bluuebunny/crossref_metadata_2025 huggingface dataset:
Aortic surgery: effect of clonidine on intraoperative catecholaminergic and circulatory stability
Authors: Quintin L. , Bonnet F. , Macquin I. , Szekely B. , Becquemin J. P. , Ghignone M.
Published: January 2009

Twenty‐eight patients presenting for aortic surgery were randomly assigned in a double‐blind, placebo‐controlled protocol to receive placebo (n=14) or clonidine (4.7 ± 1.2 μg · kg‐1po; n=14), in addition to flunitrazepam 120 min before induction of anesthesia. Plasma catecholamines (CA) and hemodynamic variables were determined at 7 stages during surgery. In the placebo group, plasma epinephrine (E) and norepinephrine (NE) had risen twofold at skin closure compared to baseline (E: from 109 ± 51 pg p ml‐1to 294 ± 161 pg · ml‐1; NE: from 658 ± 226 to 1150 ± 494 pg · ml‐1). Plasma CA were significantly lower in the clonidine group (P<0.001 and 0.01 vs placebo for NE and E respectively). In both groups, similar directional changes were observed for the circulatory variables, upon aortic clamping and declamping. In the clonidine group, however, mean arterial pressure was lower at most stages (P<0.05 vs placebo); moreover, stroke volume index was greater in the clonidine group (P>0.05) upon declamping. This improved stability in the clonidine group was achieved with a halving in the number of anesthetic/circulatory interventions (P>0.05 vs placebo). Provided intravascular volume is adequate, clonidine suppresses the increase in plasma catecholamines induced by aortic surgery and improves circulatory stability, with a reduced number of anesthetic/ circulatory adjustments.
Measurement of cardiac output by the thermodilution method during left thoracotomy in the lateral position in the dog
Authors: Landais A. , Morin J. P. , Roche A. , Cornec C. , Sansoy N.
Published: January 2009

The validity of cardiac output measurement by thermodilution in the lateral position during thoracotomy was assessed. Three balloon thermodilution Swan‐Ganz catheters were placed in the pulmonary artery trunk and the right and left pulmonary arteries in 12 mongrel dogs, after left thoracotomy had been performed. Cardiac output was measured simultaneously from two of the three sites. The cardiac output measurements show no significant difference related to the location of the cathether extremities: the mean cardiac index was found to be 2.164 ± 0.448 1/min/m2 from the pulmonary artery trunk, 2.127 ± 0.404 1/min/m2 from the left branch and 2.116 ± 0.421 1/min/m2 from the right branch. It is concluded that the measurement of cardiac output during left thoracotomy is valid, whether the thermistor is situated in the pulmonary artery trunk or in a main branch to either the dependent or non‐dependent lung.
Prilocaine‐induced methemoglobinemia evidenced by pulse oximetry
Authors: Bardoczky G. I. , Wathieu M. , D'Hollander A.
Published: January 2009

Methemoglobinemia was suspected in a healthy 19‐year‐old woman, when the pulse oximeter reading (Spo2) was 88% after a plexus brachialis block with 550 mg (35 ml, 1.5%) prilocaine. The patient was receiving 50% oxygen, and the Pao2 was 48.6 kPa (365 mmHg). After start of methylene blue treatment, with a total dose of 1 mg/kg, the Spo2 showed a gradual increase. This case report emphasises the potential advantage of arterial oxygen saturation monitoring with a pulse oximeter, but also the importance of the correct interpretation of the Spo2 reading.
Spondylitis without epidural abscess formation following short‐term use of an epidural catheter
Authors: Lynch J. , Zech D.
Published: January 2009

A 42‐year‐old patient had undergone total hip replacement for aseptic femoral head necrosis 9 years previously. He now presented with loosening of the prosthesis and pseudoarthrosis sustained following a femoral shaft fracture 7 months earlier. A total hip replacement was carried out in general anaesthesia combined with an epidural catheter. The epidural catheter was removed on the third postoperative day, after which the patient complained of persistent lumbar pain which was associated with meningismus, fever, leucocytosis and a raised erythrocyte sedimentation rate. In spite of intensive laboratory and radiological investigation, 15 weeks elapsed before a radiological diagnosis of spondylitis of L 1 and L2 could be made. Aspiration biopsy of the L1/L2 disc space yielded a growth of Pseudomonas aeruginosa. Antibiotic therapy was begun immediately but could not prevent spread of infection to the adjacent disc‐space T12/L1 and the vertebral body T12. The patient made a slow recovery and was discharged in a satisfactory condition wearing a lumbar brace some 9 months after the operation. No evidence of epidural abscess formation was found at any stage and no direct connection between the use of the epidural catheter and spondylitis could be established.
Constant‐flow ventilation during experimental left ventricular failure
Authors: Hachenberg T. , Meyer J. , SielenkÄmper A. , Knichwitz G. , Haberecht H. , GÜlker H. , Wendt M.
Published: January 2009

The efficacy of constant‐flow ventilation (CFV) was investigated in dogs with normal heart function (control phase, n = 8) and after development of left ventricular failure (LVF phase, n = 8). Heated, humidified and oxygen‐enriched air (inspired oxygen fraction (Fio2)=0.4) was continuously delivered via two catheters positioned within each mainstem bronchus at two flow rates (1.2 and 1.6 1/kg/min). Conventional mechanical ventilation (CMV) with positive end‐expiratory pressure (PEEP) of 0.5 kPa was used as reference ventilation. During control, neither CMV with PEEP nor CFV revealed severe impairment of cardiopulmonary performance. Alveolo‐arterial Po2 difference (P(A‐a)o2) increased significantly during CFV1.2 and CFV1.6, indicating a higher degree of ventilation‐perfusion (VA/Q) inhomogeneity. Acute left ventricular failure (LVF) was induced by proximal occlusion of the left anterior descending (LAD) coronary artery. Cardiac output (CO), maximum velocity of pressure development (dP/dtmax and mixed venous Po2 decreased (p0.05), whereas left ventricular end‐diastolic pressure (LVEDP) and pulmonary capillary wedge pressure (PCWP) increased (P0.05), Extravascular lung water (EVLW), as determined by thermal‐dye technique, increased from 10.1 ml/kg to 20.9 ml/kg (P0.01). Oxygenation, but not Co2 elimination, deteriorated in the LVF phase. There were no haemodynamic differences between CMV with PEEP and CFV1.2, but cardiopulmonary performance deteriorated with CFV1.6. Gas exchange was significantly more impaired during CFV1.2 and CFV1.6 due to increased VA/Q mismatching. However, there were no significant differences for P(A‐a)o2 values between CFVContro, and CFVLVp This may be due to preferential ventilation of basal lung units with unchanged regional perfusion and redistribution of alveolar oedema towards non‐dependent parts of the lung. CFV maintains sufficient gas exchange in dogs with acute ischaemic cardiac failure. CMV with PEEP is more effective in achieving oxygenation and Co2 elimination with fewer consequences for cardiopulmonary performance.
Lung lavage and surfactant replacement for hydrochloric acid aspiration in rabbits
Authors: KOBAYASHI T. , GANZUKA M. , TANIGUCHI J. , NITTA K. , MURAKAMI S.
Published: January 2009

Hydrochloric acid (0.1 N, 5.0 m1.kg‐1 in total) was administered intratracheally to 28 adult rabbits anesthetized with pentobarbital and mechanically ventilated with pure oxygen. When the Pao2 decreased to 14.1 ± 2.8 kPa (mean±s.d.), the Paco2 increased to 8.9±2.5 kPa, and the minute ventilation (VE) decreased to 51 ± 8% of the baseline value, animals were divided into 4 groups. The deteriorated values did not improve in the non‐treated (control) animals, whereas the animals treated with lung lavage and surfactant replacement showed a significant increase in Paco2, to 35.1 ± 12.2 kPa, and maintained lower Paco2, and larger VE, than the controls. These parametea showed no significant improvement with surfactant replacement alone, and deteriorated further with lung lavage alone. The minimum surface tension (γmin) of the edema fluid that accumulated in the airways after acid administration was 22.5 ± 1.7 mN · m‐1, and was not lowered by adding surfactant preparation (10 mg.ml‐1) whose original γmin was < 2 mN · m‐1. We concluded that surfactant inhibition by edema fluid was a cause of respiratory failure, and that lung lavage followed by surfactant replacement might be of therapeutic value for acid aspiration.
Comparison of anaesthesia ventilators using a lung model
Authors: JOHNSON A. , BENGTSSON M.
Published: January 2009

The ventilatory performance of six anaesthesia ventilators (Alphavent® Drägerwerh; MCM 801 Ventilator® Dameca; Ohmeda 7000 Ventilator® and Ohmeda 7800 Ventilator® Ohmeda; Servo Ventilator 900 D® and Ventilator 710® Siemens‐Elema) was tested in a lung model and compared with the ventilatory performance of the old Engström 300® (Gambro Engström). The lung model consisted of one tracheal tube, two bronchial tubes which could be partially occluded, and two lungs (glass jars filled with water to a suitable compliance). Dialled (set) minute volume was compared to recorded minute volume. Gas distribution between obstructed and non‐obstructed lung was calculated. All ventilators had a linear relationship between dialled and measured volume. Only the Servo Ventilator 900 D produced a gas distribution which was as good as, or better than that produced by the Engström 300.
Postoperative emesis after pediatric strabismus surgery: the effect of dixyrazine compared to droperidol
Authors: LARSSON S. , JONMARKER C.
Published: January 2009

Sixty‐one children, ASA physical status I, aged 2–14 years, admitted for strabismus surgery were studied. All were premedicated with diazepam and atropin rectally. Anesthesia was induced with thiopental or with halothane on a facemask, and succinylcholine was given to facilitate tracheal intubation. Anesthesia was maintained with halothane and nitrous oxide. Each child was randomly assigned to receive either no antiemetic prophylaxis (control), droperidol O.075 mg/kg, or dixyrazine 0.25 mg/kg. The drugs were injected intravenously at the end of surgery. The incidence of vomiting during the following 24 h was 65% in the control group, 48% in the droperidol group, and 25% in the dixyrazine group (P<0.05 as compared to the control group). Four hours after the operation, six children in the droperidol group and none in the dixyrazine group (P< 0.05) were difficult to arouse. It is concluded that dixyrazine reduces the incidence of postoperative vomiting without causing heavy sedation.
Predictable Paco2, with two different flow settings using the Mapleson D system
Authors: JONSSON L. O.
Published: January 2009

Two different settings of fresh gas flow (FG) and minute ventilation (E) used with the coaxial Mapleson D system (Bain), were evaluated in 59 adults (ASA I‐III) during controlled ventilation and different types of surgical procedures. The two flow settings (alternatives A and B) were of FG 75 and 110 ml · min‐1. kg‐1 and E, of 150 and 175 ml · min‐1 kg‐1, aiming to generate normocapnea and mild hypocapnea, respectively. The Paco2 obtained with alternative A was 5.5 ± 0.5 kPa (mean ± s.d.), with 92% of the patients within the range 4.7–6.1 kPa. With alternative B, the Paco2 was 4.4 ± 0.5 kPa, with 82% of the patients within the range 3.5–4.9 kPa. It is concluded that these two flow regimes are suitable for clinical use when either normocapnea or mild hypocapnea is desired.
Intra‐operative epidural blockade with local anaesthetics and postoperative protein breakdown associated with hip surgery in elderly patients
Authors: Carli F. , Emery P. W.
Published: January 2009

The effect of epidural anaesthesia of limited duration on postoperative protein breakdown was studied in elderly patients undergoing hip arthroplasty. Two groups of six patients each were studied. One group with halothane (C) and one with an epidural block, T8–S4, (E) as part of their general anaesthetic for surgery. The urinary excretion of urea nitrogen and 3‐methylhistidine (3‐MeH), an indicator of muscle protein breakdown, increased significantly in both groups after surgery, by the same amount (P< 0.05). The total concentration of plasma and muscle aminoacids decreased after surgery in both groups. Muscle glutamine was decreased by 50% after surgery on the fourth postoperative day in both groups (P<0.05). Therefore epidural anaesthesia, limited to the period of surgery, did not attenuate the loss of body proteins which occurred during the postoperative period.
Effects of halothane on the efflux of [3H]D asprtate from rat brain slices
Authors: Arai T. , Hatano Y. , Mori K.
Published: January 2009

The in vitro effects of halothane on the potassium‐stimulation‐induced efflux of [3H]D‐aspartate in rat cerebral cortex slices were studied. The slices were initially incubated with Krebs‐Ringer's solution containing [3H]D‐aspartate, a putative excitatory transmitter. The slices were then stimulated with high concentrations of K+ in the presence and absence of halothane, and the efflux was measured using a scintillation counter. Halothane, 1% and 2%, had little effect on the potassium‐stimulation‐induced efflux, but that of 4 and 8% increased the efflux significantly. The spontaneous efflux was unaffected by all concentrations of halothane studied. The control study of pentobarbital, in the concentration of 0.05 to 1.00 mmol/1, reduced the efflux in a dose‐related manner. These findings indicate that the release of an excitatory transmitter, aspartate, may not be involved in the mechanism of halothane anaesthesia.
Vagal and sympathetic activity during spinal analgesia
Authors: Cook P. R. , Malmqvist L‐A. , Bengtsson M. , Tryggvason B. , Löfström J. B.
Published: January 2009

Indices of vagal and sympathetic activity were studied in 30 elderly males, to elucidate their possible roles in causing hypotension during spinal analgesia. The technique of spinal analgesia and the regimen of intravenous fluids were standardised. An index of vagal activity was derived from the degree of heart rate variation (successive RR interval change) on ECG recordings. Sympathetic activity was evaluated by changes in the skin conductance (SCR) of 15 patients. Analgesia to pinprick reached a median dermatome level of T5–6 (range T2–T10) by 15 min. Hypotension was correlated with the level of analgesia, and was more likely when spinal analgesia was higher than T5. There was no correlation between vagal activity and the degree of hypotension. The depression of skin conductance responses was not correlated with the degree of hypotension nor with vagal activity. Vagal efferent activity, measured at the heart, does not seem to play a causative role in hypotension occurring during spinal analgesia.
Laboratory evaluation of heat and moisture exchangers. Assessment of the Draft International Standard (ISO/DIS 9360) in practice
Authors: Eckerbom B. , Lindholm C.‐E.
Published: January 2009

A lung model and test method in accordance with the ISO draft standard for evaluation of heat and moisture exchangers (HME's) was designed. The trial period was 24 h. The moisture‐conserving ability of the HME was determined gravimetrically and the temperature performance was calculated from graphs obtained by temperature probes near the two ports of the HME. To determine the reproducibility of the test results, the model was used without an HME and with two HMEs from different manufacturers. The performance values obtained from all three series indicated that the reproducibility of the method was good. The difference between mean inspiration and mean expiration temperatures at the patient port (dTp) provides a useful, simple and reproducible measure of the HMEs' temperature performance. Based on these data, we suggest certain changes in the test procedures outlined in the proposed ISO draft standard.
Cath‐Finder‐TM Catheter Tracking System: a new device for positioning of central venous catheters. Early experience from implantation of brachial portal systems
Authors: Starkhammar H. , Bengtsson M. , Kay D. A.
Published: January 2009

To simplify the implantation procedure of a new brachially implantable venous access system (P.A.S. PortTM, Pharmacia Deltec Inc., St. Paul, MN, USA), the Cath‐FinderTM Catheter Tracking System (Pharmacia Deltec) was evaluated. The Cath‐Finder senses the catheter tip position by utilizing a preconnected sensor wire (guidewire) within a catheter to detect an electromagnetic signal transmitted through the body tissue from a locator wand positioned over an appropriate external landmark. The aim of the study was to evaluate the accuracy of the Cath‐Finder (compared to fluoroscopy) in determining the catheter tip position peroperatively during implantation of P.A.S. PortTM systems in patients with malignant diseases. The accuracy of the Cath‐Finder in assessing the position of the catheter tip was registered in 16 implantation procedures. The tip positions determined with the Cath‐Finder (when projected on the skin) correlated well to fluoroscopy (within 1 cm in eleven patients, 2–3 cm in four patients, and 4 cm in one patient). By using the right 3rd rib parasternally as an external landmark for the locator wand, the Cath‐Finder Catheter Tracking System appears to be an alternative to fluoroscopy peroperatively for accurate placement of central venous catheters in the superior vena cava. However, a postoperative confirmatory x‐ray control is recommended until further experience of the system is available.
No cutaneous histamine release with buprenorphine?
Authors: Girotra S. , Atray R. , Mittal M.
Published: January 2009

Most narcotics cause histamine release, both systemic and cutaneous. Whether buprenorphine causes histamine release is not yet known. We conducted intradermal tests on 11 healthy adults with buprenorphine in dilutions of 1:10000, 1:1000, 1:100 and 1:10 and with 0.9% saline and histamine 10‐3mol/1. The size of dermal reaction was noted after 15 and 30 min. None of the volunteers showed any cutaneous reaction suggestive of histamine release with buprenorphine. The absence of histamine‐releasing activity of buprenorphine may be due to the structure of the drug resulting in its decreased basicity or to the insufficient concentration of the drug achieved at mast cell membrane.
Effects of different plasma substitutes on plasma fibronectin concentrations in patients undergoing abdominal surgery
Authors: Perttilä J. , Salo M. , Peltola O.
Published: January 2009

Plasma fibronectin is important for host defences as an opsonin of the mononuclear phagocyte system (MPS). The effects of three types of plasma substitutes, crystalloid, gelatin and dextran solutions, on plasma fibronectin levels were studied in patients undergoing abdominal surgery in relation to serum total protein and serum C‐reactive protein (CRP) levels. Plasma fibronectin levels decreased during induction of anaesthesia and infusion of an electrolyte solution before infusion of the plasma substitute, and they were further decreased during operation after infusion of plasma substitutes and remained depressed on the first postoperative day in all study groups (P<0.05–0.01). In the crystalloid and dextran groups, plasma fibronectin levels exceeded preoperative levels by the 4th‐5th postoperative day (P<0.05–0.01), but in the gelatin solution group they remained depressed (P<0.01). Serum total protein levels remained lower than preoperative values throughout the study period (P<0.05–0.01), whereas CRP levels were many times higher on days 1 and 4–5 postoperatively in all groups (P<0.01).
Protein binding of prilocaine in human plasma: influence of concentration, pH and temperature
Authors: Bachmann B. , Biscgping J. , Sinning E. , Hempelmann G.
Published: January 2009

Protein binding of prilocaine was investigated in vitro under various conditions of changing pH, temperature and total plasma concentration by means of HPLC with UV‐detection and ultrafiltration. Whereas changes in temperature (25°C‐40°) and pH (pH 5–pH 10) influenced protein binding markedly, rising plasma concentrations up to 16 μg/ml did not affect plasma protein binding significantly. This may be a possible explanation for clinical evidence of low toxicity associated with the use of prilocaine. Discussions concerning protein binding of local anaesthetics should always be based on defined ambient conditions (pH, temperature, concentration).
The influence of body position and differential ventilation on lung dimensions and atelectasis formation in anaesthetized man
Authors: Klingstedt C. , Hedenstierna G. , Lundquist H. , Strandberg A. , Tgkics L. , Brismar B.
Published: January 2009

The effects of body position and anaesthesia with mechanical ventilation on thoracic dimensions and atelectasis formation were studied by means of computerized tomography in 14 patients. Induction of anaesthesia in the supine position reduced the cross‐sectional area for both lungs and caused atelectasis formation in dependent lung regions in 4/5 patients. Conventional ventilation with positive end‐expiratory pressure (PEEP) increased thoracic dimensions and reduced, but did not eliminate, the atelectatic areas. The vertical diameters of both lungs were smaller in the lateral position as compared to the supine position (16.7 vs 10.4 cm in the left lung and 17.3 vs 12.8 cm in the right lung). The lateral positioning also caused a large reduction of the atelectatic area in the non‐dependent lung. Differential ventilation with selective PEEP to the dependent lung eliminated (3/8 patients) or reduced (5/8 patients) dependent lung atelectasis. It can be concluded that lung geometry is altered in the lateral position: the shape of the lung makes the vertical diameter of each lung less in the lateral position, compared to the supine position. The atelectatic areas are mainly located in the dependent lung in the lateral position, and these atelectatic areas could be further reduced by selective PEEP to this lung.
The influence of pancuronium and vecuronium combined with balanced anaesthesia on haemodynamics and myocardial oxygen balance
Authors: Günnicker M. , Pohlen G. , Hess W.
Published: January 2009

The effects of the non‐depolarizing muscle relaxants pancuronium (Pancuronium®) and vecuronium (Norcuron®) (0.1 mg/kg) on myocardial blood flow, myocardial oxygen consumption, myocardial lactate balance, cardiovascular dynamics and electrocardiogram were studied in two groups of eight patients undergoing coronary artery bypass surgery. After induction of anaesthesia with 0.015–0.02 mg/kg flunitrazepam, isoflurane (0.5 vol%) and N2O/O2 (1/1), neuromuscular blockade was induced with pancuronium or vecuronium (0.1 mg/kg) combined with a single dose of 0.005 mg/kg fentanyl. Haemodynamic measurements were performed and the electrocardiogram was recorded before anaesthesia, in steady‐state anaesthesia, after relaxation with pancuronium or vecuronium combined with fentanyl, and after intubation. The haemodynamic data consisted of heart rate, cardiac index, stroke volume index, mean arterial pressure, total peripheral resistance, pulmonary arterial pressure, pulmonary capillary wedge pressure, right atrial pressure, myocardial blood flow, coronary vascular resistance, myocardial oxygen consumption, coronary aterio‐mixed venous content difference, myocardial lactate extraction and rate pressure product. In the vecuronium group, heart rate decreased significantly more (21%) than in the pancuronium group (9%). Therefore myocardial oxygen consumption (48% resp. 35%) and coronary blood flow (31% resp. 18%) decreased more in the vecuronium than in the pancuronium group. The higher metabolic demand in the pancuronium group induced a significantly lower coronary vascular resistance, because the decrease in coronary perfusion pressure was similar in both groups. None of the other haemodynamic parameters differed significantly in either patient group. We did not observe ST‐segment depressions or elevations in the ECG, increases in PCWP or myocardial lactate production. Therefore extended myocardial ischaemia can be excluded in our patients who received pancuronium or vecuronium for neuromuscular blockade.
Local corticosteroid application blocks transmission in normal nociceptive C‐fibres
Authors: Johansson A. , Hao J. , Sjölund B.
Published: January 2009

The effect of a locally applied depot form of a corticosteroid on the electrical properties of nerves was investigated in an experimental model. The segmental transmission in electrically stimulated A‐fibres and in C‐fibres of the plantar nerve in the anaesthetized rat was utilized. A drop of methylprednisolone acetate or vehicle constituent was placed on the dissected plantar nerve proximal to the stimulating electrodes after recording control responses (A‐fibre volley in the sciatic nerve and C‐fibre evoked reflex discharge in flexor motoneurons). The corticosteroid was found to suppress the transmission in thin unmyelinated C‐fibres but not in myelinated A‐beta fibres. The effect was found to be due to the corticosteroid per se. The effect was reversed when the corticosteroid was removed, which suggests a direct membrane action.
Hemodynamic effects of interpleural analgesia in pigs
Authors: Strømskag K. E. , Pillgram‐Larsen J. , Reiestad F. , Steen P. A.
Published: January 2009

Six anesthetized pigs received bupivacaine 2 μg/kg with epinephrine 2 1.1g/kg interpleurally while six saline injected animals served as controls. The animals were monitored hemodynamically for 120 min after injection. There were no significant changes in hemodynamic variables in the control group. In the group receiving bupivacaine with epihephrine there was a pattern of increase in mean arterial blood pressure, systemic vascular resistance and mean pulmonary arterial blood pressure after 60 min of observation. There were no other significant changes in pulmonary or systemic hemodynamics or gas exchange as evaluated by blood gases or whole body oxygen consumption. It is speculated that the increased systemic vascular resistance was an effect of the epinephrine added to the anesthetic. Interpleural analgesia may be a safe pain‐relieving method even in slightly hypovolemic individuals.
Changes of blood pressure and cerebral arterio‐venous oxygen content differences (AVDo2) with and without bupivacaine scalp infiltration during craniotomy
Authors: Engberg M. , Melsen N. C. , Herlevsen P. , Haraldsted V. , Cold G. E.
Published: January 2009

In 20 patients subjected to craniotomy for supratentorial cerebral tumours, the effect of scalp infiltration with bupivacaine before incision was evaluated by measuring mean arterial blood pressure (MABP) and cerebral arterio‐venous oxygen content differences (AVDo2) repeatedly during the operation. All patients were given halothane 0.5% anaesthesia. Ten patients were given bupivacaine 0.25% and ten patients were given normal saline for scalp infiltration prior to incision. The study was performed in a double‐blind randomized fashion. Significantly higher values of MABP (P<0.0005) after incision were found in the saline group compared to the bupivacaine group. Significantly lower values of AVDo2 (P<0.0005) after incision were seen in the saline group compared to the bupivacaine group. The results indicate that the increase in MAPB associated with a decrease in AVDo2, suggesting an increase in CBF and cerebral hyperperfusion, is reduced by using bupivacaine scalp infiltration prior to incision.
Repeatability of the acetylene rebreathing method in measuring cardiac output: influence of acetylene concentration
Authors: Nielsen O. Wendelboe , Hansen S. , Christensen P. , Grønlund J.
Published: January 2009

The acetylene rebreathing method is a reliable noninvasive method for estimation of cardiac output. However, the method is not commonly used for clinical purposes. This is due mainly to the fact that acetylene is explosive at concentrations above 2% and that acetylene at concentrations above 0.5% has an unpleasant taste. In the present study we have investigated whether it is possible to reduce the concentration of acetylene to 0.3% in the rebreathing bag without degrading the repeatability of the estimated cardiac output. The problem was elucidated theoretically and experimentally. A theoretical investigation was carried out by producing an acetylene rebreathing curve from a single alveolus lung model. The theoretical study showed that the random noise arising from the gas analyzer gives rise to less than 10% of the total variation of the estimated cardiac output. The results of the experimental study showed that it is possible to reduce the acetylene concentration to 0.3% without decreasing the reproducibility of the acetylene rebreathing method.
Randomized comparison of recovery after propofol‐nitrous oxide versus thiopentone‐isoflurane‐nitrous oxide anaesthesia in patients undergoing ambulatory surgery
Authors: Korttila K. , ÖStman P. , Faure E. , Apfelbaum J. L. , Prunskis J. , Ekdawi M. , Roizen M. F.
Published: January 2009

A randomized, prospective study was performed to compare recovery characteristics in 41 ASA physical status I‐II patients scheduled for ambulatory surgery with either propofol or thiopentone‐isoflurane anaesthesia. Particular attention was focused on the recovery time needed to meet discharge criteria. The propofol group received propofol 2 mg · kg‐1 for induction followed by propofol infusion (6–9 mg · kg‐1 · h‐1) 1 min after intubation. The thiopentone‐isoflurane group received thiopentone 4 mg · kg‐1 for induction followed by isoflurane (0.5–2%) 1 min after endotracheal intubation. Other drugs administered during or after anaesthesia were similar between the groups. The propofol group had significantly (P<0.05) faster clinical recovery than the isoflurane group with respect to times to response to commands, eye opening, orientation, ability to stand and void, tolerance to oral fluids, “home‐readiness”, and recovery of perceptual speed. Patients in the propofol group had significantly less (P<0.05) emesis than the patients given isoflurane. We conclude that in patients undergoing ambulatory surgery propofol infusion is preferable to thiopentoneisoflurane anaesthesia, because it may allow faster discharge home.
Performance evaluation of six heat and moisture exchangers according to the Draft International Standard (ISO/DIS 9360)
Authors: Eckerbom B. , Lindholm C‐E.
Published: January 2009

Six commonly available heat and moisture exchangers (HMEs) were tested according to a draft ISO standard for evaluating these devices (ISO = The International Organization for Standardization). The devices tested were: Pall Ultipor Filter, Mallinckrodt Inline, Siemens Servo 152, Engstrom Edith, Triplus Icor, and Portex Humid Vent 1. The trial period was 24 h and three different ventilator settings were used. For each device the following were determined: humidity‐conserving ability, heat‐conserving ability, resistance to air flow, internal volume, and gas leakage. The water loss (mg/1) at a common ventilator setting (101/min, 20 · min‐1) was as follows: Pall 10.8, Inline 7.5, Servo 9.0, Edith 6.6, Icor 6.2, and for Humid Vent 13.9, as compared to a control value (= no HME) of 24.8. The temperature differences (°C) between exhaled and inhaled gas at the patient port of the HME were: Pall 2.39, Inline 1.31, Servo 1.21, Edith 1.40, Icor 1.12, and for Humid Vent 2.80 as compared to a control value of 5.34. Ventilator settings with higher tidal volumes generally resulted in decreased efficiency. Resistance to air flow was less than 3 hPa · 1‐1 · s‐1 for all devices tested. The internal volumes ranged from 11 to 87 ml. The gas leakage was zero for all devices. Based on our findings the HMEs could be divided into three groups: 1) Icor, Servo, Inline, Edith: very good performance, 2) Pall: good performance for tidal volumes up to about 0.7 1, and 3) Humid Vent 1: acceptable performance for tidal volumes up to 0.5 1.
Postural stability during long‐term treatment of cancer patients with epidural opioids
Authors: Sjøgren P. , Banning A.‐M. , Larsen T. K. , Sørensen C. G. , Jansen E. C.
Published: January 2009

Ten cancer patients treated with stable doses of epidural opioids were tested for postural stability. The postural stability was measured using a quantitative Romberg's test, performed on a computerized force‐plate system. Sway tendencies in the sagittal and the transverse directions were recorded. The postural stability of the patients was compared with values obtained from healthy controls. Comparing the cancer patients with the controls, postural stability in eight out of ten patients was intact. The study suggests that long‐term epidural opioid treatment has little influence on the patient's ability to stand safely.
Septic shock: a goal‐directed therapy using volume loading, dobutamine and/or norepinephrine
Authors: Martin C. , Saux P. , Eon B. , Aknin P. , Gouin F.
Published: January 2009

In patients with septic shock and acute respiratory failure, norepinephrine (NE) alone or in combination with dobutamine was used. The aim of therapy was to obtain or maintain Cl ≥ 4.5 1 · min‐1· m‐2, SVR ≥ 700–800 dyn · s · cm‐5and oxygen delivery (Do2) ≥ 550 ml · min‐1· m‐2. Twenty‐three patients (58 ± 3 years) were studied. Initially patients were given intravenous fluid resuscitation to obtain optimal cardiac filling pressures. Eleven patients were considered to be in hyperdynamic septic shock (cardiac index (CI) > 4.5 1. min‐1· m‐2, SVR ≤ 600 dyn · s · cm‐5and oliguria) and were given NE as a single agent (0.9 ± 0.2 μg kg‐1· min‐1). The other 12 patients had CI < 3.5 1 · min‐1· m‐2and were given a combination of dobutamine (12 ± 0.09 μg · kg‐1· min‐1) and NE (1.1 ± 0.2 μg · kg‐1· min‐1). The latter drug was added since systemic vascular resistance (SVR) was less than 600 and oliguria persisted while on dobutamine. In all patients, during NE infusion SVR was greater than 700 dyn · s · cm‐5, C1 ≥ 4.5 1 · min‐1· m‐2and Do2> 550 ml · min‐1· m‐2. Urine flow was significantly increased during NE infusion, and only four patients remained oliguric. Anion gap and oxygen consumption were not modified. A complete resolution of septic shock was seen in 16 out of 23 patients (70%). Hospital mortality was 56%.
Effects of alkaline buffer administration on survival and myocardial energy metabolism in pigs subjected to ventricular fibrillation and closed chest CPR
Authors: Wiklund L. , Ronquist G. , Stjernström H. , Waldenström A.
Published: January 2009

Nineteen anaesthetized piglets were investigated. After characterization and a stabilization period, ventricular fibrillation was induced by a transthoracic DC shock, after which a 10‐min period of cardiopulmonary resuscitation (CPR) took place. CPR included manual chest compression and mechanical ventilation with pure oxygen. After 1 min of CPR an infusion of alkaline buffer was begun and was completed within 5 min. A total of 50 mmol of one of two different buffer solutions was given, either sodium bicarbonate (n=6) or tris buffer mixture (n=7). These two groups were compared with a third control group (n=6) receiving the same volume of normal saline. After 8 min of CPR all animals were given 0.5 mg adrenaline i.v., and after 10 min DC shocks were used to return the heart to normal sinus rhythm. If this procedure was successful, the heart was rapidly (within 15 s) stopped again by another DC shock. Myocardial biopsies were then taken immediately in all animals. Successful CPR was more frequent in the animals given normal saline or tris buffer mixture and no effect was seen in the group given sodium bicarbonate. Survival was statistically correlated to low myocardial content of creatine phosphate and low base excess values in blood. Such parameters as myocardial content of ATP or ACP (adenylate charge potential) had no direct correlation to survival. Sodium bicarbonate induced significantly higher base excess and Pco2 values, while the tris buffer mixture seemed to have a greater alkalizing effect intracellularly. We consider it probable that the poor results regarding survival after experimental CPR combined with a rapid infusion of sodium bicarbonate were a result of the excessive alkalosis created in combination with the higher resulting Pco2. Indirect evidence was given that a slightly alkaline pH also intracellularly supported critical reactions including ATPases essential for cellular survival.
A new method for studying the ventilatory response in patients
Authors: Johnson A. , Löfström J. B.
Published: January 2009

A method for clinical studies of the ventilatory response to carbon dioxide and to hypoxaemia in patients is described. The main parameters with this method are respiratory frequency, tidal volume, minute volume, timing, and drive. The ventilation of volunteers was not affected while breathing air through the designed apparatus. The response to carbon dioxide and to hypoxaemia in volunteers was reproducible and similar to what has previously been described. Our method proved suitable to test the ventilatory responses in patients with varying degrees of impaired ventilation‐perfusion ratios and thus also in patients with a low Pao2. Our method has a higher accuracy than earlier methods.
Intermittent high frequency ventilation. Clinical evaluation of a new mode of ventilation
Authors: Whitwam J. G. , Chakrabarti M. K. , Cody M. , Edlin S. , Lumley J.
Published: January 2009

In this first clinical study of a new mode of ventilation, called intermittent high frequency ventilation (IHFV), a comparison was made in ten patients after myocardial revascularization, between normal ventilation, high frequency ventilation (HFV) and IHFV at 15, 60, 100 and 160 breaths per min (b.p.m.). During IHFV the ventilation was interrupted for 3 s 7 times per min. The measured mean trapped gas volumes were 219 ml at 60 b.p.m. and 716 ml at 160 b.p.m. At 160 b.p.m. during IHFV, the mean, mean airway pressures, pulmonary artery (PAP) and capillary wedge pressures and the Paco2 were decreased, while the cardiac output increased. When the Paco2 was maintained constant, IHFV also allowed a reduction in the mean peak and mean airway pressures. This new mode of ventilation can prevent sustained increases in the lung volume and provide a reduction in intrapulmonary pressures. It also permits the measurement of the trapped gas volume and end‐tidal CO2 gas concentrations several times a minute for the clinical management of patients during high frequency ventilation.
The effect of removal of cerebrospinal fluid on cephalad spread of spinal analgesia with 0.5% plain bupivacaine
Authors: Jawan B. , Lee J. H.
Published: January 2009

Increased intraabdominal pressure is well known to cause higher cephalad spread of spinal analgesia. The reason for this is believed to be a decrease in the cerebrospinal fluid (CSF) volume. If this mechanism is correct, then the cephalad spread of local anesthetic solutions should also be facilitated when the CSF volume is intentionally reduced without increasing the intraabdominal pressure. Sixty‐six patients without evidence of increased intraabdominal pressure and undergoing urological procedures were randomly allocated to three groups. All received 10 mg 0.5% bupivacaine for spinal anesthesia. In Group I, the anesthetic was injected after free drops of CSF. In Groups II and III, three and five ml were removed, respectively, before injecting bupivacaine. Mean cephalad spread of analgesia 20 min after injection in the three groups was T10.2 2.0, T9.4 1.8 and T7.0 2.1, respectively. When CSF was reduced by 5 ml, the level of spread not only showed a statistically significant difference from that of the control group, but also from that of Group II (P< 0.05). Our results show that higher cephalad spread of spinal anesthetic is possible by reducing the CSF volume without evidence of increased intraabdominal pressure.
Disturbances in renal cortical perfusion with reference to the microsphere technique
Authors: Sanding R. , Feuk U. , Modig J.
Published: January 2009

The microsphere technique for studying renal blood flow is based on injection of a small volume containing radioactively labelled microspheres into the left atrium, left ventricle or possibly the root of the aorta. In the present methodological study, superficial renal cortical blood flow and tissue oxygenation were measured in anaesthetized pigs by laser Doppler flowmetry and by oxygen surface electrode technique. Rapid and profound transient decreases in superficial renal cortical blood flow and tissue oxygenation were found after injection of small volumes of plasma and saline into the left atrium. This response was present also when solutions without microspheres were injected. The reaction was not abolished by careful adjustment of the injectate temperature. When the rapid onset of flow reduction is related to the estimated time of delivery of the bolus with microspheres, the validity of regional blood flow measurements using the microsphere technique within the superficial renal cortex must be seriously questioned.
Local cerebral blood flow in spontaneously breathing rats subjected to graded isobaric hypoxia
Authors: Dahlgren N.
Published: January 2009

Local cerebral blood flow (1‐CBF) was measured with an autoradiographic technique in spontaneously breathing rats exposed to air or gas mixtures of O2 and N2, giving inspired oxygen fractions (Fio2) ranging from 0.21 to 0.07. The arterial O2 tension (Pao2) changed from 10.9 0.3 (Fio2 0.21) to 3.9 kPa (Fio2 0.07) (82 2 to 29 mmHg). Hypoxia caused hyperventilation, and the arterial CO2 tension (Paco2) fell from 5.21 0.05 kPa (Fio2 0.21) to 3.27 kPa (Fio2 0.07) (39.1 0.4 to 24.5 mmHg). The hyperventilatory response was markedly augmented when changing Fio2 from 0.13 to 0.11, causing a fall in Paco2 of 0.75 kPa and a shift in arterial pH from 7.45 0.01 (Fio2 0.13) to 7.54 0.01 (Fio2 0.11). The 1‐CBF response to hypoxia was found to be biphasic for all the observed regions. At Fio2 0.13, 1‐CBF was measured about 75% above control but at Fio2 0.11, only 30% above control. A further reduction in Fio2 to 0.07 caused a marked increase in 1‐CBF, at least 240% of control; however, the applied CBF technique did not admit quantitation. These results suggest that the mechanisms controlling the cerebrovascular response to hypoxia and changes in arterial CO2 tensions are different. The results also indicate that hyperventilation might be harmful to the patient suffering from acute hypoxia.
Side effects and complications related to interpleural analgesia: an update
Authors: Strømskag K. E. , Minor B. , Steen P. A.
Published: January 2009

Interpleural analgesia has been successfully used for pain relief after cholecystectomy, renal surgery, breast surgery and thoracotomy. Little has been reported about side effects and complications. This article summarizes available information about adverse events collected from the literature. The survey comprises a total of 703 cases. Pneumothorax was the most frequently registered complication followed by signs of systemic toxicity and pleural effusion. Horner's syndrome, pleural infections and catheter rupture have also been reported.
Comparison of methohexital and pentobarbital for premedication in children
Authors: Christensen P. A. , Balslev T. , Hasselstrom L.
Published: January 2009

Thirty children scheduled for elective orchiopexy or herniotomy were consecutively assigned at random to premedication with methohexital 80 mg/ml, 20 mg/kg rectally, 15 min before transportation to the operating room, or pentobarbital 28 mg/ml, 7 mg/kg rectally, 45 min before transportation. The quality of premedication was recorded at induction with halothane 1–2% and 60% N2O in O2 by mask. All patients received a caudal injection of bupivacaine 1.9 mg/ml, 1.25 ml/kg before surgery. Following completion of anaesthesia, the postoperative wake‐up time and the duration of stay in the post‐operative recovery room were recorded. The degree and quality of recovery were assessed using the Aldrete score every 30 min until discharge from the recovery room. The group of children receiving methohexital showed a highly significantly shorter awakening time, and a highly significantly shorter stay in the recovery room compared to the pentobarbital group. The children in both groups had a quiet, easy recovery without significant signs of confusion or agitation, and no difference in quality of recovery could be shown. Emergence delirium or agitation in connection with pentobarbital premedication and a possible relation to postoperative pain is discussed.
The effects of incisional bupivacaine on postoperative narcotic requirements, oxygen saturation and length of stay in the post‐anesthesia care unit
Authors: Partridge B. L. , Stabile B. E.
Published: January 2009

We compared postoperative pain and narcotic requirements, oxygen saturation (Sao2) and length of stay in the post‐anesthesia care unit (PACU) in patients who received 30 ml of either 0.25% bupivacaine (B) or saline placebo (S) infiltrated into the operative incision. Twenty ASA I–III patients undergoing abdominal surgery were studied in a double‐blinded randomized prospective trial. Study and control groups were not different in patient age, procedure, intra‐operative narcotics administered or preoperative Sao2. In the PACU, patients receiving B had significantly lower analog pain scores (6.0 vs 8.3, P=0.02). They had lower respiratory rates (15.6 b/min vs 19.1, P=0.02), required significantly less narcotic (4.5 mg morphine sulphate vs 11.0, P=0.03) and were discharged from the PACU almost an hour sooner than patients receiving S (P = 0.02). Patients receiving B had significantly higher minimum Sao2 than those receiving S (93.3 % vs 89.9, P=0.04). Discharge pain scores, Sao2 and respiratory rates were not significantly different between B and S groups. Finally, mean requirements for narcotics for the first 24 h were reduced by approximately 30% (from 406.9 mg meperidine to 255.5 mg, P=0.006). This study demonstrates that infiltration of a long‐acting local anesthetic lowers initial pain scores and requirement for narcotics in the PACU. The effect can be seen for at least the first 24 h. A lower requirement for postoperative narcotics is accompanished by faster wake‐up, more alert patients, and, most importantly, higher Sao2 and shorter PACU stay. This may have a significant effect on pulmonary morbidity following abdominal operations.
Effects of epidural anesthesia on sympathetic nerve discharge to the skin
Authors: Lundin S. , Kirnö K. , Wallin B. G. , Elam M.
Published: January 2009

Direct intraneural recordings of skin sympathetic activity (SSA) were performed to determine the magnitude of blockade of sympathetic fibers to the lower extremities during epidural anesthesia. Lumbar epidural catheters were inserted in nine volunteers. Multiunit postganglionic sympathetic activity was recorded in a skin fascicle of the peroneal nerve before and after injection of 4 ml of mepivacaine 2% epidurally, followed by an additional 12–16 ml after 5 min. Arousal stimuli such as sudden loud noises and noxious electrical skin stimulation were used to elicit transient sympathetic activation. Epidural anesthesia with upper level of sensory blockade at T4–T8 (n= 7) completely blocked spontaneous SSA and no detectable skin sympathetic activity could be provoked by arousal stimuli later than 14 min after the test dose. Sympathetic blockade was accompanied by marked increases in foot skin blood flow and loss of skin resistance responses to arousal. Epidural anesthesia with sensory blockade up to T10–11 (n= 2) only produced a partial sympathetic blockade. The result shows that epidural anesthesia with sensory blockade at T8 or above is equally as effective as injections of local anesthetics directly at postganglionic nerve fibers or ganglionic blockade in producing a complete sympathetic blockade of intraneurally recorded SSA. This neural blockade was paralleled by skin vasodilatation and a loss of sudomotor responses in the foot.