Pericardial diseases

Question 1

Bonus- Whats the IV dosing for midazolam? Oral?

Answer 1

IV- 1-2.5mg (max 5mg) as premed. 0.1-0.2mg/kg as induction agent.

Oral- 0.5mg/kg (max 20mg) as premed

Question 2

What is the pericardium

Answer 2

Sac surrounding the heart, composed of two layers

Visceral- thin, tissue like

Parietal- more rigid, fibrous layer

Question 3

How much fluid does the pericardial cavity hold

Answer 3

20-50ml

Question 4

What is the average pressure range within the pericardium? What does it vary with?

Answer 4

-4mmHg to 4mmHg

Respiration

Question 5

What does the pericardium do

Answer 5

Prevent infection

Lubricates the heart, facilitates motion within the sac

Prevents excessive heart displacement, maintains heart shape

Provides compensatory hydrostatic pressure to oppose alterations in gravity

Question 6

Bonus- What’s the dosing for ketamine? What is ketamine’s protein binding?

Answer 6

Induction- 0.5-2 mg/kg IV; sedation 0.2-0.5 mg/kg IV; maintenance- 1-2 mg/kg/hr IV; 5-10 mg/kg IM/PR

12% protein bound, low compared to the other induction agents

Question 7

Acute pericarditis patho and signs/symptoms

Answer 7

Inflammation of the pericardium, typically caused by viral infection, MI, or Dressler’s syndrome (believed to be an immune response post-myocardial trauma)

Sudden onset of severe chest pain made worse on INSPIRATION

DIFFUSE ST segment elevation, PR segment depression, T wave inversion

Pericardial friction rub

PAIN

Question 8

Acute pericarditis treatment

Answer 8

Salicylates/NSAIDS

Analgesics

Corticosteroids

Question 9

T/F

Acute pericarditis always alters cardiac function

Answer 9

F

Only in the presence of effusion is cardiac function altered

Question 10

What is pericardial effusion, signs/symptoms

Answer 10

Accumulation of fluid in the pericardial cavity, typically of idiopathic or neoplastic origin

Rate of fluid accumulation will determine symptoms. Acute increases are not well tolerated, while slow, chronic accumulations are often tolerated for a long period of time

Question 11

What is the main concern with an acute pericardial effusion

Answer 11

Cardiac tamponade can result from as little as 100ml of fluid rapidly accumulating in the pericardial cavity

Question 12

In chronic pericardial effusion how much fluid can accumulate before symptoms are noticed

Answer 12

Up to 1000ml, the slow rate of accumulation allows for the pericardium to stretch without a significant rise in pressure

Question 13

What is the most useful method for detecting and estimating the size of pericardial effusion

Answer 13

Echo

Question 14

What is impaired in cardiac tamponade

Answer 14

Diastolic filling

Filling is related to transmural pressure across the chamber, so even a small rise in pressure can impair diastolic filling (low pressure chamber)

Question 15

How can transmural pressure be calculated

Answer 15

Chamber pressure - extracavity pericardial pressure = transmural pressure

Question 16

Cardiac tamponade s/s

Answer 16

Increased CVP

Pulsus paradoxus ( >10mmHg drop in SBP during inspiration, pulse wave amplitude on A-line will also decrease)

Decreased CO, SV, BP

Decreased voltage on EKG

Increased SNS outflow

Tachypnea

JVD

Muffled heart sounds

Question 17

Tx for cardiac tamponade

Answer 17

Pericardiocentesis

Subxiphoid pericardiostomy

Thoracic pericardiostomy

Question 18

Anesthetic management in cardiac tamponade

Answer 18

Expand volume

Increase contractility (Isoproterenol)

Correct acidosis

Question 19

Bonus- What are the basic pharmacokinetics for propofol

Answer 19

Onset- 30 sec
DOA= short- redistributes in 2-8 min for wakeup
Vd- 3.5-4.5L/kg
E1/2- 0.5-1.5 hrs

Question 20

Constrictive pericarditis patho

Answer 20

Scarring/adhesions of the pericardium leads to a rigid, stiff shell around the heart. Impairs diastolic filling (heart cannot relax)

Can be caused by previous cardiac surg, radiation, TB. Also often idiopathic.

Question 21

Constrictive pericarditis s/s

Answer 21

CVP, RAP, PCWP increased
CO decreased
Fatigue
Atrial dysrhythmias 
Edema
Ascites
Hepatomegaly
Pulsus paradoxus 
JVD

Question 22

Tx for constrictive pericarditis

Answer 22

Pericardiectomy- removal of adherent/fibrous pericardium

Question 23

Anesthetic management for constrictive pericarditis

Answer 23

Minimize changes to HR, SVR, preload, and contractility (ketamine, etomidate, pancuronium)

Avoid bradycardia

Avoid hypotension (ensure large bore IV available for volume)

May need blood transfusions for pericardiectomy

Question 24

Bonus- What are the pKas for Lidocaine, Bupivacaine, and Chloroprocaine?

Answer 24

Lidocaine 7.9

Bupivacaine 8.1

Chloroprocaine 8.7 (but still fast onset time…)

Closer to 7.4 the faster the onset in general