bluuebunny/crossref_metadata_2025 huggingface dataset:
Recovery from total intravenous anaesthesia. Propofol versus midazolam‐flumazenil
Authors: Steib A. , Freys G. , Jochum D. , Ravanello J. , Schaal J. C. , Otteni J. C.
Published: January 2009

The aim of this study was to compare recovery assessed with the Newman, deletion af a's and postbox tests after total intravenous anaesthesia for procedures lasting more than 90 min, with either propofol (PPF) or midazolam (MDZ), reversed or not by flumazenil (FMZ). Thirty patients scheduled for peripheral surgery were randomly allocated to 3 groups of 10, receiving by continuous infusion until the end of surgery either PPF (n=10) or MDZ (n = 20) combined with alfentanil. FMZ was administered thereafter to 10 patients receiving MDZ until they opened their eyes on command or to a maximum dose of 1 mg. Recovery tests were performed 45, 90 and 180 min after the end of anaesthesia. Results were analysed with non‐parametric tests. Recovery scores were significantly better in the PPF group at all times, reaching control values at 180 min for the three tests. FMZ reversal did not improve the scores compared to those resulting from MDZ alone. This study provides further data in favour of PPF as far as rapid and complete recovery is concerned. The efficiency of FMZ is incomplete and only transient when administered in a single dose.
Importance of fasting in the lymphocyte calcium test for malignant hyperthermia
Authors: Fletcher J. E. , Conner G. E. , Allen G. C. , Huggins F. J. , Rosenberg H.
Published: January 2009

Anaesthetic‐induced increases in cytoplasmic free Ca2+ have been reported to be greater in lymphocytes from malignant hyperthermia (MH) susceptible patients than in those from controls, suggesting that this may be the basis for a less invasive test for MH susceptibility. In the present study the cytoplasmic Ca2+ concentrations of lymphocytes were monitored with indo‐1 in 14 control subjects (nine fasted and five nonfasted) and five fasted MH susceptible and three fasted nonsusceptible patients, diagnosed by the halothane and caffeine contracture tests. No relationship was observed between MH susceptibility and Ca2+ concentrations in lymphocytes in the absence or presence of halothane. There was, however, a relationship in control subjects between fasting and the response of lymphocytes to halothane, with the halothane‐induced Ca2+ increase being considerably larger in nonfasted subjects.
Respiratory and sleep patterns during nocturnal infusions of branched chain amino acids
Authors: Kirvelä O. , Thorpy M. , Takala J. , Askanazi J. , Singer P. , Kvetan V.
Published: January 2009

In the awake, normal subject, infusions of branched chain amino acids (BCAA) alter the ventilatory response to CO2. If this effect extends to the sleep state, it could contribute to our understanding of the neurophysiology of the sleep state as well as having clinical utility in ameliorating or preventing apnea syndromes. This study examined the effect of nocturnal BCAA infusions on sleep patterns (as measured by EEG, chest wall motion, Sao, and end‐tidal CO2) in five normal male subjects. Subjects were monitored with a polysomnograph from 21.00 to 7.00. Each subject was studied double‐blind in random order on three occasions: a) baseline, no infusion (B); b) control, with normal saline infusion (S); and c) treatment, infusion of BCAA (BCAA). Sleep pattern analysis did not demonstrate any measurable effect of the BCAA infusion. End‐tidal CO2levels during BCAA infusion were lower than during baseline or control nights (meank ± s.d.; BCAA: 5.8 ± 0.7 kPa vs B: 6.9 ± 0.1 kPa,P< 0.01 and S: 6.7 ± 0.4 kPa,P< 0.05). This study demonstrates that nocturnal BCAA infusions have effects on respiratory control during sleep; further clinical studies are required to determine whether these data have implications for disease states.
Effect of epidurally administered bupivacaine on atracurium‐induced neuromuscular blockade
Authors: Toft P. , Nielsen H. Kirkegaard , Severinsen I. , Helbo‐Hansen H. S.
Published: January 2009

The effect of epidurally administered bupivacaine on duration, intensity and reversal characteristics of atracurium‐induced neuromuscular blockade was studied in 30 healthy patients anaesthetized with thiopentone, fentanyl, midazolam and nitrous oxide. Fifteen patients received, in addition, epidural anaesthesia with bupivacaine. The remaining patients served as controls. The ulnar nerve was stimulated at the wrist and the evoked twitch response from the adductor pollicis was measured with a force displacement transducer. Neuromuscular blockade was induced with atracurium 0.5 mg i.v. and maintained with repeated doses of atracurium 0.15 mg/kg whenever the twitch height had recovered to 15% of the initial twitch height. After operation, the neuromuscular blockade was reversed with neostigmine when the twitch height had recovered to 15%. In the epidural group the clinical duration of neuromuscular blockade, time until first response to train‐of‐four (TOF) and reversal time were all significantly prolonged (P<0.05). Post‐tetanic count (PTC) after 20 min was also significantly lower in the epidural group (P<0.05). It is therefore concluded that epidurally administered bupivacaine prolongs atracurium‐induced neuromuscular blockade. The clinical implication of the modest prolongation is, however, limited.
Clonidine premedication: a useful adjunct in producing deliberate hypotension
Authors: Toivonen J. , Kaukinen S.
Published: January 2009

The effect of clonidine on the dose requirements of labetalol and isoflurane for hypotension was studied in 20 adult patients undergoing middleear surgery. Group I (10 patients) received as premedication only pethidine 1 mg.kg‐1 im., and Group II (10 patients) clonidine 4–5 pg.kg‐1 p.o. in addition to pethidine. Fentanyl was used for analgesia and d‐tubocurarine for muscle relaxation. The dose of labetalol required to induce hypotension to the mean arterial pressure (MAP) 50 mmHg (6.7 kPa) was 0.85 ± 0.08 mg.kg‐1 in Group I, and 0.56 ± 0.08 mg. kg‐1 in Group II (P<.05). The mean isoflurane concentration in inspiratory gas for the maintenance of hypotension was 0.8 ± 0.1 vol% in Group I, and 0.6 ± 0.1 vol% in Group II (P<.05). Before hypotension, MAP decreased significantly in Group 11, and the heart rate (HR) decreased in both groups. There were no significant differences in MAP and HR between the groups during any phase. Urine flow rates (UF) were lower in Group II (0.23 ± 0.04 ml. min‐1) than in Group I (0.68 ± 0.16 ml. min‐1) before hypotension (P<0.05) and during hypotension (0.08 ± 0.02 ml.min‐1 vs. 0.68 ± 0.32 ml. min‐1, P<0.05). After anaesthesia, there was no difference in UF between the groups. The results indicate that clonidine can be used for deliberate hypotension to decrease the dose requirements of labetalol and isoflurane.
Rectal flunitrazepam as premedication in preschool children. A double‐blind randomized study
Authors: Estiève C. , Murat I. , Saint‐Maurice C.
Published: January 2009

The efficacy of flunitrazepam (0.04 mg. kg‐1) as a premedicant was evaluated in 40 young children of less than 5 years of age in a double‐blind, placebo‐controlled study. Flunitrazepam was given by the rectal route 15 min prior to an inhalational mask induction with halothane. Sedation score, mask acceptance and induction score were significantly better in premedicated children than in the placebo group. There were no hypoxic episodes, prolonged sedation or other complications in either group. This suggests that flunitrazepam administered rectally in a low dose is an acceptable premedication in young children.
EEG burst‐suppression pattern correlates with the instantaneous heart rate under isoflurane anaesthesia
Authors: Yli‐Hankala A. , Jäntti V.
Published: January 2009

The correlation between electroencephalogram (EEG) and instantaneous heart rate was studied in deep isoflurane anaesthesia when the EEG showed a burst‐suppression pattern in 15 patients aged 19–39 years. At the onset of EEG burst, the heart rate started to accelerate, and at the onset of suppression it started to decelerate. These changes in heart rate are similar to those we have previously described with enflurane, despite several differences in the effects of these two anaesthetics on EEG and on the cardiovascular system. We hypothesise that the heart‐rate changes are due to central inhibition mediated by the vagus nerve during EEG suppression.
The use of a laryngeal mask airway in spontaneously breathing patients
Authors: Sarma V. J.
Published: January 2009

The Laryngeal Mask Airway (LMA) is a new type of oropharyngeal airway that provides an alternative to endotracheal intubation and standard mask anaesthesia in certain cases. Once the patient is adequately anaesthetised, it can be inserted blindly, without recourse to laryngoscopy or muscle relaxants. Anaesthetists of all grades, given minimum instruction, were able to provide a clinically satisfactory airway in 49 out of 50 spontaneously breathing, anaesthetised patients. The advantages over standard mask anaesthesia are: better airway control, minimal leakage of anaesthetic gases, secure airway during transport to the recovery ward, and it frees the anaesthetist's hands, as no mandibular support is needed. Postoperative problems were minimal and 97.6% of our patients said that they would prefer a similar anaesthetic in future. LMA does not guarantee against the risk of aspiration and it is not recommended for use in patients who may have a full stomach.
Midazolam and flumazenil in gastroenterologys
Authors: Pearson R. C. , McCloy R. F. , Morris P. , Bardhan K. D.
Published: January 2009

Flumazenil, a specific benzodiazepine antagonist, has been used to reverse sedation in a double‐blind, controlled study of patients undergoing upper gastrointestinal (GI) endoscopy. Forty patients in each of two centres were given a standard dose of either flumazenil (n = 40) or placebo (n = 40) after gastroscopy under midazolam sedation. Assessments were made of degree of sedation, psychomotor ability and amnesia up to 24 h after endoscopy. In patients treated with flumazenil, sedation was effectively reversed within 5 min in 77.5% of cases compared to 27.5% of patients treated with placebo. The difference was both clinically and statistically significant at 5 and 30 min but not at 60 min after reversal. There was no evidence of resedation 18 to 24 h later. Times to complete Trieger dot‐joining tests were significantly faster in the flumazenil group at 5, 30 and 60 min. Amnesia for the procedure was retained but did not occur for events after administration of flumazenil. The only adverse event was severe pain in the arm of one patient during the injection of flumazenil. Flumazenil rapidly and safely reverses midazolam‐induced sedation while retaining amnesia for gastroscopy.
The role of midazolam and flumazenil in urology
Authors: Birch B. R. P. , Anson K. , Gelister J. , Parker C. , Miller R. A.
Published: January 2009

The effects of midazolam (3–10 mg im.) and their reversal by flumazenil were studied in transurethral endoscopic procedures performed using topical analgesia. In one randomised study, patients (n = 84) received either no medication or flumazenil (0.5 mg i.v.) on completion of endoscopy. Recovery was assessed subjectively. Within 15 min, 83% of those receiving flumazenil were considered ready for discharge compared with only 24% of the control group (P<0.001). In a second randomised, double‐blind, placebo‐controlled trial of 44 patients, post‐operative recovery was assessed using five objective psychomotor tests. Whereas the placebo group took up to 2 h to recover, those receiving flumazenil recovered fully or returned to near control values within 15 min. Sedoanalgesia ‐ a technique combining adequate local anaesthesia with sedation (using midazolam) ‐ has wide application in urology, and the introduction of flumazenil has major implications for the practice of day‐case surgery.
The use of midazolam and flumazenil in cardiovascular diagnostic and therapeutic procedures
Authors: Marty J. , Nitenberg A.
Published: January 2009

Sedation is sometimes required for cardiovascular diagnostic or therapeutic procedures. Midazolarn may be proposed in these situations because of its duration of action and because of its moderate haemodynarnic effects. However, the use of midazolam implies that the standards of safety required for all anaesthetic techniques have been applied. The changes in haemodynamic data induced by the administration of midazolam must be taken into account in interpretation of the catheterisation report. At the end of investigation, flumazenil can be administered safely to reverse residual sedative effects of midazolam but its use does not exempt from normal monitoring during the recovery period.
Midazolam and flumazenil in ophthalmology
Authors: Gobeaux D. , Sardnal F.
Published: January 2009

Midazolam's pharmacodynamic properties are used in ophthalmology in several indications: 1. to relieve anxiety and unwanted reactions during radial keratotomy in ambulatory patients; 2. to provide sedation and amnesia during cataract surgery using local anaesthesia, in combination with low doses of phenoperidine; 3. to induce general anaesthesia, combined with fentanyl and vecuronium, for intraocular surgery in the elderly; and 4. to decrease intraocular pressure. Flumazenil is not in routine use but is usually administered to antagonise the deleterious effects of midazolam on upper airway resistances and the respiration system and may be used to reverse “paradoxical”, i.e. anxiogenic reactions to benzodiazepines in the elderly.
The use of midazolam in diagnostic and short surgical procedures in children
Authors: Saint‐Maurice C. , Landais A. , Delleur M. M. , Esteve C. , MacGee K. , Murat I.
Published: January 2009

A new technique of sedation for children is described, in which midazolam (0.2 mg.kg‐1) was administered topically by the nasal route, followed by ketamine (9.0 mg.kg‐1) administered rectally in 32 patients breathing air spontaneously. Sedation was good in 23, seven required further ketamine (1.0 mg.kg‐1 i.v.), and in two, halothane was introduced. There was no evidence of severe respiratory depression except during oesophagoscopy. Cardiovascular stability was excellent. Of 21 patients over 5 years old, 19 developed complete and two partial anterograde amnesia for the administration of ketamine and surgery. The major complications were nausea and vomiting (live patients) and salivation (eight patients). The mean recovery time was 40 min (s.d. 33 min). It provided a relatively safe, adaptable, non‐invasive method of inducing sedation in children.
Awareness and general anaesthesia
Authors: Desiderio D. P. , Thorne A. C.
Published: January 2009

A state exists after the induction of anaesthesia in which patients may be aware of their surroundings yet unable to communicate. This problem of awareness and recall during general anaesthesia is a recent one in the relatively short history of anaesthesia. Prior to the introduction of muscle relaxants in 1942 by Griffith and Johnson, it was felt that “light anaesthesia” would be signified by violent movements. Today, the concepts of anaesthetic depth, awareness, and recall have become more complicated with the addition of numerous newer, shorter‐acting, intravenous anaesthetic agents with varying effects on the conscious state. Several methods have been described to detect awareness. None has yet been found to be totally reliable and numerous reports of awareness can be found in the literature. Light inhalation and total intravenous anaesthesia have been blamed for the majority of these case reports. However, awareness during total intravenous anaesthesia is avoidable with the proper use of a combination of a hypnotic and an analgesic such as midazolam and alfentanil for general anaesthesia.
Autonomic and hormonal responses after the use of midazolam and flumazenil
Authors: NILSSON A.
Published: January 2009

Midazolam, like other benzodiazepine agonists, reduces the autonomic and hormonal responses to emotional or surgical stress. This can be seen as a reduction in catecholamine levels after benzodiazepine treatment. The endocrine response with a reduction in cortisol values is mediated by a decrease in ACTH. The adrenal glands are immediately responsive to exogenous ACTH administration as well as to spontaneous recovery from the benzodiazepine action. Flumazenil given alone does not affect the response to emotional stress, neither does it cause any cardiovascular changes. Following benzodiazepine treatment, flumazenil given in a titrated fashion reverses the inhibitory effects of the agonists.
Safety of rapid administration of flumazenil in patients with ischaemic heart disease
Authors: Croughwell N. D. , Reves J. G. , Will C. J. , Kasson B. J. , Goodman D. K.
Published: January 2009

The purpose of this study was to determine if higher (36 μg.kg‐1) doses of flumazenil (a new benzodiazepine (BZ) antagonist) produced an effect on haemodynamics. Twelve patients with class III‐IV angina were entered into this double‐blind randomised placebo‐controlled study. BZ were withheld for 2 weeks prior to surgery. Patients were placed on an ambulatory monitor 18 h prior to surgery to record changes in heart rate rhythm and ST segment changes. The patients were given secobarbital 100–200 mg and morphine 0.12 mg.kg‐1 90 min prior to surgery. Flumazenil or placebo was given in divided doses every 3 min (1 mg, 1 mg, 1 mg). Complete haemodynamic profiles were obtained at baseline and 2 min following each injection of flumazenil. Flumazenil produced a minimal but statistically significant reduction in systolic blood pressure (147 13.9 to 137 18.4 mmHg) and diastolic blood pressure (74 14.8 to 67 13 mmHg). There was no consistent effect on heart rate, pulmonary capillary wedge pressure or cardiac index. We conclude that flumazenil is safe when administered in relatively high doses to patients with ischaemic heart disease who have not received benzodiazepines.
Speed of reversal of midazolam‐induced respiratory depression by flumazenil ‐ a study in patients undergoing upper G.I. endoscopy
Authors: Carter A. S. , Bell G. D. , Coady T. , Lee J. , Morden A.
Published: January 2009

Intravenous midazolam was given to 17 patients coming to upper G.I. endoscopy. All patients had an ear oximeter and calibrated induction plethysmograph attached to record oxygen saturation and minute volume continuously. Midazolam induced significant depression of respiration. Following removal of the endoscope, a new base line was obtained before giving intravenous flumazenil in an attempt to reverse the sedative and ventilatory effects of midazolam. When 0.5 mg of flumazenil was given over 20 s, followed by 0.1 mg every minute, up to a total of 1.0 mg, all patients were apparently awake in under 2 min. Although the flumazenil had clearly reversed the sedative effects of midazolam, the ventilatory effects were largely uninfluenced. The implications are discussed.
Anaesthesia techniques for midazolam and flumazenil ‐ an overview
Authors: Lauven P. M. , Kulka P. J.
Published: January 2009

Midazolam, the latest henzodiazepine agonist, may be used in doses of 0.15 to 0.2 mg.kg‐1 for induction of anaesthesia. It provides good correlation between plasma concentration and anaesthetic effect with an interindividual variability of only 20–25%. On this basis, dosage recommendations for midazolam in total intravenous anaesthesia techniques are possible, aiming at hypnotic plasma concentrations of at least 250 ng.ml‐1. Due to its biological half‐life of 150–180 min and interindividual differences in drug susceptibility, prolonged recovery periods have been observed that can safely and reliably be antagonised by flumazenil, if necessary. It is recommended that flumazenil be administered carefully by titration in increments of 0.1 mg.min‐1 to avoid emergence reactions by awakening too fast (tachycardia, hypertension). Usually a mean total dose of 0.4–0.5 mg will lead to prompt awakening.
Midazolam and flumazenil in neuroanaesthesia
Authors: am Esch J. Schulte , Kochs E.
Published: January 2009

Of the numerous benzodiazepines currently available, only a few are used in anaesthetic practice. Midazolam is utilised as a premedicant, sedative, and an induction agent and produces minimal depression of ventilation or of the cardiovascular system. The anticonvulsant activity is similar to that of diazepam. In neuroanaesthesia midazolam may be an acceptable alternative to other intravenous induction agents like barbiturates or etomidate in patients with compromised intracranial compliance. Midazolam produces dose‐related reductions in cerebral blood flow and cerebral oxygen consumption. However, midazolam does not necessarily prevent increases in intracranial pressure during induction of anaesthesia. In the electroencephalogram (EEG) midazolam produces a reduction in alpha‐activity, an increase in theta‐delta‐activity and low‐voltage beta‐activity. Midazolam like other benzodiazepines does not affect early components of auditory and somatosensory evoked responses, whereas late cortical responses may be suppressed. Flumazenil, a specific benzodiazepine antagonist, has been demonstrated to be effective in reversing benzodiazepine‐induced sedation. In the EEG midazolam‐induced changes vanish almost instantaneously. Flumazenil is also effective in restoring the amplitudes of cortical auditory and somatosensory evoked responses. However, as has been demonstrated in head‐injured patients and animal experiments after incomplete cerebral ischaemia, increases in cerebral blood flow and intracranial pressure cannot be excluded after flumazenil administration. When utilising flumazenil for wake‐up procedures in midazolam‐sedated patients with pathological intracranial compliance, flumazenil has to be titrated very carefully in low doses over prolonged periods.
Tolerance to severe hypoxia: lessons from Mt. Everest
Authors: West J. B.
Published: January 2009

Human tolerance to chronic severe hypoxia has been elucidated by two recent high altitude studies: the 1981 American Medical Research Expedition to Everest, and Operation Everest II, a 40‐day low pressure chamber‐simulated ascent of Everest. The severe oxygen deprivation of extreme altitudes can only be tolerated because of an enormous increase in ventilation which defends the alveolar Po2 against the reduced inspired value. Nevertheless the arterial Po2 on the Everest summit is less than 30 mmHg. The hyperventilation results in a very low arterial Pco2 which causes severe respiratory alkalosis. This has the advantage of increasing the oxygen affnity of hemoglobin and accelerating the oxygen loading by the pulmonary capillary under diffusion‐limited conditions. Cardiac function is astonishingly well maintained up to extreme altitudes. The relationship between cardiac output and work rate is the same as at sea level, and there is evidence that myocardial contractility is well preserved in spite of the extreme hypoxemia. However, there is impairment of central nervous system function at high altitude which persists following return to sea level. Significant abnormalities of motor coordination persisted for more than 12 months in most members of the Everest expedition. There is evidence that the climbers who ventilate most at high altitude have the most central nervous system impairment, presumably because of the more severe cerebral vasoconstriction.
Hypoxic pulmonary vasoconstriction in the adult respiratory distress syndrome
Authors: Jolin Ase , Bjertnæs Lars
Published: January 2009

Increased pulmonary vascular resistance (PVR) and microvascular hyperpermeability resulting in lung edema and arterial hypoxemia are mainstays in the development of adult respiratory distress syndrome (ARDS). The proposed pathophysiologic mechanisms include activation of complement and polymorphonuclear leukocytes secreting lysozomal enzymes, toxic oxygen metabolites (TOM) and eicosanoids. Platelets and coagulation factors are also involved, and in the most severe cases even monocytes are activated as reflected in release of thromboplastin. The latter may elicit disseminated intravascular coagulation (DIG). Under physiologic conditions lung blood flow is diverted from poorly to better oxygenated areas by way of hypoxic pulmonary vasoconstriction (HPV) thereby counteracting a decrease in arterial oxygenation. Many vasoactive substances have been proposed and again refuted as possible mediators of HPV. In this study we have focused on the following: histamine, catecholamines, arachidonates, calcium, phosphoinositides and TOM as well as endothelium‐derived relaxing and constricting factors. Whether HPV is present in ARDS and whether it is advantageous or not seems to depend on the stage and extent of disease. We discuss possible interactions between HPV and ARDS mediators and between HPV and various vasoactive agents tested for therapeutic effects. Out of the abundance of mediators released, prostacyclin, prostaglandin E1, activated complement and platelet activating factor have been shown explicitly to inhibit HPV whereas others are suspected of doing so. In therapeutical use, prostacyclin has proved to reduce PVR and at the same time enhance cardiac output and oxygen delivery. In mild to moderate ARDS, improvement of arterial oxygenation has also been obtained employing almitrine bismesylate, a potentiator of HPV. Experimentally, adenosine effectively reduces increments in PVR and microvascular permeability with modest effects on systemic circulation. However, further investigations are warranted to decide whether adenosine or more specific blockers as, for instance, monoclonal antibodies against tumor necrosis factor should be integrated in ARDS therapy in the future.
Measurement of extravascular lung water — methods and clinical implications
Authors: Leksell L. G.
Published: January 2009

The estimation of changes in extravascular lung water during different experimental and clinical conditions forms an intriguing field of research. Present methods for the measurement of lung water are difficult to apply in day‐to‐day clinical practice. Most methods are not only low in accuracy and sensitivity but are also invasive. A new indicator‐dilution technique using heavy water and idiocyanine green as diffusible and nondiffusible indicators, respectively, may provide us with a new investigative method for longterm bedside estimation of lung water.
Radiospirometry V/Q
Authors: Tokics Leif
Published: January 2009

Single photon emission computerized tomography (SPECT) of the lungs was used for topographical determination of V/Q ratios in anaesthetized‐paralyzed subjects. Ventilation and perfusion were estimated from the distribution of an inhaled aerosol containing a radioactive isotope and injected macroaggregates of human albumin tagged with another isotope. There was a prominent gradient of V/Q ratios in the vertical direction. In the horizontal plane there were marked gradients of both ventilation and perfusion of similar appearance with maxima in central lung regions, resulting in only small gradients of V/Q ratios.
Extracorporeal carbon dioxide removal performed with surface‐heparinized equipment in patients with ARDS
Authors: Bindslev L. , Böhm C. , Jolin A. , Jonzon K. Hambraeus , Olsson P. , Ryniak S.
Published: January 2009

To avoid the drawbacks of systemic anticoagulation during prolonged extracorporeal circulation in patients with adult respiratory distress syndrome (ARDS) a heparinization technique has been developed by which partially degraded heparin can be covalently end‐point attached to the surface of the equipment constituting the extracorporeal circuit (Carmeda Bio‐Active Surface, CBAS) thereby localizing the anticoagulatory effect. Since 1986 we have used extracorporeal circuits and membrane lungs coated with the CBAS for extracorporeal lung assistance (ECLA) in 14 patients suffering from ARDS. The patients were on ECLA for 3 to 55 days with a survival rate of 43%. Our experience so far is that by using equipment coated with CBAS it is possible to perform long‐term extracorporeal circulation with a minimum of intravenously administered heparin, thus avoiding the risk of major coagulation defects.
The pathophysiology of shock
Authors: Haljamäe H.
Published: January 2009

Trauma often includes considerable losses of blood and plasma that may lead to hypovolemia and shock. The initial response of the body to trauma and hemorrhage is characterized by a neuroendocrine‐mediated general defence reaction for the maintenance of circulatory homeostasis and substrate availability for vital organ function. Endogenous fluid is mobilized from intracellular and interstitial sources into the vascular compartment. This transcapillary refill is achieved by activation of glucoseosmotic and neurogenic adaptive vascular mechanisms. The metabolic consequences of insufficient tissue perfusion are anaerobic glycolysis with increased production of lactate and hydrogen ions, acidosis, impaired mitochondrial energy production, disturbed ionic homeostatis across cell membranes, and reduced functional capacity of tissue cells. The shock‐and trauma‐induced alterations in tissue perfusion and metabolism vary, depending on the autoregulatory capacity of an organ, its basal metabolic requirements, its high energy phosphagen reserves, and its ongoing functional activity. Metabolic alterations impairing organ function occur early in the kidney and the liver and late in the heart and the brain. The ischemic tolerance of the skeletal muscle cell is considerable but vast amounts of lactic acid are produced, which at reperfusion will reach central blood and disturb vital organ function. Tissue factors released from mechanically traumatized or hypoxic cells will activate cascade systems and may induce alterations in remote organs, i.e. result in the development of multiorgan failure.
Cascade system activation in shock
Authors: Bengtsson A.
Published: January 2009

Trauma and sepsis activate different cascade systems. Activation of the coagulation and clotting systems, of the kinin‐kallekrein system and of the complement system are important etiological mechanisms behind development of the adult respiratory distress syndrome (ARDS) and multisystem organ failure (MOF) after extensive trauma or severe septic situations. Activation of complement with the release of anaphylatoxins and terminal complement complexes is associated with increased mortality and development of ARDS and MOF after major surgery and in situations of septic shock. The anaphylatoxins have potent vascular properties and they activate leukocytes. Their effects on the leukocytes lead to the release of free oxygen radicals, different lysosomal enzymes and cytokines, leukotrienes and histamine. All these inflammatory mediators may, if released in extensive amounts, induce microvascular injury and interstitial edema. If this process takes place in the lung, ARDS may develop and if other organs, i.e the liver and the kidneys, are involved, MOF may be the result.
Manipulation of the immunoinflammatory reaction in clinical sepsis
Authors: Sjölin J.
Published: January 2009

For many years patients with sepsis and septic shock have been treated with antibiotics, fluids, surgery (if indicated) and, in the more severe cases, inotropic and ventilatory support. During recent years there has been an intensive development of new treatments based on increased knowledge of the pathophysiology. This presentation will focus on treatments modulating the immunoinflammatory response, which are either available in clinical practice today or which will be available in the near future. It is concluded that optimal therapy depends on the stage of the septic disease as well as the gram stain of the causative bacteria.
Volume substitution in shock
Authors: Haljamäe H.
Published: January 2009

Shock treatment seems optimal when a “balanced” fluid and volume regimen, including both crystalloid (Ringer's acetate) and about 3% colloid, is used. Dextran is the colloid of choice due to its beneficial effects on plasma volume, hemorrheology, and microvascular blood flow. Dextrans exert, in addition, inhibiting effects on the shock‐ and trauma‐induced activation of the cascade system, whereby the risk of complications in the form of multiple organ failure is reduced. Infusion of red blood cells, plasma or thrombocytes should be based on a proper assessment of each individual patient's actual need of oxygen transporters and coagulation factors.
Attenuating the hypertensive response to laryngoscopy and endotracheal intubation using awake fibreoptic intubation
Authors: Hawkyard S. J. , Morrison A. , Doyle L. A. , Croton R. S. , Wake P. N.
Published: January 2009

Blood pressure and pulse rate measurements were recorded in 35 patients undergoing endotracheal intubation during general anaesthesia (Group A), and 35 patients who had an awake fibreoptic intubation under local anaesthesia (Group B). The mean arterial pressure in Group A rose by a mean of 35 mmHg immediately after intubation, compared with a mean fall of 9 mmHg in Group B. The mean pulse rate in Group A rose by 24 beats per minute (b.p.m.) immediately after intubation, compared with a rise of 3 b.p.m. in Group B. Both these differences were statistically significant (P< 0.0001 and P< 0.001 respectively, Mann Whitney U test). Postoperative discomfort was assessed 24 h later by means of linear analogue scales. There was a statistically higher mean score in relation to nose discomfort in Group B (P< 0.002). Awake fibreoptic intubation successfully reduces the pressor response to endotracheal intubation in normotensive adults. It is suitable for use in those patients who are at risk from the pressor response.
Effectiveness of pressure support ventilation for mechanical ventilatory support in patients with status asthmaticus
Authors: Tokioka H. , Saito S. , Takahashi T. , Kinjo M. , Saeki S. , Kosaka F. , Hirakawa M.
Published: January 2009

We compared the effects of pressure support ventilation (PSV) with those of assist control ventilation (ACV) on breathing patterns and blood gas exchange in six patients with status asthmaticus. Both PSV and ACV delivered adequate minute ventilation (PSV: 7.5 ± 1.4 l/min/m2, ACV: 7.3 ± 1.3 l/min/m2) to correct respiratory acidosis (pH = 7.33 ± 0.12 during both PSV and ACV) and prevent hypoxia. Peak airway pressure during PSV was significantly lower with the same tidal volume than that during ACV (PSV: 30 ± 10 cmH2O (2.9 ± 1.0 kPa), ACV: 50 ± 13 cmH2O (4.9 ± 1.3 kPa)). The lower airway pressure during PSV was due to persistent inspiratory muscle activity. The oxygen cost of breathing estimated by oxygen consumption was equivalent in both modes. We conclude that PSV is effective in supplying tidal volumes adequate to improve hypercarbia at markedly lower airway pressures than ACV.
Postoperative pulmonary complication rate and long‐term changes in respiratory function following esophagectomy with esophagogastrostomy
Authors: Crozier T. A. , Sydow M. , Siewert J. R. , Braun U.
Published: January 2009

Upper abdominal surgery has a high incidence of postoperative respiratory complications. Although operations involving a thoracic as well as an upper abdominal incision as encountered in esophageal surgery are likely to be associated with an even higher complication rate and perhaps permanent alterations of respiratory function, only a few studies have addressed this problem. We evaluated the postoperative course of patients undergoing thoracoabdominal esophagectomy with esophagogastrostomy. Twenty patients were evaluated, of whom 10 (50%) developed respiratory complications as defined by our criteria, which were the simultaneous occurrence of rectal temperature over 38°C on the first postoperative day and radiographic evidence of pulmonary infiltration. Although there is no general consensus regarding the diagnostic criteria of a postoperative pulmonary complication, we were able to validate the clinical relevance of our definition by showing that these patients suffered from a more severe and more prolonged impairment of global oxygen exchange than those who did not fulfill the criteria. They also required a longer period of respiratory support (median duration of intubation 12 vs. 3 days, P<0.005). A comparison of the preoperative pulmonary function with that determined at least 6 months after the operation showed that only vital capacity (VC) and total lung capacity (TLC) were significantly (P<0.05) reduced following the operation, but not to a clinically relevant degree (VC ‐6%, TLC ‐7%).
Cardiovascular effects of acute changes in extracellular ionized calcium concentration induced by citrate and CaCl2infusions in conscious, chronically instrumented dogs and their interactions with ganglionic blockade
Authors: Hysing E. S. , Chelly J. E. , Doursout M.‐F. , Merin R. G.
Published: January 2009

To assess the hemodynamic effects of acute changes in extracellular ionized calcium concentration, [Ca2+], seven dogs were chronically instrumented to measure heart rate, aortic, left atrial, and left ventricular (LV) pressures, cardiac output, and coronary and renal blood flows. [Ca2+] was lowered 0.35 mmol ± l‐1by citrate infusion and then increased 0.35 mmol ± l‐1above control level by CaCl2infusions. This protocol was performed in the conscious dogs with and without ganglionic blockade (chlorisondamine 2 mg ± kg‐1). LV dP/dtmaxdecreased at low [Ca2+] and increased at high [Ca2+] during all conditions. The other hemodynamic variables measured were only slightly changed by changing [Ca2+] without ganglionic blockade and surprisingly even less with ganglionic blockade. Therefore, the lesser hemodynamic effects induced by acute changes in [Ca2+] in the conscious compared with anesthetized dogs cannot be explained by the depressant effects of the anesthetics upon the autonomic nervous system. We have suggested that the binding of Mg2+to citrate may be of importance for the minor hemodynamic effects in the conscious dogs.
Timing of peak pressor response following endotracheal intubation
Authors: Hickey S. , Cameron A. E. , Asbury A. J. , Murray G. D.
Published: January 2009

The study was designed to measure the timing of the peak cardiovascular response following laryngoscopy and endotracheal intubation. Thirty patients ASA 1 or 2 were studied, with arterial pressure being continuously monitored using the Ohmeda 2300 Finapres. Patients were randomised to receive either propofol 2.5 mg ± kg‐1 (Group A) or thiopentone 4.5 mg ± kg‐1 (Group B). The mean time to complete laryngoscopy and intubation was 26 s in Group A and 20 s in Group B. The peak response occurred on average 31 s after the start of the stimulus in Group A and after 32 s in Group B. In 8 out of the 30 cases the peak response occurred during the period of stimulation. Systolic pressure fell on average by 2.6 kPa (20 mmHg) (range 0 to 5.9 (45 mmHg)) from its peak value to the value measured at the 1‐min time mark in the propofol group, and by 2.3 kPa (17 mmHg) (range 0.4 (3 mmHg) to 3.8 (29 mmHg)) in the thiopentone group. We conclude that the use of slow arm‐cuff‐based arterial pressure measurement techniques may miss important hypertensive episodes during laryngoscopy and endotracheal intubation. The effectiveness of agents in obtunding the pressor response may thus be misinterpreted.
Hyperglycemia in global cerebral ischemia and reperfusion: a 31‐phosphorous NMR spectroscopy study in rats
Authors: Haraldseth O. , Nygård Ø. , Grønås T. , Southon T. , Gisvold S. E. , Unsgård G.
Published: January 2009

31‐phosphorous magnetic resonance spectroscopy was used in a rat model of 10 min severe incomplete forebrain ischemia (two‐vessel occlusion with hypotension) to assess the effect of hyperglycemia on intracellular pH and high energy phosphates during ischemia and early reperfusion. One group (n = 8) with preischemic hyperglycemia (serum glucose 20 mmol ± l‐1) showed an increased intracellular acidosis (pH 6.35) during ischemia compared to 6.55 in the normoglycemic control group (n=7, P<0.001), but the recovery of phosphocreatine and ATP in early reperfusion was the same in the two groups. Another group (n = 7) was normoglycemic during ischemia, but received an i.v. bolus of glucose during the first minute of reperfusion. In this group the recovery of intracellular pH in early reperfusion was slower than in the control group (0.034 ± 0.006 pH units per minute compared to 0.052 ± 0.11 in the controls, ± s.d. and P<0.01).
Propofol anaesthesia versus paracervical blockade with alfentanil and midazolam sedation for outpatient abortion
Authors: Ræder J. C.
Published: January 2009

Propofol anaesthesia was compared with paracervical blockade in a prospective, randomized study of 59 abortion patients. All the patients received alfentanil 0.01 mg/kg i.v. at the start of anaesthesia and were randomized into two groups. Group R (regional, 31 patients): midazolam 0.1 mg/kg i.v. and paracervical blockade with 2 times 10 ml of mepivacaine 20 mg/ml + adrenaline 0.005 mg/ml. Group G (general, 28 patients): propofol 2.0 mg/kg i.v. induction and 75% nitrous oxide in oxygen spontaneous respiration. In 10 patients from the R‐group venous blood samples were taken regularly for 30 min for serum concentration measurements (gas chromatography) of mepivacaine. Pain during induction of anaesthesia was remembered by 17% in Group G and 4% in Group R, whereas 8% in Group R remembered pain during the procedure compared with none in Group G. Of the patients in Group G, 25% had apnoea compared with none in Group R. In Group R the patients slept for 2.5 ± 3.8 min (mean ± s.d.) after induction compared with 12 ± 4.0 min in Group G. Except for a better p‐deletion score 30 min after the procedure in Group G, there was no difference in recovery function between the groups. Of the patients in Group G, 67% experienced postoperative pain compared with 23% in Group R. Maximum serum mepivacaine concentration (Group R) was reached at 15–30 min, range 1.5–5 μg/ml.
Pulmonary effects of body position, PEEP, and surfactant depletion in dogs
Authors: Larsson A. , Gilbert J. T. , Bunegin L. , Gelineau J. , Smith R. B.
Published: January 2009

The influence of position (sphinx, lateral, supine), surfactant depletion, and different positive end‐expiratory pressure (PEEP) on functional residual capacity (FRC), series dead space (VdS) and compliance of the respiratory system (Crs) were evaluated in five dogs. Ventilation homogeneity as measured by an index (multiple breath alveolar mixing efficiency), oxygenation, and cardiovascular hemodynamics were additionally examined. The dogs were anesthetized with halothane, paralyzed, and mechanically ventilated. FRC and VdS were found to be notably large in dogs, 45 ± 8 ml/kg and 6 ± 1 ml/kg, respectively. FRC and ventilation homogeneity were improved in the sphinx position (prone position with upright head). Surfactant depletion by lung lavage with 37±C saline caused an immediate and stable decrease in FRC, Crs, and oxygenation (P<0.05, respectively) for about 5 h without marked effects on the circulatory system. FRC and VdS increased with increasing PEEP. At the highest PEEP, 10 cmH2O (1 kPa), Crs decreased (P<0.05) and ventilation became more uneven, indicating alveolar overdistension.
Effects of nitrous oxide on cerebral haemodynamics and metabolism during isoflurane anaesthesia in man
Authors: Algotsson L. , Messeter K. , Rosén I. , Holmin T.
Published: January 2009

Seven normoventilated and five hyperventilated healthy adults undergoing cholecystectomy and anaesthetized with methohexitone, fentanyl and pancuronium were studied with measurement of cerebral blood flow (CBF), cerebral metabolic rate of oxygen (CMRo2), and quantified electroencephalography (EEG) under two sets of conditions: 1) 1.7% end‐tidal concentration of isoflurane in air/oxygen; 2) 0.85% end‐tidal concentration of isoflurane in nitrous oxide (N2O)/oxygen. The object was to study the effects of N2O during isoflurane anaesthesia on cerebral circulation, metabolism and neuroelectric activity. N2O in the anaesthetic gas mixture caused a 43% (P<0.05) increase in CBF during normocarbic conditions but no significant change during hypocapnia. CMRo2 was not significantly altered by N2O. EEG demonstrated an activated pattern with decreased low frequency activity and increased high frequency activity. The results confirm that N2O is a potent cerebral vasodilator in man, although the mechanisms underlying the effects on CBF are still unclear.
Effect of continuous interscalene brachial plexus block on diaphragm motion and on ventilatory function
Authors: Pere P. , Pitkänen M. , Rosenberg P. H. , Björkenheim J.‐M. , Linden H. , Salorinne Y. , Tuominen M.
Published: January 2009

Interscalene block may cause phrenic nerve block and decreased diaphragmatic motion. We evaluated the effect of continuous interscalene block on ventilatory function and diaphragmatic motion. We studied ten patients scheduled for surgery or manipulation of the shoulder. Preoperatively, the patients underwent spirometry and double‐exposure chest radiography. They received an interscalene block with 0.75% bupivacaine. Thereafter, 0.25% bupivacaine was infused into the interscalene space for 24 h. Spirometry was repeated three times and double‐exposure radiography twice. The maximal inspiratory and expiratory pressures were measured repeatedly. Haemoglobin oxygen saturation (SPo2) was monitored with pulse oximetry. The block provided adequate anaesthesia for surgery or manipulation. All patients had a marked ipsilateral paresis of the diaphragm in the radiographs 3 h after the initial block. Twenty‐one hours later five patients had diaphragmatic motility comparable to the situation before the block. In the other five patients, the amplitude of diaphragmatic motility on the side of the block was only 4–37% of the values before the block. All patients had a clear reduction in forced vital capacity (FVC), forced expiratory volume in ls (FEV1) and peak expiratory flow (PEF) 3 and 8 h after the block without signs of dyspnoea. In conclusion, in all our patients interscalene block caused an ipsilateral hemidiaphragm paresis, which in five of ten patients persisted until the end of the continuous block.
Post‐dural puncture headache in young orthopaedic in‐patients: comparison of a 0.33 mm (29‐gauge) Quincke‐type with a 0.7 mm (22‐gauge) Whitacre spinal needle in 200 patients
Authors: Lynch J. , Arhelger S. , Krings‐Ernst I.
Published: January 2009

The incidence of postdural puncture headache (PDPH) following spinal anaesthesia with a 0.33 mm (29‐gauge) and two types of 0.7 mm (22‐gauge) Whitacre needles was investigated in 400 patients less than 40 years old. The incidence of PDPH was 2% in the 0.33 mm group, and 3.5% in the 0.7 mm group. Headache of other origin was seen in 12 patients (6%) in the 0.33 mm and in five patients (2.5%) in the 0.7 mm group. These differences were not significant. The failure rate was significantly higher in the 0.33 mm group (8.5% vs 2%) than in the 0.7 mm group (P<0.05). It is concluded that the 0.33 mm needle is associated with a low incidence of PDPH in young patients, but has a significantly higher failure rate than the Whitacre 0.7 mm needle, which is also a suitable choice in this age‐group because of its ease of handling and the low incidence of PDPH.
Pharmacodynamic properties of propofol during recovery from anaesthesia
Authors: Paut O. , Guidon‐Attali C. , Viviand X. , Lacarelle B. , Bouffier C. , François G.
Published: January 2009

Propofol was used to induce and maintain anaesthesia in 20 healthy adult ASA physical status 1 patients undergoing dental surgery. Recovery was studied using psychometric tests and clinical assessment while propofol blood levels were obtained at the same study times. Recovery was rapid and there were no significant differences 60 min after anaesthesia (t60) for the tracing test and 90 min for the choice reaction time. All patients were orientated in time at t30 and in space at t45; Stewart's score was maximal in all patients at t60; recovery of normal walking was slower, i.e. t120. Return to baseline for psychometric function was linked to a decrease in propofol blood level, for both the tracing test (P<10‐6) and the choice reaction time (P<10‐3). We conclude that propofol is a suitable anaesthetic agent for induction and maintenance of short duration dental anaesthesia.