bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of saccahc eye movements as an objective test of recovery from anaesthesia
Authors: PAUT O. , VERCHER J.‐L. , BLIN O. , LACARELLE B. , MESTRI D. , DURAND A. , GARUTHIER G.M. , CAMBOULIVES J
Published: January 2009

Saccadic eye movements have been previously used to assess residual effect of anaesthetics, but this test is seldom compared to other psychomotor tests. The aim of the present study was to validate saccades as a recovery index in relation to frequently referred subjective and psychometric tests.

Eight healthy subjects were tested before and after intra‐muscular injection of either placebo or 0.15 mg · kg‐1 of midazolam. Each session consisted of a saccadic test (recorded by electro‐oculography), a choice‐rcaction‐time test (CRT), a subjective statc‐of‐alertness test (11 visual analogic scales) and blood sampling (to monitor midazolam plasma concentration), before and 30 (t30;, 60 (t60), 120 (t120), 180 (t180), 240 (t240) minutes after drug administration.

In the placebo group, there was no change in subjective assessment, saccade characteristics (latency, peak velocity and duration) or CRT results. In the midazolam group, 6 subjective items changed with different time‐courses, when compared to baseline: from t30 to t120 (drowsy, in shape, tired, clumsy, strong) and at t120 (woolly). Saccade latency and duration were significantly different from t30 to t120 and until t180 for peak velocity. CRT performance was significantly altered from t30 to t120. Midazolam plasma concentration decreased from 177±33 ng · ml‐1 at t30 to 47±12 ng · ml‐1 at t240. At this latter time, sensorimotor functions returned to the baseline. All subjects fulfilled the clinical conditions for home discharge 4 hours after administration.

These results suggest that a saccadic eye movement test is a sensitive and reliable tool for the assessment of residual effect of anaesthetics. This test was found to be more sensitive than CRT test since peak saccadic velocity was the last psychometric parameter to be returned to baseline after midazolam injection. This study also confirms the poor reliability of subjective assessment, as subjects tended to underestimate the alteration of their performance immediately following drug injection.
Streptococcal myositis and tissue necrosis with intramuscular administration of diclofenac
Authors: RYCNESTAD T. , KVAM A. M.
Published: January 2009

The authors describe a fatal case of a group A β‐haemolytic streptococci infection. The symptoms seemed to have been initiated by minor skin trauma; intramuscular injections of diclofenac (Voltaren®) and metoclopramide (Primperan®) after which the patient developed extensive muscle necrosis. The clinical course was rapid and he died within 48 hours after the first injection from circulatory collapse, probably due to overwhelming septicaemia with group A β‐haemolytic streptococci. Streptococcal myositis is a rare and extremely serious complication of skin trauma. Muscle necrosis is also a known but rare side effect of intramuscular administration of drugs (the “Nicolau syndrome”) in which non‐steroid anti‐inflammatory drugs are often implicated. The case is discussed in the context of this specific syndrome.
The slow penetration of enzymebased biosensors into clinical chemistry analysis
Authors: CHRISTIANSEN T. F. , JAKOBSEN K. M.
Published: January 2009

In 1972 Yellow Springs Instrument Co., Inc. (YSI) introduced the first commercial instrument which could measure glucose in diluted whole blood by use of an enzyme‐based biosensor. Until 1986 YSI had a monopoly of this technology for clinical chemistry. Since 1986 another ten companies have commercialized the technology. Enzyme‐based biosensors for clinical chemistry are now available for glucose, lactate, and urea. Until 1975 the annual number of papers on enzyme‐based biosensors is sparse, but from then there is a significant increase in the number of publications. The commercial interest in glucose is reflected in the number of patents covering this analyte: close to fifty per cent of the patents cover this type of sensor while less than ten per cent of the scientific papers are on glucose sensors. The major problems in developing enzyme‐based biosensors for clinical chemistry have been achievement of the necessary linear range and elimination of interferences from the blood. The slow penetration of enzyme‐based biosensors into clinical chemistry analysis is due to the fact that it is difficult to develop sensors which meet the high accuracy and reliability requirements, are manufacturable, and have an acceptable shelf life. The number of commercial products utilizing enzyme‐based biosensors will probably remain limited in the future due to the limited number of analytes for which a suitable enzyme exists. and for which the use of an enzyme‐based biosensor offers the advantages that can justify the costs of development.
Optical sensors for clinical monitoring
Authors: LÜBBERS D. W.
Published: January 2009

Technical progresses make it now possible to monitor well known or new parametersin vivoor in the laboratory with high accuracy. Especially optical sensors can advantageously be used for many medical applications. To understand advantage and limitation of a measuring technique the basic processes will be shortly discussed. There are two types of optical sensors: 1) optical sensors which use intrinsic indicators (as for example haemoglobin or cytochromes). In this chapter tissue photometry and evaluation methods for multicomponent scattering systems are discussed; nearinfrared and NADH fluorescence measurements are shortly mentioned. 2) Optical sensors using extrinsic indicators (optodes). As extrinsic indicators absorbant as well as luminescent indicators are used. Luminescence indicators are especially sensitive. Microoptodes and two dimensional imaging is possible. From the basic molecular reactions of the sensing mechanisms follows that for most of the indicator reactions there is a non‐linear, almost hyperbolic relationship between optical signal and concentration of the analyte. Consequently, accuracy as well as sensitivity of the optode is changing in a given measuring range. Therefore, the optical indicator must be carefully selected. Lifetime (or phase angle) measurements have the advantage that their accuracy is independent of indicator concentration, intensity of the light source and light transport between the sensing element and the photometric setup. Optodes can be manufactured as flexible membranes permeable for the analyte. This facilitates the construction of fibreoptic sensors. As practical examples oxygen optodes, ion optodes, opticalpCO2sensors, and bench‐top as well as intra‐arterial blood gas measurements are discussed in detail.
Experience with invasive and non‐invasive sensors for anaesthesia
Authors: ROLFE P.
Published: January 2009

This paper reviews experiences with the development and clinical use of invasive and non‐invasive sensors for continuous real‐time monitoring. The clinical focus, and inspiration, for this work has been the fetus and the newborn baby, but the work described is also directly relevant to the challenges of performing timely assessments of blood gas and acid‐base status in subjects undergoing anaesthesia and critical care. The first results obtained from the use of invasive PO2, PCO2, and pH sensors in humans, in the late 1960's. provided exciting new insights in to basic physiological processes, but the sensors were very limited in their performance, particularly with regard to haemocompatibility. Research since that time has been concerned with attempting to overcome the problems of blood interactions with sensor surfaces, and an approach based on the mimicry of cell membrane phospholipid biochemistry is described here. The issue of haemocompatibility may be obviated by the utilisation of non‐invasive methods. The interrogation of tissues by near infra‐red radiation (700–1000 nm) is described, with particular emphasis on the development of spectrophotometric technques for the measurement of HHb, HbO2, and Hb101 in the brain. Prospects for the measurement of other species, such as glucose, and of achieving spatial discrimination within tissues are also considered.
Oxygen parameters of arterial and mixed venous blood, ‐ new and old
Authors: SIGGAARD‐ANDERSEN OLE , GøOSTHGEN IVAR H.
Published: January 2009

A complete pH and blood gas analysis of arterial and mixed venous blood may comprise more than forty different quantities. We have selected sixteen, including patient temperature. The arterial oxygen tension group includes the oxygen tension, fraction of oxygen in inspired air, and fraction of mixed venous blood in the arterial (total physiological veno‐arterial shunting). The haemoglobin oxygen capacity group includes effective haemoglobin concentration and fractions of carboxy‐ and methaemoglobin. The haemoglobin oxygen affinity group includes half‐saturation tension and estimated 2,3‐diphosphoglycerate concentration of erythrocytes. In a neonatal care unit fraction of fetal haemoglobin need to be included. The arterial oxygen extractivity is measured as the oxygen extraction tension, which indicates the degree of compensation among the oxygen tension, capacity, and affinity. The mixed venous group includes mixed venous oxygen tension, and, when measured, cardiac output, and oxygen consumption rate. The acid‐base status includes blood pH, arterial carbon dioxide tension, and extracellular base excess. Other quantities such as haemoglobin oxygen saturation, respiratory index, total oxygen concentration (oxygen content), oxygen extraction fraction, oxygen delivery, and several others, seem to be redundant.
Desflurane and sevoflurane in adult day surgery
Authors: KORTTILA KARI
Published: January 2009

In 1994 66 per cent of all surgery in the United States was performed as ambulatory surgery. Day surgery is also expanding to other countries world‐wide. Desflurane and sevoflurane need to compete with propofol as general anaesthetics of choice for day surgery. Awakening and early recovery are faster after desflurane and sevoflurane than after propofol but postoperative nausea and vomiting appears to be more common after these two gases than after propofol. It remains to be seen if desflurane and sevoflurane will further improve outcome of day surgery by providing fast exit and early return to normal daily activities.
Fifty years of muscle relaxants
Authors: BEVAN D. R.
Published: January 2009

The introduction of curare improved surgical relaxation and encouraged anaesthetists to enlarge their vision. They became interested in the pharmacologic properties of their drugs and the physiologic changes associated with paralysis, and this led naturally to their involvement in intensive care and respiratory physiology. Since 1942, more than 50 muscle relaxants have been introduced: the current emphasis is on the short‐ to intermediate‐ duration agents that allow rapid recovery and avoid the problems associated with residual curarization, but we still await a nondepolarizing replacement for suxamethonium.
Pharmacokinetics and pharmacodynamics of the benzylisoquinolinium muscle relaxants
Authors: HULL C. J.
Published: January 2009

The benzylisoquinolinium class of drugs comprises atracurium, 51W89, doxacurium, and mivacurium. Atracurium can be used as a pharmacokinetic benchmark; it has at least two distinct metabolic pathways, of which Hofmann elimination and ester hydrolysis are the most significant. The relative importance of each of these two routes is still a matter of speculation, and this, coupled with the fact that atracurium is a mixture of 10 isomers, has led to the development of many innovative pharmacokinetic modelling concepts. 51W89 is a cis‐cis‐isomer of atracurium and probably has a pharmacokinetic profile very similar to that of atracurium. Doxacurium, a long‐acting benzylisoquinolinium, has a small apparent volume of distribution and an elimination half‐time similar to that of pancuronium, and is excreted by the kidneys. Mivacurium is a short‐acting benzylisoquinolinium that is rapidly hydrolysed by plasma cholinesterases. Two isomers of mivacurium are very similar, whereas the third isomer differs greatly in both pharmacological activity and elimination half‐time, so that analysis requires complex pharmacokinetic methods.
The clinical and basic pharmacology of mivacurium: a short‐acting nondepolarizing benzylisoquinolinium diester neuromuscular blocking drug
Authors: SAVARESE J. J. , LIEN C. A. , BELMONT M. R. , RUBIN L.
Published: January 2009

Mivacurium is a benzylisoquinolinium diester. The drug is a nondepolarizing relaxant which is hydrolysed by plasma cholinesterase at 70–88% of the rate of suxamethonium. Enzymatic hydrolysis gives the drug its short duration of action. The length of paralysis is about 2‐2.5 times that of suxamethonium and one‐half to one‐third that of the intermediate‐acting nondepolarizers. The development of mivacurium represents a collaboration between industrial pharmacologists and chemists at Burroughs Wellcome Co. (USA) and investigators at the Massachusetts General Hospital, Boston, MA, USA.
Intubating conditions and neuromuscular effects of mivacurium during propofol‐alfentanil anaesthesia
Authors: VAN AKEN H. , ORY J.‐P. , VANDERMEERSCH E. , VERTOMMEN J. D. , CRUL J. F.
Published: January 2009

In three groups of 20 patients, anaesthetized with propofol and alfentanil, tracheal intubation conditions and the onset of neuromuscular blockade after administration of three different doses of mivacurium chloride (0.11, 0.15, and 0.19 mg/kg=1.5×ED95 2.×ED95, and 2.5×ED95) were assessed. Intubation conditions were found to be clinically acceptable (good or excellent) in 83% of patients. Eighty‐two per cent of patients were successfully intubated on the first attempt after 60–90 s. No difference in intubation scores or number of intubation attempts among the three dosage groups were found. We conclude that mivacurium chloride allows smooth intubation in most patients within 60 90 s, even with the lowest dose (0.11 mg/kg), after a propofol‐alfentanil induction of anaesthesia. However, because there were a few patients in whom intubating conditions were inadequate at 60–90 s, we are reluctant to advocate the preference of mivacurium chloride over suxamethonium for rapid sequence induction in emergency situations.
Mivacurium in short to intermediate surgical procedures
Authors: PLATT M. W.
Published: January 2009

Mivacurium, a new benzylisoquinoline muscle relaxant, appears to be close to the ideal for short to intermediate surgical procedures. Ideal properties of such an agent are discussed, in addition to indications for muscle relaxation in such procedures. Two studies are presented, showing the onset and offset times of mivacurium and its cardiovascular stability in both young and elderly patients. It is concluded that it is a well‐tolerated and appropriate agent for use in short to intermediate surgical procedures in those patients with normal plasma cholinesterase function, despite a slight prolongation of action in the elderly.
Mivacurium chloride in infants and children
Authors: MERETOJA O. A. , TAIVAINEN T.
Published: January 2009

Mivacurium has been little studied in infants and children without a volatile anaesthetic agent. We analysed onset time and maximal neuromuscular response after mivacurium 0.1 mg/kg, and the infusion requirement of mivacurium to maintain a 50, 90, or 95% neuromuscular block in 76 infants and children under N2O‐O2 alfentanil anaesthesia. Furthermore, we assessed the time course of potentiation of 1 MAC end‐tidal halothane or isoflurane on the infusion requirement of mivacurium. Neuromuscular response was recorded by adductor pollicis electromyogram. The onset time of mivacurium was shorter in infants than in children (2.1 ± 0.6 and 3.2 ± 0.9 min (mean±SD); P=0.0001). The dose potency of mivacurium did not depend on the age of a paediatric patient. The estimated ED95 of mivacurium was 136±46 μg/kg. The mivacurium requirement to maintain a 50, 90, or 95% neuromuscular block averaged 340, 730, and 900 μg/kg/h, respectively. Halothane and isoflurane decreased this hourly requirement by 35 and 70%, respectively. The decrease in the mivacurium infusion requirement was fastest in the youngest children. In conclusion, mivacurium is easy to administer as bolus doses or continuous infusion in paediatric patients because its potency is similar in all patients from 1 month to 15 years of age. Halothane and isoflurane produce their maximal potentiation of neuromuscular block only after 30–60 min of administration. This potentiation is similar in magnitude in all patients, but takes place fastest in the youngest children.
Mivacurium in special patient groups
Authors: JONES R. M.
Published: January 2009

In special patient groups, drug response may be different from that in the healthy adult patient. Mivacurium dose requirements vary with age, and children require larger doses to obtain any given degree of block, but the elderly often require smaller doses. However, the dose requirements of the neonate do not necessarily differ greatly from those of the adult. There is a relationship between the duration of action of a bolus dose – as well as infusion requirements to maintain block – and the plasma cholinesterase activity. Patients with renal disease may have a decreased cholinesterase activity and may require smaller doses of mivacurium. Patients with severe liver disease may have a marked decrease in cholinesterase activity, and in these patients a substantially smaller dose of the drug may be needed to obtain and maintain any given degree of block. If the variation in dose requirements is kept in mind and the degree of block appropriately monitored, mivacurium may be used with safety in special patient groups, such as children, the elderly, or those with renal or hepatic impairment.
The role of muscle relaxants in total intravenous anaesthesia
Authors: POLLARD B. J.
Published: January 2009

For total intravenous anaesthesia (TIVA), all drugs that are required as part of the anaesthetic method are administered intravenously. This is usually taken to imply the use of intravenous infusions. It is normal practice to administer muscle relaxants intravenously, although other routes have been used. A muscle relaxant is required firstly to secure paralysis and secondly to maintain paralysis. The rate of onset of all the nondepolarizing neuromuscular blocking agents which are routinely available at present is similar; it takes about 3–6 min for a normal clinical dose to reach maximum effect. Maintenance of an adequate level of block is necessary, and it is usually helpful to the surgeon for the level of block to be relatively constant. The choice of drug is important. It should cause negligible side‐effects. For administration by infusion, an agent with an intermediate (e. g., atracurium) or short (e. g., mivacurium) duration of action is essential to ensure a rapid recovery of effect on termination of the infusion. The routine use of neuromuscular monitoring is recommended when a continuous infusion of a relaxant is used.
The use of neuromuscular blocking drugs in intensive care practice
Authors: ELLIOT J. M. , BION J. F.
Published: January 2009

Critically ill patients represent a very different population from that of the operating theatre, but much of our knowledge of many of the neuromuscular blocking drugs is derived from intraoperative use. The diversity of clinical‐practice and case‐mix differences in intensive care are probably responsible for the absence of a formal consensus about the use of neuromuscular blocking drugs in the intensive care unit (ICU). Various surveys suggest that these drugs are used comparatively infrequently, but we do not know whether current usage is either safe or appropriate. In addition to the adverse effects which inevitably accompany prolonged paralysis and immobility, the steroidal relaxants, pancuronium and vecuronium, have also been associated with myopathy. This seems to be aggravated by concurrent use of pharmacologic doses of corticosteroids or the aminoglycoside antibiotics. Neither the mechanism nor the validity of the association with steroidal relaxants is known at present. Muscle dysfunction is a common feature of critical illness, and it is possible that neuromuscular blocking drugs interfere with muscle repair and regrowth. Patients with multiple organ failure present a particular challenge both because of the extent of tissue injury and because drug clearance via the liver or kidneys is generally impaired.
The future of the benzylisoquinolinium relaxants
Authors: SAVARESE J. J. , WASTILA W. B.
Published: January 2009

The benzylisoquinolinium relaxants currently include the intermediate‐acting agent, atracurium, and the short‐acting agent, mivacurium. This class of relaxants has always retained the distinct advantages of rapid degradation, enzymatic metabolism, or both in the plasma, resulting in short half‐lives and fast, complete recovery, unrelated to dose or duration of administration. Any improvements in this class of relaxants must focus on retaining this property at the same time as decreasing or eliminating histamine release, which has always been the major disadvantage of the benzylisoquinoliniums. The introduction of 51W89, an isomer of atracurium, may represent an advance in the development of this class of relaxants.
Oxygen and acid‐base parameters of arterial and mixed venous blood, relevant versus redundant
Authors: SIGGAARD‐ANDERSEN O. , GøTHGEN I. H.
Published: January 2009

A complete pH and blood gas analysis of arterial and mixed venous blood may comprise more than forty different quantities. We have selected sixteen, including patient temperature. The arterial oxygen tension group includes the oxygen tension, fraction of oxygen in inspired air, and fraction of mixed venous blood in the arterial (total physiological veno‐arterial shunting). The haemoglobin oxygen capacity group includes effective haemoglobin concentration and fractions of carboxy‐ and methaemoglobin. The haemoglobin oxygen affinity group includes half‐saturation tension and estimated 2, 3‐diphosphoglycerate concentration of erythrocytes. In a neonatal care unit fraction of fetal haemoglobin needs to be included. The arterial oxygen extractivity is measured as the oxygen extraction tension, which indicates the degree of compensation among the oxygen tension, capacity, and affinity. The mixed venous group includes mixed venous oxygen tension, and, when measured, cardiac output, and oxygen consumption rate. The acid‐base status includes blood pH, arterial carbon dioxide tension, and extracellular base excess. Other quantities such as haemoglobin oxygen saturation, respiratory index, total oxygen concentration (oxygen content), oxygen extraction fraction, oxygen delivery, and several others, provide no essential additional clinical information and are therefore redundant.
A maximal central venous oxygen saturation (SvO2max) for the surgical patient
Authors: JENSTRUP M. , EJLERSEN E. , MOGENSEN T. , SECHER N. H.
Published: January 2009

Before induction of anaesthesia, 23 patients scheduled for major abdominal surgery had blood samples drawn from a central venous catheter for oxygen saturation (SvO2) after graded infusion of isotonic saline. The infusion of saline was continued until further administration resulted in a stable SvO2 (SvO2max). The SvO2 increased from 69 (53–83) to 72 (66–83) % (median and range; P < 0. 0001), when the patients received 10 (0–26) mL‐ kg‐1, average 500 mL, of saline. At the same time central venous haematocrit decreased from 38 (32–47) to 36 (23–47) % which suggests that the intravascular volume was expanded by 420 (180–3070) mL or by 72 (18–174) % of the administered volume. The results demonstrate that volume expansion by saline can establish a maximal venous oxygen saturation in the surgical patient.
The influence of Patent Blue V on pulse oximetry and haemoximetry
Authors: LARSEN V. H. , FREUDENDAL‐PEDERSEN A. , FOGH‐ANDERSEN N.
Published: January 2009

Patent Blue V (PBV) is a blue dye solution which is used to visualize lymphatic vessels for surgical procedures. There has been some conflicting reports about the influence of this dye solution on pulse oximetry and haemoximetry, why we decided to: 1) produce a spectrum of PBV in plasma, 2) measure absorbances of full blood before and after addition of PBV and 3) to record the effect on the pulse oximeter and haemoximeter of an intradermal injection of PBV to a patient. Computer analysis of the blood gas measurements were carried out by the Oxygen Status Algorithm (OSA). The spectrum of PBV demonstrated a peak absorption at 640 nm and correspondingly the absorbances of the haemoximeter increased most significantly at 622 and 636 nm. These changes invalidated the determination of haemoglobin pigments, and the results should not be used. Computer analysis interpreted the measurements as a shift of the haemoglobin oxygen binding curve.
A simple quality control protocol for haemoximetry using standard p50
Authors: MORGAN J. , CLAGUE A. , RAYFIELD J. , ENDRE Z.
Published: January 2009

We have designed a quality control tool for haemoximetry using the principle that standard p50, calculated from blood gas and haemoximetry measurements using the Siggaard‐Andersen algorithm, remains unchanged when a specimen of venous blood is oxygenated progressively to 97% saturation of haemoglobin. If the haemoximeter is inaccurate, progressively larger deviations of standard p50 from the constant value occur above 80% saturation. Deviations too small to be detected by analysis of quality control materials comprised of non‐haemoglobin dyes and yet sufficient to cause significant errors in derived extractivity parameters can be detected by this method.

The suggested protocol is easy to perform, and is recommended as a quality control tool for blood gas analyser/haemoximeters used to determine arterial extractivity parameters.
French national quality control for pH and blood gases: Ten years experience
Authors: FEUILLU A.
Published: January 2009

A national quality control program for blood gas analysers has been established in France since 1983. Buffer solutions are used at two levels of pH, Po2, Pco2 for testing 950 laboratories using 22 different models. These annual programs inform about the accuracy and the precision of the instruments. They also make the user conscientious to different procedures of quality control. Information is also obtained on the yearly turnover of the types of analysers.
The accuracy of a fiberoptic oximeter over a wide range of arterial oxygen saturation values in piglets
Authors: NIJLAND R. , JONGSMA H. W. , NlJHUIS J. G. , OESEBURG B.
Published: January 2009

A piglet model was used to evaluate the accuracy of a fiberoptic oximeter over a wide range of arterial oxygen saturation (SaO2) values. In eight anaesthetized piglets, the inspired oxygen concentration was varied from 30% to 6% resulting in a SaO2 range from 100% to 15%. Paired data of the Opticath® fiberoptic catheter, which was placed in the descending aorta, and blood sample SaO2 values assessed by a multiwavelength oximeter, were analysed. After in vitro calibration according to the manufacturer's instruction, the fiberoptic catheter started to underestimate the SaO2 below 78%, worsening towards lower SaO2 values. The overall bias was ‐3. 4% and the precision 3. 8%. An off‐line fit with a non‐linear model resulted in a standard deviation of residuals of 2. 6%. After several in vivo calibration adjustments when the Fiberoptic oximeter deviated more than 4% from the blood sample value, the bias was eliminated over the total SaO2 range and the precision was 3. 7%. The Opticath® fiberoptic oximeter could have an accuracy for the whole SaO2 range between 15–100% close to the accuracy of the multiwavelength oximeter, when the fiberoptic oximeter is adapted for the underestimation below 78% SaO2.
Oxygraphy in spontaneously breathing subjects
Authors: LARSEN V. H. , WALDAU T. , ØBERG B.
Published: January 2009

Background: Continuous monitoring of O2 and CO2 in the airways of spontaneously breathing patients can be carried out by sampling air to a gas monitor through a catheter placed in the upper airway. The graphical display of O2 (oxygraphy) is a rather new facility.

Objective: To describe the photo‐acoustic and magneto‐acoustic technique for CO2 and O2 monitoring in the open unintubated airway, to evaluate the efficacy of oxygen therapy by oxygraphy and to determine alveolar gas tensions and alveolar‐arterial partial pressure gradients.

Data sources: O2 and CO2 fractions in the airways were monitored in 9 healthy subjects. Blood samples were drawn from the radial artery.

Methods: The Multigas Monitor 1304 (Brüel and Kjær, Naerum, Denmark) was used; end‐expiratory measurements were considered as representative for the alveolar gas composition. Arterial blood was analysed by ABL™520 (Radiometer Medical A/S, Copenhagen, Denmark).

Results: Reliable tracings of gas fractions (FCO2 and FO2) were obtained during the respiratory cycle in all subjects. When oxygen was supplied, FO2 of the airway varied considerably during the inspiratory phase whereas it remained almost constantly during the expiratory phase. The end‐expiratory FO2 increased from 0. 15 breathing atmospheric air to 0. 41 breathing oxygen 15 L/min through a Hudson mask. Alveolar‐arterial partial pressure differences were: pO2(A‐a): 1. 07 ± 0. 85 kPa and pCO2(A‐a): ‐0. 04 ± 0. 33 kPa during norrnoventilation in atmospheric air.

Conclusion: Continuous monitoring of CO2 and O2 in the airway gives information about the pulmonary gas exchange and the efficacy of oxygen supply. Combined with arterial blood gas analysis the method allows determination of alveolar‐arterial CO2 or O2 gradients.
Measurements of sodium and potassium in newborns and prematures by ion‐selective electrodes and flame photometry: Influence of lipid and protein content of blood
Authors: KAU N. , GÜNTHER M. , FAHNENSTICH H. , KOWALEWSKI S. , BARTMANN P.
Published: January 2009

The alternative use of flame photometry and ion selective electrodes for electrolyte determinations in neonatology led to the question how the two methods agree. 104 routine blood samples were taken as matched pairs for a comparison of sodium and potassium determinations. Pre‐analytical error was avoided by the mode of blood collection. The influence of the protein and lipid content of blood on the differences between the methods was determined by calculating its water content and making a post‐correction of the flame values. Thus the differences for sodium could be reduced, whereas the differences for potassium slightly increased.

As long as the imprecision of sodium determination is a meaningful methodological problem, the influence of the protein and lipid content of neonatal blood is not the main factor for differences between ISE and flame photometry.
Computerized form of Siggaard‐Andersen's double chart
Authors: JABOR A. , HORÁČEK M.
Published: January 2009

A description of the computer program IEFPlus is given. The program is based on the sodium‐potassium double chart for classification of salt‐water disturbances presented by Siggaard‐Andersen.

Input variables of the program are: 1. the concentration of sodium in the plasma, representing the sodium concentration in the Ecf, 2. the relative potassium deficit or excess in the Icf, estimated on the basis of the plasma potassium concentration and the blood pH, and 3. the total water excess or deficit in the body estimated on the basis of the change in body weight.

Output variables are: 1. the sodium excess or deficit in the Ecf, and 2. the volumes of the Ecf and Icf (and/or the changes in either one). This simple model is displayed in one screen showing the values of all the essential parameters many of which can be easily changed. A graphic display of the Icf and Ecf volumes is also given. IEFPlus enables the user to predict the effect of sodium and water administration. Similarly the effect of renal or extrarenal water and sodium losses can be taken into account.
Classes of tissue hypoxia
Authors: SlGGAARD‐ANDERSEN O. , ULRICH A. , G0THGEN I. H.
Published: January 2009

We identify eight causes of tissue hypoxia, falling into three classes, A, B, and C, depending upon the effect on the critical mixed venous pO2 and the optimal oxygen consumption rate. The critical mixed venous pO2 is the value above which the oxygen consumption rate is optimal and independent of the mixed venous pO2 and below which the oxygen consumption rate decreases towards zero. Class A hypoxia: primary decrease in mixed venous pO2. Causes: 1) ischaemic hypoxia (decrease in cardiac output), 2) low‐extractivity hypoxia (decrease in oxygen extraction tension, p8). Class B hypoxia: primary increase in critical mixed venous pO2. Causes: 1) shunt hypoxia (increased a‐v shunting), 2) dysperfusion hypoxia (increased diffusion length from erythrocytes to mitochondria and/or decreased total capillary endothelial diffusion area, e. g., tissue oedema, microembolism), 3) histotoxic hypoxia (inhibition of the cytochrome chain). Class C hypoxia: primary increase in optimal oxygen consumption rate. Causes: 1) uncoupling hypoxia (uncoupling of the ATP formation associated with O2 reduction), 2) hypermetabolic hypoxia (increased energy metabolism, e. g., due to hyperthermia).
Mitochondrial dysfunction in ischaemia‐reperfusion
Authors: SARIS N.‐E. L. , ERIKSSON K. O.
Published: January 2009

The mitochondrial dysfunction in ischaemia‐reperfusion is shortly reviewed. During ischaemia the ATP level and pH drops, phospholipids are degraded, membrane permeabilities increased and the cytosolic levels of Na+ and Ca2+ raised. During the following reperfusion the Ca2+ levels may further increase while pH is raised. The oxidative phosphorylation is resumed and the ATP used for membrane repair and ion pumping. The mitochondrial Ca2+ handling is important in removing Ca2+ from the cytosol since the mitochondria are able to take up substantial amounts of Ca2*. However, if a certain threshold is exceeded, mitochondria undergo a so‐called permeability transition (MPT), release their Ca2+, undergo swelling and become uncoupled. MPT has been shown to be due to the opening of large pore allowing passage of substances with a M8 <1500. Data are presented showing by electron microscopy swelling of mitochondria in cells in perfused liver before other gross morphological changes have taken place.

There are a number of factors lowering the threshold for Ca2+ in inducing the MPT: inorganic phosphate, prooxidants that oxidize membrane SH‐groups, oxidation of NAD(P)H and GSH, while a protective effect is exerted by Mg2+, ADP (and ATP), some antioxidants, carnitine, decrease in pH, and cyclosporin A that binds to cyclophilin. The potential benefit of these in minimizing reperfusion‐induced tissue damage is discussed.
Hypothesis: Angiogenesis cytokines in high altitude cerebral oedema
Authors: SEVERINGHAUS J. W.
Published: January 2009

Abstracted from Severinghaus J W. Hypothetic roles of angiogenesis, osmotic swelling and ischemia in high altitude cerebral edema. J Appl Physiol 1995: (in press).
Effect of casein‐based semi‐synthetic food on renal acid excretion and acid‐base state of blood in dogs
Authors: ZIJLSTRA W. G. , LANGBROEK A. J. M. , KRAAN J. , RISPENS P. , NIJMEIJER A.
Published: January 2009

Urinary acid excretion and blood acid‐base state were determined in dogs fed a casein‐based semi‐synthetic food (SSF), to which different amounts of salts had been added, in comparison with feeding normal dog food. Net acid excretion (NAE) and inorganic acid excretion (IAE) increased during SSF feeding. IAE was higher than the acid load calculated from the sulphur and phosphorus content of the casein. This higher IAE appeared to be due to the presence of calcium and magnesium phosphate in the diet, because calcium and magnesium may be in part precipitated as carbonate, leaving phosphate to be absorbed as phosphoric acid. Acid excretion decreased by addition of CaO. When no neutral Na+ and K+ salts were added, the increase in NAE was accompanied by a metabolic acidosis. K+ was more effective in attenuating the acidosis than Na+. On the basis of these findings a diet can be made which imposes a known acid load, and provides stable baseline values. Hence, any additions that influence the acid‐base balance can be properly studied. The data obtained in these and future studies utilising this diet may be of help in optimising the composition of nutrient solutions to be used in the care of critically ill patients.
How far can we go with permissive hypercapnia? A case presentation and some biased comments with emphasis on maintaining normal haemoglobin level
Authors: OHMURA A. , SHA M. , KATAGIRI J.
Published: January 2009

The respiratory management strategy of small tidal volume with permissive hypercapnia has been adopted to avoid further aggravation of lung injury due to high airway pressure with some impressive success (1). No consensus, however, has been established in terms of the rate of increase in PaCO2 and its upper limit. Recently, our colleague in the intensive care unit experienced a severe case of ARDS successfully treated with the above strategy despite of the fact that during the course of treatment, the highest PaCO2 reached 177 mmHg and the lowest pH, 7. 03 (2). The fact that PaCO2 may reach a very high level in the clinical setting and the well‐known role of haemoglobin (Hb) in buffering CO2 led us to study effects of different Hb levels on pH and haemodynamic changes in response to acute CO2 loading in the blood. We will summarize the case report first with permission of authors (the case report was published in Japanese) (2) and then discuss the studies conducted in our animal laboratory.
Which blood gas caused the brain damage?
Authors: SUWA K.
Published: January 2009

In order to analyse the effects of various physiological parameters including blood gas data on the cerebral oxygenation, we developed a model to enable us to estimate PtO2 (tissue PO2) from these physiological parameters. This model was applied successfully to a set of blood gas data of a patient who had brain damage after cardiac surgery. Contrary to the original impression, we concluded that a very low PaCO2 of 13 mmHg towards the end of CPB was the most likely cause of his damage.
Homeostasis‐securing therapy and statusmetria
Authors: SHIFRIN G. A.
Published: January 2009

Statusmetria allows to define the effective levels of oxygen status. The conception of Syndrome Intensive Care (SIC) has exhausted itself and invariable outcomes of SIC of Multiorgan System Failure (MOSF) confirms that. Therefore, an alternative to SIC should be advanced. Efficiency of treatment has been assessed in 257 patients with MOSF using values of metabolic rate and ability of the organism to cover it by oxygen and substrate supply. Oxygen Pulse (OP) and Index of Efficacy of Oxygen Transport (IETO2) were monitored. Intensive care was considered to be Homeostasis‐Securing Therapy (HST) if the energostructure deficit was eliminated and the necessary recovery of regeneration rate was restored. OP in patients with MOSF was 0. 8 mL m‐2 or less and IETO2 was 2. 4 units in SIC. We managed to maintain an OP of 1. 0–1. 7 mL m‐2 and an IETO2 of 1. 9–2. 4 units in HST. 41 patients out of 135 with MOSF survived in SIC and 96 patients out of 122 survived in HST. The efficiency of HST appeared to be twice as much as the efficiency of SIC. Conception of homeostasis‐securing therapy is advancing. The conception provides restoration of regeneration rate due to the effective elimination of energostructure deficit compared to SIC. The concept may be a basis of a new technology for the treatment of MOSF.
Flumazenil and midazolam in anaesthesia
Authors: WHITWAM J. G.
Published: January 2009

Flumazenil, the first benzodiazepine antagonist, is currently used widely as an emergency drug, and has also been utilized in planned procedures, to time arousal intra‐ or post‐operatively. It is known that flumazenil, used at the end of a procedure, causes instant recovery by reversing the residual effects of, for example, midazolam. An agonist‐antagonist concept, midazolam‐flumazenil, where benzodiazepine sedation or anaesthesia is terminated at will, is, therefore, finding increasing application. In neuroanaesthesia, for example, it facilitates immediate recovery, cardiovascular stabilization and the use of midazolam as an alternative to thiopentone and inhalational agents, and in ear, nose and throat endoscopies, it permits more rapid turnover of patients and is a good choice for haemodynamic stability in patients with a high cardiovascular risk factor. There continues to be debate over the term used to describe the level of sedation remaining after the effects of the antagonist have worn off. ‘Resedation’ is often used incorrectly to describe what is in reality residual sedation. Given the correct use of midazolam or the exploitation of synergism using opioids, flumazenil will cause arousal, while maintaining the benefit of opioid analgesia. Such a technique may eliminate the need for formal recovery facilities in many ambulatory patients, thereby reducing dependence on trolleys, beds and nurses. This has major implications for health economics, particularly in relation to endoscopy clinics and when co‐induction of anaesthesia is employed.
The role of flumazenil in the critically ill
Authors: PARK G. R. , NAVAPURKAR V. , FERENCI P.
Published: January 2009

Flumazenil is a specific benzodiazepine antagonist. It competitively inhibits the action of benzodiazepines at gamma aminobutyric acid (GABA) receptors in the central nervous system and thus reverses the sedative effects of benzodiazepines. Usually, it is given intravenously as a bolus dose or as an infusion. It has a short duration of action. Flumazenil is extensively metabolized to compounds that have minimal benzodiazepine antagonistic properties. Reversal of sedation can be useful in many conditions that are often encountered in the critically ill. The adverse effects of its use are usually predictable and, with sufficient clinical monitoring, are usually avoidable. These properties make it a useful and safe drug when used appropriately.
Amrinone reverses bupivacaine‐induced regional myocardial dysfunction
Authors: Fujita Y.
Published: January 2009

Amrinone has been shown to have therapeutic effects on bupivacaine‐induced cardiovascular toxicity, but its exact effects on the heart are not well understood.

This study evaluated the regional myocardial effect of amrinone on bupivacaine‐induced cardiovascular toxicity inin situbeating hearts in 10 dogs using a selective coronary perfusion and sono‐micrometry. In the control group, bupivacaine was administered into the left anterior descending coronary artery (LAD) for 15 min at tour steps: baseline, step 1, step 2 and step 3, (calculated LAD plasma concentrations; 0, 5, 5 and 10 μg·ml‐1, respectively). In the amrinone group, amrinone (5 μg·ml‐1) was simultaneously infused at steps 2 and 3 in addition to bupivacaine infusions. Regional myocardial function of the LAD supplied area was evaluated by analysis of the left ventricular pressure‐segment length loop.

In the control group, systolic shortening decreased from the baseline (10.5±1.3%, mean ± SEM) to step 3 (0.1±1.3%), and post‐systolic shortening increased from the baseline (18.0±3.7%) to step 3 (52.3±5.5%) dose‐dependently. In contrast, with amrinone infusion at steps 2 and 3, both variables returned to near baseline values.

These results indicate that amrinone reverses bupivacaine‐induced regional myocardial dysfunction.
Influence of anesthetic technique on early postoperative hypoxemia
Authors: Georgiou L. G. , Vourlioti A. N. , Kremastinou F. I. , Stefanou P. S. , Tsiotou A. G. , Kokkinou M. D.
Published: January 2009

In the present study we have compared the incidence and degree of hypoxemia during the early postoperative period and for the first 3 nights after operation occuring after the administration ot total intravenous anesthesia with propofol versus inhalation anesthesia with nitrous oxide and isoflurane.

We studied 50 consecutive non‐obese patients, ages 25–65, ASA I‐11, who were scheduled for elective cholecystectomy. Patients received randomly either total intravenous anesthesia with propofol (24 patients) or inhalation anesthesia with nitrous oxide and isoflurane (26 patients). Oxygen saturation was continously recorded on the night before surgery, for 8 hours after extubation (early postoperative period) and during the first, second and third nights after operation.

In the early postoperative period we found statistically significant higher values of mean (P<0.05) and minimum (P<0.01) SpO2 in patients who received total intravenous anesthesia compared to patients in whom inhalation anesthesia was used. Moreover, in the early postoperative period, 4 (16.7%) patients of the intravenous anesthesia group versus 11 (42.3%) patients of the inhalation anesthesia group had at least 1 hypoxemic event (P<0.05).

We conclude that the incidence and degree of hypoxemia in the early postoperative period is significantly less when total intravenous anesthesia with propofol is used.
Effects of pH and buffer capacity modulation on the analgesic efficacy of lignocaine and pethidine solutions
Authors: Dyhre H. , Wallin R. , Renck H.
Published: January 2009

Background.Objectives were to study the effects of variations in the pH and the buffer capacity of solutions of lignocaine or pethidine on their analgesic efficacy in peripheral nerve block.

Methods.Infraorbital nerve blocks (IONB) were induced in rats during light pentobarbitone anaesthesia employing 0.2 ml of test solutions containing 10 mg · ml‐1of lignocaine or pethidine dissolved in normal saline, 50 mmol and 150 mmol tris‐hydroxymethylaminomethane (THAM) hydrochloride (THAM · HCI) of pH 4.8 and 4.5, respectively, or 100 mmol THAM‐THAM · HCI of pH 7.4. The pH of solutions in saline was varied from 3.0 to 9.3 by adding HCI or NaHCO3. The analgesic efficacy is expressed as the interval from injection to elicitation of a minimal response to electric stimulation at various intensities (threshold intensities) within the blocked area (IONB 3 to 10), and in terms of the area under the curve (AUC, threshold intensitiesvs.time).

Results.When dissolved in saline, pH 7.4, pethidine exerted more pronounced effects than lignocaine [AUC by 3.5 times (P<0.001), IONB 3 to 10 by 2.7 (P<0.05) to 3.6 (P< 0.001) times]. Variations of the pH of solutions did not affect their analgesic efficacy. Lignocaine exerted more pronounced local analgesic effects when mixed with 150 mmol THAM · HCI than when mixed with saline (pH 7.4), but manifested even more pronounced effects when dissolved in THAM+THAM · HCI [AUC by 3.7 times (P<0.001), IONB 3 to 10 by 2.7 (P0.01) to 3.8 (P<0.001) times]. When dissolved in THAM+THAM · HCI, the analgesic efficacy of pethidine increased by 2.0 to 2.8 times (P<0.001), as compared to a solution in saline at the same pH.

Conclusions.It is concluded that variations in the pH of solutions of lignocaine or pethidine in saline does not affect the analgesic efficacy of the drugs, presumably due to the low buffer capacity of the medium, whereas when dissolved in THAM+THAM · HCI · their effect is enhanced.