Anaesthesia and Intensive Care

The performance of a hollow fibre artificial lung ('Capiox E') was analysed by measurement of the 'parallel deadspace' of the device under varying conditions in 21 patients. The efficiency with which carbon dioxide was exchanged was determined by the time available for equilibration between the blood and gas phases. When this equilibration coefficient was less than 12 seconds per litre of blood flow per litre of gas flow, there was a marked reduction in the efficiency of gas exchange. Under certain conditions, the 'counter-current' design of the device apparently permitted the clearance of carbon dioxide at a partial pressure greater than that which was found in the mixed venous blood. This anomalous behaviour may represent in vivo confirmation of the Haldane effect.

Major non-cardiac surgery is associated with postoperative morbidity, and perioperative central venous oxygen saturation (ScvO2) may be a predictor of morbidity. This pilot study aimed to define intraoperative ScvO2 and to identify factors associated with postoperative complications. ScvO2 (reflection spectrophotometry) was recorded continuously in a convenience sample of adults undergoing high-risk general surgery. Demographics, intraoperative management, surgery duration, postoperative complications and deaths within 28 days were recorded. Data from 51 patients were analysed. Two (4%) died and 24 (47%) had at least one complication (range 1 to 5). The hospital length-of-stay and duration of surgery were longer in those with complications (22.1±6.1 versus 9.6±3.6 days, P >0.0001, and 328±162 minutes versus 241±94 minutes, P=0.02, respectively). Overall, the ScvO2 was 82±8% and ranged from 40% to 97% with 17 (33%) patients having at least one episode of ScvO2 >70%. Hospital le...

This review discusses the issues to be considered in establishing new or extending existing high dependency unit (HDU) services. A defined high dependency service becomes cost-effective when patient care requires more than one nurse for three patients. Professional guidelines for HDUs vary and there are no national accreditation criteria. Casemix and service delivery specifications for the HDU need to be defined and agreed upon within the institution. Establishing a new HDU service requires changes to care delivery. Many potential HDU patients are currently managed in general wards or in the intensive care unit. The service should be discussed widely and marketed within the institution, and the development of defined working relationships with the ICU and primary care teams on the wards is mandatory.

Current methods of crystalloid preload administration prior to spinal anaesthesia for elective caesarean section are relatively ineffective in preventing hypotension. This study examined the relevance of the timing of the fluid administered. Fifty women were randomly allocated to receive either 20 ml x kg(-1) of crystalloid solution during 20 minutes prior to induction of spinal anaesthesia (preload), or an equivalent volume by rapid infusion immediately after induction (coload). Significantly more patients in the coload group did not require vasopressor therapy pre-delivery (P=0.047). The coload group required a lower median dose (P=0.03) and a lower median number (P=0.04) of ephedrine doses for the treatment of maternal hypotension pre-delivery. There was no between-group difference in either the total cumulative dose, or in the total number of doses of ephedrine. Neonatal outcomes among the two groups were similar. Rapid crystalloid administration after, rather than over 20 minut...

Gastric emptying should be considered by anaesthetists not only because of the risk of pulmonary aspiration, but also to determine the systemic availability of substances given orally. Delayed gastric emptying prevents a return to oral feeding, increases nausea and vomiting and may result in morbidity and mortality! The importance of these considerations has increased with recent emphasis on day surgery and shorter admissions. Several papers and editorials have recently reexamined the guidelines for preanaesthetic food and fluid restrictions. 2 • 3 This review describes the physiology of gastric emptying, the methods currently in use for its measurement and the limitations of each method. This information may explain many of the apparent contradictions in published data on gastric emptying in the perianaesthetic period. Factors such as disease states and pharmacological effects which may influence gastric emptying are summarised. Unfortunately, few measurements of gastric emptying have actually been made in patients during the perianaesthetic period, so that data must be extrapolated from studies of healthy volunteers, non-surgical patients or from animal studies. In addition these results may not apply to all types of gastric contents as liquids, digestible solids and indigestible solids empty with different rates and patterns, due to the functional anatomy of the stomach.' Both neural and humoral influences on gastric emptying must be considered. The extrinsic innervation of the stomach is via the vagus and sympathetic nerves, and both contain afferent and efferent fibres. 5 The stomach wall also has an extensive intrinsic nervous system, the most important component being the 'M.D., Consultant Anaesthetist tEA.N.Z.C.A.

Veterinary care has continued to advance by implementing more of the equipment and techniques that are commonly used in human medicine. This includes the placement of arterial catheters and pulmonary artery catheters and continuous monitoring of arterial pressure, central venous pressure, and pulmonary artery pressure. This article describes the technique for placement of appropriate catheters, the equipment that is needed, and the waveforms that are obtained when measuring direct arterial pressures, central venous pressures, and pulmonary arterial pressures. Copyright 0 2000 by W.B. Saunders Company M onitoring of the cardiovascular system is essential when caring for critical patients. Methods to monitor the cardiovascular system include electrocardiogram (ECG) and measurement of arterial blood pressure, central venous pressure (CVP), pulmonary artery pressure (PAP), and pulmonary artery occlusion pressure (PAOP). The use of an ECG and indirect measurement of blood pressure has become relatively common in veterinary medicine, whereas direct arterial blood pressure (DABP) measurement and CVP monitoring are not widely performed. Direct arterial pressure monitoring is much more accurate than noninvasive methods in both awake and anesthetized veterinary patients, especially critically ill patients, and allows for continuous measurements instead of intermittent values that are obtained with noninvasive meth-From the

Robotic surgery is gaining widespread popularity due to advantages such as reduced blood loss, reduced postoperative pain, shorter hospital stay and better visualisation of fine structures. Robots are being used in urological, cardiac, thoracic, orthopaedic, gynaecological and general surgery. Robotic surgery received US Food and Drug Administration approval for use in gynaecological surgery in 2005. The various gynaecological robotic operations being performed are myomectomy, total and supracervical hysterectomy, ovarian cystectomy, sacral colpopexy, tubal reanastomosis, lymph node dissection, surgery of retroperitoneal ectopic pregnancy, Moskowitz procedure and endometriosis surgery. The anaesthetic considerations include difficult access to the patient intraoperatively, steep Trendelenburg position, long surgical duration and the impact of pneumoperitoneum. We highlight the complications encountered in these surgeries and methods to prevent these complications. Robotic gynaecolog...

A double-blind study consisting of 339 randomly selected children investigated the effects of several premedicants on the preoperative and postoperative behaviour of children who underwent day-stay surgery. Patients were allocated into two groups. Group 1 consisted of 165 children aged between 6 and 47 months. Group 2 consisted of 174 children aged four years and older to a body weight of 50 kg. Each child received one premedicant. Both groups included alprazolam 0.005 mg/kg, midazolam 0.3 mg/kg and placebo. In addition Group 1 included chloral hydrate 40 mg/kg and Group 2 diazepam 0.25 mg/kg. Chloral hydrate produced superior conditions (more patients calm or asleep) at induction of anaesthesia. Postoperative behaviour and incidence of vomiting were similar for all drugs. No premedicant reduced anxiety in the older group. The time to awaken postoperatively with diazepam was longer than with placebo. Alprazolam and midazolam were unpalatable for children over four years and conferre...

The haematological effects of Brown Snake (Pseudonaja) species (textilis, affinis, nuchalis) were studied in anaesthetised, mechanically ventilated dogs. Marked thrombocytopenia, depletion of serum fibrinogen and prolonged prothrombin and activated partial thromboplastin time, were recorded at 5 to 10 and 30 to 40 minutes after intravenous envenomation. Fibrin degradation products were not elevated. Because these haematological effects occurred simultaneously with cardiovascular depression (previously reported), we postulate that hypotension sometimes observed in human envenomation may be due to intravascular coagulation with myocardial ischaemia.

A prospective analysis of 100 successive intubations with Robertshaw tubes in patients submitted for routine thoracic surgery is presented. Clinical guidelines for intubation were used as the protocol. Tube position was judged on clinical assessment only and not ...

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.

We wanted to provide training in the use of drawover techniques and apparatus at an Australian teaching hospital. Equipment based on the Diamedica vaporiser was selected as it is suitable for use with sevoflurane. A lack of standards specific to drawover equipment from either anaesthetic professional bodies or national standards authorities hinders introduction of such equipment to Australian hospitals. Two systems were purchased, the Diamedica Portable Anaesthesia System and a Glostavent anaesthetic machine. Changes made to the equipment to increase its safety and to comply with Australian standards are described.

In sickle cell disease, cardiopulmonary bypass may induce red cell sickling. Partial exchange transfusion reduces the circulating haemoglobin S level. We report the management of a child with sickle cell disease who required surgical closure of a ventricular septal defect. Preoperative exchange transfusion of 50% of the total blood volume was performed with fresh packed red cells over three days. Further exchange transfusion was performed as cardiopulmonary bypass commenced. The haemoglobin S level was reduced from 76% to 37%. The blood removed from the patient during the exchanges was processed allowing storage and re-infusion of the patient's plasma and platelets. Combined preoperative and intraoperative exchange transfusions, instead of a single stage 50% volume exchange, was effective and potentially avoids larger haemodynamic effects. Cardiopulmonary bypass was conducted at normothermia and cold cardioplegia was avoided (fibrillatory arrest was used during the surgical repa...

Current status of opiate receptors and their agonists is reviewed--basic aspects of receptor theory, the importance of stereospecificity in drug-receptor interactions and the role of 'second messengers' in drug action. The three classes of endogenous opioids, originating from three distinct genes, are discussed: pro-opiomelanocortin, giving rise to beta-endorphin, ACTH and various MSHs; pro-enkephalin, giving methionine enkephalin and leucine enkephalin; and prodynorphin; their anatomical distribution and the main classes of receptors with which they interact, the mu-receptor, with a high affinity for met-enkephalin and beta-endorphin (as well as morphine and dynorphin A); the delta-receptor for which the primary ligand is leu-enkephalin; and the kappa-receptor which is the main target for the dynorphins. Functional roles for endogenous opioids are considered. Essentially they are inhibitory to target neurones, depressing motor reflexes, baroreflexes and nociception. They al...

When evaluating assessments, the impact on learning is often overlooked. Approaches to learning can be deep, surface and strategic. To provide insights into exam quality, we investigated the learning approaches taken by trainees preparing for the Australian and New Zealand College of Anaesthetists (ANZCA) Final Exam. The revised two-factor Study Process Questionnaire (R-SPQ-2F) was modified and validated for this context and was administered to ANZCA advanced trainees. Additional questions were asked about perceived value for anaesthetic practice, study time and approaches to learning for each exam component. Overall, 236 of 690 trainees responded (34%). Responses indicated both deep and surface approaches to learning with a clear preponderance of deep approaches. The anaesthetic viva was valued most highly and the multiple choice question component the least. Despite this, respondents spent the most time studying for the multiple choice questions. The traditionally low short answer...

Processed electroencephalography is used in adults to guide anaesthesia, but the algorithms used may not apply to infants. Knowledge of infants' electroencephalogram (EEG) responses to anaesthetics is fragmentary. An earlier pilot study suggested amplitude-integrated EEG (aEEG) may be a useful measure of anaesthetic effect. The aim of this study was to determine how aEEG changes between awake and anaesthetised children of varying ages and to compare the response to that seen with Spectral Edge Frequency 90% (SEF90). A prospective observational study of children receiving a general anaesthetic was conducted. Anaesthetic regimen remained at the discretion of the treating anaesthetist. EEG data were collected using the BrainZ ReBrim(TM) monitor using forehead and biparietal montages. SEF90 and aEEG were compared across age groups, EEG montage and between awake and anaesthetised states. A total of 178 children (aged 24 days to 14 years) were recruited. All aEEGs were greater during ...

This study aimed to assess the effects of sugammadex and neostigmine/atropine on postoperative cognitive dysfunction (POCD) in adult patients after elective surgery. A randomised, double-blind controlled trial was carried out on 160 American Society of Anesthesiologists physical status I to III patients who were >40 years of age. The Mini-Mental State Evaluation, clock-drawing test and the Isaacs Set test were used to assess cognitive function at three timepoints: 1) preoperatively, 2) one hour postoperatively, and 3) at discharge. The anaesthetic protocol was the same for all patients, except for the neuromuscular block reversal, which was administered by random allocation using either sugammadex or neostigmine/ atropine after the reappearance of T2 in the train-of-four sequence. POCD was defined as a decline ≥1 standard deviation in ≥2 cognitive tests. The incidence of POCD was similar in both groups at one hour postoperatively and at discharge (28% and 10%, in the neostigmine group, 23% and 5.4% in the sugammadex group, P=0.55 and 0.27 respectively). In relation to individual tests, a significant decline of clock-drawing test in the neostigmine group was observed at one hour postoperatively and at discharge. For the Isaacs Set test, a greater decline was found in the sugammadex group. These findings suggest that there are no clinically important differences in the incidence of POCD after neostigmine or sugammadex administration.

Psychiatric aspects of drug overdose in adult suicide and suicide attempts are reviewed. Particular reference is given to studies reported from Australia. The findings of a recent study from the Royal Melbourne Hospital with regard to age-sex distribution, drugs ~tsed in self-poisonings, clinical state of the patient on admission and psychiatric diagnosis are presented and discussed.

The intensive care unit (ICU) is one of the most technically advanced environments in healthcare, using a multitude of medical devices for drug administration, mechanical ventilation and patient monitoring. However, these technologies currently come with disadvantages, namely noise pollution, information overload and alarm fatigue—all caused by too many alarms. Individual medical devices currently generate alarms independently, without any coordination or prioritisation with other devices, leading to a cacophony where important alarms can be lost amongst trivial ones, occasionally with serious or even fatal consequences for patients. We have called this approach to the design of medical devices the single-device paradigm, and believe it is obsolete in modern hospitals where patients are typically connected to several devices simultaneously. Alarm rates of one alarm every four minutes for only the physiological monitors (as recorded in the ICUs of two hospitals contributing to this p...

Thirty women presenting for major gynaecological oncology surgery under a standardized, combined epidural/general anaesthetic technique received either placebo or tenoxicam 20 mg intravenously, in a randomized double-blinded manner prior to surgery. Plasma and urinary electrolytes, creatinine, prostaglandins PgE2 and PgF1 alpha, and thromboxane (TxB2) were collected 12 hours preoperatively and then for four days postoperatively. There were no significant differences in any of the measured parameters between the groups, at any of the measurement times. Mean (SD) creatinine clearance at baseline, 24 h and 48 h was 100.4 (29.7) and 86.9 (27.5), 128.1 (45.9) and 115.0 (40.3), 137.5 (50.7) and 121.6 (38.6) in the placebo and tenoxicam groups respectively (P = 0.28). Both groups required similar amounts of intraoperative ephedrine and intravenous fluids to maintain blood pressure. The minimal changes in plasma and renal parameters reflect predictable responses to major surgery and rehydra...

A lumbar epidural catheter inserted in a 24-year-old woman for labour analgesia, and subsequently used for postcaesarean epidural analgesia, proved difficult to remove. After multiple attempts, the entrapped catheter was dislodged intact, revealing a knot near its distal tip. Knotting of an epidural catheter leading to entrapment is a rare complication of epidural catheterization.

The aim of this study was to define the anatomy relevant to brachial plexus regional anaesthesia and to identify the extent of variation between individuals. Surface ultrasound examination of the brachial plexus was performed on twenty volunteers. In the axilla there was considerable individual variation in the location of the median, radial and ulnar nerves in relation to the axillary artery. There was often more than one venous structure in this region, which was easily compressed by surface palpation. In the supraclavicular region, neural elements were located inferiorly to the subclavian artery in two volunteers. In one volunteer, a vein was identified between nerve trunks in the interscalene region. These findings indicate that the anatomical variation is considerable, even within the relatively small sample studied. For this reason, use of surface ultrasound may lead to increased success of brachial plexus regional anaesthesia and a decreased risk of intravascular injection.

Our aim was to evaluate end-of-life practices in a tertiary intensive care unit in Saudi Arabia. A prospective observational study was conducted in the medical-surgical intensive care unit of a teaching hospital in Riyadh, Saudi Arabia. Over the course of the one-year study period, 176 patients died and 77% of these deaths were preceded by end-of-life decisions. Of these, 66% made do-not-resuscitate decisions, 30% decided to withhold life support and 4% withdrew life support. These decisions were made after a median time of four days (Q1 to Q3: 1 to 9) and at least one day before death (Q1 to Q3: 1 to 4). The patients' families or surrogates were informed for 88% of the decisions and all decisions were documented in the patients' medical records. Despite religious and cultural values, more than three-quarters of the patients whose deaths were preceded by end-of-life decisions gave do-not-resuscitate decisions before death. These decisions should be made early in the patients...

A computer-based data storage and analysis system has been used to examine data obtained from 1257 patients admitted to an intensive care unit. The system readily provides administrative and clinical information which can be used to assess the workload, therapeutic efficiency and cost-effectiveness of such a unit. As the data-based expands, we expect that we will be able to identify sensitive predictors fo both complications and mortality and thereby permit the more efficient use of intensive therapy.

Intermediate-care or high-dependency units can provide a level of care that lies between the intensive care unit (ICU) and general ward, but the patients who are most likely to benefit from such level of care remains uncertain. This nested case-control study assessed the incidence and risk factors of high-dependency patients requiring ICU admission and whether these admissions were associated with a worse outcome when compared to other emergency ICU admissions. Seventy-seven consecutive high-dependency patients requiring ICU admission (cases) were compared with 77 patients who did not require ICU admission (controls) and also 928 emergency ICU admissions from other areas. The incidence of high-dependency patients requiring ICU admission was 6.7% (95% confidence interval 5.3 to 8.2). High-dependency admissions from the ward (odds ratio 4.46, 95% confidence interval 1.55 to 12.78) or emergency department (odds ratio 4.48, 95% confidence interval 1.54 to 13.0) and a need for concurrent...

The challenge to achieve a gestalt understanding of general anaesthesia is really dependent upon an understanding of the elusive concept of consciousness. Until very recently, anaesthesia has been understood to depend fundamentally on the lipid solubility of anaesthetic agents, unsurprisingly a misleading view which has followed from the greater simplicity of lipid chemistry compared with protein chemistry and, it is contended here, from a serious misunderstanding of the older experimental data. Nonetheless, because an over-simplistic view of lipids pertains in much pharmacological thinking about anaesthesia, this paper devotes some attention to potentially relevant aspects of lipid function and also to concepts of anaesthesia which are based on the properties of intracellular and extracellular water. It is argued that the more correct pharmacological explanation is likely to be action at hydrophobic sites of crucial functional molecules, most plausibly protein molecules: empirical ...

Interscalene blockade (ISB) is commonly associated with Horner's syndrome, indicating spread of injectate to the cervical sympathetic chain. Cervical sympathetic nerve activity (SNA) is believed to influence cerebral autoregulation, and a decrease in sympathetic tone may alter cerebral blood flow (CBF). This study investigated whether ISB influenced CBF in patients undergoing shoulder surgery. Patients (n=30) scheduled for elective shoulder arthroscopy were recruited. Cerebral oxygen saturation (ScO 2 ) of the left and right frontal cortices was continuously measured during ISB administration, sedation and anaesthetic induction. Baseline ScO 2 was similar in blocked and unblocked sides (74 ± 5% and 73 ± 5% respectively, P=0.70). ScO 2 decreased with sedation (-3 ± 3% and -4 ± 3%, P=0.93), and increased with pre-oxygenation and general anaesthesia (P <0.01). Following ISB there was no change in ScO 2 between blocked and unblocked sides (P=0.18), or any difference between right-or left-sided ISB. ISB is not associated with an increase in CBF as indicated by ScO 2 , despite the presence of Horner's syndrome.

Forty Chinese women for elective caesarean section received either propofol 2 mg.kg-1 or thiopentone 4 mg.kg-1 for induction of general anaesthesia. Systolic, mean and diastolic arterial pressures and heart rate were recorded non-invasively every minute for ten minutes. Post-induction arterial pressures were similar to pre-induction values with no differences between thiopentone and propofol. Following intubation, the rise in systolic arterial pressure was greater in the thiopentone group, 32.1 mmHg (SD 23.7) compared with the propofol group, 17.4 mmHg (SD 23.8), (P less than 0.05). In the thiopentone group, arterial pressures were slower in returning to baseline values. Heart rate was initially elevated in both groups to the same degree. At caesarean section, induction with propofol causes less variation in arterial pressure than thiopentone. Hypotension is probably prevented by the coincident stimulus of rapid sequence induction. Neonatal Apgar scores were similar between the two groups.

The manner in which elements of clinical history, physical examination and investigations influence subjectively assessed illness severity and outcome prediction is poorly understood. This study investigates the relationship between clinician and objectively assessed illness severity and the factors influencing clinician&#39;s diagnostic confidence and illness severity rating for ventilated patients with suspected pneumonia in the intensive care unit (ICU). A prospective study of fourteen ICUs included all ventilated admissions with a clinical diagnosis of pneumonia. Data collection included pneumonia type - community-acquired (CAP), hospital-acquired (HAP) and ventilator-associated (VAP), clinician determined illness severity (CDIS), diagnostic methods, clinical diagnostic confidence (CDC), microbiological isolates and antibiotic use. For 476 episodes of pneumonia (48% CAP, 24% HAP, 28% VAP), CDC was greatest for CAP (64% CAP, 50% HAP and 49% VAP, P&lt;0.01) or when pneumonia was c...

Trauma is the leading non-obstetric cause of maternal death. Optimal management of the pregnant trauma patient requires a multidisciplinary approach. The anaesthetist and critical care physician play a pivotal role in the entire continuum of fetomaternal care, from initial assessment, resuscitation and intraoperative management, to postoperative care that often involves critical care support and patient transfer. Primary goals are aggressive resuscitation of the mother and maintenance of uteroplacental perfusion and fetal oxygenation by the avoidance of hypoxia, hypotension, hypocapnia, acidosis and hypothermia. Recognizing and understanding the mechanisms of injury, the factors that may predict fetal outcome, and the pathophysiological changes that can result from trauma, will allow early identification and treatment of fetomaternal injury. This in turn should improve morbidity and mortality. A framework for the acute care of the pregnant trauma patient is presented.

Curt Schimmelbusch was born in Germany in 1860 and died only 35 years later leaving his name forever imprinted on the minds of anaesthetists-the Schimmelbusch mask being one piece of historical anaesthetic equipment most anaesthetists would recognise. Schimmelbusch was a surgeon in Berlin and was operating during a time of great change in surgery. In 1880 the germ theory of wound infection was finally proven, mainly due to the studies of Koch. A visitor to Berlin in 1882 asked the chief surgeon, Ernst Bergmann, what was new in surgery and was told' 'Today we wash our hands before operation"! Koch demonstrated that steam was a more effective sterilizer than carbolic acid and that it was also sporicidal. Thermal methods of sterilization were then adapted by Kiel who applied them to operating gowns and other surgical equipment. Schimmelbusch was a great believer in thermal sterilization and refined these methods to make them more practical. He and the French scientist, Terrier, created separately, but almost simultaneously, the steam sterilizer. Surgical instruments without wooden handles were also developed around this time by the German surgeon Neuber making thermal sterilization of instruments a more practical consideration. BIBLIOGRAPHY Duncum BM. The Development of Inhalational Anaesthesia. Oxford University Press. Bryn-Thomas K. The Development of Anaesthetic Apparatus.

The cardiovascular and haematological effects of purified prothrombin activator derived from the venom of the Australian Common Brown Snake (Pseudonaja textilis) were studied in anaesthetised, mechanically ventilated dogs. Severe depression of systemic blood pressure and cardiac output and a rise in central venous pressure were observed. Thrombocytopenia, prolongation of both prothrombin time and activated partial thromboplastin time and a reduction in serum fibrinogen were also observed. All of these observed effects were prevented by the prior administration of heparin--a naturally occurring anticoagulant. We conclude that the prothrombin activator in Pseudonaja textilis venom may cause cardiovascular depression due to myocardial dysfunction secondary to disseminated intravascular coagulation.

Methylene blue (aniline violet, tetra-methylthionine chloride) has several important uses in clinical medicine, including diagnosis of displaced central lines. After cardiac surgery, three infants with suspected displacement of direct atrial lines were given methylene blue. After injection of the dye into the atrial lines, bluish discolouration was identified in their chest drainage. Use of methylene blue in small amounts appears to be a safe and effective way of diagnosing extravasation of fluid from displaced central lines.

The efficacy of heparin therapy after subcutaneous injection of Common Brown Snake (Pseudonaja textilis) venom was studied in anaesthetised, mechanically ventilated dogs. Intravenous heparin (100 U/kg), administered fifteen minutes after envenomation, neither prevented nor hastened the recovery from cardiovascular depression and coagulopathy observed after venom administration. Heparin therapy is not recommended for the treatment of established human envenomation.

The measurement of thoracic electrical bioimpedance (TEB) offers a continuous, non-invasive method for monitoring cardiac output (CO). For clinical use, agreement with a current standard should be demonstrated. We describe a modification to the manufacturer&#39;s suggested data entry into the NCCOM3-R6 TEB monitor (BoMed Medical Manufacturing), which results in improved agreement with indocyanine green dye dilution (DD) CO estimation in paediatric patients. The manufacturer&#39;s instructions for the NCCOM3-R6 include an estimation of the volume of electrically participating thoracic tissue (VEPT) based on body weight. We also estimated the VEPT from direct anatomical measurement of thoracic length and circumference. The mean difference between paired DD and TEB CO using the manufacturer&#39;s weight-based instructions was 0.69 l/min with 95% confidence limits 2.34 to -0.96 l/min. The mean difference between the two CO techniques using our calculated VEPT was 0.35 l/min with 95% con...

The manner in which elements of clinical history, physical examination and investigations influence subjectively assessed illness severity and outcome prediction is poorly understood. This study investigates the relationship between clinician and objectively assessed illness severity and the factors influencing clinician&#39;s diagnostic confidence and illness severity rating for ventilated patients with suspected pneumonia in the intensive care unit (ICU). A prospective study of fourteen ICUs included all ventilated admissions with a clinical diagnosis of pneumonia. Data collection included pneumonia type - community-acquired (CAP), hospital-acquired (HAP) and ventilator-associated (VAP), clinician determined illness severity (CDIS), diagnostic methods, clinical diagnostic confidence (CDC), microbiological isolates and antibiotic use. For 476 episodes of pneumonia (48% CAP, 24% HAP, 28% VAP), CDC was greatest for CAP (64% CAP, 50% HAP and 49% VAP, P&lt;0.01) or when pneumonia was c...