bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparative histopathology of epidural hydrogel and silicone elastomer catheters following 30 and 180 days implant in the ewe
Authors: COOMBS D. W. , COLBURN R. W. , DELEO J. A. , HOOPES P. J. , TWITCHELL B. B.
Published: January 2009

New catheter materials, termed Hydrogels, have been developed recently that are stiff until exposed to hydration. The purpose of this study was to compare the 30 and 180 day histopathology of catheters composed of a common silicone elastomer versus a Hydrogel elastomer blend (HEB). Epidural catheters composed of either silicone or HEB were implanted in 19 yearling ewes for either 30 or 180 days. The degree of fibrotic reaction in the epidural space, muscle and subcutaneous tissue was assessed using both histopathology and quantitative imaging analysis. A separate subset of three ewes were implanted with HEB epidural catheters connected to subcutaneously implanted ports through which twice weekly injections of saline were given. There was no evidence of significant neurotoxicology associated with either the silicone or the HEB catheter materials. However, the silicone elastomer group had a quantifiably greater degree of fibrosis than the HEB group of both implant durations. The mean cross sectional area (sq. mm) of epidural pericatheter fibrosis was significantly smaller in the HEB group compared with the silicone group (0.491 in the HEB group and 1.585 in the silicone group at 30 days [P = 0.02] and 0.28 and 1.401 at 180 days [P 0.0001]. The HEB catheter was easily inserted with standard epidural needles facilitated by the inherent stiffness of the catheter prior to hydration. HEB catheters remained patent throughout 30 days of saline injections per implanted ports. Silicone catheters demonstrated increased fibrosis relative to the HEB catheter material in the epidural space and in subcutaneous tissue.
Ephedrine enhances analgesic effect of morphine
Authors: TEKOL Y. , TERCAN E. , ESMAOǦLU A.
Published: January 2009

Morphine–ephedrine interaction on analgesia was studied in mice (n = 240) and in post–operative patients (n = 32). It was found that combining morphine and ephedrine enhances analgesia which is not significantly different from the effect of morphine given alone at double dose.
Sudden cardiorespiratory arrest after renal transplantation in a patient with diabetic autonomic neuropathy and prolonged QT interval
Authors: REISSELL E. , YLI–HANKALA A. , ORKO R. , LINDGREN L.
Published: January 2009

A 31–yr male with insulin dependent diabetes mellitus for 20 years underwent general anaesthesia for renal transplantation. During transfer from operating theatre to ICU he developed bradycardia advancing to ventricular fibrillation and had to be resuscitated. Bradycardia did not respond to atropine. Postoperative autonomic nervous function tests showed advanced autonomic neuropathy. He was found to have constantly prolonged QTc interval in his pre– and postoperative ECGs (462–503 ms). Prolongation of QTc interval could be used as a valuable predictor of postoperative cardiac complications in diabetic patients with autonomic neuropathy.
Retracted: Influence of volume replacement with different HES–solutions on microcirculatory blood flow in cardiac surgery
Authors: BOLDT J. , ZICKMANN B. , RAPIN J. , HAMMERMANN H. , DAPPER F. , HEMPELMANN G.
Published: January 2009

A variety of hydroxyethyl starch (HES) preparations with different molecular weight average (Mw) and molar substitution (MS) is available for volume replacement during acute normovolemic haemodilution (ANH). Particularly with regard to microcirculation, the ideal solution for volume therapy has not been found.

A 5th group without ANH served as a control (10 patients in each group). In addition to systemic haemodynamics and various laboratory parameters, skin capillary blood flow was measured by laser Doppler flowmetry. Laser Doppler flow (LDF) was monitored simultaneously at the patient's forehead and forearm. Changes in systemic haemodynamics were similar in all ANH–patients. Systemic vascular resistance (SVR) was lowest after infusion of HES 200/0.5. The most pronounced increase in plasma viscosity was in patients of group 1 (450/0.7) (P<0.05) and plasma viscosity remained highest during the entire investigation period in these patients. After ANH, skin capillary blood flow measured at the forehead decreased in all patients except in patients of group 2 (200/0.5: max. + 18%). Group 3 (200/0.62) showed the highest decrease in forehead–LDF. During CPB, forehead–LDF decreased significantly in groups 3 (200/0.62) and 4 (40/0.5). At the end of the operation, LDF was most reduced in groups 1 (– 32%) and 3 (– 33%). Forearm–LDF increased in all ANH–patients. Immediately after ANH this increase was lowest in group 3 (200/0.62). In the further course of the investigation, no more differences were seen in any HES patients. The different HES preparations showed a different microcirculatory response. 6% HES 200/0.5 seems to be overall most suitable for volume replacement in cardiac surgery patients undergoing acute normovolemic haemodilution (ANH) due to the best effects on microcirculatory skin perfusion assessed by laser Doppler flow. HES 6% 200/0.62 showed the overall least positive effects with regard to skin capillary blood flow in this situation.
An assessment of prilocaine as a topical anaesthetic agent for fibreoptic bronchoscopy in comparison with lidocaine
Authors: THAM E. J. , MORRIS S. , WRIGHT E. M. , CAMPBELL I. A. , MAPLESON W. W.
Published: January 2009

We have evaluated prilocaine as a topical anaesthetic agent for fibreoptic bronchoscopy in comparison with lidocaine in terms of efficacy and safety. Forty patients were included in a randomised double‐blind parallelgroup study. Efficacy was assessed using visual analogue scales, a patient ranking scale and the number of doses of local anaesthetic and intravenous sedative required. Measures of toxicity included peak plasma concentration of local anaesthetic, whether supplementary oxygen was needed and change in methaemoglobin concentration. For most of the outcome variables, the medians and quartiles were similar for the two local anaesthetics. However, the median peak plasma concentration of prilocaine (0.5 μg·ml‐1) was less than onethird that of lidocaine (1.76 μg·ml‐1). The merits and hazards of using multiple–regression modelling to improve the precision of the analysis of the results are considered. We conclude that prilocaine can be used successfully as a topical anaesthetic agent for fibreoptic bronchoscopy and is associated with a lower risk of toxicity.
Ventilation with rigid bronchoscopes. Evaluation of resistance by pressure drop by a proposed international standard
Authors: ECKERBOM B. , LINDHOLM C. E.
Published: January 2009

The ISO 8600–2–1 draft standard concerns measuring methods for ventilation properties in rigid bronchoscopes. Two lung models were designed in accordance with this draft, one for conventional ventilation, and the other for jet–ventilation (venturi ventilation).
Cardiovascular effects of moderate normovolaemic haemodilution during enflurane–nitrous oxide anaesthesia in man
Authors: VAN DER LINDEN P. , WATHIEU M. , GILBART E. , ENGELMAN E. , WAUTREGHT J.–C. , LENAERS A. , VINCENT J.–L.
Published: January 2009

The cardiovascular effects of mild normovolaemic haemodilution during enflurane–nitrous oxide anaesthesia were studied in 20 patients with normal cardiac function before, during and after total hip replacement. After induction of anaesthesia, patients were randomly allocated to one control group (C), or one haemodiluted group (H) where Hct was decreased to 30% by replacement of blood volume by an identical volume of hydroxyethyl starch 200/0.5. Each patient was monitored with a pulmonary artery catheter allowing the measurement of right ventricular ejection fraction. During haemodilution, stroke index and right ventricular end–diastolic volume index increased from 33.1 7.9 to 39.3 7.1 ml M‐2 and from 73.8 20.3 to 94.9 18.5 mlM‐2 respectively (mean s.d., both P<0.05). However, heart rate decreased so that cardiac index did not change. O2 delivery decreased significantly (from 389 70 to 31163 ml–min‐1 –m‐2; P<0.05), but was not different to the control group. O2 consumption was maintained by an increase in O2 extraction. During the surgical procedure, cardiac index was higher in the haemodiluted group than in the control group, so that O2 delivery was similar in the two groups. O2 consumption tended to be greater in the haemodiluted group.
The contractile response of thiopental in large and small ovine airways
Authors: THULESIUS L. , THULESIUS O.
Published: January 2009

The present study addresses the question of bronchial reactivity towards thiopental using pharmacological assay and ultrastructural analysis with transmission electron–microscopy in sheep airways. Smooth muscle strips of the upper, middle and lower trachea and small size bronchial rings of sheep were investigated using organ bath technique with monitoring of isometric tension in response to thiopental (10‐7–10–4M), histamine (10_4M) and carbachol (10‐8M). Thiopental elicited contractile responses in the large airways, with most marked contractions in the upper trachea. In the small lobar bronchi thiopental caused a biphasic response with predominant relaxation. Similar reactions could be elicited by histamine. Ultrastructural studies showed a large number of mast cells with equal distribution throughout the bronchial tree. Histamine release from bronchial tissue was detected by bioassay after thiopental challenge. It can be concluded that thiopental at a concentration of 10 4M releases histamine from mast cells within the airways with consequent constriction in the trachea and mainly dilatation in the smaller intralobular airways. Under these conditions therefore, one does not necessarily expect a net change of airflow resistance with thiopental anaesthesia.
Repeated episodes of myocardial ischaemia during combined thoracic epidural – isoflurane anaesthesia
Authors: SIGURDSSON G. H. , BROUWER R. P. , THOMSON D.
Published: January 2009

A patient with a history of coronary artery disease developed new ST segment depressions in the ECG registration during a low dose (0.7%) isoflurane anaesthesia that was combined with a continuous thoracic epidural analgesia. Simultaneously a small decrease in mean arterial blood pressure (MAP) was noted. During the next 5 min these changes were followed by a severe drop in MAP (from 88 to 60 mmHg) and in cardiac output from 5.5 to 3.2 L/min. When isoflurane was discontinued both the ECG and the cardiovascular changes returned to the previous condition. Later, when 0.5% isoflurane was restarted, the ECG changes reappeared within ten min, but disappeared once again when isoflurane administration was discontinued. Thus, this patient had repeated episodes of myocardial ischaemia which were associated with the use of low dose isoflurane. Although isoflurane–induced “coronary steal” may appear as a likely cause of these ischaemic episodes, it is possible that the thoracic epidural had synergistic action and rendered the patient exceptionally sensitive to minor changes in perfusion pressure.
Addition of atracurium to lidocaine for intravenous regional anaesthesia
Authors: ELHAKIM M. , SADEK R. A.
Published: January 2009

This study was undertaken to examine the possible clinical advantages of using muscle relaxant with intravenous regional anaesthesia, (IVRA). Forty unpremedicated adult patients undergoing hand surgery were randomly allocated to receive either 40 ml 0.5% lidocaine or 40 ml 0.5% lidocaine with 2 mg of atracurium. The atracurium group of patients had a significantly greater degree of muscle relaxation, easier reduction of fractures, and better operative conditions (P < 0.01). Less pain was also reported during surgery (P < 0.025), and 5 and 15 min after release of the tourniquet (P < 0.01). Clinically, there was no difference in the speed of onset of block between the two groups. It is concluded that the addition of atracurium to lidocaine improves the operating condition during IVRA with less pain during and after surgery.
Immediate and prolonged effects of pre– versus postoperative epidural analgesia with bupivacaine and morphine on pain at rest and during mobilisation after total knee arthroplasty
Authors: DAHL J. B. , DAUGAARD J. J. , RASMUSSEN B. , EGEBO K. , CARLSSON P. , KEHLET H.
Published: January 2009

Thirty–two patients scheduled for total knee arthroplasty were randomized to receive an identical epidural blockade initiated 30 min before surgical incision (N = 16), or at closure of the surgical wound (N=16). Before induction of general anaesthesia the epidural catheter was tested with bupivacaine 7.5 mg ml‐1, 2 ml. General anaesthesia was induced with thiopentone, pancuronium or atracurium, and fentanyl 0.1–0.3 mg, and maintained with N2O/O2 and enflurane. The epidural regimen consisted of a bolus of 16 ml of bupivacaine 7.5 mg ml‐1 plus morphine 2 mg, and continuous infusion of bupivacaine 1.25 mg ml‐1 plus morphine 0.05 mg–ml‐1, 4 mlh‐1 for the first 24 h, and bupivacaine 0.625 mg ml‐1 plus morphine 0.05 mg·ml‐1, 4 ml . h‐1, for the next 24 h after operation. Additional morphine 2.5–5 mg was administered i.v. or i.m. for the first 24 h postoperatively, and ketobemidone or morphine 5–10 mg orally or rectally from 24 h to 7 d postoperatively, on request. Paracetamol 1000 mg every 8 h was administered from 48 h to 7 days postoperatively. No significant differences were observed in request for additional opioids, or in pain scores at rest or during mobilisation of the operated limb, during or after cessation of the epidural regimen. These results do not suggest timing of analgesia with a conventional, continuous epidural regimen to be of major clinical importance in patients undergoing total knee arthroplasty.
High–frequency jet ventilation vs continuous positive airway pressure for differential lung ventilation in patients undergoing resection of thoracoabdominal aortic aneurysm
Authors: GODET G. , BERTRAND M. , ROUBY J. J. , CORIAT P. , HAG B. , KIEFFER E. , VIARS P.
Published: January 2009

Twenty patients, scheduled for surgical resection of thoracoabdominal aortic aneurysm were divided into two groups according to the type of differential lung ventilation used during graft replacement of the descending thoracic aorta. In the high–frequency jet ventilation (HFJV) group of ten patients, HFJV was applied to the left lung once collapsed and retracted by the surgeon, the patient lying in the right lateral decubitus and being intubated by a Carlens' tube. In the continuous positive airway pressure (CPAP) group of ten patients, CPAP was applied to the left lung at the same mean airway pressure as HFJV (1 kPa). Before anaesthetic induction, an arterial and a Swan–Ganz catheter were inserted for cardiovascular monitoring. The same anaesthetic technique using fentanyl 6 μg·kg‐1, flunitrazepam 0.02 mg kg‐1 and pancuronium 0.1 mg kg‐1 was used for each patient. Haemodynamic and respiratory measurements were made: 15 min after positioning the patients in the right lateral decubitus using two–lung ventilation; 15 min after collapse and retraction of the left lung using one–lung ventilation and 15 min after using differential lung ventilation with CPAP or HFJV.

Left lung collapse with conventional one–lung ventilation induced a dramatic decrease in arterial oxygenation: Pao2/Fio2 ratio decreased from 43 6 kPa to 20 8 kPa, alveolo–arterial oxygen difference increased from 24 7 kPa to 72 11 kPa and pulmonary shunt increased from 17 2% to 37 3%. Whereas differential lung ventilation with CPAP did not improve any of the respiratory parameters measured, differential lung ventilation with HFJV, significantly increased Pao2/Fio2 ratio to 41 14 kPa. Therefore, since HFJV improves gas exchange without altering the conditions of surgical comfort, different lung ventilation with HFJV appears to be superior to differential lung ventilation with CPAP.
Antihistaminergic pretreatment prevents tissue extravasation of albumin from intra–abdominal trauma in rats
Authors: ÅKERSTRÖM GUNNAR , LISANDER BJÖRN
Published: January 2009

Intra–abdominal surgery causes a loss of plasma into tissues within and around the abdomen, endangering tissue viability. Mast cells, containing histamine, are abundant in the abdominal cavity. In a model of mechanical intra–abdominal trauma, we investigated whether pretreatment with histaminergic H, and H2 receptor blockers counteracts this extravasation. In Wistar rats under chloralose anaesthesia, tissue clearances of labelled albumin were determined by a double isotope technique. Four groups were studied: Traumatized rats, pretreated (n=10) and non–pretreated (n = 9): non–traumatized rats; pretreated (n=10) and nonpretreated (n = 9). In the traumatized rats, given pyrilamine 10 mg kg‐1 (H1) plus cimetidine 25 mg kg‐1 (H2) just before the trauma, the blockers prevented the haemoconcentration from loss of plasma and the drop in arterial pressure during the very trauma procedure, observed among non–pretreated rats. Furthermore, they significantly decreased the clearance of albumin in the abdominal wall and the pancreas. In the non–traumatized animals, the blockers lowered arterial pressure and heart rate. In conclusion, the anti–hista–minergic pretreatment decreased the trauma induced leakage of albumin, by mechanisms which may involve readjustments of pressures and flows in capillaries as well as a prevention of histamine effects on capillary permeability.
Transoesophageal echocardiography and acoustic quantification in assessing regional left ventricular wall motion
Authors: HULTMAN J. , PALMGREN I. , LANDELIUS J. , ANDREN B.
Published: January 2009

Acoustic Quantification (AQ) is a technique based on analysis of ultrasonic integrated backscatter. It enables a real time detection of blood – tissue borders and numbers the end–diastolic and end–systolic areas throughout the cardiac cycle. AQ added to the 2D image therefore offers an on–line estimate of global ventricular function in the operating room. Since AQ is dependent on a good 2D image as well as adjustment of both transmit–and time gain control the question arises whether this leads to a different assessment, compared to the 2D image only, of off–line assessment of regional left ventricular wall motion (LVWM). Twenty–three consenting patients scheduled for elective coronary bypass grafting were studied. A total of 31 observations were performed and divided into 21 short axis and 10 three chamber long axis views. Regional LVWM score was assessed off–line (video recordings postoperatively) by two independent readers on two occasions. There was no intra–reader difference in assessment of regional LVWM in the short axis view when AQ was added to the 2D image. On the other hand, the interreader difference was highly significant both without and with AQ (P = 0.0001) in this view. In the long axis view the intra–reader difference was significant (P = 0.0008 and P = 0.004 respectively), while the inter–reader difference was non–significant. However, the overall intrareader and inter–reader agreement was 78% or higher except for the intra–reader difference in the long axis view. Our conclusion is that AQ added to the 2D image does not alter LVWM score in the short axis but in the three chamber long axis view.
Assessment of sensory block in epidural anaesthesia by electric stimulation
Authors: DYHRE H. , RENCK H. , ANDERSSON C.
Published: January 2009

The onset of sensory block in lumbar epidural anesthesia was investigated in 26 patients, aged 18 to 84 years, employing the loss of discrimination to cold and pinprick, as well as by determining threshold electric stimulation (threshold intensities). A standard dose of 2% mepivacaine with adrenaline, 5 μg ml‐1, (0.1 ml per cm body height) was given and the patients' ability to discriminate stimuli within dermatomes T8, T10, T12, L2, L4 and SI was investigated at five min intervals for 30 min after injection. From the results of the study it is concluded that i) The interval to peak analgesic efficacy of the anaesthetic solution used is < 30 min when assessments are based on the patients' ability to discriminate cold or pinprick but > 30 min when determinations of threshold intensities are employed, ii) Cold discrimination is lost earlier than discrimination to pinprick and at lower threshold intensities, iii) Threshold intensities describe the time course of onset of sensory block more precisely than results of testing by cold or pinprick, iv) The onset of sensory block was found to be positively correlated to the age of patients in the following respects: a) Threshold intensities during early onset in all investigated dermatomes except L2. b) Intensity of block in T8, T10, and SI at the end of the study period, c) Time to loss of discrimination to cold and pinprick in T12, L2 and SI, and d) Threshold intensities at loss of discrimination to cold and pinprick. We propose that determinations of threshold intensities offer distinct advantages over conventional testing by cold and pinprick discrimination, especially when detailed analyses of the sensory blocking effects of local anaesthetic drugs are being investigated.
Traumatic or septic aortic regurgitation: diagnosis by oesophageal echocardiography
Authors: HABRE W. N. , VAN GESSEL E. F. , MAMIE CH. , CANTIENI R. , SUTER P. M.
Published: January 2009

Severe aortic regurgitation was discovered in a young man 21 days after blunt chest trauma and after a prolonged febrile state with positive blood cultures. Using transoesophageal echocardiography (TEE), it was possible to make the differential diagnosis between traumatic rupture and endocarditis as the cause of valvular insufficiency. The use of TEE in the initial evaluation of severe thoracic trauma with an unclear clinical picture is recommended. This method is easy to use at the bedside and gives precise information on the aortic valve and the ascending aorta.
A multifactorial analysis of the spread of epidural analgesia
Authors: CURATOLO M. , ORLANDO A. , ZBINDEN A. M. , SCARAMOZZINO P. , VENUTI F. S.
Published: January 2009

The controversies about the factors determining the spread of epidural analgesia are partly due to inappropriate methodology or sample size of previous studies. We performed a multivariate regression analysis on 803 ASA class 1–2 non–atherosclerotic adults, undergoing lumbar epidural anaesthesia according to a predefined standardised procedure. The spread of epidural analgesia is more accurately studied by analysing dose/ segment (R2 = 0.671) instead of spread (R2 = 0.271) as dependent variable. The impact of local anaesthetic (2% lidocaine C02 or 0.5% bupivacaine) and addition of adrenaline is not significant. Spread significantly increases with increasing age, weight, body–mass index, dose of local anaesthetic, addition of fentanyl, higher site of injection, and decreasing body height. The impact of age and dose is higher under the age of 40 and at doses lower than 20 ml. Increasing the total dose increases the dose needed to block one spinal segment. Unknown idiosyncratic factors still determine a certain proportion of the sample variance. The addition of adrenaline to lidocaine and the use of bupivacaine improve the predictability of spread. In conclusion, we found clinically significant correlations between a group of factors and epidural spread. Alternative anaesthetic solutions lead to different degrees of predictability.
The effect of plain 0.5% 2–chloroprocaine on venous endothelium after intravenous regional anaesthesia in the rabbit
Authors: SUZUKI N. , PITKANEN M. , SARIOLA H. , PALAS T. , ROSENBERG P. H.
Published: January 2009

The possible venous endothelial toxicity of 0.5% 2–chloroprocaine without additives in intravenous regional anaesthesia (IVRA) was evaluated in rabbits. After exsanguination of a hind limb with an Esmarch's bandage a neonatal blood pressure cuff around the thigh was inflated (250 mmHg). For IVRA 4 ml of either plain 0.5% 2–chloroprocaine (pH 3.7), 0.9% NaCl (pH 6.0) or acidified NaCl (pH 3.7) was injected i.v. to the exsanguinated limb in a randomized, double–blind fashion. Each group comprised 15 rabbits. Eleven rabbits received 4 ml of 0.5 M or 1.0 M KC1, for the production of positive controls. Two hours after injection of the test solution the tourniquet was deflated and venous biopsies were taken one and 24 hours later for histological and immunocytochemical examination. Five to eight 24–hour samples from each group were also processed for electron microscopy. A macroscopic thrombus formation was observed in four rabbits after KC1 and in two after acidified NaCl administration. No inflammatory changes were observed at histologic and immunocytochemical examination of any of the vein samples. Electron microscopy revealed that KC1 had caused severe damage to the venous endothelium of four out of five samples and acidified NaCl had caused moderate damage to the endothelium of two out of seven samples. 2–chloroprocaine had caused moderate damage in four and severe damage in two of the vein samples; two samples were normal. No thrombus formation occurred. It is concluded that additive–free 2–chloroprocaine caused damage to the venous endothelium in rabbits when used for IVRA.
The Gothenburg study of perioperative risk
Authors: ARVIDSSON S. , OUCHTERLONY J. , NlLSSON S. , SjÖSTEDT L. , SvARDSUDD K.
Published: January 2009

The Gothenburg study of Perioperative Risk is a prospective clinical–epidemiological study designed to elucidate factors affecting the perioperative risk in unselected adult patients undergoing elective general or orthopaedic surgery. In this report reference data regarding preoperative characteristics and postoperative complications are presented. 1770 adult patients scheduled for elective general, urological, peripheral vascular or orthopaedic operative procedures were invited to a preoperative clinic. 81% agreed to participate and were assessed in a standardised way by means of questionnaires, interview, physical examination and laboratory screening. 82% had a previous or present condition in the medical history of some concern to the assessor. 71% had a finding of significance on physical examination. In 8% the assessment prompted further investigations or precautions. Throughout their hospital stay, all the 1361 participating patients were visited daily by an especially trained nurse with the task of registering the occurrence of complications. In 30% an untoward event occurred postoperatively – in 1% a severe one, in 21% a mild event, and in 8% an intermediate one. The complication rate was higher in vascular surgery (69%) than in orthopaedic (33%) and general/urological surgery (26%). Not only the severe and intermediate but also the mild complications affected the number of days in hospital.
Propofol–nitrous oxide versus thiopentone–isoflurane–nitrous oxide anaesthesia for uvulopalatopharyngoplasty in patients with sleep apnea
Authors: HENDOLIN H. , KANSANEN M. , KOSKI E. , NUUTINEN J.
Published: January 2009

A randomized prospective study was performed to compare the recovery in 41 patients undergoing uvulopalatopharyngoplasty (UPPP) with either propofol‐nitrous oxide‐fentanyl or thiopentone‐isoflurane‐nitrous oxide‐fentanyl anaesthesia. The patients were referred to UPPP after examination including polysomnography and otorhinolaryngological examination. The propofol group received propofol 2 mg·kg‐1 for induction followed by an infusion of 10 mg·kg‐1·h‐1 after intubation. The thiopentone‐isofiurane group received 5 mg·kg‐1 of thiopentone for induction followed by isoflurane (0.5–2%) after intubation. Other medication was similar in both groups. In the propofol group the patients had a significantly better oxygen saturation during the first postoperative hour (P < 0.05), and a higher rate of breathing (P < 0.05), indicating a more rapid recovery of the physiologic control of breathing. Pain as measured by visual analogue score was lower (P < 0.05) during the second postoperative hour compared with the isoflurane group. Apneic episodes occurred with similar frequency in both groups, and they were related to the severity of obstructive sleep apnea (OSA). We conclude that propofol is preferable to thiopentone‐isofiurane in UPPP operations, because physiologic respiratory control recovers faster and postoperative pain is less intense.
Possible errors in diagnosis of bacterial sinusitis in tracheal intubated patients
Authors: WESTERGREN V. , FORSUM U. , LUNDGREN J.
Published: January 2009

Bacterial sinusitis is recognized as a complication of prolonged nasotracheal intubation. Verification of the diagnosis, however, requires culture findings from a “true” sample from the maxillary antrum. A “true” antral sample can only be obtained after passing either the nasal or oral mucosae with their rich aerobic and anaerobic bacterial flora.

No properly controlled study has been made into the problem of contaminated samples in bacterial sinusitis complicating prolonged nasotracheal intubation. The design of the study was a case series in an intensive care unit. The patients had either had endotracheal tube or tracheal cannula for seven days or were septic, having an endothracheal tube or a tracheal cannula and therefore due to an investigation of infection foci. Antral cultures obtained via the canine fossa were compared with oral cultures to exclude the contribution of oral bacterial contamination and thereby to improve the reliability of diagnosis based on culture results. The contamination rate was lowered significantly from 67% to 5% when an area of free bone was prepared in the canine fossa thus avoiding instrument contact with the oral mucosa.

A high contamination risk can be dealt with by adjusting the technique of sampling thereby increasing the culture reliability.
Effects of five amino–amide local anaesthetic agents on human polymorphonuclear leukocytes measured by chemiluminescence
Authors: CEDERHOLM I. , BRIHEIM G. , RUTBERG H. , DAHLGREN C.
Published: January 2009

The aim of this study was to assess the influence of five amino–amide local anaesthetic agents on the production of oxygen metabolites in the human polymorphonuclear leukocyte (PMNL), both intra– and extracellularly.

Ropivacaine, a new long–acting amino–amide local anaesthetic agent, bupivacaine, lidocaine, mepivacaine and prilocaine in concentrations 1–5 μg–ml‐1up to 500–1000 μg–ml‐1were compared to an untreated control. PMNLs were isolated from heparinized blood (healthy adult volunteers). Cells were incubated with the various local anaesthetics (37C, 30 min), then placed in a Biolumat (luminol–amplified chemiluminescence) and stimulated by formyl–methionyl–leucyl–phenylalanine (FMLP), phorbol myristate acetate (PMA) or ionomycin. Horseradish peroxidase (HRP) was added to discriminate between an intra– or extracellular response.

In general, a decrease in chemiluminescence–response was seen with higher concentrations (500–1000 μg–ml‐1) of the various local anaesthetics. Lidocaine showed a decrease even at lower concentrations. A marked increase in intracellular response for prilocaine 1000 μg–ml‐1(3894 μmol–1‐1) accompanied by a reduction in extracellular response, using FMLP HRP as a stimuli, was noted. Ropivacaine 1000 μg ml‐1(3216 umol–1‐1) showed a decrease both intra– and extracellularly that was similar to, and even somewhat more pronounced than lidocaine 1000 μg–ml‐1(3692 μmol'l‐1), when using PMA with or without HRP as the stimuli.
Response of pial vessel diameter and regional cerebral blood flow to CO2 during midazolam administration in cats
Authors: KUMANO H. , FURUYA H. , YOMOSA H. , NAGAHATA T. , OKUDA T. , SAKAKI T.
Published: January 2009

Midazolam has been demonstrated to preserve the response of cerebral blood flow to CO2. However, the responsiveness of cerebral vessels or microcirculation during midazolam administration related to alteration of cerebral blood flow has not been explored. The purpose of this study was to examine the effects of midazolam on cerebral microcirculation. Nine cats were paralyzed and mechanically ventilated under nitrous oxide/oxygen anaesthesia. Using the closed cranial window technique and laser Doppler flowmetry, diameter of pial vessels and regional cerebral blood flow (rCBF) were examined on the surface of the cerebral cortex which was perfused by the middle cerebral artery. Before midazolam administration, haemodynamic variables, blood gases, rCBF, and diameter of pial vessels were determined as a control under normocapnia, hypocapnia, and hypercapnia conditions. After midazolam administration, given initially at 0.8 mg kg‐1·min‐1 for 10 min and subsequently at 0.04 mg kg‐1 min“1 (total dose 10 mg kg‐1‘), the same variables were again analyzed. With regard to CO2 responsiveness, an 8.85% increase in rCBF was demonstrated for a Paco2 elevation of 1 kPa before midazolam administration, compared with a 7.47% increase after midazolam administration. With regard to the correlation between C02 response and vessel diameter, arterioles less than 50 μm in diameter were more sensitive than those more than 50 μm in diameter, although there were no significant differences before or after midazolam administration. We conclude that CO2 responsiveness is preserved in terms of rCBF and vessel diameter after high doses of midazolam (10 mg·kg‐1) in cats.
Risus sardonicus and laughing gas – when nitrous oxide lost its innocence
Authors: KRISTENSEN H. SUND , BERTHELSEN P. G.
Published: January 2009

Relief from pain is purchased always at a price. The price in both morbidity and mortality does not greatly differ whatever the agent or agents used. Men occasionally stumble over the truth, but most of them pick themselves up and hurry off as if nothing had happened. Winston Churchill. R. M. Waters 1994
Intradermal anaesthesia: comparison of several compounds
Authors: PRIEN TH.
Published: January 2009

Objective: To compare the efficacy of different local anaesthetics to produce intradermal anaesthesia for venous cannulation and the discomfort associated with skin infiltration.

Measurements: A visual analog scale (VAS) for pain (0 = no pain/10 = most pain imaginable) was used to assess pain elicited by raising the skin wheal and inserting the cannula.

Main results: With regard to analgesic potency all five local anaesthetics were comparable (mean VAS–score 1.7–2.09) and effective when compared to 0.9% saline (mean VAS–score 4.2; P < 0.001). Infiltration pain was least with mepivacaine–1 (mean VAS–score 1.0; P < 0.001) and highest with procaine (mean VAS score 2.7; P < 0.001).
A new hybrid anaesthetic circuit for a low–flow rebreathing technique
Authors: MENTELL O. , REVENÄS B. , JONSSON L.
Published: January 2009

The coaxial Mapleson D (Bain) circuit is close to an ideal anaesthetic breathing circuit but it requires a high fresh gas flow (VF). The CO2 absorber circuit can be used with a low VF but the patient end is clumsy and hyperventilation is common unless a small tidal volume (VT) and a low respiratory frequency (f) is used. To overcome these problems a new hybrid anaesthetic circuit has been constructed. The new system has a slender coaxial patient end, connected to a Y–piece and a CO2 absorber circuit with unidirectional valves. The VF supply runs inside the coaxial tube to the patient end, similar to the Bain circuit. The new circuit was tested with simulated controlled ventilation in a lung model and compared to an absorber circuit, an absorber circuit with an added 300 ml dead space (VD) and a Bain circuit. The fraction of end tidal CO2 (FECO2) was measured as a function of VF With VF 1 1 min‐1, VT 10 ml kg‐1 and f 12 breaths min‐1 a simulated 70 kg patient had an FECO2 of 4.8% and a 40 kg patient 5.5% with VF 2 1–min‐1. At zero VFthe the new system was equal to an absorber circuit with 300 ml VD. With increasing VF the FECO2 in the new circuit decrease towards the absorber circuit values. The new system combines the benefits of the Bain circuit with those of a low flow CO2 absorber circuit and offers flexibility in the choice of combinations of VD, f and VF.
Lignocaine–induced convulsion does not induce c–fos protein (c–Fos) in rat hippocampus
Authors: NAKAO S. , KURATA J. , ARAI T. , MURAKAWA M. , ADACHI T. , AVRAMOV M. N. , MORI K. , YASUHARA O. , TOOYAMA I. , KIMURA H.
Published: January 2009

Recent studies have shown that proto–oncogene c–fos mRNA is induced in the central nervous system by a variety of stimuli including generalised convulsions. In this study, the expression of c–fos protein (c–Fos) following lignocaine–induced convulsions was examined and compared with that following convulsions induced by non–anesthetic convulsants, such as pentylenetetrazol, kainic acid and electroconvulsive shocks, in rat brain.

Administration of 120 mg kg‐1 lignocaine by the intraperitoneal route induced generalised convulsions in all rats examined within 10 min. C–Fos was markedly induced in the piriform cortex and amygdala, and slightly induced in the neocortex and thalamus, while no c–Fos expression was observed in the hippocampus. In contrast, c–Fos expression following generalised convulsions induced by non–anaesthetic convulsants was very marked in the hippocampal region, piriform cortex and amygdala, and extended to the thalamus and neocortex.

These results contradict those of previously reported local cerebral metabolic studies using 2–deoxyglucose as a metabolic marker, and suggest that lignocaine–induced convulsions, unlike those induced by non–anaesthetic convulsants, may not cause severe sequelae (plastic changes) in the hippocampus.
The agreement between adductor pollicis mechanomyogram and first dorsal interosseous electromyogram
Authors: ENGBÆK J. , ROED J. , HANGAARD N. , VIBY–MOGENSEN J.
Published: January 2009

The agreement between evoked adductor pollicis mechanomyogram and first dorsal interosseous evoked electromyogram (EMG) was evaluated during a pharmacodynamic study of rocuronium and vecuronium. In the first place the effective doses of rocuronium producing 50% and 90% block (ED50 and ED90, respectively) were established in 32 neurolept anaesthetized patients from the adductor pollicis mechanomyogram and the first dorsal interosseous EMG area and amplitude. Secondly, limits of agreement between the two methods were evaluated from the mean difference between methods 2 s.d. in 20 patients during onset of block following 2 × ED90 of rocuronium and vecuronium, and during recovery from the last supplementary dose of 1/2 × ED90. Limits of agreement show how much the EMG may be above or below the mechanomyogram. No differences were found between mechanomyographical and EMG based ED50 (0.20 mg kg‐1) and ED90 (0.30–0.32 mg kg‐1), respectively. The first EMG train–of–four (TOF) response overestimated block at 25% recovery and underestimated block at 75% and 90% recovery by only 3–7%. Limits of agreement suggested that the EMG may be 7–8% above or below the mechanomyogram during onset compared to 12–17% during recovery. The EMG TOF ratio lagged behind that of the mechanomyogram by 0.05 at TOF ratios below 0.50. No difference was found between methods at a TOF ratio of 0.75. Limits of agreement indicated that the EMG TOF ratio may be 0.12–0.15 above or below that of the mechanomyogram. Agreement between the amplitude and the area of the EMG were better than between the mechanomyogram and the EMG. Evaluation of the time courses of action showed that rocuronium had a faster onset of action than vecuronium (1.8 min compared to 2.8 min) while duration of action and reversal were similar. In conclusion, the first dorsal interosseous EMG amplitude and area can be used to assess rocuronium and vecuronium block.
Respiratory and haemodynamic effects of conventional volume controlled PEEP ventilation, pressure regulated volume controlled ventilation and low frequency positive pressure ventilation with extracorporeal carbon dioxide removal in pigs with acute ARDS
Authors: KESECIOGLU J. , TELCI L. , ESEN F. , AKPIR K. , TÜTÜNCÜ A. S. , DENKEL T. , ERDMANN W. , LACHMANN B.
Published: January 2009

The purpose of this study was to evaluate whether any benefit of low frequency positive pressure ventilation with extracorporeal carbon dioxide removal (LFPPV–ECCO2R) existed over either volume controlled ventilation (VCV) with measured best–PEEP or pressure regulated volume controlled ventilation (PRVCV) with an inspiration/expiration (I/E) ratio of 4:1, with respect to arterial oxygenation, lung mechanics and haemodynamics, in acute respiratory failure.

Fifteen adult pigs were used for the study. Respiratory failure was induced by surfactant depletion by repeated lung lavage. The different therapeutic approaches were applied randomly to each pig for 1 h. Measurements of gas exchange, airway pressures and haemodynamics were performed during ventilatory and haemodynamic steady state. Paco2 was kept constant in all modes.

At almost similar total–PEEP, Pao2 values were significantly higher with LFPPV–ECCO2R comared to VCV with best–PEEP. Peak inspiratory pressure (PIP) and intrapulmonary pressure amplitude defined as the difference between PIP and total–PEEP were significantly lower with PRVCV and LFPPV–ECCO2R compared to VCV with best–PEEP. There was no significant difference between the modes concerning cardiocircu–latory parameters.

PRVCV with I/E ratio of 4:1 and LFPPV–ECCO2R proved to be better modes to achieve better gas exchange and lower PIP at lower intrapulmonary pressure amplitudes. It is concluded that PRVCV is an adequate form of treatment under these experimental conditions imitating acute respiratory failure, without necessitating other invasive measures.
Identification of human plasma cholinesterase variants using molecular biological techniques
Authors: Jensen F. S. , Schwartz M. , Viby‐Mogensen J.
Published: January 2009

Genetic variation is one of several factors determining the level and quality of plasma cholinesterase activity (butyrylcholinesterase, BChE). The many genetic variants known today, and the resulting large number of genotypes and phenotypes, have complicated the problem of identifying individual BChE genotypes and phenotypes on the basis of enzymatic analyses alone.

Modern molecular biological techniques have, however, permitted the development of diagnostic tests which allow BChE variants to be identified at the DNA level. Today, at least 20 genetic variants have been identified in this way.

This review is an introduction to the principles of molecular biology used to identify the variants forms of the BCHE gene.
Identification of human plasma cholinesterase variants in 6,688 individuals using biochemical analysis
Authors: Jensen F. S. , Skovgaard L. T. , Viby‐Mogensen J.
Published: January 2009

In 1973, a Cholinesterase Research Unit was established in Denmark (DCRU). The primary aim was to provide a central sendee for determining genotypes and activity of plasma cholinesterase (BChE) in patients showing abnormal response after succinylcholine. The purpose of the present study was, on the basis of 20 years experience with this Unit, to establish accurate reference intervals for BChE activity and inhibition values for the different genotypes of BChE. Also we wanted to evaluate the influence of age and sex on the BChE activity in genotypically normal patients. Plasma cholinesterase activity was measured using benzoylcholine as substrate. The genetic variations of the enzyme were identified using differential inhibitors, i.e: Dibucaine, Sodium Fluoride, Succinylcholine, Urea and Ro‐2–0683. We investigated 6,688 patients. The reference values for the 13 genotypes represented agree with previous findings. In genotypically normal patients, no age or sex differences were found in BChE activity in children below the age of 10 years. From the age of 10 years the activity decreased significantly in both males and females, the activity in females being significantly lower than in males. In females the activity was lowest in the age group 30–40 years, returning to prepuberty level at about 60 years of age. In males the activity decreased slightly up to 50–60 years of age. Hereafter the activity was stable or tended to increase slightly. Most genotypes could be recognized using the results of the different inhibition studies. We found the inhibitors Dibucaine, Sodium fluoride, Urea and Ro‐2–0683 most helpful, whereas succinylcholine was of less value. We conclude that though most genotypes can be recognized biochemically, several variants with heterozygous occurrence of an abnormal and a usual gene are still very difficult or impossible to differentiate in this way. This, together with the increasing number of possible genotypes, have increased the need for tests based on DNA analyses.
Interstitial fluid accumulation does not influence oxygen uptake in the rabbit small intestine
Authors: ØStgaard G. , Reed R. K.
Published: January 2009

Crystalloid resuscitation increases interstitial fluid volume. Intestinal ischemia and impaired barrier function may contribute to the precipitation of multiple organ failure. Accordingly, the intestine was chosen as target organ to test whether interstitial oedema impairs oxygen extraction by the tissue.

The portal vein in anaesthetized rabbits was partially obstructed for 30 min along with an intravenous infusion of 0.9% saline 60–90 ml kg‐1 (oedema group, n = 7). Total water content of the small intestine increased from 3.4 ml g‐1 dry weight in control (n = 8) to 3.9 ml g‐1 in the oedema group (P= 0.049). Small intestinal O2 uptake was calculated from the arteriovenous O2 content and electromagnetic flow measurements in the superior mesenteric artery. Mesenteric flow was reduced stepwise by a snare occluder around the artery. Intestinal oxygen‐ation was monitored indirectly as well, by means of mesenteric venous lactate, arterial base excess and by mucosal pH (pHi) assessed tonometrically.

The oxygen extraction ratios were similar in the oedema and control group at similar oxygen supplies. After a 45 min flow reduction to 15% of baseline mesenteric venous lactate and pHi did not differ between the groups. pH; averaged 7.31 and fell to 6.74. Below an intestinal O2 uptake of 2.5 ml min‐1, pHi correlated somewhat better with O2 uptake (r=0.66) than did arterial base excess (r=0.50).

The results indicate that acute elevation of extracellular volume to the extent in the present study, does not impede oxygen uptake in the gut.
Effects of hypothermia on the elimination of ethanol, diazepam and oxazepam in rat liver slice incubations
Authors: Mortensen B. , Dale O.
Published: January 2009

The elimination of ethanol, diazepam and oxazepam which are metabolised by different enzymes, has been studied for 30, 60, 90 and 120 min at 37, 27, 17 and 7d̀C in rat liver slice incubations. Ethanol elimination followed zero‐order kinetics at all temperatures, while the benzodiazepines consistently displayed first‐order kinetics. No sign of phasetransition was observed in the respective Arrhenius‐plots. Ethanol elimination was more temperature dependent than the elimination of diazepam, while the elimination of oxazepam was little influenced by temperature. This is shown by the temperature ratios (Q10) and energies of activation (Ea) of 1.76, 1.56, 1.24 and 40.5, 31.9, 15.2 for ethanol, diazepam and oxazepam, respectively. This means that ethanol, diazepam and oxazepam elimination was reduced by 25, 22 and 14%, respectively, for each 10d̀C of temperature reduction, which is considerably lower than the commonly observed 50% reduction of enzyme activity. We conclude that observations made for one drug on temperature dependent elimination may not apply to other drugs.