bluuebunny/crossref_metadata_2025_split huggingface dataset:
In vivo effects of halothane, enflurane, and isoflurane on hepatic sinusoidal microcirculation
Authors: GRUNDMANN U. , ZISSIS A. , BAUER C. , BAUER M. 
Published: January 2009

Background: It has been proposed that halogenated anaesthetics interfere with the endothelium‐dependent circulatory control by attenuating the effects of endothelium‐derived relaxing factor (EDRF/NO). This study was designed to determine whether or not volatile anaesthetics in vivo influence the microvascular tone in hepatic sinusoids.Methods: Using epifluorescence videomicroscopy, we compared the effects of the volatile anaesthetics halothane, enflurane, and isoflurane on hepatic microcirculation in ventilated Lewis rats. Animals were initially anaesthetized with pentobarbitone (50 mg‐kg‐1 i.p.) to allow instrumentation and laparotomy and were randomly allocated to one of 4 groups (n=5–6 each) to receive either a supplementary dose of i.v. pentobarbitone (25 mg kg‐1; control group) or 0.75 MAC halothane, enflurane or isoflurane (1.5 MAC h).Results: Halothane decreased significantly the volumetric blood flow as compared with isoflurane (P < 0.05) or pentobarbitone controls (P < 0.05). The decrease in sinusoidal blood flow caused by halothane was largely attributable to a decrease in sinusoidal diameter (P < 0.05), while red blood cell velocity remained unchanged. Isoflurane led to a significant decrease in sinusoidal width compared with controls (P < 0.05) but an increase in red cell velocity offset the effect of sinusoidal narrowing on volumetric blood flow, while enflurane had no significant effect on any of the measured parameters.Conclusion:This study provides the first direct evidence that the volatile anaesthetics halothane and isoflurane in vivo shift the hepatic microvascular tone toward a more constricted state; however, flow velocity is enhanced with isoflurane, offsetting this effect. As a result the volumetric flow is at least affected by isoflurane, then enflurane and most significantly by halothane. Furthermore, our data are consistent with the concept that volatile anaesthetics in clinically relevant concentrations may influence the balance between endothelium‐derived vasoactive factors which control microvascular tone.
Lidocaine‐induced hemodynamic effects are enhanced by the inhibition of endothelium‐derived relaxing factor in dogs
Authors: TOYOYAMA H. , YUKIOKA H. , HAYASHI M. , TATEKAWA S. , FUJIMORI M. 
Published: January 2009

Background:Lidocaine has been shown to have direct vasoconstrictive effects at low concentrations. Since lidocaine inhibits endothelium‐dependent vasodilationin vitro, the vasoconstrictor effect of lidocaine may be due to inhibition of endothelium‐derived relaxing factor(EDRF/NO). Therefore, the current study was designed to determine the effects of NG‐nitro‐L‐arginine (L‐NNA), a potent inhibitor of nitric oxide synthase, on systemic and pulmonary hemodynamics during lidocaine infusion.Methods:Systemic and pulmonary hemodynamic effects of lidocaine infusion, 1 mg kg‐1min‐1, for 10 min were measured in dogs anesthetized with 1% halothane in oxygen. Dogs were studied twice with an interval of 1 week in a cross‐over study, and were assigned to one of two groups that received saline or L‐NNA intravenously in group 1 (n=8), or L‐NNA or L‐NNA+L‐arginine which reverses the nitric oxide synthesis inhibitor effect of L‐NNA, intravenously in group 2 (n=8) prior to lidocaine infusion. The free serum concentration of and protein‐binding ratio for lidocaine were measured.Results:With saline pretreatment in group 1, lidocaine infusion significantly decreased cardiac index (CI) and significantly in‐Conclusion:In contrast toin vitrostudy, vasoconstrictor effect of lidocaine is enhanced when a capacity for compensatory vasodilation including EDRF/NO pathway is exhausted in halo‐thane‐anesthetized dogs.
2‐chloroprocaine antagonism of epidural morphine analgesia
Authors: KARAMBELKAR D. J. , RAMANATHAN S. 
Published: January 2009

Background: 2‐chloroprocaine (2‐CP) used for lumbar epidural anesthesia (LEA) reportedly decreases the efficacy of epidural morphine (EM) administered for post‐cesarean section (CS) analgesia. The amount of supplemental i.v. morphine self‐administered by the patient via the patient‐controlled analgesia device (PCA) is used to study the interaction between EM and 2‐CP.Methods: Forty‐two patients scheduled for elective CS were randomly divided into 3 equal groups, and received 2‐CP, 2‐CP+epinephrine (Epi, 5 μg ml‐1) or 2% lidocaine (Lido) with Epi for LEA. All patients received 5 mg EM and i.v. PCA morphine for postoperative pain. Cumulative amount of i.v. morphine used in the first 24 hours as well as the amount of the drug used during each 2‐h period were noted. Nonparametric analysis of variance and Chi‐squared analysis were used for statistical comparisons.Results: The mean cumulative 24‐h i.v. PCA morphine requirement in the 2‐CP, 2‐CP+Epi and Lido+Epi groups respectively was 20.5±24, 33.1.5±27 and 4.07±6.3 (mean±SD). The Lido+Epi group used significantly less morphine (P = 0.01) compared to either of the 2‐CP groups with no significant difference between the 2‐CP groups. The maximum i.v. PCA morphine use occurred in the first 4 hours following surgery in all three groups.Conclusion: Analgesic efficacy of EM is decreased when 2‐CP is used for LEA compared to when Lido+Epi is used.
Time course of subjective pain ratings, and wound and leg tenderness after hysterectomy
Authors: MØINICHE S. , DAHL J. B. , ERICHSEN C‐J. , JENSEN L. MEINERT , KEHLET H. 
Published: January 2009

Background: Little information is available on time course of wound tenderness and relationship to subjective pain ratings following surgery. Furthermore, it is not clarified whether surgical procedures may induce hyperalgesia to mechanical stimulation outside the area of the surgical incision. We have therefore assessed postoperative pain and pressure pain thresholds (PPT) adjacent to and remote from the surgical incision in 16 patients undergoing hysterectomy.Methods: Pressure pain threshold was assessed with pressure algometry preoperatively, 4 and 6 h and 1, 4 and 8 d after surgery on the abdominal wall 0.5, 5, 10 and 15 cm perpendicular to the wound, and on the anterior surface of the left thigh and tuberositas tibia. Furthermore, pain was assessed on a visual analogue scale (VAS) at rest and during cough.Results: PPT decreased significantly 0.5, 5, 10 and 15 cm from skin incision up to 96 h after surgery (P < 0.01) with a trend towards higher PPT with increasing distance from the wound. There was no significant changes in PPT on the thigh or the tuberositas tibia (P = 0.49 and P = 0.12) and no correlation be tween changes in PPT near the wound and in remote areas (the legs) (Rs=‐0.082, P = 0.44 and Rs=‐0.0664, P = 0.53, respectively). VAS at rest increased from 4 to 24 h and the cough values, remained elevated throughout the study (P < 0.05). An inverse relationship was observed between PPT 5 cm from the incision and VAS at rest (Rs=‐0.406, P = 0.0002) and during cough (Rs=‐0.398, P = 0.0002).Conclusion: These results indicate that wound pressure algometry correlates to postoperative pain at rest and during movement and may be an alternative way of assessing wound pain and tenderness. Increased tenderness to mechanical stimulation remote from the surgical wound could not be demonstrated.
Uptake of inhaled nitric oxide in acute lung injury
Authors: WESTFELT U. NATHORST , LUNDIN S. , STENQVIST O. 
Published: January 2009

Background: Despite the widespread use of inhaled nitric oxide (NO), little is known of its pulmonary uptake in patients with acute respiratory failure.Methods: Fourteen patients with acute lung injury (ALI) and ongoing NO therapy were studied. Three doses of NO (5, 10 and 40 ppm) were given for 20 min and at each dose level the following parameters were recorded: minute ventilation, inspiratory NO cone, mixed expired NO cone, end‐tidal NO cone, mixed expired CO2 cone, end‐tidal CO2 cone and arterial CO2 tension. Total uptake was calculated and correlated to the total amount of NO inhaled, the amount of NO administered to the alveolar space, and the amount of NO administered to the perfused alveolar space.Results: About 35% of the total amount of NO delivered is taken up by the lungs, 70% of NO administered to the alveolar space is taken up, and 95–100% of the NO administered to perfused alveolar space is taken up. The size of the alveolar dead space varied between 10 and60% of the alveolar space. At 40 ppm of inhaled NO there was no difference between inspired and mixed expired NO2 concentration, indicating that there is no significant NO2 formation taking place in the lungs during NO inhalation at the concentrations studied.Conclusions: Practically all NO administered to the perfused alveolar space is taken up. The total uptake differs from that of healthy persons probably because of differences in the alveolar dead space.
Vitamin A exerts potential therapeutic effects in the endotoxaemic pig
Authors: ERIKSSON M. , LUNDKVIST K. , LARSSON A. , NELSON D. , SALDEEN T. , DROTT P. , ERIKSSON O. 
Published: January 2009

Background: Pretreatment with an injection of vitamin A has beneficial effects on cardiac and pulmonary functions in normally bred endotoxaemic pigs. The present study was performed in order to elucidate whether the response of an ongoing infusion of E. coli can be modulated by a single injection of vitamin A.Methods: Sixteen healthy (not vitamin A‐depleted) pigs were anaesthetized, monitored, mechanically ventilated and subjected to an infusion of E. coli endotoxin (10 μg kg‐1 h‐1). This infusion resulted within 30 min in a progressive haemodynamic derangement. When the mean pressure in the pulmonary artery was twice the baseline value, vitamin A (460 IU kg‐1) or a corresponding volume of vehicle was injected intravenously. After sacrificing the animals, the right lung was excised and weighed, and biopsy specimens were taken from the left lung for microscopical examination.Results: Mean arterial blood pressure was significantly less affected (P < 0.01) between the 1st and 6th hour in endotoxaemic pigs treated with vitamin A than in those given vehicle. The mean lung weight in the vitamin A‐treated pigs was significantly lower than that in the vehicle group (164±5.3 vs 199±19.8 g; P < 0.01). Microscopical examination showed significantly less oedema (0.93±0.17 vs 2.00±0.26; P <0.01) and microatelectasis (0.56±0.17 vs 1.75±0.31; P < 0.01) in the vitamin A group. Endo‐toxaemia was also accompanied by an initial, steep decline in neutrophil counts in all animals; this decrease was significantly less pronounced (P < 0.05) in vitamin A‐injected pigs than in the vehicle‐injected group. The major difference was a more rapid restitution in the vitamin A group.Conclusion: Several manifestations of endotoxaemia were expressed less in the vitamin A group. Thus, vitamin A may turn out to be a tool in the management of endotoxaemia.
Effects of open heart surgery on oral mucous host defence systems
Authors: LÄHTEENMÄKI M. , TENOVUO J. , SALO M. , PERTTILÄ J. 
Published: January 2009

Background: The immune response is affected by anaesthesia and surgery. This study was carried out on the effects of open heart surgery on the oral mucous host defence system, which is part of the common mucosal immune system.Methods: Amylase, nonimmunological (lysozyme, myeloperoxidase, hypothiocyanite and thiocyanate) and immunological (IgA, IgG, and IgM) mucous host defence factors as well as oral bacterial flora were determined in the saliva of 18 patients undergoing open heart surgery preoperatively and on the 2nd, 3rd, and 7th postoperative days. To assess the specificity of the changes, the salivary flow rate and total protein content were also determined.Results: Stimulated salivary flow decreased from 1.8 (1.3–2.2) ml/min (median; 25th and 75th quartiles) to 0.4 (0.3–0.5) ml/ min by the 2nd postoperative day and to 0.4 (0.2–1.0) ml/min by the 3rd postoperative day (P <0.001). Amylase, lysozyme, myeloperoxidase, total salivary peroxidase and thiocyanate levels increased, whereas hypothiocyanite levels decreased postoperatively (P < 0.01–0.001). Their total secretion rate, however, was reduced (P <0.05–0.001) owing to the lowered salivary flow rate. IgG and IgM concentrations were raised on the 2nd, 3rd and 7th postoperative days (P< 0.05–0.001), and IgA concentrations on the 2nd postoperative day (P <0.05). The total secretion of IgG and IgM as well as their salivary concentrations in relation to total protein concentrations also increased. The number of salivary anaerobically growing bacteria decreased postoperatively (P < 0.01), but the number of salivary streptococci remained unaffected.Conclusions: Open heart surgery decreases the salivary secretion of nonimmunological host defence factors and increases the salivary secretion of IgA, IgG and IgM.
Effects of hypothermia and sternal retractors on median nerve somatosensory evoked potentials
Authors: PORKKALA T. , KAUKINEN S. , HÄKKINEN V. , JÄNTTI V. 
Published: January 2009

Background: Somatosensory evoked potentials (SEPs) are altered by hypothermia, which is often used during cardiopulmonary bypass (CPB). However, the effect of hypothermia on SEP amplitudes is unclear. Also, the sternal retractors used during open heart surgery are reported to cause brachial plexus distension and SEP changes.Methods: Median nerve SEPs under hypothermic CPB were studied in 29 elective patients scheduled for open heart surgery. In 23 patients who underwent left internal mammary artery (IMA) dissection, the effects of sternal retractors on cortical SEP before the initiation of CPB were investigated.Results: A latency shift of all SEP components was detected when nasopharyngeal temperature decreased from 35.7(SD 0.4)°C to 27.8(SD 0.25)°C. The mean cortical N20 latency was increased by 39% (P< 0.0001), cervical N13 by 33% (P < 0.0001), and peripheral N9 by 27% (P <0.0001). The latency changes were reversible when normothermia was restored. The effect of hypothermia on SEP amplitudes was more complex. The mean amplitude of N20 decreased from 2.7 μV to 2.2 μV (P < 0.05) and the amplitude of N13 from 2.5 μV to 2.0 μV (P < 0.0001). In contrast, the N9 component showed an increase from 1.4 μV to 2.1 μV (P <0.0001) during hypothermia. The sternal retractors did not cause significant cortical SEP amplitude changes during IMA dissection or sternotomy. Also, the latency changes were small, although significant (P < 0.05).Conclusion: Despite the moderate amplitude changes produced by hypothermia, SEPs can be successfully monitored during hypothermia. Theoretically, the different behaviour of amplitude in peripheral and cranial components of SEP during hypothermia is interesting. Hypothermia has a more profound effect on synaptic transmission, represented by the cortical N20 latency, than on the peripheral nerve conduction velocity. Intraoperative monitoring of temperature is essential whenever SEPs are recorded. The sternal retractors were not responsible for the intraoperative SEP changes.
The influence of anaesthetic techniques and type of delivery on peripartum serum interleukin‐6 concentrations
Authors: JONGH R. F. DE , BOSMANS E. P. , PUYLAERT M. J. , OMBELET W. U. , VANDEPUT H. J. , BERGHMANS R. A. , MAES M. , HEYLEN R. J. 
Published: January 2009

Background: Interleukin‐6 is a pleiotropic cytokine with a wide range of physiological activities. It plays an important role in the immuno‐neuro‐humoral axis during stress and surgery.Methods: Serum interleukin‐6 in parturients was measured on hospital admission, immediately after birth and 12 and 24 hours later. All parturients had uncomplicated pregnancies, and delivered vaginally without (n=31) or with (n=20) epidural analgesia, or underwent Caesarean section under epidural (n=20) or general (n=10) anaesthesia.Results: Serum interleukin‐6 assayed immediately following Caesarean section was low, but peaked 12 hours later, irrespective of the anaesthetic technique or other foetomaternal characteristics. Patients who delivered vaginally showed the highest interleukin‐6 levels immediately after delivery. These were positively correlated with serum interleukin‐6 on admission and duration of labour. Serum interleukin‐6 was significantly higher in parturients who had epidural analgesia, and was significantly lower in those receiving intravaginal prostaglandins compared to those without prostaglandins.Conclusion: The interleukin‐6 response after Caesarean section can be explained by a generalized acute phase response to surgery, with no anaesthetic, maternal or neonatal interference. The rapid increase in peripartum serum interleukin‐6 levels after vaginal delivery reflects, in part, cervical ripening or labour, their physiological triggers and psychological or physical stress. Regional anaesthesia, duration of labour and exogenous prostaglandin administration can modulate the peripartum interleukin‐6 response and subsequently the physiological effects of this cytokine.
Continuous low‐flow tracheal gas insufflation during partial liquid ventilation in rabbits
Authors: MESZAROS E. , OGAWA R. 
Published: January 2009

Background: Both partial liquid ventilation (PLV) and tracheal gas insufflation are novel techniques for mechanical ventilation. In this study we examined whether PLV superimposed by continuous low‐flow tracheal gas insufflation (TGI) offers any advantage to the blood gases and lung mechanics in normal‐lung rabbits compared to the use of PLV only.Methods: Eighteen anesthetized, paralyzed and mechanically ventilated rabbits were used. After obtaining a baseline PaCO2value between 29 and 39 mmHg (3.9 and 5.2 kPa), the animals were assigned to three equal groups according to the ventilation they received ‐ A group: PLV superimposed by TGI; B group: PLV only; and C group: continuous mandatory ventilation (CMV) superimposed by TGI. Serial arterial blood gases, pH and lung mechanics were measured.Results: The animals in each group were hemodynamically stable. In the case of the A group, PaO2 continuously increased, and PaCO2 stabilized around 40.8±5.5 mmHg (5.4±0.7 kPa, mean±SD, NS). In the B group, the tendency for PaO2 to increase was not as definite; PaCO2 continuously increased from 35.2±2.3 mmHg (4.7±0.3 kPa) to 56.3±12.7 mmHg (7.5±1.7 kPa, P< 0.05) at the end of the experiment. In the C group, PaO2 and PaCO2 were stable during the observation period. The superimposition of TGI on PLV did not decrease the airway pressures compared to PLV alone.Conclusion: In summary, continuous low‐flow TGI superimposed on PLV can decrease and stabilize the PaCO2 elevation caused by the initiation of PLV.
Postoperative epidural infusion of morphine and bupivacaine is safe on surgical wards
Authors: RYGNESTAD T. , BORCHGREVINK P. C. , EIDE E. 
Published: January 2009

Background: There was an obvious need to improve the quality and safety of our postoperative pain treatment and to introduce an improved routine service on surgical wards.Methods: It was decided to use postoperative epidural infusion of morphine 0.04 mg/ml and bupivacaine 2.5 mg/ml (0.25%): 4–8 ml/h as pain relief after major surgery. An education programme was run emphasising the benefits, side‐effects and the importance of regular monitoring of pain intensity, vital functions (respiratory rate, blood pressure, heart rate), motor function of the legs and the need for additional drugs in order to detect side‐effects as well as lack of adequate analgesic effect. A detailed observation sheet was used collecting information every 2 h throughout the epidural treatment period in order to secure monitoring and adjustment of the treatment. Close contact was maintained with the wards.Results: We present a detailed analysis of our first 2000 postoperative patients, mainly after orthopaedic (46.1%), gastrointestinal (32.0%), urologic (8.7%) and vascular (8.5%) surgery. Duration of the treatment was less than 24 h in 41.4% and more than 48 h in 29.7%. Pain relief was adequate in most patients, best after vascular surgery in the lower extremities (mean VAS 0.15/10.0 (95% confidence interval 0.09–0.23)) and less after gastrointestinal (mean VAS 0.49/10 (0.43–0.54)) and thoracic surgery (mean VAS 0.59/10 (0.38–0.81)). The infusion was stopped due to respiratory depression in 3 patients (0.15%). Four (0.2%) had systolic blood pressure <80 mmHg and had to be treated with vasopressors. A total of 56 (2.8%) patients were considered to be problem patients due to excessive sedation (0.4%), hypotension (0.7%), respiratory depression (1.6%) or lower extremity paralysis (0.05%). All patients had urinary catheter until 6 h after termination of the epidural treatment. One patient had the epidural catheter accidentally placed subarachnoidally and experienced severe respiratory depression. No permanent sequelae were recorded in the postoperative patients, but 2 traumatised patients developed epidural abscesses after 3 weeks of treatment, which resulted in lower extremity paralysis. Late response to the warning signs might have contributed to the irreversible paraplegia.Conclusion: Our experience with this postoperative epidural analgesia regime is favourable. It has been easy to administer and monitor. Pain relief was excellent, side‐effects were few and picked up by the established routines followed by the ward staff except in the 2 trauma patients who developed epidural abscesses. The staff on the surgical wards were motivated for this kind of work. Education and strict surveillance routines are mandatory in order to secure prompt action when warning signs develops (e.g. lower limb paralysis).
Caudal clonidine and bupivacaine for combined epidural and general anaesthesia in children
Authors: MOTSCH J. , BÖTTIGER B. W. , BACH A. , BÖHRER H. , SKOBERNE Th. , MARTIN E. 
Published: January 2009

Background: Clonidine produces analgesia by actions on α2‐ad‐renoceptors and enhances both sensory and motor blockade from epidural injection of local anaesthetics. Low‐dose clonidine has been used so far for caudal injection in children. Our aim was to study the perioperative effects of high‐dose caudal clonidine when added to low concentration of bupivacaine for combined epidural and general anaesthesia in children.Methods: After induction of general anaesthesia caudal block was performed either with 1 ml kg‐1 bupivacaine 0.175% with the addition of clonidine 5 μg kg‐1 (n=20), or with 1 ml kg‐1bupivacaine 0.175% (n=20). The intraoperative anaesthetic requirements, the perioperative haemodynamic effects, respiratory rate, sedation score, postoperative pain scores and side effects were assessed by a blinded observer. A patient‐controlled analgesia system was used for postoperative pain relief. The quality of postoperative pain relief was assessed using Smiley's pain analogue scale.Results: Intraoperative haemodynamic responses did not differ between the groups. However, during emergence from general anaesthesia children in the clonidine group had significantly lower heart rates and blood pressures compared to children in the control group. In addition, heart rates and blood pressures were also lower in the clonidine group in the early postoperative period (P?< 0.05). Postoperative analgesia was significantly better in the clonidine group as evidenced by the total number of requests (3 vs 12, P< 0.05) and the total amount of tramadol (20.5 mg vs 72.8 mg, P < 0.05) administered. The duration of the caudal analgesia was significantly longer in the clonidine group (20.9±7.4 h vs 14.4±10.9 h, P< 0.05).Conclusion: Our results suggest that caudal clonidine 5 μg kg‐1 enhances and prolongs caudal blockade with bupivacaine 0.175% in children. It also blocks sympathoadrenergic responses during emergence from anaesthesia. Sedation and cardiovascular effects are observed up to 3 h into the postoperative period.