Anaesthetics - bits Flashcards
What is malignant hyperthermia? How does it present? How is it managed?
Presentation:
- Tachycardia
- Pyrexia
- Stiffening of arms etc..
Causes:
- Suxamethonium (depolarising muscle relaxant) or volatile gases e.g. sevo- des- and isofluorane
Management:
- Dantrolene
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What is the ASA grading system?
American Society of Anaesthesia - grades severity of disease and used to assess whether patient is fit for anaesthesia:
1 - normal healthy patient, without clinically important comorbidity/PMH
2 - mild systemic disease
3 - severe systemic disease, some limitation of ADLs
4 - severe systemic disease, marked limitation in ADLs, constant threat to life
5 - moribund patient, not expected to live for >24hrs without the operation
What is the mallampati scoring system? What other factors are relevant to consider?
Used to predict the ease of ET tube insertion
Assesses anatomy of oral cavity and what can be visualised on the normal opening of mouth:
1 - soft palate, uvula, fauces, pillars visible
2- soft palate, major part of uvula, fauces visible
3- soft palate, base of uvula visible
4 - only hard palate visible
Other things to check:
- Neck mobility/pathology
- BMI (higher = trickier)
- Thyromental distance (>7cm may be trickier)
- Hx difficult intubation
- OSA PMH or symptoms
What information is covered on a preoperative WHO checklist?
Before anaesthesia:
- Patient identity confirmed + site + procedure + consented
- Site marked
- Anaesthesia machine and medication check
- Pulse oximeter on and functioning
- Allergies
- Difficult airway or aspiration risk
- Anticipated blood loss >500ml
Before skin incision:
- Confirm all team members introduced by name and role
- Confirm patient identification, procedure and location of incision
- Antibiotic prophylaxis given within last 60mins
- Anticipated critical events = critical/non-routine steps, how long, anticipated blood loss ; any specific patient concerns ; sterility confirmed, equipment issues
- Is essential imaging displayed
Before patient leaves:
- Name of procedure
- Completion of instrument, sponge and needle counts
- Specimens labelled
- Equipment problems to address
- Key concerns for recovery and post-op management
What things to anaesthetists need to check with their patients before anaesthesia?
Patient details
Medications
- Esp anticoag/plts, diabetic meds, HTN meds
Significant PMHx + severity grading (resp, cardio, GI, renal/endo, neuro/msk, haem)
- Incl. COPD, OSA, functional status, HTN, DM, GORD, spinal injuries
Allergies
Anaesthetic Hx
Airway exam (malampatti, thyromental, mouth opening etc)
Dentition (caps/crowns, dentures)
Procedure to be done + consent
What are the rules re. fasting pre-op?
Food/milk containing drinks
- up to 6hrs before induction
Water/’clear fluids’
- up to 2hrs before induction
What are the key rules re. stopping anticoagulants pre-op?
Warfarin:
- Stop 6 days prior to surgery
- Bridge with LMWH
- Check INR +/- vit K reversal if emergency
Unfractioned heparin:
- Stop 4hrs before surgery
LMWH:
- Prophylactic dose - stop 12hrs before
- Treatment dose - stop 24hrs before
NOACs:
- Apixaban = 48hrs
- Dabigatran = 48hrs
- Prophylactic rivarox = 18hrs
- Treatment rivarox = 48hrs
What are the key rules re. stopping antiplatelets pre-op?
Aspirin, dipyridamole and NSAIDs
- Continue as normal unless deteriorating renal function or otherwise specified
Clopidogrel
- Stop 7days prior (as irreversible platelet inhibition)
What are the key rules re. stopping antihypertensives and antiarrhythmics pre-op?
ACE/ARBs:
- Withhold on morning of surgery, unless otherwise specified
Diuretics:
- Withhold
BB’s:
- Continue as normal
Digoxin:
- Will
What are the key rules re. other medications pre-op?
Diabetic medications:
- Oral hypoglycaemics = omit on day of surgery
- May need intraoperative sliding scale insulin-dextrose, if missing multiple meals
- Often need to be listed first to minimise fasting times
Steroids:
- Taking anything >5mg PO pred will need supplementary during the perioperative period
OCP:
- Ideally stop to reduce VTE risk
Antidepressants:
- MAO-i’s = inform anaesthetist
- Li = check levels + u+e + TFT prior to surgery and stop 24hrs before
Herbal medications:
- Stop 2wks prior
What drugs do you continue to give in the perioperative period?
Antiepileptics, Parkinson’s, asthma drugs/inhalers, those which decrease gastric acid, thyroid, immunosuppressants
May be taken during the NBM period with a small amount of water
