PreOp Assessment Flashcards
What are the 3 steps to pre op assessment
History
Examination
Investigation
List 6 important components of the preop hx
- age and gender
- indication for surgery
- surgical/anesthetic surgery
- familial hx
- medications & allergies
- past medical hx
What aspect of the past surgical/Anesthetic hx is important?
- past intubation
- PONV
- anaesthesia complications
- previous anaesthetics
What details are important in the family hx
- anaesthetic reactions
- MH (malignant hyperthermia)
- pseudocholinesterase deficiency
It is good to ask system based medical histories. What are you looking for in your Neuro hx?
TIA/Strokes
Raised ICP
Spinal Disease
Aneurysm
NMJ problems
It is good to ask system based medical histories. What are you looking for in your CVS hx?
angina/cad
MI
CHF
HTN
Valvular disease
Dysrythmias
PVD
It is good to ask system based medical histories. What are you looking for in your Respi hx?
Smoking
Asthma
COPD
URTI
apnea
It is good to ask system based medical histories. What are you looking for in your GI hx?
GERD
Liver disease
NPO status
It is good to ask system based medical histories. What are you looking for in your Renal hx?
Chronic Renal Failure
Dialysis
It is good to ask system based medical histories. What are you looking for in your MSK hx?
Arthralgia
Cervical spinal pathology
Cervical spine instability
It is good to ask system based medical histories. What are you looking for in your Endocrine hx?
DM
Thyroid disorders
Adrenal Disorders
It is good to ask system based medical histories. List some other important information not mentioned in the previous systems?
Pregnancy
Ethanol/ recreational drug use
Morbid obesity
List 8 aspects of the physical exam for pre op anaes
- weight, height, BP, HR, RR, O2 sat
- CNS, CVS, RESPI
- assess nutrition, hydration, mental status
- Airway assessment & Ventilation
- Tongue size
- Dentition, Dental appliances/ prosthetic caps, chipped/teeth
- Nasal passage latency
- examination of anatomical sites relevant to lines and blocks
How do you evaluate a difficult airway?
L - look (obesity, facial/dental Abn. beard, neck)
E - evaluate 3,3,2 rule
M- Mallampati score
O- Obstruction
N- Neck mobility
How do you assess difficult ventilation anesthesia ?
BONES
B- beard
O- obesity
N- no teeth
E- elderly (>55)
S- Snoring hx (sleep apnea)
What is the 3-3-2 rule?
1) 3 of the patients own finger can be placed between incisors
2) 3 fingers along the floor of the mandible (between mentum and hyoid)
3) 2 fingers in the superior laryngeal notch (thyroid- mouth distance)
Full view of uvula (body and base of uvula) and Tonsillar pillars describes what Mallampati Score?
1
View of the body and base of the uvula, with partial view of the tonsillar pillars describes what Mallampati score
II
View of the base of the uvula is described as what Mallampati score
III
View of the hard palate with no other visible structures is described as what Mallampati score
IV
What grading system is used for Laryngeal View?
Cormack- Lehane Classification
Describe Grade 1 Cormack- Lehane Classification
All Laryngeal structures revealed
Describe Grade 2A Cormack- Lehane
Partial view of the glottis
Describe Grade 2B Cormack- Lehane
Only the arytenoids visible
Describe Grade 3 Cormack- Lehane
Larynx is concealed only epiglottis seen
Describe Grade 4 Cormack- Lehane
Neither epiglottis nor glottis seen
What are three other scoring systems used to assess difficult airways
Thyromental distance
Calder test
Wilson Score
List 5 factors of the Wilson Score System
(Wilson Understands Joy Ride Baking)
Weight
Upper cervical spine mobility
Jaw movement
Receding mandible
Buck teeth
Describe the ASA classification system
perioperative clinicians a simple categorization of a patient’s physiological status that can help predict operative risk.
I A normal healthy patient
II A patient with mild systemic disease
III A patient with severe systemic disease
IV A patient with severe systemic disease that is a constant threat to life
V A moribund patient who is not expected to survive sans surgical procedure
VI A declared brain dead patient whose organs are being removed for donor purposes
The addition of E indicates emergency surgery
Which patient counts as a high risk patient
Those who must be seen by an anesthesiologist in their pre operative clinic
Which patients are usually seen by anaesthesthetists in clinic
Patients at or above ASA 3
Prior or anticipated difficulties with anaesthesia
Patients having complex procedures performed
What is the target BP reading that you should aim for when dealing with hypertensive patients in anesthesia
<180mmHg SBP and <110mmHg DBP
Which antihypertensives should be avoided on the day of surgery and why
Ace inhibitors and ARBs
Due to the increased risk of refractory hypotension
How long should a post MI patient wait before surgery
60 days
What is the glycaemic target in critical patients with DM
<10 mmol/L
What is the glycaemic target in stable patients with DM
<7.8 mmol/L
True or False
Oral anti diabetic medications should be given on the day of surgery
False
Why are URTI and poorly controlled asthma absolute contraindications for Anaesthesia
It can increase the risk of bronchospasm
What is the minimum time that you can have a heavy meal before surgery?
8hrs
What is the minimum time that you can have a light meal/ cow’s milk/ infant formula before surgery?
6hrs
What is the minimum time that you can have breast milk before surgery?
4hrs
What is the minimum time that you can have non-alcoholic clear fluids before surgery?
2hrs
What are the benefits of allowing clear liquids up to 2hours pre-op?
Less patient thirst and hunger
Lower risk of aspiration
Define premedication
The administration of medication before a treatment or procedure
What are the 6 A’s of premedication?
Anxiolysis
Amnesia
Antiemetic
Antacid
Anti- autonomic
Analgesia
Which drug class is administered for anxiolysis and when?
Benzodiazepines
(45-90mins before)
Which drug class is administered to induce amnesia?
Benzodiazepines
What is the Moa of benzodiazepines
Benzodiazepines facilitate the binding of inhibitory neurotransmitter GABA at various GABA receptors in the CNS
GABA functions to reduce neuronal excitability by inhibiting nerve transmission
Benzodiazepines can be classified as long acting, intermediate acting and short acting
List an example of each
LA: Diazepam (Valium) 1-3 days
SA: Midazolam (Versed) 3-8 hrs
IA: Alprazolam (Xanax)/ Lorazepam (Ativan) 11-20hrs
Which drug classes can be administered as antiemetics ?
5-HT antagonist
Dopamine Antagonist
Antihistaminic
Anticholinergic
Describe the moa of 5-HT antagonists (selective serotonin antagonists) as antiemetics
Vomiting is controlled by the vomiting center in the brain, which is activated by triggers such as strong smell, thoughts and motion.
The cells that line the gastrointestinal tract release serotonin (a chemical messenger responsible for transmitting vomiting signals) when they are damaged.
This serotonin binds to the serotonin receptors present on the nerves that transmit impulses to the vomiting center located in the brain, which in turn activates the vomit reflex.
Antiemetic 5-HT3 antagonists block the serotonin both peripherally, on gastrointestinal vagal nerve terminals, and centrally in the chemoreceptor trigger zone; this blockade results in powerful antiemetic effects.
How do Antihistaminic agents function as antiemetics?
Histamine is a key molecule for transmitting stimuli from the inner ear to the brain during vomiting due to motion sickness
They block H1 receptors
What neurotransmitters are involved in vomiting?
acetylcholine,
dopamine,
histamine (H1 receptor),
serotonin (5-HT3 receptor)
List 1 Dopamine antagonist
Metoclopromide (Reglan)
List 1 selective serotonin antagonist
Ondansetron
List 1 Antihistaminic drug
Diphenhydramine (Benadryl)
List 3 antacid drug classes used
H2 Blocker
PPI
Sodium citrate
Describe the moa of H2 blockers
H2RAs decrease gastric acid secretion by reversibly binding to histamine H2 receptors located on gastric parietal cells, thereby inhibiting the binding and activity of the endogenous ligand histamine.
Give one example of an h2 blocker
RANITIDINE
Famotidine
Describe the moa of PPI
Ultimately, PPIs function to decrease acid secretion in the stomach. The proximal small bowel absorbs these drugs, and once in circulation, affect the parietal cells of the stomach. The parietal cells contain the H+/K+ ATPase enzyme, the proton pump, that PPIs block. This enzyme serves as the final step of acid secretion into the stomach
List some PPIs
Omeprazole
Esomeprazole
Pantaprazole
How does sodium citrate act as an antacid
It acts by neutralizing acid in the stomach and urine, raising the pH
List two groups of Antiautonomic drugs
Anticholinergics
Beta Blockers
List 2 groups of Anticholinergic drugs
Antisialogogue
Antivagolytic
List some Anticholinergic d’agents
Atropine IV/IM/SC
Glycopyrrolate - 4mcg/kg IM
List some Analgesics
Opioids
- Morphine
- fentanyl
List 5 contraindications to anaesthesia
No consent
Allergy Hypersensitivity
Respiratory Depression
Cardiovascular Issue
Liver or Kidney Dysfunction
Pregnancy and Breastfeeding
PACU (Post Anaesthesia Care Unit)
What is post anaesthesia care?
Steps taken after the completion of a surgical procedure to manage a patient who has received general anaesthesia or sedation
What are the 4 goals of Post Anesthesia Care
To reduce postoperative adverse events
To provide a uniform assessment of recovery
To improve post anaesthetics quality of life
To streamline postoperative care and discharge criteria
What are 4 reasons that patients should be given oxygen in the postoperative period?
To counter effects of diffusion hypoxia when nitrous oxide is used
Compensate for hypoventilation
Compensate for V/Q mismatch
Meet the increased oxygen demand when shivering
List 2 techniques of administration of postoperative analgesia
Patient Controlled Analgesia (PCA)
Regional Analgesics Technique (nerve block, epidural analgesia)
List 8 criteria for discharge of patients from the post anaesthesia care unit
Fully conscious - able to maintain airway
CVS stable
Pain and PONV controlled
Temperature acceptable
IV Cannulae patent (flushed to remove residual anaesthesia)
All surgical drains and catheters checked
All health records and medical notes completed