Evaluation of the Paediatric Index of Mortality in children managed on adult intensive care units

Objective: To evaluate the performance of the Paediatric Index of Mortality (PIM) in children cared for in adult intensive care units (ICUs) in district general hospitals in the South West Region of England. Design and setting: An observational survey of all children admitted to adult ICUs in 15 district general hospitals between November 2000 and August 2002. For comparison, data were also collected from the regional paediatric ICUs between November 2000 and March 2002. Results: Data were collected from 374 children admitted to adult ICUs and 850 children admitted to the regional paediatric ICU. There were significant differences in the patient characteristics between the two groups. In the adult ICU paediatric population, PIM discriminated well between death and survival (Az ROC = 0.96 (95% confidence interval, 0.93 to 0.99)) and calibrated well across deciles of risk (goodness of fit χ² = 4.55 (8 df), p = 0.8). Conclusions: PIM performs well as a risk adjustment method in children whose entire care remains in the adult ICU of a district general hospital. This is important should the Paediatric Intensive Care Audit Network (PICAnet) decide to extend its data collection beyond paediatric intensive care units to other units caring for critically ill children.     

Risk adjusted mortality of critical illness in a defined geographical region.

AIMS: To evaluate the performance of the Paediatric Risk of Mortality (PRISM) score in a population of UK children and to use this score to examine severity of illness adjusted mortality of critically ill children <16 years old in a defined geographical region. METHODS: Observational study of a defined population of critically ill children (<16 years old) admitted to hospitals in the South West Region between 1 December 1996 and 30 November 1998. RESULTS: Data were collected from 1148 eligible admissions. PRISM was found to perform acceptably in this population. There was no significant difference between the overall number of observed deaths and those predicted by PRISM. Admissions with mortality risk 30% or greater had significantly greater odds ratio for death in general intensive care units compared with the tertiary paediatric intensive care unit. CONCLUSIONS: Children with a high initial risk of mortality based on PRISM score were significantly more likely to survive in a tertiary paediatric intensive care unit than in general intensive care units in this region. However, there was no evidence from this study that admissions with lower mortality risk than 30% had significantly worse mortality in non-tertiary general units than in tertiary paediatric intensive care units.     

Risk adjusted mortality of critical illness in a defined geographical region

Aims: To evaluate the performance of the Paediatric Risk of Mortality (PRISM) score in a population of UK children and to use this score to examine severity of illness adjusted mortality of critically ill children <16 years old in a defined geographical region. Methods: Observational study of a defined population of critically ill children (<16 years old) admitted to hospitals in the South West Region between 1 December 1996 and 30 November 1998. Results: Data were collected from 1148 eligible admissions. PRISM was found to perform acceptably in this population. There was no significant difference between the overall number of observed deaths and those predicted by PRISM. Admissions with mortality risk 30% or greater had significantly greater odds ratio for death in general intensive care units compared with the tertiary paediatric intensive care unit. Conclusions: Children with a high initial risk of mortality based on PRISM score were significantly more likely to survive in a tertiary paediatric intensive care unit than in general intensive care units in this region. However, there was no evidence from this study that admissions with lower mortality risk than 30% had significantly worse mortality in non-tertiary general units than in tertiary paediatric intensive care units.     

A comparison of three scoring systems for mortality risk among retrieved intensive care patients

Aims: To assess the impact of two paediatric intensive care unit retrieval teams on the performance of three mortality risk scoring systems: pre-ICU PRISM, PIM, and PRISM II. Methods: A total of 928 critically ill children retrieved for intensive care from district general hospitals in the south east of England (crude mortality 7.8%) were studied. Results: Risk stratification was similar between the two retrieval teams for scores utilising data primarily prior to ICU admission (pre-ICU PRISM, PIM), despite differences in case mix. The fewer variables required for calculation of PIM resulted in complete data collection in 88% of patients, compared to pre-ICU PRISM (24%) and PRISM II (60%). Overall, all scoring systems discriminated well between survival and non-survival (area under receiver operating characteristic curve 0.83–0.87), with no differences between the two hospitals. There was a tendency towards better discrimination in all scores for children compared to infants and neonates, and a poor discrimination for respiratory disease using pre-ICU PRISM and PRISM II but not PIM. All showed suboptimal calibration, primarily as a consequence of mortality over prediction among the medium (10–30%) mortality risk bands. Conclusions: PIM appears to offer advantages over the other two scores in terms of being less affected by the retrieval process and easier to collect. Recalibration of all scoring systems is needed.     

A comparison of three scoring systems for mortality risk among retrieved intensive care patients.

AIMS: To assess the impact of two paediatric intensive care unit retrieval teams on the performance of three mortality risk scoring systems: pre-ICU PRISM, PIM, and PRISM II. METHODS: A total of 928 critically ill children retrieved for intensive care from district general hospitals in the south east of England (crude mortality 7.8%) were studied. RESULTS: Risk stratification was similar between the two retrieval teams for scores utilising data primarily prior to ICU admission (pre-ICU PRISM, PIM), despite differences in case mix. The fewer variables required for calculation of PIM resulted in complete data collection in 88% of patients, compared to pre-ICU PRISM (24%) and PRISM II (60%). Overall, all scoring systems discriminated well between survival and non-survival (area under receiver operating characteristic curve 0.83-0.87), with no differences between the two hospitals. There was a tendency towards better discrimination in all scores for children compared to infants and neonates, and a poor discrimination for respiratory disease using pre-ICU PRISM and PRISM II but not PIM. All showed suboptimal calibration, primarily as a consequence of mortality over prediction among the medium (10-30%) mortality risk bands. CONCLUSIONS: PIM appears to offer advantages over the other two scores in terms of being less affected by the retrieval process and easier to collect. Recalibration of all scoring systems is needed.     

The state of paediatric intensive care retrieval in Britain

Paediatric intensive care (PIC) services have been centralised to a significant extent in Britain in the past two decades. As part of centralisation, PIC retrieval teams were developed to transport critically ill children from district general hospitals to regional paediatric intensive care units. This review aims to summarise the current state of retrieval in Britain, with reference to the past and possible directions for the future. While significant progress has been achieved, and PIC retrieval has now become a clinical service in its own right, the coming years present unique opportunities as well as challenges for the specialty.     

Correlation between severity of disease and reimbursement of costs in neonatal and paediatric intensive care patients

Abstract Aim: The aim of the present study was to investigate the correlation between neonatal, paediatric and adult disease severity scores and reimbursement by health insurances. Methods: The setting was a university hospital's neonatal intensive care unit (NICU) and paediatric intensive care unit (PICU). We performed a prospective study of all patients admitted over the 3-month study period. Data collected included five scoring systems to predict mortality or to quantify disease severity (Paediatric Index of Mortality [PIM], Paediatric Risk of Mortality [PRISM], Simplified Acute Physiological Score [SAPS], Score for Neonatal Acute Physiology [SNAP], Therapeutic Intervention Scoring System [TISS]) on a daily basis, the total reimbursement as calculated by the grouper according to the German diagnosis-related groups (DRG) system, age of the patient, length of stay (LOS), International Classification of Diseases (ICD)-10 and DRG diagnosis. Our intention was to determine the correlation between different neonatal, paediatric and adult scores (PIM, PRISM III, SAPS-II, SNAP, Core-10-TISS), and reimbursement by the health insurance on the basis of the German DRG system in its 2005 and 2007 version. Results: No positive correlation between any score applied and reimbursement by the health insurance could be identified. Reimbursement was positively correlated to the length of hospital stay. Positive correlations could also be shown for some of the scores among each other. Conclusion: We conclude that other scoring systems or measures of disease severity urgently need to be established to terminate the chronic underfunding of paediatric intensive care medicine in the developed countries.     

Calibration of the paediatric index of mortality in UK paediatric intensive care units.

AIM: To test a paediatric intensive care mortality prediction model for UK use. METHOD: Prospective collection of data from consecutive admissions to five UK paediatric intensive care units (PICUs), representing a broad cross section of paediatric intensive care activity. A total of 7253 admissions were analysed using tests of the discrimination and calibration of the logistic regression equation. RESULTS: The model discriminated and calibrated well. The area under the ROC plot was 0.84 (95% CI 0.819 to 0.853). The standardised mortality ratio was 0.87 (95% CI 0.81 to 0.94). There was remarkable concordance in the performance of the paediatric index of mortality (PIM) within each PICU, and in the performance of the PICUs as assessed by PIM. Variation in the proportion of admissions that were ventilated or transported from another hospital did not affect the results. CONCLUSION: We recommend that UK PICUs use PIM for their routine audit needs. PIM is not affected by the standard of therapy after admission to PICU, the information needed to calculate PIM is easy to collect, and the model is free.     

Quantifying high dependency care: a prospective cohort study in Yorkshire (UK)

High dependency care (HDC) is a level of care situated between intensive care and usual ward care with its delivery being independent of location. Inadequate definition makes it problematic to determine the number of children receiving HDC, to identify their care setting and therefore to undertake service planning. We aimed to estimate the volume of hospital inpatient HDC in a geographically defined population using a customised measurement tool in four types of paediatric hospital services (1) tertiary specialist wards, (2) tertiary paediatric intensive care units, (3) district general hospitals (DGHs) general wards and (4) wards at a major acute general hospital. A region-wide prospective cohort study during 2005 collected data to develop a 36-item HDC measurement tool, which then identified children receiving HDC by day and night. The cohort identified 1,763 children as receiving HDC during an admission to 1 of 36 hospital wards in 14 hospitals. HDC was delivered during 9,077 shift periods of 12 h or 4,538 bed days. The volume of care and patient profiles varied by hospital type, within hospital by ward type and by age and season. Tertiary specialist wards and ICUs provided 72% of HDC, with the remainder delivered at the DGHs and the major acute general hospital. The volume of admissions to tertiary specialist wards showed little seasonality and children tended to be older (26% were aged 10–15 years). By comparison, admissions to DGHs were younger with an excess during the winter months. This is the first UK study to quantify HDC from empirical data encompassing all hospital and ward types within a large clinical network. A lack of HDC-designated beds across the region resulted in HDC delivery on all types of hospital wards. The study size and representativeness makes the estimated number of HDC bed days per head of population likely to reflect the wider UK population.     

Reliability of PRISM and PIM scores in paediatric intensive care

Aims: To assess the reliability of mortality risk assessment using the Paediatric Risk of Mortality (PRISM) score and the Paediatric Index of Mortality (PIM) in daily practice. Methods: Twenty seven physicians from eight tertiary paediatric intensive care units (PICUs) were asked to assess the severity of illness of 10 representative patients using the PRISM and PIM scores. Physicians were divided into three levels of experience: intensivists (>3 years PICU experience, n = 12), PICU fellows (6–30 months of PICU experience, n = 6), and residents (<6 months PICU experience, n = 9). This represents all large PICUs and about half of the paediatric intensivists and PICU fellows working in the Netherlands. Results: Individual scores and predicted mortality risks for each patient varied widely. For PRISM scores the average intraclass correlation (ICC) was 0.51 (range 0.32–0.78), and the average kappa score 0.6 (range 0.28–0.87). For PIM scores the average ICC was 0.18 (range 0.08–0.46) and the average kappa score 0.53 (range 0.32–0.88). This variability occurred in both experienced and inexperienced physicians. The percentage of exact agreement ranged from 30% to 82% for PRISM scores and from 28 to 84% for PIM scores. Conclusion: In daily practice severity of illness scoring using the PRISM and PIM risk adjustment systems is associated with wide variability. These differences could not be explained by the physician''s level of experience. Reliable assessment of PRISM and PIM scores requires rigorous specific training and strict adherence to guidelines. Consequently, assessment should probably be performed by a limited number of well trained professionals.     

Reliability of PRISM and PIM scores in paediatric intensive care.

AIMS: To assess the reliability of mortality risk assessment using the Paediatric Risk of Mortality (PRISM) score and the Paediatric Index of Mortality (PIM) in daily practice. METHODS: Twenty seven physicians from eight tertiary paediatric intensive care units (PICUs) were asked to assess the severity of illness of 10 representative patients using the PRISM and PIM scores. Physicians were divided into three levels of experience: intensivists (>3 years PICU experience, n = 12), PICU fellows (6-30 months of PICU experience, n = 6), and residents (<6 months PICU experience, n = 9). This represents all large PICUs and about half of the paediatric intensivists and PICU fellows working in the Netherlands. RESULTS: Individual scores and predicted mortality risks for each patient varied widely. For PRISM scores the average intraclass correlation (ICC) was 0.51 (range 0.32-0.78), and the average kappa score 0.6 (range 0.28-0.87). For PIM scores the average ICC was 0.18 (range 0.08-0.46) and the average kappa score 0.53 (range 0.32-0.88). This variability occurred in both experienced and inexperienced physicians. The percentage of exact agreement ranged from 30% to 82% for PRISM scores and from 28 to 84% for PIM scores. CONCLUSION: In daily practice severity of illness scoring using the PRISM and PIM risk adjustment systems is associated with wide variability. These differences could not be explained by the physician's level of experience. Reliable assessment of PRISM and PIM scores requires rigorous specific training and strict adherence to guidelines. Consequently, assessment should probably be performed by a limited number of well trained professionals.     

The burden of paediatric intensive care: an Australian and New Zealand perspective

Most seriously ill children in Australia and New Zealand are cared for in specialised intensive care units associated with tertiary children's hospitals. Highly regionalised models of care are in operation. Children from remote areas are transported to intensive care by paediatric emergency transport services. Indigenous children have disease and injury patterns similar to parts of the developing world and are over-represented in the intensive care population. The outcome for children admitted to intensive care compares favourably with international benchmarks. There is also evidence of uniformity of outcomes across paediatric intensive care units in the region and that outcomes have been improving. Although there are some downward pressures on intensive care workloads (preventative strategies such as immunisation, safety campaigns), these are counterbalanced by new surgical initiatives and increasing expectations of extended high tech support for children with life shortening diseases and disabilities. This expanding group of technology-dependent children will be one of the major challenges facing health authorities and intensive care physicians in this region in the coming decade.     

Epidemiology of traumatic brain injury in children receiving intensive care in the UK.

AIMS: To describe the epidemiology of children with traumatic brain injury (TBI) admitted to paediatric intensive care units (PICUs) in the UK. METHODS: Prospective collection of clinical and demographic information from paediatric and adult intensive care units in the UK and Eire between February 2001 and August 2003. RESULTS: The UK prevalence rate for children (0-14 years) admitted to intensive care with TBI between February 2001 and August 2003 was 5.6 per 100,000 population per year (95% Poisson exact confidence intervals 5.17 to 6.05). Children admitted to PICUs with TBI were more deprived than the population as a whole (mean Townsend score for TBI admissions 1.19 v 0). The commonest mechanism of injury was a pedestrian accident (36%), most often occurring in children over 10. There was a significant summer peak in admissions in children under 10 years. Time of injury peaked in the late afternoon and early evening, a pattern that remained constant across the days of the week. Injuries involving motor vehicles have the highest mortality rates (23% of vehicle occupants, 12% of pedestrians) compared with cyclists (8%) and falls (3%). In two thirds of admissions (65%) TBI was an isolated injury. CONCLUSIONS: TBI in children requiring intensive care is more common in those from poorer backgrounds who have been involved in accidents as pedestrians. The summer peak in injury occurrence for 0-10 year olds and late afternoon timing give clear targets for community based injury prevention.     

Protecting children from iatrogenic harm during COVID19 pandemic

Critical care management of patients with COVID‐19 has been influenced by a mixture of public, media and societal pressure, as well as clinical and anecdotal observations from many prominent researchers and key opinion leaders. These factors may have affected the principles of evidence‐based medicine and encouraged the widespread use of non‐tested pharmacological and aggressive respiratory support therapies, even in intensive care units (ICUs). The COVID‐19 pandemic has predominantly affected adult populations, while children appear to be relatively spared of severe disease. Notwithstanding, paediatric intensive care (PICU) clinicians may already have been influenced by changes in practices of adult ICUs, and these changes may pose unintended consequences to the vulnerable population in the PICU. In this article, we analyse several potential iatrogenic causes of the detrimental effects of the current pandemic to children and highlight the risks underlying a sudden change of clinical practice.     

Epidemiology of traumatic brain injury in children receiving intensive care in the UK

Aims: To describe the epidemiology of children with traumatic brain injury (TBI) admitted to paediatric intensive care units (PICUs) in the UK. Methods: Prospective collection of clinical and demographic information from paediatric and adult intensive care units in the UK and Eire between February 2001 and August 2003. Results: The UK prevalence rate for children (0–14 years) admitted to intensive care with TBI between February 2001 and August 2003 was 5.6 per 100 000 population per year (95% Poisson exact confidence intervals 5.17 to 6.05). Children admitted to PICUs with TBI were more deprived than the population as a whole (mean Townsend score for TBI admissions 1.19 v 0). The commonest mechanism of injury was a pedestrian accident (36%), most often occurring in children over 10. There was a significant summer peak in admissions in children under 10 years. Time of injury peaked in the late afternoon and early evening, a pattern that remained constant across the days of the week. Injuries involving motor vehicles have the highest mortality rates (23% of vehicle occupants, 12% of pedestrians) compared with cyclists (8%) and falls (3%). In two thirds of admissions (65%) TBI was an isolated injury. Conclusions: TBI in children requiring intensive care is more common in those from poorer backgrounds who have been involved in accidents as pedestrians. The summer peak in injury occurrence for 0–10 year olds and late afternoon timing give clear targets for community based injury prevention.     

No resuscitation orders and withdrawal of therapy in French paediatric intensive care units

Objective: To determine the incidence of different modes of death in French paediatric intensive care units and to compare patients' characteristics, including a severity of illness score (Paediatric Risk of Mortality: PRISM score) and prior health status (Paediatric Overall Performance Category scale), according to the mode of death. Design: A 4-month prospective cohort study. Setting: Nine French multidisciplinary paediatric intensive care units. Patients: All patients who died in PICUs, except premature babies. Main results: Among 712 admissions, 13% patients died. Brain death was declared in 20%, failure of cardiopulmonary resuscitation occurred in 26%, do-not-resuscitate status was identified in 27%, and withdrawal of supportive therapy was noted in 27%. The PRISM score and the baseline Paediatric Overall Performance Category were not different between the four groups. Brain-dead patients were older than those in whom a do-not-resuscitate order and withdrawal of therapy were made (median age 81 vs 7 and 4 months). Conclusions: Decisions to limit or to withdraw supportive care were made for a majority of patients dying in French paediatric intensive care units. Chronic health evaluation and severity of illness index are not sufficient to describe dead-patient populations.     

Paediatric use of intensive care

OBJECTIVES--To determine the number of children from a defined population who use intensive care facilities, to analyse bed occupancy data for those children, and to estimate the number of intensive care beds required to satisfy this demand throughout the year. DESIGN--Examination of admission data books from intensive care units within the four Birmingham health authorities and the neighbouring health authorities. RESULTS--Two hundred and ninety seven children resident within the four Birmingham health authorities used intensive care facilities in a calendar year. One hundred and forty one (47%) of these were admitted for specialist paediatric services. Of the remaining 156, 106 (68%) were cared for in adult intensive care units, 46 (29%) in a paediatric intensive care unit and four (3%) in a special care baby unit. Use of intensive care varied from none to 11 patients each day, and was lowest in the summer and highest during the winter months. During periods of peak demand, one in 19,000 (5.3/100,000) children were using intensive care facilities. CONCLUSIONS--These data provide a population based minimum need for paediatric intensive care beds. They are higher than previous estimates and do not include provision for children from outside Birmingham, or for those denied intensive care due to bed shortages. These factors and the marked seasonal variation in demand need to be considered when planning intensive care services for children if bed shortages are to be avoided.     

Paediatric use of intensive care.

OBJECTIVES--To determine the number of children from a defined population who use intensive care facilities, to analyse bed occupancy data for those children, and to estimate the number of intensive care beds required to satisfy this demand throughout the year. DESIGN--Examination of admission data books from intensive care units within the four Birmingham health authorities and the neighbouring health authorities. RESULTS--Two hundred and ninety seven children resident within the four Birmingham health authorities used intensive care facilities in a calendar year. One hundred and forty one (47%) of these were admitted for specialist paediatric services. Of the remaining 156, 106 (68%) were cared for in adult intensive care units, 46 (29%) in a paediatric intensive care unit and four (3%) in a special care baby unit. Use of intensive care varied from none to 11 patients each day, and was lowest in the summer and highest during the winter months. During periods of peak demand, one in 19,000 (5.3/100,000) children were using intensive care facilities. CONCLUSIONS--These data provide a population based minimum need for paediatric intensive care beds. They are higher than previous estimates and do not include provision for children from outside Birmingham, or for those denied intensive care due to bed shortages. These factors and the marked seasonal variation in demand need to be considered when planning intensive care services for children if bed shortages are to be avoided.     

The Comparison of PRISM and PIM scoring systems for mortality risk in infantile intensive care

Scoring systems that predict the risk of mortality for children in an intensive care unit (ICU) are needed for the evaluation of the effectiveness of pediatric intensive care. The Pediatric Risk of Mortality (PRISM) and the Pediatric Index of Mortality (PIM) scores have been developed to predict mortality among children in the ICU. The purpose of this study was to evaluate whether these systems are effective and population-independent. PRISM and PIM scores were calculated prospectively during a 1-year period solely on 105 non-surgical infants admitted to the ICU. Statistical analysis was performed to assess the performance of the scoring systems. There were 29 (27.6 per cent) deaths and 76 (72.4 per cent) survivors. SMR and Z scores for PIM and PRISM signified higher mortality and poor performance. Prediction of mortality by the scoring systems appeared to be underestimated in almost all risk groups. The Hosmer and Lemeshow test showed a satisfactory overall calibration of both scoring systems. Although ROC analysis showed a poor discriminatory function of both scores, a marginally acceptable performance for PIM was observed. The ROC curve also showed an acceptable performance for PIM, for patients with pre-existent chronic disorder. Although care must be taken not to overstate the importance of our results, we believe that when revised according to the characteristics of the population, PIM may perform well in predicting the mortality risk for infants in the ICU, especially in countries where the mortality rate is relatively high and pre-existent chronic disorders are more common.     

Where should paediatric surgery be performed?

We have tried to review the evidence for the organisation of paediatric surgical care. Difficulties arise because of the lack of published data from district general hospitals concerning paediatric surgical conditions. Hence much of the debate about the surgical management of children is based on anecdotal evidence. However, at a time when the provision of health care is being radically reorganised to an internal market based on a system of purchasers and providers it is more important than ever to understand the issues at stake. Two separate issues have been discussed: the role of the specialist paediatric centre and the provision of non-specialist paediatric surgery in district general hospitals. There are arguments for and against large regional specialist paediatric centres. The benefits of centralisation include concentration of expertise, more appropriate consultant on call commitment, development of support services, and junior doctor training. The disadvantages include children and their families having to travel long distances for care, and the loss of expertise at a local level. If specialist paediatric emergency transport is available the benefits of centralisation far outweigh the adverse effects of having to take children to a regional paediatric intensive care centre. Specialist paediatric centres are aware of the importance of treating children and their parents as a family unit as highlighted by the Platt committee; this is an important challenge and enormous improvements have occurred to provide proper accommodation for families while their children are treated in hospital. To keep these arguments of large distances and separation from the home in context, one paediatric intensive care unit in Victoria, Australia, providing a centralised service to a region larger in are than England and with a similar admission rate, has a lower mortality rate than the decentralised paediatric intensive care provided in the Trent region of the UK. There is clear evidence that all neonatal surgery and anaesthesia should be conducted only by specialists. The debate now centres around the number of complex surgical cases a unit should treat to maintain its specialist status. The NHS executive, in its guidelines on contracting for specialist services, emphasises that "Sensible contracting needs to take into account the optimum population size not only for the stability of contracted referrals but also to give sufficient 'critical mass' for clinical effectiveness." Achieving this balance has consequences, not just for the maintenance of surgical expertise, but for the essential ancilliary services. There is clear evidence in anaesthesia that anaesthetists doing small numbers of neonatal procedures had significantly worse results. The same seems to be true in the fields of oncology, radiology, pathology, and intensive care. The reasons why the results of management of certain paediatric conditions are better at specialist centres are open to speculation. Presumably greater exposure to rare complex cases, concentration of expertise, more peer review, and a trickle down effect of the multidisciplinary approach all help to keep health care workers up to date with current world practice. In addition, it allows for appropriate specialist on call rotas and dedicated junior staff. If insufficient numbers of specialist surgical cases are being treated at a centre then the whole multidisciplinary team suffers. The 1989 NCEPOD report states "that paediatricians and general surgeons must recognise that small babies differ from other patients not only in size, and that they pose quite separate problems of pathology and management." The need for large centres of paediatric surgical expertise is now accepted by the Royal College of Surgeons of England, the British Association of Paediatric Surgeons, the Senate of Surgery of Great Britain and Ireland, the Royal College of Paediatrics and Child Health, the Royal College of Anaesthetists, the Audit