Transcript Preanaesthetic Assessment - Neurological Society of India

Preanaesthetic
Assessment in
neurosurgical patient
DR. BHARATI KONDWILKAR
Neuroanaeshetist
Objectives
Optimize quality of care
Minimize last minute cancellations
Evaluate patient’s
1. Medical history and neurological events
2. Physical examination and neurological status
3. Investigations
4. Past medical records
Objectives
Minimise risk for anaesthesia
Plan anaesthetic technique
Plan peri-operative care
Develop a rapport with patient
Inform and educate patient /relative
Ensure patient safety
Consent for anaesthesia
Neurological system
History of
Seizures,
Neurological deficits,
Signs and symptoms of raised (ICP)
Transient ischemic attacks (TIA) or stroke.
The level of consciousness
Neurological physical examination
 Status of the sensory and motor systems
 evaluation of cranial nerves.
Cardiovascular system
Preop
cardiovascular
disturbances
• BP fluctuations, arrhythmias,MI
• Consequence of central
neurogenic effects on
myocardium
Pre-existing
cardiovascular
disease
• Hypertension,IHD,heart failure
• Valvular heart
disease,conduction
defects,PVD,DVT
Respiratory system
Respiratory • Aspiration pneumonia
complications • Neurogenic pulmonary
edema
Pre-existing
respiratory
disease
• COPD, asthma
• Restrictive lung disease,
OSA
Other Medical diseases
● Rheumatoid disease
● Indigestion, heartburn and reflux possibility of
hiatus hernia
● Diabetes
● Neuromuscular disorders
● Chronic renal failure
● Jaundice
Previous anaesthetics and
operations
Check the records of previous anaesthetics to
rule out or clarify problems such as difficulties
with intubation, allergy to drugs given or adverse
reactions (e.g. malignant hyperpyrexia)
Some patients may have been issued with a
‘Medic Alert’-type bracelet or similar device
giving details or a contact number
Preoperative medications
Antiepileptic medications
Dexamethasone/ Steroids
Antiplatelet agents or anticoagulants
Diuretics
Anti-DM, HT/IHD
Any other
Personal History
Smoking/Tobacco
Alcohol
Drugs
Pregnancy
Food, sleep, bowel/ bladder
Allergy- substance/ drug
Physical examination
 Neurological system
 Assessment of the neurological state:(GCS)
 Brief exam of the sensory and motor function
 Cranial nerve involvement: Occulomotor
Facial nerve
Glossopharyngeal
Vagus nerve
Physical examination
Cardiovascular system :
Arrhythmias
Heart failure
Hypertension
Valvular heart disease
Peripheral vascular disease
Physical examination
Respiratory system
Respiratory failure
 Impaired ventilation
 Collapse, consolidation, pleural effusion
 Additional or absent breath sounds
Physical examination
Musculoskeletal system
Any restriction of movement and deformity if a
patien has connective tissue disorders
 Cervical spine
 Temporo-mandibular joints
The airway
Look for
 Limitation of mouth opening
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Receding mandible
Position, number, and health of teeth
Size of the tongue
soft tissue swelling at the front of the neck
Deviation of the larynx or trachea
Limitations in flexion and extension of the
cervical spine
Simple bedside tests
 Mallampatti criteria: The patient, sitting upright, is asked to open their
mouth and maximally protrude their tongue.
Thyromental distance:

With the head fully extended on the neck,
the distance between the bony point of the chin and the prominence of
the thyroid cartilage is measured .A distance of <7cm suggests difficult
intubation.
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Calder test: The patient is asked to protrude the mandible as far as
possible. The lower incisors will lie either anterior to, aligned with, or posterior
to the upper incisors. The latter two suggest a reduced view at
laryngoscopy.
Wilson score:
 Increasing weight
 Reduction in head and neck movement
 Reduced mouth opening
 Presence of a receding mandible or
 Buck-teeth all predispose to increased difficulty with intubation
Investigations
 Investigation should only be ordered if the result would affect the
patient’s management
 Baseline investigations in patients with no evidence of concurrent
disease (ASA 1)
Investigations
Investigation should only be ordered if the result would affect the patient’s
management
Age >16 yrs
Additional investigations
 Urea and electrolytes: patients taking digoxin, diuretics, steroids,
and those with diabetes, renal disease, vomiting, diarrhoea
 Liver function tests: known hepatic disease, history of high alcohol
intake (>50 units/week), metastatic disease, or evidence of
malnutrition
 Blood sugar: diabetics, severe peripheral arterial disease, or taking
long-term steroids
 ECG: hypertensive, with symptoms or signs of ischaemic heart
disease, cardiac arrhythmia, or diabetic >40 years of age
 Chest X-ray: symptoms or signs of cardiac or respiratory
disease, or suspected or known malignancy, where thoracic
surgery is planned, or in those from areas of endemic
tuberculosis who have not had a chest X-ray in the last year
 Pulmonary function tests: dyspnoea on mild exertion, COPD,
or asthma. Measure peak expiratory flow rate (PEFR), forced
expiratory volume in 1 second (FEV1), and FVC
Patients who are dyspnoeic or cyanosed at rest, found to
have an FEV1 <60% predicted or are to have thoracic
surgeries, should also have arterial blood gas analysed while
breathing air
 Coagulation screen: anticoagulant therapy, history of
bleeding diatheses or history of liver disease or jaundice
 Sickle-cell screen (sickledex): family history of sickle-cell
disease or where ethnicity increases the risk of sickle-cell
disease, electrophoresis
 Cervical spine x-ray: rheumatoid arthritis, a history of major
trauma or surgery to the neck or when difficult intubation is
predicted
 Neuro-radiological images: CT scan, MRI and angiography
Valuable information pertaining to the size of the lesion,
location, possible vascularity and the surrounding structures
can be obtained
Echocardiography
 Left ventricular ejection fraction
 Contractility and ventricular wall motion abnormalities
 Post-MI ventricular function
 In valvular lesions, the degree of dysfunction
(regurgitation and/or stenosis) can be assessed
Medical referral
 Cardiovascular disease
● Untreated or poorly controlled hypertension or heart failure
● Symptomatic ischaemic heart disease, despite treatment (unstable
angina)
● Arrhythmias: uncontrolled atrial fibrillation, paroxysmal
supraventricular tachycardia and second and third degree heart
block
● Symptomatic or newly diagnosed valvular heart disease or
congenital heart disease
 Respiratory disease
● COPD, particularly if dyspnoeic at rest
● Bronchiectasis
● Asthmatics who are unstable, taking oral steroids or have an
FEV1<60% of predicted
 Endocrine disorders
● Insulin-dependent and non-insulin dependent diabetics who have
ketonuria, glycated haemogloblin (hba1c) >10% or a random
blood sugar >12 mmol/L
● Hypo or hyperthyroidism symptomatic on current treatment
● Cushing’s or addison’s disease
● Hypopituitarism
 Renal disease
● Chronic renal failure
● Patients undergoing renal replacement therapy
 Haematological disorders
● Bleeding diatheses, for example- haemophilia, thrombocytopenia
● Therapeutic anticoagulation
● Haemoglobinopathies
● Polycythaemia
● Haemolytic anaemias
● Leukaemias
Pre-op concerns in specific surgeries
 Supratentorial tumors :
 Documentation of altered level of consciousness, S/S
of raised ICP
 Sensory or motor deficits and seizures is essential
 Review the CT and MRI imaging
 Evaluate hydration and volume status
 Preoperative management of the electrolyte
imbalances
Signs and symptoms of raised
ICT
Apnoea,
Dilated and unreactive pupil,
C/L hemiplegia,
Decreased consciousness,
Bradycardia
Nausea, vomiting, headache,
altered mental status,
hypertension,
Visual disturbances,
papilloedema, U/L pupillary
dilatation
 Awake craniotomy for tumor surgery:
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There are different techniques of awake craniotomy, such as asleepawake-asleep or monitored anesthesia care with conscious sedation
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The degree of anxiousness, tolerance to pain and the ability to cooperate
are factors to be noted during the preoperative assessment
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With each technique, airway assessment is of extreme importance,
predictors of difficult airway and factors that can favour upper airway
obstruction such as obesity and OSA should be noted
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Preparation of the patient includes psychological preparation, reassurance
and educating the patient regarding the events of the procedure
including various tests during mapping
 Pituitary tumors:

Acromegaly :
Large body mass as well as an unpredictable and difficult
airway and OSA
Detailed evaluation of the cardiac system
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Cushing’s disease : Hypertension, glucose intolerance, myelopathy,
osteoporosis, obesity, and OSA
Obesity, moon facieses, buffalo hump and OSA may
be associated with a difficult airway

Sodium imbalances may indicate posterior pituitary dysfunction in the form
of diabetes insipidus or SIADH
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Preoperative hypopituitarism : should receive steroid and hormone
replacement therapy perioperatively
 Posterior fossa surgery :
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Preoperative documentation of loss of gag reflex, laryngeal nerve
dysfunction, and altered states of consciousness
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Positioning : Park bench, prone or sitting
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Lateral and prone position: increased risk for peripheral nerve injury, eye
injury and postoperative blindness
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Sitting position: increased risks of quadriplegia, paraplegia, facial oedema,
macroglossia, and venous air embolism (VAE). The incidence of VAE is high
(39%) in the sitting position
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Preoperatively rule out the presence of an intracardiac ( persistent foramen
ovale) or an intrapulmonary shunt if proposed position of patient is sitting
 Cerebral aneurysm:
 SAH: multisystem involvement
 Intracranial complications-rebleeding,vasospasm,hydrocephalus,clot,
seizure
 Cardiac complications- abnormalities in rhythm, elevated cardiac
enzymes, myocardial dysfunction
 Respiratory complications - neurogenic pulmonary edema
 Electrolyte abnormalities - hyponatremia, hypokalemia,
hypomagnesaemia and hypocalcaemia
 Cerebral vasospasm, consider treatment with “Triple H therapy”
 Most patients are started on calcium blocker, usually nimodipine, and
this should be continued preoperatively
 Cerebral arteriovenous malformation
 Perioperative blood pressure management
 Induced hypotension is frequently used
intraoperatively to reduce bleeding and
postoperatively strict control of the blood pressure is
often needed to minimize complications such as
bleeding and hyperperfusion syndrome
 Availability of blood for transfusion is essential, as
blood loss can be substantial during the surgical
resection
 Interventinal neuroradiology(coiling and stenting of aneurysms,
embolisation of AVM, arteriovenous fistula, and vascular tumors, and
stenting of carotid artery stenosis )
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Assessment and preparation of these patients also involves ensuring that
they are suitable for radiological procedures.
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Pregnancy
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Renal function
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H/o allergy to contrast dyes, protamine sulphate

Coagulation status

Remote location

Manipulation of hemodynamics includes induced hypotension and even
the use of adenosine to stop the heart during delivery of the embolic
materials
 Functional neurosurgery: (Deep Brain Stimulators)

Preferred technique local anesthesia with monitored care

Elderly patients with multiple comorbidities

Patients should be assessed for their ability to cooperate and ability to
tolerate the various stages of this surgery which include placement of a
head frame, preoperative imaging, and the insertion and testing of the DBS

Assessment of the airway

Medications used to treat motor symptoms are often withheld on the
morning of the surgery

Premedications such as opiods, benzodiazepines, and other sedatives can
interfere with the interpretation of tremor and hence is avoided. The
decision to preoperatively withhold anti parkinson drugs may result in a
patient with severe symptoms of rigidity or tremors
 Epilepsy surgery (insertion of cortical electrodes for mapping and
activation of the epileptogenic focus, and craniotomy for resection
of the focus that may be with awake craniotomy or under general
anesthesia)
 Administration of anticonvulsant agents prior to surgery is done in
consultation with the neurologist and surgeon
 Specific concerns of patients with epilepsy include the
accompanying medical problems such as psychiatric disorders,
neurofibromatosis, and multiple endocrine adenomatosis.
 Specific anesthetic considerations include adverse effects of
antiepileptic drugs such as confusion, sedation, ataxia and nausea
and vomiting, induction of liver enzymes
Risks of having anaesthesia? The culprits
Human
errors
Adverse
drug
reactions
Drug
interactions
Complications:
Minor
Major
Failed iv
access
Aspiration
Cut lip,damage to
teeth,caps,crowns
Hypoxic brain
damage
Sore throat
MI,CVA
PONV
Nerve injury,renal
failure
Retention of
urine
Death
ASA physical status scale
Classification of operation
 National confidential enquiry into perioperative outcome and death
(NCEPOD) has identified four categories:
1. Immediate: to save life, limb, organ, resuscitation goes
hand in hand
2. Urgent: surgery normally takes place when resuscitation
is complete
3. Expedited: stable patient requiring early intervention.
Condition not an immediate threat to life, limb, or organ
4. Elective: surgery planned and booked in advance of
admission to hospital
Obtaining informed consent
 What is consent?
 Consent is an agreement by the patient to undergo a specific
procedure.
 The pre-anaesthetic assessment should include confirmation with the
patient, the patient’s guardian in the case of children below 18 years or
the intellectually challenged, of the nature of the anaesthetic
procedure and his / her consent for anaesthesia
 Documentation
 A written summary of the pre-anaesthetic assessment, orders or
arrangements should be explicitly and legibly documented in the
patient’s anaesthetic record.
 What about an unconscious patient?
thank you