Early postoperative emergencies requiring an intensive care team intervention. The role of ASA physical status and after-hours surgery

Rapid response team activation after major hip surgery: A case series

Introduction

We describe the demographic, preoperative, surgical, anesthetic, and postoperative characteristics of patients who required a rapid response team (RRT) activation after major hip surgery. We determined the characteristics and outcomes of patients that require RRTs after major hip surgery, and their associations with mortality.

Presentation of cases

We retrospectively reviewed adult patients undergoing major hip surgery in a university teaching hospital. We included patients who had an RRT or “code blue” activation post-surgery and within the index hospital admission. We extracted patient, surgical, anesthetic, and postoperative variables. We explored differences between patients who survived their index hospital stay and those who died.

Discussion

187 (9%) patients had a postoperative RRT activation. The median age was 84.0 (78–90) years; 125 (67%) were female, and most patients had significant comorbidities. The median Charlson Comorbidity Index (CCI) was 5.0 (4.0–7.0). Patients were frail (68%), ASA physical status ≥Class 3 (91%) and underwent emergency surgery (88%). Death after RRT activation occurred in 1 in 7 patients. Compared to patients who survived RRT activation, those who died had a higher mean CCI (6.5 [1.8] vs. 5.5 [2.1], P = 0.02), were more frail (80.1% vs. 56.5%, OR = 3.2, 95% CI: 1.2,8.1; P = 0.03), and received less intraoperative opioids (intravenous morphine equi-analgesia: median = 5.8 (0.1–8.20 vs. 11.7 (3.7–19.0) mg, P = 0.03).

Conclusion

Mortality after RRT activation is associated with non-modifiable patients factors rather than surgical or anesthesia factors. Our findings provide opportunities for the implementation of strategies aimed at improving postoperative outcomes.

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Major hip surgery poses a significant physiological challenge to patients.

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Almost one in ten patients had a postoperative rapid response team activation.

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Mortality rate was one in seven patients following rapid response team activation.

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Advanced age, frailty and emergency surgery were associated with RRT activation.

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Death post RRT activation was not associated with surgical or anesthesia factors.

Failure to detect ward hypoxaemia and hypotension: contributions of insufficient assessment frequency and patient arousal during nursing assessments

BACKGROUND

Postoperative hypotension and hypoxaemia are common and often unrecognised. With intermittent nursing vital signs, hypotensive or hypoxaemic episodes might be missed because they occur between scheduled measurements, or because the process of taking vital signs arouses patients and temporarily improves arterial blood pressure and ventilation. We therefore estimated the fraction of desaturation and hypotension episodes that did not overlap nursing assessments and would therefore usually be missed. We also evaluated the effect of taking vital signs on blood pressure and oxygen saturation.

METHODS

We estimated the fraction of desaturated episodes (arterial oxygen saturation <90% for at least 90% of the time within 30 continuous minutes) and hypotensive episodes (MAP <70 mm Hg for 15 continuous minutes) that did not overlap nursing assessments in patients recovering from noncardiac surgery. We also evaluated changes over time before and after nursing visits.

RESULTS

Among 782 patients, we identified 878 hypotensive episodes and 2893 desaturation episodes, of which 79% of the hypotensive episodes and 82% of the desaturation episodes did not occur within 10 min of a nursing assessment and would therefore usually be missed. Mean BP and oxygen saturation did not improve by clinically meaningful amounts during nursing vital sign assessments.

CONCLUSIONS

Hypotensive and desaturation episodes are mostly missed because vital sign assessments on surgical wards are sparse, rather than being falsely negative because the assessment process itself increases blood pressure and oxygen saturation. Continuous vital sign monitoring will detect more disturbances, potentially giving clinicians time to intervene before critical events occur.

Perioperative Medical Emergencies in a 23-Hour Surgical Procedure Unit

Purpose

Our 174-bed hospital operates a 23-hour/day procedure unit without a dedicated on-site high dependency unit or intensive care unit. The purpose of this investigation is to assess the incidence of medical emergency response (MER) and Code Blue (CB) events over 12 months.

Patients and Methods

A retrospective analysis of hospital records was conducted. Patients were identified using the medical emergency team (MET) database. Information pertaining to whether the patient was pre-operative, post-operative (including time and characteristics of the operation), or medical short stay overflow was obtained, in addition to the reason for the MER/CB event and outcome of the event.

Results

Of all hospital events, 8.45% (47 of 550) occurred in the perioperative ward. The incidence rate of events was 0.76% (95% CI: 0.53% to 0.99%) of all scheduled operations. The surgical procedure cancellation rate due to pre-operative MER/CB events was 0.11% (95% CI: 0.02% to 0.20%). Orthopedic surgery and ENT surgery were associated with the highest incidence of MER/CB events. Post-operative hypotension and reduced consciousness associated with vasovagal episodes were the most common clusters. The mean time after the operation for events to occur was 5.21 hours. 25.5% of events occurred outside of standard day surgery operating hours when there was limited access to onsite consultant anaesthetic or surgical staff (17:00 to 08:00).

Conclusion

This study highlights the anticipated medical emergencies for a 23-hour procedural unit and is of particular interest for evaluation by other short stay surgical, outpatient procedural, or rural hospital surgical units with limited after hours on-site critical care support.

Incidence, Severity, and Detection of Blood Pressure Perturbations after Abdominal Surgery

Editor’s Perspective

What We Already Know about This Topic

What This Article Tells Us That Is New

Background

Intraoperative and postoperative hypotension are associated with myocardial and kidney injury and 30-day mortality. Intraoperative blood pressure is measured frequently, but blood pressure on surgical wards is usually measured only every 4 to 6 h, leaving long intervals during which hypotension and hypertension may be undetected. This study evaluated the incidence and severity of postoperative hypotension and hypertension in adults recovering from abdominal surgery and the extent to which serious perturbations were missed by routine vital-sign assessments.

Methods

Blood pressure was recorded at 1-min intervals during the initial 48 h in adults recovering from abdominal surgery using a continuous noninvasive monitor. Caregivers were blinded to these measurements and depended on routine vital-sign assessments. Hypotension and hypertension were characterized as time under and above various mean arterial pressure thresholds.

Results

Of 502 available patients, 312 patients with high-quality records were analyzed, with a median measurement time of 48 [interquartile range: 41, 48] postoperative hours. Nearly a quarter experienced an episode of mean arterial pressure of less than 70 mm Hg lasting at least 30 min (24%; 95% CI, 20%, 29%), and 18% had an episode of mean arterial pressure of less than 65 mm Hg lasting at least 15 min. Nearly half the patients who had mean arterial pressure of less than 65 mm Hg for at least 15 min (47%; 95% CI, 34%, 61%) were undetected by routine vital-sign assessments. Episodes of mean arterial pressure greater than 110 mm Hg lasting at least 30 min were observed in 42% (95% CI, 37%, 48%) of patients; 7% had mean arterial pressure greater than 130 mm Hg for at least 30 min, 96% of which were missed by routine assessments. Episodes of mean arterial pressure less than 65 mm Hg and mean arterial pressure greater than 110 mm Hg captured by routine vital-sign assessments but not by continuous monitoring occurred in 34 and 8 patients, respectively.

Conclusions

Postoperative hypotension and hypertension were common, prolonged, profound, and largely undetected by routine vital-sign assessments in a cohort of adults recovering from abdominal surgery. Frequent or continuous blood pressure monitoring may detect hemodynamic perturbations more effectively and potentially facilitate treatment.

Safety of Deep Sedation in Patients Undergoing Full-Thickness Skin Graft Harvesting and Skin Graft Reconstruction for Limb Salvage An Outcome Analysis

BACKGROUND:

Studies on obtaining donor skin graft using intravenous sedation for patients undergoing major foot surgeries in the same operating room visit have not previously been reported. The objective of this retrospective study is to demonstrate that intravenous sedation in this setting is both adequate and safe in patients undergoing skin graft reconstruction of the lower extremities in which donor skin graft is harvested from the same patient in one operating room visit.

METHODS:

Medical records of 79 patients who underwent skin graft reconstruction of the lower extremities by one surgeon at the Yale New Haven Health System between November 1, 2008, and July 31, 2014, were reviewed. The patients' demographic characteristics, American Society of Anesthesiologists class, comorbid conditions, intraoperative analgesic administration, estimated blood loss, total operating room time, total postanesthesia care unit time, and postoperative complications within the first 72 hours were reviewed.

RESULTS:

This study found minimal blood loss and no postoperative complications, defined as any pulmonary or cardiac events, bleeding, admission to the intensive care unit, or requirement for invasive monitoring, in patients who underwent major foot surgery in conjunction with full-thickness skin graft.

CONCLUSIONS:

We propose that given the short duration and peripheral nature of the procedures, patients can safely undergo skin graft donor harvesting and skin graft reconstruction procedures with intravenous sedation regardless of American Society of Anesthesiologists class in one operating room visit.

Development of an Acute Care Plastic Surgery Service in the Saskatoon Health Region: Effects on flexor tendon management

BACKGROUND

The acute care surgery model has gained favour in general surgery, but has yet to be widely adopted in other specialties. An Acute Care Plastic Surgery (ACS) Service was recently implemented in the Saskatoon Health Region in an effort to improve trauma care.

OBJECTIVE

To evaluate the impact of ACS on the management of flexor tendon lacerations. The authors hypothesize that ACS has resulted in more timely intervention, improved outcomes and decreased 'after hours' surgery.

METHODS

A retrospective review of patients treated for flexor tendon lacerations from 2007 to 2013 was performed. Patients were stratified into two groups based on whether they received treatment before (group A) or after (group B) ACS implementation. Variables included dates and times of patient referral, consultation and tendon repair; postoperative complications; and admissions. A surgeon survey was administered on the perceived impact of ACS.

RESULTS

Group A was more likely to have surgery performed after hours (P=0.0019) and be admitted to hospital (P=0.0211) compared with group B. Time from referral to consultation and injury-to-surgery interval were slightly increased post-ACS (Group B). Surgeons were highly satisfied with the new system, citing benefits to patients and surgeons.

CONCLUSION

ACS was designed to improve trauma care, while favourably impacting surgeon workload. Surprisingly, the injury-to-surgery interval was slightly increased. However, this was not clinically significant and did not lead to increased postoperative complications. This finding was likely due to a favourable change in practice patterns observed after ACS implementation. ACS has resulted in fewer hospital admissions, decreased after-hours surgeries and improved surgeon satisfaction.

Development of an Acute Care Plastic Surgery Service in the Saskatoon Health Region: Effects on flexor tendon management

Background

The acute care surgery model has gained favour in general surgery, but has yet to be widely adopted in other specialties. An Acute Care Plastic Surgery (ACS) Service was recently implemented in the Saskatoon Health Region in an effort to improve trauma care.

Objective

To evaluate the impact of ACS on the management of flexor tendon lacerations. The authors hypothesize that ACS has resulted in more timely intervention, improved outcomes and decreased ‘after hours’ surgery.

Methods

A retrospective review of patients treated for flexor tendon lacerations from 2007 to 2013 was performed. Patients were stratified into two groups based on whether they received treatment before (group A) or after (group B) ACS implementation. Variables included dates and times of patient referral, consultation and tendon repair; postoperative complications; and admissions. A surgeon survey was administered on the perceived impact of ACS.

Results

Group A was more likely to have surgery performed after hours (P=0.0019) and be admitted to hospital (P=0.0211) compared with group B. Time from referral to consultation and injury-to-surgery interval were slightly increased post-ACS (Group B). Surgeons were highly satisfied with the new system, citing benefits to patients and surgeons.

Conclusion

ACS was designed to improve trauma care, while favourably impacting surgeon workload. Surprisingly, the injury-to-surgery interval was slightly increased. However, this was not clinically significant and did not lead to increased postoperative complications. This finding was likely due to a favourable change in practice patterns observed after ACS implementation. ACS has resulted in fewer hospital admissions, decreased after-hours surgeries and improved surgeon satisfaction.

Impact of an acute care surgery service on timeliness of care and surgeon satisfaction at a Canadian academic hospital: a retrospective study

Introduction

In January 2012 an acute care surgery (ACS) model was introduced at St. Paul’s Hospital, Saskatoon, Saskatchewan. The goal of implementing an ACS service was to improve the delivery of care for emergent, non-trauma surgical patients. We examined whether the ACS model improved wait time to surgery, decreased the proportion of surgeries performed after hours, and shortened post-surgical length of stay. We also assessed whether the surgeons working in an ACS system had higher on-call satisfaction than surgeons working in a non- ACS system.

Methods

A retrospective pre-post analysis was performed using data from the Discharge Abstract Database and the Organizing Medical Networked Information database. Surgeon satisfaction was evaluated using a questionnaire that was mailed to all general surgeons in Saskatoon.

Results

An ACS service significantly reduced wait time to surgery for patients with all acute general surgery diagnoses from 221 minutes to 192 minutes (ρ = 0.015; CI = 5.8-52.2). Post-surgery length of stay for patients operated on for acute appendicitis, or acute cholecystitis was not reduced. On average, patients with bowel obstruction had increased length of stay following ACS service implementation. Most surgeries in our study were performed between 16:00 hours and 08:00 hours but the introduction of an ACS significantly reduced the number of afterhours surgeries (60.0% vs. 72.6%) (ρ < 0.0001). Our survey had a response rate of 75%. Overall, surgeons on an ACS service had greater satisfaction with the organization of their call schedule than surgeons not on an ACS service.

Conclusion

Introduction of an ACS service in Saskatoon has decreased wait time to surgery and reduced the proportion of afterhours emergency surgeries, with no reduction in the length of post-surgery hospital stay. Satisfaction may be higher for surgeons in an ACS service.

Dedicated operating room for emergency surgery improves access and efficiency

BACKGROUND

Scheduling emergency cases among elective surgeries often results in prolonged waits for emergency surgery and delays or cancellation of elective cases. We evaluated the benefits of a dedicated operating room (OR) for emergency procedures available to all surgical services at a large children's hospital.

METHODS

We compared a 6-month period (January 2009 to June 2009) preimplementation with a 6-month period (January 2010 to June 2010) postimplementation of a dedicated OR. We evaluated OR use, wait times, percentage of cases done within and outside of access targets, off-hours surgery, cancellations, overruns and length of stay.

RESULTS

Preimplementation, 1069 of the 5500 surgeries performed were emergency cases. Postimplementation, 1084 of the 5358 surgeries performed were emergency cases. Overall use of the dedicated OR was 53% (standard deviation 25%) postimplementation. Excluding outliers, the average wait time for priority 3 emergency patients decreased from 11 hours 8 minutes to 10 hours 5 minutes (p = 0.004). An increased proportion of priority 3 patients, from 52% to 58%, received surgery within 12 hours (p = 0.020). There was a 9% decrease in the proportion of priority 3 cases completed during the evening and night (p < 0.001). The elective surgical schedule benefited from the dedicated OR, with a significant decrease in cancellations (1.5% v. 0.7%, p < 0.001) and an accumulated decrease of 5211 minutes in overrun minutes in elective rooms. The average hospital stay after emergency surgery decreased from 16.0 days to 14.7 days (p = 0.12) following implementation of the dedicated OR.

CONCLUSION

A dedicated OR for emergency cases improved quality of care by decreasing cancellations and overruns in elective rooms and increasing the proportion of priority 3 patients who accessed care within the targeted time.

Putting guidelines into practice: a tailored multi-modal approach to improve post-operative assessments

BACKGROUND

The Scottish Intercollegiate Guideline Network (SIGN) published Postoperative Management in Adults in 2004, advocating post-operative assessments to optimize post-operative care. Our aim was to improve post-operative assessments in a surgical high-dependency unit (HDU).

METHODS

A prospective audit of post-operative admissions to surgical HDU over two 4-week periods was performed. Medical and nursing documentations were reviewed. A tailored multi-modal approach targeting specific barriers to change was used to implement changes; education of staff, introduction of designated HDU bleeps and a post-operative assessment pro forma. Re-audit was performed after 6 months.

MAIN FINDINGS

The first cycle included 72 patients and the second included 62 patients. Time to assessment improved after changes. Forty-six (74%) patients compared with 27 (37%) patients before were assessed within 4 hours. The number of individual reviews increased and number of reviews due to nursing concerns decreased. Thirty-eight (61%) patients compared with 15 (21%) patients before were assessed through an individual review and one (2%) patient compared with 23 (32%) patients due to nursing concerns. Documentation improved. Documentation of relevant past medical history, medications, allergies, complications and post-operative instructions improved from 2 (3%), 1 (1%), 0, 8 (11%) and 26 (36%), to 18 (29%), 28 (45%), 20 (32%), 18 (29%) and 55 (89%), respectively. Difference between first and second cycles was highly significant throughout (P < 0.001).

CONCLUSION

Clinical practice was improved by a tailored multi-modal approach. Educating staff, improving communication and documentation, and re-audit has shown significant improvement. However, further improvements are required to reach best practice.

Postoperative emergency response team activation at a large tertiary medical center

OBJECTIVE

To study characteristics and outcomes associated with emergency response team (ERT) activation in postsurgical patients discharged to regular wards after anesthesia.

PATIENTS AND METHODS

We identified all ERT activations that occurred within 48 hours after surgery from June 1, 2008, through December 31, 2009, in patients discharged from the postanesthesia care unit to regular wards. For each ERT case, up to 2 controls matched for age (±10 years), sex, and type of procedure were identified. A chart review was performed to identify factors that may be associated with ERT activation.

RESULTS

We identified 181 postoperative ERT calls, 113 (62%) of which occurred within 12 hours of discharge from the postanesthesia care unit, for an incidence of 2 per 1000 anesthetic administrations (0.2%). Multiple logistic regression analysis revealed the following factors to be associated with increased odds for postoperative ERT activation: preoperative central nervous system comorbidity (odds ratio [OR], 2.53; 95% confidence interval [CI], 1.20-5.32; P=.01), preoperative opioid use (OR, 2.00; 95% CI, 1.30-3.10; P=.002), intraoperative use of phenylephrine infusion (OR, 3.05; 95% CI, 1.08-8.66; P=.04), and increased intraoperative fluid administration (per 500-mL increase, OR, 1.06; 95% CI, 1.01-1.12; P=.03). ERT patients had longer hospital stays, higher complication rates, and increased 30-day mortality compared with controls.

CONCLUSION

Preoperative opioid use, history of central neurologic disease, and intraoperative hemodynamic instability are associated with postoperative decompensation requiring ERT intervention. Patients with these clinical characteristics may benefit from discharge to progressive or intensive care units in the early postoperative period.

The postoperative anaesthetic review

An anaesthetic preoperative assessment for all patients is the standard of care in UK hospitals. The Royal College of Anaesthetists (RCoA) 2009 guidelines state that a postoperative visit, within 24 hours following surgery, is recommended for patients only in certain circumstances. This article critiques these guidelines and explores factors which must be taken into consideration when deciding whether or not anaesthetists should routinely visit their patients after they leave the recovery area. We discuss the physiological rationale for performing a postoperative anaesthetic visit; the identification of post-operative morbidity including provision of adequate post-operative analgesia; patient benefits; limitations of performing postoperative review, and the implications that expanding anaesthetists' responsibilities as perioperative physicians has had upon anaesthetic training and service provision. Finally, this article offers an alternative model for deciding when to perform a post-anaesthetic visit.

A review of risk scoring systems utilised in patients undergoing gastrointestinal surgery

INTRODUCTION

Adequate stratification and scoring of risk is essential to optimise clinical practice; the ability to predict operative mortality and morbidity is important. This review aims to outline the essential elements of available risk scoring systems in patients undergoing gastrointestinal surgery and their differences in order to enable effective utilisation.

METHODS

The English literature was searched over the last 50 years to provide an overview of systems pertaining to the adult surgical patient.

DISCUSSION

Scoring systems can provide objectivity and mortality prediction enabling communication and understanding of severity of illness. Incorporating subjective factors within scoring systems can allow clinicians to apply their experience and understanding of the situation to an individual but are not reproducible. Limitations relating to obtaining variables, calculating predicted mortality and applicability were present in most systems. Over time scoring systems have become out-dated which may reflect continuing improvement in care. APACHE II shows the importance of reproducibility and comparability particularly when assessing critically ill patients. Both NSQIP in the USA and P-POSSUM in the UK seem to have many benefits which derive from their comprehensive dataset. The "Surgical Apgar" score offers relatively objective criteria which contrasts against the subjective nature of the ASA score.

CONCLUSION

P-POSSUM and NSQIP are comprehensive but are difficult to calculate. In the search for a simple and easy to calculate score, the "Surgical Apgar" score may be a potential answer. However, more studies need to be performed before it becomes as widely taken up as APACHE II, NSQIP and P-POSSUM.

Use of the ASA Physical Status Grading System in pediatric practice

BACKGROUND

The American Society of Anesthesiologists (ASA) Grading System is widely used to describe preoperative physical status. Inconsistency of grading between anesthetists has been demonstrated in studies using hypothetical adult patient scenarios. We aimed to investigate the use and interrater reliability of the ASA Grading System in pediatric anesthesia practice.

METHODS

A two-part questionnaire was mailed to all 176 current members of the Society of Paediatric Anaesthesia in New Zealand and Australia (SPANZA). The first part of the questionnaire obtained information regarding type of practice, use of the ASA Grading System, opinions regarding grading systems in general and opinions as to the limitations of the ASA System. In Part II, respondents were presented with 15 hypothetical patient scenarios and asked to grade them using the ASA System. The scenarios were designed to cover a range of ages and conditions common in pediatric practice.

RESULTS

There were 130 replies (73.9%) after two mailings. The majority of respondents had been in predominantly pediatric practice for >5 years, had read the ASA Grading System within the last 2 years, and used it regularly. However, 30% modified the grading system for use in pediatrics. Many limitations of the ASA System in pediatric practice were identified. There was considerable lack of consistency in the grading of the hypothetical patient scenarios, with each scenario receiving at least three different ASA gradings. Case scenarios involving trauma or airway compromise were associated with greater inconsistency. There was no demonstrable correlation between grading consistency and patient age, familiarity with the ASA Grading System or experience of the anesthetist.

CONCLUSIONS

The ASA Grading System shows poor interrater reliability in pediatric practice, as it does in adults. This should be borne in mind when using the ASA System for clinical or scientific work in pediatrics. A physical status grading system developed specifically for use in pediatrics may reduce inconsistency.

Systematic review and evaluation of physiological track and trigger warning systems for identifying at-risk patients on the ward

OBJECTIVE

Physiological track and trigger warning systems (TTs) are used to identify patients outside critical care areas at risk of deterioration and to alert a senior clinician, Critical Care Outreach Service, or equivalent. The aims of this work were: to describe published TTs and the extent to which each has been developed according to established procedures; to review the published evidence and available data on the reliability, validity and utility of existing systems; and to identify the best TT for timely recognition of critically ill patients.

DESIGN AND SETTING

Systematic review of studies identified from electronic, citation and hand searching, and expert informants. Cohort study of data from 31 acute hospitals in England and Wales.

MEASUREMENTS AND RESULTS

Thirty-six papers were identified describing 25 distinct TTs. Thirty-one papers described the use of a TT, and five were studies examining the development or testing of TTs. None of the studies met all methodological quality standards. For the cohort study, outcome was measured by a composite of death, admission to critical care, 'do not attempt resuscitation' or cardiopulmonary resuscitation. Fifteen datasets met pre-defined quality criteria. Sensitivities and positive predictive values were low, with median (quartiles) of 43.3 (25.4-69.2) and 36.7 (29.3-43.8), respectively.

CONCLUSION

A wide variety of TTs were in use, with little evidence of reliability, validity and utility. Sensitivity was poor, which might be due in part to the nature of the physiology monitored or to the choice of trigger threshold. Available data were insufficient to identify the best TT.

Can physiological variables and early warning scoring systems allow early recognition of the deteriorating surgical patient?*

OBJECTIVE

Early warning scoring systems are widely used in clinical practice to allow early recognition of the deteriorating patient, but they lack validation. We aimed to test the ability of physiologic variables, either alone or in existing early scoring systems, to predict major deterioration in a patient's condition and attempt to derive functions with superior accuracy.

DESIGN

A comparative cohort study.

SETTING

A teaching hospital in Scotland.

PATIENTS

Two cohorts of general surgical high-dependency patients. The cohorts are a group of surgical high-dependency care patients who did not require intensive care admission and another group of patients who did require admission.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Prospective physiologic data on consecutive surgical high-dependency unit patients were collected and compared with physiologic data on patients admitted to the intensive care unit from the same surgical high-dependency units. Data were quality checked and summarized, and discriminant analysis and receiver operator curves were used to discriminate between the groups. There were significant physiologic differences between groups with regard to heart rate (p<.001, area under the receiver operating characteristic curve [AUC] 0.7), respiratory rate (p<.001, AUC 0.71), and oxygen saturation (p<.001, AUC 0.78) across time points. This was not present for systolic blood pressure or temperature. Existing early warning scoring systems had good discriminatory power (AUC 0.83-0.86). We derived discriminant functions, which have a high predictive ability to determine differences between groups (p<.0001, AUC 0.86-0.90). We found that heart rate and respiratory rate could detect differences between groups at 6 and 8 hrs before ICU admission, but oxygen saturation and the discriminant function 2 could detect differences 48 hrs before ICU admission.

CONCLUSIONS

Some commonly used physiologic variables have reasonable power in determining the difference between patients requiring intensive care unit admission, but others are poor. Existing early warning scores have comparatively good discriminatory power. We have derived functions with excellent predictive power in this derivation cohort.

Clinical review: Outreach - a strategy for improving the care of the acutely ill hospitalized patient

We examined the literature relating to the safe care of acutely ill hospitalized patients, and found that there are substantial opportunities for improvement. Recent research suggests substantial benefit may be obtained by systems of outreach care that facilitate better integration, co-ordination, collaboration and continuity of multidisciplinary care. Herein we review the various approaches that are being adopted, and suggest the need for continuing evaluation of these systems as they are introduced into different health care systems.

Optimisation of oxygenation and tissue perfusion in surgical patients

Surgical patients with limited cardiovascular reserve have much worse prognosis than patients with normal hearts. This review identifies 17 randomised controlled clinical trials that have investigated peri-operative therapy designed to increase tissue perfusion in surgical patients, many of whom have limited cardiovascular reserve. Although there are differences which make equating the trials complex, a total of 1974 patients have been enrolled in the studies and the odds ratio for reduction in mortality is 0.45 (95% confidence intervals 0.33-0.60). Further research needs to be undertaken in the identification of patients with limited cardiovascular reserve and for investigating proposed treatment strategies. Despite this, it appears that such patients have improved outcome if they are admitted to intensive care unit pre-operatively and have suitable therapy given to improve tissue oxygen delivery.

The ASA Physical Status Classification: inter-observer consistency. American Society of Anesthesiologists

The American Society of Anesthesiologists (ASA) physical status classification system has previously been shown to be inconsistently applied by anaesthetists. One hundred and sixty questionnaires were sent out to all specialist anaesthetists in Hong Kong. Ten hypothetical patients, identical to those of a similar study undertaken 20 years ago, each with different types and degrees ofphysical disability were described. Respondents were asked about their country of training and type of anaesthetic practice and to assign an ASA classification status for each patient. Ninety-seven questionnaires were returned (61%) after two mailings. Agreement for each patient within groups, between groups and overall comparisons were made. Percentage of agreement was between 31 to 85%. Overall correlation was only fair in all groups (Kappa indices: 0.21-0.4). We found that the current pattern of inter-observer inconsistency of classification was similar to that 20 years ago and exaggerated between locally and overseas trained specialists (P<0.05). The validity of the ASA system, its usefulness and the need for a new, more precise scoring system is discussed.