bluuebunny/crossref_metadata_2025 huggingface dataset:
An evaluation of tests of psychomotor function in assessing recovery following a brief anaesthetic
Authors: Cashman J. N. , Power S. J.
Published: January 2009

This study was designed to evaluate the usefulness of three commonly used tests of psychomotor function and one test of short‐term memory in assessing recovery from a brief nitrous oxide, oxygen and halothane anaesthetic. Twenty‐six female patients undergoing minor gynaecological surgery were allocated to one of three treatment groups depending on premedication (placebo, low dose and high dose). Immediate recovery was most rapid in the placebo group. Both the tests of simple reaction time and picture recall were able to differentiate between the post‐anaesthetic recovery of the high‐dose group and that of the other two groups. Neither component of the letter cancellation test showed a clear difference in recovery pattern. Tests of critical flicker fusion were too unreliable to be of use in clinical decision making. Our results suggest that tests of reaction time and memory were more sensitive than letter cancellation in assessing recovery.
In what respect does high frequency positive pressure ventilation differ from conventional ventilation?
Authors: SJÖSTRAND ULF H.
Published: January 2009

The original rationale for HFPPV was that under certain conditions adequate alveolar ventilation could be achieved with high ventilatory frequencies and small tidal volumes. It was theorized further that increased ventilatory frequencies and low tidal volumes would decrease the airway pressures, barotrauma, and cardiovascular and other systemic consequences seen with conventional mechanical ventilation. The first clinical applications of HFPPV were in bronchoscopy and laryngoscopy for diagnostic and/or therapeutic purposes. Apart from these endoscopic applications, volume‐controlled HFPPV has been compared with conventional ventilation in upper abdominal surgery and coronary artery bypass grafting. The possible advantages of HFPPV over conventional volume‐controlled ventilation in the intensive care setting are still unclear. Provided that the mean lung volumes are similar, oxygenation in acute respiratory failure is similar with both ventilation methods. Although the role of HFPPV in the management of pulmonary diseases still remains to be clarified, it does provide effective ventilation in selected types of patients needing ventilatory support. New modes of pressure‐controlled ventilation have not resolved all clinical problems in severe ARDS and/or acute respiratory failure. The search for means of optimal ventilatory support with minimal complications must continue, as conventional ventilation does not always offer the best treatment.
Toward improved methods of high frequency ventilation: a study of gas transport mechanisms
Authors: KAMM R. D.
Published: January 2009

Prior studies of gas transport mechanisms are reviewed with the aim of using these results to suggest improvements over current methods of ventilation. These concepts are cast in a simpler framework that more clearly identifies those factors that limit the rate of gas transport under conditions typical of HFV. One simplification introduced simulates the enhancement of molecular diffusion due to the movement of gas back‐and‐forth through regions of varying cross‐sectional area. The region of the lung that currently poses the greatest resistance to gas transport is represented by those airways having diameters in the range of 1.0 to 2.5 mm. This suggests that new efforts should be devoted to better understanding the nature of transport in this zone and to the development of variations in the method of ventilation that have the greatest influence there.
Convective mixing mechanisms in high frequency intermittent jet ventilation
Authors: SCHERER PETER W. , MULLER WILLIAM J. , RAUB JEFFREY B. , HASELTON FREDERICK R.
Published: January 2009

A liquid flow visualization technique was used to identify the location of neutrally buoyant bead clouds injected into airway models during flows simulating high frequency intermittent jet ventilation (HFIJV) in neonatal lungs. The motions of these bead clouds show that the convective or bulk mixing that occurs during HFIJV is made up of two parts; a turbulent convective exchange with the atmosphere caused by the jet in the trachea and a streaming motion along the airways driven by an interaction between the jet and the expansion and contraction of the airways due to their compliance. These convective streaming motions combine with molecular diffusion to produce augmented diffusion which transports O2 and CO2 between the trachea and the peripheral alveoli. Optimizing HFIJV (as well as other forms of HFV) depends on maximizing these airway convective streaming flows which depend on many more lung and fluid mechanical parameters than are necessary to describe conventional mechanical ventilation.
Resonance in the mechanical response of the respiratory system to high frequency jet ventilation
Authors: SMITH B. E. , LIN E. S.
Published: January 2009

Eight normal domestic pigs (Large White breed) of body weights 17 kg to 62 kg were subjected to high frequency jet ventilation (HFJV) at frequencies of 1 to 10 Hz (60–600 breaths/min). Six animals survived the study. The gain response curves and phase shift response curves obtained for these animals indicate that respiratory system resonance can be excited at HFJV frequencies. Post‐mortem examinations of the non‐survivors' lungs suggested pulmonary barotrauma. These findings and their clinical implications are discussed
Gas movement during jet ventilation
Authors: YOUNG JOHN DUNCAN
Published: January 2009

By examining flows in the expiratory limb of a bias flow circuit, it is possible to measure tidal, entrained and spilt volumes during jet ventilation. Using this method on a canine model, tidal volume fell and minute volume rose when the respiratory rate rose from 12 to 200 breaths/min. The changes were compatible with a convective model of gas movement. Entrained volume remained a constant fraction of tidal volume and spilt volume fell as a fraction of jet volume as respiratory rate increased.
Lung surrogates
Authors: NIEDERER PETER F. , BUSH ERIC H. , SCHMID EDITH R. , SPAHN DONAT R.
Published: January 2009

In the development and evaluation of mechanical ventilation on the basis of high‐frequency oscillation, appropriate surrogates of the lung are important, because they allow the measurement and control of various parameters which are not accessible in animal models. Yet, criteria have to be established according to which results obtained with a surrogate may be assessed with a view to extrapolation to humans. Theoretical considerations and impedance measurements are used for this purpose. It is found that for each given frequency a model can be made which exhibits realistic properties. However, no uniformly valid surrogate in the entire frequency range of 10–50 Hz is available at present.
Mobilization of mucus by airway oscillations
Authors: FREITAG L. , KIM C. S. , LONG W. M. , VENEGAS J. , WANNER A.
Published: January 2009

The effects of high frequency asymmetric airway oscillations on mucus clearance were evaluated in excised tracheas of sheep, in an animal model of excessive mucus production, and in patients with bronchiectasis. Asymmetric high frequency ventilation (15 Hz) with expiratory biased flow profiles (expiratory peak‐flow > inspiratory peak‐flow) could move mucus droplets towards the pharynx in rigid and flexible tracheas by gas‐liquid interaction. In rigid tracheas the mucus was transported towards the periphery of the model lung if the oscillations were inspiratory biased. In very collapsible tracheas, however, even inspiratory biased oscillations moved the mucus cephalad. Parameters influencing direction and speed of mucus are airflow profile, peak‐flow, airway compliance and lung resistance. Gamma‐camera studies showed that in anesthetized dogs radiolabeled artificial mucus followed the direction of the bias during high frequency ventilation. In five human volunteers with bronchiectasis and excessive secretions the asymmetric airway oscillations were superimposed during spontaneous breathing using a mouthpiece. Airway wall vibrations following the pressure swings of the oscillator could be observed. During forced expiration inward bulging of the posterior membranes of trachea and bronchi occurred at the negative pressure phase of the oscillations. This event was associated with increased appearance of sputum in the central airways. We conclude that high frequency ventilation with asymmetric flow profiles applied via tube or mouthpiece might be an effective future treatment of mucostasis.
Pathologic features of various ventilatory strategies
Authors: COALSON JACQUELINE J. , DELEMOS ROBERT A.
Published: January 2009

Five pathologic findings have been found to be associated with ventilatory‐induced lung injury in the premature baboon model of hyaline membrane disease. They are: (1) tracheal and major bronchial lesions, (2) small airway changes, (3) inflation pattern aberrations, (4) bronchoalveolar hemorrhage, and (5) air leak problems. The use of immediate high frequency oscillatory ventilation (HFOV) prevents the bronchiolar overdistension (small airway), atelectasis (inflation pattern), and air leak problems. The lesions in the trachea and large bronchi of prematures all show injury secondary to prolonged intubation, but after HFOV the lesions are no worse than those seen in PPV‐treated tracheas. HFOV does increase the incidence of bronchoalveolar hemorrhages, and this lesion plus some of the non‐pulmonary complications will require further investigation.
Volume‐controlled ventilation with superimposed high frequency ventilation during expiration in healthy and surfactant‐depleted pig lungs
Authors: LACHMANN B. , SCHAIRER W. , HAFNER M. , ARMBRUSTER S. , JONSON B.
Published: January 2009

In the healthy and surfactant‐depleted lungs of five pigs the influence of different forms of high frequency ventilation superimposed on conventional mechanical ventilation during the expiratory phase of the ventilatory cycle (SHFVE) on gas exchange and cardiocirculatory parameters was investigated. Subsequently the effects of end‐expiratory flushing (EF), i.e. cleaning the large airways and connecting tubes from the ventilator free from end‐expiratory CO2, with a volume greater than the dead space of the large airways and connecting tubes was investigated. SHFVE and EF resulted in a significant improvement in CO2 elimination in both healthy and surfactant‐depleted lungs. Furthermore, in stiff lungs, at a certain level of oxygenation and CO2 elimination, SHFVE produced the lowest peak and mean airway pressure without any additional depression of cardiocirculatory parameters.
Ventilatory strategy in catastrophic lung disease. Inversed ratio ventilation (IRV) and combined high frequency ventilation (CHFV)
Authors: ANDERSEN JENS B.
Published: January 2009

In 105 patients with well‐defined catastrophic lung disease, in whom conventional settings were unable to maintain life‐sustaining gas exchange, the ventilatory strategy was changed from volume‐controlled ventilation with an inspiratory‐expiratory ratio (I:E) of 1:2 and PEEP of 15–20 cm H2O to pressure‐controlled inverse ratio ventilation with an I:E of 2:1, 3:1 or 4:1 and a set PEEP of 4–8 cm H2O. All patients were ventilated on a Servo 900 B or C ventilator, the primary goal being to decrease the F1O2 below 0.6 and the peak pressure to below 50 cm H2O, while maintaining a Pao2 of 8.00 kPa and a Paco2 within 10% of the upper limit of normal. In 67 patients the intervention was successful and peak pressure could be reduced to a median of 44 cm H2O (range 37–50). Fio2 could be reduced to a median of 0.50 (range 0.40‐0.60). The auto‐PEEP effect of IRV increased to a median of 12 cm H2O (range 7–22). No consistent pattern of change in cardiac output was observed. Sixty patients survived more than 3 weeks and 48 were discharged from hospital. The 38 IRV “failures” were changed to pressure‐controlled ventilation with superimposed high frequency ventilation (CHFV). In 30 cases the Fio2 could be reduced to a median of 0.60 (range 0.50‐0.60) and peak pressures to a median of 50 cm H2O (range 45–60). In 21 patients the Paco2 increased. Auto‐PEEP with CHFV had a median value of 15 cm H2O (range 10–25). Only 12 patients survived more than 3 weeks and only four were discharged. It is concluded that changing the ventilatory strategy to IRV or CHFV can improve gas‐exchange and might alter the outcome in catastrophic lung disease.
Monitoring of physiological parameters during high frequency ventilation (HFV)
Authors: JONSON BJÖRN , LACHMANN BURKHARD , FLETCHER ROGER
Published: January 2009

Non‐biological descriptors such as jet feeding pressure and oscillator stroke volume are often used to describe HFV. This results in confusion and hinders acceptance of HFV. The goal of this paper is to show how physiological parameters which are valid during HFV can be monitored. Airway pressure measured in narrow tubes with high linear flow rates is underestimated. A relevant airway pressure must be measured well below the tracheal tube. Pressure measured higher up should be validated against peripheral pressure measurements. Minute ventilation and expired CO2 concentration can be determined with a ServoVentilator and a CO2 analyzer arranged at its exit port. Minute ventilation and CO2 elimination can thereby be continuously monitored during high frequency jet ventilation or so‐called “combined high frequency jet ventilation” to prevent undetected disturbance of ventilation and perfusion. Physiological dead space can be studied for optimization of ventilatory pattern. The principle of gas analysis at the exit port of the ventilator may be used for FRC determinations with sulfur‐hexafluoride.
Plasma substitution with 3% dextran‐60 in orthopaedic surgery: influence on plasma colloid osmotic pressure, coagulation parameters, immunoglobulins and other plasma constituents
Authors: Bergman A. , Andreen M. , Blombäck M.
Published: January 2009

To study the effects on plasma proteins, blood coagulation and fibrinolysis of dextran‐60, given as plasma volume substitute in a 3% solution, 57 patients were studied preoperatively and for 8 days postoperatively in conjunction with elective orthopaedic surgery. Three groups were formed according to the blood loss during the day of surgery: Group I (n=22) <30%, Group II (n=24) 30–50% and Group III (n=11) > 50% of the estimated blood volume. Dilution to a haemoglobin concentration of 110 g · 1‐1 was intended and erythrocytes transfused accordingly. No platelets were transfused. All patients received similar amounts of crystalloids. Nine patients in Group III received plasma and/or albumin solution for further volume replacement once the maximum dose of dextran (1.5 g · kg‐1) was reached. Dextran‐70 was given on days I and 3 postoperatively for thromboprophylaxis. No patient exhibited clinical signs of thrombosis or embolism. Mean postoperative bleeding times were longer than preoperatively, but still within the normal range in all groups. They were both pre‐ and postoperatively slightly longer in Group III, compared to the other groups, perhaps due to mild haemostatic disorders and/or undisclosed antiphlogistic therapy. Postoperative colloid osmotic pressures decreased by 11–19% in the three groups. Dilution of plasma constituents was also seen in the postoperative fall of platelet counts and of albumin, antithrombin and Factor X levels, most marked in Group III. Albumin levels on day 8 were still only 77–83% of preoperative values. IgG and IgM were decreased and the IgG level was still only 75% of preoperative on day 8. Dilution of other plasma proteins, e.g. von Willebrand Factor, C‐Reactive Protein and Factor VIII:C, were offset by their function as acute phase reactants, with an 8‐to‐10‐fold increase of CRP on day 3 and a two‐fold increase of F VIII:C on day 8. An activation of the coagulation and fibrinolytic systems not only immediately postoperatively, but also extending up to the eighth postoperative day, was shown by elevations of fibrinopeptide A and D‐dimer levels in all groups. We conclude that 3% dextran‐60 in doses not exceeding 1.5 g · kg‐1 can be safely used for plasma volume replacement in surgery, provided there are no preoperative haemostatic disorders. Our findings also indicate that thromboprophylaxis should be continued until at least the eighth postoperative day.
Thiopental binding to human serum albumin in the presence of halothane
Authors: Bücn H. P. , Altmayer P. , Büch U.
Published: January 2009

In vitrothiopental binding (substrate concentration 0.04 · 10‐3M=10 μg/ml) to 1% human serum albumin (HSA)increasedsignificantly from 40.2% (=control) to 47.3% in the presence of 1.18 · 10‐3M = 2.84 vol% halothane. A 4‐fold higher halothane concentration (4.71 · 10‐3M) had an even greater effect with anincreasein the thiopental fraction bound to 55.5%. With a constant HSA concentration (1% or 5%) and thiopental concentrations in the range 0.01–1.5 · 10‐3M or 0.01–0.38 · 10‐3M, respectively, the halothane effect (increasein thiopental binding) was always evident, as well as in other experiments with constant thiopental concentration (0.04 · 10‐3M) and variation in the HSA concentration (0.5 – 10%). Two classes of binding sites for thiopental were apparent at the HSA molecule. In the control experiments the following binding parameters were found: n1=0.01, k1= 181 · 103M‐1; n2=45.73, k2=0.08 · 103M‐1, K=5.47 · 103M‐1. In the presence of halothane the binding parameters changed as follows: n1= 0.14, k1=29.4 · 103M‐1; n2= 11.68, k2=0.42 · 103M‐1, K=9.02 · 103M‐1
The influence of midazolam on the plasma concentrations of bupivacaine and lidocaine after caudal injection of a mixture of the local anesthetics in children
Authors: Giaufre E. , Bruguerolle B. , Morrison‐Lacombe G. , Rousset‐Rouviere B.
Published: January 2009

Twenty children undergoing surgery received a caudal block using 1 ml per kg of a mixture of 50% lidocaine (1%) and 50% bupivacaine (0.25%). They were randomly allocated to two groups, one of which received midazolam 0.4 mg/kg rectally as premedication. Midazolam administration resulted in a significantly lower AUC value for lidocaine but did not influence the plasma concentrations of bupivacaine.
Metabolites of methohexitone do not contribute to its prolonged action on the central nervous system
Authors: Korttila K. , Ghoneim M. M. , Chiang C.‐K. , Nuotto E. , Fischer L. J.
Published: January 2009

Methohexitone has been reported to have a prolonged action on the central nervous system (CNS) despite its relatively short elimination half‐life. A hydroxy metabolite of methohexitone was identified, purified and isolated from the urine collected from eight surgical patients and five mongrel dogs anaesthetized with methohexitone. Using a rotarod device, the CNS‐activity of the human and canine metabolites was tested in mice and compared to that of methohexitone. In this test, the metabolites showed CNS‐depressant activity, but the ED50 (dose needed to affect 50% of the animals) of the metabolites was ten times higher than the ED50 of the parent drug. Because in patients, no traces of the hydroxy metabolite could be found in blood, and in dogs the plasma concentration of the metabolite was about two‐thirds of that of the parent compound, it is unlikely that the residual CNS‐effects of methohexitone are due to its major metabolite, hydroxymethohexitone.
Effects of alfentanil on the responses to awake fiberoptic nasotracheal intubation
Authors: Randell T. , Valli H. , Lindgren L.
Published: January 2009

Intubation conditions and pressor response were assessed in 30 healthy patients undergoing awake nasotracheal intubation. The patients were premedicated with peroral diazepam. All the patients were sedated with intravenous diazepam 0.1 mg/kg. Alfentanil 20 μg/kg or saline was administered in a double‐blind fashion. Alfentanil caused moderate respiratory depression but significantly improved conditions for fiberoscopy. In the control group, arterial pressures and heart rate increased significantly immediately after tracheal intubation. These responses were attenuated by alfentanil.
Effects of precurarisation on suxamethonium induced postoperative myalgia during the first trimester of pregnancy
Authors: Erkola O.
Published: January 2009

Two hundred and fifty women undergoing termination of pregnancy during the first trimester under general anaesthesia were studied to determine the effects of precurarisation on suxamethonium‐induced postoperative myalgia and on the need for postoperative analgesics after suxamethonium. Either alcuronium (0.03 mg/kg), atracurium (0.04 mg/kg), tubocurarine (0.05 mg/kg), vecuronium (0.01 mg/kg) or saline was administered in a double‐blind manner 4 min before giving suxamethonium. An additional 50 patients were studied who received isoflurane rather than precurarisation and suxamethonium. Every pretreatment prevented fasciculations better than did saline (P<0.001). In the saline group, 92% of patients had fasciculations and in the other groups this ranged from 8 to 32%, respectively. On the first postoperative day, 76% of the patients in the saline group had myalgia while myalgia was manifested in 28, 54 and 34% of patients given alcuronium, tubocurarine or vecuronium, respectively (P< 0.05). Atracurium failed in this effect with 62% having myalgia. In the isoflurane group, none of the patients complained of myalgia on the first postoperative morning. The need for analgesics was less (P<0.005) in the isoflurane group (8%) and in the pretreatment groups (18–27%) than in the saline group (42%). It is concluded that precurarisation with tubocurarine, vecuronium or, most effectively, with alcuronium but not with atracurium decreases suxamethonium‐induced postoperative myalgia and seems to be necessary also during the first trimester of pregnancy.
Sublingual buprenorphine as postoperative analgesic: a double‐blind comparison with pethidine
Authors: Moa G. , Zetterström H.
Published: January 2009

Buprenorphine and pethidine as postoperative analgesics were compared in 96 women having gynaecological operations by lower laparotomy. A fixed dose of the respective drug was given in a double‐blind and double‐dummy manner, initially intramuscularly and thereafter by sublingual buprenorphine (0.4 mg) or intramuscular pethidine (75 mg) at the request of the patient during the first 24 h postoperatively. Patients receiving buprenorphine had longer dose intervals and thus needed fewer doses. The analgesic effect, as assessed by a visual analog scale, was similar with both drugs. There were no significant differences between the groups regarding respiratory depression and nausea. It appears that sublingual buprenorphine is as effective and safe as intramuscular pethidine in the postoperative period.
Dose‐response to pancuronium in identical twins
Authors: Goudsouzian N.
Published: January 2009

The dose‐response to pancuronium was determined in identical twins within an hour with the same anesthetic technique. The dose‐response curves did not differ from parallelism, but one infant was more sensitive to pancuronium than the other. The recovery rates were also different. The variation in the dose response to pancuronium seems to extend to identical twins.
Uteroplacental blood flow measured by placental scintigraphy during epidural anaesthesia for caesarean section
Authors: Skjöldebrand A , Eklund J , Johansson H , Lunell N‐O , Nylund L , Sarby B. , Thornström S.
Published: January 2009

The uteroplacental blood flow was measured before and during epidural anaesthesia for caesarean section in 11 women. The blood flow was measured with dynamic placental scintigraphy. After an i.v. injection of indium‐113m chloride, the gamma radiation over the placenta was recorded with a computer‐linked scintillation camera. The uteroplacental blood flow could be calculated from the isotope accumulation curve. The anaesthesia was performed with bupivacaine plain 0.5%, 18–22 ml and a preload of a balanced electrolyte solution 10 ml/kg b.w. was given. The placental blood flow decreased in eight patients and increased in three with a median change of – 21%, not being statistically significant. No correlation between maternal blood pressure and placental blood flow was found.
Visceral pain during caesarean section under spinal and epidural anaesthesia with bupivacaine
Authors: Alahuhta S. , Kangas‐Saarela T. , Hollmén A. I. , Edström H. H.
Published: January 2009

In a randomized study, the incidence of visceral pain was evaluated in 46 patients undergoing elective caesarean section under spinal or epidural anaesthesia with 0.5% bupivacaine. If the patient experienced pain during the operation, a standard visual analogue scale ranging from 0 to 10 was used to assess the degree of pain Visceral pain occurred in 12/23 patients in the spinal group and in 13/23 patients in the epidural group. In neither group was a correlation found between the cephalad level of analgesia or the intensity of cutaneous analgesia in the sacral region, and the presence of visceral pain.
Observations on intracranial dynamics during respiratory physiotherapy in unconscious neurosurgical patients
Authors: Ersson U. , Carlson H. , Mellström A. , Pontén U. , Hedstrand U. , Jakobsson S.
Published: January 2009

The effects of airway care procedures on intracranial dynamics were studied in 12 patients with intracranial lesions. The patients had controlled ventilation and were treated according to a standardized protocol with endotracheal suction and bag squeezing. Intracranial, arterial blood and airway pressures were recorded and cerebral perfusion pressure was calculated. Both methods used for airway care elicited marked changes in intracranial, arterial blood and cerebral perfusion pressures during the treatment session. However, within 1 min after termination of the procedure the different pressure levels returned to pretreatment values except for the intracranial and arterial blood pressure in endotracheal suction. Cerebral perfusion pressure, calculated at different time intervals: 1, 5 and 15 min after the treatment, showed only minor deviations from values before treatment. The mean values varied from 70 to 90 mmHg (9.3 to 12.0 kPa) and the lower limit of the 99% confidence interval of the means was never below 55 mmHg (7.3 kPa). At times complementary administration of sedatives during endotracheal suction was found to induce a drop in arterial blood pressure and cerebral perfusion pressure. In conclusion, patients with severe brain injuries treated on mechanical ventilation are exposed to equal risks when using bag squeezing for airway care as when using traditional endotracheal suction. Regardless of the method used, patients should be adequately sedated before starting the procedure in order to reduce the risk of adverse effects.
Plasma level changes of fentanyl and midazolam after release of a prolonged thigh tourniquet
Authors: Schmitt H. , Batz G. , Knoll R. , Danner U. , Brandl M.
Published: January 2009

In 14 elderly orthopedic patients undergoing total knee joint replacement, the influence of complete arterial occlusion of the limb on the course of plasma levels of fentanyl and midazolam was examined. The patients were premedicated with midazolam intramuscularly (0.05 mg/kg) and were then given neurolept anesthesia in dosages of 0.1 mg/kg midazolam and 0.01 mg/kg fentanyl intravenously prior to the placement of the tourniquet. Up to 4 h after the tourniquet was released, plasma levels of fentanyl and midazolam as well as pH value, Paco2 and plasma lactate levels were measured. In 12 patients there was an increase in fentanyl and in 10 patients an increase in midazolam plasma levels after tourniquet release. The maximum increase varied between 1 min and 2 h after release. The plasma levels of midazolam after removal of the tourniquet varied greatly between individuals. Especially patients older than 70 years showed excessively high concentrations of midazolam. These results would indicate that there can be a clinically significant increase of fentanyl and midazolam levels due to initial reperfusion of the lower extremity following prolonged ischemia. Therefore a correspondingly extended period of postoperative surveillance is advisable.
Disturbances of blood‐flow velocity in the dorsal veins of the hand after vein cannulation and cannula fixation in the anaesthetised patient
Authors: Nitescu P. , Larsson N. , Eriksson E. , Frid I. , Volkmann R. , Haljamäe H. , Linder L. E. , Curelaru I.
Published: January 2009

Modifications of the mean blood‐flow velocity in the dorsal veins of the hand were assessed semi‐quantitatively with continuous wave (CW) Doppler equipment in 32 anaesthetised patients (17 men and 15 women), 23–78 (median= 56) years of age, before and after venous catheterisation with cannula fixation to the skin. Cannulation of the vein caused a 48% reduction in the mean blood‐flow velocity and made it impossible to detect any flow with the equipment used in 22% of the patients. A 10% further reduction in the mean blood‐flow velocity and in the number of subjects with undetectable blood flow was observed after fixation of the cannulae. Age, small vein diameter, and hyperventilation (end‐tidal carbon dioxide 7l & ht3.5 volume %) appeared to be significant factors reducing blood‐flow velocities in the cannulated veins. It is concluded that venous catheterisation and fixation of the cannula induce a significant reduction in the blood‐flow velocity.
Neuromuscular effects of isoflurane in patients with myasthenia gravis
Authors: Nilsson E. , Muller K.
Published: January 2009

Seventeen myasthenia gravis and seven control patients were studied mechano (MMG)‐ and electromyographically (EMG) during isoflurane/oxygen/air anaesthesia. In myasthenic patients the mean train‐of‐four ratio and neuromuscular block (by MMG) during 1.9 MAC isoflurane anaesthesia were 55 ± 9% and 46 ± 12%, respectively. The correlation between simultaneous MMG and EMG measurements was excellent (r2=0.933, P<0.001). The occurrence of HLA‐B8 together with acetylcholine receptor antibodies seems to predispose myasthenic patients to a neuromuscular depression produced by isoflurane. Our current and prior results show that isoflurane possesses approximately twice as strong a neuromuscular blocking effect as halothane in myasthenic patients.
Correlation between EEG and heart rate variation in deep enflurane anaesthesia
Authors: Yli‐Hankala A. , Heikkilä H. , Värri A. , Jäntti V.
Published: January 2009

Variations in heart rate during deep enflurane anaesthesia were studied in 11 women admitted for elective surgery. Correlation was found between heart rate variations and bursts and suppressions in the EEG patterns. The onset of bursts coincided with accelerating heart rate, and the onset of suppressions was combined with a fall in heart rate in all patients. The correlation is not explained by ventilation arrhythmia. Both the cortical electrical activity and heart rate fluctuation are probably controlled by the same subcortical factor.
A prospective study of risk factors and cardiopulmonary complications associated with anaesthesia and surgery: risk indicators of cardiopulmonary morbidity
Authors: Pedersen T. , Eliasen K. , Henriksen E.
Published: January 2009

The aims of this study were: 1) to describe the frequency and type of cardiopulmonary complications, 2) to identify factors significantly associated with cardiovascular and pulmonary complications associated with anaesthesia and surgery, and 3) to estimate the total risk of cardiopulmonary complications for an anaesthetic when a combination of risk factors is present. Seven thousand three hundred and six anaesthetized patients undergoing gastrointestinal, urological, gynaecological, and orthopaedic surgery were included in the study; 6.3% (1:16) had one or more cardiovascular complications requiring intervention associated with anaesthesia and surgery, and 4.8% (1:21) had pulmonary complications. The total incidence of patients with one or more complications associated with anaesthesia and surgery was 9.4% (1:11). Based on logistic regression analyses, our data indicate that the following patient categories constitute high risk patients with regard to cardiovascular complications: patients aged ≥ 70 years, patients with a history of ischaemic heart disease (IHD) with previous myocardial infarction < 1 year, a history of chronic heart failure (CHF), and in patients admitted to major surgery. The extent of pulmonary complications following anaesthesia and surgery was significantly correlated to patients aged ≥ 70 years, preoperative chronic obstructive lung disease (COLD), major surgery, and to general anaesthesia involving muscle relaxants. Attempts to estimate the cardiopulmonary complications which may accompany anaesthesia and surgery provided important information about the anaesthetic course and outcome. With our model it seems possible to distinguish between very different levels of cardiopulmonary risk in the anaesthetic patient.
Treatment of pancreatic pain with interpleural bupivacaine: an open trial
Authors: Ahlburg P. , Noreng M. , Mølgaard J. , Egebo K.
Published: January 2009

This study comprised 12 patients admitted for interpleural catheter treatment of chronic pancreatic pain. After the insertion of a left‐sided interpleural catheter, 20 ml of bupivacaine 0.5% plain was given, followed by top‐ups of 10–20 ml bupivacaine 0.5% as needed. Catheters were left in situ for 12–30 h. Immediate pain relief was achieved in all patients. Five patients had only a single blockade offering pain relief for a median of 33 days. One patient suffering from pancreatic carcinoma remained pain‐free until death 45 days later. Seven patients returned for a second blockade after a median of 10 days. After this second blockade long‐lasting pain relief was achieved in three patients for 70, 105 and 145 days. Two patients experienced pain relief lasting 11–14 days, while in two patients only a short‐lived effect was observed, 3–8 days. Unimportant pneumothorax occurred in one patient. No cardiovascular or respiratory side‐effects were recorded. We consider interpleural blockade an alternative worth further investigations in the future in the treatment of patients suffering from chronic pancreatic pain.
Bradycardia as a side‐effect to oxybuprocaine
Authors: Christensen C.
Published: January 2009

Sinus bradycardia was observed as a side‐effect to the use of 0.4% oxybuprocaine eye‐drops in a 48‐yearold man with acute conjunctivitis. Blood pressure was not measurable during the episode.
Medetomidine premedication in dental surgery ‐ a double‐blind cross‐over study with a new α2‐adrenoceptor agonist
Authors: Kallio A. , Salonen M. , Forssell H. , Scheinin H. , Scheinin M. , Tuominen J.
Published: January 2009

A single 50‐μg dose of medetomidine, a highly selective α2‐adrenoceptor agonist, was administered intravenously as premedication 30 min before surgical third molar extraction under local anaesthesia to ten healthy male subjects in a double‐blind, placebo‐controlled, cross‐over study. Blood pressure, heart rate, plasma catecholamines and Cortisol were measured as indicators of operation‐related stress. Apprehension and pain were assessed with repeated Visual Analogue Scales. The dental surgeon rated the overall effectiveness of the premedications, and the patients reported their subjective preference. Drug‐induced sedation was determined with the Critical Flicker Frequency (CFF) test. The dental surgeon rated medetomidine as significantly more effective premedication than saline placebo. Apprehension was significantly reduced by medetomidine. The patients clearly preferred medetomidine premedication. Blood pressure was lower in the medetomidine session, whereas no significant differences were seen in heart rate. Plasma noradrenaline was lower after medetomidine, but adrenaline and Cortisol levels were not affected. In conclusion, medetomidine may offer a useful alternative to traditional premedications in out‐patient surgery, and its clinical usefulness should also be studied in other anaesthetic paradigms.
A prospective study of mortality associated with anaesthesia and surgery: risk indicators of mortality in hospital
Authors: Pedersen T. , Eliasen K. , Henriksen E.
Published: January 2009

The aims of this study were to: 1) determine the incidences and causes of mortality associated with anaesthesia and surgery, 2) identify important factors associated with mortality in hospital, and 3) estimate the mortality risk associated with anaesthesia and surgery when a combination of risk factors are present. A total of 7306 anaesthetized patients undergoing abdominal, urological, gynaecological, or orthopaedic surgery were included in the study. Of these, 0.05% (1: 1800) died during anaesthesia, 0.1% (1: 730) during the recovery period, and the overall mortality rate in hospital was 1.2% (1: 81). Most deaths occurred in the elderly (70 years of age) and were unavoidable due to progression of the presenting condition, such as advanced cancer, or co‐existing diseases such as cardiopulmonary or renal failure. Of the patients who developed myocardial infarction (MI) following anaesthesia, 67% (8/12) died in the postoperative period. Half of the MI patients who died received regional anaesthesia, and in addition suffered from periods of cardiovascular dysfunction intraoperatively. By utilizing logistic regression analysis, a model for prediction of mortality risk was developed. The model included five significant preoperative predictive variables; age; patients with history of chronic heart disease, and renal disease; emergency surgery; and the type of operation. With this model it is possible to distinguish between patients with very different mortality risks.
Cardiopulmonary complications in high‐risk surgical patients: the value of preoperative radionuclide cardiography
Authors: Pedersen T. , KelbÆk H. , Munck O.
Published: January 2009

In a prospective study we examined the strength of association between preoperative left ventricular performance measured by radionuclide cardiography in patients with cardiac or pulmonary insufficiency (high‐risk patients) and cardiopulmonary complications associated with anaesthesia and surgery. Detailed pre‐, intra‐and postoperative data collected for 7306 anaesthetized patients were included in the study. One hundred and thirty‐one patients (1.8%) were classified as high‐risk patients, and 95 patients were examined with radionuclide cardiography. The results demonstrated a 58% incidence of cardiovascular complications for high‐risk patients when the left ventricular ejection fraction (LVEF) was abnormal (<50% or 70%) compared with 12% when LVEF was normal (50–70%). In addition, high‐risk patients with left ventricular end‐diastolic volume (LVEDV) > 140 ml developed cardiovascular complications in 37% of the cases. Patients admitted to major surgery with LVEF < 50 or > 70% were at greater risk than patients with LVEF = 50–70% as demonstrated by a significant increase in the total incidence of cardiopulmonary complications, 70% vs. 17%. It is appropriate to measure LVEF in patients admitted for major surgery who have an increased risk of cardiopulmonary complications as clinically evidenced by heart failure or severe ischaemic heart disease. As the predictive information given by LVEDV was less than that given by LVEF, there are no clinical reasons for measurement of LVEDV.
Clinical evaluation of an ensemble‐averaging impedance cardiograph for monitoring stroke volume during spontaneous breathing
Authors: Ekman L.‐G. , Milsom I. , Arvidsson S. , Biber B. , Martinell S. , SjÖqvist B.‐A.
Published: January 2009

Simultaneous determination of stroke volume (SV) with an ensemble‐averaging impedance cardiograph (AICG) and the thermodilution technique (TD) was compared in 10 patients scheduled for major vascular surgery. A small, successive increase in SV was achieved by a step‐wise infusion of dextran‐70 and elevation of the patient's legs. The patients were allowed to breathe normally during the measurement procedures. There was no difference between the ability of AICG and TD to monitor changes in SV and the correlation coefficient for the measurement of changes in SV by the two methods was 0.88. There was no difference between the reproducibility of AICG‐ (4.6 ml) and TD‐ (9.2 ml) determined SV or between the coefficient of variation for AICG (4.8%) and TD (9.9%). The mean difference between AICG‐ and TD‐determined SV at the different measurement points (range 1.3–4.2 ml) was well within acceptable limits. In conclusion, the ensemble‐averaging impedance cardiograph described in this study was found to be reliable for monitoring changes in SV during uninterrupted, spontaneous breathing.
Influence of perioperative nalbuphine and fentanyl on postoperative respiration and analgesia
Authors: Rawal N. , Wennhager M.
Published: January 2009

In a double‐blind study the relative postoperative respiratory and analgesic effects of perioperatively administered nalbuphine and fentanyl were compared in 60 females undergoing gynecological surgery under i.v. anesthesia. One milliliter (10 mg) nalbuphine was considered equipotent to 1 ml (100 μg) fentanyl. In the recovery period pain was assessed by visual analog score (VAS) and recovery by Pegboard scoring. Respiratory function was evaluated by continuous monitoring of respiratory frequency and end‐tidal CO2 (ETco2) and by frequent arterial blood gas analyses. The total volume of analgesic required for surgical analgesia was similar in the two groups. Patients in the nalbuphine group showed mild to moderate increases in pulse rate during the intubation phase and in blood pressure during surgery. Fentanyl was more effective in suppressing these cardiovascular responses. Within the first 15 min following recovery, increasing Paco2 and ETco2 as well as respiratory rates below 10/min were noted in 8 patients, who all belonged to the fentanyl group; in 4 of these patients i.v. naloxone had to be administered to reverse respiratory depression. Prolonged sedation was a common feature in patients receiving nalbuphine. It was concluded that fentanyl was superior to nalbuphine in attenuating the pressor responses to intubation and surgery. However, fentanyl was associated with respiratory depression in a considerable number of patients. The quality and duration of postoperative analgesia were similar in the two groups.
The experience of the person ventilating the lungs does influence postoperative nausea and vomiting
Authors: Hovorka J. , Korttila K. , Erkola O.
Published: January 2009

One hundred and ninety‐eight patients undergoing elective abdominal hysterectomy were anaesthetized with isoflurane in nitrous oxide and oxygen. Ventilation before endotracheal intubation was carried out either by an experienced senior or by an inexperienced junior member of the anaesthetic team. The incidence and severity of emesis (none, nausea, retching or vomiting) were assessed five times during the first 24 h after operation. Patients whose lungs had been ventilated by experienced members of staff had significantly less (P<0.05 to 0.01) postoperative emesis in the recovery room (incidence of emesis 35%) and 2–6 h after operation (incidence 27%) when compared to patients whose lungs had been ventilated by inexperienced members of staff (incidence of emesis 54% and 40% in the recovery room and after 2 to 6 h, respectively). The results suggest that the experience of the person ventilating the lungs is associated with postoperative nausea and vomiting.
Comparison of induction with and first hour of recovery from brief propofol and methohexital anesthesia
Authors: BOYSEN K. , SANCHEZ R. , RAVN J. , PEDERSEN E. , KRINTEL J. J. , DYRBERG V.
Published: January 2009

Anesthesia and recovery during the first hour after propofol and methohexital anesthesia for termination of pregnancy, lasting about 12 min, were compared, the latter in a double‐blind manner by means of psychomotor tests (coin counting and continuous auditory reaction time). Muscle movements and hiccups were seen significantly more frequently during methohexital inductions. No differences were seen regarding pain at the site of injection or apnea between the groups. At 15 min after the last dose of anesthetic, recovery after methohexital was ahead of that after propofol, but after 1 h, psychomotor performance was better in the propofol group. Side‐effects during recovery were few, and incidences did not differ significantly. Although the difference in reaction time test was significant, it was hardly large enough to be of any clinical importance. Both drugs are useful for brief outpatient anesthesia, but smoother induction gives propofol an edge over methohexital.
Effects of intravenous administration of local anesthetics on the renal sympathetic nerve activity during nitrous oxide and nitrous oxide‐halothane anesthesia in the cat
Authors: NISHIKAWA K. , FUKUDA T. , YUKIOKA H. , FUJIMORI M.
Published: January 2009

The effects of subseizure doses of lidocaine and bupivacaine administered intravenously (i.v.) on mean arterial pressure (MAP), heart rate (HR) and renal sympathetic nerve activity (RSNA) were studied in cats anesthetized with nitrous oxide (N2O)‐O2 and N2O‐O2‐halothane (1 %). In cats anesthetized with N2O‐O2, MAP decreased briefly (P<0.01) and then returned to the initial level within a minute after the i.v. injection of lidocaine (5 mg/kg, 10 mg/kg). RSNA increased at first and then decreased slightly. In cats with denervated baroreceptors, the change in RSNA after lidocaine 5 mg/kg i.v. was similar to that in cats with intact baroreceptors. In contrast, MAP, HR and RSNA decreased significantly (P<0.01) after i.v. injection of lidocaine during N2O‐O2‐halothane anesthesia. The effects of bupivacaine on RSNA were similar to those of lidocaine. It is concluded that cardiovascular depression following intravenous local anesthetics during N2O‐O2‐halothane anesthesia may be caused by both a decreased sympathetic activity and a direct depressant effect on the myocardium.
Cell‐mediated and humoral immune responses to total hip replacement under spinal or general anaesthesia
Authors: SALO M. , NISSILÄ M.
Published: January 2009

Regional anaesthesia has many advantages over general anaesthesia in hip surgery. When the effects of total hip replacement under spinal or general anaesthesia were compared in 22 patients, the only difference between the groups occurred in PHA‐induced lymphocyte proliferative responses. In contrast, no differences between the groups were observed in leucocyte or differential counts, lymphocyte or subtype counts, most mitogen‐induced lymphocyte proliferative responses, NK‐cell activity, IgG, IgM or IgA production by unstimnlated or PWM‐stimulated lymphocytes, proliferative responses of control lymphocytes with 15% patient serum, or chemiluminescence values in phagocytosis of zymosan opsonized with patient serum. Thus, regional anaesthesia is indicated in total hip replacement for reasons other than the immune response.
The interaction of neuromuscular relaxants with rabbit lung muscarinic receptors
Authors: Sugai Y. , Sugai K. , Mishima M. , Okuda C. , Miyazaki M.
Published: January 2009

The interaction of muscle relaxants with airway muscarinic receptors of rabbit lung was investigated in vitro by the [3H]QNB binding technique. Pancuronium, vecuronium, alcuronium and succinyl choline chloride (SCC) inhibited the binding of [3H]QNB to rabbit lung muscarinic receptors in a dose‐dependent manner. The values of IC50 (the concentration giving 50% inhibition) of pancuronium, vecuronium, alcuronium and SCC were 1.54 times 10‐5, 2.52 times 10‐5, 8.40 times 10‐5, and 4.00 times 10‐3 moll respectively. As the values of Kd increased with minimal change in the value of Bmax, while not influencing the number of receptors, these muscle relaxants had an inhibitory action on the affinity of muscarinic receptors to [3H]QNB in the order: pancuronium ≥ vecuronium > alcuronium > SCC. Applying IC50 values to human conditions, clinical doses of these muscarinic relaxants are unlikely to exhibit any significant vagolytic action in lung tissue.