tachycardia, DKA, sepsis Flashcards
As a general rule, narrow-QRS complex tachycardias arise from ? while wide-QRS complex ones may be ? in origin
narrow: above the ventricles (SVT)
wide (0.12+): supraventricular or ventricular
regular rhythms with narrow QRS
Sinus tachycardia Atrial tachycardia AV nodal reentrant tachycardia (AVNRT) AV reentrant tachycardia (AVRT) Junctional tachycardia Atrial flutter
regular rhythms with wide QRS
V tach
Antidromic AVRT
Narrow complex tachycardia with aberrancy
irregular rhythms with narrow QRS
Atrial flutter with variable block
Afib
Multifocal atrial tachycardia
irregular rhythms with wide QRS
Polymorphic Vtach
Narrow complex tachycardia with aberrancy
If the tachycardic patient is unstable (as evidenced by ?), ? should be performed immediately
hypotension, pulmonary edema, AMS, or ischemic chest pain
synchronized cardioversion
In stable tachycardic patients, what should be done?
12-lead ECG should be obtained, and medical therapy can be initiated
important hx to get in tachy pts
time/circumstances surrounding symptom onset, duration of symptoms
PMHx: history of CAD, CHF, dysrhythmia, valvular disease, thyroid disease
current meds (including herbal or homeopathic regimens, OTC meds, and illicit drugs)
Fam hx: sudden cardiac death, dysrhythmia, other types of heart disease
physical exam in tachy pt may reveal underlying cause i.e.
pale mucous membranes with anemia; thyromegaly or goiter with thyrotoxicosis, barrel chest or nail clubbing with chronic lung disease
Vtach may be difficult to distinguish from ?
SVT with aberrant conduction
Certain factors favor VT, including ?
age 50+, history of CAD or CHF, history of VT, AV dissociation, fusion beats, QRS 0.14+ second, extreme left axis deviation, and precordial concordance (QRS complexes either all positive or all negative)
certain factors suggest SVT with aberrancy
age less than 35, history of SVT, preceding ectopic P waves with QRS complexes, QRS less than 0.14 second, normal or almost normal axis, and slowing or cessation of the arrhythmia with vagal maneuvers
If cannot distinguish between VT and SVT with aberrancy with certainty, how should you treat the pt?
as if VT is present
other tests to get in tachycardia
CXR: chamber enlargement, cardiomegaly, pulmonary congestion or edema
BMP: r/o electrolyte abnormalities that predispose to tachyarrhythmias (eg, hypokalemia, hypocalcemia, hypomagnesemia)
possibly:
thyroid function studies (for hyperthyroidism) drug levels (eg, digoxin) or UDS (for cocaine, methamphetamines, other stimulants)
Potential interventions for regular narrow-complex tachyarrhythmias
vagal maneuvers (such as carotid massage and Valsalva)- will not terminate tachyarrhythmias that do not involve the AV node, but may slow the rate enough to unmask the underlying rhythm abnormality adenosine, B-blockers, and CCBs
Stable patients with regular wide-complex tachycardias may benefit from ?
Second-line therapy for stable patients with monomorphic VT is ?
amiodarone, procainamide, or sotalol
(don’t need if non- sustained VT)
lidocaine
AV nodal blocking maneuvers
Valsalva, diving reflex, and carotid massage
they act through the parasympathetic nervous system
typical labs in moderate DKA
glucose: 500-700
Na+: 130 K+: 4-6
HCO3-: 6-10
BUN: 20-30 pH: 7.1 PCO2: 15-20 (compensating)
typical labs in severe DKA
glucose: 900+ Na+: 125 K+: 5-7 HCO3-: less than 5 BUN 30+ pH: 6.9 PCO2: less than 20 (resp. failure)
DKA dx based on triad of
hyperglycemia, ketosis, and metabolic acidosis
what other states present with elevated serum ketones?
how to ddx from DKA
starvation, pregnancy, alcoholic ketoacidosis, and various toxic ingestions (isopropyl alcohol ingestion)
glucose is normal/low
DKA triggers
most common?
infection is most common! (UTI)
pancreatitis, MI, stroke, and many drugs including corticosteroids, thiazides, sympathomimetics including cocaine, and some antipsychotic drugs
voluntary cessation of insulin (in kids/y. adults)
massive fluid deficits in DKA, how to tx?
often up to 5-10L
adults: 2L bolus of NS
kids: 20 mL/kg of NS
- reverse shock with NS, and then continue an infusion of 1/2 NS at 2-3x maintenance
how to give insulin in DKA
regular insulin by continuous IV infusion (0.1 U/kg/hr - about 5-10 U/h in adult)
(IV boluses work ok in adults, not for kids)
-will lower glucose faster than clearing ketones BUT continue insulin until anion gap has narrowed
when to add dextrose in DKA?
when glucose falls to 200-300 mg/dL
HCO3- in DKA?
complications?
when is it important to give
studies have failed to show improvements with treatment
complications: hypernatremia, hypokalemia, paradoxical CSF acidoses, systemic alkalosis
* lifesaving in hyperkalemia