63 Blood Sampling from a Pulmonary Artery Catheter 549

PROCEDURE Blood Sampling from a 63 Pulmonary Artery Catheter

Kathleen M. Cox PURPOSE: To obtain blood from the pulmonary artery (PA) catheter for determination of mixed venous oxygen saturation.

PREREQUISITE NURSING PATIENT AND FAMILY EDUCATION KNOWLEDGE • Explain the purpose for blood sampling to the patient and • Knowledge of anatomy and physiology of the pulmonary family. Rationale: Provision of information helps the patient and cardiovascular system is needed. and family make informed decisions, reduces anxiety, and • Understanding principles and performance of sterile and facilitates cooperation. aseptic technique and infection control is necessary. • Explain the patient ’ s expected participation during the • Physiological gas exchange and acid-base balance should procedure. Rationale: Discussion of the patient’ s partici- be understood. pation supports patient autonomy and sense of control and • Technique for specimen collection and labeling should be increases patient cooperation.1 known. • Principles of hemodynamic monitoring need to be understood. PATIENT ASSESSMENT AND • Knowledge about the care of patients with PA catheters PREPARATION (see Procedure 72) and stopcock manipulation (see Pro- cedure 75 ) is needed. Patient Assessment • The most frequent blood specimen obtained from the PA • Assess the patient ’ s cardiopulmonary and hemodynamic

is one for mixed venous oxygen saturation (Sv o2 ) analy- status, including abnormal lung sounds, respiratory dis- sis.9,10 tress, dysrhythmias, decreased mentation, agitation, and

• S v o 2 measures the oxygen saturation of the venous blood skin color changes. Rationale: These signs and symptoms in the PA (see Procedure 16 ). could necessitate blood sampling for venous oxygenation.

• S v o2 samples may be obtained to calibrate the equipment • Assess for a decrease in cardiac output related to changes when continuously monitoring Svo 2 values. in preload, afterload, or contractility. Rationale: Mixed • Routine blood sampling from the PA catheter is not rec- venous blood samples are used to evaluate changes in ommended because entry into the sterile system may cardiopulmonary function. increase the incidence of catheter-related infection. 2,6,7 • Assess the hemodynamic waveforms. Rationale: Deter- mines that the PA catheter is in the proper position. EQUIPMENT • Assess for a decrease in cardiac output related to changes in preload, afterload, or contractility. Rationale: Mixed • Nonsterile gloves venous blood samples are used to evaluate changes in • Goggles or fl uid shield face mask cardiopulmonary function. • Antiseptic solution (e.g., 2% chlorhexidine-based solution) • Needleless blood sampling access device (blood-transfer Patient Preparation device) • Verify that the patient is the correct patient using two • Two 10-mL syringes identifi ers. Rationale: Before performing a procedure, the • Blood-specimen tubes nurse should ensure the correct identifi cation of the patient • Blood gas sampling syringe for the intended intervention. • Needleless cap (injectable cap) or nonvented cap (nonin- • Confi rm that the patient and family understand preproce- jectable cap) dural teaching by having them verbalize understanding. • Laboratory form and specimen label Clarify key points by reinforcing important information • Specimen transport bag(s) and answer all questions. Rationale: Understanding of Additional equipment, to have available as needed, includes previously taught information is evaluated and reinforced. the following: • Position the patient so that the intended blood sampling • Additional syringes port is exposed. Rationale: Optimal positioning improves • Bag of ice the ease of obtaining the blood sample and reduces poten- • Sterile 4 × 4 gauze pad tial contamination of the port.

548 63 Blood Sampling from a Pulmonary Artery Catheter 549

Procedure for Blood Sampling from a Pulmonary Artery Catheter Steps Rationale Special Considerations 1 . HH 2 . PE 3. When drawing a mixed venous Prepares the ABG syringe. Heparin is usually in powdered form.

oxygen (Svo 2 ) sample, open the arterial blood gas (ABG) kit and expel the excess air and heparin from the syringe. 4. Temporarily suspend the PA Prevents the alarm from sounding alarms. because the PA waveform is lost during the blood draw. 5. PA distal stopcock: A. Remove the nonvented cap Prepares the line for blood sampling. (noninjectable cap) from the stopcock of the distal lumen of the PA catheter. or B. Cleanse the needleless cap Prepares the line for blood sampling Follow institutional standards. (injectable cap) at the top of and reduces the risk for infection. the stopcock of the distal lumen of the PA catheter with an antiseptic solution and allow to dry.2,4,7,8 (Level B * ) 6. Place a sterile syringe or a Prepares for blood sampling. needleless blood sampling access device (blood-transfer device) into the top port of the stopcock of the distal lumen of the PA catheter (see Figs. 62-1 and 63-1 ).

* Level B: Well-designed, controlled studies with results that consistently support a speciﬁ c action, intervention, or treatment.

Procedure continues on following page

O F F To patient To flush solution

Figure 63-1 A syringe attached to the port of the three-way stopcock. The stopcock is turned “off” to the port of the stopcock. (Drawing by Paul W. Schiffmacher, Thomas Jefferson University, Philadelphia, PA.) 550 Unit II Cardiovascular System

Procedure for Blood Sampling from a Pulmonary Artery Catheter—Continued Steps Rationale Special Considerations 7. Turn the stopcock off to the fl ush The syringe or needleless blood- solution (see Figs. 62-2 and sampling access device is then in 63-2 ). direct contact with the blood in the PA. 8. With a syringe, slowly and gently Clears the catheter of fl ush solution. If additional laboratory studies are aspirate the discard volume or, if The discard volume includes the dead needed, larger discard volumes may using a needleless blood- space (from the tip of the distal be necessary for accurate results.12 sampling access device, engage lumen to the top port of the the blood specimen tube to stopcock) and the blood diluted by obtain the discard volume. the fl ush solution (e.g., (Level B * ) 3.5 mL).2,3,5,10–12 9. Turn the stopcock off to the Stops blood fl ow and closes the top syringe or the needleless blood- port of the stopcock. sampling access device (see Figs. 62-1 and 63-1 ). 10. Remove the syringe or the blood Removes and safely disposes of the specimen tube and discard in the discard. appropriate receptacle. 11. Insert an ABG syringe into the Prepares for removal of a blood stopcock or insert the ABG sample. syringe into the needleless blood-sampling access device. 12. Turn the stopcock off to the fl ush Prepares for blood sampling. system (see Figs. 62-2 and 63-2 ).

*Level B: Well-designed, controlled studies with results that consistently support a speciﬁ c action, intervention, or treatment.

To F F patient O To flush solution

Figure 63-2 A syringe attached to the port of the three-way stopcock. The stopcock is turned “off” to ﬂ ush solution. (Drawing by Paul W. Schiffmacher, Thomas Jefferson University, Philadel- phia, PA.) 63 Blood Sampling from a Pulmonary Artery Catheter 551

Procedure for Blood Sampling from a Pulmonary Artery Catheter—Continued Steps Rationale Special Considerations

13. Slowly aspirate the Svo 2 sample Slow aspiration is important to (e.g., 1 mL). prevent contamination of the mixed venous sample with arterial blood from the pulmonary capillaries,

which will falsely elevate the Sv o2 value. 11 14. Turn the stopcock off to the Prevents bleeding. syringe or the needleless blood sampling access device (see Figs. 62-1 and 63-1 ). 15. Remove the ABG syringe. Detaches the specimen. 16. Expel any air bubbles from the Ensures the accuracy of the Sv o2 ABG syringe and cap the syringe. results. 17. Turn the stopcock off to the Prepares the system. patient. 18. Fast fl ush the remaining blood Clears blood from the system. from the top port of the stopcock: A. Remove the nonvented or noninjectable cap. B. Flush the blood onto a sterile gauze pad, into a discard syringe, or into a blood specimen tube. 19. Turn the stopcock off to the top Opens the system up for continuous Remove the needleless blood- port of the stopcock (see Figs. PA pressure monitoring. sampling access device if used. 62-1 and 63-1 ). 20. Attach a new sterile nonvented Maintains a closed sterile system. cap (noninjectable cap) or cleanse the needleless cap (injectable cap) with antiseptic solution. 21. Flush the remaining blood in the Promotes patency of the PA catheter. PA catheter back into the patient. 22. Observe the monitor for return of Ensures continuous monitoring of the the PA waveform. PA waveform. 23. Remove PE and discard used Reduces the transmission of supplies. microorganisms; Standard Precautions. 24. HH 25. Turn the alarms back on. Activates the alarm system. 26. Label the specimen and place in a Properly identifi es the patient and Confi rm identifying information. transport bag. Complete the laboratory tests to be performed. Label the blood-gas laboratory slip laboratory form. as a mixed venous sample. 27. Send the specimen for analysis. Needed for ABG analysis. Follow institutional policy regarding use of ice for ABG samples.

Expected Outcomes Unexpected Outcomes

• Adequate blood sample with minimal blood loss • Inability to obtain Sv o2 sample • PA catheter patency maintained • Clotting of the PA catheter

• S v o2 value and trends within normal range (60–80%) • Arterial sample obtained as a result of rapid withdrawal of blood from the pulmonary capillaries instead of mixed venous oxygen sample for blood- gas analysis Procedure continues on following page 552 Unit II Cardiovascular System

Patient Monitoring and Care Steps Rationale Reportable Conditions These conditions should be reported if they persist despite nursing interventions. 1. Before and after the blood Ensures that the PA catheter is • Abnormal PA waveforms or values withdrawal, assess and evaluate the properly positioned. PA waveform. 2. Correlate the Svo 2 results with the Changes in the Svo 2 indicate changes • Abnormal mixed venous oxygen measured cardiac output. in cardiac output and hemodynamic saturation, preload, afterload, status. cardiac output, and cardiac index 3. Correlate the Svo 2 results with the S v o2 decreases with: • Fever clinical assessment data. 2,10 • Increased oxygen consumption • Shivering • Decreased oxygen delivery • Seizures

Sv o2 increases with: • Agitation • Decreased tissue oxygen • Pain consumption • Decreased cardiac output • Increased oxygen delivery • Decreased hemoglobin • Decreased arterial oxygen saturation • Hypothermia

Documentation Documentation should include the following: • Patient and family education • Any difﬁ culties with PA catheter blood sampling

• Time and date of the Svo 2 sample • Nursing interventions performed • S v o2 results • Unexpected outcomes

References and Additional Readings For a complete list of references and additional readings for this procedure, scan this QR code with any freely available smartphone code reader app, or visit http://booksite.elsevier.com/9780323376624 .