RCP 370 Ch. 7 Assessment of the Cardiovascular System

P wave

Depolarization of the atria

QRS complex

Depolarization of the ventricles

T wave

ventricular repolarization

how to calculate regular rhythm

- Count the number of large boxes on the ECG strip between two QRS complexes. Then 300 divided by large boxes (300/boxes).

- Count the wave and time by 10

Regular heart rhythm

300

Assessing HR boxes

- each small box is 0.2

- 3 sec = 15 boxes

- 6 sec = 30 boxes

Sinus Bradycardia

- <60 bpm

- Common causes: weakened or damaged SA node, hypoxemia, increased ICPs, OSA.

- Severe cases: decreased CO, BP, and tissue hypoxia.

- poor capillary refill, cold, clammy and depressed sensorium.

- Treatment: Atropine and oxygen

Sinus Tachycardia

- >100 bpm

- Common causes: severe anemia, hyperthermia, hemorrhage, pain, fever, anxiety, sympathomimetic or parasympathetic Drug Administration.

- Treatment: treat underlying cause, hypoxemia = administer oxygen therapy.

Atrial Flutter

Normal P wave are absent

and replaced by two or more

regular saw-tooth waves,

atria fires rapidly.

- Normal QRS complex

- Atrial rate is usually constant,

250-350 bpm

- Ventricular rate is in the

normal range

- Causes: hypoxemia, damage

to essay node and congestive

heart failure

- Treatment: Digoxin, beta

blockers, calcium channel

blockers.

Atrial Fibrillation

- Atrial contraction are disorganized (quivering).

- No visible P wave

- Atrial rate ranges from 350-700 bpm

- Atria is clot

- Causes: hypoxemia, damage to SA node also seen in OSA.

- Treatment: digoxin, beta blockers, calcium channel blockers, anticoagulants and thrombolytics.

Premature Ventricular Contraction (PVC)

- The QRS complex is wide, bizarre, and unlike the normal QRS complex Is not preceded by a P wave

- The regular heart rate is altered by a PVC. May be very irregular when there are many PVCs

- Common causes – Myocardial disease, hypoxemia, acidemia, hypokalemia, CHF. Also noted during theophylline, alpha stimulant and beta agonist toxicity.

- Treatment: oxygen, lidocaine

Bigeminal PVC

PVC after a normal heartbeat

Trigeminal PVC

PVC after q 2 heartbeats

Ventricular tachycardia (V-tach)

- P wave is not seen

- QRS complex = wide and bizarre

- Ventricular rate ranges from 150 to 250 bpm

- Blood pressure & LOC is often decreased during ventricular tachycardia -> medical emergency

- With pulse -> cardioversion, lidocaine, amiodarone

- Without a pulse -> defib, compressions, epinephrine & amiodarone

Ventricular Fibrillation

- Chaotic electrical activity and cardiac activity

- Ventricles quiver

- There is no perfusion beat-producing rhythm

- The is no cardiac output or blood pressure.

- The patient will die in minutes without treatment – CODE

BLUE

- Treatment: Defibrillation and CPR until ROSC

Asystole (Cardiac Standstill)

- The complete absence of electrical and mechanical activity

- Cardiac output stops, and the blood pressure falls to zero.

- The ECG tracing appears as a flat line

- Treatment: CPR and ACLS

Most Common Causes Of Cardiac Arrest

- Ventricular fibrillation

- Asystole

Hemodynamics

The forces that influence the circulation of blood

Invasive Cardiovascular Monitoring Assessments

- Invasive monitoring = assessment and treatment of critically ill patients.

(1) intracardiac pressures and flows via a pulmonary artery catheter

(2) arterial pressure via an arterial catheter (systemic) (3) central venous pressure via a central venous catheter

(4) coronary artery pathology (e.g., the use of the procedure coronary angiography

Systemic Arterial Catheter

The most commonly used mode of invasive hemodynamic monitoring

• Referred to as an a-line

• More accurate than cuff pressures

• Measures:

- Continuous systolic, diastolic, and mean arterial blood pressure

Fluctuations in blood pressure

- Data for guidance of therapy decisions for hypotension or hypertension ABG blood draws

CVP

2-6 mmHg

PAP (pulmonary artery pressure)

- 15-35/5-15

- 25/10

PCWP (pulmonary capillary wedge pressure)

4-12 mmHg

Cardiac Output (CO)

4-8 L/min

Stroke Volume

40-80 mL

Stroke volume index

40 ± mL/beat/m2

Cardiac Index

3.0 ± 0.5L/min/m2

Pulmonary vascular resistance

50-150 dynes × sec × cm-5

Systemic vascular

resistance

800-1500 dynes × sec × cm−5