bluuebunny/crossref_metadata_2025 huggingface dataset:
How do anaesthesiologists treat malignant hyperthermia in a full‐scale anaesthesia simulator?
Authors: Gardi T. i , Christensen U. C. , Jacobsen J. , Jensen P. F. , Ørding H.
Published: March 2003

Background: Clinical malignant hyperthermia (MH) is rare and usually occurs unexpectedly. Prompt diagnosis and correct treatment is crucial for survival of the patient developing fulminant MH. The aims of the present study were to investigate whether anaesthesiologists could make a correct diagnosis of MH and to evaluate their treatment of fulminant MH in a simulator.

Methods: Thirty‐two teams (one anaesthesiologist/one nurse anaesthetist) were exposed to an event of clinical MH in a full‐scale simulator. Their performance was videotaped for retrospective analysis of the treatment on the basis of the recommendations of the Danish Malignant Hyperthermia Register.

Results: All 32 teams asked the surgeon to terminate the surgery as fast as possible, switched off the vaporiser and administered 100% oxygen. Although all intended to hyperventilate the patient, only 14 teams actually managed to perform the hyperventilation. Most problems were found in teams that switched to manual ventilation. All teams treated the patient with dantrolene, and symptomatic treatment was initiated by all even though some elements of the full treatment were lacking, possibly due to the limited time available.

Conclusion: All teams diagnosed MH in the simulator satisfactorily. The surprising negative finding was that more than half of the participants failed to hyperventilate the “patient” although they intended to do so. This investigation shows that the problem in these teams’ treatment of MH was more a question of practical management of the resources than lack of theoretical knowledge.
Probability of acceptable intubation conditions with low dose rocuronium during light sevoflurane anaesthesia in children
Authors: Eikermann M. , Renzing‐Köhler K. , Peters J.
Published: March 2003

Background: To define the rocuronium doses which would provide 50%, 90%, and 95% probability of ‘acceptable’ intubation conditions during light sevoflurane anaesthesia, we studied 60 children aged 2–7 years in a prospective, randomised, assessor blinded study.

Methods: After mask ventilation with 1 MAC sevoflurane/N2O for 17±1 (x̌±SD) min we administered rocuronium (either 0.15, 0.22, 0.3, 0.5, or 1.0 mg  ·  kg−1) or placebo, and quantified the evoked force of the adductor pollicis muscle. Intubation conditions were assessed before and 2 min after injection of the test drug.

Results: Intubation conditions were improved significantly with rocuronium and scored ‘acceptable’ in 70%, 90%, and 100% of the children after injection of rocuronium 0.15, 0.22, and 0.3 mg  ·  kg−1, respectively. In parallel, twitch tension decreased to 53% (6–100), 26% (11–100), and 11% (0–19) of baseline (median (range)). Recovery of train‐of‐four ratio to 0.8 was achieved 13 (7–19), 16 (8–28), and 27 (23–44) min after injection of the respective rocuronium doses. Higher rocuronium doses did not further improve intubation conditions but only prolonged time of neuromuscular recovery. Logistic regression analysis revealed that rocuronium 0.11 (CI 0.05–0.16), 0.21 (0.14–0.28), and 0.25 (0.15–0.34) mg  ·  kg−1 provides a 50%, 90%, and 95% probability of ‘acceptable’ intubation conditions in children during 1 MAC sevoflurane/N2O anaesthesia, respectively. Furthermore, we calculated that force depression of adductor pollicis muscle to 81% (CI 72–90), 58% (42–74), and 50% (29–71) of baseline is associated with 50%, 90%, and 95% probability of ‘acceptable’ intubation conditions.

Conclusions: Submaximal depression of muscle force with low dose rocuronium improves intubation conditions in children during light sevoflurane anaesthesia while allowing rapid recovery of neuromuscular function. However, when using low dose rocuronium neuromuscular monitoring may be helpful to detect children with inadequate response to the relaxant so as to avoid an unsuccessful intubation attempt.
Bilateral eye hemorrhage after laparoscopic cholecystectomy
Authors: Calenda E. , Muraine M. , Zerzour H. , Sambo B. , Siahmed K.
Published: March 2003

A case of bilateral eye hemorrhage after laparoscopic cholecystectomy, probably caused by an increase in venous blood pressure due to carbon dioxide insufflation, is reported.
Outcome assessment in chronic non‐cancer pain treatment
Authors: Williams A. C. De C.
Published: March 2003

Increased literacy of the pain research community concerning the formal requirements of assessment instruments – reliability, validity and sensitivity to change – means that assessment can now be addressed with reference to underlying dilemmas both about techniques of measurement and its targets. This commentary on outcome assessment is intended to facilitate the choice of measures, from an imperfect field, by raising some of those problems. It deals first with summary measures, and then with the separate domains of pain experience, affect, cognition and coping, behavior and activity, social role interference, biological and fitness measures, and use of health care, addressing in particular the conceptual basis of each.
Pain in cancer and chronic non‐cancer conditions: similarities and differences
Authors: Fordyce W.
Published: March 2003

A conceptual model within which to view and compare cancer and chronic non‐cancer pain is provided. Studies comparing the two are reviewed. Implications for deploying management and intervention strategies are then analyzed in terms of disease, cognitive‐behavioral and social‐contextual considerations.
Iatrogenic painful neuropathic complications of surgery in cancer
Authors: Marchettini P. , Formaglio F. , Lacerenza M.
Published: March 2003

It is estimated that at least one out of four patients with cancer complains of pain originating from nerve injury. Nerve injury may result from direct invasion/compression by tumour, or by remote effect of the cancer such as paraneoplastic polyneuropathy. In many cases, the nerve injury is caused by medical therapy, or surgical interventions. Pain generated by drugs or medical acts is called iatrogenic. A common iatrogenic neuralgia is chemotherapy induced painful polyneuropathy. This neuropathy typically affects mostly the small myelinated and unmyelinated nerve fibres. Surgical and anaesthesiological interventions also frequently cause direct nerve stretch or section. Some interventions, particularly those requiring extended resection, have a higher incidence of painful sequelae. Limb and colon amputation, nerve dissection, mastectomy and thoracotomy are the most common interventions for cancer known to cause nerve injury. As pain clinicians, we focus attention on the painful consequences of surgical interventions because there is evidence that a more accurate surgical approach and possibly a prophylactic prevention of the neuralgia may reduce the painful sequelae of nerve injury.
Somatization and chronic pain
Authors: Birket‐Smith M.
Published: March 2003

The experience of pain is related not only to tissue damage and physical illness, but also to mental phenomena including depression, anxiety and somatization. Somatization is common among chronic pain patients and presents special problems in management and treatment. Somatoform patients are often given inappropriate diagnoses, treated for non‐existent depressive disorders, and exposed to multiple, superfluous investigations. Psychological models of chronic pain and somatization are presented, and treatment issues including psychotherapy and the use of antidepressants are discussed.
Neuropathic pain: what do we do with all these theories?
Authors: Devor M.
Published: March 2003

Only a generation ago there were few ideas as to what might cause neuropathic pain, and even fewer relevant data. In contrast, we can currently point to hundreds of distinct cellular changes that are triggered by nerve injury and that might be relevant to the emergence of pain symptomatology. The number may soon increase to thousands. It is essential, therefore, to redirect efforts towards the development of experimental strategies for testing which of these are essential parts of the pain process and which are tangential. In this paper I point out four such strategies: timing, deletion, prevention and genetic heterogeneity, and summarize how one neuropathic pain theory, the ectopic pacemaker hypothesis, holds up to scrutiny.
Effect of expiratory resistance on gas‐exchange and breathing pattern in chronic obstructive pulmonary disease (COPD) patients being weaned from the ventilator
Authors: Lourens M. S. , Berg B. Van Den , Hoogsteden H. C. , Bogaard J. M.
Published: March 2003

Background: The majority of patients with severe chronic obstructive pulmonary disease (COPD) have flow limitation, which has deleterious side effects. If these patients are mechanically ventilated, this often results in difficult weaning. Spontaneously breathing COPD patients experience a beneficial effect of pursed lip breathing. We investigated whether in intubated COPD patients application of an external resistance could produce the same beneficial effects on breathing pattern and gas‐exchange as pursed lip breathing.

Methods: Ten COPD patients with flow limitation were studied during pressure support mechanical ventilation. Two types of expiratory resistances were applied: one fixed level of resistance and one with a resistive pressure decay. Each resistance was applied in 5 patients and the highest level was chosen that did not cause hyperinflation. Blood gas values and breathing pattern with and without resistance were compared.

Results: With resistance 1, gas‐exchange and breathing pattern did not change significantly; average PCO2 changed from 8.0 to 8.1 kPa, PO2 from 10.2 to 10.3 kPa, tidal volume from 0.380 to 0.420 l, respiratory rate from 25 to 23 bpm and inspiratory:expiratory ratio from 1:1.9 to 1:2.0. With resistance 2, gas‐exchange and breathing pattern did not change significantly; average PCO2 changed from 5.8 to 6.0 kPa, PO2 from 11.1 to 12.1 kPa, tidal volume from 0.733 to 0.695 l, respiratory rate from 16 to 18 bpm and inspiratory:expiratory ratio from 1:2.3 to 1:2.9.

Conclusion: In intubated COPD patients being weaned from the ventilator, application of an external resistance did not have the same beneficial effects as pursed lip breathing.
Hemodynamic and sympathetic effects of fenoldopam and sodium nitroprusside
Authors: Yakazu Y. , Iwasawa K. , Narita H. , Kindscher J. D. , Benson K. T. , Goto H.
Published: March 2003

Background: Fenoldopam is a novel dopamine‐1 receptor selective agonist that can be used as a vasodilator perioperatively to treat hypertension and to produce induced hypotension. We were interested to find out whether there were any differences between fenoldopam (FM) and sodium nitroprusside (SNP), one of the most popular vasodilators, in their effects on hemodynamics and sympathetic outflow using not only neuraxis intact but also baro‐denervated animal models.

Methods: A total of 60 New Zealand white rabbits were divided into two groups of 30 each: the neuraxis‐intact group and the totally baro‐denervated group. Each group was further divided into three groups of 10 each to receive SNP 10 μg · kg−1, FM 10 μg · kg−1 or FM 20 μg · kg−1, respectively. Mean arterial pressure (MAP), heart rate (HR) and renal sympathetic nerve activity (RSNA) were recorded before and after intravenous (i.v.) administration of each agent. In addition, cardiac and sympathetic baroreflex sensitivity were assessed in the neuraxis‐intact animals.

Results: In the neuraxis‐intact groups, although RSNA was increased to a similar extent in all three groups (P<0.01), the reduction of MAP with FM groups was significantly greater than with SNP (P<0.05). HR was increased only in the SNP group. Cardiac (HR) and sympathetic barosensitivity were significantly attenuated with FM 20 μg · kg−1 as compared to the SNP group. In the baro‐denervated groups, there were significant and similar degrees of reduction of MAP in all three group up to 1 min (P<0.01). MAP remained significantly decreased in the FM groups for 10 min (only 2 min with SNP) in both animal models.

Conclusions: Unlike sodium nitroprusside, fenoldopam attenuates both cardiac (heart rate) and sympathetic baroreflex sensitivity, which may explain the lack of rebound hypertension with fenoldopam. The offset of hypotensive effects of fenoldopam is a significantly slower process as compared to nitroprusside, and this may be an unfavorable feature of fenoldopam should overshoot of hypotension occur.
Danish Anaesthesia Allergy Centre – preliminary results
Authors: Garvey L. H. , Roed‐Petersen J. , Menné T. , Husum B.
Published: March 2003

Background: Anaphylactoid reactions in anaesthesia are rare and should ideally be investigated in specialist centres. At Gentofte University Hospital, we established such a centre in 1998 as a joint venture between the Departments of Anaesthesiology and Dermatology. We present the methodology, diagnostic algorithm and preliminary results from our centre.

Methods: We are open for referral of patients from all of Denmark. Reactions are classified using a three‐grade severity scale and all reactions ranging from mild to severe are investigated. Investigations follow a standard step‐by‐step protocol of in vitro testing and skin testing. Blood samples for tryptase analysis are taken at the time of reaction and a control sample is taken together with samples for specific IgE analysis 2–4 weeks after the reaction. Subsequent skin testing comprises both prick tests and intradermal tests in most cases. Patients are tested with all substances they were exposed to, including antibiotics, colloids, latex and chlorhexidine.

Results: A total of 68 patients have been referred to date (July 2001) and 36 have completed investigations. Positive test results were mainly seen in patients with more severe reactions, and there were more men than women in the group with the most severe reactions. Six patients had positive specific IgE, three for penicillin, two for latex and one for thiopental. In all, 21 patients had positive skin tests to various substances, of whom four men with anaphylactic shock tested positive for chlorhexidine. Only one patient has tested positive to a neuromuscular blocking drug (NMBD) so far.

Discussion:

Our preliminary results appear to differ in two ways from results usually found in this field. Firstly, only one patient has tested positive for a NMBD and secondly, we have had four patients with anaphylactic shock who have tested positive for chlorhexidine. Possible reasons for these differences are discussed.
Practice and knowledge of cricoid pressure in southern Sweden
Authors: Schmidt A. , Åkeson J.
Published: March 2003

Background: For 40 years cricoid pressure has been used to prevent regurgitation of gastric contents during induction of anaesthesia. Recent studies have emphasised use of more moderate force so as not to deteriorate ventilation or endotracheal intubation. This study was undertaken to assess the current practice and knowledge of cricoid pressure among anaesthesia personnel in southern Sweden.

Methods: Forty‐eight subjects at two anaesthetic departments in southern Sweden were asked to apply and maintain cricoid pressure for 60 s with their dominant and non‐dominant hands, respectively, in a laryngotracheal model during simulated intravenous induction of anaesthesia. Where and how pressure was applied as well as the force used by each subject was recorded together with information on individual experience and knowledge of the technique.

Results: There were no significant changes in force applied over time, and no significant differences in force between dominant (median 36 N; 25th percentile 26 N; 75th percentile 50 N) and non‐dominant (37; 26; 50 N) hand, between female and male subjects or between physicians, nurses and assistant nurses. Force exceeding 60 N was recorded at least once in 21% of subjects. More than two‐thirds (69%) had not heard of any recommended level of force to be applied. Forty percent of anaesthesiologists were unaware of any contraindications.

Conclusion: More specific education and training seems mandatory to improve clinical use of cricoid pressure and possibly increase patient safety. Simulators allowing cricoid pressure to be carried out and evaluated in a standardised manner should therefore be incorporated into future training programmes and airway management courses.
Reorganization of actin in neurons after propofol exposure
Authors: Oscarsson A. , Massoumi R. , Sjölander A. , Eintrei C.
Published: March 2003

Background: It has previously been shown that propofol in clinically relevant concentrations induces a calcium‐dependent conformational change in the cytoskeleton. The aim of this study was to further clarify the effect of propofol on the actin cytoskeleton and to determine if this conformational change is mediated by the interaction between the GABAA‐receptor and propofol.

Methods: Primary cultured cortical neurons from newborn rats were treated with propofol 3 μg · ml−1 in a time‐response titration, with and without preincubation with the GABAA‐receptor antagonist, bicuculline. Actin‐protein content was detected by Western blot analysis and the cellular content of F‐actin measured by a spectrophotometric technique.

Results: Propofol triggers a relatively slow statistically significant increase in the intracellular F‐actin content, maximum after 20‐min incubation (160%±16.3) (mean±SEM) P<0.05. The propofol‐induced increase in F‐actin was effectively blocked by bicuculline. The increase in intracellular actin content after exposure to propofol as well as the effect of bicuculline were verified by Western blot analysis.

Conclusion: The present study shows that propofol triggers a time‐dependent change of actin. Since this reorganization can be blocked effectively by a GABAA‐receptor antagonist, this suggests that the GABAA‐receptor is involved in the pathway leading to cytoskeletal reorganization after propofol treatment. The actin polymerization reached its maximum after 20 min. Therefore, we believe that the propofol‐induced changes might be connected with slower cellular responses such as cell‐to‐cell interaction and/or channel regulation.
The effects of propofol or halothane on free radical production after tourniquet induced ischaemia‐reperfusion injury during knee arthroplasty
Authors: Aldemir O. , Celebi H. , Cevik C. , Duzgun E.
Published: March 2003

Background: Ischaemia‐reperfusion injury following tourniquet release is a good in vivo model for evaluating acute conditions. The aim of the study was to investigate the effects of propofol or halothane anaesthesia on oxidative stress by determining malondialdehyde (MDA) levels during knee arthroplasty.

Methods: Thirty patients undergoing orthopaedic surgery were divided into two groups. Anaesthesia was induced with either fentanyl 100 μg and propofol 2 mg kg−1 (Group 1) or fentanyl 100 μg and thiopentone 5 mg kg−1 (Group 2) and maintained with infusion of propofol in Group 1 or inhalation of halothane in Group 2. ECG, SpO2, EtCO2, and mean arterial pressure (MAP) were monitored. Venous and arterial blood samples were obtained at different measurement times for MDA and blood gas analyses.

Results: There was a significant decrease in MAP in the 1st and 5th minutes after tourniquet release (ATR) when compared with the 5th minute before tourniquet release (BTR) in both groups. Heart rate (HR) increased significantly in the 1st minute ATR in Group 1 only. EtCO2 increased significantly in the 1st and 5th minutes ATR, SpO2 decreased in the 1st minute ATR in both groups. There was a significant decrease in pH and increase in pCO2 at 1, 5 and 30 min ATR in both groups. pO2 values decreased in the 1st minute ATR in Group 1 only and returned to control values at 5 min ATR and decreased at 30 min ATR in the recovery room in both groups. The differences in SaO2 were similar to SpO2. MDA levels decreased before and after release of tourniquet when compared to baseline in both groups. However, there was a statistically significant decrease only in Group 1.

Conclusion: Propofol may be a good choice of anaesthetic when an ischaemia‐reperfusion injury is anticipated as in orthopaedic surgery requiring a tourniquet, due to its antioxidant properties, but halothane needs further study.
Effects of sustained pressure application on compliance and blood gases in healthy porcine lungs
Authors: Markström A. , Hedlund A. , Sjöstrand U. , Nordgren A. , Lichtwarck‐Aschoff M.
Published: March 2003

Background: Short periods of sustained increase in airway pressures (Pressup) are believed to re‐open lung areas that collapsed upon induction of anaesthesia. Recruitment of alveolar surface is usually assessed in terms of changes in the pressure–volume (PV) curve. The purpose of this study was to analyse PV‐curves before and after a Pressup and to ascertain whether such changes are compatible with the concept of recruitment of lung volume.

Methods: During ketamine anaesthesia, 12 healthy piglets were subjected to a Pressup with end‐expiratory pressure (PEEP) of 12 cmH2O and end‐inspiratory pressure of 40 cmH2O. Before and after Pressup, PV‐curves were obtained from a slow insufflation of 630 ml at zero PEEP (ZEEP).

Results: Compliance was non‐linear both before and after Pressup increasing up to 300 ml and sharply decreasing thereafter. After Pressup, the entire compliance curve was shifted to a higher absolute level. Up to 100 ml and a pressure level corresponding to the lower inflection point on the PV‐curve (LIP), compliance was higher before Pressup. No effects on blood gases could be observed.

Conclusion: If the similar shape of the compliance curve corresponds to a similar chain of re‐opening and overdistension events, this would imply that all volume gained by Pressup is lost within 10 min, without explaining the higher absolute compliance following Pressup. We speculate that a) re‐opening of rapidly collapsing small airways determines the initial compliance increase; b) the lower compliance after Pressup until LIP indicates reduced intratidal re‐opening of lung regions; and c) changes in bronchomotor tone induced by Pressup raise the absolute compliance, with a similar scenario of alveolar and small airway recruitment now taking place but at different degrees of airway stiffness.
Effects of the endothelin receptor antagonist bosentan on cardiac performance during porcine endotoxin shock
Authors: Wanecek M. , Weitzberg E. , Alving K. , Rudehill A. , Oldner A.
Published: March 2003

Background: Cardiac dysfunction during septic shock is well described but the underlying mechanisms still remain to be resolved. This study was conducted to elucidate the involvement of endothelin in cardiac function during endotoxin shock by the use of endothelin receptor antagonism.

Methods: Anaesthetised and haemodynamically stable landrace pigs received the nonpeptide mixed endothelin receptor antagonist bosentan, two hours after onset of endotoxaemia (n=7). Cardiopulmonary vascular changes, including cardiac index, stroke work index, coronary artery blood flow, rate of change of left ventricular pressure (dp/dt), and arterial and coronary sinus plasma levels of endothelin‐1‐like immunoreactivity were compared to a control group only receiving endotoxin (n=7).

Results: Plasma endothelin‐1‐like immunoreactivity increased threefold in the control group. Bosentan effectively counteracted the endotoxin induced decrease in cardiac index. This was accompanied by a significant reduction of both right and left ventricular afterload. In addition, coronary artery blood flow increased and coronary vascular resistance decreased compared to controls. Dp/dt remained unaffected by endothelin receptor antagonism. A further increase in plasma endothelin‐1‐like immunoreactivity was seen in response to bosentan.

Conclusion: These results indicate that the increased endothelin production during endotoxaemia contributes to a depressed cardiac performance and that endothelin receptor antagonism may counteract this development. Possible mechanisms for the improved cardiac performance include both a reduction of afterload and enhanced coronary blood flow.
Effect of intravenous prostaglandin E1 on pial vessel diameters and intracranial pressure in rabbits
Authors: Miyabe M. , Fukuda T. , Saito S. , Tajima K. , Toyooka H.
Published: March 2003

Background: The main advantages of prostaglandin E1 (PGE1) for induced hypotension during neurosurgery include a rapid onset of action, a quick recovery from hypotension, lack of toxicity, maintenance of adequate perfusion to vital organs, and maintenance of cerebral blood flow reactivity to carbon dioxide during hypotension. However, there is no report that shows the effect of PGE1 on cerebral microvessel diameter and only a few data are available that show the effect of PGE1 on intracranial pressure. The aim of this study was to measure cerebral arteriole and venule diameters and intracranial pressure (ICP) during PGE1‐induced hypotension to evaluate whether PGE1 is suitable for neuroanesthesia.

Methods: We measured the effects of 0.1, 0.3, 1.0, 3.0, and 10.0 μg  ·  kg−1  ·  min−1 of intravenous PGE1 on mean arterial pressure (MAP), cerebral arteriole and venule diameters and ICP in anesthetized rabbits.

Results: MAP decreased statistically significantly from baseline at the infusion rates of 1.0, 3.0, and 10.0 μg  ·  kg−1  ·  ml−1. Arteriole diameter increased significantly from the baseline at the infusion rate of 10.0 μg  ·  kg−1  ·  ml−1 (18% from control). Venule diameter did not change from baseline value at any infusion rate. ICP did not change from baseline value at any infusion rate.

Conclusion: We conclude that PGE1 might be a suitable drug for induced hypotension in neurosurgery from the viewpoint of its small effect on the cerebral microvessels and ICP.
Plasma concentrations of ropivacaine following a single‐shot caudal block of 1, 2 or 3 mg/kg in children
Authors: Bösenberg A. T. , Thomas J. , Lopez T. , Huledal G. , Jeppsson L. , Larsson L. E.
Published: March 2003

Background: For documenting the properties of ropivacaine used for regional anaesthesia in children, the relationship between dose and resulting systemic exposure is essential. The aim of this pharmacokinetic part of a randomised, multicentre, double‐blind study was to determine the free and total plasma levels of ropivacaine in children aged between 4 and 12 years following a single‐shot caudal dose of 1, 2 or 3 mg/kg of ropivacaine for postoperative pain management.

Method: Following induction of a standardised general anaesthetic (halothane; nitrous oxide: oxygen 60:40), a caudal block using 1 ml/kg ropivacaine in concentrations of 1, 2 or 3 mg/ml was performed in 43 ASA I children (body weight 12–25 kg) scheduled for elective inguinal surgery. Blood samples were collected prior to and 15, 30, 45, 60 and 240 min after placement of the caudal block for determination of total and free ropivacaine plasma concentrations.

Results: The peak plasma concentration of total ropivacaine, reached within 15–241 min after the block, increased in proportion to dose, with mean values at 0.27, 0.64 and 0.90 mg/l following 1, 2 and 3 mg/kg respectively. The peak plasma level of free ropivacaine also increased in a dose‐proportional manner, with mean levels at 0.014, 0.030 and 0.042 mg/l. The highest individual peak plasma level of free ropivacaine was 0.070 mg/l, well below the threshold levels of CNS toxicity described in adults. No clinical signs of systemic toxicity were observed.

Conclusion: Following single‐shot caudal doses of 1–3 mg/kg in children up to 25 kg and aged between 4 and 12 years, plasma levels of free ropivacaine increase in proportion to dose and all were shown to be within safe limits.
Autocycling and increase in intrinsic positive end‐expiratory pressure during mechanical ventilation
Authors: Harboe S. , Hjalmarsson S. , Søreide E.
Published: March 2003

Modern ventilators are complicated electronic instruments with microprocessors and software, with the possibility of technical errors and problems such as autocycling. Despite autocycling being recognized as a problem in textbooks and reviews, there are few reports about autocycling in the literature. We report a case where a sudden increase in respiratory frequency due to autocycling resulted in a dangerous increase in intrinsic positive end‐expiratory pressure (intrinsic PEEP, PEEPi). We think our case illustrates that autocycling does occur, but that the exact underlying mechanism may be hard to document and understand for clinicians. To remedy this situation, we suggest that manufacture‐independent technical expertise should be established to evaluate incidents and suggest improvements.
Sympathetic nervous activation following subarachnoid hemorrhage: Influence of intravenous clonidine
Authors: Lambert G. , Naredi S. , Edén E. , Rydenhag B. , Friberg P.
Published: March 2003

Background: Subarachnoid hemorrhage is often accompanied by systemic complications and cerebral vasospasm. Elevated levels of circulating catecholamines may be involved in the pathophysiology behind these events. The alpha‐2‐agonist clonidine inhibits sympathetic outflow by a central mechanism. Unrestricted sympathoexcitation may be detrimental and administration of clonidine may be beneficial in these patients.

Methods: Using isotope dilution methodology, norepinephrine kinetic determinations, comprising determination of arterial norepinephrine concentration and rates of norepinephrine spillover to and removal, or clearance, from plasma, were performed on three occasions during the first week after subarachnoid hemorrhage in 25 patients. Eleven of these patients received clonidine (continuous i.v. infusion 5.8 ± 0.7 µg·kg−1·24 h−1) and the remainder, standard therapy. Initial results were compared with 17 healthy age‐matched subjects and eight patients suffering from severe traumatic brain injury without traumatic subarachnoid hemorrhage.

Results: Subarachnoid hemorrhage patients exhibited markedly elevated arterial plasma norepinephrine concentrations [3.74 ± 0.48, P < 0.001 vs. healthy subjects (1.59 ± 0.11 nmol/L) and P < 0.05 vs. head trauma patients (1.94 ± 0.29 nmol/L)]. The rate of clearance of norepinephrine from plasma in the subarachnoid patients was also significantly greater than that observed in the healthy subjects (2.66 ± 0.15 vs. 2.14 ± 0.15 L/min, P < 0.05) and the head trauma patients (2.00 ± 0.12 L/min, P < 0.05). Compared with both control groups, on admission the rate of spillover of norepinephrine to plasma following subarachnoid hemorrhage was markedly elevated (9.11 ± 1.12, P < 0.001). Clonidine treatment (continuous i.v. infusion 5.8 ± 0.7 µg·kg−1·24 h−1) did not reduce the increased rate of spillover of norepinephrine to plasma following subarachnoid hemorrhage.

Conclusion: Sympathetic nervous activity is markedly elevated following subarachnoid bleeding. Clonidine had no effect on the rate of norepinephrine spillover to, or clearance from, plasma in these patients. Clearly, further studies are required to elucidate the mechanisms responsible for generating sympathetic nervous activation following subarachnoid hemorrhage.
Accuracy of radial arterial pressure measurement during surgery under controlled hypotension
Authors: Yazigi A. , Madi‐Jebara S. , Haddad F. , Hayek G. , Jawish D.
Published: March 2003

Background: Radial arterial pressure underestimates the pressure in the aorta in several clinical situations. A central‐to‐radial pressure gradient was attributed to intense vasodilation. The aim of this study was to evaluate the accuracy of radial pressure monitoring during controlled hypotension achieved with profound arterial vasodilation.

Methods: Ten patients with ASA physical status I and II undergoing maxillofacial surgery under general anesthesia were enrolled in this prospective study. Radial and femoral arteries were cannulated and connected to a pressure monitoring system. Controlled hypotension was achieved with an infusion of nicardipine titrated to maintain MAP between 50 and 60 mmHg. Simultaneous radial and femoral systolic, mean and diastolic arterial pressures were recorded before, during and after controlled hypotension. Results were expressed as mean ± SD. Concomitant radial and femoral pressures were compared by a paired Student's test, P < 0.05 being significant.

Results: In all, 150 sets of arterial pressures measurement were obtained. There were no statistically significant differences between radial and femoral arterial pressures measured before, during or after controlled hypotension.

Conclusion: Radial arterial pressure is an accurate measure of central arterial pressure during controlled hypotension achieved with arterial vasodilation.
Carbon monoxide poisoning − a cause of increased QT dispersion
Authors: Gürkan Y. , Canatay H. , Toprak A. , Ural E. , Toker K.
Published: March 2003

Background: Carbon monoxide (CO) poisoning is associated with direct cardiovascular toxicity. QT dispersion (QTd) of the ECG is an indirect measure of heterogeneity of ventricular repolarization, which may contribute to ventricular arrhythmias. Our aim was to study QTd in patients with acute CO poisoning.

Methods:  CO intoxication was confirmed by arterial blood gas analysis. A control group consisted of age‐ and sex‐matched individuals admitted to the hospital for unrelated clinical conditions. 12‐lead ECG's were recorded on admission and repeated 1 week after discharge from the hospital. QT dispersion was defined as the difference between the greatest and the least QT intervals in any of the 12 leads.

Results:  Seventeen intoxicated patients, aged 5–46 years, had mean carboxyhemoglobin levels of 22.5 ± 11.1%. On admission, corrected QT intervals of the intoxicated patients were significantly increased compared to the control group (431 ± 18 ms vs. 404 ± 28 ms, P = 0.008), but not the QT interval (358 ± 25 ms vs. 345 ± 20 ms, P = 0.17). Mean QTd and cQTd values (46 ± 15 ms and 62 ± 13 ms) of the intoxicated patients were significantly increased compared to the control group (17 ± 4 ms and 33 ± 15 ms, P < 0.0001 for both). Both QTd and cQTd decreased significantly after discharge from the hospital (P = 0.0001).

Conclusion:  Although QT dispersion increased in patients with CO poisoning, none of ECG's showed ventricular arrhythmia. Increased QTd in the absence of QT interval prolongation may have a lowered arrhythmogenic potential of CO poisoning.
Parenteral ketoprofen for pain management after adenoidectomy: comparison of intravenous and intramuscular routes of administration
Authors: Tuomilehto H. , Kokki H.
Published: March 2003

Background: Different parenteral routes of administration of NSAIDs such as ketoprofen have not been properly compared in children. This study was designed to compare the analgesic efficacy of intravenous and intramuscular ketoprofen for pain management in children after day‐case adenoidectomy.

Methods: A total of 120 children, aged 1–9 years, who were scheduled to undergo adenoidectomy, were randomized to receive ketoprofen 2 mg/kg either intravenously with intramuscular placebo (n = 40) or ketoprofen 2 mg/kg intramuscularly with intravenous placebo (n = 40), or both intravenous and intramuscular placebo (n = 40) at induction of anesthesia. The study design was prospective and double‐blind with parallel groups. Pain was assessed at rest and during swallowing using the Maunuksela pain scale during 3 h after surgery, and fentanyl i.v. was given for rescue analgesia.

Results: Children in the Placebo group needed significantly more doses of fentanyl (72 doses) than either children in the intravenous group (47 doses) or children in the intramuscular group (51 doses) (P = 0.021). In addition, a higher proportion of children in the Placebo group than in the two ketoprofen groups (P = 0.03) demanded rescue analgesic. No difference in the need for rescue analgesia or in pain scores was found between the two ketoprofen groups. Children in the intravenous group had less pain than children in the Placebo group. The difference was significant during swallowing at 1 h after surgery (P = 0.046) and for the worst pain observed during swallowing for 3 h after surgery (P = 0.022). There were no differences between the three groups with respect to operation times, amount of perioperative bleeding, or rate or extent of adverse events.

Conclusion: The efficacy of intravenous and intramuscular ketoprofen was similar, and they both differed from placebo.
Anatomical study applied to anesthetic block technique of the superior laryngeal nerve
Authors: Furlan J. C.
Published: March 2003

Background: The topography of the internal branch of the superior laryngeal nerve (ibSLN) was prospectively studied to evaluate the greater horn of the hyoid bone (ghHB) and the incisura of the thyroid cartilage (iTC) as anatomical repairs in laryngeal anesthetic block. Factors such as gender, ethnicity and side of the neck were also analyzed concerning their influence in the ibSLN position.

Methods: One hundred neck dissections were performed in 50 human cadavers bilaterally identifying the ibSLN, the ghHB and iTC. The distance between the ghHB and ibSLN in the cranio‐caudal direction (dHB), and the distance between the iTC and the ipsilateral thyrohyoid membrane ostium (dTC) were measured. Furthermore, the results were statistically analyzed according to ethnicity, gender and side of the neck.

Results: The ibSLN was juxtaposed to the apex ghBH in 31 out of 100 dissections. The mean dHB was 2.4 mm, and mean dTC was 33.4 mm. The statistical analysis did not identify any significant difference regarding those distances between the groups in terms of ethnicity, gender and side of the neck.

Conclusion: The ibSLN was often dissected very close to the ghHB, and this result was not influenced by any factor studied. Therefore, the ghHB can be considered a good anatomical repair to localize the ibSLN in the local block of the larynx. Furthermore, the dTC could frequently be reached by routinely used nerve block needle. However, a few anatomical variations may occur, resulting in a low failure rate of this anesthetic procedure.
Central anticholinergic syndrome in a child undergoing circumcision
Authors: Schultz U. , Idelberger R. , Rossaint R. , Buhre W.
Published: March 2003

We describe one of the few pediatric cases of central anticholinergic syndrome (CAS) in an 8‐year‐old boy undergoing elective surgery. Deep sedation, inadequate response to stimuli and reduced muscular tone of the upper airway resulting in airway obstruction were the clinical manifestations of CAS. The symptoms resolved immediately after administration of physostigmine. This case illustrates the importance of considering central anticholinergic syndrome as a differential diagnosis in children if prolonged sedation after general anesthesia occurs.
Superior prolonged antiemetic prophylaxis with a four‐drug multimodal regimen – comparison with propofol or placebo
Authors: Hammas B. , Thörn S‐E. , Wattwil M.
Published: March 2003

Background:  The purpose of this study was to compare the effects of a low‐dose propofol infusion with a four‐drug multimodal regimen for prophylaxis of postoperative nausea and vomiting (PONV).

Methods: PONV was studied in two patient groups with a known high incidence. Through a stratified randomization, 60 patients undergoing breast surgery and 120 patients undergoing abdominal surgery were randomized to three groups of equal size: the propofol group (P), the multidrug group (M) and the control group (C). All patients received general anesthesia, induction with propofol and maintenance with sevoflurane. After induction, patients in the P group received a continuous infusion of propofol 1 mg/kg/h during the operation and the first 4 postoperative h. Patients in the M group received dexamethasone 4 mg and three antiemetics, ondansetron 4 mg, droperidol 1.25 mg and metoclopramide 10 mg i.v. In the control group no prophylaxis was given. Nausea and pain were evaluated by incidence and a visual analog scale (0–10 cm). All emetic episodes were noted by the staff during the first 4 h and by the patients during the next 20 h.

Results: The overall incidence of PONV during the first 24 h postoperatively was significantly lower in the M group (24%) than in the P group (49%) (P<0.01) or the C group (70%) (P<0.001). The incidence of PONV increased significantly both in patients undergoing breast surgery and abdominal surgery after termination of propofol. The number of patients who vomited was significantly lower in the M group, both in breast surgery patients (5%) and abdominal surgery patients (3%) compared to patients in the propofol groups (breast 16% NS; abdominal 29%, P<0.05) and in the control groups (breast 37%, P<0.01; abdominal 29%, P<0.01).

Conclusion: The incidence of PONV is very high in patients undergoing breast and abdominal surgery. In the present study antiemetic prophylaxis with a combination of droperidol, ondansetron, metoclopramide and dexamethasone was more effective in preventing PONV, especially vomiting, than a postoperative low‐dose infusion of propofol, which had a short lasting effect.
Evaluation of remifentanil as single drug for awake fiberoptic intubation
Authors: Puchner W. , Egger P. , Pühringer F. , Löckinger A. , Obwegeser J. , Gombotz H.
Published: March 2003

Background:  Awake fiberoptic intubation is the standard of care for difficult airway management. Quality and success of this technique depend on the experience of the intubating physician and the proper preparation of the patient. The aim of this study was to compare remifentanil (R) as single agent to the combination of fentanyl (F) and midazolam (M), which have been the drugs for analgesia and sedation for this procedure.

Methods:  Seventy‐four adult patients requiring nasotracheal intubation were randomly assigned to one of two groups. In group I, (n=37) R was administered in incremental dosages (0.1–0.25–0.5 µg/kg/min) by an infusion pump according to comfort, level of sedation and respiratory depression. In group II, (n=37) analgesia and sedation was achieved by F 1.5 µg/kg and doses of between 1 and 10 mg M, titrated to the individual needs. Patient reactions like grimacing, movement and coughing during intubation were assessed, as well as patient recall of the procedure. Haemodynamic and respiratory parameters were continuously recorded.

Results:  Group I patients better tolerated nasal tube passage (P<0.001) and laryngeal tube advancement (P<0.001) than group II. Remifentanil better suppressed hemodynamic response to nasal intubation (P<0.001). No significant difference in respiratory data was recorded. In group I more recall of the procedure was observed (six vs. zero patients, P<0.05).

Conclusion:  Remifentanil in high doses, as the single agent for patient preparation for awake fiberoptic intubation seems to improve intubating conditions, quality and reliability of the procedure. However, a higher incidence of recall is to be expected.
Development and evaluation of a video program for presentation prior to elective cardiac surgery
Authors: Roth‐Isigkeit A. , Ocklitz E. , Brückner S. , Ros A. , Dibbelt L. , Friedrich H.‐J. , Gehring H. , Schmucker P.
Published: March 2003

Background:The objective of the present study was to develop and evaluate the effects of a preparatory videotape on endocrine stress responses of patients prior to cardiac surgery and to analyze patient acceptance of this video for preoperative preparation.

Methods:101 male patients prior to elective cardiac surgery were enrolled into the study. On the day before surgery, patients were assigned to one of the following groups: group 1 (n = 51) saw a video with realistic information about the upcoming perioperative procedure, and group 2 (n = 50) saw a video of the same length without surgery‐related information. Venous blood was sampled before and 15 min after the video presentation. On the second postoperative day, patients filled in a questionnaire concerning their experiences of having preoperatively watched the video.

Results:After viewing the video, blood levels of cortisol, adrenocorticotropic hormone (ACTH), beta‐endorphin, prolactin, epinephrine and norepinephrine in patients of group 1 were not significantly different compared to values measured before the video presentation. In patients of group 2, blood levels of cortisol, ACTH, prolactin and norepinephrine were significantly lower after video presentation compared to values obtained before the video. Patients of group 1 (compared to group 2) were significantly more often of the opinion that the video had helped in the preparation for surgery, and that they would like to repeat this adjunct preoperative video preparation in another similar situation.

Conclusion:We conclude from our results that (i); cardiac surgical patients prefer preoperatively an adjunct surgery‐related video preparation to a non‐specific video presentation, and that (ii); preoperative preparation with realistic information about the upcoming medical procedure in patients undergoing cardiac surgery does not lead to an increase in endocrine stress hormone levels.
Pulse contour analysis versus thermodilution in cardiac surgery patients
Authors: Rauch H. , Müller M. , Fleischer F. , Bauer H. , Martin E. , Böttiger B. W.
Published: March 2003

Background:  Previous studies have demonstrated that there is a lack of agreement between intermittent cold bolus thermodilution (ICO) and a semicontinuous method with dilution of heat (CCO) in cardiac surgical patients following hypothermic extracorporeal circulation (HCPB). Therefore, the aim of the present study was to compare both ICO and CCO with continuous pulse contour analysis (PCCO): a method based on a fundamentally different principle of determining cardiac output (CO).

Methods:  A prospective criterion standard study of 25 cardiac surgery patients undergoing HCPB. Cardiac output was determined using the three methods (ICO, CCO, and PCCO) before and after HCPB up to 12 h after arrival on the ICU. Bias and precision were evaluated.

Results:  A total of 380 triple determinations of CO could be analyzed. During the entire study period bias PCCO‐ICO was −0.14 l*/min (precision 1.16 l*/min) and bias CCO‐ICO was −0.40 l*/min (precision 1.25 l*/min). Up to 45 min after bypass PCCO agreed with ICO (bias −0.21 l*/min, precision 1.37 l*/min), while bias CCO‐ICO was −1.30 l*/min (precision 1.45 l*/min).

Conclusion:  The agreement between PCCO and ICO in contrast to CCO in the first 45 min after HCPB indicates that CCO underestimates CO during this period.
Interrater reliability of diagnosing complex regional pain syndrome type I
Authors: Perez R. S. G. M. , Burm P. E. T. , Zuurmond W. W. A. , Giezeman M. J. M. M. , Van Dasselaar N. T. , Vranken J. , De Lange J. J.
Published: March 2003

Background:  Diagnosis of complex regional pain syndrome type I (CRPS I) is based on clinical observation of symptoms. As little information is available on the reliability of CRPS I diagnosis, we evaluated the agreement between therapists with regard to the presence and severity of CRPS I and its symptoms.

Methods:  The interrater reliability was evaluated in 37 presumed CRPS I patients by three observers; one consultant anesthesiologist and two resident anesthesiologists. Patients were assessed on the basis of Veldman's CRPS criteria.

Results:  The interrater reliability for diagnosing CRPS I was good for the majority of observer combinations. The percentage of agreement for the absence or presence of CRPS I was good (88%−100%). Cohen's Kappa's ranged from 0.60 to 0.86. The agreement for the mean symptom score ranged from 70.2% to 88.6%; Kappa's were lower and showed more variation. Interrater reliability for assessment of the severity of CRPS I and its symptoms was poor. Factors influencing the interrater reliability were symptom type, individual observers and sample population.

Conclusion:  Diagnosing CRPS I can be performed on the basis of clinical observation. Further assessment of severity of CRPS I and its symptoms should be performed with reliable and valid measurement instruments.