Cardiac Anesthesia Flashcards
Prophylaxis of infective endocarditis
Dental procedures in
- Prosthetic cardiac valves
- Previous IE
- Several types of congenital heart disease (CHD)
- Cardiac transplantation recipients who developed valvulopathy
Hypothermia
- Plt sequestered reversibly in portal circulation
- Plt # back to normal w/I 1 hr
- Plt function & life span normal
Energy for one MET
One MET=energy expended during 1 min at rest = 3.5 ml oxygen/kg/min
CHD w/ right to left intracardiac shunt
- Tetralogy of Fallot
- Eisenmenger’s syndrome
- Ebstein’s malformation of tricuspid valve
- Pulmonary atresia w/ VSD
- Tricuspid atresia
- PFO
ECG
- examing more than one lead is important
PAC migration (922 ?)
- common (3-5 cm distally) withdrawal 3-5 cm before bypass
2. wedge position—>increase in PAP (r/o inadequate ventricular venting–>PAP w/o change after withdraw
malposition of aortic cannula
unilateral facial blanching
malposition of venous cannula
- too far into SVC (obstruction of R innominate vein) or
IVC (abd distention) - facial or scleral edema (bulging sclerae) or poor blood return to bypass circuit
transposition of great vessels
- failure of truncus arteriosus to rotate–>aorta from RV, PA from LV
- induction: volatile—->slow; IV—>faster—>decrease dose
Fontan procedure
- anastomosis: RA appendage—>PA
- tricuspid atresia, pulmonary stenosis, pulmonary artery atresia; hypoplastic left heart syndrome (–>increase PBF–>prepare convert RV to systemic ventricle)
metabolic rate in CPB
Each degree Celsius decrease—>5 to 8% decline
Itra-aortic balloon pump (IABP)
- Inflation immediately after closure of aortic valve (diastole)—>increase DBP & coronary BF
- Deflating just before ventricular systole—> Reduce aortic pressure and afterload—>enhance LV EF, reduce wall tension & VO2
Afterload reduction beneficial
- AI
- MV
- CHF
- PDA
Protamine
- From sperm of fish (certain)
- basic
- specific antagonist of heparin
- 1.3 mg/100 U of heparin
- Can bind plt & coagulation factors—>anticoagulant
- Allergy: NPH insulin
- Hypotension
Primary determinants of myocardial O2 consumption, from most to least important
HR>afterload>preload
Plusus paradoxus
- Pulsus paradoxus: inspiratory fall in SBP>10 mmHg<—cardiac tamponade
- occasionally: severe airway obstruction, RV infaction
pulsus parvus vs pulsus tardus
- Pulsus parvus: diminished pulse
- Pulsus tardus: delayed upstroke
3, In AS
Pulsus alternans
- alternating smaller and larger pulse waves
2. severe LV dysfunction
Bisferiens pulse
- pulse waveform w/ 2 systolic peaks
2. AVR
ETT drugs
ALONE: Atropine, Lidocanine, Oxygen, Naloxone, Epinephrine (Vasopressin may be)
MAP
MAP = DBP +1/3 (SBP-DBP)
= 1/3 SBP + 2/3 DBP
Amiodarone
- structure similar to thyroxine—>hypo or hyperthyroidism
- prolong AP w/o change resting potential: atrial & ventrical muscle
3 Effective: recurrent SVT & VT, WPW syndrome - anti-adrenergic effect—>bradycardia, hypoTN–>may be atropine-resistant—->isoproterenol or temporary pacer
SVR
SVR=(MAP-CVP)/COx80
1. MAP & CVP: mmHg
2. CO: L/min
(1 wood = 80 dynes/sec/cm-5)
dobutamine
predominantly beta 1-agonist
beta 1 vs beta 2 stimulation
Beta 1 stimulation 1. heat: HR, contractility, conduction velocity 2. release of fatty acids Beta 2 1. vascular, rennin sectetion 2. airway 3. uterine relaxation 4. glycogenolysis, gluconeogenesis alpha: intestinal and urinary bladder-sphincter tone
hypertrophic cardiomyopathy–anesthesia
- goal: reduce gradient across LV outflow obstruction
2.avoid inotrope, reducing preload or afterload
3 halothane: direct myocardial depressant, not decrease SVR—>ideal - If hypotension—>phenyephrine
wide complex tachycardia—>unstable
- presumed: ventricular tachycardia (VT)
- medical emergency
- synchronized cardioversion
Romano-Ward syndrome
- congenital
- prolong QT interval
- If plus congenital deafness–>Jervell-Lange-Nielsen syndrome
- etiology: likely imbalance: R & L sympathetic system
- L stellate ganglion block—>shorten of QT—>surgical gangionectomy
VAD
- Axiao = continuous, non-pulsatile
- NIBP not accurate—> A-line
- SPO2 may not work
Normal person, ?% CO is dependent on atrial kick
20 to 30 %
but pathologic —>higher, e.g. AS
Tetralogy of Fallot (1 yo) –GA
- Goal: maintain SVR
2. Ketamine 3 to 4 mg/kg IM or 1 to 2 mg/kg for induction
MS
- rheumatic fever in childhood (almost exclusively)
- LV: ‘protected’=unloaded,
- LA: decrease compliance & function—>pulmonary—>RV
PAC–> V wave on wedge pressure tracing
ischemia of posterior wall of LV & posterior leaflet of MV—>prolapse–>retrograde flow into LA–>V wave (can be earlier than ST depression (–>nitroglycerin)
Wide complex tachycardia of undetermined origin
If stable—>amiodarone 150 mg IV over 10 min—>repeat prn till 2.2 g over 24 hrs
amount of contisol
- normal: 15 - 20 mg/day
2. Max stress: 75 - 150 mg/day
pace maker
- stimulation threshold: increased by hypokalemia & respiratory alkalosis; vasa versa—>vulnerable to VF
- decrease in HR >10%—>faterry failure–>cancel elective surgery–>evaluate
- Anesthesia: ECG moniotor, emergency equipment(e.g, defibrillator, magnet), durgs (atropine, isoproterenol)
Fick equation
- Q=VO2/(CaO2-CvO2)
- CaO2=1.36 HgB x SaO2 + 0.003xPaO2
- CvO2=1.36 HgB x SvO2 + 0.003xPvO2
- VO2 = 4 ml/kg <—-O2 consumption
Normal resting myocardial O2 consumption
Normal: 8 - 10 ml/100g/min—->2 in firillating heat @ 22 Celsus degree
AS
- angina
- syncope
- CHF
Note: new Af—>electrical cardioversion
Prussure
RA: 3-8mmHg RV: 15-30/3-8 mmHg LA: 4-10 mmHg LV: 100-120/3-12 mmHg PA: 15-30/4-12 mmHg
PEEP
- pressure to exhalation valve @ end of expiratory
- FIO2>0.5—>PEEP—>reduce O2 toxicity
- Expand collapsed but perfused alveoli–>decrease V/Q
- Decreased CO, pulmonary barotrauma (i.e., tension pneumothorax, pneumomediastinum, s.c. emphysema), increased extravascular lung water, redistribution of pulmonary BF5
- If abrupt deterioration of SPO2 & CV fx—>suspect baratrauma–>CXR; tension pneumo–>chest tube
coronary artery BF
- Resting coronary artery BF: 75ml/100g/min–> 225 to 250 ml/min–>4 to 5% CO
- Resting myocardial O2 consumption: 8 to 10ml/100g/min—>10% total body O2 consumption
Pulmonary artery rupture associated with PAC
- rare
- hallmark: hemoptysis: may be minimal or copious
- Try to separate lungs: DLETT
- Atheromatous: not risk<—minimal or absent in middle or distal PA where tip of PAC is
Protamine reaction
- Diabetics taking NPH or PZI insulin, but not regular insulin
- seafood allergy
- vasectomy: Antibody to spermatozoa
heparin vs protamine
- 100 u heparin = 1.3 mg protamine
- basic protamine vs acidic heparin
- t1/2 of heparin = 1.5 hrs at 37 cesuls degree
cardiac perfusion
- LV: during diastole–>increase HR–>decrease
2. RV: diastole and systole
thromboelastogram
- viscoelastometer measuring viscoelastic properties of blood during clot formation
- R value=reaction time: NL 7.5 to 15 mins
- K value reflecting clot formation time: NL 3 to 6 mins
- MA=max amplitude (max clot strength rate of clot destruction=fibrinolysis): -5 mm
170 micrometer filter
1 .present in standard blood administration sets
- filtration of possible clots
- Used for: Plt, FFP, Cryoprecipitate, pRBC, and granulocyte concentrate transfusion
Adenosine
- SVT: 6 mg IV–>repeat if needed 1-2 min later 12mg
- Including WPW syrdrome (unless AF w/ wide complex WPW occurs—>increase HR)
- Dipyridamole or CVC: initial dose 3mg
- Methylxanthine (caffeine, theophylline, amrinone)–>competitive antagonist to adenosine–>increase dose
body temperature measurement
- PA, distal esophagus, tympanic membrane, or nasopharynx–>reliable even during rapid thermal perturbations such as CPB
- oral, axillary, rectal, urinary bladder–>reasonably except during extreme thermal perturbation
- In CPB pt measuring temp of both bladder and PA is helpful in determing likelihood of recooling after CPB
best intraop TEE view for monitoring myocardial ischemia
- transgastric mid-papillary short axis view
2. supplied by all 3 major coronary ateries
sodium bicarbonate–>adverse effects
- plasma hyperosmolality
- paradoxic cerebral spinal fluid acidosis
- hypernatremia
- hypercarbia
hypercyanotic ‘tet spells’ in TOF
- mechanism unknow: spasm of infundibular or decrease of SVR
- mgt: phenylephrine, esmolol or IV fluid (morphine).
sildenafil (Viagra)
- inhibit PDE5 —inhibit breakdown of cGMP
- Milrinone: inhibit PDE3
- NTG & hydralazine: direct acting smooth muscle relaxants
Dural antiplatelet (ASA+clopidogrel)
- DES: mim 1 yr before stopping prior to elective surgery
2. BMS: 1 month
HIT (heparin induced thrombocytopenia)
- type I: nonimmune: heparin bind to plt–>short life–>modest decrease: transient–>insignificant clinically
- type II: immume: ab to complex of heparin and a a PF4–>bind to endothelial cell–>thrombin productin–>thrombocytopenia (>50 reduction of plt) & V/A thrombosis (direct thrombin inhibitor: hirudin, leirudin, bivalirudin or argatroban
clopidogrel
- noncompetitively and irreversibly inhibiting P2Y12 —>action is life long of plt–>no reverse drug
- Platelet transfusion can reverse
port access robotic surgery
- less invasive for coronary artery revascularization
2. mini-thoracotomy–>OLV–>hypoxia
carina vs bronchoscope
- bronchoscope–two branch points: ‘real’ carina—> (L or R) two branch points: L upper lobe & lower lobe or RUL or RML—>3 lumens
hypoxia in OLV
- check position of DLT and correction of poor hemodynamics
- adding CPAP to non-dependent lung
- adding PEEP to dependent lung
- having surgeon clamp PA to lung about to remove
- Intermittent inflation of non-dependent lung w/ O2
transplanted heart
- denervated–>intrinsic HR 110
- bradycardia(25%): eventually developed—>atropine no effect
- Effective: glucagon, isoproterenol, epinephrine, norepinephrine (no reflex bradycardia), pacer
WPW syndrome w/ AVNRT (AV nodal reentrant tachycardia)
- bundle of Kent: connet atria with ventricle w/o passing AV node
- orthodromic: >90%, narrow complex, can use everything mentioned below
- antidromic: travel via accessary pathway, worse, but Can use procainamide or electrical cardioversion
DDD-R reprogrammed to asynchronous (DOO) mode during surgery
- VOO or DOO–>R on T likely if native HR >programmed HR or PVC or PAC
- try Esmolol to decrease HR
Milrinone vs amrione (inamrinone)
- PDE 3 inhibitor—>increase CAMP —>positive inotropic and vasodilation
- Amrinone —>thrombocytopenia, but NOT milrinone
SVR vs PVR
SVR = (MAP - CVP )/CO
PVR = (PAmean - LA pressure)/CO
type of -tropy
- chronotropy: HR
- dromotropy: conduction
- inotropy: force & velocity of ventricular contration
- lusitropy: myocardial relaxation
- bathmotropy: muscular excitation to stimulus
adrenergic receptors vs ach-receptors
alpha 1 (a, b, c) alpha 2 (a, b, c) beta 1, 2, 3 M1- M2-heart M3-coronary circulation M4- M5- (M1, 3, 5: Gq/11-->PLC-->DAG; M2, 4-->Gi/o--> (-) AC (M2 receptors can couple to K+ channels and influence the activity of calcium channels, If current, phospholipase A2, phospholipase D, and tyrosine kinases)
Bainbride reflex
stretch receptors in RA &cavoatrial juntin
Bezold-Jarisch reflex
- vagal reflex
2. noxious ventricular stimuli
oculocardiac reflex
eye surgery
baroreceptor reflex
maintaining BP
SvO2 decrease vs increase
- Normal: 60-80%
- Decrease: Hypoxemia, low CO, anemia, increased oxygen consumption
- Increase: decreased oxygen consumption (e.g. cyanide toxicity), elevation in CO, normalization of hemoglobin, improvement in oxygenation
Ketamine
- Return to full orientation takes approximately 15-20 minutes after a typical induction dose of 2-2.5 mg/kg
- active metabolite for ketamine: nonketamine
- The safe use of ketamine in pregnancy has not been established, and such use is not recommended.
milrinone vs amrinone
- Phosphodiesterase III inhibitors–>increase cAMP in cardiac & smooth muscle–>+inotropic & vasodilation (A & V)
- amrinone: throbocytophenia
SIRS vs sepsis
SIRS needs 2 or more: 1. T>38 or 90 3. R>20 or PaCO2> 32 4. WBC >12,000 or 10% immature (band) forms Sepsis = SIRS + documented infection
Distance from RA of PAC
- RIJ: 20-25 cm (but RV: 30 - 35 cm; PA: 40 - 45 cm; wedge: 45 - 55 cm)
- LIJ, LEJ, REJ: add 5 to 10 cm
- Feoral: add 15cm
- 30 to 35 cn from antecubital veins
pulmonary hypertension
- mean PA >25 at rest or >30 mmHg w/ exercise
- Epoprostenol = prostacyclin (PGI2); alprostadil (PGE1): central IV or inhale
- O2
- nitric oxide (NO): inhaled (1-80 ppm, typicl 20-40 ppm
- Milrinone: also inotropic, ? inhale
- inhaled volatile anesthetics
NOTE: nitrous oxide increase PA resistence
PVR as a function of lung volume is the least at ?
functional residual capacity (FRC)
Least likely to cause unfaovorable hemodynamic changes in MS ?
ketamine, remifentanil, pancuronium, desflurane, nitrous oxide
Remifentanil
torsades de pointes (twisting of the points)
- can be induced by: drugs (e.g., quinidine, procainamide, phenothiazines like droperidol), electrolyte abnormalities (hypokalemia, hypomagnesemia), ACS
- If prolonged QT present: shortening QT is time permits: overdrive atrial or ventricular pacing (more definitive), MgSO4 (1st line emergency), isoproterenol (past)
- If no prolonged QT: std drugs for VT
- hemodynamically unstable–>unsynchronized shock