Anaesthesia Flashcards
What are 5 ways to confirm placement of an endotracheal tube?
End tidal CO2 Direct visualization Misting in tube Auscultation (both sides!) Symmetrical rise and fall of chest?
What is the acronym for the preparation to intubate?
MS MAiD
Machine
Suction
Monitor
Airway
IV
Drugs
How do you decide if a patient needs further cardiac work up before an operation
Assess risk factors, then consider METs; if able to tolerate 4 or more (ie mild-moderate activity) can proceed w/o workup
What are the risk factors for PONV?
Female gender
Younger patient
Non smoker.
Ocular/vestibular and Tyne procedures
What are some options to help with PONV?
Dexamethasone (0.1 mg / kg day)
Odansetron (4mg)
Haldol (1-2mg)
Benzos or propofol, if refractory
What do you want to check before you extubate?
Patient must be hemodynamically stable
Properly oxygenating
Breathing on their own
Eyes open / signs of awareness
What would explain a sudden drop in end-tidal CO2
Low cardiac output (check BP)
What are the risk factors for malignant hyperthermia?
FH of malignant hyperthermia or previous hx of it (ie mutation to ryanodine receptors)
What are early signs of Malignant hyperthermia
Sudden increase in end tidal CO2, muscle rigidity, mixed metabolic and resp acidosis, tachycardia, tachypnea, unstable BP, masséter spasm
What are late signs of malignant hyperthermia?
Sudden increase in body temperature, CK above 10,000 , hyperkalemia >6, DIC
What elements of the ROS should be emphasized in the preop assessment?
CV Resp Renal dysfunction Neuro Endocrine Coagulopathy Cancer Msk affecting esp c spine
What elements are important to elicit on preop history?
Previous hx of any issues with anaesthesia or FH of issues with anaesthesia, difficult intubation, difficult IV access, post op n/v
What are the major changes to the maternal physiology that impact pregnancy?
Delayed gastric emptying ( increased risk of aspiration )
Aortocaval compression
Decreased FRC
Increased mucous secretions, more difficult airway (controvertial)
What are the nonpharm options for control of pain in labour?
Tens, hydrotherapy, hypnosis, breathing exercises, prenatal classes.
What pharmacological management is available to labouring patients?
Nitrous oxide
Opioids
Neuraxial anaesthesia (spinal, epidural)
Pudendal, paracervical blocks
What are some maternal potential side effects to opioid anaesthesia in labour?
Pruritis, resp depression, nausea, constipation, venodilation
What are potential fetal effects of opioid anaesthesia in labour?
Resp depression, reduced variability beat to beat in FHR, sedation
What is the difference between spinal and epidural blocks? (Location, onset, side effects)
Location: epidural is in epidural space, spinal is into the canal below L2/L3 (below the conus medullaris)
Onset - epidural takes 15 min, spinal much quicker (within 5 minutes)
Side effects: greater risk of hypotension and headache with epidural.
What are the contraindications to obstetrical anaesthesia?
Severe hypotension or hemodynamic instability Infection or sepsis Coagulopathy Low cardiac output Increased ICP
What are common complications for spinal / epidural anaesthesia? (6)
Hypotension w w/o bradycardia Fetal bradycardia Headache Ineffective block Pruritis N/V
What are the typical onset, distribution and associated symptoms of postural puncture headache? How is the pain affected by positioning?
Onset: 24-48hrs post puncture
Distribution: Fronto-occipital
Associated symptoms include tinnitus and diplopia.
Positioning: Worse upright and better supine
What are the management options for post-puncture headache? What can you do if pharm & non pharm options fail?
Encourage bed-rest & supine positioning + adequate hydration.
Pharmacological management includes caffeine or analgesics including acetaminophen, NSAIDs, opioids.
Can offer epidural blood patch if above options don’t work.
What are the triggers (3) of malignant hyperthermia?
Inhalantional agents (sevoflurane etc.)
Succinylcholine
Phenothiazines
What underlying patient conditions must you consider on your differential when you are worried about potential malignant hyperthermia (6)?
diabetic coma, hyperthyroidism, neuroleptic malignant syndrome, muscular dystrophies, myotonia, osteogenesis imperfecta
What acquired (5) and intraoperative (4) issues can be confused with malignant hyperthermia?
Acquired: anaphylaxis, heat stroke, transfusion reaction, alcohol withdrawal, sepsis
Intraop issues: heat transfer imbalance, equipment malfunction, hypoventilation, insufficient anaesthesia.
How do you manage malignant hyperthermia?
Discontinue any anaesthetic agents ASAP
Hyperventilate 100% O2 with as high a flow as possible
Dantrolene (2.5mg/kg IV q10min up to 10 mg/kg)
Bicarb (for hyperkalemia)
Active cooling
Monitor urine + vitals
Order CK, ABG, Electrolytes, INR/PTT, fibrinogen.
What is plasma cholinesterase deficiency?
Enzyme activity that degrades succinylcholine is low, so delayed awakening following anaesthesia with succinylcholine.
What is the acronym for causes of difficult bag-mask ventilation?`
ROMAN Radiation or restriction Obstruction (think obesity and OSA) Mask (beard) or Mallampati Age >55 No teeth
What are the 5 elements you want to evaluate in the airway assessment?
Inspect externally for trauma, congenital deformities, neck mass or retrognathia. Listen for hoarseness or stridor.
332 rule (3-finger mouth opening, 3 finger hyoid mentum distance, 2 finger thyroid/thyroid cartilage distance
Mallampati score (stick tongue out)
Obesity/OSA
Neck mobility
What are the 3 major causes of airway emergency?
- inadequate ventilation
- esophageal intubation
- difficult tracheal intubation (prolonged apnea, trauma)
Under what circumstances is it appropriate to order pre-op CBC?
age >65 w major surgery
or large expected blood loss
or neuraxial anaesthesia (want to establish PLT count)
Under what circumstances do you assess renal function pre-op?
Age >50, intermediate/high risk surgery. Risk of hypotension, or use of nephrotoxic meds
When do you order pre-op ECG?
Known heart disesase or PAD esp if patients symptomatic
When do you order pre-op CXR?
> 50 + AAA repair / thoracic surgery or cardiopulmonary disease
BMI >40
What are the 6 levels of the ASA classification
- healthy, no comorbidities
- mild systemic disease or pregnancy
- moderate systemic disease with some functional limitation
- severe disease that is a threat to life (end-stage conditions)
- not expected to survive w/o operation
- functionally brain-dead organ donor
What should you advise patients in terms of NPO?
Nothing heavy for at least 8 hrs pre op
6 hrs light meal, low protein/fat
4 hours breast milk
2 hours clear fluids.
How do you manage T2DM perioperatively?
check pre/post sugars
hold oral meds on day of operation
Treat with insulin as needed
Resume oral meds once eating wel
What cardiac medications should be held on the day of surgery?
ACE-I or ARB (case-by-case), Diuretics
How do you change steroid therapy perioperatively?
Continue unless >3weeks therapy, then consider dose modification as appropriate.
What medications that affect hemostasis should be stopped before surgery?
ASA (discuss with cardiology if need be), clopidogrel, ticagrelor, prasugrel or ticlodipine, warfarin, dabigatran, or rivaroxibran.
For ASA, stop 7 days, warfarin hold 5 days, oral anticoagulants can be held 2-3days preop
What psychiatric medications should be held preop?
MAOIs (need discussion with psychiatry and MAOI safe technique), antipsychotics (QTc prolongation, need ECG), psychotimulants
What rheumatological agents need to be held before surgery?
Everything except hydroxychloroquine and methotrexate
What herbal supplements should be discontinued prior to surgery?
ephedra (ma huang), garlic, ginko, ginseng, kava, St. John’s Wort, Valerian and Echinacea
What is the approach to the obstructed airway?
1 Reposition patient flat and supine
- Head tilt, jaw thrust and chin lift
- Prep in case you need to insert an airway.
What are the options for securing the upper airway and respective contraindications?
Oropharyngeal airway - can’t use if they have a gag reflex or there’s a foreign body
Nasopharyngeal airway - cna’t use if there is nasal fracture, bleeding or coagulopathy
Describe how to hold the face and jaw in order to create a good seal for bag-mask ventilation
Hook the 5th finger around the angle of the jaw and use it to move the mandible forward (jaw thrust), and position 3rd and 4th fingers under the chin for a chin lift / head tilt. Hold the mask with index and thumb. Squeeze the bag with the dominant hand
What are the indications and contraindications of the LMA?
Indications: short procedure, as a rescue device if intubation fails or to secure the airway outside of hospital
Contraindicated if can’t open mouth, at increased risk of aspiration or there is infraglottic obstruction, patient is prone or there is a need for high ventilator pressures.
When should you consider rapid-sequence induction?
Non-fasted patient.
Pregnancy, severe diabetes or other condition causing delayed gastric emptying such as bowel obstruction
Severe GERD
How does rapid-sequence induction differ from standard induction?
Key is “skip” bag-mask ventilation and go quickly from fully conscious patient in control of their airway to intubation. Differs in that the induction occurs through pre-selected IV bolus + rapid acting muscle relaxant
Cricoid pressure used to “seal” esophagus (controvertial if needed…)
What is the most important contraindication to rapid-sequence induction?
Patients with anticipated difficult airway
How do you respond to a Can’t Intubate / Can’t Oxygenate situation?
Call for help, Attempt LMA
Bag-mask, jaw thrust to maintain ventilation
reawaken patient.
Try to avoid by planning ahead.
How do you recognize airway obstruction?
Resp < 8 or > 30 / min
O2Sat < 90 on 50% > 6 L /min
Stridor / Secretions / Drooling / Laryngospasm
How to manage laryngospasm?
Call for help 100% oxygen Remove oral stimulus Pharyngeal suction CPAP PPV with bag/mask tight seal
How do you differentiate a lower airway crisis?
Bronchospasm, wheeze, high pitch expiration.
What are the first steps to do with an unresponsive patient who is not breathing or who has abnormal breathing?
1) Call for help
2) Check pulse
3) Start CPR (if no pulse or unsure)
4) Apply oxygen if you have a second responder
5) Attach monitors and defibrillator
What are the 4 pulseless rhythms?
- VFib
- V Tach w/o pulse
- PEA (Pulseless Electrical Activity)
- Asystole