11. Pharmacology Flashcards
What drug can be used in a patient with long QT who develops non-sustained polymorphic ventricular tachycardia?
Mg Sulfate
True or false: Mg Sulfate is unlikely to be effective fr non-sustained polymorphic ventricular tachycardia in patients with a normal QT interval?
True
What do procainamide, sotalol, quinidine and dofetilide do to the QT interval?
Prolong
Type of long QT in a patient with a mutation in Na channel gene SCN5A?
Type 3
What drugs can be considered for a patient with LQT3 and torsades de pointes?
- IV lidocaine
2. PO mexiletine
What constitutes low-risk thrombosis for prosthetic vavles?
Mechanical aortic valve and no risk factors (A-fib, previous thromboembolism, LV dysfunction, hypercoaguable conditions, older-generation thrombogenic valves, mechanical tricuspid valves, more than 1 mechanical valve)
What constitutes high-risk thrombosis for prosthetic valves?
Mechanical mitral valve or mechanical aortic valve + RF (A-fib, previous thromboembolism, LV dysfunction, hypercoaguable conditions, older-generation thrombogenic valves, mechanical tricuspid valves, more than 1 mechanical valve)
Operative anticoagulation plan for low-risk?
Stop warfarin 48-72 hours prior to procedure (goal INR <1.5) and re-start within 24 hours after procedure… no need to bridge
Operative anticoagulation plan for high risk?
Stop warfarin 48-72 hours prior to procedure (goal INR <1.5) and bridge with heparin once INR <2. Stop heparin 4-6 hours after surgery and resume heparin ASAP and continue until INR therapeutic with warfarin
INR goal after mitral valve replacement?
INR 2.5-3.5 (warfarin)
Anticoagulation needed after mechanical mitral valve?
Coumadin (INR 2.5-3.5) and ASA
What are risk factors in terms of anticoagulation needs?
A-fib, previous thromboembolism, LV dysfunction, hypercoaguable conditions, older-generation thrombogenic valves, mechanical tricuspid valves, more than 1 mechanical valve
When should ASA be used for artificial valves?
All mechanical valves, biological valves with risk factors
Anticoagulation for mechanical prosthetic valves in pregnancy?
Chronic warfarin: Can stop between 6-12 weeks gestation and use heparin v. continuing until 36 weeks gestation then transitioning to heparin and delivering in 2-3 weeks
What is lowest fetal risk for anticoagulation in Mom during pregnancy?
Continuous IV UFH
-But, maternal risk of prosthetic valve thrombosis, systemic embolization, infection, osteoporosis, and HIT are higher
Goal Xa if using LMWH in pregnancy?
BID dosing with anti-Xa 0.7-1.2 4 hours after dose
Goal PTT for UFH in pregnancy?
At least twice control
INR goal for warfarin in pregnancy?
2.5-3.5
When does warfarin HAVE to be switched to continuous IV UFH in pregnancy?
2-3 weeks prior to planned delivery
What is the cause of cough as a side effect of ACEi?
Increased bradykinin
What does ACE do?
Converts angiotensin I to angiotensin II
Inactivates bradykinin
What effect to ACEi have on angiotensin II and bradykinin?
Decrease angiotensin II
Increase bradykinin
What drug inhibits the Na-K ATPase?
Digoxin
What do CCB do?
Inhibit Ca entry into vascular smooth muscle
How to ARBs function?
Inhibit activation of angiotensin II receptors
Irregularly irregular wide complex tachycardia, electrical cardioversion didn’t work, what is arrhythmia and which drug most likely to work?
A-fib with preexcitation (conducting antegrade to ventricle via AV node and accessory pathway, some beats are likely fusion beats)
Amiodarone
If you have a-fib with prexcitation, what drugs do you need to avoid?
AV nodal blocking agents - Unopposed ventricular activation via accessory pathway can lead to V-fib
Name some AV nodal blocking agents
- Adenosine
- Dig
- Diltiazem
- B-blocker
What class is amiodarone?
III (slows cardiac conduction)
What is treatment of choice for a-fib with pre-excitation and RVR?
DC cardioversion
-Can use amiodarone if needed (will restore a-fib to sinus rhythm and decrease accessory pathway conduction)
What drug can commonly cause GI upset (nausea/vomiting)?
Digoxin
What can e seen on tele as a side effect of digoxin?
High grade AV block with activation of ectopic pacemakers
What is first line treatment in a patient with cateocholaminergic polymorphic v-tach with a VT/VF storm?
IV beta-blocker
Last resort for a patient with CPVT in VT/VF storm if IV beta-blockade isn’t working?
General anesthesia
Who benefits from palivizumab?
< 24 months with hemodynamically significant cyanotic and acyanotic CHD (meds for HF, mod-severe PH)
What is primary benefit of immunoprophylaxis with palivizumab?
Decrease rate of RSV-associated hospitalization
True or false: Studies haven’t shown a significant decrease in rate of mortality attributable to RSV in infants who receive prophylaxis?
True
How does lasix work?
Inhibits Na-2CL-K cotransporter in the loop of Henle
How do thiazide diuretics work?
Inhibits Na-Cl cotransporter
How does digoxin work?
Inhibits Na-K ATPase
What is the treatment for idiopathic viral pericarditis?
Ibuprofen and ASA
-Help to relieve pain, don’t alter natural history of disease
Dosing of ASA for pericarditis?
Higher dosing- 800mg q6h-q8h for 7-10 days followed by gradual tapering of dose
True or false: Acute pericarditis usually responds dramatically to corticosteroids?
True
What is the use of corticosteroids in acute pericarditis associated with?
Risk of relapsing pericarditis
If NSAID therapy hasn’t worked in acute pericarditis, what other drug can be used?
Colchicine (4-6 weeks)
*Especially if NSAIDS haven’t had benefit after 1 week
What can NIRS be a good surrogate for?
Mixed venous saturation (tissue level saturation/oxygenation)
What is the difference between SaO2 and MVO2 a surrogate for?
CO
Qp:Qs equation?
Ao sat – MV sat / Pulm vein sat- PA sat
How would norepinephrine affect Qp:Qs?
Potent vasoconstrictor, will increase SVR and increase Qp:Qs
When are steroids indicated for Kawasaki?
Fever relapse after 2 doses IVIG
Initial therapy for Kawasaki?
IVIG + high dose ASA
What form of steroids are used if needed in Kawasaki?
IV methylprednisolone (PO not appropriate)
Therapy for mild-moderate carditis due to RF?
High dose ASA (80-100mg/kg/day divided q6h)
Therapy for severe carditis (HF, severe valve regurgitation, significant pericarditis/myocarditis) due to RF?
PO prednisone
Should you use PO steroids + ASA for acute RF?
No- no recommendation to combine these
How does sirolimus work?
Blocks gene transcription
-Acts at a distal site in lymphocyte activation cascade and blocks transcription of activation genes
What are tacrolimus and cyclosporine?
Calcineurin inhibitors
Which drug, cyclosporine or tacrolimus, offers survival advantage in heart transplant patients?
Neither- no survival advantage with one versus other
What is a potential advantage of sirolumis
Less nephrotoxicity
Abx recommendations for RF with carditis and residual heart disease (persistent valvular disease)?
Treatment for 10 years or until 40 years of age (whichever is longer, sometimes lifelong) after last attack of RF
Abx recommendations for RF with carditis, but no residual heart disease (no valvular disease)
Treatment for duration of 10 years or until 21 years of age (whichever is longer) after the last attack of RF
Abx recommendations for RF patients without carditis
Treatment for a duration of 5 years or until 21 years of age (whichever is longer) after the last attack of RF
IE Prophylaxis?
Dental procedures that involve manipulation of either gingival tissue or the periapical region of teeth or perforation of oral mucosa:
- Prosthetic cardiac valves or prosthetic material used for cardiac valve repair
- Previous IE
- Unrepaired cyanotic CHD (including palliative shunts/conduits)
- Completely repaired, 6mo following procedure if prosthetic material used
- Residual defects at the site or adjacent to the site of a prosthetic patch or prosthetic device
- Cardiac transplant recipients with valve regurgitation due to a structural abnormal valve
What dental procedures don’t require SBE prophylaxis?
- Routine anesthetic injections through noninfected tissues
- Dental radiographs,
- Placement/removal of orthodontics/ prosthodontic appliances
- Shedding of deciduous teeth
- Bleeding from trauma to lips/oral mucosa
What drug is recommended as first line for children meeting criteria to start lipid-lowering drug therapy?
Statin
When to consider drug therapy in children for hyperlipiemia?
- > 10 (usually after menarche in girls) and after 6-12 month trial of fat/cholesterol restricted diet
- If LDL remains >190 or >160 + FHx premature cardiovascular disease or >/= 2 other risk factors after vigorous attempts to control
What are risk factors and high risk conditions for hyperlipiemida in kids?
- Male
- Family history of premature cardiovascular disease or events
- Presence of associated low HDL
- High triglycerides
- Obesity and aspects of the metabolic syndrome
- Diabetes
- HIV infection
- SLE
- Organ transplantation
- Survivors of childhood cancer
- Presence of HTN
- Smoking
- Elevated lipoprotein (a), homocysteine and CRP
Why are bile acid-binding resins unlikely to achieve target LDL cholesterol levels in children?
- Poor compliance: GI issues, tastes bad
- Limited effectiveness
When are fibric acid derivatives used in kids?
Severe elevations in triglyceride levels + risk for pancreatitis
True or false: Niacin isn’t routinely recommended for kids with hypercholesterolemia?
True
-Poor tolerance, potential for serious adverse events and limited data
What is the traditional medication for HCM?
B-blocker
If a CCB is used in HCM, which is preferred?
Diltiazem or verapamil
*Dihydropyridine CCB like nifedipine would cause peripheral vasodilation and reflex tachycardia
Why isn’t lasix used in HCM?
Decreases preload and LV filling which can worsen the degree of obstruction
What medication inhibits smooth muscle proliferation and may have the advantage of inhibiting coronary vasculopathy?
Sirolimus
True or False: Sirolimus is a calcineurin inhibitor
False
What type of drug is sirolimus often used in combination with?
Calcineurin inhibitor (cyclosporine or tacrolimus)
*Sometimes sirolimus can be used instead of calcineurin inhibitors (may be less nephrotoxic over time)
Following cardiopulmonary bypass for a Norwood, what medication can increase systemic perfusion?
Phenoxybenzamine
*Anesthesia can’t eliminate stress response with hypothermia and increased SVR
How does phenoxybenzamine work?
Long-acting irreversible alpha-adrenergic blocker… decreases SVR, but can cause hypotension/hypoperfusion
Immediately following a Norwood, what causes an unfavorable Qp/Qs ratio with reduced systemic blood flow and low CO?
Increased SVR
List some post-operative drugs which can help reduce SVR
- Phenoxybenzamine
- Milrinone
- Nitroprusside
- Dobutamine
True or False: Norepinephrine causes systemic vasoconstriction and elevates SVR
True
What is the most common side effect of rabbit antithymocyte globulin (ATG?
Fever (60%)
List side effects of rabbit antithymocyte globulin (ATG)
- Fever (60%)
- Rash (<25%)
- Hyperkalemia (25-30%)
- Abdominal pain (45-40%)
- Myalgia (40%)
- Shivering (55-60%)
What are 2 drugs used in pediatric cardiology that may exacerbate bronchospasm? u
- Adenosine
2. B-blocker
Which last longer… the EP effect of adenosine or the bronchospasm effect?
Bronchospasm (can last a long time)
How does adenosine dosing need to be adjusted in heart transplant recipients?
Give 1/4 to 1/2 usual dose
- Sensitive to adenosine
- Long periods of AV block can be noted at higher doses
What is the half life of adenosine?
<2 seconds
How should adenosine be given?
- Fast as possible with flush following
- Large bore IV
- Close to heart as possible
What are 2 common side effects of adenosine?
- Flushing
2. Hypotension
Why do you need an AED if giving adenosine?
The bradycardia it causes can precipitate other arrhythmias (A-fib or V-tach)
Typical dosing for adenosine in kids?
0.1-0.5mg/kg
MOA Ambrisentan?
Selective endothelin A receptor antagonist
*Doesn’t induce or inhibit cytochrome P450 enzymes
Why is ambrisentan much less hepatotoxic than bosentan?
Metabolized through glucuronidation
MOA Epoprostenol?
Postacyclin (PGI2) analogue
MOA Sildenafil?
Phosphodiesterase 5 inhibitor, works through NO-cyclic GMP cascade
MOA Milrinone?
Phosphodiesterase 3 inhibitor
True or False: ECG changes for Brugada can be dynamic and missed on a single ECG
True
What type of testing can help with diagnosis of Brugada?
Drug challenge with Na channel blockers like procainamide
*This can exacerbate Na channel dysfunction
What are some Na channel blockers that be used for a drug challenge?
Ajmaline, flecainide, procainamide, pilsicainide, disopyramide, propafenone
When is an epinephrine challenge helpful?
To diagnosed concealed LQTS
What imaging should be done in the workup of suspected arrhythmogenic RV?
MRI
What drug is commonly used in the EP lab to induce arrhythmia?
Isoproterenol
What type of testing is helpful in diagnosis and management of CPVT?
Exercise stress testing
Name 3 class IB antiarrythmics
- Phenytoin
- Lidocaine
- Mexiletine
What do the class IB antiarrhythmics do?
Na channel blocking with rapid recovery of blocked Na channel
What do class IB antiarrhythmics do the QT?
Slightly shorten it
Can you use phenytoin in LQTS patietns?
Yes- Class IB Na Channel blocker
Name 3 class III antiarrhythmics
- Amiodarone
- Sotalol
- Ibutilide
How do the class III anti-arrhythmic work?
Block K channels
What do the class III anti-arrhythmic do the the QTc?
Prolong it
Best option for symptomatic, but hemodynamically stable atrial flutter?
IV Diltiazem (will slow RVR and give relief of symptoms)
- Could also use B-blocker or sotalol
- Cardioversion not 1st line for a stable patient
What effect can flecainide have in atrial flutter?
Slow atrial conduction within flutter circuit and slow flutter rate (can convert fast flutter with AV block to slow flutter with 1:1 AV conduction)
What effect can disopyramide have in atrial flutter?
May enhance AV node conduction (worsen situation if used alone)
*Class I with anticholinergic activity
For atrial flutter, flecainide and disopyramide are best used in conjunction with what?
An AV nodal blocking agent
What drug is a Ca-sensitizing agent that binds to troponin C and improves contractile efficiency and reduces afterload?
Lecosimendan
What drug is a “L”-type CCB and reduces intacellular Ca by reducing Ca-induced Ca release?
Verapamil
What drug is a Na-K ATPase inhibitor and indirectly increases intracellular Ca?
Digoxin
MOA milrinone?
Phosphodiesterase 3 inhibitor
What drug is a synthetic BNP used to treat decompensated HF patients?
Nesiritide
What drug is useful in complete AV block?
Isoproterenol
*Can result in stable junctional/ventricular escape rhythm
How does isoproterenol work?
Stimulates myocardial B1 receptors…increased chronotropy and inotropy
How does atropine work in AV block?
Only works in reversing AV block due to excessive vagal effect…anticholinergic/vagolytic agent
Patient in low CO state with pulmonary edema due to severe MR… what drug is helpful to increase CO?
Nitroprusside
- Large % of LV SV going back to LA causing elevated LA pressure and pulmonary edema
- Needs systemic vasodilator to increase forward SV
How can anemia cause drop in SpO2 in a Tet?
- Get systemic vasodilation with anemia… more R-L shunting
- Increased tissue oxygen extraction… lower mixed venous saturation
Side effects of PGE1?
- Apnea
- Fever/hyperthermia
- Hypotension
- Seizures
- Cutaneous vasodilation
- Edema
What is a long-term side effect of PGE?
Cortical hyperostosis
What drug used in Marfan blocks TGF-B signaling?
Losartan
MOA Losartan?
Angiotensin receptor 1 antagonist (this antagonizes TGF-B signaling)
*Exact mechanism uncertain: Activation of angiotensin type 1 receptors increases expression of TGF-B ligands and receptors and induces activation of thrombospondin (powerful TGF-B activator)
What is Eplerenone?
Mineralocorticoid receptor (aldosterone receptor) antagonist
*Similar effects of spironolactone (hyperkalemia)
List 3 drugs that amiodarone increases levels of
- Cyclosporine
- Digoxin
- Warfarin
*Inhibits activity of cytochrome P450
What needs considered when putting a patient taking B-blocker on amiodarone?
Potential for heart block… due to AV nodal blocking effect of amiodarone
What is the primary effect of amiodarone?
Class III antiarrhythmic- primarily K channel blocker
*Prolongs repolarization and QTc interval
What are additional effects of amiodarone besides K channel blocking?
- Some degree CCB
- Blocks cardiac Na channels
- Produces B-blockade (causes reduced AV nodal conduction)
*NOT a vagolytic agent
What can exacerbate the pro-arrhythmic potential of amiodarone and can precipitate torsades de pointes?
Hypokalemia
Patients taking which medication, tacrolimus or cyclosporine have a higher instance of post-transplant diabetes?
Tacrolimus
Tacrolimus (8%)
Cyclosporine (2%)
Name 3 things that predispose to post-transplant diabetes
- Higher tacrolimus levels
- HLA-DR mismatch
- Older age at transplantation
Which post-transplant medication is associated with bone marrow suppression?
Sirolimus
*Especially when used with tacrolimus
True or False: Lipid abnormalities are common even in younger children who are heart transplant recipients and lipid-lowering therapy is often instituted in this subgroup
True
What 2 types of medication are typically used for managing HTN in pediatric heart transplant recipients?
CCB
ACEi
Which is less nephrotoxic… sirolimus, cyclosporine, tacrolimus?
Sirolimus
List drugs which lower PVR
- Tolazoline: Non-selective competitive alpha-adrenergic receptor antagonist
- Nitric oxide: NOT nitrous oxide
- Dobutamine
- Milrinone
- Prostaglandins
- Prostacyclins
- Sodium nitroprusside
- Sildenafil
*Ketamine may increase PVR
What might cause an acute drop in platelets in a post-op patient on heparin?
HIIT- Heparin induced thrombocytopenia with thrombosis
What is the pathophysiology of HIIT?
- Heparin combines with platelet factor 4 complex and makes it immunogenic
- Resulting antibodies to this complex may result in formation of platelet aggregates which can cause vaso-occlusion and cause immune-mediated platelet destruction resulting in thrombocytopenia (> 50% drop in plt count)
How is HIIT diagnosed?
- Specific antibody assay
* Once a thrombotic complication has occurred however, need urgent therapy even w/o diagnosis
How do you manage HIIT?
- Stop heparin
- Other form of anticoagulation
True or False: You often need a platelet transfusion with HIIT?
False: Platelet drop usually isn’t enough to cause clinically significant bleeding
What other form of anticoagulation isn’t used in HIIT?
LMWH (enoxaparin)
-May not provoke HIIT, but could cross-react with heparin antibodies and isn’t used in HIIT patients
Teratogenic effects of warfarin?
- Defects in calcification of epiphyses (chondrodysplasia puctata)
- Retarded intrauterine growth
- Psychomotor deficit
- Hypotonia
- Convulsions
- Nasal hypoplasia
- Ocular and CNS abnormalities
When is the risk of teratogenicity highest with warfarin use?
- 1st trimester (10%)- Critical period is between 6-9 weeks gestation
- Risk is estimated 3-5% during 2nd/3rd trimester
Teratogenic effect of Lithium?
Ebstein
Teratogenic effect of Amiodarone?
Thyroid issues (hypo or hyper)
Teratogenic effect of ACEi?
- Renal damage
- Cranial ossification defects
- Oligohydramnios
- Delayed intrauterine growth
Which trimesters is it especially important to avoid ACEi?
2nd/3rd
*But contraindicated during all of pregnancy
What is protective against neural tube defects?
High dose folic acid therapy
Symptoms of digoxin toxicity?
Dizzy, mild hypotension, high-grade AV block, significant ventricular ectopy including non-sustained VT
What should be done for high-degree symptomatic AV block due to digoxin toxicity?
- IV atropine
- Temporary pacing
What should be given for patients with serious signs of digoxin toxicity?
Digoxin antibody Fab
Besides digoxin antibody Fab, what else can be given to help with digoxin toxicity?
- Activated charcoal
- Cholestyramine
*Bind digoxin in the gut and help with GI elimination and increased systemic clearance
How is digoxin eliminated in the body?
50-70% via kidneys
*No significant hepatic contribution
What clinical history should you consider with digoxin toxicity?
-Any renal dysfunction, chronic or acute due to illness, dehydration, etc.
What electrolyte abnormality exacerbates digoxin toxicity?
Hyperkalemia
*Treating hyperkalemia is helpful as well
What can be given if a patient develops symptomatic ventricular arrhythmias due to digoxin toxicity and no digoxin antibody is available?
IV Lidocaine
What are 3 options for persistent post-operative HTN?
- Beta-blockers: Use with caution in asthma
- Nitroprusside: Use with caution in renal/hepatic dysfunction due to build up of cyanide
- Nicardipine (CCB): No adverse effects on the myocardium
What kind of drug is Precedex?
Selective alpha-2 receptor agonist
What sedative can cause a dose-dependent decrease in BP/HR from alpha 2 agonist effect on sympathetic ganglia with resultant sympatholytic effects?
Precedex
What can happen after relief of a distal fixed pulmonary valve obstruction?
Suicidal RV: Persistent dynamic infundibular/subpulmonary obstruction
*Severe subvalvular obstruction in absence of a distal fixed obstruction can cause complete or near complete RVOTO and lead to acute RV failure with poor RV filling and R-L shunt through PFO
What can be given to help with a suicidal RV?
IV beta-blocker
What are 2 drugs which may worsen a suicidal RV?
- Milrinone: Inotrope
2. IV Diuretics: Reduce RV preload
List potential side effects of statins
- Rhabdomyolysis (rare): Muscle pain, liver damage, kidney failure, death
- Diarrhea
- Liver damage
- GI problems (diarrhea or nausea)
- Rash/flushing
- Neurological side effects
What is the most common symptom associated with rhabdomyolysis due to stain use?
Muscle pain
What lab can help diagnose rhabdomyolysis due to statin use?
Creatine kinase (CK)
What are 2 induction agents for anesthesia which would cause a drop in SVR and be problematic for someone with complete mixing physiology?
- Inhaled anesthetic
2. Midazolam
What effects do inhaled anesthetic agents have on BP?
- Decrease BP due to vasodilation
* Variable impact on the CP system, but pose risk for hemodynamic compromise in a child with limited reserve
Which of the following has the least impact on BP: Halothane, isoflurane, sevoflurane?
Sevoflurane
What does ketamine do to SVR?
Increases
What can be given in combination with an inhaled anesthetic or midazolam to offset the vasodilatory effects?
Ketamine
Under what circumstance would it take a long time for an inhaled anesthetic like isoflurane to induce sedation?
- Someone with an shunt (PDA, BTT, etc.) and complete mixing physiology
- Isoflurane decreases BP due to vasodilation
- Decreased SVR increases R-L shunting
- A bigger R-L shunt reduces uptake of isoflurane from lungs, so longer time to achieve sedation
True or False: Isoflurane is a powerful bronchodilator and can even be used to break bronchospasm in life-threatening status asthmaticus
True
True or False: Bronchospasm doesn’t typically reduce uptake of inhalational anesthetic
True
Symptoms of B-blocker toxicity?
- Bradycardia
- Hypotension
- Hypoglycemia
What should be given for significant bradycardia due to beta-blocker toxicity?
Atropine (anticholinergic)
What should be given for hypotension due to beta-blocker toxicity?
- Atropine if bradycardic (increasing HR can help hypotension)
- IVFs
- Vasoactives
What should be given for hypoglycemia due to beta-blocker toxicity?
Glucagon
What things can increase warfarin effect (higher INR levels) and result in need to decrease warfarin dose?
- Amiodarone
- Levothyroxine
- Propranolol
- Sertraline
What supplement has been shown to decrease the efficacy of warfarin resulting in need for a higher dose?
St. John’s Wort
*Herbal supplement that can improve mood and treat depression
Do all babies with reflux need treated?
No… Babies that feed well despite regurgitation episodes, maintain weight gain and hydration and don’t experience significant irritability won’t require treatment
*All infants reflux
True or False: Research shows that acid suppression isn’t effective for alleviating reflux-related symptoms or regurgitation and irritability in infants
True
What can PPI and HR antagonists increase the susceptibility for?
Enteric infection
PNA
What are symptoms of withdrawal?
Anxiety, insomnia, restlessness, yawning, stomach cramps, rhinorrhea, diaphoresis, mydriasis, vomiting, diarrhea, fever, muscle spasms, tremor, tachycardia, hypertension, seizures
True or False: Delirium common in critically ill patients and can occur after even short periods of sedation
True
*In adults, benzodiazepines increase risk for delirium
What medication can reduce narcotic and benzodiazepine requirements and shorten the duration of mechanical ventilatino?
Precedex (dexmedetomidine)
*Also helps with anxiety and withdrawal symptoms during weaning
How does precedex work?
Centrally acting alpha-2 agonist
What effects does precedex have?
Anxiolytic, sedative, analgesic
*Doesn’t interfere with respiratory drive
What are potential side effects of precedex?
Hypotension/Hypertension
Bradycardia
A-fib
*Generally well tolerated
What medication can be given acutely in a pulmonary hypertensive crisis if the patient is intubated?
Paralytic- Vecuronium
- Paralytic + 100% O2 can help to reduce PVR
- Vec/Roc take effect within 120 seconds of administration
- Sedation is important, but doesn’t have immediate onset
At high doses, what does Epinephrine do to PVR?
Increases it
What can be given prior to suctioning or intubation to prevent laryngospasm?
Lidocaine
What effects does ketamine have?
Analgesia and sedation
*Doesn’t interfere with respiratory drive
What are 2 drugs used for sedation that can cause respiratory depression and increase risk for respiratory compromise?
Fentanyl and propofol
What are the effects of fentanyl?
Good analgesia
Inadequate sedation
What are 2 risks with ketamine?
Laryngospasm
Bronchorrhea
What are 2 things you should have available if using ketamine for sedation?
Muscle relaxant (laryngospasm) Glycopyrrolate or atropine (bronchorrhea)
What are symptoms of cyanide toxicity?
Metabolic acidosis
AMS
Bradycardia
Convulsions
What drug can cause cyanide toxicity in a post-op patient?
Sodium nitroprusside
*Especially with renal insufficiency
How often should cyanide levels be monitored in post-operative patients on sodium nitroprusside?
Every 72 hours (with prolonged use)
Treatment for cyanide toxicity due to sodium nitroprusside?
- Support airway, breathing, circulation
- Hydroxocobalamin
- Sodium thiosulfate
What conditions increase risk for cyanide toxicity when using sodium nitroprusside?
Hepatic impairment
Cardiopulmonary bypass
Therapeutic hypotermia
What can be given with nitroprusside to prevent cyanide toxicity?
Sodium thiosulfate
What type of anti-arrhythmic is flecainide?
IC
How does flecainide work?
Primarily a Na channel blocker- Prolongs phase 0 of action potential in the atrial myocardium, His-Purkinje system and ventricular myocardium
What are 2 changes that can be seen with Flecainide initiation?
- Increased QRS duration
- Lengthened PR interval
*Generally very little effect on QT interval, ST segments or T-waves unless toxic levels reached
What class antiarrhythmic is Procainamide?
IA
How does procainamide work?
Primarily blocks Na channels and K channels
What is the cardiac effect of procainamide?
- Slower conduction though atrial myocardium, His-Purkinje system, ventricular myocardium
- Little to no effect on sinus and AV node
What effect could procainamide have on atrial flutter with 2:1 conduction?
- Conduction through atrial muscle can slow this slows the atrial rate
- Slower atrial rate can change AV nodal conduction from 2:1 to 1:1
- This may increase ventricular rate and effect clinical status
What is diltiazem often used for?
- CCB
- Slows AV conduction during macroreentrant atrial arrhythmias
Name 2 class IB antiarrhythmics?
Lidocaine
Mexilitine
What is the effect of esmolol?
-Slowed conduction through AV node (BB)
What are 2 drugs which may be used in adults with IART and complex CHD with ventricular dysfunction who fail ablation and have no treatable precipitating factors?
- Amiodarone (use with caution if hepatic disease)
- Dofetilide
How is dofetilide excreted?
- Kidneys
* Need to dose adjust with renal disease
Which populations do you need to avoid flecainide in?
- Depressed ventricular function
- Complex CHD + Ventricular dysfunction
*Increased mortality
When is dronaderone not recommended?
- Heart failure
- Mod-severe systolic ventricular dysfunction
- Mod-complex CHD
*May worsen HF and increase mortality
What medication can be used for rate control in IART, but won’t maintain long-term sinus rhythm?
Metoprolol
What class is dofetilide?
III
How does dofetilide work?
Selectively inhibits the rapid component of the delayed rectifier K current
What do patients need to be monitored for when starting dofetilide?
QT prolongation and arrhythmia
*Risk of torsades
How is dofetilide excreted?
Kidneys
- Dose must be adjusted for impaired creatine clearance
- No effect on thyroid function
What are contraindications to Dofetilide?
- Creatine clearance <20
- Hypokalemia
- QTc >440 or >500 with ventricular conduction delay
What are the most common side effects of amiodarone?
- Hypothyroidism
- Hyperthyroidism
- Hepatitis (>2x normal AST/ALT- can progress to hepatic failure)
- Pulmonary toxicity (cough, fever, dyspnea, opacities on CXR, decreased DLCO on pulmonary function tests)
- Derm photosensitivity to UV light
- Blue-gray skin discoloration
- Corneal microdeposits (benign)
- Optic neuropathy
What medications do you need to be careful using in asthmatics?
- Non-selective BB (bronchospasm)
* Selective BB (like esmolol) should only act on beta 1 receptors, but still need to be cautious
What are 3 options for IV BP medications in a post-op patients with moderately controlled asthma?
- Nicardipine
- Clevidipine
- Hydralazine