Term
Halothane is a ________ (chemical makeup)?
Halogenation influences _______. |
|
Definition
Halogenated Hydrocarbon (alkane derivative)
Halogenation influences potency. |
|
|
Term
How does Halothane being an alkane derivative effect its action on the heart?
This does not occur with ____ ? |
|
Definition
Halothane has arrhythmogenic properties
Alkanes with 5 halogens are more prone to induce arrhythmias
than ethers with 6 halogens like Enflurane and Isoflurane
|
|
|
Term
| Halothane produces ___________ arrhythmias. |
|
Definition
| Halothane produces atrial and ventricular arrhythmias. |
|
|
Term
Why is Halothane stored in amber bottles?
Are all IAs in these type of bottles? |
|
Definition
Because they give the OR a masculine look.......And because its unstable in light.
YES |
|
|
Term
Is Halothane flammable?
What is the preservative for Halothane? |
|
Definition
NO (d/t halogenation)
Thymol
*Only IA with a preservative
Prevents spontaneous oxidative decomposition |
|
|
Term
1.1 MAC of Halothane increase CBF 200% with BP support. What if the BP is low?
Autoregulation of CBF is intact normally (without Halothane on board) with blood pressure between _____ & _____.
....with HTN pts between _____ and _____. |
|
Definition
Cerebral flow is BP dependent because halothane abolishes autoregulation
60-150mmHg
60-180 or 200mmHg
|
|
|
Term
| Autoregulation of CBF is intact with isoflurane. T/F |
|
Definition
|
|
Term
| How will Halothane affect ICP? |
|
Definition
| With normal blood flow, increased ICP. |
|
|
Term
| How can we prevent the increased ICP seen with Halothane? |
|
Definition
Prevented by prior hyperventilation to
PaCO2 <30 Torr
*Must hyperventilate prior b/c Halothane = depression of vascular CO2 response per Kaye |
|
|
Term
| How will Halothane affect CMRO2? |
|
Definition
| Dose dependent decrease in CMRO2. |
|
|
Term
| Halothane does not effect BAEP, but what technique is better? |
|
Definition
IV agents are better.
If using IA's keep levels stable The combo of volatile with opioid and N2O is better than volatile agent alone. |
|
|
Term
| Halothane also doesnt effect the ability to monitor VEP and SSEP. T/F |
|
Definition
|
|
Term
How does Halothane affect CSF?
Which is the only IAs that has a potentially negative effect on CSF, esp on pts with increased ICP? Why? |
|
Definition
Decreased production and decreased absorption
Enflurane -inc. production and decr. absorption |
|
|
Term
| How will Halothane effect SNS response to arterial pressure? |
|
Definition
Halothane reduces overall sympathetic activity
Attenuates sympathetic responses to decline in arterial pressure
Depresses baroreceptor reflex control of arterial pressure |
|
|
Term
How will Halothane effect NE release from post ganglionic sympathetic nerves?
How does Halothane effect postsynaptic nicotinic receptors?
Halothane also contributes to depression of __________ in peripheral blood vessels |
|
Definition
Reduces NE release
Depresses them
reflex vasoconstriction
|
|
|
Term
| Tell me about Halothane and the vagus nerve. |
|
Definition
Halothane depresses vagal nerve efferent activity
Inhibits reflex bradycardia in response to increases in arterial pressure |
|
|
Term
Which anesthetic has equal effects on PNS and SNS as Halothane?
How might Halothane and Isoflurane benefit patients with heart failure and CAD? |
|
Definition
Isoflurane
Both produce beneficial decreases in LV preload and afterload in patients with heart failure and CAD. |
|
|
Term
What causes Halothanes depression of BP?
Does Halothane depress myocardial contractility? How much in comparison of other IAs? |
|
Definition
Alterations in intracellular CA++ leading to negative inotropic effects.
YES
H & E > I
|
|
|
Term
| Beta blockers, calcium channel blockers may increase the magnitude of BP depression with Halothane. What is to be done with these medications preoperatively? |
|
Definition
|
|
Term
| What is Halothanes effect on HR? |
|
Definition
Slows the rate of SA node discharge
Prolongs atrioventricular conduction time & refractoriness
Bradycardia risk; especially in peds |
|
|
Term
| With increased MAC above 1.0 you usually see a drop in BP, SNS activity, & CO; thus what effect is seen on HR in these circumstances with Halothane? |
|
Definition
should see HR increase but dont b/c halothane depresses the Baroreceptor reflex
*I = incr HR till 1.0 MAC then evens out
*D, & S = HR inc. w/ inc. MAC (baroreceptor intact) |
|
|
Term
| What about that Epi the surgeon is giving while I run Halothane down here in Haiti? |
|
Definition
Its bad b/c halothane sensitizes pt to epi induced arrhythmias
reduces threshold for atrial & vent arrhythmias
Escalating doses of epi produce PVC's & sustained v-tach |
|
|
Term
Epi admin with halothane can be endogenous (crying child) or exogenous. T/F
IF you cannot avoid epi with Halothane then limit dose to _____ and _____ .
|
|
Definition
True
0.1mg in 10 min
0.3mg in 60 min |
|
|
Term
Which other IAs need low epi use to decrease risk for epi induced arrhythmias?
How much epi is okay to give with each? |
|
Definition
Iso and Enfl
Double dose of H with E
Tripe dose of H with I |
|
|
Term
Lidocaine is protective when given with epi and is treatment of choice for epi induced arrythmias. T/F
What can you do with epi dose if you give lido too? |
|
Definition
|
|
Term
How will Halothane effect TV?
RR?
minute volume?
PaCO2? |
|
Definition
decreases dose dependently
increases dose dependently
Stable till over 1.0 MAC and then decrease
increases dose dependently |
|
|
Term
| How will Halothane effect airway resistance? |
|
Definition
Potent bronchodilator
Dose dep. decrease in resting airway resistance |
|
|
Term
| Why are the patients in PACU at risk for hypoxia after Halothane? |
|
Definition
Hypoxic resp. drive is depressed profoundly;
esp. concerning in PACU when the patient has decreased stimulation. |
|
|
Term
| Remember COPD pts depend on the hypoxic drive to breath so it is probably not good to utilize ____ ventilation with these pts. |
|
Definition
|
|
Term
Why does Halothane cause a decrease in GFR and renal blood flow?
Do other IAs cause a decrease in GFR and renal blood flow? |
|
Definition
Due to decreased CO and decreased BP; Not effect of anti-diuretic hormone and autoregulation of renal BF is intact
YES (E and I do) per Kaye |
|
|
Term
| Since autoregulation to renal blood flow is intact with Halothane, how can we attenuate the effects of a decreased CO and BP? |
|
Definition
|
|
Term
| Why don't we use Halothane in OB/Gyn? |
|
Definition
Its illegal in the U.S. and: Relaxes uterine muscle and inhibits contractions
Increases blood loss w c-section & therapeutic abortions |
|
|
Term
When is the only time Halothane might be useful in OB/Gyn?
Usual dose of IAs in OB/GYN to be safe and decrease bleeding risk is ___ MAC |
|
Definition
To provide uterine relaxation with retained placenta fragments
0.5 MAC or less (w N2O added) |
|
|
Term
| Halothane is eliminated ____ than iso or enfl despite its higher BG p.c. b/c of what? |
|
Definition
|
|
Term
| Why is Trifluoroacetic acid a problem? |
|
Definition
In genetically susceptible patients an antigen is formed that provokes the formation of antibodies
On second exposure a sensitivity reaction occurs leading to halothane hepatitis |
|
|
Term
| Which IA is there a potential for cross sensitivity with Halothane concerning trifluoroacetic acid? |
|
Definition
Enflurane and Isoflurane
least with Desflurane (b/c least metabolized)
None with Sevo |
|
|
Term
| How would you treat Halothane induced dystrhythmias? |
|
Definition
|
|
Term
| Risk for malignant hyperthermia with halothane? |
|
Definition
|
|
Term
| What has replaced Halothane in the OR for mask inductions? |
|
Definition
|
|
