Transcript 2010-2011 Preoperative assessment

Preoperative assessment
Yr 4 Anaesthesia Clerkship
Dr Patricia Chalmers
2010-2011
•Objectives of preoperative assessment
•Fasting status
•The airway
•Volume status
•Systemic effects of anaesthetic agents
•Allergies and genetic considerations
•Risk Stratification
•Respiratory and cardiovascular assessment
•Patient sketches
•Overview of history and examination
Preoperative Assessment
Objectives
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To deliver good quality care
To establish doctor-patient rapport
To establish a clinical picture of the patient
To identify risk factors
To draw up a management plan
To optimise any concurrent medical conditions
To minimise the occurrence of critical incidents
in the perioperative period
Clinical Picture
Full medical history and physical examination
Points of specific relevance to anaesthesia:
RISK STRATIFICATION
General health of patient and functional
capacity
Surgical procedure
Concurrent medical conditions and medication
History of reactions and allergies to anesthesia
THE AIRWAY
Fasting Status Volume Status
FASTING STATUS
FASTING STATUS
6 hrs solids
4hrs liquids
(2hrs clear fluid /water)
The Full Stomach
Mechanisms
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Reflux
Delayed gastric emptying
Raised abdominal pressure
Pharyngeal and laryngeal incompetence
The Full Stomach
Clinical conditions
GORD
Opioids
Autonomic neuropathy: diabetes
Pregnancy
Intestinal obstruction
Trauma
Head Injury
Myopathies/ bulbar palsy
Preoperative measures to
reduce risk of aspiration
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Proton pump inhibitors
H2 blockers
Metoclopramide
0.3M Sodium citrate 30ml
Nasogastric tube where applicable
(Induction of anaesthesia: RSI)
THE AIRWAY
THE AIRWAY
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Examination Facial swelling
Mouth opening
Dentition
Macroglossia
MALLAMPATI GRADE
Thyromental distance
Neck shape and mobility
Mallampati Grades
Mallampati Grades
Volume Status
VOLUME STATUS
Assess preoperative deficit
a. Clinical picture
b. Formula
Volume Status
TBW 70kg male
55-60% Body weight 45l
Intracellular 30 L
Extracellular 15 L
interstitial 12L
intravascular 3L
Clinical Dehydration
Body wt loss
5%
S&S
thirst, dry mouth
5-10%
reduced peripheral perfusion,
reduced skin turgor, oliguria,
postural hypotension, tachycardia
reduced CVP, lassitude,
10-15%
inc RR, hypotension, anuria,
delirium, coma
>15%
Life threatening
Formula
• 4mls/kg/hr for first 10 kg body weight
• 2mls/kg/hr for the next 20kg body wt
• 1ml/g /hr for every other kg body weight
• Adult 2mls/kg/hr
Fluid replacement
• Replace existing deficit: 50% deficit in 1st hr,
25% in 2nd hr,
25% in 3rd hr
• Maintain fluid balance 2mls/kg/hr
• Deficit: fasting/ burns/GI losses
• Consider ongoing losses
Effects of anesthetic agents and drugs
• Respiratory depression, impaired lung function →, HYPOXIA
• Depressed myocardial function →HYPOTENSION
arrthymias,
• Impaired delivery of O2 to the tissues
Effects of anaesthetic agents on
respiratory function
• Depression of RC
• Diminished muscle tone
• Reduced lung compliance(loss of elastic
recoil)→ ↓TLC ↓TV ↓FRC and ↑Closing
volume
• Atelectasis
• ↑Dead space(respiratory circuit)
Increased work of breathing
Increased ventilation /perfusion mismatch
Effects of anaesthetic agents
on cardiovascular function
Reduced contractility
Reduced stroke volume
Vasodilatation
Hypotension
Risk of reduced coronary perfusion
perfus
Effects of anesthetic agents and drugs
(contd)
• Metabolism and elimination of drugs dependent
on hepatic and renal function
• Muscle relaxation and paralysis
• Stress Response
• Adverse effect on co-morbidities
Perioperative Clinical Risks
• Respiratory depression
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Cardiac ischaemia
Arrthymias
Myocardial infarction
Stroke
Renal impairment
Risk Stratification
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ASA grades
Surgical procedure
Age
BMI
Elective v Emergency
ASA GRADING
1. Healthy Patient
2.Mild systemic disease with no impact on
life
3.Systemic disease with limiting factors
4. Systemic disease with a constant threat to
life
5. Moribund patient
Grading of General Surgical
Procedures
1. Minor eg skin lesion
2. Intermediate eg inguinal hernia
arthroscopy
3. Major eg hysterectomy,
4. Major+ eg colonic resection, radical neck
dissection,
Preoperative assessment
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Is there any evidence of active disease?
Are there any clinical risk factors?
What is the patient’s functional capacity?
What maintenance medication is the
patient on?
• How can we optimise the patient’s clinical
condition?
Patient sketch 1
• 53 year old female for ligation of varicose veins
• She has a history of asthma and neglects her
medication
• o/e anxious
• RR 24/min
• widespread rhonchi
• PEF 65%
• Other systems unremarkable
Patient sketch 2
• 64 yr old male with intestinal obstruction
for a laparatomy
• History of COPD previous heavy smoker
• Gets breathless walking uphill or fast on
level ground
• Coughing purulent sputum
• FEV1 75%
• On combined therapy with beta 2 agonist
and anticholinergic
Preoperative measures to improve
lung function
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Stop smoking
Chest physio
Bronchodilators
Antibiotics
Steroids
Patient sketch 3
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55yr old female for hysterectomy
Diabetic on twice daily insulin
BP 140/90
What investigations and management
Patient sketch 4
22 kg child for removal of plaster cast
Fasting from midnight
In theatre at 10.00am
What is her fluid deficit?
Patient Sketch 5
84 yr old female with a fractured neck of
femur
Tripped in bathroom lives alone and lay
there for 20 hours
She is thin stature, lives on tea, toast and
cake
History of CCF
On diuretics
? Considerations and management
Patient Sketch 6
40 yr old male for elective cholecystectomy
Heavy smoker
HR 80/min BP 200/115
Hb 14.0 gm/dl
Urea 8 mmols/l
Creatinine 140mmols/l
Patient sketch 7
40 yr old male for cholecystectomy
HR 80/min reg
BP 150/95
Hb 12.8 gm/dl
Urea 5.8 mmols/l
Creatinine 115 µmols/l
Na 130mmols/l
K 4.5mmols/l
Patient sketch 8
• 44 year old female for mastectomy and
reconstruction
• 5 year history of angina, becoming more
frequent and increasing in severity over past 6
months
• Both parents died from myocardial infarction
• Coronary angiogram 2yrs ago no vessel disease
• Ca antagonists,glyceryl trinitrate, isosorbide
dinitrate, verapamil,
Risk Factors Investigations Management
Perioperative Cardiac Risk in
relation to noncardiac surgery
• Hi >5%: Vascular Aortic and peripheral
vascular surgery
• Intermediate 1-5%: intraperitoneal,
intrathoracic, carotid endarterectomy,
head and neck , orthopaedic, prostrate,
• Lo risk <1%: endoscopic, superficial,
cataract, breast, day stay procedures
ACC/AHA 2007 guidelines
Preoperative measures to improve
cardiovascular status
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Continue maintenance meds
Control heart failure
Stabilise arrthymias
Stabilise uncontrolled hypertension
Lo dose short acting beta-blockers for IHD
if Hi or intermediate risk
• Statins considered
• Prophylactic antibiotics for valvular
disease/prosthesis
Systematic enquiry
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RS
CVS
GIT HH GORD PUD
Renal system
Hepatic system
Endocrine diabetes thyroid
Bone joint and ct disorders RA
Haemotological anaemia coagulopathy DVT
Neurological and muscular epilepsy
Systematic Enquiry (contd)
• Medications Diuretics, Steroids,
Diabetes, Epilepsy, Anticoagulants etc
• Allergies
• Social history Smoking, Alcohol
• Previous Anaesthetic history PONV
• FH genetic disorder SUX apnoea MH
• Fasting status 6hrs (2hrs clear fluids)
Investigations
Age
ASA
Surgery
Spec cons
FBC
Elderly
2-5
2-4
Pallor
hge
U&E’s
Elderly
3-5
3-4
Dehydration
3-4
Polytrauma
G&H/ Xmatch
ECG
M>40,
F>50
CXR
CVS 2 2
RS 3
CVS 2
RS 3
Pneumonia
INVESTIGATIONS
– FBC
– U&E’S
Where indicated
– Group & Hold/X-match
– ECG
– CXR
– Glucose
– Coag screen (spinal, epidural)
– BGA
– Cardiac ultrasound
– RFT’s
Key Points (1)
History: Full systemic history
• Medications for maintenance
• Allergies
• Add previous anaesthetic history PONV
• FH Sux apnoea, MALIGNANT HYPERTHERMIA
FASTING status
Anaesthetic Risk Stratification
Key Points (2)
Examination: Full systemic examination
Add THE AIRWAY
Consider Volume status G&H/X-match
Obtain Consent
Discuss pain management ---reassure
Continue maintenance meds
Draw up Anaesthetic Plan
Bear in mind effects of anaesthesia on
patient and effects of co-morbidities on the
anaesthetic technique
Recommended Reading
Neville Robinson, George Hall
“How to Survive in Anaesthesia”
BMJ Books 2nd Ed 2002