bluuebunny/crossref_metadata_2025 huggingface dataset:
Prospective Observational Study of Emergency Airway Management in the Critical Care Environment of A Tertiary Hospital in Melbourne
Authors: Dyett J. F. , Moser M. S. , Tobin A. E.
Published: January 2019

The objective of this study is to describe the population of patients receiving emergency airway management outside operating theatres at our institution, a tertiary referral centre in Melbourne. A registry of all patients receiving emergency airway management in the emergency department, ICU and on the wards as part of Medical Emergency Response teams’ care, was prospectively collected. There were 128 adults and one paediatric patient requiring emergency airway management recruited to the study. Data for analysis included patient demographics, pre-oxygenation and apnoeic oxygenation, staff, drugs, details of laryngo-scopic attempts, adjuncts, airway manoeuvres, complications sustained and method of confirmation of endotracheal tube placement. Over a 12-month period, there were 139 intubations of 129 patients, requiring a total of 169 attempts. Respiratory failure was the most common indication for intubation. Intubation was successful on the first episode of laryngoscopy in 116 (83.5%) patients. Complications occurred in 48 patients. In the cohort of patients without respiratory failure, nasal cannulae apnoeic oxygenation significantly reduced the incidence of hypoxaemia (0 out of 31 [0.0%] versus 10 out of 60 [16.7%], P=0.016; absolute risk reduction 16.7%; number needed to treat: 6). Waveform capnography was used to confirm endotracheal tube placement in 133 patients and there were four episodes of oesophageal intubation, all of which were recognised immediately. In the critical care environment of our institution, emergency airway management is achieved with a first-attempt success rate that is comparable to overseas data. Nasal cannulae apnoeic oxygenation appears to significantly reduce the risk of hypoxaemia in patients without respiratory failure and the use of waveform capnography eliminates episodes of unrecognised oesophageal intubation.
Fluid Administration, Vasopressor Use and Patient Outcomes in a Group of High-Risk Cardiac Surgical Patients Receiving Postoperative Goal-Directed Haemodynamic Therapy: A Pilot Study
Authors: Walker L. J. C. , Young P. J.
Published: January 2019

The role of goal-directed therapy in high-risk cardiac surgical patients has not been determined. This study sought to observe the effect of a postoperative standardised haemodynamic protocol (SHP) on the administration of fluid and vasoactive drugs after high-risk cardiac surgery. This was an interventional pilot study. In 2010 to 2011, the SHP was introduced to the ICU at Wellington Regional Hospital, Wellington, New Zealand, for the perioperative management of patients undergoing high-risk cardiac surgery. A pulmonary artery catheter was inserted in the patients in the study group and fluids and supportive medications were provided in the ICU according to a protocol that targeted a cardiac index ≥2 l/min/m2, mixed venous oxygen saturation ≥60% and a mean arterial pressure of 65 to 75 mmHg. Data from 40 consecutive high-risk cardiac surgical patients assigned to this protocol were compared with a matched cohort of 40 consecutive high-risk cardiac surgical patients receiving ‘usual care’ in 2009. Baseline characteristics were similar in the two groups. There was no significant difference in the duration of noradrenaline infusion in the SHP cohort compared to historical controls (median [IQR] 18.5 hours [31.63] versus 18 hours [18.3]; P=0.35), despite patients receiving more fluid in their first 12 hours in the ICU (mean 4687 ml [SD±2284 ml] versus 1889 ml [SD±1344 ml]; P <0.001). The SHP cohort had a higher rate of reintubation (4 in 37 [10.8%] versus 0 in 40 [0%]; P=0.049). The SHP delivered significantly more fluid, but did not reduce the duration of noradrenaline infusion, compared to usual care.
Revalidation: Implications for Australian Anaesthetists
Authors: Roberts L. J.
Published: January 2019

In early 2015, the Medical Board of Australia commissioned research into international revalidation models and what might be applicable for Australia. This review examines the implications for Australian anaesthetists. What problem is revalidation seeking to address? What is happening in similar countries? Is there an issue with Australian anaesthetists’ performance? Isn't continuing professional development enough? Could the Medical Board target known high-risk doctors? What is the evidence for the benefit of revalidation? How is and how should the profession be involved? Revalidation has been introduced in other developed countries. It commonly involves continuing professional development, feedback from colleagues, co-workers and patients, clinical audit and peer review. Although its evidence base is limited, the General Medical Council in the United Kingdom is evaluating its revalidation system, which should provide useful guidance for other countries. Australian anaesthetists and their professional organisations must remain informed about, and engaged in, the national debate about revalidation, to ensure that any new process is workable for Australian anaesthesia practice.
Developments in Labour Analgesia and their use in Australia
Authors: Eley V. A. , Callaway L. , Van Zundert A. A.
Published: January 2019

Since the introduction of chloroform for labour analgesia in 1847, different methods and medications have been used to relieve the pain of labour. The use of heavy sedative medication in the early 1900s was encouraged by enthusiastic doctors and by women empowered by the women's suffrage movement in America. Nitrous oxide by inhalation has been used in Australia since the 1950s and improved methods of administration have made this method of analgesia safe and practical. Caudal epidural analgesia and lumbar epidural analgesia were first made popular in America and by the 1970s these techniques were more widely available in Australia. In 1847, physicians and the public were unsure whether relieving labour pains was the ‘right’ thing to do. However, many medical and social changes have occurred thanks to the clinical connection between Australia and the United Kingdom and those first settlers to land on Australian shores. Thanks to this historical connection, in today's Australia there is no question that women should use analgesia as a pain relief if they wish. Currently, the majority of women worldwide use some form of analgesia during labour and different methods are widely available. This paper discusses the four milestones of the development of obstetric analgesia and how they were introduced into patient care in Australia.
Pioneering Early Intensive Care Medicine by the ‘Scandinavian Method’ of Treatment for Severe Acute Barbiturate Poisoning
Authors: Trubuhovich R. V.
Published: January 2019

Between the 1920s and the mid-1950s, barbiturates were the sedative-hypnotic agents most used in clinical practice. Their ready availability and narrow therapeutic margin accounted for disturbingly high rates of acute poisoning, whether suicidal or accidental. Until the late 1940s, medical treatment was relatively ineffective, with mortality subsequently high – not only from the effects of coma, respiratory depression and cardiovascular shock with renal impairment, but also from complications of the heavy use in the 1930s and 1940s of analeptic stimulating agents. Incidence of barbiturate intoxication increased substantially following World War II and this paper details development of what became known as the ‘Scandinavian Method’ of treatment, which contributed substantially to the earliest establishment of intensive care units and to the practice and methods of intensive care medicine. Three names stand out for the pioneering of this treatment. Successively, psychiatrist, Aage Kirkegaard, for introducing effective anti-shock fluid therapy; anaesthetist, Eric Nilsson, for introducing anaesthesiologic principles, including manual intermittent positive pressure ventilation into management; and, psychiatrist, Carl Clemmesen, for introducing centralisation of seriously poisoned patients in a dedicated unit. Clemmesen's Intoxication Unit opened at the Bispebjerg Hospital, Copenhagen, on 1 October 1949. ICU pioneer Bjørn Ibsen suggested it was the initial ICU, while noting that it supplied Intensive Therapy for one type of disorder only (as had HCA Lassen's Blegdam Hospital unit for Denmark's 1952 to 1953 polio epidemic). Treatment for barbiturate poisoning during the 1950s in some other Scandinavian hospitals will also be considered briefly.
Dr Snow Killed a Bird: The Genesis of Pharmacokinetics and Pharmacodynamics in Anaesthesia
Authors: Mather L. E.
Published: January 2019

This essay presents a pharmacologist's perspective of what would be now called ‘preclinical research’ and ‘uncontrolled clinical trials’ surrounding the first public demonstration by William Thomas Green Morton of painless surgery achieved by the inhalation of ether in a patient at the Massachusetts General Hospital on 16 October 1846. Of the many people who made history in those earliest days of surgical anaesthesia in both the United States and Great Britain, John Snow stands out for his personal research that spanned basic science and clinical medicine. Primarily, Snow used the relationship between the vapour pressure of a volatile liquid and temperature to design a vaporiser. This allowed control of the inspired concentration of the volatile liquid epitomised by diethyl ether, and thus the time-course and depth of anaesthesia. In an era when developments in anaesthesia were almost exclusively based on empirical modifications to apparatus and technique, Snow, and to a lesser extent his contemporary Andrew Buchanan, stood out from all others in advancing the quantitative basis of anaesthesia. Both described the physiological basis of control over gas uptake whereby they related that gas moved across concentration gradients in the body: alveolar to arterial to tissue to venous gas tensions, and Snow devised a progressional semi-quantitative scale of five ‘stages’ of ether anaesthesia. They thereby introduced the elements of what would be referred to ‘pharmacokinetics’ and ‘pharmacodynamics’, a century later. This essay attempts to place them and their scientific insights into context with contemporaneous principal personae and knowledge.
Plasma Proteins and Dose Requirements of Tubocurarine
Authors: Shanks C. A. , Penny R.
Published: January 2019

Two groups, totalling 64 patients, were examined in an attempt to correlate the timed dosage of d-tubocurarine with plasma protein measurements. When dosage requirements were assessed on clinical grounds, three significant correlations emerged, but there were none when neuromuscular response was held at zero.

It is suggested that twitch response could be held at a steady level of depression to obtain a time-limited dose of relaxant, enabling dosage comparisons to be made with non-depolarisers.
A Dose-Response Study in Man of the Metabolism of Enflurane Used as a Supplement
Authors: Lowry C. J. , Sharp J. H. , Shumacher J. E. , Cousins M. J.
Published: January 2019

The metabolism of enflurane, used as a supplement to muscle relaxant and nitrous oxide anaesthesia, was studied in 19 healthy adult male surgical patients; seven control patients received halothane.

Patients receiving enflurane were randomly allocated to three groups:

Group I—1/2 MAC for 1/2 hour (dosage=1/4 MAC hour)

Group II—1/2 MAC for 2 hours (dosage=1 MAC hour)

Group III—1/2 MAC for 4 hours (dosage=2 MAC hours)

Metabolism of enflurane to inorganic fluoride (F-) was indicated by elevated serum F-concentration and elevated urinary excretion of F-. Peak serum F- concentration was measured in samples collected immediately at the end of enflurane anaesthesia and fell thereafter, approaching pre-operative levels at 48 hours; mean peak serum F- was 23·6± 4·2 μmol/l after 2 MAC hours of enflurane, 17·7±2·8 μmol/l after 1 MAC hour and 10·5± 0·9 μmol/l after 1/4 MAC hour. Nephrotoxic levels of serum F- (50 μmol/l) were not reached in any patient. Post anaesthetic renal function, including response to vasopressin, was normal in all groups. A dose-response relationship between enflurane dose and F- in serum and urine was established.
Drug Treatment of Malignant Hyperpyrexia
Authors: Austin K. L. , Denborough M. A.
Published: January 2019

Of the various drugs currently suggested for the treatment of malignant hyperpyrexia, dantrolene sodium was the most effective in reversing and inhibiting drug induced contractures in vitro, both in normal muscle and in muscle from patients who are susceptible to malignant hyperpyrexia. It is suggested that dantrolene sodium is the drug of choice for lowering the raised myoplasmic calcium concentrations in malignant hyperpyrexia.
Adsorption of Halothane from a Paediatric T-Piece Circuit by Activated Charcoal
Authors: Alexander K. D. , Stewart N. F. , Oppenheim R. C. , Brown T. C. K.
Published: January 2019

Experiments were conducted to compare the efficacy of six commonly available charcoals in adsorbing halothane in a paediatric T-piece system. Tests were also done to compare the effect of mass of charcoal and canister shape and size on adsorption and airways resistance. It was found that charcoals vary in their adsorptive capacity and that the size and shape of cannisters is important.
An Anaphylactoid Reaction to Gallamine Triethiodide
Authors: Evans Peter J. D. , McKinnon Ian
Published: January 2019

A patient suffered profound anaphylactoid reaction during anaesthesia. Intradermal skin testing confirmed the clinical impression that gallamine caused the reaction. The method of testing is discussed. Previous reports of hypersensitivity to the drug are reviewed, and the use of adrenaline, antihistamines and corticosteroids in patient management are considered.
Foetal Hypoxia—An Anaesthetist's approach to Classification and Prevention
Authors: Brownridge P.
Published: January 2019

Nearly one third of perinatal deaths are due to hypoxia occurring during pregnancy and labour. Many factors contribute to foetal hypoxia and in order to group these into orderly categories a classification of hypoxia, which is familiar to anaesthetists, has been applied to the maternal and foetal circulations. This theoretical approach forms a logical guide to our understanding the cause, prevention and treatment of foetal hypoxia.
Some Cardio-Pulmonary Effects of Infra-Renal Clamping of the Abdominal Aorta
Authors: Askitopolou H. , Young C. A. , Morgan M. , Sykes M. K.
Published: January 2019

No significant changes were found in heart rate, blood pressure, cardiac output, arterial blood gases or physiological deadspace: tidal volume ratio before and after clamping and unclamping the abdominal aorta below the renal vessels. Nevertheless, drugs should be available to reduce the afterload on the heart if any evidence of myocardial ischaemia appears during the period of aortic clamping. The importance of maintaining an adequate circulating blood volume at all times is stressed.
Case Report: Digital Ischaemia following Radial Artery Cannulation
Authors: Arthurs G. J.
Published: January 2019

A case of digital ischaemia following radial artery cannulation is described. The ischaemia developed following three hours hypotension seven days after the radial artery cannula had been removed. Patients with a thrombosed radial artery and a poor ulnar collateral circulation should be identified pre-operatively.
The Vestibulo-Ocular (Caloric) Reflex in the Diagnosis of Cerebral Death
Authors: Hicks R. G. , Torda T. A.
Published: January 2019

Correlation between vestibulo-ocular (caloric) reflex and the electroencephalogram was examined in 25 apparently brain-dead and 17 severely brain-injured patients. Among the apparently cerebrally dead, 3 patients still had some EEG activity and in 2, there was some response to caloric testing. In the control group of patients some EEG activity was present in all, and the caloric response was absent in 1. It is concluded that absence of caloric response has similar power to the electroencephalogram in confirming cerebral death. The diagnosis, however, must be made on the total information available, including history and examination of the patient. The policy of the Intensive Care Unit of Prince Henry Hospital in this regard is outlined.
An Anaesthetic Circuit to Improve Patient Monitoring by Gas Analysis
Authors: Salamonsen R. F. , Targett L. A. , Boyd T.
Published: January 2019

This circuit is designed to maximise the range of respiratory variables that can be monitored by a mass spectrometer either alone, or preferably in association with blood gas analysis. In particular, it permits monitoring of respiratory dead space, lung shunt, ventilation, and gas exchange, as well as inspired and end-expired gas concentrations. Laboratory and clinical data indicate satisfactory performance of the circuit both clinically and analytically. The circuit is most suitable for controlled ventilation where, by operating as a “minute volume divider”, it confers stability of minute volume on the manual ventilation technique.
Postinfusion Thrombophlebitis: Effect of Intravenous Drugs Used in Anaesthesia
Authors: Boon J. , Beemer G. H. , Bainbridge D. J. M. , Crankshaw D. P.
Published: January 2019

The method of sequential analysis was used to investigate the effect of injection of anaesthetic drugs into an intravenous infusion line on the incidence of thrombophlebitis in the 48 hours following surgery. Analysis of the results failed to show that anaesthetic drugs increased the incidence of thrombophlebitis (P=0.05), and further showed that they were not a causative factor (P=0.15).
Evaluation of Lyophilized Heparin Syringes for the Collection of Arterial Blood for Acid Base Analysis
Authors: Crockett A. J. , McIntyre E. , Ruffin R. , Alpers J. H.
Published: January 2019

The effects of liquid heparin on the analysis of acid/base status of arterial blood include a reduction in Pco2 and an increase in Po2. A study was performed to compare a lyophilised heparin syringe with a liquid heparin glass syringe for collection of blood for acid/base analysis. No significant difference between the variables measured in blood taken in the two syringes was demonstrated.
Calculating Clocks in Clinical Anaesthesia
Authors: Russell W. J. , Rowley M. P.
Published: January 2019

The modern electronic calculating clocks make possible a new approach to timing rates and events in clinical anaesthesia, particularly the accurate timing of short intervals such as respirator cycles and pulse rates. It also allows alarm reminders for set time intervals.
Transfer of Pethidine to CSF following Intravenous Administration
Authors: Mather Laurence E. , Pavlin Edward G.
Published: January 2019

To help delineate the contributions to analgesia evoked by central and spinal opiate receptors, pethidine was administered intravenously to dogs by bolus followed by infusion. Plasma and cerebrospinal fluid were sampled and assayed for pethidine. Cerebrospinal fluid concentrations followed a similar time course to plasma but with lower concentrations. The average cerebrospinal fluid:plasma ratio was 0.4 and resembled the fraction of unbound pethidine in plasma. It was concluded that cerebrospinal fluid concentrations after intravenous administration were so low that spinal action would be unlikely.
An Evaluation of Thermodilution Cardiac Output Measurement Using the Swan-Ganz Catheter
Authors: Runciman W. B. , Ilsley A. H. , Roberts J. G.
Published: January 2019

Errors in thermodilution cardiac output measurement were quantitated to determine the order of accuracy of routine measurements performed by unskilled personnel. In vitro and in vivo studies were undertaken to examine factors affecting the volume and temperature of the injectate, catheter thermistor and computer performance, effect of respiration, use of cold (0-4 °C) versus ambient temperature (20-25 °C) injectate, and the interpretation of measurements. Ambient temperature injectate incurred unacceptably large errors; cold injectate (injections were timed with respiration) produced variations in performance by equipment and personnel which accounted for only 2% of the variation between successive measurements. Real changes in cardiac output and inherent variability of the downslope of the thermal curve, necessitating an empirically based calculation, account for up to 10% variation between successive measurements. When cold injectate was used, and the average of three corrected measurements taken, thermodilution cardiac output measurements were within 10% of a simultaneous dye dilution measurement.
The Epidemiology and Clinical Features of Anaphylactic Reactions in Anaesthesia
Authors: Fisher M. McD. , More D. G.
Published: January 2019

Severe anaphylactoid reactions during anaesthesia in 116 patients are described. The majority of patients who reacted to induction agents had previous exposure to the drug, while the majority of patients who reacted to muscle relaxants had not.

There was a statistically significant increased incidence of allergy, atopy, asthma and previous reactions in patients who had reactions compared with a control group undergoing uneventful anaesthesia. There was no correlation between abnormalities in immunoglobulins or resting complement levels and a history of allergy or atopy.

Antihistamines, steroids and bronchodilators alone did not prevent reactions and three patients reacted to test doses with Althesin. Reactions usually occurred during induction of anaesthesia, but may occur at any time in the perioperative period.

No one drug produced reactions that differed in severity or clinical features from any other drug.

Clinical features included skin changes, oedema, cardiovascular collapse, bronchospasm, gastrointestinal symptoms, prolonged unconsciousness, convulsions and pulmonary oedema. Four patients died.
Postoperative Vomiting in Children
Authors: Rowley M. P. , Brown T. C. K.
Published: January 2019

A survey of the frequency of postoperative vomiting in children was conducted over a two-month period. Completed questionnaires were obtained for 1183 patients. The important findings were a lower incidence of vomiting in children under three years of age and a significantly increased incidence of vomiting in patients premedicated with paparveretum and hyoscine.

This clinical review highlighted areas where improvements could be made, particularly in the management of patients who vomit frequently. It also provides information which can be used for setting up more detailed controlled studies.
Fresh Autologous Blood Transfusion and Platelet Counts after Cardiopulmonary Bypass Surgery
Authors: Iyer V. S. , Russell W. J.
Published: January 2019

The effect of fresh autologous blood transfusion on platelet count and blood requirement in the early postoperative period is examined in a control group and in patients receiving early and late autologous replacement. Withdrawal of blood in the autologous groups appeared to enhance platelet numbers as the autologous groups had higher mean platelet counts than the control group immediately after bypass, in spite of having lower mean haematocrit. After bypass all groups showed a progressive rise in platelet count with time. A substantial part of the rise was explained by haemoconcentration resulting from fluid shifts but there was also an increase in the total circulating platelet numbers. There was no difference in postoperative blood loss between the three groups. Autologous blood replacement hastens the postoperative rise in platelet count but does not alter the postoperative blood loss.
The Effects of Lignocaine Spray on the Laryngeal Mucosa of the Cat
Authors: Rex M. A. E. , Sutton R. H. , Reilly J. S.
Published: January 2019

The laryngeal mucosa of cats which had been treated with a lignocaine aerosol spray prior to endotracheal intubation was examined histologically. A degree of oedema and cell damage was apparent. When one side of the larynx was sprayed before intubation and the other side protected in the same cat, cellular damage was greater on the side which received the lignocaine spray. In no cat were the changes considered severe enough to constitute a post-anaesthetic hazard.
Blood Flow, Sympathetic Activity and Pain Relief following Lumbar Sympathetic Blockade or Surgical Sympathectomy
Authors: Walsh John A. , Glynn Christopher J. , Cousins Michael J. , Basedow Robert W.
Published: January 2019

The physiological effects of local anaesthetic (bupivacaine), neurolytic (phenol) blockade and surgical ablation of the lumbar sympathetic chain were assessed in patients with peripheral vascular disease or sympathetic dystrophy. Local anaesthetic blockade in 49 patients resulted in significant decrease in pain, plantar sweating and in the vasoconstrictor ice response of the foot, as well as a significant increase in skin temperature and foot blood flow. Subsequent neurolytic blockade in 31 of these patients achieved an effective denervation as assessed by the same physiological measurements. The magnitude of changes in blood flow and sympathetic activity were similar for local anaesthetic and neurolytic blockade as well as in six patients who underwent surgical sympathectomy.
Ranitidine Prophylaxis before Anaesthesia in Early Pregnancy
Authors: Duffy B. L. , Woodhouse P. C. , Schramm M. D. , Scanlan C. M.
Published: January 2019

Forty patients presenting for vaginal termination of pregnancy, divided randomly into four groups, received either no medication, sodium citrate 30 ml orally, ranitidine 150 mg orally or ranitidine 50 mg intravenously. During the procedure, gastric contents were removed by orogastric tube for volume and pH measurements. Ranitidine, orally and intravenously, significantly increased gastric pH and reduced gastric volume. In the control group only one pH was greater than 2.5. Sodium citrate raised the pH above 2.5 in 6 out of 10 patients. Fasting patients in the first months of pregnancy may be at risk of developing Mendelson's syndrome. Ranitidine is very effective in increasing gastric pH and at the same time reducing gastric volume in such patients.
The Combibag: An Evaluation of a New Self-Inflating Resuscitator
Authors: Cramond T. , O'Callaghan J. P.
Published: January 2019

The Combibag self-inflating resuscitator incorporates an adult and a paediatric segment as well as a two-stage pressure limiting safety valve. The resuscitator is not without problems. A sizeable forward leak of gas can occur beyond the patient valve. The patient valve design is such that a spontaneously breathing patient draws his inspired gas entirely from room air. Problems can also occur with the valve either sticking or being blown forward off its seating, thereby making the resuscitator inoperable and dangerous. The use of a two-stage pressure-limiting safety valve should prevent unnecessary barotrauma but could well lead to unrecognised venting with inadequate ventilation when used by inexperienced personnel.
Surgery without Pain — Part 1: Background
Authors: Smith W. D. A.
Published: January 2019

This paper was commissioned to cover the beginnings of anaesthesia: the transition from surgical operations with pain to those without. It reviews some previous pre-anaesthetic histories (Part I): it focuses upon attitudes to pain; and it seeks evidence from the one hundred years before the discovery of anaesthesia. Finally (Part II) it outlines the introduction of nitrous oxide and of ether anaesthesia.
Newer Modes of Mechanical Ventilatory Support
Authors: Cameron P. D. , Oh T. E.
Published: January 2019

Recent modes of ventilatory support aim to facilitate weaning and minimise the physiological disadvantages of intermittent positive pressure ventilation (IPPV). Intermittent mandatory ventilation (IMV) allows the patient to breathe spontaneously in between ventilator breaths. Mandatory minute volume ventilation (MMV) ensures that the patient always receives a preset minute volume, made up of both spontaneous and ventilator breaths. Pressure supported (assisted) respiration is augmentation of a spontaneous breath up to a preset pressure level, and is different from ‘triggering’, which is a patient-initiated ventilator breath. Other modes or refinements of IPPV include high frequency ventilation, expiratory retard, differential lung ventilation, inversed ratio ventilation, ‘sighs’, varied inspiratory flow waveforms and extracorporeal membrane oxygenation. While these techniques have useful applications in selective situations, IPPV remains the mainstay of managing respiratory failure for most patients.
Opioid Pharmacokinetics in Relation to their Effects
Authors: Mather L. E.
Published: January 2019

The chemical structure of drug molecules determines their fundamental pharmacological properties by ‘fit’ to the receptor, but the physicochemical properties, particularly lipid solubility and fraction un-ionised, dominate in determining distribution in the body and the rate of access to the biophase containing the drug receptors. For example, fentanyl appears much more potent than morphine because similar effective biophase concentrations are achieved with much smaller doses. Pharmacokinetic and pharmacodynamic investigations of the relationships between dose and the time-courses of blood concentrations and pharmacological effects of opioid drugs have helped explain the commonly observed variability between patients and have been useful in deriving effective dosage regimens of opioids such as pethidine, morphine, fentanyl and methadone where blood concentrations are a determinant of pharmacological response and ‘target’ analgetic blood opioid concentrations have been identifiable. However, there are instances when blood opioid concentrations are not determinants of the analgetic response. Examples include opioids, such as buprenorphine, for which the drug-receptor dissociation rate determines the duration of action, heroin which first has to be metabolised to become an agonist, pentazocine which is an agonist at some opioid receptors and an antagonist at others, and opioids placed intra-spinally acting on receptors in the spinal cord.
Opiate Anaesthesia
Authors: Stanley T. H.
Published: January 2019

Current use of opioids in anaesthesia is reviewed with particular emphasis on the use of opioids in anaesthetic doses, techniques that recently have become popular in cardiovascular anaesthesia. A major benefit of opioid anaesthesia (particularly fentanyl) is the cardiovascular stability which obtains during induction and throughout operation, even in patients with severely impaired cardiac function. Anaesthetic doses of morphine are associated with a higher incidence of cardiovascular disturbances and other problems. Pethidine is unsuitable for cardiovascular surgery because of severe haemodynamic disturbances when high doses are given. Sufentanil and alfentanil may prove more suitable alternatives.

High doses of opioids can reduce or prevent hormonal and metabolic responses to the stress of surgery. Even very large doses of fentanyl or its new analogues do not prevent marked increases in plasma catecholamine concentrations in response to cardiopulmonary bypass. The reduction in hormonal and metabolic stress response does not appear to continue postoperatively.
A Prospective Study of Dextran-induced Anaphylactoid Reactions in 5745 Patients
Authors: Paull J.
Published: January 2019

A prospective study of dextran-induced anaphylactoid reactions (DIAR) in 5745 gynaecological and obstetric patients who received dextran 70 solution intravenously while undergoing major surgery revealed 8 patients who had Grade I or II reactions and 7 patients who had Grade III or IV reactions. The incidence of severe reactions was 1:821 patients treated. The overall incidence of reactions per patient treated was 1:383. One neonatal death followed a dextran-induced cardiac arrest in a woman about to undergo caesarean section. The risks of dextran 70 treatment exceeded the risks of thromboembolism in these patients.
The Effect of Ro15-1788 (Anexate) on Conscious Sedation Produced with Midazolam
Authors: Rodrigo M. R. C. , Rosenquist J. B.
Published: January 2019

A double-blind cross-over randomised study was performed to investigate whether Ro15-1788 (Anexate) adequately reversed the conscious sedation with midazolam so that patients were clinically recovered and fit for discharge quicker than when midazolam was used alone. Twenty-eight healthy patients between 18 and 34 years sedated with midazolam for bilateral 3rd molar surgery, one side being operated on at each visit. Ro15-1788 or normal saline (placebo) was given at the end of the surgical procedure at the first visit and the alternative at the second visit. Recovery with Ro15-1788 was significantly quicker than with the placebo, both by subjective (86%) and objective (93%) evaluation. Patients’ evaluation indicated that only 61% were more alert at home with Ro15-1788. Postoperative adverse effects were similar in both groups.
An Evaluation of Intravenous Infusion Pumps and Controllers
Authors: Runciman W. B. , Ilsley A. H. , Rutten A. J. , Baker D. , Fronsko R. R. L.
Published: January 2019

The accuracy, safety, reliability and cost of use of 35 intravenous infusion pumps and 3 flow controllers were assessed. When infusing saline 11 out of 17 syringe pumps, 3 out of 5 peristaltic pumps, 1 out of 2 roller pumps and all 14 cassette pumps tested were accurate to within 5% over their full ranges of operation. There was no significant change in the performance of any of the pumps tested when saline was infused through a standard resistance, except in the cases of the 3 flow controllers which were unable to infuse at all against the resistance. When 50% dextrose was infused, delivery by two peristaltic pumps was reduced by 23 and 38%. No pump cut out or alarmed at pressures of up to 200 mmHg and 21 pumps continued to infuse against pressures of 750 mmHg or greater. Surges of up to 0.5 ml occurred after release of an outlet obstruction. One device was fitted with a variable high pressure alarm. This device could also measure pressure in the infused vessel and was found to be accurate for measurements of central venous pressure. The cost of consumables for a single use for syringe pumps ranges from A$2 to $5, for peristaltic and roller pumps from A$1 to $10, and for cassette pumps from A$7 to $12, with an additional A$2 for a burette. Accurate delivery of intravenous fluids and drugs is available but is expensive and requires the operator to be specially trained. No simple, cheap, accurate device is yet available.
Combined Morphine-Bupivacaine Caudals for Reconstructive Penile Surgery in Children: Systemic Absorption of Morphine and Postoperative Analgesia
Authors: Wolf A. R. , Hughes D. , Hobbs A. J. , Prys-Roberts C.
Published: January 2019

We wished to determine if the addition of a small dose of morphine (0.05 mg.kg−1) to a caudal solution of 0.25% bupivacaine could extend the duration of analgesia after major reconstructive penile surgery and also to measure the systemic absorption of morphine after caudal injection. Thirty children undergoing reconstructive penile surgery received a caudal injection of 0.25% bupivacaine 0.75 ml.kg−1 with or without morphine 0.05 mg.kg−1. All patients awoke pain-free, but eight of the fifteen patients receiving bupivacaine alone required supplementary injections of opioid postoperatively, whereas none of the patients receiving the bupivacaine-morphine mixture required additional opioids. The incidence of side-effects was similar for the two groups.

Morphine was absorbed rapidly after caudal injection to reach a peak plasma level of 21.2 (±4.8) ng.ml−1 at ten minutes and then fell to 10.1 (±3.8) ng.ml−1 at one hour and 4.1 (±2.6) ng.mh−1 at three hours. These levels are low compared with plasma levels associated with systemic analgesia. We conclude that the extended duration of analgesia from morphine 0.05 mg/kg given caudally is due at least in part to specific spinal analgesia.
Epidural Fentanyl Effect on Cardiac Output and Hepatic Blood Flow
Authors: Beavis R. E. , Crotty B. , Osborne A. , Hochmann M.
Published: January 2019

Epidural opioids provide high quality analgesia with no clinically apparent effect on the circulation or on specific organ blood flow. Little investigative data is available to support these impressions of circulatory stability. Ten patients presenting for thoracotomy were studied at rest preoperatively to determine if epidural fentanyl had any effect on the systemic circulation or hepatic blood flow. Intravascular pressure measurements, cardiac output estimation using the dye-dilution technique and estimation of altered hepatic blood flow by measuring the clearance of indocyanine green were performed. No significant changes in heart rate, perfusion pressure, cardiac output or hepatic blood flow were detected following the administration of fentanyl 50 μg into the epidural space.
Comparative Evaluation of Propofol or Methohexitone as the Sole Anaesthetic Agent for Microlaryngeal Surgery
Authors: Best N. , Traugott F.
Published: January 2019

Propofol or methohexitone was given to the same twenty patients on two separate occasions during total intravenous anaesthesia for microlaryngeal surgery. With propofol the quality of induction was superior. Fewer patients required supplementation. Heart rate and blood pressure were well controlled at levels of 110–120% baseline. There were fewer side-effects during maintenance and recovery. Patients were able to return home earlier. However, apnoea and pain on injection occurred frequently, the latter when injection was made into the dorsum of the hand. With methohexitone, apnoea, abnormal movement, nausea, vomiting, headache, restlessness and confusion were common. Cardiovascular variables were poorly maintained at levels of 170–180% baseline. The results suggest that propofol is suitable as the sole anaesthetic agent in patients undergoing microlaryngeal surgery.
Lean Tissue Mass is a useful Predictor of Induction dose Requirements for Propofol
Authors: Leslie K. , Crankshaw D. P.
Published: January 2019

The effect of age and sex on ED50 values for propofol was studied in 92 patients aged between 16 and 85 years. All doses were based on lean tissue mass (LTM). The end-point for loss of consciousness was loss of the ability to hold a light object. The mean of the ED50 values for males was 1.31 mg.kg LTM−1 and for females 1.28 mg.kg LTM−1. For males the ED50 values ranged from 0.94 to 1.69 mg.kg LTM−1. For females, the range was 1.06–1.57 mg.kg LTM−1. On statistical analysis, these differences were not significant. These data contrast with other studies in which dosage was based on total body mass where a decrease in dose requirement with age was demonstrated. We propose that by using lean tissue mass to calculate dosage, considerable normalisation of patient response can be achieved. There is considerable inter-individual variation in response to propofol. Age is less important than this variation in determining the correct dose for each patient, provided doses are based on LTM.
Anaesthesia System Errors
Authors: Galletly D. C. , Mushet N. N.
Published: January 2019

A simple schema of anaesthesia system error evolution is described. This was used, with a modified critical incident technique, as a framework for data gathering and error analysis. The outline places emphasis on recovery pathways and, in addition to causal and contributory factors, was able to identify many factors which aided or hindered the processes of error detection, diagnosis and management. On average, 8.1 factors were identified which were considered to have significantly influenced the genesis and evolution of each reported error. Differences were apparent in the type of factors which determined error production and aspects of the recovery sequence. The described schema is suggested to be of value for data generation, and as a tool for discussion as part of anaesthesia quality assurance.
A Method of Spontaneously Breathing Anaesthesia in the Prone Position without Endotracheal Intubation
Authors: Schebesta A. G. N. , Wong T. A. W.
Published: January 2019

A method of delivering anaesthetics to spontaneously breathing patients in the prone position was developed. The arterial blood gases of eighteen patients undergoing short-stay surgery and using this technique were analysed. The results showed the influence of premedication on arterial pH and PCO2 levels but they do not differ from accepted values for similar anaesthesia on supine patients. The advantages and disadvantages of this technique are discussed.
The Effect of the Depth of Neuromuscular Blockade on the Haemodynamic Response to Tracheal Intubation
Authors: Gibbs N. M. , Harrison B. A.
Published: January 2019

The effect of two different doses of vecuronium on the heart rate and mean arterial pressure response to tracheal intubation was compared in 32 adult ASA class I patients. It was found that the higher dose of vecuronium (2.5 × ED95) produced greater depression of the evoked electromyogram (P < 0.01), and provided better intubating conditions (P < 0.01) than the lower dose of vecuronium (1 × ED95). However, the heart rate and the mean arterial pressure response to tracheal intubation was similar with both doses. The results indicate that, within the range of neuromuscular blockade commonly used to facilitate tracheal intubation, the depth of neuromuscular blockade per se does not affect the haemodynamic response to intubation.
Does Combined Epidural Lignocaine and Fentanyl Provide Better Anaesthesia for ESWL than Lignocaine Alone?
Authors: Cook R. J. , Neerhut R. , Thomas D. G.
Published: January 2019

The efficacy of epidural fentanyl combined with lignocaine 1.5% with adrenaline 1:200,000 was studied in a randomised, double-blind, controlled trial of two hundred patients undergoing extracorporeal shock wave lithotripsy with or without ancillary procedures. The quality of anaesthesia was assessed using linear analogue pain scores, the patient's impression, and the rate of intra-operative intervention by the anaesthetist. Postoperative symptomatology was also recorded. The only significant difference lay postoperatively in that the fentanyl-ancillary procedure sub-group had less pain approximately one hour postoperatively (P = 0.01).

In the context of this study and in the presence of an adequate autonomic and somatic local anaesthetic blockade, the addition of epidural fentanyl does not appear to confer any significant advantage other than to enhance postoperative analgesia.
Patient-controlled Analgesia: Can it be Made Safer?
Authors: Kluger M. T. , Owen H.
Published: January 2019

Patient-controlled analgesia (PCA) has been shown to provide superior pain relief when compared with standard therapy options for postoperative analgesia. If PCA is to be implemented widely in teaching, private and country hospitals, its effectiveness needs balanced with a high safety profile. This can be achieved by consideration of patient selection, comprehensive education of patients, medical and nursing staff and equipment familiarisation. Continuous clinical audit allows identification of problem areas along with monitoring analgesic efficacy.
Data Recording and Trend Display during Anaesthesia using ‘MacLab’
Authors: Kennedy R. R.
Published: January 2019

A single screen display of variables monitored during anaesthesia may be economically superior to the ‘stack’ of monitors seen in many anaesthetising locations. A system based on a MacLab (Analogue Digital Instruments) analogue-to-digital convertor used in conjunction with a Macintosh computer was evaluated. The system was configured to provide trend displays of up to eight variables on a single screen. It was found to be a useful adjunct to monitoring during anaesthesia. Advantages of this system are low cost, flexibility, and the quality of the software and support provided. Limitations of this and other similar systems are discussed.
The Effect of Anaesthetic Agents on Platelet Function
Authors: Gibbs N. M.
Published: January 2019

This paper reviews studies which have investigated the effect of anaesthetic agents on platelet function The results of these studies suggest that halothane is the only agent in current use which inhibits platelet function in concentrations used clinically. Nitrous oxide appears to cause only a modest inhibition, while enflurane and isoflurane appear to have minimal or negligible effects. There is no current evidence that intravenous induction agents opiates, or muscle relaxants affect platelet function. Reports indicate that local anaesthetic agents inhibit platelet aggregation, but only at concentrations far greater than peak plasma concentrations found during clinical use. Epidural anaesthesia may be associated with a reduction in platelet aggregation through a mechanism unrelated to direct local anaesthetic inhibition. The clinical significance of the effect of halothane on platelet function is not known. However, it is possible that halothane may affect bleeding or thrombotic complications in a similar manner to other ‘anti-platelet’ drugs.
Gastric Emptying in the Postpartum Period
Authors: Gin T. , Cho A. M. W. , Lew J. K. L. , Lau G. S. N. , Yuen P. M. , Critchley J. A. J. H. , Oh T. E.
Published: January 2019

We measured gastric emptying, using the technique of paracetamol absorption, in eight women on their first and third postpartum day. Gastric emptying was rapid and there was no difference between the first and third day in the time to peak plasma concentration of paracetamol. Six women returned after six weeks for a further study. Gastric emptying was still rapid but the metabolism of paracetamol appeared to be slower than that found during the immediate postpartum period. These findings suggest that fluid fasting guidelines in patients more than one day postpartum need not be different from those in non-pregnant patients.
Use of Warm Local Anaesthetic Solution for Caudal Blocks
Authors: Lim E. T. M. , Chong K. Y. , Singh B. , Jong W.
Published: January 2019

A double-blind study was undertaken to investigate the effect of prewarmed local anaesthetic solution on the latency of onset of caudal blocks. Forty-four (ASA I-II) patients were allocated into two equal groups. In Group A, the local anaesthetic solutions were injected at room temperature (25°C), while in Group B, they were injected at 37°C. All the caudal blocks were performed using 20 ml of lignocaine 1.5% with adrenaline 1:200,000. The speed of onset of perianal analgesia was found to be significantly faster (39%) with the prewarmed local anaesthetic solution (P < 0.05). No adverse effects were observed.
Fibreoptic Bronchoscopy in the Critically Ill: A Prospective Study of its Diagnostic and Therapeutic Value
Authors: Bellomo R. , Tai E. , Parkin G.
Published: January 2019

Aim

A prospective study was undertaken to assess the diagnostic value and therapeutic usefulness of fibreoptic bronchoscopy in the critically ill.

Method

Fifty-six bronchoscopies were performed in fifty patients. Biochemical, radiological, microbiological and clinical assessments were made before and after each procedure.

Results

Eighteen fibreoptic bronchoscopies were performed for therapeutic indications (32.1%) of which ten (55.6%) yielded a useful outcome. Thirty-eight bronchoscopies were for diagnostic purposes (67.8%) of which 22 (5 7.9%) were clinically useful. Broncho-alveolar lavage was performed in twenty-eight cases (50%) and it led to a clinically useful diagnosis in 17 (60.7%). There was no major complication. A subgroup of patients was defined (persistent left lower lobe collapse or consolidation following thoracic or abdominal surgery) in whom fibreoptic bronchoscopy usually did not yield a useful outcome.

Conclusion

The use of fibreoptic bronchoscopy in the Intensive Care Unit, in combination with the technique of broncho-alveolar lavage, results in a clinically useful outcome in the majority of cases. Fibreoptic bronchoscopy is an effective and safe diagnostic and therapeutic tool in critically ill patients.