Pre Op Assesment of the High Risk Surgical Pat

8/14/2019 Pre Op Assesment of the High Risk Surgical Pat

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Pre Operative Assessment Of TheHigh Risk Surgical Patient

Lui G Forni & NG LaviesDepartment of Critical Care

Worthing & Southlands Hospitals


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Introduction

Identifying the High Risk Patient Risk Scoring

CVS Risk Assessment How we have addressed the problem Future Developments


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Introduction

Over 20,000 patients a year diefollowing surgery

Most die within 30 days of surgery ongeneral wards


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Introduction

Improved Surgical Outcomes Grouprecommended (2005)o improved pre-op assessment

o improved intra-operative careo improved use of post operative resources

This followed Association ofAnaesthetists guidelines

Hopefully should lead to improvedoutcomes


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How Do We Identify The High RiskSurgical Patient?

Surgical Factors Patient Factors


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Surgical Factors

Different operations have different mortalityrates

0.5% for elective THR13% for elective oesophagogastrectomy

Emergency operations have higher mortality10.7% for elective surgery patients

36.8% for emergency surgery patients


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Urgency and Operative Mortality

Mella BJS 98 Colorectal surgery

audit Operations carriedout urgently have ahigher mortality

rate for same ASA


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Surgical Factors

High Risk (>5%) Major emergency

procedures eg acuteabdomen, major trauma

Aortic/major vascularsurgery

Prolonged surgery withlarge fluid shifts/bloodloss

Peripheral vascular

surgery

Intermediate Risk (


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Patient Factors

Age

Existing Co-morbidity Exercise Tolerance Medication


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Patient Factors : Age

Higher number of concurrent diseaseprocesses

Decline of physiological reserve withageing(cardiovascular/pulmonary/renal/musculoskeletal)

? Increased morbidity & mortalitywith age


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CEPOD Deaths by Age 1998/9


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Effect of Age on Mortality Post Op(NCEPOD 2001)

Age in Years

%of

Total

Deaths/

Operation

s


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Patient Factors

Age Existing Co-morbidity


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Co-existing Medical Problems and

Perioperative Death(NCEPOD 2002)

e of patients


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Patient Factors : CardiovascularDisease

Approximately 75% of patients whosuffer perioperative death have

cardiovascular disease


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Patient Factors : CardiovascularDisease

Risk factors for cardiovascular deathwithin 30 days of operationHowell SJ et al BJA 1998;80:14o Previous MI (odds ratio 4.04)o Angina (odds ratio 3.55)o Hypertension (odds ratio 2.53)o Renal Failure (odds ratio 4.23)o Cardiac Failure (odds ratio 2.8)


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Pre-operative Risk Scoring

Various Scoring Systems Published:o ASA (1963)o Goldman Cardiac Index (1977)o Detsky Cardiac Index (1986)o Possum (Copeland 1991)o Lee Revised Cardiac Index (1999)


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Pre-operative Risk Scoring

ASA1.Fit, healthy patient Mild systemic disease

Severe systemic disease-limitingactivity but not incapacitating

Incapacitating systemic disease-a

constant threat to life Moribund-not expected to survive


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Lee Cardiac Risk Index(Lee et al Circulation 1999; 100:1043)

6 Point Score one for each of the following: High risk surgical procedure

History of IHD History of CCF History of Cerebrovasular disease Insulin-dependent diabetes mellitus

Chronic renal failure (creatinine >177)


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Lee Cardiac Risk IndexValidated in 1422 non-cardiac surgical patients

Risk of major cardiac complications(MI, pulmonary oedema, VF or primary cardiacarrest, complete heart block)

0 point = 0.4% 1 point = 0.9% 2 points = 7% 3 or more points = 11%


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Lee Cardiac Risk Index

Applied to 1351 major vascular surgicalpatients (Boersma et al 2001)

1 point = 1.3% risk (of MI or death) 2 points = 3.1% risk 3 or more points = 9.1% risk


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Cardiovascular Risk Assessment

How can we assess cardiac risk?

Static Testingo Electrocardiographyo Transthoracic Echocardiographyo Transoesophageal Echocardiographyo Cardiac catheterisation

Dynamic Testing


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Improving Risk stratification:

Dynamic Testingo Exercise Toleranceo Exercise ECG testingo Dobutamine stress echoo Dipyridimole stress echoo Dipyridimole thallium scintigraphyo Cardiopulmonary exercise testing


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Pre-operative Functional Assessment

1 MET = 3.5 ml O2 / kg / min (Oxygenconsumption by 40 yo 70 kg man at rest)

1 MET = eating and dressing 3 MET = light housework, walking 100m, golfing

with a cart, slow ball-room dancing 4 MET = climbing 2 flights of stairs 6 MET = short run

>10 MET = able to participate in strenuous sport


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Exercise Tolerance and RiskReilly DF et al Arch Intern Med 1999;159:2185

600 patients undergoing major non-cardiacsurgery

If unable to walk 4 blocks and climb 2

flights of stairs = poor exercise tolerance ie< 4 METs Patients with poor exercise tolerance had

twice the incidence of perioperative

complications (cardiovascular andneurological) 20% vs 10% p


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Cardiopulmonary Exercise Testing

Myocardial ischaemia in absence of heartfailure has little effect on outcome (Olderet al 1993)

CPET is an objective test to determine pre-operative fitness

Correlates well with post operative survival

Can identify patients with an increased riskprofile where surgery may be inappropriate


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Examines the ability of the CVS to deliveroxygen to tissues under stress

If a patient is unable to elevate oxygendelivery to the required levels they are morelikely to have a poor outcome


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The patient is asked to exercise at a knownwork rate on some form of ergometer while anumber of variables are measured:o (1) ECGo (2) Blood pressure;o (3) Expired air flow;o (4) O2 uptake from the air;o (5) CO2 output from the body;o

(6) Arterial blood gases.


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Parameters Measured

VO2 - volume of oxygen consumedo ml/min (absolute)o ml/kg/min (relative)

METS - metabolic equivalentso 1 MET = 3.5 ml/kg/min

VCO2 - volume of carbon dioxide producedo ml/min


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Parameters Measured

During exercise, when rise in VCO2 becomesdisproportionate to rise in VO2

Indicates the level of exercise where body

has reached maximal aerobic capacity

Termed the Anaerobic Threshold


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Anaerobic Threshold by Age


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Cardiopulmonary Exercise TestingOlder P. et al Chest 1993; 104: 701


187 major abdominal surgical patients over 60

Defined the Anaerobic threshold by exercise testing

Anaerobic

threshold 11 ml/min/kg

N=132

Mortality rate 0.8%


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4 METS = 14 ml/kg/min O2 consumptionBUT

80% of elective major abdominal cases have

an AT of < 14 ml/kg/min Only those with AT < 11 ml/kg/min (32%) arehigh risk

Clinical differentiation between these

groups not possible CPX testing required to identify the highrisk group


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Does It Work?

548 Patients having major abdominal surgery

ICU (28%)

7 died (4.6%)

AT < 11 ml/min/kg

+ aortic / oesophagealsurgery

AT > 11 ml/min/kg+

Myocardial Ischaemia

AT > 11 ml/min/kgNo

Myocardial ischaemia

HDU (21%) Ward (51%)

2 died (1.7%) 0 died (0%)


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Now we have identifiedthe high-risk patient:

What do we do next?


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The SPAM Clinic

Consultant Lead Allows Medical & Anaesthetic Review

Assess patient Discuss pre/post operative care ?Assess risk


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The SPAM Clinic

Had several perceived potential benefitso Both clinicians actively involved in ITU and

manage the patients post operativelyo

Outpatient assessment enables relative easein ordering appropriate investigations andfollow up

o Allows objective assessment of the patient

by 2 experienced clinicians and shouldprevent cancellations


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The SPAM Clinic

Routine pre-assessment is still performed inour trust

Where problems arise the SPAM clinic allows apoint of easy referral

Referral occurs fromo surgical colleagues where they feel additional

assessment is requiredo anaesthetic colleagues

All major surgery requiring ITU post operativelyis referred routinely


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The SPAM Clinic

Does it work?

The results shown are from the initial

125 patients seen in the SPAM clinic

Follow up data was collected from the

patient notes or GP after 6 months


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Referral Pattern

13.069.07218%Upper GI

12.470.64559%Surgery

2.129.503%O&G

8.180.05215%Orthopaedics

8.977.69323%Urology

SDAgeMaleTotalSpeciality


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Results

90 deemed fit for surgery 33 deemed unfit

2 refused surgery (?SPAM Effect)

No significant differences between thegroups other than age


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O F Cli i /S


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Outcomes From Clinic/Surgery

36.41233Unfit

Patients

9.7992Fit Patients

Mortality

(%)

6 Month

Mortality

Number

C f D th


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Causes of Death:

01Refused Surgery

11Other

10GI Bleed

22CVA40Myocardial Infarct

45Disease Progression

UnfitFit


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R lt


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Results

No! Not the whole story.. 9 patients of the 92 deemed fit for surgery died

within 6 months of assessment But 6 died before operation

o 1 refused surgeryo 2 died of CVAso 3 died of disease progression and deemed

inoperable

Only 3 died within 6 months of surgery whohad surgery


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C l i


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Conclusions:

The introduction of the SPAM clinic hasprovided a useful service to our trust

Has allowed those deemed

inappropriate for surgical intervention tobe cancelled in good time

Allows other treatment to be instigated

where appropriate.

C l i


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Conclusions:

Most encouragingly the overall operativerisk in those deemed high risk is verylow

? Our threshold is too high

Hopefully preoperative risk stratificationwill be improved further with theintroduction of CPET

Th k Y F Li t i


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Thank You For Listening

Pre Op Assesment of the High Risk Surgical Pat

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