Identify the characteristics of normal and abnormal waveform pressures for the following hemodynamic monitoring parameters:
Describe the basic elements of hemodynamic pressure-monitoring equipment and methods used to ensure accurate pressure measurements.
Discuss the indications, contraindications, and general management principles for the following common hemodynamic monitoring parameters:
Describe the use of SvO2/ScvO2 monitoring in the critically ill patient.
Describe the use of functional hemodynamic measures including analysis of arterial waveform variation during positive pressure ventilation and passive leg raise test.
Compare and contrast the clinical implications and management approaches to abnormal hemodynamic values.
Explain the basic elements of minimally invasive hemodynamic monitoring techniques and the application of functional hemodynamics.
The term hemodynamics refers to the interrelationship of blood pressure (BP), blood flow, vascular volumes, heart rate (HR), ventricular function, and the physical properties of the blood. Monitoring the hemodynamic status of the critically ill patient is an integral part of critical care nursing. It is essential that critical care nurses have a working knowledge of how to obtain accurate data, analyze waveforms, and interpret and integrate the data.
Clinical examination findings such as mental status, urine output, edema, capillary refill, and jugular venous distension provide some data about a patient’s fluid balance, oxygenation, and blood flow. Additional data can be obtained through invasive hemodynamic monitoring and through functional hemodynamic assessment. Parameters such as arterial BP, cardiac output (CO), pulmonary arterial pressure (PAP), and intracardiac pressures can be directly measured and monitored with special indwelling catheters. Less invasive evaluations including the passive leg raise (PLR) test, cardiovascular ultrasound, and analysis of changes in the arterial waveforms in patients on positive pressure mechanical ventilation can also provide information about the patient’s fluid balance that guides management. Understanding how to gather hemodynamic data and interpret it is an essential function of the critical care nurse.
Cardiac output (CO) is the amount of blood pumped by the ventricles each minute. It is the product of the HR and the stroke volume (SV) which is the amount of blood ejected by the ventricle with each contraction. See Figure 4-1.
Factors affecting CO. (Reproduced with permission from Price S, Wilson L. Pathophysiology: Clinical Concepts of Disease Processes. Philadelphia, PA: Mosby; 1992.)
The normal value of cardiac output is 4.0 to 8.0 L/min (Table 4-1). It is important to note that these values are relative to size. Values within the normal range for a person 5-ft tall weighing 100 lb, may be totally inadequate ...