: Postoperative pain scores and analgesic requirements were lowest for the IM, IV, and IW groups. Pain scores and analgesic requirements for the PO group were less than for the control group but more than for the other three groups. Analgesic efficacy therefore ranked: IM = IV = IW>PO>Control.Though no differences were found between groups in the time to discharge from the recovery room, the ease of nursing care paralleled the findings for pain scores and analgesia requirements.Conclusion: Beyond the analgesia provided by the regional anesthesia of the ilioinguinal and field blocks, the preoperative use of ketorolac further reduced postoperative pain scores and the need for additional postoperative analgesic medication. Comparable outcomes for the IV, IM, and IW groups indicate the lack of any benefit to concentrating the non‐steroidal anti‐inflammatory drug at the wound (IW) or to achieving high blood levels rapidly (IV). In conclusion, ketorolac is a useful supplement to ilioinguinal plus field block regional anesthesia for hernia surgery and is most effective administered parenterally.
Menstrual stage influences postoperative nausea and vomiting following epidural buprenorphine
Authors: Kitamura A. , Kon T. , Kamiyama M. , Ggawa R. 
Published: January 2009

Background: Although buprenorphine sometimes causes severe emesis, its relation to the menstrual cycle has not been reported.Methods: We conducted a prospective study on 68 reproductive‐age women following lower extremity surgery under epidural anesthesia plus buprenorphine, to assess the effect of the day of the menstrual cycle on the incidence of postoperative nausea and vomiting. The patients were divided according to the phase of the menstrual cycle into four groups: day 1–7 group, day 8–14 group, day 15–24 group and day 25 to end of the cycle group.Results: Nausea and vomiting were reported in 46 patients (67.6%), and the incidence was higher in the day 25 to end of the cycle group than in the day 8–14 or day 15–24 groups, and higher in the day 1–7 group than in the day 8–14 group.Conclusion: We conclude that emesis after epidural buprenorphine is related to the menstrual cycle.
Effect of P‐6 acupressure on prevention of nausea and vomiting after epidural morphine for post‐Cesarean section pain relief
Authors: Ho C.‐M. , Hseu S.‐S. , Tsai S.‐K. , Lee T.‐Y. 
Published: January 2009

Background:Nausea and vomiting are important side effects following administration of epidural morphine for post‐Cesarean section pain relief. Stimulation of the P‐6 (Neiguan) acupoint is a traditional Chinese acupuncture modality used for antiemetic purpose; it has been found to be effective. The aim of this study was to evaluate the antiemetic effect of P‐6 acupressure in parturients given epidural morphine for post‐Cesarean section pain relief.Method:In a randomized, double‐blind and controlled trial, sixty parturients receiving epidural morphine for post‐Cesarean section pain relief were investigated. Parturients were allocated to receive the acupressure bands or placebo bands on the P‐6 acupoint bilaterally before the administration of spinal anesthesia and were observed over a 48‐hour study period.Results:The incidence of nausea and vomiting was significantly decreased from 43% and 27% in the control group, to 3% and 0% in the acupressure group, respectively (P<0.05).Conclusion:The results demonstrate that prophylactic use of acupressure bands bilaterally on the P‐6 acupoint can significantly reduce incidence of nausea and vomiting after epidural morphine for post‐Cesarean section pain relief.