Blood Sampling from a Pulmonary Artery Catheter
PREREQUISITE NURSING KNOWLEDGE
• Knowledge of sterile technique is needed.
• Knowledge of cardiovascular and pulmonary anatomy and physiology is necessary.
• Gas exchange and acid-base balance should be understood.
• Technique for specimen collection and labeling should be known.
• Principles of hemodynamic monitoring need to be understood.
• Knowledge about the care of patients with pulmonary artery catheters (see Procedure 73) and stopcock manipulation (see Procedure 76) is needed.
• The most frequent blood specimen obtained from the pulmonary artery is one for mixed venous oxygen saturation (SvO2) analysis.
• SvO2 measures the oxygen saturation of the venous blood in the pulmonary artery (see Procedure 16).
• SvO2 samples are obtained to calibrate the equipment when continuously monitoring SvO2 values.
• Routine blood sampling from the pulmonary artery catheter is not recommended because entry into the sterile system may increase the incidence of catheter-related infection.
EQUIPMENT
• Goggles or fluid shield face mask
• Needleless blood sampling access device
Additional equipment to have available as needed includes the following:
Rationale: Teaching provides information and may reduce anxiety and fear.
Rationale: This explanation encourages patient assistance.PATIENT ASSESSMENT AND PREPARATION
Patient Assessment
• Assess the patient’s cardiopulmonary and hemodynamic status, including abnormal lung sounds, respiratory distress, dysrhythmias, decreased mentation, agitation, and skin color changes. 
Rationale: These signs and symptoms could necessitate blood sampling for venous oxygenation.
• Assess for a decrease in cardiac output related to changes in preload, afterload, or contractility. 
Rationale: Mixed venous blood samples are used to evaluate changes in cardiopulmonary function.
Patient Preparation
• Verify correct patient with two identifiers. 
Rationale: Prior to performing a procedure, the nurse should ensure the correct identification of the patient for the intended intervention.
• Ensure that the patient understands preprocedural teaching. Answer questions as they arise, and reinforce information as needed. 
Rationale: Understanding of previously taught information is evaluated and reinforced.
• Position the patient so that the stopcock for blood sampling is exposed. 
Rationale: This positioning improves the ease of obtaining the blood sample and minimizes the contamination of the stopcock.
References
1. Carlson, KK, et al. Obtaining reliable plasma sodium and glucose determinations from pulmonary artery catheters. Heart Lung. 1990; 19:613–619.
2. Casey, AL, et al. A randomized, prospective clinical trial to assess the potential infection risk associated with the PosiFlow needleless connector. J Hosp Infection. 2003; 54:288–293.
3. Krueger, KE, et al. The reliability of laboratory data from blood samples collected through pulmonary artery catheters. Arch Pathol Lab Med. 1981; 105:343–344.
4. O’Grady, NP, et al, Guidelines for the prevention of intravascular catheter-related infections . Am J Infect Control. 2002; 30(8):476–489.
5. Palermo, LM, Andrews, RW, Ellison, N. Avoidance of heparin contamination in coagulation studies drawn from indwelling lines. Anesth Analg. 1980; 59:222–224.
