E-Modules Second Pass Flashcards
What are the “special patient groups” for which you should know specific things?
Pediatric, geriatric, obstetric
Why do pre-op assessment?
Establish the safest plan for the pt
What are the goals of the pre-op assessment?
- RV med Hx
- Assess airway, cardioresp, other systems
- Make a plan to optimize
- Determine post-op disposition (where pt will recover)
- Alleviate anxiety and build rapport
- Delay the surgery if necessary
What are the components of the pre-anesthesia exam?
- Prepare
- Hx
- Physical exam
- Review the plan
- Any questions?
What things must you (and the surgeon) make sure are correct?
Correct patient, procedure, and side
What details do you want to know about a pt PMHx?
Ask PMHx, but also Qs to get a sense of severity and level of control. Eg if OSA, on CPAP? Using? Effective? If DM, ask about A1C, meds, micro and macrovascular complications
What details do you want to know about a pt PSHx?
what kinds of anesthetics have they had
Hx of post-op N&V
Specifically about malignant hyperthermia and pseudocholinesterase deficiency
What features of MH might a pt know or think of, if not familiar with the name?
“tense muscles”, “a severe fever”
What features of pseudocholinersterase deficiency might a pt know or think of, if not familiar with the name?
“muscle relaxant took a long time to wear off”
What should you do if you suspect MH or PD?
Inform staff immediately
What FHx should you ask about?
malignant hyperthermia and pseudocholinesterase deficiency
What should you ask about in the med Hx?
What meds, and also what day they last took each
Periop plan should be in Anesthesia or other (eg Thrombosis) consult
Why should a pt not smoke the day of the surgery?
Hb higher affinity for CO than O2, so pt will be more prone to desaturation
What smoking Hx should you ask?
Standard ever-smoked & pack-years; also, when they quit if so, and if a current smoker when last cigarette was.
What social Hx should be inquired about/
Substance use, esp chronic use (might affect sensitivity to meds) or IVDU (poor venous access)
What is one question you have to remember to ask day-of-procedure, and what should you do if you’re not sure pt is being honest?
NPO status!
Tell pt how serious it is – they could die – and they usually take it seriously.
What are the CAS guidelines for preop fasting?
Clear liquids up to 2h beforehand
HBM (infants): up to 4h beforehand
Infant formula, light meal, non-human milk: up to 6h beforehand
Large meal, fried foods, fatty foods, meat: up to 8h beforehand
What are the ASA classes?
1: A normal healthy patient in need of surgery for a localized condition.
2: A patient with mild to moderate systemic disease; examples include controlled hypertension, mild asthma.
3: A patient with severe systemic disease; examples include complicated diabetes, uncontrolled hypertension, stable angina.
4: A patient with life-threatening systemic disease; examples include renal failure or unstable angina.
5: A moribund patient who is not expected to survive 24 hours with or without the operation; examples include a patient with a ruptured abdominal aortic aneurysm in profound hypovolemic shock.
What does the E mean in ASA classes?
Emergency surgery
Why should you obtain baseline vitals?
Get a sense of how far off you are from pt normal during surgery
What is the average risk of dental damage with intubation?
1 in 500 on average
What are the required parts of the pre-op anesthesia exam?
Airway exam, discuss dental damage, CV and Resp, Venous and Arterial exam (eg Allen test), spine exam
Why would you consider a neuro exam as an additional component of the pre-op anesthesia assessment?
- positioning: risk of injury
- blocks: want to know how well the affected area functions normally
- risk of stroke: assess baseline so you can assess if there is worsening
What are the physiologic changes in a pregnant pt in the CV system?
Increased CO (SV & HR)
Progesterone induced vasodilation
Compression of the uterus in supine position
What is supine hypotensive syndrome, and how is it addressed?
Uterus compresses VC, decreased venous return, decreases preload, leads to hypoperfusion
Look out for drop in BP, pallor, tachycardia
Tilt pt to L lateral to lift fetus off IVC
What are the implications of the physiologic changes in a pregnant pt in the CV system?
More strain on heart (issue if pt has heart trouble)
Hypotension
Supine hypotensive syndrome
What are the physiologic changes in a pregnant pt in the respiratory system?
More edematous and vascular
Increased adipose tissue
Decreased Functional Residual Capacity (cephalad displacement of diaphragm)
How do you prepare pregnancy women immediately before surgery that is different?
Pre-oxygenation (due to decreased FRC)
What are the physiologic changes in a pregnant pt in the GI system and what are the risks because of them?
Decreased tone in LES
Decreased gastric emptying
Increased gastric acidity
Increased intra-abdo and gastric pressure
–> heartburn, reflux, aspiration, and more severe damage (due to pH)
How do anesthetists manage pregnant pt differently from a GI perspective?
Treat as recently-eaten, & give intraop PPI
What are the physiologic changes in a pregnant pt in the CNS and what are the risks because of them?
Increased minute ventilation
Decreased min alveolar concentration due to hormonal changes
So:
- increased sensitivity to anesthetic agents
- faster onset of inh agents
- faster induction and emergence
Ie, they require dosage adjustments.
What are the takeaway points of physiological differences of pregnant pt and the implications for anesthesia?
- incr sensitivity to anesthetic agents
- more diff intubation
- potential for gastric reflux and aspiration
- increased susceptibility to hypoxemia
- supine hypotensive syndrome
Where is pain felt in stage 1 of labour?
Paracervical nerves: T10-L1
Where is pain felt in stage 2 of labour?
Paracervical nerves: T10-L1
and
Pudendal nerves: S1-4
Where is the epidural injected? How do you know if you’ve gone too far?
Epidural space – just OUTSIDE the dura
If CSF comes out you’ve gone too far!
Why do epidurals work?
Nerve roots pass through the epidural space as they exit the spinal cord. Anesthetic there numbs the roots.
Why are epidurals preferred for labour?
Pt remains awake
Superior pain relief
No direct effect on fetus
Good for more complicated procedures – eg C-sections, forceps
Indicated for hypertension: prevents catecholamine surge from pain, vasodilates
What are the downsides of epidurals?
Labour *may* take longer (being contested) Hypotension Muscle weakness (may affect motor nerves)
What is done to avoid negative effects of epidurals?
Fluid boluses, vasopressors, pt positioning
Which takes more time, spinal or epidural?
Epidural
Spinal can be done if not enough time for epidural, eg urgent C section or planned elective C section
When would you use a pudendal block, and how is it done?
Pt has advanced far into labour without anesthesia but now need vacuum or forceps
Usually done by attending OB, not anesthesia
Done through vaginal wall
When would you use GA?
Urgent procedure
Contraindication to regional technique
What size cuffed ETT does CPS recommend?
up to 1 y: 3.0mm
1-2y: 3.5mm
>2y: (age in years / 4) + 3.5mm
What is the sizing difference between cuffed and uncuffed ETT?
add 0.5mm
so formula for uncuffed tubes is tube size = age/4 + 4mm
What SSHADESS history should you make sure to ask a child, separate from an adult?
Tobacco, alcohol, other substance use, contraception & pregnancy
What anatomical differences between kids and adults are particularly important to note?
- relatively bigger heads, particularly occiput, making angles diff for intubation (put rolled towel under scapulae, enabling “sniffing position)
- epiglottis shape, size, and compliance is different (straight laryngoscope more often used to lift the epiglottis, instead of curved into vallecula)
- larynx more cephalad (C4, as opposed to C8)
What is Poiseuille’s law?
resistance is inversely proportional to the radius of the tube to the 4th power
(radius, not diameter)
What is different about cardiac output changes for kids generally?
Hearts are less compliant, so SV changes less: CO mostly modified with HR
What is different about vagal tone in kids?
Increased, so more likely to get bradycardic with laryngoscopy or hypoxia
What is different about kids’ pulmonary tissue, and how does that affect anesthesia?
Tissues are more compliant, so they are less likely to keep negative intrathoracic pressure, so hypoxia happens faster
What is different about the BBB in infants?
More permeable than in adults: meds can cause central effects, eg apneas
What physiologic differences in the liver might change dosing requirements in infants?
At birth, hald of CYP450 non-functional, so active metabolites build up more
Phase 2 conjugation reactions, which make metabolites more water-soluble, not functional in infants: decreases excretion of active drug metabolites
What physiologic differences in the kidney might change dosing requirements in infants?
Infants can’t process high solute load or high amounts of free water; might lead to decreased excretion of medications, leading to long half-life
Glomerular filtration matures by age 2
What fluid bolus is usually given at the start of peds cases, and why?
10-20 mL/kg bolus usually given at start of case
Intraop fluid req may be increased due to blood loss, insensible losses, volume deficits from pre-op
How is body temperature managed differently with young kids?
Body surface area relatively larger, so increased risk of hypothermia: warming blankets & avoiding exposure is more common.
How do you calculate maintenance fluids for kids?
4-2-1 rule
What is physiologic pain?
Response to a known stimulus, and promotes a protective function
Acute: recent onset, short duration, disappears with healing/disease resolution
What are nociceptors?
Primary afferent neurons
A-delta and C fibres
Innervate peripheral tissues (skin, muscle, joints, viscera)
What role do inflammatory mediators play in pain?
Activate peripheral nocioceptors
What are the 4 stages of pain response?
Transduction, Transmission, Modulation, Perception
What is modulation?
Process which determines how nociceptive info will be transmitted in the CNS
Modified in periphery, in dorsal horn and in descending pathways
How does peripheral sensitization work in pain?
Inflammatory mediators sensitize functional receptors and activate dormant ones
(–> easier activation, more firing)
What may happen if the acute pain response is not interrupted?
May progress to chronic/pathologic pain: approach pain aggressively!
What is the neuro-endocrine stress response to pain?
- increased sympathetic tone
- increased catecholamine and catabolic hormone secretion
- decreased secretion of anabolic hormones
- enhancement of coagulation
What is the result of the neuro-endocrine stress response to pain?
- sodium and water retention
- catabolic and hypermetabolic state with increased oxygen consumption
- hypergoaculability, immunosuppression, hyperglycemia, poor wound healing, risk of myocardial ischemia, decreased GI activity
What are the treatment options for management of post-op pain?
Systemic: opioid & non-opioid; oral/IV/IV-Patient controlled analgesia (PCA)
Regional: Neuraxial (spinal, continuous epidural, pt-controlled epidural); periperal (nerve blocks, intra-articular injections, etc)
What is chronic pain?
Persistent or recurrent pain, lasting beyond course of acute illness or injury
- low levels of identifiable pathology
- not assoc w/ adaptive or protective response
- pathologic
What is the IASP definition of pathological pain/chronic pain?
Pain without apparent biological value that has persisted beyond the normal tissue healing time usually taken to be 3 months
What does malignant chronic pain relate to?
pertains to cancer and its treatment
What does nonmalignant chronic pain deal with?
neuropathic, MSK, inflammatory
