Remember that the evaluate, identify, intervene sequence of the systematic approach algorithm is essential for the management of each system during the post-cardiac arrest phase.
The following goals and interventions for the cardiovascular system are carried out using this sequence from the systematic approach algorithm.
There are 3 goals that are included in cardiovascular management for immediate post-cardiac arrest care.
- Maintain adequate blood pressure.
- Maintain adequate cardiac output.
- Maintain adequate distribution of blood flow.
The purpose of the listed goals center around the need to maintain adequate tissue oxygenation and delivery of metabolic substrates to vital organs and tissues.
When addressing the cardiovascular system, the questions that need to be answered continuously during the evaluate sequence of the systematic approach algorithm are;
1. Is there adequate blood pressure?
2. Is there adequate cardiac output?
3. Is there appropriate distribution of blood flow?
These three questions are answered by assessments that are carried out. These assessments include continuous monitoring, physical examination, and medical tests.
- heart rate and rhythm
- blood pressure and pulse pressure (indwelling arterial blood pressure monitoring is the most reliable)
- O2 saturation by pulse oximetry
- 12 lead ECG: monitor for arrhythmias or evidence of myocardial ischemia
- Chest x-ray: evaluate heart size (An increased heart size can be an indicator of increased cardiac preload, congestive heart failure, or pericardial effusion)
Several other monitoring techniques can be used in the critical care setting if available. These include central venous pressure, central venous oxygen saturation, and cardiac output.
- peripheral and central pulses
- capillary refill
- extremity temperature and color
- urine output (urinary catheter)
- pupil reflexes
Note: Since end-organ function can be a good indicator of cardiovascular function, specific portions of the physical examination evaluate the end-organ function of other systems. For example, the evaluation of the end-organ function of the kidneys can be evaluated through the urine output and can be used in conjunction with other assessment parameters to provide a good indication of cardiac output.
- arterial and venous blood gas analysis
- hemoglobin and hematocrit
- chemistry panel: sodium, potassium, BUN, creatinine, calcium
If the continuous evaluations/assessments above indicate that the current interventions are adequate to maintain blood pressure, cardiac output, and appropriate distribution of blood flow, then the interventions will continue to be carried out.
If the continuous evaluation, at any time, indicates that the current interventions are inadequate to maintain blood pressure, cardiac output, or the appropriate distribution of blood flow then appropriate interventions will need to take place to correct the problem that is identified.
When providing post-arrest treatment for inadequate blood pressure, inadequate cardiac output, and maldistribution of blood flow, interventions will often have an effect on all three. For example, administration of fluid boluses will increase intravascular fluid volume which will in most cases increase blood pressure, improve cardiac output, and replace any maldistributed blood volume.
The initial cause of cardiac arrest will most likely determine what focus of treatment is implemented for the management of the cardiovascular system.
Treatment of Blood Pressure:
Adequate blood pressure is critical for the delivery of oxygen and nutrients to the tissues and organs.
An estimated adequate systolic blood pressure can quickly be obtained using this formula:
[2 x (age)] + 70] = low limit for an acceptable SBP.
Increase intravascular fluid volume:
If hypotension is caused by fluid loss or maldistribution then fluid volume replacement is indicated. Fluid volume should be replaced as needed to establish adequate intravascular fluid volume. Give 10-20 ml/kg boluses of isotonic crystalloid over 5-20 min and then reassess after each bolus. If heart failure is suspected or present small volume boluses of 5-10 ml/kg should be given. It is important to monitor for fluid volume overload in the presence of myocardial dysfunction or respiratory failure.
Treat hypotension with vasoactive medications:
If hypotension (low blood) pressure is caused by excessive vasodilation or if fluid volume replacement is not effective to normalize blood pressure then vasopressor medication is indicated. Such instances occur with certain types of shock such as anaphylactic shock and septic shock.
Again, quickly calculate the minimum normal blood pressure using this formula. [2 x (age)] + 70] = low limit for an acceptable SBP
Prevention of shock is critical to the management of the cardiovascular system in the post-cardiac arrest phase. (See Post-Arrest Shock overview)
Reduce metabolic demands:
During the post cardiac arrest phase, metabolic demands in the body can be greatly increased, this increases the consumption of oxygen and nutrients in the tissues and organs. The increased consumption of oxygen and nutrients can be detrimental in the post cardiac arrest phase, and efforts should be made to reduce metabolic demands. There are several interventions that can significantly reduce the metabolic demand placed on the body.
- intubation and assisted ventilation
- pain control
- fever control (antipyretics and therapeutic hypothermia)
Tachyarrhythmias and Bradyarrhythmias should be treated using the appropriate PALS algorithm.
Arrhythmias can have a significantly negative impact when they occur during the post cardiac arrest phase and should be aggressively treated.
Post-Arrest myocardial dysfunction:
There are a number of factors that commonly lead to myocardial dysfunction during the post-cardiac arrest phase.
If not recognized and aggressively treated, this post cardiac arrest myocardial dysfunction can lead to significant end organ damage and possibly another episode of cardiac arrest.
Myocardial dysfunction in the post arrest phase should be expected. When an insult to the myocardium occurs this affects its ability to perform effectively. Because of the dysfunction, cardiac output and ultimately tissue oxygenation can be negatively affected.
Treat myocardial dysfunction:
Common factors that can lead to myocardial dysfunction include metabolic abnormalities, hypotension, and compromised left ventricular function.
- Contractility issues:
During the post-arrest phase, myocardial dysfunction results in decreased contractility of the heart and also there may be an increase in the metabolic demands placed upon the heart. In light of this, the use of vasoactive medications is indicated.
- Metabolic abnormalities:
Most metabolic abnormalities can result in poor myocardial function and should be treated early in the post-arrest phase. Some of the most common abnormalities include acidosis, hypoglycemia, and hypocalcemia.
Hypotension can negatively affect all organ systems.
- Compromised left ventricular function:
In some cases positive pressure ventilation (PEEP) can be used to improve left ventricular function. This improved left ventricular function occurs as a result of PEEP increasing the plural pressure. This increased pleural pressure results in a reduction in afterload.
The identification and treatment of shock plays an important role in the management of the cardiovascular system during the post cardiac arrest phase. (Review Post-Arrest Shock here.)
(See management and treatment of shock)