Patterns of knee osteoarthritis management in general practice: a retrospective cohort study using electronic health records

OBJECTIVE

This study determined patterns of knee osteoarthritis (OA) management by general practitioners (GPs) using routine healthcare data from Dutch general practices from 2011 to 2019.

DESIGN

A retrospective cohort study was conducted using the Integrated Primary Care Information database between 2011 and 2019. Electronic health records (EHRs) of n = 750 randomly selected knee OA patients (with either codified or narrative diagnosis) were reviewed against eligibility criteria and n = 503 patients were included. Recorded information was extracted on GPs' management from six months before to three years after diagnosis and patterns of management were analysed.

RESULTS

An X-ray referral was the most widely recorded management modality (63.2%). The next most widely recorded management modalities were a referral to secondary care (56.1%) and medication prescription or advice (48.3%). Records of recommendation of/referral to other primary care practitioners (e.g. physiotherapists) were found in only one third of the patients. Advice to lose weight was least common (1.2%). Records of medication prescriptions or recommendation of/referral to other primary care practitioners were found more frequently in patients with an X-ray referral compared to patients without, while records of secondary care referrals were found less frequently. Records of an X-ray referral were often found in narratively diagnosed knee OA patients before GPs recorded a code for knee OA in their EHR.

CONCLUSION

These findings emphasize the importance of better implementing non-surgical management of knee OA in general practice and on initiatives for reducing the overuse of X-rays for diagnosing knee OA in general practice.

Short-term and long-term increased mortality in elderly patients with burn injury: a national longitudinal cohort study

BACKGROUND

The population of elderly patients with burn injuries is growing. Insight into long-term mortality rates of elderly after burn injury and predictors affecting outcome is limited. This study aimed to provide this information.

METHODS

A multicentre observational retrospective cohort study was conducted in all three Dutch burn centres. Patients aged ≥65 years, admitted with burn injuries between 2009 and 2018, were included. Data were retrieved from electronic patient records and the Dutch Burn Repository R3. Mortality rates and standardized mortality ratios (SMRs) were calculated. Multivariable logistic regression was used to assess predictors for in-hospital mortality and mortality after discharge at 1 year and five-year. Survival analysis was used to assess predictors of five-year mortality.

RESULTS

In total, 682/771 admitted patients were discharged. One-year and five-year mortality rates were 8.1 and 23.4%. The SMRs were 1.9(95%CI 1.5-2.5) and 1.4(95%CI 1.2-1.6), respectively. The SMRs were highest in patients aged 75-80 years at 1 year (SMRs 2.7, 95%CI 1.82-3.87) and five-year in patients aged 65-74 years (SMRs 10.1, 95%CI 7.7-13.0). Independent predictors for mortality at 1 year after discharge were higher age (OR 1.1, 95%CI 1.0-1.1), severe comorbidity, (ASA-score ≥ 3) (OR 4.8, 95%CI 2.3-9.7), and a non-home discharge location (OR 2.0, 95%CI 1.1-3.8). The relative risk of dying up to five-year was increased by age (HR 1.1, 95%CI 1.0-1.1), severe comorbidity (HR 2.3, 95%CI 1.6-3.5), and non-home discharge location (HR 2.1, 95%CI 1.4-3.2).

CONCLUSION

Long-term mortality until five-year after burn injury was higher than the age and sex-matched general Dutch population, and predicted by higher age, severe comorbidity, and a non-home discharge destination. Next to pre-injury characteristics, potential long-lasting systemic consequences on biological mechanisms following burn injuries probably play a role in increased mortality. Decreased health status makes patients more prone to burn injuries, leading to early death.

Increased adherence to perioperative safety guidelines associated with improved patient safety outcomes: a stepped-wedge, cluster-randomised multicentre trial

BACKGROUND

National Dutch guidelines have been introduced to improve suboptimal perioperative care. A multifaceted implementation programme (IMPlementatie Richtlijnen Operatieve VEiligheid [IMPROVE]) has been developed to support hospitals in applying these guidelines. This study evaluated the effectiveness of IMPROVE on guideline adherence and the association between guideline adherence and patient safety.

METHODS

Nine hospitals participated in this unblinded, superiority, stepped-wedge, cluster RCT in patients with major noncardiac surgery (mortality risk ≥1%). IMPROVE consisted of educational activities, audit and feedback, reminders, organisational, team-directed, and patient-mediated activities. The primary outcome of the study was guideline adherence measured by nine patient safety indicators on the process (stop moments from the composite STOP bundle, and timely administration of antibiotics) and on the structure of perioperative care. Secondary safety outcomes included in-hospital complications, postoperative wound infections, mortality, length of hospital stay, and unplanned care.

RESULTS

Data were analysed for 1934 patients. The IMPROVE programme improved one stop moment: 'discharge from recovery room' (+16%; 95% confidence interval [CI], 9-23%). This stop moment was related to decreased mortality (-3%; 95% CI, -4% to -1%), fewer complications (-8%; 95% CI, -13% to -3%), and fewer unscheduled transfers to the ICU (-6%; 95% CI, -9% to -3%). IMPROVE negatively affected one other stop moment - 'discharge from the hospital' - possibly because of the limited resources of hospitals to improve all stop moments together.

CONCLUSIONS

Mixed implementation effects of IMPROVE were found. We found some positive associations between guideline adherence and patient safety (i.e. mortality, complications, and unscheduled transfers to the ICU) except for the timely administration of antibiotics.

CLINICAL TRIAL REGISTRATION

NTR3568 (Dutch Trial Registry).

Complexity and involvement as implementation challenges: results from a process analysis

Background

The study objective was to analyse the implementation challenges experienced in carrying out the IMPROVE programme. This programme was designed to implement checklist-related improvement initiatives based on the national perioperative guidelines using a stepped-wedge trial design. A process analysis was carried out to investigate the involvement in the implementation activities.

Methods

An involvement rating measure was developed to express the extent to which the implementation programme was carried out in the hospitals. This measure reflects the number of IMPROVE-implementation activities executed and the estimated participation in these activities in all nine participating hospitals. These data were compared with prospectively collected field notes.

Results

Considerable variation between the hospitals was found with involvement ratings ranging from 0 to 6 (mean per measurement = 1.83 on a scale of 0–11). Major implementation challenges were respectively the study design (fixed design, time planning, long duration, repeated measurements, and data availability); the selection process of hospitals, departments and key contact person(s) (inadequately covering the entire perioperative team and stand-alone surgeons); the implementation programme (programme size and scope, tailoring, multicentre, lack of mandate, co-interventions by the Inspectorate, local intervention initiatives, intervention fatigue); and competitive events such as hospital mergers or the introduction of new IT systems, all reducing involvement.

Conclusions

The process analysis approach helped to explain the limited and delayed execution of the IMPROVE-implementation programme. This turned out to be very heterogeneous between hospitals, with variation in the number and content of implementation activities carried out. The identified implementation challenges reflect a high complexity with regard to the implementation programme, study design and setting. The involvement of the target professionals was put under pressure by many factors. We mostly encountered challenges, but at the same time we provide solutions for addressing them. A less complex implementation programme, a less fixed study design, a better thought-out selection of contact persons, as well as more commitment of the hospital management and surgeons would likely have contributed to better implementation results.

Trial registration

Dutch Trial Registry: NTR3568, retrospectively registered on 2 August 2012.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12913-021-07090-z.

Reducing work pressure and IT problems and facilitating IT integration and audit & feedback help adherence to perioperative safety guidelines: a survey among 95 perioperative professionals

Background

To improve perioperative patient safety, guidelines for the preoperative, peroperative, and postoperative phase were introduced in the Netherlands between 2010 and 2013. To help the implementation of these guidelines, we aimed to get a better understanding of the barriers and drivers of perioperative guideline adherence and to explore what can be learned for future implementation projects in complex organizations.

Methods

We developed a questionnaire survey based on the theoretical framework of Van Sluisveld et al. for classifying barriers and facilitators. The questionnaire contained 57 statements derived from (a) an instrument for measuring determinants of innovations by the Dutch Organization for Applied Scientific Research, (b) interviews with quality and safety policy officers and perioperative professionals, and (c) a publication of Cabana et al. The target group consisted of 232 perioperative professionals in nine hospitals. In addition to rating the statements on a five-point Likert scale (which were classified into the seven categories of the framework: factors relating to the intervention, society, implementation, organization, professional, patients, and social factors), respondents were invited to rank their three most important barriers in a separate, extra open-ended question.

Results

Ninety-five professionals (41%) completed the questionnaire. Fifteen statements (26%) were considered to be barriers, relating to social factors (N = 5), the organization (N = 4), the professional (N = 4), the patient (N = 1), and the intervention (N = 1). An integrated information system was considered an important facilitator (70.4%) as well as audit and feedback (41.8%). The Barriers Top-3 question resulted in 75 different barriers in nearly all categories. The most frequently reported barriers were as follows: time pressure (16% of the total number of barriers), emergency patients (8%), inefficient IT structure (4%), and workload (3%).

Conclusions

We identified a wide range of barriers that are believed to hinder the use of the perioperative safety guidelines, while an integrated information system and local data collection and feedback will also be necessary to engage perioperative teams. These barriers need to be locally prioritized and addressed by tailored implementation strategies. These results may also be of relevance for guideline implementation in general in complex organizations.

Trial registration

Dutch Trial Registry: NTR3568.

Development and validation of a Self-assessment Instrument for Perioperative Patient Safety (SIPPS)

Background

Patient safety is a fundamental value of healthcare to avoid patient harm. Non‐compliance with patient safety standards may result in patient harm and is therefore a global concern. A Self‐assessment Instrument for Perioperative Patient Safety (SIPPS) monitoring and benchmarking compliance to safety standards was validated in a multicentre pilot study.

Methods

A preliminary questionnaire, based on the Dutch perioperative patient safety guidelines and covering international patient safety goals, was evaluated in a first digital RAND Delphi round. The results were used to optimize the questionnaire and design the SIPPS. For measurement and benchmarking purposes, SIPPS was categorized into seven main patient safety domains concerning all care episode phases of the perioperative trajectory. After consensus was reached in a face‐to‐face Delphi round, SIPPS was pilot‐tested in five hospitals for five characteristics: measurability, applicability, improvement potential, discriminatory capacity and feasibility.

Results

The results of the first Delphi round showed moderate feasibility for the preliminary questionnaire (81·6 per cent). The pilot test showed good measurability for SIPPS: 99·8 per cent of requested information was assessable. Some 99·9 per cent of SIPPS questions were applicable to the selected respondents. With SIPPS, room for improvement in perioperative patient safety compliance was demonstrated for all hospitals, concerning all safety domains and all care episode phases of the perioperative trajectory (compliance 76·1 per cent). SIPPS showed mixed results for discriminatory capacity. SIPPS showed good feasibility for all items (range 91·9–95·7 per cent).

Conclusion

A self‐assessment instrument for measuring perioperative patient safety (SIPPS) compliance meeting international standards was validated. With SIPPS, improvement areas for perioperative patient safety and best practices across hospitals could be identified.

Development of the Surgical Patient safety Observation Tool (SPOT)

Background

A Surgical Patient safety Observation Tool (SPOT) was developed and tested in a multicentre observational pilot study. The tool enables monitoring and benchmarking perioperative safety performance across departments and hospitals, covering international patient safety goals.

Methods

Nineteen perioperative patient safety observation topics were selected from Dutch perioperative patient safety guidelines, which also cover international patient safety goals. All items that measured these selected topics were then extracted from available local observation checklists of the participating hospitals. Experts individually prioritized the best measurement items per topic in an initial written Delphi round. The second (face to face) Delphi round resulted in consensus on the content of SPOT, after which the measurable elements (MEs) per topic were defined. Finally, the tool was piloted in eight hospitals for measurability, applicability, improvement potential, discriminatory capacity and feasibility.

Results

The pilot test showed good measurability for all 19 patient safety topics (range of 8-291 MEs among topics), with good applicability (median 97 (range 11·8-100) per cent). The overall improvement potential appeared to be good (median 89 (range 72·5-100) per cent), and at topic level the tool showed good discriminatory capacity (variation 27·5 per cent, range in compliance 72·5-100 per cent). Overall scores showed relatively little variation between the participating hospitals (variation 13 per cent, range in compliance 83-96 per cent). All eight auditors considered SPOT a straightforward and easy-to-use tracer tool.

Conclusion

A comprehensive tool to measure safety of care was developed and validated using a systematic, stepwise method, enabling hospitals to monitor, benchmark and improve perioperative safety performance.

Defining hip pain trajectories in early symptomatic hip osteoarthritis--5 year results from a nationwide prospective cohort study (CHECK)

OBJECTIVE

To define distinct hip pain trajectories in individuals with early symptomatic hip osteoarthritis (OA) and to determine risk factors for these pain trajectories.

METHOD

Data were obtained from the nationwide prospective Cohort Hip and Cohort Knee (CHECK) study. Participants with hip pain or stiffness and a completed 5-year follow-up were included. Baseline demographic, anamnestic, physical examination characteristics were assessed. Outcome was annually assessed by the Numeric Rating Scale (NRS) for pain. Pain trajectories were retrieved by latent class growth analysis (LCGA). Multinomial logistic regression was used to calculate risk ratios.

RESULTS

545 participants were included. Four distinct pain trajectories were uncovered by LCGA. We found significant differences in baseline characteristics, including body mass index (BMI); symptom severity; pain coping strategies and in criteria for clinical hip OA (American College of Rheumatology (ACR)). Lower education, higher activity limitation scores, frequent use of pain transformation as coping strategy and painful internal hip rotation were more often associated with trajectories characterized by more severe pain. No association was found for baseline radiographic features.

CONCLUSION

We defined four distinct pain trajectories over 5 years follow-up in individuals with early symptomatic hip OA, suggesting there are differences in symptomatic progression of hip OA. Baseline radiographic severity was not associated with the pain trajectories. Future research should be aimed at measuring symptomatic progression of hip OA with even more frequent symptom assessment.

[Pain trajectories in early symptomatic knee osteoarthritis]

DESIGN

Retrospective cohort study.

METHOD

We obtained data for this study from the 'Cohort Hip and Cohort Knee' (CHECK) study. Participants who presented with knee osteoarthritis at baseline were included. We assessed baseline patient parameters such as demographics, anamnesis and physical examination measurements. Pain outcome measure was assessed annually using a numeric rating scale. Different pain trajectories were defined by latent class growth analysis. Multinomial logistic regression was used to calculate relative risk ratios.

RESULTS

In total, 705 participants were included. Six distinct pain trajectories were identified with favourable and unfavourable courses. We found significant differences in baseline characteristics between the different pain trajectories, including BMI; symptom severity; and pain coping strategies. Higher BMI, lower education, presence of co-morbidities, higher activity limitation scores and joint space tenderness were more often associated with trajectories characterized by more pain at first presentation and pain progression. No association was found for baseline radiographic features.

CONCLUSION

We defined six distinct pain trajectories in individuals with early symptomatic knee osteoarthritis. Our results can help physicians identify those patients that require more frequent monitoring compared patients for whom a watch-and-wait policy seems justifiable. In general practice, radiography does not provide added value to the follow-up of early symptomatic knee osteoarthritis patients.

Alcohol-related emergency department admissions among adolescents in the Ghent and Sint-Niklaas areas

Alcohol abuse is a major health concern. The aim of this retrospective study was to analyse the alcohol-related emergency department (ED) admissions among adolescents in all hospitals of distinct areas during a 1-year period. In each hospital, all ED patients with a blood alcohol concentration (BAC) of at least 0.5 g/l were surveyed in a standardised way. Of the 3918 included patients, only 146 (3.7%) were < 18  years. The male-to-female ratio was 1.5:1. There was a strong preponderance of weekend and night time admissions. Most of the patients were transported by ambulance (77% of 138 patients with information on this item). The main reason for ED admittance was depressed level of consciousness (64%), trauma (12%), vomiting and/or abdominal pain (12%), agitation or aggression (4%), syncope (4%) and psychological problems (4%). The context of the alcohol intoxication was related to some kind of festivity in 85%, mental problems in 14% and chronic abuse in 1%. Median BAC values (and range) were 2.08 g/l (0.73-3.70 g/l) for boys and 1.51 g/l (0.73-2.90 g/l) for girls. Most patients (87%) could be discharged home within 24  hours. Our study confirms that problematic alcohol use leading to ED admissions starts in adolescence. Although the numbers of cases below 18 years are low when compared to adults, the phenomenon is alarming as it is associated with substantial health problems. Therefore, Belgium urgently needs a global national alcohol plan, with youngsters being one of the target groups.

Improving the implementation of perioperative safety guidelines using a multifaceted intervention approach: protocol of the IMPROVE study, a stepped wedge cluster randomized trial

BACKGROUND

This study is initiated to evaluate the effects, costs, and feasibility at the hospital and patient level of an evidence-based strategy to improve the use of Dutch perioperative safety guidelines. Based on current knowledge, expert opinions and expertise of the project team, a multifaceted implementation strategy has been developed.

METHODS/DESIGN

This is a stepped wedge cluster randomized trial including nine representative hospitals across The Netherlands. Hospitals are stratified into three groups according to hospital type and geographical location and randomized in terms of the period for receipt of the intervention. All adult surgical patients meeting the inclusion criteria are assessed for patient outcomes. The implementation strategy includes education, audit and feedback, organizational interventions (e.g., local embedding of the guidelines), team-directed interventions (e.g., multi-professional team training), reminders, as well as patient-mediated interventions (e.g., patient safety cards). To tailor the implementation activities, we developed a questionnaire to identify barriers for effective guideline adherence, based on (a) a theoretical framework for classifying barriers and facilitators, (b) an instrument for measuring determinants of innovations, and (c) 19 semi-structured interviews with perioperative key professionals. Primary outcome is guideline adherence measured at the hospital (i.e., cluster) and patient levels by a set of perioperative Patient Safety Indicators (PSIs), which was developed parallel to the perioperative guidelines. Secondary outcomes at the patient level are in-hospital complications, postoperative wound infections and mortality, length of hospital stay, and unscheduled transfer to the intensive care unit, non-elective readmission to the hospital and unplanned reoperation, all within 30 days after the initial surgery. Also, patient safety culture and team climate will be studied as potential determinants. Finally, a process evaluation is conducted to identify the compliance with the implementation strategy, as well as an economic evaluation to assess the costs. Data sources are registered clinical data and surveys. There is no form of blinding.

DISCUSSION

The perioperative setting is an unexplored area with respect to implementation issues. This study is expected to yield important new evidence about the effects of a multifaceted approach on guideline adherence in the perioperative care setting.

TRIAL REGISTRATION

Dutch trial registry: NTR3568.

The impact of a standardized incident reporting system in the perioperative setting: a single center experience on 2,563 'near-misses' and adverse events

Background

The reduction of perioperative harm is a major priority of in-hospital health care and the reporting of incidents and their causes is an important source of information to improve perioperative patient safety. We explored the number, nature and causes of voluntarily reported perioperative incidents in order to highlight the areas where further efforts are required to improve patient safety.

Methods

Data from the Hospital Incident Management System (HIMS), entered in the period from July 2009 to July 2012, were analyzed in a Dutch university hospital. Employees in the perioperatve field filled out a semi-structured digital form of the reporting system. The risk classification of the reported adverse events and ‘near misses’ was based on the estimated patient consequences and the risk of recurrence, according to national guidelines. Predefined reported incident causes were categorized as human, organizational, technical and patient related.

Results

In total, 2,563 incidents (1,300 adverse events and 1,263 ‘near-miss’ events) were reported during 67,360 operations. Reporters were anesthesia, operating room and recovery nurses (37%), ward nurses (31%), physicians (17%), administrative personnel (5%), others (6%) and unmentioned (3%). A total of 414 (16%) adverse events had patient consequences (which affected 0,6% of all surgery patients), estimated as catastrophic in 2, very serious in 34, serious in 105, and marginally serious in 273 cases. Shortcomings in communication was the most frequent reported type of incidents. Non-compliance with Standard Operating Procedures (SOPs: instructions, regulations, protocols and guidelines) was reported with 877 (34%) of incident reports. In total, 1,194 (27%) voluntarily reported causes were SOP-related, mainly human-based (79%) and partially organization-based (21%). SOP-related incidents were not associated with more patient consequences than other voluntarily reported incidents. Furthermore ‘mistake or forgotten’ (15%) and ‘communication problems’ (11%) were frequently reported causes of incidents.

Conclusions

The analysis of voluntarily reported perioperative incidents identified an association between perioperative patient safety problems and human failure, such as SOP non-compliance, mistakes, forgetting, and shortcomings in communication. The data suggest that professionals themselves indicate that SOP compliance in combination with other human failures provide room for improvement.

Meta-analysis of operative mortality and complications in patients from minority ethnic groups

BACKGROUND

Insight into the effects of ethnic disparities on patients' perioperative safety is necessary for the development of tailored improvement strategies. The aim of this study was to review the literature on safety differences between patients from minority ethnic groups and those from the ethnic majority undergoing surgery.

METHODS

PubMed, CINAHL, the Cochrane Library and Embase were searched using predefined inclusion criteria for available studies from January 1990 to January 2013. After quality assessment, the study data were organized on the basis of outcome, statistical significance and the direction of the observed effects. Relative risks for mortality were calculated.

RESULTS

After screening 3105 studies, 26 studies were identified. Nine of these 26 studies showed statistically significant higher mortality rates for patients from minority ethnic groups. Meta-analysis demonstrated a greater risk of mortality for these patients compared with patients from the Caucasian majority in studies performed both in North America (risk ratio 1·22, 95 per cent confidence interval 1·05 to 1·42) and outside (risk ratio 2·25, 1·40 to 3·62). For patients from minority groups, the length of hospital or intensive care unit stay was significantly longer in five studies, and complication rates were significantly higher in ten. Methods used to identify patient ethnicity were not described in 14 studies.

CONCLUSION

Patients from minority ethnic groups, in North America and elsewhere, have an increased risk of perioperative death and complications. More insight is needed into the causes of ethnic disparities to pursue safer perioperative care for patients of minority ethnicity.

Inter-observer reliability for radiographic assessment of early osteoarthritis features: the CHECK (cohort hip and cohort knee) study

OBJECTIVE

To calculate inter-observer reliability between four different trained readers and an experienced reader on early radiographic osteoarthritis (OA) features in our early OA cohort hip and cohort knee (CHECK) cohort.

METHODS

Four readers were trained by a radiologist and experienced reader to score radiographic OA features. After this training they scored the CHECK cohort. Of the 1002 participants, 38 were scored by all readers. Five different angle radiographs (three for the knee, two for the hip) at three different time points were scored and compared. Inter-observer reliability was evaluated between each of the four trained readers and the experienced reader. Separate radiographic OA features and of overall Kellgren & Lawrence (K&L) scores. In addition, reliability of progression of radiographic was determined in K&L scores and joint space narrowing (JSN).

RESULTS

For hip and knee there was substantial inter-observer reliability on overall K&L scores. In the knee, JSN was scored with fair to moderate reliability, osteophytes with moderate to nearly perfect reliability, and other features with fair to substantial reliability. In the hip, reliability ranged from substantial to nearly perfect. Moderate inter-observer reliability was found for progression of OA in both knee and hip, with slightly better reliability for progression based on K&L scores than on separate features.

CONCLUSION

Good inter-observer reliability can be achieved between trained readers and an experienced reader. Although JSN in the knee is scored with lower inter-observer reliability than osteophytes, this does not seem to influence overall K&L scoring. In the hip all features showed good reliability.

Skin pentosidine in very early hip/knee osteoarthritis (CHECK) is not a strong independent predictor of radiographic progression over 5 years follow-up

OBJECTIVES

Age-related changes in articular cartilage are likely to play a role in the etiology of osteoarthritis (OA). One of the major age-related changes in cartilage is the accumulation of advanced glycation end products (AGEs). The present study evaluates whether pentosidine can predict radiographic progression and/or burden over 5 years follow-up in a cohort of early knee and/or hip OA.

DESIGN

The 5 years follow-up data of 300 patients from cohort hip & cohort knee (CHECK) were used. Radiographic progression and burden were assessed by X-rays of both knees and hips (Kellgren and Lawrence (K&L) and Altman scores). Baseline pentosidine levels (and urinary CTXII as a comparator) were measured by high-performance-liquid-chromatography (HPLC) and enzyme linked immunosorbent assay (ELISA). Univariable and multivariable associations including baseline radiographic damage, age, gender, body mass index (BMI) and kidney function were performed.

RESULTS

Both pentosidine and urinary C-terminal telopeptide of type II collagen (uCTXII) correlated with radiographic progression and burden. In general pentosidine did not have an added predictive value to uCTXII for progression nor burden of the disease. The best prediction was obtained for burden of radiographic damage (R(2) = 0.60-0.88), bus this was predominantly determined by baseline radiographic damage (without this parameter R(2) = 0.07-0.17). Interestingly, pentosidine significantly added to prediction of osteophyte formation, whereas uCTXII significantly added to prediction of JSN in multivariable analysis.

CONCLUSION

Pentosidine adds to prediction of radiographic progression and burden of osteophyte formation and uCTXII to radiographic progression and burden of JSN, but overall skin pentosidine did not perform better that uCTXII in predicting radiographic progression or burden. Burden of damage over 5 years is mainly determined by radiographic joint damage at baseline.

[Fire by spontaneous combustion of oxygen cylinders]

The use of medicinal oxygen can be dangerous. The spontaneous combustion of an oxygen cylinder was the cause of a fire in an operating theatre and an emergency medical service. The fire developed after turning on the gas main while the flow supply valve was already open. Not opening the pressure reduction valve while the oxygen flow supply valve is open can prevent this type of fire. Information from the contractor shows that the probability of such an incident is 1 in a million.

[The national Dutch Institute for Healthcare Improvement guidelines 'Preoperative trajectory': the essentials]

In view of the shortcomings of the organisation of the perioperative process that have been ascertained by the Dutch Health Inspectorate (IGZ), the Inspectorate has requested hospitals and care professionals to implement measures to improve this situation. In response to the IGZ's first report, the Dutch Institute for Healthcare Improvement (CBO) has developed the national, multiprofessional guidelines entitled 'Preoperative Trajectory' which were published in January 2010. Implementation of these guidelines should improve communication between professionals and lead to standardization and transparency of the preoperative patient care process, with uniform handovers and clear responsibilities. These guidelines are the first to provide recommendations at process of care level which are intended to increase patient safety and reduce the risk of damage to patients.

[Prevention of perioperative cardiac complications in non-cardiac surgery: an evidence-based guideline]

Approximately 2.5% of the patients undergoing non-cardiac surgery suffer from perioperative cardiac complications. These are associated with a mortality of 20.60%, a longer stay in hospital and higher costs. The risk factors for perioperative cardiac complications are: high-risk surgery, ischaemic heart disease, a history of congestive heart failure, cerebrovascular disease, diabetes, and renal failure. Recently, the scope of medical management has shifted from assessing and treating underlying culprit coronary lesions toward coronary plaque stabilisation and prevention of myocardial oxygen supply demand mismatch. Currently, the prevention of cardiac problems consists of identification of the patients at risk, optimisation of the preoperatieve condition by modification of underlying risk factors, optimisation of the perioperative medication with adrenergic beta-antagonists, statins, and acetylsalicylic acid, adequate perioperative monitoring and measures to prevent myocardial ischaemia. These include adequate sedation and analgesia, adequate oxygenation, oxygen transport, and ventilation, and if necessary additional cardiac medication.

Toxicity testing using hematopoietic stem cell assays

For over 40 years, in vitro assays have been used to understand the complex system of hematopoiesis. Now, several of these assays are undergoing resurgence as scientists in academia and industry are discovering how these assays can be utilized in drug discovery and development. These assays use primary cells from various hematopoietic tissues in multiple species to provide high content information. While conditions in the human body cannot be completely reproduced in vitro, hematopoietic colony-forming cell assays are proving to be a clinically relevant tool to evaluate potential toxic effects of new compounds. The ability to use these assays as a replacement of, or in conjunction with, high-throughput screening assays and high priced in vivo assays can improve the success of the decision-making process, saving time and costs during drug development.

A survey on alcohol and illicit drug abuse among emergency department patients

Alcohol and illicit drug abuse are major health care problems frequently leading to emergency department admission. The aims of this survey were (1) to determine for the Ghent University Hospital how frequently substance abuse contributed to emergency department admissions, (2) to describe the most important clinical features of these patients and (3) to determine how frequently these patients were referred to appropriate psychiatric services. All 1,941 patients attending the emergency department during the month of September 2003 were registered by the attending emergency department personnel. After exclusion of 8 cases, 1,933 patients were included: 198 (10%) with substance abuse leading to the emergency department admission (= INTOX group) and 1,735 (90%) in the NON-INTOX group. Males and the 21-50 years age group were overrepresented in the INTOX group. Patients with substance abuse were also overrepresented during the night, but not during the weekend. Among the patients from the INTOX group the most frequent reason for the emergency department visit was a psychiatric problem (102/198; 51%). Traumatic lesions related to a fight (n= 19), to a traffic accident (n= 17) and to leisure time activities (n=30) were also frequent. In most patients, only alcohol was abused (144/198; 73%), most frequently chronically (102/144; 71%). In 13% (26/198), there was only illicit drug use, and in 14% (28/198) alcohol abuse was combined with illicit drug use. Among the 54 patients with illicit drug use (with or without alcohol abuse) the most frequently reported drugs were cannabis (54%), cocaine (41%), amphetamines (39%) and opiates (39%). With regard to referral to appropriate psychosocial services it was striking that 53% (19/36) of trauma patients with chronic substance abuse were not offered that type of help. We conclude that abuse of alcohol--and to a much lesser degree illicit drugs--is a frequent cause of emergency department admissions. Our data may help to convince and/or reinforce health care policy makers, emergency department medical directors and the public that alcohol consumption (much more than illicit drugs) is responsible for avoidable morbidity and mortality, and that well-co-ordinated strategies against unhealthy alcohol use are urgently needed. In this respect, the importance of detection and referral of emergency department patients with unhealthy alcohol use should be stressed.

[Prophylactic perioperative beta-blockade reduces cardiac morbidity and mortality following non-cardiac surgery in patients at risk]

Approximately 5% of all patients undergoing non-cardiac surgery suffer some form of perioperative cardiac morbidity, usually preceded by myocardial ischaemia. In the Netherlands, the cardiac mortality following non-cardiac surgery is 0.68%. The patient groups at risk for cardiac complications are: age 65 years and older, patients with coronary artery disease or risk factors for coronary artery disease, and those undergoing major surgery. The period of greatest risk is the early postoperative phase. Prophylactic beta-blockade significantly reduces perioperative cardiac morbidity and mortality: the odds ratio for myocardial ischaemia is 0.34 (95% CI: 0.23-0.52), for non-fatal myocardial infarction 0.15 (95% CI: 0.06-0.40) and for cardiac mortality 0.25 (95% CI: 0.09-0.73). Long-term continuation of the beta-blockade also reduces cardiac morbidity and mortality in the first two years following the operation.

[Admission and discharge criteria for intensive care departments]

Admission and discharge criteria for intensive care departments have been drawn up in order to optimise the use of scarce and costly intensive care facilities. Every patient who could benefit from admission must be assessed by the intensive care specialist beforehand. Admission is indicated for patients with disrupted vital functions in whom recovery of dysfunctioning or failing organ systems is expected, patients who will act as organ donors and patients who undergo diagnostic investigations associated with a high risk of vital complications. Frequent assessment (several times per day) of the 'indication to stay' is indicated in the case of many patients in order to maximise the admission capacity. Discharge from the intensive care department is indicated if the vital functions are stable without life support and no longer require monitoring or treatment, if nursing the patient in the ward is possible, if continuation of the medical treatment is no longer worthwhile, if the patient no longer consents to the treatment and if the benefit of a treatment no longer outweights its negative effects.

BCR-ABL accelerates C2-ceramide-induced apoptosis

In patients with chronic myeloid leukemia (CML), the neoplastic (BCR-ABL+) progenitor cells are characterized by an increased proliferative activity. Whether these cells are also resistant to apoptosis and if so, under what conditions remains controversial. We now show that highly purified populations of very primitive neoplastic progenitor cells obtained directly from CML patients survive and proliferate in vitro for several weeks in the absence of any added growth factors (except insulin). In contrast, purified primary normal progenitors maintained under the same conditions die rapidly. Nevertheless, both primary CML cells and BCR-ABL+ BAF3 cells show the same dose-dependent sensitivity to TNF-alpha or ceramide-induced apoptosis as their respective normal counterparts. In fact, time course studies demonstrated an even faster onset of apoptosis in ceramide-treated BCR-ABL+ BAF3 cells as compared to normal controls. BCR-ABL+ cells treated with ceramide also showed a rapid and sequential increase in the tyrosine phosphorylation of p210(BCR-ABL), p46-56SHC and p120Cbl. These findings suggest growth factor deprivation and treatment with TNF-alpha or ceramide trigger different initial events both of which can lead to apoptosis in factor-dependent hematopoietic cells. However, in the first case, activation of apoptosis is blocked by the basal activity of p210(BCR-ABL), whereas in the second, the presence of p210(BCR-ABL) appears to accelerate the onset of apoptosis by a mechanism that may involve an activation of its kinase function.

Reduction of reperfusion injury of human myocardium by allopurinol: a clinical study

To determine the possibility of myocardial protection against reperfusion injury by allopurinol, 22 aortocoronary bypass patients were studied. Eight patients received allopurinol (200 mg during induction of anesthesia and 100 mg after starting extracorporeal circulation) during surgery (group B), and 14 patients served as a control (group A). Blood samples and myocardial biopsies were taken before and 10 min after aortic cross-clamping. No statistically significant difference between the two groups was observed considering gender, age, prior myocardial infarction, left ventricular end diastolic pressure (LVEDP), and aortic cross-clamp time. Preservation of cardiac tissue was assessed by the measurement of quantitative birefringence (QBR) changes upon the addition of adenosine 5'-triphosphate (ATP) plus calcium in biopsies and the need for postoperative inotropes. The synthesis of peroxides was estimated by the measurement of leukotriene B4 and C4 (LTB4, LTC4). LTB4 was below the level of detection (< 1.5 ng/l) before and after cross-clamping in both groups, while the LTC4 level for group A increased from < 1.5 to 27 +/- 17 ng/l compared to an increase of < 1.5 to 11 +/- 8 ng/l for group B after 10 min of reperfusion (p = .036). The decrease in QBR value in group A was 1.26 +/- 0.28 and 0.35 +/- 0.23 for group B (p < .003). Postoperatively, 11 out of 14 patients in group A needed inotropic support (dopamine or dobutamine), whereas two patients out of eight did so in group B.(ABSTRACT TRUNCATED AT 250 WORDS)

Disconnection of the ventilatory system does not prevent pleural lesions during sternotomy

In previous studies pleurotomy has seldom been reported as a complication of sternotomy and, therefore, the incidence is unknown. Factors increasing or decreasing the risk of pleurotomy also have not been studied properly. In a prospective, randomized trial, performed during 14 consecutive months from 1988 until 1989, the incidence of pleurotomy and its possible risk factors were studied in 712 patients undergoing median sternotomy for cardiac and mediastinal procedures. The overall incidence of pleurotomy was 14.7%. Chronic obstructive pulmonary disease, the use of positive end-expiratory pressure, and continuation or discontinuation of the ventilatory system did not affect the incidence. A surgeon-related risk factor could be significantly identified (P < 0.001). In conclusion, disconnection of the ventilatory system during sternotomy has been shown to have no influence on the pleurotomy rate and its continued use is no longer valid.

Erythropoietin-induced tyrosine phosphorylations in a high erythropoietin receptor-expressing lymphoid cell line

Retroviral gene transfer of the murine erythropoietin receptor (EpR) cDNA into the pro-B-cell line, Ba/F3, was used to generate cells expressing high EpR levels. One of the resulting clones, Ba/F3 clone C5, contained 5 integrated copies of the gene and expressed, at the cell surface, a single affinity class of EpRs at 10 to 15 times the level present on spleen cells from phenylhydrazine-treated mice. Cross-linking studies with clone C5, using 125I-Ep, yielded the same two 105- and 88-Kd major species as that seen with typical erythroid cells. This was distinct from that obtained with EpR-transfected COS cells or L cells, which gave species of 88 and 65 Kd. This suggests that the biologically active EpR complex generated in this Ba/F3 cell line may closely resemble that present in native Ep-responsive erythroid progenitor cells. Tyrosine phosphorylation experiments showed that several proteins in clone C5 cells were rapidly phosphorylated on tyrosine residues in response to Ep, one being the EpR itself. The proportion of cell surface EpRs tyrosine phosphorylated in response to Ep was substantial, reaching a maximum of approximately 10% within 30 minutes of incubation at 37 degrees C. A comparison of Ep- and murine interleukin-3 (mIL-3)-induced tyrosine phosphorylation patterns in clone C5 cells showed that both growth factors stimulated the tyrosine phosphorylation of proteins with molecular weights of 135, 93, 70, and 55 Kd. This could suggest that the Ep and mIL-3 receptors are capable of using the same tyrosine kinase in these cells.

Acute hemodynamic effects of pericardial closure in man

The acute hemodynamic effects of pericardial closure were studied in 30 patients with normal left ventricular function, who were undergoing coronary artery bypass surgery. Closure of the pericardium resulted in decreases in arterial blood pressure (P less than 0.01), cardiac index (P less than 0.001), mean right atrial (P less than 0.001), mean pulmonary artery (P less than 0.001) and pulmonary capillary wedge pressure (P less than 0.001). The observed hemodynamic changes are probably caused by a change in the ventricular pressure-volume relationships.

Effect of dietary lipids on plasma lipoproteins and fluidity of lymphoid cell membranes in normal and leukemic mice

Mice of the GR/A strain were fed four different isocaloric semipurified diets, enriched in either (1) saturated fatty acids (palm oil), or (2) polyunsaturated fatty acids (corn oil), or (3) palm oil plus cholesterol, or (4) a fat-poor diet containing only a minimal amount of essential fatty acids. We have studied the effects of these dietary lipids on the density profile and composition of the plasma lipoproteins and on the lipid composition and fluidity of (purified) lymphoid cell membranes in healthy mice and in mice bearing a transplanted lymphoid leukemia (GRSL). Tumor development in these mice occurred in the spleen and in ascites. While the fatty acid composition of the VLDL-triacylglycerols still strongly resembled the dietary lipids, the effects of the diets decreased in the order VLDL-triacylglycerols greater than HDL-phospholipids greater than plasma membrane phospholipids. Diet-induced differences in the latter fraction were virtually confined to the content of oleic acid and linoleic acid, and they were too small to affect the membrane fluidity, as measured by fluorescence polarization using the probe 1,6-diphenyl-1,3,5-hexatriene. Healthy mice were almost irresponsive to dietary cholesterol, but in the tumor bearers, where lipoprotein metabolism has been shown to be disturbed, the cholesterol diet caused a substantial increase in the low- and very-low density regions of both blood and ascites plasma lipoproteins. The cholesterol-rich diet also increased the cholesterol/phospholipid molar ratio and lipid structural order (decreased fluidity) in GRSL ascites cell membranes, but not in the splenic GRSL cell membranes. We conclude that the composition of plasma lipoproteins and cell membrane lipids in GR/A mice is subject to exquisite homeostatic control. However, in these low-responders to dietary lipids the development of an ascites tumor may lead to increased responsiveness to dietary cholesterol. The elevated level of membrane cholesterol thus obtained in GRSL ascites cells did not affect the expression of various cell surface antigens or tumor cell growth.

Positive tip cultures and related risk factors associated with intravascular catheterization in pediatric cardiac patients

The incidence and risk factors of positive catheter tip cultures were studied prospectively in 392 consecutive children undergoing cardiac surgery under cover of cephalothin prophylaxis. A total of 1649 catheter tips were cultured and 58 (3.5%) yielded positive cultures. Specifically, the incidence of positive catheter tip cultures for iv, central venous, arterial and pulmonary arterial (PA) catheters was 0.9%, 5.9%, 3.9% and 10.6%, respectively, whereas one of the six surgically placed venous and arterial catheters had a positive tip culture and none of the 279 transthoracic catheters. Staphylococcus epidermidis was isolated from 79% of the positive tip cultures. Ten percent of the children had one or more positive tip cultures but none developed catheter-related septicemia or endocarditis. Stepwise logistic regression analysis revealed that longer in situ time (p less than .001), younger age (p less than .001), and inotropic support (p = .003) were significant independent predictors of risk for children developing positive catheter tip cultures. The safe in situ period for arterial, central venous, and PA catheters is 3 days in infants under 1 yr and 4 and 6 days for arterial and central venous catheters, respectively, in older children, if 0.95 cumulative probability of remaining free of a positive tip culture is accepted. The data generally support the bacteriologic safety of invasive hemodynamic monitoring in infants and children undergoing cardiac surgery.

The microbiologic risk of invasive haemodynamic monitoring in open-heart patients requiring prolonged ICU treatment

The microbiologic risk of invasive haemodynamic monitoring and support was prospectively studied in 48 patients undergoing open-heart surgery under antibiotic prophylaxis and requiring intensive care for longer than 4 days. A total of 420 catheter tips were cultured of which 12 (2.9%) were positive. The incidence of positive catheter tip cultures was as follows: intravenous 1.8%, central venous 1.2%, arterial 1.8%, pulmonary arterial 5.9%, direct right atrial 2.4%, direct left atrial 0% and intra-aortic balloon pump catheters 7.7%. The rate of positive tip cultures was not significantly different for percutaneously and surgically inserted catheters (3.1% and 1.7% respectively). One (0.2%) catheter was associated with bacteraemia. Although the overall positive catheter tip culture rate was low, 21% of the patients had one or more positive catheter tip cultures. Complicated surgical procedures, a cardiopulmonary bypass time longer than 3.5 h, mechanical ventilation for more than 7 days, intensive care stay longer than 10 days, positive blood cultures and the use of more than 20 catheters were all individually associated with a significantly higher incidence of patients with positive tip cultures. Nevertheless, no patient developed endocarditis nor major morbidity related to the positive catheter tip cultures. Invasive haemodynamic monitoring does not seem to be an important microbiologic risk in open-heart patients requiring intensive care for longer than 4 days.

Infectious complications of simultaneously inserted central venous and pulmonary artery catheters

Infectious complications associated with simultaneously inserted pulmonary artery and central venous catheters via the same internal jugular vein were studied prospectively in 622 patients undergoing open-heart surgery under cephalothin prophylaxis. Successful insertion of the catheters was achieved in 650 (98.3%) of 661 attempts, while puncture complications occurred in 51 (8.2%) patients. One (0.2%) patient developed a local infection and 24 (3.9%) patients had one or more positive catheter-tip cultures without complications related to the positive cultures. Patients with puncture complications had no significantly different incidence of positive tip cultures. The incidence of positive catheter-tip cultures for pulmonary artery and central venous catheters was 2.6% and 1.7% respectively. Monitoring with a pulmonary artery and central venous catheter inserted via the same internal jugular vein is associated with a low rate of infectious complications.

The use of balloon-tipped pulmonary artery catheters in children undergoing cardiac surgery

Percutaneous pulmonary artery (PA) catheterization via the internal jugular vein was studied in 58 children undergoing cardiac surgery. Central venous cannulation, which succeeded in all children, was associated with a 10% incidence of inadvertent carotid artery puncture without untoward effects. Successful placement of the PA catheter was achieved in 47 (92%) of the 51 children in whom it was anatomically possible to enter the pulmonary artery at the time of the catheterization. Four (8%) catheter tip cultures were positive. The PA catheter yielded important information in diagnosing low cardiac output, severe pulmonary hypertension or residual cardiac defects in 27 (47%) children. Twenty (35%) children had critical therapeutic interventions because of the PA catheter information. The high yield of important data and the low incidence of major complications seem to justify the use of percutaneously inserted PA catheters in children with an increased operative risk.

A prospective analysis of 1,400 pulmonary artery catheterizations in patients undergoing cardiac surgery

During 1983 and 1984, 1305 patients underwent 1,400 pulmonary artery (PA) catheterizations. Successful placement was achieved in 1397 (99.6%) of 1,403 attempts. The catheters were inserted via the right internal jugular vein on 1364 occasions. The median duration of monitoring was 28 h with a range from 3 to 220 h. Central venous puncture complications included carotid artery puncture in 67 instances (4.8%) and pneumothorax in one patient. Insertion of the catheters was associated with supraventricular arrhythmias on 11 occasions, ventricular arrhythmias on 930 (66.4%), right bundle branch block on two and a total heart block on one occasion. Eighteen (2.3%) of the 794 cultured catheter tips were positive. An in situ time of more than 72 h was associated with a significantly higher percentage (7.2%) of positive tip cultures compared with an in situ time of less than 72 h (P less than 0.01). Repeated PA catheterization was not associated with significantly more complications than the initial catheterization. The results show that monitoring with a PA catheter in cardiac surgical patients is associated with a low incidence of morbidity.

The microbiological risk of invasive hemodynamic monitoring in adults undergoing cardiac valve replacement

The microbiological risk of invasive hemodynamic monitoring was studied prospectively in 230 consecutive patients undergoing cardiac valve replacement during prophylactic therapy with cephalothin. A total of 923 catheter tips were cultured, and 1.6% yielded positive cultures. The rate of positive cultures did not differ significantly between catheters inserted percutaneously (1.9% positive) and those inserted surgically (0.5% positive). The incidence of positive catheter tip cultures for intravenous, central venous, arterial, and pulmonary arterial catheters was 0, 1.5, 2.6, and 2.9%, respectively, whereas the surgically inserted right and left atrial catheters yielded 0.6 and 0% positive tip cultures, respectively. One patient developed septicemia related to a right atrial catheter. There was no correlation between the incidence of positive catheter tip cultures and the length of time that the catheters remained in situ. No patient developed early or late endocarditis. Invasive hemodynamic monitoring seems to be microbiologically safe, even in patients undergoing cardiac valve replacement.

Ventricular arrhythmias during insertion and removal of pulmonary artery catheters

The incidence and significance of the development of ventricular arrhythmias during insertion and removal of pulmonary artery monitoring catheters were determined in stable postcardiac surgical patients. Insertion of 173 (69 percent) of 250 catheters was associated with ventricular arrhythmias and removal in 158 (63 percent) of these catheters (p greater than 0.05). All arrhythmias resolved spontaneously. Patients who underwent valve replacement showed significantly fewer arrhythmias during withdrawal than those who underwent a coronary artery bypass operation (p less than 0.025). Factors significantly influencing the incidence of ventricular arrhythmias during removal were increased postoperative CK-MB levels (p less than 0.025) and cardiac index (p less than 0.025).

Microbiologic risk of invasive hemodynamic monitoring in patients undergoing open-heart operations

The microbiologic risk of invasive hemodynamic monitoring was studied prospectively in 574 patients undergoing open-heart surgery under cover of cephalothin prophylaxis. Of a total of 2277 catheters inserted in these patients, 1.5% yielded positive cultures. The rate of positive cultures was not significantly different between percutaneous and surgically placed catheters (1.7% vs. 0.8%, respectively). Specifically, the incidence of positive catheter tips for intravenous, central venous, arterial, and pulmonary artery catheters was 1.1%, 3.9%, 1.5%, and 2.1%, respectively; while the corresponding rates for surgically inserted right atrial and left atrial catheters were 0.8% and 0, respectively. Pulmonary artery catheters had a significantly (p less than .01) higher incidence of positive catheter tips after 72 h in situ. However, there was no relationship between the in situ time and the incidence of positive tips for arterial and intravenous catheters. Although the rate of positive catheter tip cultures was low, it affected 4.9% of the patients. Nevertheless, no patient developed catheter-related septicemia or endocarditis, and the data generally supported the microbiologic safety of invasive hemodynamic monitoring in patients undergoing open-heart surgery.

Alterations in biosynthesis and homeostasis of cholesterol and in lipoprotein patterns in mice bearing a transplanted lymphoid tumor

The membrane fluidity of murine lymphoid GRSL tumor cells has been shown to depend on their site of growth in the host. Tumor cells located in ascites, in contrast to those in the enlarged spleen, show a very high plasma membrane fluidity, mainly due to a decreased level of cellular (membrane) cholesterol. Yet, the rate of cholesterol biosynthesis in the tumor cells as estimated by the activity of HMG-CoA reductase and the incorporation of [14C]acetate into cholesterol was extremely high when compared to various lymphoid cells in normal control mice. Also the rate of biosynthesis and the cholesterol content in liver and spleen of tumor-bearing mice were substantially higher than in the organs of control mice. Blood plasma cholesterol, however, was decreased in tumor-bearing mice as a result of altered lipoprotein patterns. Outgrowth of the tumor was accompanied by a strong reduction in plasma high-density lipoproteins. Low-density lipoproteins became transiently increased, but eventually all lipoproteins, and consequently the plasma cholesterol content decreased to very low levels, especially so in the ascites plasma. The low transfer of [14C]cholesteryl ester-labeled lipoproteins between blood and ascites plasma after either intravenous or intraperitoneal injection suggested a hampered flow between the two compartments. Also apparent differences in cholesteryl ester fatty acid composition between lipoproteins of the blood and ascites plasma indicated the lack of a rapid equilibration between the two compartments. The results suggest that the limited availability of lipoproteins as an additional source of cholesterol to the rapidly growing ascites cells promotes their high membrane fluidity.

The effect of high-dose fentanyl anaesthesia on P50 in man

The effect of high dosage fentanyl anaesthesia on P50 was studied in patients undergoing coronary bypass surgery. After induction of fentanyl anaesthesia 100 micrograms X kg-1 with pancuronium muscle relaxation P50 changed significantly (P less than 0.005) from 3.40 +/- 0.12 to 3.33 +/- 0.13 kPa. This anaesthesia technique decreases P50 in vivo, but this has more theoretical than practical importance.