Chapter 32 - Preoperative evaluation Flashcards
American society of anesthesiologist classifications
ASA 1 = healthy good exercise tolerance ASA 2 = controlled medication without significant systemic effects ASA 3 = medical condition with systemic effects; functional compromise ASA 4 = medical condition with significant dysfunction; potential threat to life ASA 5 = critical condition, little chance of survival with or without surgery ASA 6 = brain death, organ donation
AHA/ACC categorization of vascular surgery by type
Intermediate risk = CEA, EVAR High risk = every other major vascular surgery
Cardiac testing not necessary before vascular surgery in these cases
1) Adequate functional capacity > 4 METs 2) coronary revasc within 5 years 3) normal coronary angio or stress test within 2 year
Stepwise approach to perioperative cardiac assessment
FIGURE 32.1
Cardiac implantable electronic devices and surgery
Monopolar electrocautery can cause problems need magnet
POISE trial key point
beta blocker helps with reducing primary cardiac events high dose beta blocker in naive patients can be harmful
DECREASE-IV trial
beta blockers started well before surgery titrating HR 50-70 is cardioprotective
CARP trial
1) stable CAD 2) CABG or PCI does not improve long term outcomes 3) pre-op cardiac surgery cause increase procedure-related complication EXCEPT LM > 50% disease both LCX and LAD occlusion
HTN before surgery
Delay if > 200 mmHg systolic > 120 mmHg diastolic delay elective Hydrate patient to prevent sudden hemodynamic shift
Factors related with pulmonary complication
1) COPD 2) age > 60 3) ASA >2 4) functionally dependent 5) smoking 6) FEV < 1L 7) CHF 8) obesity
Treatment for COPD and bronchospasm before surgery
1) inhaled bronchodilator 2) beta 2 agonist 3) anticholinergic start 5 days before surgery 4) steroids if FEV1 < 80%
Lung expansion techniques
1) incentive spirometry 2) chest physical therapy 3) cough 4) postural drainage 5) ambulation 6) continuous positive airway pressure
Treatment of hyperkalemia
1) Polystyrene binding resins 2) insulin with dextrose 3) calcium carbonate 4) IV bicarb 5) dialysis
Problem with uremia
1) platelet dysfunction 2) increase incidence of perioperative bleeding
Option to improve uremia-induced platelet dysfunction
1) dialysis 2) desmopressin 3) cryoprecipitate 4) conjugated estrogen 5) tsf RBC or platelet
Methods to limit contrast-induced nephropathy
1) avoid contrast 2) use only non-ionic low osmolar agents 3) hydration with isotonic saline
HbA1c and surgical complicadtions
< 7% decreases infection by 2.13x lower 30 day mortality
Perioperative glycemic management with insulin key points
1) avoid alteration of long acting basal insulin day before surgery 2) reduce evening NPH to 75% day before surgery; only 50-75% morning of surgery 3) no prandial insulin when fasting 4) maintain glucose 100-180 mg/dl 5) for patients not insulin naive, use 60-80% of calculated daily insulin requirement based on last 6hr of iv insulin 6) if naive, use 50%
Stress dosing of steroids key points
< 5 mg/day prednisone (4 mg methylpred, 0.5 mg dexamethasone, 20 mg hydrocortisone) for < 3 weeks = no intraop steroid coverage but keep taking doses > 20 mg/day prednisone = need supplement: 50 mg hydrocortisone intraop and then q8hr for 48-72 hours range 25 - 100 mg based on severity of surgery and taper back to home dose in 1-3 days
Corticotropin stimulation test
250 mcg cosyntropin given IV or IM –> measure cortisol baseline then at 60 min plasma cortisol > 20 mcg/dl (552 nmol/l) at either time is adequate function
Low dose stimulation test corticotropin
1 mcg cosyntropin IV and measure at baseline and 30 min plasma cortisol > 18 mcg/dl (497 nmol/l) = adequate funcdtion
Recommendations for thromboprophylaxis in various risk groups
TABLE 32.2
Patient with history of HIT anticoagulation method
if still have heparin antibodies then use alternative if no antibodies then heparin can be used again
High risk patients needing bridging anticoagulation
1) mitral valve 2) caged/tilting disk aortic prosthesis 3) recent stroke/TIA (6 months) 4) CHADS 5-6 5) afib with rheumatic valve disease 6) VTE (3 months)
LMWH and spinal or epidural
Prophylactic LMWH stopped 10 hours prior, resume 6 hours after therapeutic stopped 24 hr prior and restart 24 hr after
Dabigatran before surgery
stopped 5 days before as per american society of regional anesthesia
Level of albumin signifying malnutrition and risk of mortality
< 3.5 g/dl
Weight loss before surgery in relation to increased mortality
5% in 1 month 10% in 6 month
Albumin half life
18-21 days
Condition for a legal action against physician to be successful
1) provider had duty to care for patient 2) duty of care was breached in deviation from standard 3) breach caused loss or damage to patient
Key components of consent
1) date and time 2) diagnosis explained 3) risk/benefit of procedure explained 4) alternative explained 5) consent read by patient 6) opportunity to ask question 7) express understanding and wish to proceed
