pre-operative evaluation and preparation (prior to procedure under general anesthesia)
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Aishah Awatif Haziq. Pre-operative evaluation and preparation (prior to procedure under general anesthesia). Introduction . Anaesthesia = absence of all sensation Analgesia = absence of pain - PowerPoint PPT PresentationTRANSCRIPT
PRE-OPERATIVE EVALUATION AND PREPARATION (PRIOR
TO PROCEDURE UNDER GENERAL ANESTHESIA)
AishahAwatifHaziq
Introduction Anaesthesia = absence of all sensation Analgesia = absence of pain General anaesthesia = a state where all
sensation is lost and the patient is rendered unconscious by drugs.
GA should be performed by qualified anasthetists in a hospital setting with access to appropriate medical support.
Assessment of risk Patient should be made as fit as
possible for the operation. The anticipated benefit should outweigh
the anesthetic and surgical risks involved.
Overall mortality rate ≈ 1 in 100 000 Surgical mortality ≈ 1 in 1000
Factors contribute to this mortality:Poor preoperative assessmentInadequate supervision and monitoring in
the intraoperative periodInadequate postoperative care
Aims of Pre-operative evaluation and preparation To provide diagnostic & prognostic information. To ensure the patient understands the nature, aim,
and expected outcome of surgery. To relieve anxiety and pain. Ensure that the right patient gets the right surgery. Get informed consent. Assess/balance risks of anaesthesia ans
maximize fitness. Check anaesthesia/analgesia type with
anesthesia.
Preoperative assessment and premedication
History Past medical history:
AsthmaDiabetesTuberculosisSeizuresChronic organ dysfunctionHIV infectionDrug allergyDVTPost-operative nausea and vomiting
Drug history Drug interactions
Anticoagulant might be contraindicated to spinal, epidural or other regional techniques
Anticonvulsants might increase the requirements for anasthetic agents, enflurane should be avoided as it might precipitate seizures
Beta-blockers – negative ionotropic effect – hypotension
Corticosteroids – extra cover might be needed
Diuretics – might have hypokalaemiaInsulin – careful monitoring of plasma
glucoseAntibiotics: tetracycline and neomycin may ↑
neuromuscular blockade.
Social history Ceasing smoking 12h before surgery
can improve the oxygen carrying capacity of the blood.
Excessive alcohol – hepatic and cardiac damage
Family history Hereditary traits:
Haemophilia PorphyriaCholinesterase abnormalities – prolongation
of muscle relaxants such as suxamethonium
Physical examination Assess cardiorespiratory system, exercise
tolerance, existing illness, drugs, and allergies. Is the neck unstable (eg; arthritis complicating
intubation?) Assess past history of; MI, diabetes, asthma,
hypertension, rheumatic fever, epilepsy, jaundice.
Assess any specific risk, eg is the patient pregnant? Is the neck/jaw immobile and teeth stable (intubation risk)?
Has there been previous anaesthesia? Were there any complications (eg
nausea, DVT)? Is DVT/PE prophylaxis needed?
Per-op investigation of elective patients
Indications of preoperative investigations
Full blood countanaemiafemales post menarchecardiopulmonary diseasepossible haematological pathology, e.g.haemoglobinopathieslikelihood of significant intraoperative blood losshistory of anticoagulantschronic diseases such as rheumatoid disease
Clotting screenliver diseaseanticoagulant drugs or a history of bleeding orbruisingkidney diseasemajor surgery
Urea and electrolyte concentrationsmajor surgery >40 yearskidney diseasediabetes mellitisdigoxin, diuretics, corticosteroids, lithiumhistory of diarrhoea and vomiting
Liver function tests: these will be carried out when thereis any suspicion of liver disease
ECG>40 years asymptomatic male or >50 years
asymptomatic femalehistory of myocardial infarction or other heart or
vascular disease<40 years with risk factors e.g. hyperlipidaemia,
diabetes mellitus, smoking, obesity, hypertension and cardiac medication
Chest radiographybreathlessness on mild exertionsuspected malignancy, tuberculosis or chest infectionthoracic surgery
American Society of Anesthesiologists (ASA) classification
Class I Normally healthy
Class II Mild systemic disease
Class III Severe systemic disease that limits activity but is not incapacitating
Class IV Incapacitating systemic disease which poses a constant threat to life
Class V Moribund: not expected to survive 24h even with operation
Pre-op therapy Pt with respiratory disease –
physiotherapy or bronchodilator therapy
Infective endocarditis – prophylactic antibiotic
Hypertension – adjustment of drug therapy to obtain optimal control (diastolic pressure below 110 mmHg)
Postponement of surgery Pt with acute upper resp tract infection Cardiac/endocrine diseases that are not
yet under optimal control Elective surgery should not be undertaken
unless:Pt has fasted for 6h for solid food, Infant
formula or other milk4h for breast milk2h for clear non-particulate and non-
carbonated fluids
Pre-medication benzodiazepines – anxiolysis, anterograde
amnesia Anticholinergic drug – reduce excessive
secretions in the airway Antiemetic Antihistamine Metoclopramide - enhance gastric emptying Sodium citrate, H2 blockers, proton pump
inhibitor – reduce gastric acidity
Preparation for anesthesia Fast patient.
Nil by mouth ≥ 2h pre-op for clear fluid and ≥ 6h for solids
Is there any bowel or skin preparation needed, or prophylactic antibiotic?
Start DVT prophylaxis as indicated, eg: graduated compression stockings + heparin 5000U sc 2h pre-op, then every 8-12h sc for 7d or until ambulant.
Write up the pre-meds; book any pre-, intra-, or post-operative x-rays or frozen sections. Book post-op physiotherapy.
If needed, catheterize and insert Ryle’s tube before induction. These can reduce organ bulk, making it easier to operate in the abdomen.