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PRE-OPERATIVE ASSESSMENT:
Anaesthesia and You
Dr. Ryck Albertyn
?
•Who Are we
•What do we do
Pre-op
Intra-op
Post-op
-analgaesia
-N&V
-Fluids
•When do we do the preoperative assessment
anaesthetic clinic
day before
on the day
? How do we do it
Physiology
Pathology
Anatomy
Pharmacology
Procedure
Pre-operative assessment / visit
A
-
rapport
B
-
history and physical examination
C
D
-
order special investigations
assess the risks of anaesthesia and surgery
– postpone or cancel
E
-
institute pre-op management
F
-
prescribe pre-medication
G
-
plan anaesthetic management
A
Establishment of rapport
-Anxiety
-Intra and post-op management
-Pain relief
-N&V
B
History and physical examination
House Officer notes are very important!
History:
•Family history: porphyria, MH, increased cholesterol, haemophilia,
suxamethonium sensitivity, neurological conditions, previous
anaesthesia
•CVS:
IHD esp. MI, cardiac failure symptoms
•Respiratory: asthma, COAD
•GIT
esp. liver
•Endocrine:
DM, thyroid, steroids
•Neurological and connective tissue diseases e.g. RA
•Pregnancy
•Smoking and alcohol
•Drugs
recreational
therapeutic (interactions)
•Allergies
•Previous anaesthesia
•Teeth
Physical Examination
“EYEBALL”
Full examination but maybe directed to systems
identified in history or of importance
Airway
Breathing
Circulation
Neurological, musculoskeletal esp. spine etc.
Bedside manoeuvres
CVS
Respiratory
Autonomic
PEFR
C
Special investigations
? Useful
? Change my management
? (Medicolegally defensible)
Bloods
FBC –
males > 50 yrs, all females, major surgery, when
clinically indicated, all Asian patients
U&E > 50 routinely, D&V, metabollic diseases, ileus, renal or
hepatic disease, medications (diuretics digoxin, steroids,
hypoglycaemics)
Coagulation – anti-coagulants; sepsis
Blood sugar – DM; steroids
LFT’s –
liver diseases; abnormal nutrition, heavy alcohol intake
(> 80g per day)
ABG –
dyspnoea, thoracic surgery, severe COPD for major
surgery (abdominal)
Radiological Investigations

CXR - > 60; as indicated by history and examination,
CA with metastases, thoracic surgery; recent immigrants
(TB)
 C-spine – RA with decreased neck movement (flexion/
extension)
 Thoracic inlet views
 Echocardiography – murmurs of significance (usually
associated with symptoms/clinical science)
Additional investigations
 Pulmonary function tests – severe dyspnoea on mild to
moderate exertion; COPD for laparotomy/thoracic
surgery
 Stress ECG/treadmill
D
Risk Management




? Optimal condition
yes – surgery
no – optimise – treatment/consultation
? Risk – benefit ratio
Mortality
Surgery = 60:10,000 (0.06%)
Anaesthesia = 1:10,000 (0.001%)
ASA grading
ASA I
ASA II
ASA III
ASA IV
ASA V
E
A normally healthy individual
A patient with mild systemic disease
A patient with severe systemic disease that is not
incapacitating
A patient with incapacitating systemic disease that is a
constant threat to life
A moribund patient who is not expected to survive 24 hrs with
or without operation and
Emergency suffix
Mortality Rates per ASA Grade (%)
ASA I
0.1
ASA II
1.8
ASA IV
7.8
ASA V
9.4
Causes for Postponement of Surgery
 Acute URTI – nasal secretions, pyrexia,
productive cough
 Existing disease – not fully optimised
 Emergency surgery with inadequate
resuscitation
 Food ingestion
 Lack of informed consent
CVS Disease
MI/IHD
 peri-operative MI
0.1-0.4 % in previously healthy patients
3.2 - 7.7 % in patients with previou
 most occur on the 3rd post-operative day (oxygen),
50% are silent
 40-60% mortality
 time interval since last MI very important – 6 month
gap before elective surgery
Hypertension
 Age
 Anxiety
 Multiple measurements important




DBP > 110 mmHg
Noxious stimuli
Hypotension
Tachycardia
Note: These patients’ BP’s are very variable under
anaesthesia therefore control is important
MI
Goldman Risk Index
Risk Factor
•
•
•
•
•
•
•
•
•
Points
3rd heart sound/JVP
MI in preceding six months
Rhythm other than sinus or PAC’s
> 5 VE’s/minute
Abdominal, thoracic, aortic operation
Age > 70 yrs
Important aortic stenosis
Emergency operation
Poor condition:
PAO2 < 8 kPa
PACO2 > 6,5 kPa
K < 3 mmol/l
HCO3 < 20 mmol/l
Urea > 7,5 mmol/l
Creatinine > 270 micromol/l
SGOT abnormal
Chronic liver disease
11
10
7
7
3
5
3
4
3
TOTAL
53
Risk of Major Cardiac Complications (%)
Points
0-5
6-12
13-25
26-53
0.3-3%
1-10%
3-30%
19-75%
Pulmonary Disease
 Asthma
PEFR, steroids, pre-operative nebulizers/inhalers
Current condition
 COPD
PEFR, steroids, pre-operative nebulizers/inhalers
Current condition
 Restrictive lung disease
PFT’s, current condition
 Neoplasia
collapse, V/Q mismatch, metastases (liver, brain)
 Previous surgery (pneumonectomy – TB)
Endocrine
Diabetes Mellitis
FIRST ON THE LIST
Pre-op visit:
 ? Glucose control
 Ketosis
 Treatment regimen
 NIDDM
 IDDM
 Complications
 Autonomic
Postural hypotension
Loss of sinus arrythmia
 Peripheral
 Renal function
Hypertension/IHD – silent infarction
Management of Diabetes Pre-Operatively
Aim – minimise metabolic disturbance by providing adequate
glucose and calories and insulin in order to prevent
hypoglycaemia, proteolysis, ketogenesis and acidosis.
Ketosis Kills!
Diabetes - Pre -operative management principles I
A] Minor Procedure (< 1hr; minimal blood loss etc.)
NIDDM
- normal regimen until midnight (snacks)
- omit morning hypoglycaemic
- BM prior to theatre
IDDM
- normal regimen until midnight (snacks)
- omit morning insulin, 5% Dex, BM
- if poorly controlled -- Insulin Sliding Scale
(2-4 hrly BM’s)
Diabetes - Pre -operative management principles II
NIDDM + IDDM
• Normal regimen until midnight
• 5% dextrose 1000ml 8 hrly from midnight
• Insulin Sliding Scale (2-4 hrly BM’s)
• Continue ISS until normal nutrition and hypoglycaemic
regimen re-established
Thyroid Disease
Patients must be euthyroid
 Clinical signs and symptoms
 Bloods – TFT’s
Blood Ordering
E
Pre-operative Preparation
• Respiratory disease
Physiotherapy
Antibiotics
Bronchodilators
• Cardiovascular disease
SBE prophylaxis
Hypertension
Acute resuscitation
• Diabetes - ketosis
• Emergency Surgery - acute resuscitation
F
Pre-medication
Aims
 Allay fear and anxiety
 Decrease secretions
 Additive effect with general anaesthetic
 Decrease post-operative NNV
 Amnesia
 Decrease aspiration risk
Decrease volume and pH
 Decrease vagal reflexes
Eye surgery; anorectal surgery
Repeated suxamethonium
Children
 Decrease sympatho-adrenal response
Drugs
 Benzodiazepines – anxiolysis
 Opioids
Pain pre-op
Smoother inter-operative course
Sedation without anxiolysis
Side effects – nausea and vomiting,
respiratory depression/delayed recovery,
and histamine release
 Phenothiazines
Advantages
Disadvantages
Miscellaneous Tail-Notes
Acute pain
 IV morphine (4mg + 2mg/5mins until
comfortable
 Diclofenac
Bowel preparation
 Fluids!
 Maintenance 1-2ml/kg/hr
G
Plan Anaesthetic Management