bluuebunny/crossref_metadata_2025 huggingface dataset:
Synchronous distributed model predictive control for state-coupled systems
Authors: Yang Yuanqing , Ding Baocang
Published: January 2019

In this paper, we study distributed model predictive control (MPC) for the constrained system composed of a set of dynamically coupled subsystems. The proposed approach is based on the synchronous framework, so in each sub-controller, assumed state trajectories of its neighbours are involved, which are constructed by the optimal solutions at the previous sampling time. The compatibility constraint is imposed to bound the uncertain deviation between the assumed predictive trajectory and the true one. In addition, we use the constraint tightening technique in the predicted future evolutions to counteract this uncertain deviation which appears in the dynamics of each subsystem, so that physical constraints of the state and input are satisfied at each sampling time. By applying the proposed distributed MPC approach, the recursive feasibility and asymptotic stability of the overall system are guaranteed. An example is provided to verify the effectiveness and advantage of the result.
On the fractional closed-loop linear parameter varying system identification under noise corrupted scheduling and output signal measurements
Authors: Yakoub Zaineb , Amairi Messaoud , Aoun Mohamed , Chetoui Manel
Published: January 2019

It is well known that, in some industrial process identification situations, measurements can be collected from closed-loop experiments for several reasons such as stability, safety, and performance constraints. In this paper, we investigate the problem of identifying continuous-time fractional closed-loop linear parameter varying systems. The simplified refined instrumental variable method is developed to estimate both coefficients and differentiation orders. This method is established to provide consistent estimates when the output and the scheduling variable are contaminated by additive measurements noise. The proposed scheme is evaluated in comparison with other approaches in terms of a simulation example.
Unemployed Needn’t Apply: Unemployment Status, Legislation, and Interview Requests
Authors: Trzebiatowski Tiffany M. , Wanberg Connie R. , Dossinger Karyn
Published: January 2019

This research investigates whether and when a job applicant’s unemployment status (i.e., employed, short-term unemployed, or long-term unemployed) affects the probability of receiving an interview request by examining interview request rates in the presence of versus absence of unemployment status antidiscrimination legislation. In response to 3,335 fictitious resumes sent to 1,237 online job postings in Los Angeles and New York City, we received an overall interview request rate of 10.37. Long-term unemployed applicants were less likely to receive an interview request than short-term unemployed applicants in Los Angeles but not in New York City, which has unemployment status antidiscrimination legislation. These findings are supplemented with self-report survey data about perceptions of the unemployed from 200 hiring personnel in New York City and Los Angeles. Practical and theoretical implications are discussed for the unemployment, job search, and selection literatures.
How do radical right populist parties influence resurging debates over the stripping of citizenship?
Authors: Biard Benjamin
Published: January 2019

Debates over the stripping of citizenship have been rekindled in many countries in recent years. Radical right populist parties (RRPPs) are often perceived to have played a significant role in these resurging debates, even when they do not possess executive power and are often marginalised by mainstream parties. Thus, RRPPs’ real influence on policy-making remains unclear and the way RRPPs intervene in the policy-making process to influence it has not yet been satisfactorily determined. By focusing on policy-making, this study asks the question: how do RRPPs influence resurging debates over the stripping of citizenship? Using process-tracing and evidence from archives, memoirs and 67 interviews with policy-makers and party leaders, this research aims to determine if and how RRPPs intervene in the process in France and Belgium. The results indicate that RRPPs matter but that their influence is strongly curtailed. Their influence is not exercised directly and through institutional arenas, but indirectly: based on a provocative style, in a specific context, and through public opinion and the media.
Remaking Television: One Day at a Time’s Digital Delivery and Latina/o Cultural Specificity
Authors: del Río Esteban , Moran Kristin C.
Published: January 2019

New distribution models have transformed television over the past decade, and Netflix’s One Day at a Time (2017–) stands out not only because it is a remake of a classic Norman Lear sitcom, but because it also foregrounds a Cuban American family. Using a radical contextual and relational approach, this study analyzes One Day at a Time from a cultural studies perspective using theoretical tools that arrive from critical Latina/o communication studies. We analyze the first season’s 13 episodes to demonstrate how storytelling is modified in the context of digital streaming. In this case, we argue that One Day at a Time offers an alternative to the flattening of difference far too common in Latina/o media. Instead, the show highlights the cultural specificity of this Cuban American family as a form of broad audience appeal as it negotiates sexual identity and immigration discourses within a contemporary social framework.
Acute otitis media associated with Gradenigo syndrome and transverse sinus thrombosis: a case report
Authors: Özkaçmaz Sercan
Published: January 2019

Gradenigo syndrome is associated with middle ear infection that extends to the petrous apex, leading to pain at the innervation site of the ophthalmic and maxillary branches of the trigeminal nerve and the development of abducens nerve palsy. Cerebral venous sinus thrombosis is a serious neurological complication of otitis media and occurs secondary to spread of the infection to the underlying bone. We herein report a pediatric case of otitis media associated with Gradenigo syndrome and ipsilateral sigmoid–transverse sinus thrombosis with magnetic resonance imaging findings.
Ferdinand von Richthofen’s loess research in China
Authors: Fei Jie , Pei Qing
Published: January 2019

Ferdinand von Richthofen (1833–1905), a great German geographer and geologist, was well known for his loess research in China. Here we reexamine the background of Richthofen’s loess research and review his contributions and limitations according to the existing literature. An important historical background of Richthofen’s loess research was that foreigners have been authorized to travel in the interior of China since the 1860s as a result of the Treaties of Tientsin. Richthofen made seven comprehensive scientific explorations in China in 1868–1872, whereas loess research was just one of his topics. He experienced dust weather on the Loess Plateau, where he had direct and deep impressions of the transport of dust, which should have helped him develop the hypothesis of the Aeolian origin of loess. Apart from the Aeolian hypothesis, his other achievements include the differentiation of the regenerated loess from the original loess, the discovery of the loess near Nanjing, the identification of the desiccated lakes as sources of dust storms, and the identification of “vertical cleavage” as a major property of loess.
The Effect of Nitrous Oxide on Hearing
Authors: Fabijan D. J. , Morris R. , Murray G. M.
Published: January 2019

There is a belief that the administration of nitrous oxide (N 2 O) increases hearing acuity. This increase can be interpreted as hearing low intensity sounds more loudly. This study examined auditory threshold levels, acoustic impedance, acoustic perception, memory, and discrimination to determine if hearing was altered by end-tidal 10% or 20% nitrous oxide. Subjects also qualitatively interpreted three intensity levels using a subjective intensity test. Observations were made in the breathing mediums of room air in the control stages (Stages 1 and 4), compared to N 2 O and supplemental oxygen (Stages 2 and 3), in 16 human subjects in a quiet room. Breathing end-tidal 10% and 20% N 2 O significantly increased middle ear pressure, and produced a significant effect on the subjective interpretation of a sound's intensity. There was no significant effect on auditory threshold at a range of frequencies. It appears that 10% or 20% N 2 O inhalation does not lead to the commonly held view of increased hearing acuity as measured in terms of auditory threshold. Rather, at these levels of N 2 O inhalation, subjects experience a state similar to a pre-sleep stage, whereby the hearing diminishes but remains active for loud intensity sounds.
Pethidine Reverses Morphine-Induced Delirium
Authors: McLoughlin P. D.
Published: January 2019

A young patient had unexpected and prolonged postoperative delirium apparently associated with morphine-induced biliary colic. Naloxone had no therapeutic effect, but a small dose of pethidine produced a dramatic return to lucidity. Unrecognized biliary spasm should be considered as a cause of agitation in the recovery room in postoperative patients who have received morphine.
Re-Wiring an Arterial Line. A Novel Technique
Authors: Nickells J. , Res J. , Mitchell I. A.
Published: January 2019

In cases where the loss of a small volume of blood is critical to the patient's welfare, the technique of re-wiring intra-arterial and intravenous catheters that minimize the amount of blood lost is important. A simple technique is described using the needleless systems which are now widely employed throughout hospitals.
Postoperative Sore Throat and Hoarseness following Tracheal Intubation Using Air or Saline to Inflate the Cuff—A Randomized Controlled Trial
Authors: Bennett M. H. , Isert P. R. , Cumming R. G.
Published: January 2019

Sore throat and hoarseness following tracheal intubation is common. The aetiology may include high tracheal cuff pressures. We performed a double-blind, randomized controlled trial in 126 intubated patients to compare the incidence and severity of sore throat and hoarseness following inflation of the cuff using air or saline. Intra-cuff pressures were compared to assess any change due to inward diffusion of nitrous oxide. The incidence of significant sore throat and/or hoarseness overall was 15.0%. There was no statistically significant difference between the groups (air 15.9%, saline 14.5%). In the air group mean intra-cuff pressure increased significantly (start 14.0 mmHg, end 40.9 mmHg), while in the saline group there was no significant increase (start 12.7 mmHg, end 14.6 mmHg). The substitution of saline reliably results in sustained low intra-cuff pressures but high tracheal cuff pressure is not an important factor in the development of sore throat or hoarseness postoperatively within the pressure range and duration of operation studied.
Leptospirosis Complicated by Severe Aortic Stenosis
Authors: Butler C. S. , Endara S. A.
Published: January 2019

A previously well 62-year-old male from North Queensland presented with leptospirosis featuring fever, renal failure, hepatitis and pulmonary haemorrhage. Management was greatly complicated by severe and previously unrecognized aortic stenosis with a peak valve gradient of 125mmHg. A successful outcome followed careful haemodynamic management and treatment of the infective illness with subsequent valve replacement.
The Treatment of Tetanus with Intrathecal Baclofen
Authors: Boots R. J. , Lipman J. , O'Callaghan J. , Scott P. , Fraser J.
Published: January 2019

The treatment of severe tetanus generally requires prolonged mechanical ventilation. We describe two cases managed with continuous intrathecal infusion of baclofen via a subcutaneous tunnelled spinal catheter and an abdominal injection port. Baclofen, by diminishing spasms and spasticity, allowed reduced sedation and paralysis requirements. This potentially decreases the time and resources required for intensive care management. Complications include sedation, hypotension and CSF infection. After appropriate dose adjustment, baclofen improves the management of severe tetanus.
Tracheal Foreign Body following Tube Change during Percutaneous Dilational Tracheostomy: A Cautionary Tale
Authors: Pinder M. , Cameron P. D. , Lovegrove A.
Published: January 2019

Although studies have shown percutaneous dilational tracheostomy to be a safe and cost-effective alternative to conventional surgical tracheostomy, there are inherent risks and complications. We report an incident occurring during percutaneous dilational tracheostomy using the Portex technique, in which a significant cuff leak occurring on insertion of the tracheostomy tube necessitated an immediate tube change. During this latter procedure, using a fresh Portex kit and guidewire, the guidewire introducer became dislodged from the guidewire assembly and inadvertently impacted in the trachea. Routine bronchoscopy identified the hazard and the foreign body was successfully removed via the bronchoscope with no adverse sequelae.
Swelling and Cyanosis of the Tongue Associated with Use of a Laryngeal Mask Airway
Authors: Twigg S. , Brown J. M. , Williams R.
Published: January 2019

We present a case report of a patient who developed acute swelling of the tongue during anaesthesia using the laryngeal mask airway. The swelling was thought to be due to obstruction of the venous drainage of the tongue. This was associated with isolated cyanosis of the tongue and paraesthesia. The swelling and cyanosis of the tongue resolved rapidly after removal of the laryngeal mask airway. The patient suffered paraesthesia of the tip of the tongue that lasted for two weeks.
Spinal Anaesthesia in a Patient with Epidermolysis Bullosa Dystrophica
Authors: Patch M. R. , Woodey R. D.
Published: January 2019

An adult patient with epidermolysis bullosa dystrophica underwent uneventful spinal anaesthesia. Insertion of a Quincke spinal needle proved easier and produced less skin distortion than insertion of a pencil-point spinal needle. Taping of intravenous lines is an alternative to the more usually recommended approach of suturing.
Cardiovascular and Pulmonary Effects of Epidural Anaesthesia
Authors: Veering B. T. , Cousins M. J.
Published: January 2019

Epidural anaesthesia has been used since the early 1900s. Consequently the general characteristics of these procedures have been well defined. More studies have provided a better understanding of the cardiopulmonary changes produced by epidural anaesthesia.

The cardiovascular effects observed with epidural anaesthesia are complex and variable, depending on a multitude of factors. The extent of sympathetic denervation, balance of sympathetic and parasympathetic activity, the pharmacological effect of systemically absorbed local anaesthetic agents, inclusion of adrenaline in the anaesthetic solution, the distribution of blood in relation to cardiac filling and cardiovascular function of the patient must be taken into account when considering the circulatory effects of epidural anaesthesia. Individual cardiovascular response to different levels of sympathetic blockade varies widely, depending on the degree of sympathetic tone before the block. Epidural anaesthesia that is restricted to the level of the low thoracic and lumbar region (T5-L4) results in a “peripheral” sympathetic blockade with vascular dilatation in the pelvis and lower limbs. High thoracic epidural anaesthesia, from the first to fifth thoracic, blocks the cardiac afferent and efferent sympathetic fibres with loss of chronotropic and inotropic drive to the myocardium.

Thoracic epidural anaesthesia appears to at least partly reverse the diaphragmatic dysfunction that is a major determinant of the decrease in lung volumes observed after upper abdominal surgery.

This article summarizes cardiovascular and pulmonary responses to epidural anaesthesia. Details of clinical management are not included in the review.
Relative Cost of Autologous Red Cell Salvage versus Allogeneic Red Cell Transfusion during Abdominal Aortic Aneurysm Repair
Authors: Gardner A. , Gibbs N. , Evans C. , Bell R.
Published: January 2019

The costs of washed autologous red cell concentrate obtained by intraoperative red cell salvage were compared to the costs of allogeneic packed red cell transfusion during 110 consecutive abdominal aortic aneurysm repairs. The mean volume of scavenged blood during elective procedures was 1350 ml (range 350 to 6675 ml, n=90) and emergency procedures 2750 ml (range 750 to 9400 ml, n=20). The mean volume of processed (washed) blood returned during elective repairs was 759 ml (range 150 to 2900 ml, n=51) and emergency repairs 1117 ml (range 0 to 4100 ml, n=20). During elective repairs, the cost of routine autologous red cell salvage ($151 per 285 ml unit) was only slightly greater than the estimated cost of cross-matched, leucocyte-reduced, allogeneic blood ($143 per 285 ml unit). During emergency repairs, washed autologous red cells ($83 per 285 ml unit) were less expensive than allogeneic packed red cells. These findings indicate that, compared with the use of allogeneic packed red cells, red cell salvage during emergency abdominal aortic aneurysm repair can be justified on an economic basis alone, and that routine red cell salvage during elective repair can achieve the benefits of autologous blood at little extra cost to the community.
Plasma Soluble Interleukin-2 Receptor Levels during and after Upper Abdominal Surgery
Authors: Kato M. , Kurosawa S. , Matsuoka H. , Murakami M. , Imai R. , Takahashi M.
Published: January 2019

Soluble interleukin-2 (IL-2) receptor (sIL-2R) is reported to be up-regulated in inflammatory disorders. Although sIL-2R may modulate perioperative inflammatory responses, it remains unclear whether upper abdominal surgery affects plasma sIL-2R levels. We evaluated the influence of major abdominal surgery on plasma sIL-2R levels. Ten patients scheduled for upper abdominal surgery received anaesthesia with isoflurane, nitrous oxide, and epidural block. Plasma sIL-2R and IL-6 levels were determined at pre-anaesthesia, 0, 2, and 4 hours during surgery, and on postoperative days 1 (POD1) and 3 (POD3). The plasma levels of sIL-2R decreased significantly and achieved their minimum value at 4 hours (677.0±125.3 pg/ml, P<0.01 compared to pre-anaesthesia value; 924.5±178.8 pg/ml, 95% confidence interval=122.2–550.4). The plasma sIL-2R levels increased on POD1 (1336.5±174.0 pg/ml) and POD3 (1629.0±262.8 pg/ml), and reached a level significantly higher than the baseline (P<0.05 and P<0.001, 95% confidence interval=93.4–730.6 and 402.8–1006.2, respectively). The plasma sIL-2R levels on POD3 significantly correlated with the peak IL-6 levels (r=0.67, P<0.05). The plasma sIL-2R levels on POD3 correlated with the amount of intraoperative bleeding (r=0.66, P<0.05). In conclusion, we found that major abdominal surgery induces characteristic changes in plasma soluble IL-2 receptor levels.
Can Insertion Length for a Double-Lumen Endobronchial Tube be Predicted?
Authors: Dyer R. A. , Heijke S. A. M. , Russell W. J. , Bloch M. B. , James M. F. M.
Published: January 2019

It has been suggested that the appropriate length of insertion for double-lumen tubes can be estimated by external measurement. This study examined the accuracy of external measurement in estimating the actual length of insertion required in 130 patients. It also examined the relationship between the length inserted and the patient's height in 126 patients and their weight in 125 patients.

Although there was a fair correlation between the measured external length and the final inserted length (r=0.61), the 95% confidence intervals of slope and intercept allowed a large variation and the prediction was too wide to be clinically useful. Height was reasonably well correlated with the final length (r=0.51) but an equally wide 95% confidence interval rendered it of little clinical value. There was no correlation between weight and final tube length.

It is concluded that external measurement alone is not adequate to predict a clinically acceptable position of the double-lumen tube.
Patient Care Bridge—Mobile ICU for Transit Care of the Critically Ill
Authors: Nagappan R. , Riddell T. , Barker J. , Maiden N. J. , Lindsay S.
Published: January 2019

We describe the development and introduction of a Patient Care Bridge—a mobile ICU for the transit care of the critically ill. This stretcher-mounted Patient Care Bridge is being used for intensive transit care of the critically ill in Northland, New Zealand. It carries all the basic intensive care monitoring accoutrements, is lightweight and is suited for pre-hospital, inter-hospital and intra-hospital transit care. It is ideal for patient evacuation from the scene of motor vehicle and sporting accidents, surface transportation of patients by surface ambulance and aeroevacuation of patients by the Helicopter Emergency Medical Service.

This economic and space efficient unit has been used for transfer of more than one thousand critically ill patients.
Attitudes and Practices of New Zealand Anaesthetists with Regard to Emergency Drugs
Authors: Ducat C. M. , Merry A. F. , Webster C. S.
Published: January 2019

A postal survey of anaesthetists practising in New Zealand assessed practices with regard to the preparation of pre-drawn syringes of emergency drugs in theatre, and attitudes towards the drawing up of drugs by non-medically qualified assistants. Opinion and practice varied widely; a quarter of respondents routinely draw up such drugs and a third either never or very infrequently do so. The drugs most commonly drawn up in this way were suxamethonium, atropine, syntocinon, ephedrine and metaraminol. Providing anaesthesia single-handed, anaesthesia involving paediatric, obstetric or vascular cases, the use of major regional techniques and laryngeal mask anaesthesia were reported as factors which prompted a number of respondents to draw up one or more of these drugs. The majority (68.5%) had received no teaching on the issue and nearly all (83.5%) reported that there was no institutional policy in their workplace(s). “Syringe swap” or “wrong drug” errors related to such pre-drawn drugs were reported by 26.5%, while delay in drawing up a drug in an emergency was reported by 37%. Nearly all (98%) respondents believed that it was acceptable for an anaesthetic technician (or similar assistant) to draw up drugs in an emergency but only 14% approved of assistants drawing up drugs routinely. We conclude that there is no uniformity of opinion amongst New Zealand anaesthetists about which if any drugs should be pre-drawn for possible emergency use, and that few would endorse the drawing up of drugs by non-medically qualified assistants, except in emergency, or under other clearly delineated circumstances.
Intraoperative High-Dose Remifentanil in a Patient on Naltrexone Therapy
Authors: Schwab C. A. , Wright D. A.
Published: January 2019

Naltrexone hydrochloride is a synthetic opioid receptor antagonist recently used in efforts to provide rapid opioid detoxification. Other clinical uses include alleviating itch due to cholestasis or uraemia. We report a case where unrecognised naltrexone therapy for itch affected anaesthesia, resulting in high opioid requirements. We also discuss other analgesic options utilized.
Anaesthesia for Amiodarone-Induced Thyrotoxicosis: A Case Review
Authors: Sutherland J. , Robinson B. , Delbridge L.
Published: January 2019

Amiodarone-induced thyrotoxicosis is a life-threatening problem that is very effectively managed by total thyroidectomy, although often many of these patients are considered “too unfit” for anaesthesia. The aim of this study was to review the safety of anaesthesia for total thyroidectomy in the acute management of amiodarone-induced thyrotoxicosis.

Information was obtained retrospectively from a prospective endocrine surgical database and from hospital records. Data, including outcomes and morbidity, are presented from 12 patients who underwent anaesthesia for total thyroidectomy as an urgent procedure for amiodarone-induced thyrotoxicosis.

Despite the fact that these patients had uncontrolled thyrotoxicosis and marked cardiac failure at the time of anaesthesia, no anaesthetic or surgical mortality was seen. We conclude that a challenging patient with amiodarone-induced thyrotoxicosis that has not responded to conservative measures may be considered for total thyroidectomy early in their management. Total thyroidectomy can be performed under general or local anaesthesia with apparent relative safety.
The Use of Thiopentone/Propofol Admixture for Laryngeal Mask Airway Insertion
Authors: Yeo K. S. J. , Kua S. W. J. , Teoh G. S. , Onsiong M. K. S.
Published: January 2019

An admixture of thiopentone and propofol was evaluated against propofol for laryngeal mask airway (LMA) insertion. Eighty-one ASA 1 and 2 18- to 65-year-old patients, premedicated with 7.5 mg midazolam orally were assigned randomly to receive either propofol 1% or an admixture of thiopentone and propofol (1.25% and 0.5% respectively), both at a dose of 0.25 ml.kg–1. Satisfactory conditions for insertion were achieved with the admixture, which was comparable to propofol (73% vs 85%, P>0.05). There was no statistical difference in the incidence or severity of gagging, coughing, inadequate jaw relaxation and laryngospasm. The incidence of hypotension was lower in the admixture group (51% vs 78%, P=0.02). The duration of apnoea was not different between the admixture and propofol group (mean 103s vs 109 s respectively, P>0.05). We conclude that thiopentone/propofol admixture can be a suitable alternative to propofol for LMA insertion, producing less hypotension while allowing cost savings of up to 45%.

An admixture of thiopentone and propofol (1.25% and 0.5% respectively) can produce suitable conditions compared to propofol 1%, for laryngeal mask insertion. In addition to cost containment, the admixture also produces less hypotension.
Anaesthesia in a Child with Autosomal Recessive Omodysplasia
Authors: Di Luca B. J. , Mitchell A.
Published: January 2019

A child with a recently described form of dwarfism, autosomal recessive omodysplasia, presented for general anaesthesia for dental conservation. Despite the patient's dysmorphic features and craniofacial and mandibular deformities, no significant anaesthetic problems were encountered. Anaesthetic implications of the condition are reviewed.
Do Anaesthetists Need to Wear Surgical Masks in the Operating Theatre? A Literature Review with Evidence-Based Recommendations
Authors: Skinner M. W. , Sutton B. A.
Published: January 2019

Many operating theatre staff believe that the surgical face mask protects the healthcare worker from potentially hazardous biological infections. A questionnaire-based survey, undertaken by Leyland1 in 1993 to assess attitudes to the use of masks, showed that 20% of surgeons discarded surgical masks for endoscopic work. Less than 50% did not wear the mask as recommended by the Medical Research Council. Equal numbers of surgeons wore the mask in the belief they were protecting themselves and the patient, with 20% of these admitting that tradition was the only reason for wearing them.

Policies relating to the wearing of surgical masks by operating theatre staff are varied. This indicates some confusion about the role of the surgical mask in modern surgical and anaesthetic practice. This review was undertaken to collate current evidence and make recommendations based on this evidence.
Prolonged Thiopentone Infusion for Neurosurgical Emergencies: Usefulness of Therapeutic Drug Monitoring
Authors: Cordato D. J. , Herkes G. K. , Mather L. E. , Gross A. S. , Finfer S. , Morgan M. K.
Published: January 2019

Serial serum thiopentone concentrations were measured during and following completion of an intravenous infusion of thiopentone in 20 patients with neurosurgical emergencies. The concentration data from a further 55 patients who had had some such measurements were reviewed retrospectively. The patients received an infusion for longer than 24 hours at a rate adjusted to maintain EEG burst suppression. The data were interpreted in terms of thiopentone pharmacokinetics and used to produce statistical models relating to clinical outcomes. In these patients, the one-month mortality rate following commencement of thiopentone treatment was 20%; the mean durations of pupillary and motor unresponsiveness following cessation of an infusion were 22 and 91 hours, respectively. Predictors of a prolonged duration of motor unresponsiveness included a prolonged duration of pupillary unresponsiveness, a low thiopentone clearance and a high maximum serum concentration of thiopentone. From pooled logistic regression, median effective serum thiopentone concentrations (EC50) were found to be 50 mg.l–1 for recovery of pupillary responsiveness and 12 mg.l–1 for the recovery of motor responsiveness. Because prolonged high-dose thiopentone leads to prolonged residual serum concentrations, it is difficult to distinguish the residual pharmacological effects of thiopentone from the clinical condition. This study suggests that, based on EC50 values for responses, monitoring of post-infusion serum thiopentone concentrations may help determine whether a patient's clinical state is due to residual thiopentone pharmacological effects.
Relationship between Work of Breathing Provided by a Ventilator and Patients’ Inspiratory Drive during Pressure Support Ventilation; Effects of Inspiratory Rise Time
Authors: Uchiyama A. , Imanaka H. , Taenaka N.
Published: January 2019

Inspiratory drive and work of breathing provided by a ventilator (WOBv) during pressure support ventilation (PSV) were examined in 15 patients. At PSV 10 and 15 cm H 2 O during CPAP 5 cm H 2 O, patients with low P 0.1 (<4.2 cm H2 O, n=9) showed WOBv 0.57 and 0.92 J/l, those with high P 0.1 (>4.2 cm H 2 O, n=6) showed 0.31 and 0.62 J/l respectively. WOBv was smaller and pressure-time product of oesophageal pressure (PTP) was significantly larger in high P 0.1 patients. Peak inspiratory flow for low P 0.1 patients increased as PSV level increased but high P 0.1 patients showed no significant change. In a lung model, effects of inspiratory rise time (IRT) and PSV were studied at high and low inspiratory drives by using ventilators with (Servo 300) and without (Mallinckrodt 7200a) adjustable IRT. With 7200a, PSV 10 cm H 2 O during low drive was compared with PSV 10 and 15 cm H 2 O during high drive. In Servo 300, PSV 10 cm H 2 2O (IRT 0.6 and 0.0 sec) during low drive was compared with PSV 10 cm H 2 O (IRT 0.6 and 0.0 sec) and PSV 15 cm H 2 O (IRT 0.6 sec) during high drive. Raising PSV and shortening IRT both increased peak inspiratory flow. Initial inspiratory flow increased in inverse proportion to IRT, but higher PSV had a little effect. WOBv with high drive was less than with low drive. Higher PSV preserved WOBv by increasing tidal volume. Shortening IRT recruited WOBv by increasing initial inspiratory flow without changing airway pressure and tidal volume. Compared with higher PSV, shorter IRT reduced PTP more. In conclusion, WOBv decreased as inspiratory drive increased due to inability to increase inspiratory flow. Increasing initial inspiratory flow was more effective than raising PSV to preserve inspiratory assistance of PSV at high inspiratory drive.
Sensitivity of Action Potential Triggering is Normally Distributed as a Function of Mean Fractional Receptor Activation
Authors: Santanen O. A. P. , Paloheimo M. P. J.
Published: January 2019

In 1968, Waud presented his general pharmacodynamic model consisting of two sub-functions that divide the pharmacodynamic cascade from drug concentration to cell effect/response into two successive steps: Step one (the internal function) characterizes the binding of agonist drug molecules to the post-synaptic receptors and the subsequent receptor activation, and step two (the external/effect function) characterizes the cell response induced by a critical receptor pool activation. According to Waud, the problem of determining the relation between drug concentration and cell response/effect reduces to the second step in the pharmacodynamic cascade. In this paper, we suggest a new external/effect-function, the cumulative Normal population-effect-function. It describes how muscle fibre excitability (all-or-none phenomenon) is distributed as a function of mean fractional receptor activation in a muscle fibre population. This function fits to empirical data and explains logically why the sigmoid muscle effect, from minimal to maximal, is seen in such a narrow range of antagonist concentrations and receptor occupancies.
Vasopressin and Shock
Authors: Forrest P.
Published: January 2019

Vasopressin (antidiuretic hormone) is emerging as a potentially major advance in the treatment of a variety of shock states. Increasing interest in the clinical use of vasopressin has resulted from the recognition of its importance in the endogenous response to shock and from advances in understanding of its mechanism of action. From animal models of shock, vasopressin has been shown to produce greater blood flow diversion from non-vital to vital organ beds (particularly the brain) than does adrenaline. Although vasopressin has similar direct actions to the catecholamines, it may uniquely also inhibit some of the pathologic vasodilator processes that occur in shock states.

There is current interest in the use of vasopressin in the treatment of shock due to ventricular fibrillation, hypovolaemia, sepsis and cardiopulmonary bypass. This article reviews the physiology and pharmacology of vasopressin and all of the relevant animal and human clinical literature on its use in the treatment of shock following a MEDLINE (1966–2000) search.
Functional Iron Deficiency, Infection and Systemic Inflammatory Response Syndrome in Critical Illness
Authors: Patteril M. V. , Davey-Quinn A. P. , Gedney J. A. , Murdoch S. D. , Bellamy M. C.
Published: January 2019

To investigate the prevalence and clinical relevance of functional iron deficiency in the critically ill, we performed a prospective observational study in a university hospital general intensive care unit. We collected patient demographics, severity of illness data, haematological and biochemical variables in 51 consecutive admissions. We recorded episodes of culture-positive infection.

Functional iron deficiency (FID), measured by red cell hypochromasia on flow cytometry, was present in 35% of patients at admission to intensive care. FID patients were of similar age, diagnosis, APACHE score, sequential organ failure assessment (SOFA) score, haemoglobin, serum B12, folate and ferritin to patients without FID. However, patients with FID had a prolonged intensive care stay compared with non-FID patients (P<0.001) and increased time to hospital discharge (P=0.09). Duration of intensive care stay correlated with severity of FID (r=0.33, P<0.02). Systemic inflammatory response syndrome (SIRS) was present for longer in those with FID (P<0.02). Overall mortality did not differ between groups. No difference was seen in the incidence of positive cultures between those with FID (9/18 patients) and those without FID (15/33 patients). FID was independently associated only with abnormal white blood cell count (WBC <4 or >11x109.l-1) at admission to ICU, P=0.007, but not with positive cultures.

There is a high prevalence of FID in intensive care, associated with an increased duration of stay and duration of SIRS. We have been unable to demonstrate a link with infection, either as a predisposing factor or as an acute response.
A Spoonful of Sugar—Improving the Sensitivity of the Glucose Oxidase Test Strip Method for Detecting Subclinical Pulmonary Aspiration of Enteral Feed
Authors: Young P. J.
Published: January 2019

A 74-year-old woman was admitted to the intensive care unit (ICU) with respiratory failure. Following intubation and mechanical ventilation, nasogastric enteral feeding was begun. The sensitivity of the glucose oxidase strip method for detecting aspiration of enteral feed has been questioned because the glucose levels in commonly used feeds are similar to those of normal tracheal aspirates. In order to increase the glucose concentration of the feed, 10g of glucose was added to each 500 ml feed carton. Testing oral and tracheal secretions with standard glucose oxidase strips allowed the accurate detection of both pharyngeal regurgitation and tracheal aspiration.

An episode of subclinical aspiration was detected and this was associated with a fall in the PaO2/FiO2 ratio. There were no further episodes of aspiration following the introduction of a gastric motility agent, maintaining the patient in the semi-recumbent position and an increase in the positive end expiratory pressure (PEEP).
The Bispectral Index during an Anaphylactic Circulatory Arrest
Authors: Kluger M. T.
Published: January 2019

A 47-year-old woman with Cushing's syndrome suffered a severe anaphylactic reaction on induction of anaesthesia, resulting in circulatory arrest. A spontaneous cardiac output appeared after 25 minutes of chest compression and she regained consciousness three hours later, with no neurological deficit. A Bispectral Index monitor demonstrated values greater than 40 throughout the whole period of resuscitation. Possible implications for this observation are discussed.
Non-Bronchoscopic Bronchoalveolar Lavage in the Microbiological Diagnosis of Pneumonia in Mechanically Ventilated Patients
Authors: Arora S. C. , Mudaliar Y. M. , Lee C. , Mitchell D. , Iredell J. , Lazarus R.
Published: January 2019

A prospective study comparing standardized non-bronchoscopic bronchoalveolar lavage (sNB-BAL) and nonspecific endotracheal aspirate (NsETA) in the microbiological diagnosis of pneumonia in mechanically ventilated patients is described. One hundred episodes in 82 mechanically ventilated patients with or without radiological and clinical diagnostic criteria of pneumonia were studied. NsETA and sNB-BAL was performed on the day of study. Fifty-one patients had pneumonia (21 ventilator-associated, 12 hospital-acquired, 18 community-acquired) and 49 had no pneumonia as defined by widely accepted clinico-radiological criteria. The sNB-BAL was found to be significantly more specific (0.73) compared to NsETA (0.35) for the microbiological diagnosis of pneumonia. Colonization rates with NsETA were significantly higher compared to sNB-BAL (P value < 0.0001). No patient had complications attributable to the sNB-BAL procedure. We conlude that sNB-BAL is a safe, effective, sensitive, specific and inexpensive procedure for the serial evaluation of pneumonia in mechanically ventilated patients.
Accuracy of Portable Infusers under Hyperbaric Oxygenation Conditions
Authors: Dohgomori H. , Arikawa K. , Gushiken T. , Kanmura Y.
Published: January 2019

Three types of portable infusers with different infusion mechanisms were evaluated with regard to their accuracy during a hyperbaric oxygenation protocol. The power driving the pump is provided by either a balloon, a spring or a vacuum mechanism. Performance during hyperbaric oxygenation (HBO) varied between the devices, probably due to the difference in driving mechanism. Flow delivery by the vacuum type infuser is substantially affected by HBO. Doubling the ambient pressure approximately doubled flow delivery from the vacuum type device. We suggest that other devices are more suitable for use in this clinical situation. We conclude that it is desirable to check the performance of any infuser intended for use during hyperbaric oxygenation and to be mindful of potential differences among such devices.
Incidents Relating to Arterial Cannulation as Identified in 7525 Reports Submitted to the Australian Incident Monitoring Study (AIMS—ICU)
Authors: Durie M. , Beckmann U. , Gillies D. M.
Published: January 2019

Arterial cannulation is frequently used in the critical care environment. Literature focuses on insertion techniques and complications. This report utilized data from the Australian Incident Monitoring Study (AIMS-ICU) national database to identify common problems and contributing factors associated with the use and maintenance of arterial lines. A review of narratives, keywords and contributing factors yielded 251 reports outlining 376 incidents. Of these, 15% describing line insertion problems, 66% line use and maintenance problems and 19% patient injuries. Inadequate line securing, accidental line dislodgement, incorrect set-up, distal ischaemia and infection featured prominently. As a result of the incident, 49% of patients involved suffered no ill effect, 28% minor physiological complications and 15% suffered major adverse effects. Multiple contributing factors were selected for each report, with lack of knowledge, rule-based errors, high unit activity, and lack of support staff or supervision selected most frequently. This study highlights the need to employ meticulous insertion technique, line set-up, securing, frequent line assessment and the early removal of lines no longer essential to patient care. Support and education of staff as well as the development of protocols are important for the safe use of arterial lines.
Anaesthesia for Endoluminal Repair of Abdominal Aortic Aneurysms
Authors: Davies M. J. , Arhanghelschi I. , Grauer R. , Heard G. , Scott D. A.
Published: January 2019

An audit of 100 patients undergoing elective abdominal aortic surgery either by open aortic repair (OAR group 50 patients) or endovascular aortic repair (EAR group 50 patients) was undertaken to document changes in anaesthetic technique and perioperative outcome. The data for the OAR group was collected retrospectively and that for the EAR group prospectively. Combined general anaesthesia and thoracic epidural anaesthesia was used in 44 of the OAR group whereas lumbar central neural blockade alone was used in 47 of the EAR group. The major differences between the two groups were that intraoperative blood loss was significantly less in the EAR group (OAR 1674±1008 ml, EAR 459±350 ml, P<0.001) and that no patient in the EAR group required admission to the Intensive Care Unit (ICU), whereas ICU time for the OAR patients was 29±22 hours. Hospital stay was also significantly different between the two groups (OAR 13±6 days, EAR 5±3 days, P<0.001). Major complications occurred in 20 patients in the OAR group but only 4 patients in the EAR group (P<0.001). EAR reduces blood loss, the requirement for ICU admission, and hospital stay. Central neural blockade is a satisfactory anaesthetic technique for EAR.
Phaeochromocytoma and Acute Myocardial Infarction
Authors: Biccard B. M. , Gopalan P. D.
Published: January 2019

Phaeochromocytoma is uncommonly associated with myocardial infarction. We present a patient who, despite established alpha adrenoceptor blockade, sustained an acute myocardial infarction and was found to have coronary artery disease. Indications for coronary revascularization were not met, and adrenalectomy was successfully performed four weeks later. Factors contributing to the myocardial infarction, the role of beta adrenoceptor blockade, the timing of adrenalectomy and the place of coronary revascularization are discussed.
Awake Fibreoptic Intubation under Remifentanil and Propofol Target-controlled Infusion
Authors: Donaldson A. B. P. , Meyer-Witting M. , Roux A.
Published: January 2019

We present the first report of the use of remifentanil and propofol target-controlled infusion to sedate a patient with a difficult airway undergoing awake fibreoptic intubation. This regimen was rapidly titratable, aided suppression of airway reflexes, maintained patient comfort and cooperation and did not compromise spontaneous respiration. The literature regarding infusion rates and potential complications of this technique is reviewed.
Monitoring Neuromuscular Transmission
Authors: Torda T. A.
Published: January 2019

Persistent neuromuscular blockade is not uncommon in the recovery room and contributes to postoperative morbidity and possibly mortality. The use of neuromuscular monitoring and intermediate rather than long-acting neuromuscular blocking drugs have been shown to reduce its incidence. Clinically available methods of detecting and quantitating neuromuscular blockade are reviewed. The writer concludes that such monitoring should be routine when neuromuscular blocking drugs are used.
Pharmacological Principles of Antibiotic Prescription in the Critically Ill
Authors: Pinder M. , Bellomo R. , Lipman J.
Published: January 2019

The goal of antimicrobial prescription is to achieve effective drug concentrations. Standard antimicrobial dosing regimens are based on research performed often decades ago and for the most part with patients who were not critically ill. More recent insights into antibiotic activity (e.g. the importance of high peak/MIC ratios for aminoglycosides and time above MIC for β-lactam antibiotics), drug pharmacokinetics (e.g. increased volume of distribution and altered clearances) and the pathogenesis of sepsis (e.g. third space losses and altered creatinine clearances) have made re-evaluation of dosing regimens necessary for the critically ill.

The inflammatory response associated with sepsis results in a rapid decrease in serum albumin levels, large fluid shifts and third space losses, initially with a high cardiac output. In turn these changes result in increased creatinine clearance and increased renal drug clearance. Unless these effects are offset by ensuing renal and/or hepatic impairment, with subsequent drug accumulation, antibiotic levels may be too low for optimal efficacy. The institution of continuous renal replacement therapy separately affects antibiotic clearances, and therefore dosing, even further.

This article reviews relevant literature and offers principles for more effective and appropriate antibiotic dosing in the critically ill, based on the pharmacokinetic and pharmacodynamic principles of the main antibiotic groups (aminoglyosides, glycopeptides, β-lactams, carbapenems and quinolones) and knowledge of the pathophysiology of the inflammatory response syndrome. Finally it also provides some guidance on the basic principles of drug prescription for patients receiving continuous renal replacement therapy.
Tenoxicam 20 mg or 40 mg after Thoracotomy: A Prospective, Randomized, Double-blind, Placebo-controlled Study
Authors: Merry A. F. , Sidebotham D. A. , Middleton N. G. , Calder M. V. , Webster C. S.
Published: January 2019

Forty-five adults undergoing thoracotomy were randomized to receive placebo, tenoxicam 20 mg or tenoxicam 40 mg IV during chest wall closure. All patients received intraoperative fentanyl and intercostal blocks followed by morphine by patient-controlled analgesia. Patient numbers 13 to 45 also received thoracic epidural analgesia by continuous infusion of bupivacaine 0.125%, patient numbers 25 to 45 having fentanyl 2 μg/ml added to the epidural infusion. Efficacy parameters and adverse reactions were assessed over the first 24 hours postoperatively. On a 100 mm visual analogue scale, mean (SD) pain at rest (adjusted area under curve for hours 1 to 24) was 25.8 (12.5), 17.4 (14.8) and 16.5 (13.3) mm for groups receiving placebo, 20 mg and 40 mg tenoxicam, respectively (ANOVA: P< 0.05). There were no significant differences between study groups postoperatively in pain on coughing, opioid consumption, blood gas measurements, nausea, vomiting, sedation, blood loss, haemoglobin or serum creatinine. One patient in each tenoxicam group reported epigastric pain, rated moderate. These data support the inclusion of tenoxicam 20 mg IV in the management of pain at rest for patients undergoing thoracotomy, but do not show additional benefit for a higher dose.