Statistical Publication Notice

(30/October/2007)

Scottish Intensive Care Society Audit Group Audit of Critical Care in Scotland 2005/2006 

INTRODUCTION/CONTEXT

The Scottish Intensive Care Society Audit Group (SICSAG) has maintained a national database of patients admitted to adult general Intensive Care Units (ICUs) in Scotland since 1995.  The purpose of the audit is to improve patient care.  In order to examine this comprehensively we collect information including demographics, severity of illness, diagnosis, interventions and outcomes, electronically in general ICUs.

Data were collected prospectively from all general adult ICUs and the majority of High Dependency Units (HDUs) using the Ward Watcher system developed for this purpose. Staff from ISD collected the data during visits to units between January and August 2007.  We are reporting on activity for 2005 and 2006 and have also included some HDU data for the first time, in order to provide a more complete picture of Critical Care. Although we were not able to collect outcome data for HDUs in time for this publication, it will be available on the website where more detailed hospital and board specific information can also be found (www.scottishintensivecare.org.uk  or www.sicsag.scot.nhs.uk ).

The format of the report follows the patient journey in three sections: demographics, interventions and outcomes. Information is reported on over 15,000 ICU admissions and over 30,000 HDU admissions to Scottish hospitals during 2005 and 2006. 

-----------------------------------------------------------------

KEY POINTS (3 - 5)

Critical Care is an essential support to both Unscheduled Care and Planned Care. There were over 25,000 admissions to Scottish Critical Care units in 2006. Admissions to ICU have increased by 32% over the last 10 years. Over the same period, the length of stay has typically been about 5 days.

Over half of admissions to Critical Care occur outside ?normal working hours?. This is particularly marked in ICU and should be taken into account when determining staffing levels.

There has been a statistically significant increase in both the number and proportion of patients admitted to ICU from the Emergency Department.

There has been a steady improvement in case mix adjusted mortality rates in Scottish ICUs over the last four years, and the variation between units is reassuringly small.

-----------------------------------------------------------------

INTERPRETATION (any issues that readers should be aware of)

Local and regional audit co-ordinators from the Scottish Trauma Audit Group (STAG) have undertaken extensive validation of selected core data items, however we plan to undertake more detailed, prospective validation of the data (involving case note review) in the future.

Hospital identification codes for sections 1 and 2 are located on the inside flap of the front cover and identifier codes for section 3 are held by the lead audit Consultants (page 43).

Interquartile Ranges and Funnel Plots

These are two methods used in the report for illustrating the differences between units.  In the former methods, units are represented by a series of vertical lines showing the range within which a quarter and three-quarters of admissions/patients respectively occurred, while the horizontal dashes represent each unit?s median value.  In the latter method, units between or above the upper funnel lines have a significantly higher rate than average for the graphed data, whilst those between or below the lower lines have a significantly lower rate. 

When utilizing either method, a unit?s divergence from the norm should be interpreted with caution. Although the degree of difference is highlighted in these figures, the reason for that difference is not explained and no judgements regarding ?good? or ?bad? practice are made. There may be many reasons for such variations relating to case mix, external factors, or different clinical approaches.

APACHE II

The outcome measure used by SICSAG is the patient?s survival status (alive or dead) when they finally leave hospital (even if this is not the original hospital). Patients admitted to ICUs are at significant, but varied, risk of death. Simply comparing the proportion of patients who die in each unit can give a misleading impression because the severity of their illnesses is different. To overcome this, we use the APACHE II system to adjust for case mix.

APACHE II produces an expected mortality rate for a unit which can be compared to the actual observed mortality rate to give a standardised mortality ratio (SMR). An SMR significantly greater than 1 suggests that mortality is higher than expected, and a value of less than 1 that it is lower than expected. It is important to interpret SMR?s with caution. It should be appreciated that whilst the system adjusts for case mix, it does not do so perfectly, as has been highlighted in previous reports, and also it is now nearly 30 years old. Many units admit a relatively small number of patients each year and the confidence intervals around the SMR are therefore wide.

-----------------------------------------------------------------

DETAILED FINDINGS / COMMENTARY

Section1: Demographics

Number of Admissions

There has been a gradual but cumulatively significant increase in the number of patients admitted since 1995. In 2006, there were 9,883 admissions to ICU and 15,378 to HDU. Critical Care has become a key support for both emergency and planned care in NHS Scotland.

Occupancy

The average Scottish Critical Care bed occupancy (real time recording) is now 74%. It has fallen slightly despite the increase in admissions, but remains high.

Length of Stay

Whilst median length of stay for both ICU and HDU is around 2 days, the mean is close to 5 days for ICU and 3 for HDU. The reduction in mean length of stay in ICU between 2005 and 2006 is statistically significant.

Variations in length of stay between units should certainly raise questions, but may reflect differences in case mix or service provision at a local level.

Time of admission

41% of ICU admissions, and 28% of HDU admissions occur after 8pm.  Taking into account weekend admissions it is seen that over half of ICU admissions are ?out of hours?. The figure is marginally lower for HDU.

Location prior to admission

There has been a steady increase in the number and proportion of patients admitted from the Emergency Department, although the operating theatre remains the most common single source of admissions.

The majority of post-operative admissions to ICU follow emergency surgery, but in HDU planned surgery predominates.

Section 2 Interventions In Critical Care

Intensive Care

Invasive ventilation

The proportion of patients admitted to ICU who receive invasive ventilation via an endotracheal tube or tracheostomy has fallen slightly since 1999 although the absolute number has increased.

Renal replacement therapy (RRT)

The proportion of patients who undergo renal replacement therapy, in the form of either dialysis or haemofiltration, has increased in recent years.  This procedure is much more common in some units than others.

Pulmonary artery flotation catheters (PAFC)

Use of this method of invasive cardiovascular monitoring has reduced markedly, almost disappearing in most units, whilst a small number continue to make frequent use. The use of both pulmonary artery catheters is controversial (Rubenfeld 2007), and units might wish to review their practice.

Cardiovascular support

About 40% of patients receive inotropes or vasopressors at some point in their ICU stay.

High Dependency

Non-invasive ventilation

Ventilation using a face mask only occurs frequently in two HDUs, both of which are in Edinburgh. This may be because the technique is undertaken elsewhere (in ICU or respiratory wards for example) in other hospitals, or may reflect a different management approach.

Cardiovascular support

The proportion of patients who receive such support in HDU is surprisingly low, with two specialist units showing a different pattern.

Section 3 Outcomes

The variation in unadjusted mortality rates between units is largely due to the different patient populations, and does not allow any judgments to be made about quality of care.

The Standardised Mortality Ratio (SMR) for patients admitted to ICU in Scotland has fallen over the last five years from 1.05 to 0.92, indicating improved outcomes.

The pattern of SMRs across Scotland is reassuringly uniform.

-----------------------------------------------------------------

MAIN CONTACTS:

Diana Beard/Project Manager (STAG)
Tel 0131 242 3862
diana.beard@luht.scot.nhs.uk

Simon Mackenzie/Chair (SICSAG)
Tel 0131 242 3200
simon.mackenzie@luht.scot.nhs.uk

Angela Kellacher/Clinical Co-ordinator (SICSAG)
Tel 0131 242 3862
angela.kellacher@luht.scot.nhs.uk

-----------------------------------------------------------------

PRE-RELEASE ACCESS TO THIS PUBLICATION WAS GIVEN TO:

Chief Executives and Medical Directors of participating Scottish Health Boards:
NHS Ayrshire and Arran, Borders, Dunfries and Galloway, Fife, Forth Valley, Grampian, Greater Glasgow and Clyde, Highland, Lanarkshire, Lothian, Shetland and Tayside.

Chief Executives and Medical Directors of participating Hospitals:
Ayr, Crosshouse, Borders General, Dunfries and Galloway, Queen Margaret Dunfermline, Victoria Kirkcaldy, Stirling Royal, Aberdeen Royal, Gartnavel, Glasgow Royal, Inverclyde, Royal Alexandra Paisley, Stobhill, Southern General, Victoria Infirmary Glasgow, Western Infirmary Glasgow, Raigmore, Hairmyres, Monklands, Wishaw, Royal Infirmary Edinburgh, Western General Edinburgh, St Johns Hospital, Gilbert Bain, Ninewells, Perth Royal.

Scottish Government Health Department

Chief Medical Officer, Dr Harry Burns

Deputy Head of Analytical Services Division, Ms Elaine Drennan
-----------------------------------------------------------------

HISTORY OF THIS PUBLICATION:

Last Published:  November 2005
Next Due:  November 2008
Date available since: First report containing 1995-1997 data published during 1998.