DPD: Preoperative assessment of the surgical patient Flashcards
Why perform a preoperative assessment?
Identify + modify risks associated with: airway, anaesthetic, surgery, post operative
May require further special tests/ interventions pre-op
Make decisions on medication E.g. Aspirin/ Metformin
Give advice on fasting
Make decisions on post-op care E.g. ICU/ HDU
When is a pre-op assessment performed?
2-4 weeks before surgery:
Long enough to arrange Ix
Soon enough to avoid interim medical problems
What important additional information must be gleaned in addition to a normal patient history?
Previous surgeries/ anaesthetics
Any problems e.g. airway/ intubation problems, reaction to drugs, N+V
Smoking/ ETOH
FHx of problems with anaesthetics e.g. malignant hyperpyrexia
Describe the ASA grading system of patients
I: Healthy patient, uncompromised
II: Mild systemic disease e.g. hypothyroidism, well controlled HTN or DM
III: Moderate systemic disease e.g. ESKD requiring dialysis, uncontrolled HTN or DM
IV: Severe systemic disease, constant threat to life
What is involved in an airway assessment pre-operatively?
Assess neck extension/ flexion: pain/ difficulty/ danger?
Mouth opening: how far can you open your mouth?
Mallampati score
Jaw protrusion: can they stick their bottom teeth infront of their top teeth? (needed for laryngoscope + tube insertion)
What drugs may need to be sustained, swapped or stopped before surgery?
Blood thinners: anticoagulants/ antiplatelets
Diabetes drugs: metformin, insulin
Antihypertensives
Why is a nil by mouth policy in place? What are the guidelines for fasting before surgery?
Reduce aspiration risk
NBM: 2 hours, Except for 30mls water with tablets
Clear fluids: 2 hours before
Solid food: 6 hours before
What special consideration must be planned for certain diabetic patients?
IV Insulin infusion
What does POSSUM use? Why is it useful?
Patient physiological parameters + operative variables
Calculates mortality + morbidity risk
Informs risk discussion, extra requirements in + post surgery
How do you optimise and control a diabetic for surgery?
Measure glycosylated Hb
In IDDM: insulin sliding scale
How do you optimise and control a patient with HTN for surgery?
Measure BP
Stay within 20% of normal BP
How do you optimise and control a patient with IHD for surgery?
ECG/ symptoms
BP + HR control
How do you optimise and control a patient on anticoagulants for surgery?
Reason for anticoagulants?
AF: stop
Heart valve: continue
Which 3 factors influence whether a surgery can be a day surgery?
Social: consent, carer, home setup
Medical: fitness, stable chronic
Surgical: complication risks, controllable post-op symptoms, mobility
In which patients should you perform further pre-op investigations?
Blood anomalies: anaemia, renal dysfunction
What must be included in prescription of opioids? e.g. morphine
Dose
Form
Strength (where appropriate)
Total quantity or dosage units of the preparation in words + figures
For instalment prescriptions, specify the instalment amount + instalment interval
What are the 2 types of spontaneous ventilation?
Unassisted: pressure gradient generated only by respiratory muscles
Assisted: ventilator acts as a pressure generator in series with the respiratory muscles + work is shared by the muscles + the machine
What is natural spontaneous ventilation?
Respiratory apparatus pulls rib cage open, creating a negative inspiratory pressure.
Leads to lung expansion + the pulling of air into the alveoli allowing gas exchange.
What is positive pressure ventilation?
Compressed air enters at the alveolar level for gas exchange.
What is the main difference between spontaneous ventilation and mechanical ventilation?
Spontaneous: air pulled into the lungs
Mechanical: air pushed into the lungs
What is a Guedel (oropharyngeal) airway? Why is it used?
Airway adjunct
Prevents tongue covering epiglottis in patients with reduced GCS
O2 mask or bag mask ventilation can be applied over the top if needed
What is a bag-mask-valve? What do they do? Who are they used in?
Self-inflating resuscitation device
Provide positive pressure ventilation to patients not breathing.
Used in apnoeic patients
What is an endotracheal tube? What are the indications for use?
Tube forms a definitive airway, attached to bag/ machine
Inadequate ventilation/oxygenation
Maintain a patient’s airway in surgery
What is an Igel/ supraglottic device? When is it used?
Tube which sits over top of larynx
Provides some aspiration protection but doesn’t fully secure the airway
Airway protection during surgery
Cardiac arrest
