bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparative effects of xenon and nitrous oxide on diaphragmatic contractility in dogs
Authors: Hoshi T. , Fujii Y. , Toyooka H. 
Published: March 2003

Background:  Xenon at two different concentrations (30%, 60%) has no effect on diaphragmatic contractility. This study was undertaken to compare the effects of xenon and nitrous oxide (N2O), a commonly used and well‐established gas anesthetic, on diaphragmatic contractility in dogs.Methods:  Twenty‐one pentobarbitone‐anesthetized dogs were randomly divided into three groups of seven each: group 1 received xenon 30% (0.25 MAC) in oxygen; group 2 received N2O 47% (0.25 MAC) in oxygen; and group 3 received N2O 60% (0.32 MAC) in oxygen. Diaphragmatic contractility was assessed by transdiaphragmatic pressure (Pdi) at low‐ (20‐Hz) and high‐frequency (100‐Hz) stimulation, after maintaining 60 min of stable condition. The integrated electrical activity of diaphragm (Edi) to each stimulus was measured.Results:  With an inhalation of xenon 30%, N2O 47%, or N2O 60%, Pdi and Edi at both stimuli did not change. No difference in Pdi or Edi was observed among the groups.Conclusion:  When used at clinical concentration, xenon or N2O does not affect contractility and electrical activity of the diaphragm in dogs.
Intraocular pressure more reduced during anesthesia with propofol than with sevoflurane: both combined with remifentanil
Authors: Schäfer R. , Klett J. , Auffarth G. , Polarz H. , Völcker H. E. , Martin E. , Böttiger B. W. 
Published: March 2003

Background:  Short‐acting anesthetic agents are suitable and commonly used in ocular surgery. Propofol and remifentanil are known to reduce intraocular pressure (IOP), but no information is available regarding the effects of sevoflurane combined with remifentanil on IOP.Methods:  Therefore, a prospective, randomized study was conducted to compare the effects on IOP of two different anesthetic techniques: one based on a total intravenous anesthesia with propofol (Group P, bolus 1.5–2.0 mg/kg, maintenance 3.0–7.0 mg/kg/h); and the other based on sevoflurane (Group S, inhalational induction, end‐tidal concentration 0.7–1.2 vol.%). An infusion of remifentanil (10 µg/kg/h) was used with both techniques. In ASA I–III patients with normal IOP undergoing elective cataract surgery, using an applanation tonometer, IOP was measured contralateral to the operated eye at nine predefined time points before, during and after anesthesia.Results:  The two groups (n=20 each) were comparable with regard to demographic data and hemodynamic variables. Baseline IOP was 14.2±2.8 mmHg (Group P) and 14.1±2.4 mmHg (Group S; NS). During and following the induction of anesthesia, IOP was reduced in both groups. Intraocular pressure was significantly lower in Group P (6.0±3.2 mmHg) than in Group S (8.9±3.4 mmHg) during the induction of anesthesia.Conclusion:  In patients undergoing cataract surgery under general anesthesia with tracheal intubation, anesthetic regimens with propofol as well as with sevoflurane, both combined with remifentanil, decrease IOP significantly. The decrease in IOP was significantly more pronounced in the propofol group than in the sevoflurane group.
When is an anesthesiologist needed in a helicopter emergency medical service in northern Norway?
Authors: Nielsen E. W. , Ulvik A. , Carlsen A. W. , Rannestad B. 
Published: March 2003

Background: A national air ambulance service, including helicopters and airplanes, was implemented in Norway in 1988. The main intention was to offer advanced medical services when needed. All helicopters are manned by anesthesiologists. Catchment areas for the 11 helicopters span from cities to scarcely populated areas, particularly in the north. Our aim was to assess what proportion of ambulance missions carried out by the rescue helicopter in Bodø, northern Norway, delivered advanced medical treatment needing the skills of an anesthesiologist.Methods: Flight and ambulance records (n = 2078) from 1988 and 1990–98 (10 years) were analyzed retrospectively. Inter‐hospital transfers (n = 147) and search‐ and rescue missions (n = 332) were not included. According to the level of medical treatment given missions were categorized into three groups (A, B and C). Treatment in groups A and B would not require an anesthesiologist.Results: Two thousand and seventy‐eight ambulance missions carried 2166 patients (114 per 100 000 per year). Median take‐off and on‐scene times were 29 and 55 min, respectively. Seven hundred and fifty‐five patients (35%) suffered from cardiovascular disease, 495 (23%) were injured and 250 (12%) were parturients. One hundred and seven patients (5.0%) received advanced prehospital emergency treatment requiring an anesthesiologist. Forty‐five of the 107 patients survived to discharge from hospital, amongst whom 28 had received intravenous nitroglycerin for angina or suspected myocardial infarction.Conclusion: In our rural area, with a widely scattered population, 95% of patients received medical treatment not requiring an anesthesiologist. A selective use of the anesthesiologist seems indicated.
Patients' experiences with multiple stimulation axillary block for fast‐track ambulatory hand surgery
Authors: Koscielniak‐Nielsen Z. J. , Rotbøll‐Nielsen P. , Rassmussen H. 
Published: March 2003

Background: Ambulatory axillary block by multiple nerve stimulation (MNS) is effective and time efficient, but may be rejected by patients because of block pain. This prospective study assessed patients' anxiety and acceptance of this block, identified which of the components of blocking procedure is most painful (i.v. line insertion, repeated needle passes, local anesthetic injection, or electrical stimulation) and recorded patients' anesthetic preferences for the future hand surgery.Methods: Upon arrival at the day unit, 100 unpremedicated adult patients without previous experience of peripheral nerve stimulation indicated on the visual analog scale (VAS; 0–100) their anxiety about the block. The blocking procedure was then explained step‐by‐step. After inserting the i.v. line and freezing the skin in axilla, four terminal nerves (musculocutaneous, median, ulnar, radial) were electrolocated using an initial current of 2 mA and a target current of 0.1–0.5 mA. Pain caused by the individual components of blocking procedure was assessed on VAS before the start of surgery. On the day after the operation, the patients reassessed their anxiety for the next axillary block and indicated which anesthetic method (block alone, block plus sedation, or general anesthesia) they would prefer for the future hand surgery.Results: Before the block, 59 patients admitted being anxious about regional block (median anxiety VAS=27), compared with 42 patients (anxiety VAS=10) postoperatively: P<0.01. Median intensity of electrical stimulation pain was significantly higher (VAS=16) than pain of local anesthetic injections (VAS=8), i.v. line insertion (VAS=6) and multiple needle passes (VAS=5). However, only 53 patients categorized electrolocation as painful. Twenty‐seven reported discomfort but not pain, and 20 patients described the sensation as ‘funny’ or ‘strange’. None of the patients had surgical pain during operation. Mean duration of surgery was 77 min, and of hospital stay 166 min. Ninety‐eight patients would choose the same block for the future hand surgery, 13 of which would like sedation before the block, and two patients did not wish to be awake during any surgery. Ninety‐five patients were satisfied with fast‐tracking.Conclusions: Fear of block pain is diminished after experiencing the blocking procedure. Electrical stimuli was perceived as painful by 53% of patients, and this pain was more intense than with other block components. The majority of our patients would choose axillary block without sedation for future hand surgery and are satisfied with fast‐tracking.
Survey of epidural analgesia management in general intensive care units in England
Authors: Low J. H. S. 
Published: March 2003

Background: The management of epidural analgesia is controversial. Many intensive care unit (ICU) patients may benefit from this form of analgesia but have one or more contraindications to its use. Sepsis, coagulopathy, insertion in a sedated, ventilated patient, and lack of consent are common problems in ICU patients. Little has been published to help guide practice in this area. I wished to establish the current practice of the management of epidural analgesia in general ICUs in England when relative or absolute contraindications occur, in order to determine the current standard of care for placement and use of epidural analgesia in ICU patients.Methods: A postal questionnaire survey of the management of epidural analgesia in critically ill patients was sent to the named clinical director of all (216) general ICUs in England.Results: Responses were received from 159 (75%) units: 89% of responding units use epidural analgesia but only 51(32%) have a written policy covering its use. Anesthetists or intensivists with an anesthetic background sited all epidural catheters; 68% of units would not site an epidural in a patient with positive blood cultures; but only 52% considered culture negative sepsis (systemic signs of sepsis with no organism isolated) to be a contraindication. Neither lack of consent nor the need for anticoagulation after the catheter had been sited were considered contraindications to inserting an epidural catheter by the majority of respondents. Although 71% of the units would remove an epidural catheter if a patient developed positive blood cultures after it had been sited, the majority of the ICUs did not consider culture negative sepsis and the need for anticoagulation contraindications to maintain a previously sited epidural.Conclusions: Practice varied considerably with little consensus. Although all the respondents use epidural analgesia in critically ill patients, the indications and contraindications to epidural analgesia remain controversial, and further research is required to help define the role of epidural analgesia in this high‐risk group.
Effect of axillary brachial plexus blockade on baroreflex‐induced skin vasomotor responses: assessing the effectiveness of sympathetic blockade
Authors: Szili‐Torok T. , Paprika D. , Peto Z. , Babik B. , Bari F. , Barzo P. , Rudas L. 
Published: March 2003

Background: The combination of laser Doppler flowmetry and non‐invasive blood pressure monitoring allows the continuous observation of cutaneous vascular resistance (CVR). Continuous recording of unmodulated skin blood flow (SBF) is very sensitive to artefacts, rendering the method unreliable. In contrast, intermittent short lasting challenges of the CVR by cardiovascular autonomic reflexes may provide information about the responsiveness of the sympathetic nervous system in the skin.Methods: Eleven patients with below‐wrist hand surgery (six males and five females; aged 35.2±7.1 years) performed Valsalva maneuver following axillary blockade. Skin blood flow was continuously monitored on the forearm of the side axillary blockade, as well as on the contra‐lateral forearm, which was used as the control. The responses were expressed as changes compared with the baseline level derived from a resting period of 30 s. The maximal change in CVR was determined during the late strain phase of the Valsalva maneuver on both sides. For numerical comparison the change in CVR on the axillary blockade and control sides were simultaneously calculated.Results: During the Valsalva maneuver a significant increase in CVR was observed on the control side with a maximum value during the late strain phase (baseline 0.18±0.1 and late strain phase 0.42±0.2 relative units; P<0.01). In contrast, only minimal changes were detected on the side of axillary blockade in CVR (baseline 0.17±0.8 and late strain 0.16±0.2 relative units; P=NS).Conclusions: Our findings support the disputed hypothesis that the human skin microvasculature is involved in baroreflex regulation under thermoneutral conditions. The determination of baroreflex stimulus‐induced microvascular responses may serve as a feasible method for monitoring the effectiveness of sympathetic blockade.
No enhancement of sensory and motor blockade by ketamine added to ropivacaine interscalene brachial plexus blockade
Authors: Lee Il‐Ok , Kim Woo‐Kyung , Kong Myung‐Hoon , Lee Mi‐Kyung , Kim Nan‐Sook , Choi Young‐Seok , Lim Sang‐Ho 
Published: March 2003

Background: Ketamine can enhance anesthetic and analgesic actions of a local anesthetic via a peripheral mechanism. The authors' goal was to determine whether or not ketamine added to ropivacaine in interscalene brachial plexus blockade prolongs postoperative analgesia. In addition, we wanted to determine the incidence of adverse‐effects in patients undergoing hand surgery.Methods: Sixty adults scheduled for forearm or hand surgery under the interscalene brachial plexus block were prospectively randomized to receive one of the solutions of the study. Group P received 0.5% ropivacaine 30 ml, group K received 0.5% ropivacaine 30 ml with 30 mg ketamine, and group C received 0.5% ropivacaine with 30 mg ketamine i.v. Loss of shoulder abduction, elbow flexion, wrist flexion and loss of pinprick in the C4–7 sensory dermatomes were assessed at 1‐min intervals. Adverse‐effects were assessed every 5 min. The duration of the sensory and motor blocks was assessed after operation. Adverse‐effects were also recorded.Results: The onset time of sensory or motor blockade and the duration of sensory or motor blockade were similar in all groups. Adverse‐effects occurred in 44% of patients in group K and 94% of group C.Conclusion: This study suggests that 30 mg ketamine added to ropivacaine in the brachial plexus block does not improve the onset or duration of sensory block, but it does cause a relatively high incidence of adverse‐effects. These two findings do not encourage the use of ketamine with local anesthetics for brachial plexus blockade.
Nasal CPAP therapy: effects of different CPAP levels on pressure transmission into the trachea and pulmonary oxygen transfer
Authors: Kindgen‐Milles D. , Buhl R. , Loer S. A. , Müller E. 
Published: March 2003

Background: Nasal continuous positive airway pressure (nCPAP) is considered useful for prophylaxis and treatment of respiratory complications following major thoracic surgery. It is unknown, however, which CPAP levels are required to avoid alveolar derecruitment and to consistently improve pulmonary oxygen transfer in patients following thoracotomy. We therefore studied the effects of different nCPAP levels on pressure transmission into the trachea as well as on pulmonary oxygen transfer.Methods:   In 10 consecutive patients after cardiac or thoracic vascular surgery, following extubation in the ICU, nCPAP was generated by means of a high‐flow gas source and applied randomly at levels of 5 or 10 cm H2O. Airway pressure was recorded continuously in the nasal mask and the trachea. The PaO2/FiO2ratio was calculated from the tracheal oxygen concentration, and PaO2 was determined while breathing at an ambient and elevated airway pressure. Haemodynamic variables (heart rate, arterial blood pressure, central venous pressure) were also recorded.Results:   Mean pressures in the nasal mask were 5.4±0.1 and 9.7±0.3 cm H2O. Corresponding tracheal pressures were 2.8±1.0 vs. 7.2±1.1 cm H2O (P=0.007). With higher mask pressure, the fraction of pressure transferred from the nasal mask into the trachea was larger (0.75±0.03 vs. 0.52±0.05; P=0.04), and tracheal pressures remained positive during the entire respiratory cycle in all patients. In contrast, with 5.4 cm H20, negative pressure changes during inspiration occurred in five out of 10 patients. The PaO2/FiO2 ratio increased from 183±53 (ambient pressure) to 199±74 (nCPAP 5.4 cm H2O; P=0.25) and to 333±54 (nCPAP 9.7 cm H2O; P=0.003). Nasal CPAP did not alter hemodynamics.Conclusion: Nasal CPAP is an effective non‐invasive means of increasing tracheal and thus intrathoracic pressure without adverse hemodynamic effects. Only mask pressures of 9–10 cm H2O were sufficient to consistently improve pulmonary oxygen transfer in patients following thoracotomy.
Volume‐targeted therapy of increased intracranial pressure: the Lund concept unifies surgical and non‐surgical treatments
Authors: Grände P.‐O. , Asgeirsson B. , Nordström C.‐H. 
Published: March 2003

Opinions differ widely on the various treatment protocols for sustained increase in intracranial pressure (ICP). This review focuses on the physiological volume regulation of the intracranial compartments. Based on these mechanisms we describe a protocol called ‘volume‐targeted’ (‘Lund concept’) for treatment of increased ICP.The driving force for transcapillary fluid exchange is determined by the balance between effective transcapillary hydrostatic and osmotic pressures. Fluid exchange across the intact blood–brain barrier (BBB) is counteracted by the low permeability to crystalloids (mainly Na+ and Cl–) combined with the high osmotic pressure (5500 mmHg) on both sides of the BBB. This contrasts to most other capillary regions where the osmotic pressure is mainly derived from the plasma proteins (approximately 25 mmHg). Accordingly, the level of the cerebral perfusion pressure (CPP) is of less importance under physiological conditions. In addition cerebral intracapillary hydrostatic pressure (and cerebral blood flow) is physiologically tightly autoregulated, and variations in systemic blood pressure are generally not transmitted to these capillaries.If the BBB is disrupted, transcapillary water transport will be determined by the differences in hydrostatic and colloid osmotic pressure between the intra‐ and extracapillary compartments. Under these pathological conditions, pressure autoregulation of cerebral blood flow is likely to be impaired and intracapillary hydrostatic pressure will depend on variations in systemic blood pressure.The volume‐targeted ‘Lund concept’ can be summarized under four headings: (1) Reduction of stress response and cerebral energy metabolism; (2) reduction of capillary hydrostatic pressure; (3) maintenance of colloid osmotic pressure and control of fluid balance; and (4) reduction of cerebral blood volume. The efficacy of the protocol has been evaluated in experimental and clinical studies regarding the physiological and biochemical (utilizing intracerebral microdialysis) effects, and the clinical experiences have been favorable.
Immune response in asymptomatic smokers
Authors: Zeidel A. , Beilin B. , Yardeni I. , Mayburd E. , Smirnov G. , Bessler H. 
Published: March 2003

Background:  It has been demonstrated that cigarette smoking affects the immune system. Impairment of alveolar mononuclear cell function, described previously, may contribute to the higher rate of postoperative respiratory infections. However, increased susceptibility of smokers to infections of other origin (e.g. wound‐related) implies that tobacco effect is not restricted to the respiratory immune competent cells. The present study was designed to investigate the systemic effect of tobacco smoking as it exerted on blood‐derived immune cells. We measured systemic cytotoxic activity of natural killer cells, production of pro‐ and anti‐inflammatory cytokines by blood mononuclear cells and their proliferation in response to mitogens. To minimize the immunosuppressive effect of other smoke‐related factors, the smokers with chronic obstructive pulmonary disease (COPD) were excluded from this study.Methods:  Peripheral blood mononuclear cells (PBMC) from 24 chronic asymptomatic smokers, and 28 controls, age and gender matched, were isolated and incubated in vitro with lipopolysaccharide (LPS) or phytohemagglutinin (PHA) to induce secretion of IL‐1β, IL‐1ra, IL‐6, IL‐10, TNFα and IL‐2, respectively, from mononuclear cells. The level of the cytokines in the supernatants was measured using ELISA kits. The proliferative response to the mitogens PHA and concanavalin A (ConA) was evaluated by 3H‐thymidine incorporation and NK cell cytotoxicity by 51Cr release assay.Results: Mononuclear cells from smokers showed increased production of the pro‐inflammatory cytokines IL‐1β, IL‐6 and TNFα and enhanced proliferative response to mitogens as compared to non‐smoking population.The secretion of IL‐2 and the anti‐inflammatory cytokines IL‐1ra and IL‐10 was similar in both groups. NK cell cytotoxic activity was suppressed in the smokers.Conclusion: Cigarette smokers without chronic obstructive pulmonary disease (COPD) exhibit impaired NK cytotoxic activity in peripheral blood and unbalanced systemic production of pro‐ and anti‐inflammatory cytokines. These changes may serve as predisposing factors for respiratory and systemic infections in the postoperative period and should alert an anesthetist during perioperative management.
Extubation after breathing trials with automatic tube compensation, T‐tube, or pressure support ventilation
Authors: Haberthür C. , Mols G. , Elsasser S. , Bingisser R. , Stocker R. , Guttmann J. 
Published: March 2003

Background: Automatic tube compensation (ATC) is a new option to compensate for the pressure drop across the endotracheal or tracheostomy tube (ETT), especially during ventilator‐assisted spontaneous breathing. While several benefits of this mode have so far been documented, ATC has not yet been used to predict whether the ETT could be safely removed at the end of weaning, from mechanical ventilation.Methods: We undertook a systematic trial using a randomized block design. During a 2‐year period, all eligible patients of a medical intensive care unit were treated with ATC, conventional pressure support ventilation (PSV, 5 cmH2O), or T‐tube for 2‐h. Tolerance of the breathing trial served as a basis for the decision to remove the endotracheal tube. Extubation failure was considered if reintubation was necessary or if the patient required non‐invasive ventilatory assistance (both within 48 h).Results and conclusions: After the inclusion of 90 patients (30 per group) we did not observe significant differences between the modes. Twelve patients failed the initial weaning trial. However, half of the patients who appeared to fail the spontaneous breathing trial on the T‐tube, PSV, or both, were successfully extubated after a succeeding trial with ATC. Extubation was thus withheld from four and three of these patients while breathing with PSV or the T‐tube, respectively, but to any patient breathing with ATC. It seems that ATC can be used as an alternative mode during the final phase of weaning from mechanical ventilation. Furthermore, this study may promote a larger multicenter trial on weaning with ATC compared with standard modes.