Transcript
Chapter 12: Determinants and Assessment of Cardiac Output
Critical Thinking Checkpoint Case Studies
Case Scenario: Mrs. C. is a 75-year-old patient who underwent a left total hip replacement today. Her past medical history is positive for obesity and myocardial infarction (3 years ago). Six hours after her surgery, she began to experience shortness of air. Crackles are heard throughout her lung fields. Her oxygen saturation by pulse oximetry, on 2 liters nasal cannula, had been 95%, but now is 88%.
This activity contains 4 questions.
1. What additional physical assessment data do you need at this time?
Answers: You would want to collect the following additional assessments: Obtain vital signs. Make sure pulse oximeter is correctly placed and giving accurate data.
Obtain additional subjective data: Ask the patient if she is having chest pain. Is she coughing up sputum? Does she feel like she has to work to get air in or out?
Auscultate heart sounds, assess capillary refills. Is she using accessory muscles for ventilation? Does she appear to have increased work of breathing? Does she have JVD?
Assess extremities, skin color, temperature, pedal pulses, and presence of edema.
Assess intake and output (intraoperative and postoperative amounts).
2. Clinical Update: You complete your focused assessment.
BP 150/80 mm Hg (within her baseline), pulse 100 bpm, slightly weak and irregular, respiratory rate is 28 bpm. Pulse oximeter is reading 88% on 2 liters nasal cannula. Probe is properly placed.
She denies having chest pain. She is not coughing up sputum. She states that she feels like she can't get in enough air. She appears to have significant increased work of breathing and is using her accessory muscles of inspiration.
Auscultation of heart sounds reveals S1, S2, S3. Capillary refill is 3 seconds. JVD is elevated 4 cm above the sternal angle while at 45 degrees.
Assessment of her extremities reveals they are cool to the touch, pink, pedal pulses +2 bilaterally, and 3+ non-pitting edema is present.
Intake and output (intraoperative and postoperative amounts): total 10,000 mL intake; 2,000 urine output.
What are some abnormal findings based on her history and physical and what is your interpretation of these findings?
Answers: The abnormal findings based on her history and physical (with interpretation) include:
Past medical history of MI means her heart already has decreased contractility.
Cool skin, brought about by vasoconstriction of arteries as blood is shunted from skin to internal organs (caused by decreased cardiac output)
Delayed capillary refill is often associated with decreased cardiac output. However, it is not always useful as a marker of hypovolemia and myocardial function in the older adult.
Intake significantly greater than output. She received a lot of fluid intraoperatively. Theoretically, a decrease in CO causes a decrease in urine output. But there are other conditions and compensatory mechanisms that could cause decrease urine output
Peripheral edema may indicate too much preload to the right side of the heart. Crackles in the lungs also could be the result of pulmonary edema.
Positive JVD indicates too much preload to the right side of the heart. Retention of blood in the right side of the heart will increase right atrial pressures and subsequently produce JVD as a result of backflow of blood through the vena cava.
Weak pulse can be due to decreased cardiac output from a variety of causes, such as dysrhythmias or damaged myocardium.
S3 is caused by decreased ventricular compliance and may be a sign of early heart failure.
Shortness of air results from fluid movement out of the pulmonary capillaries and into interstitial spaces, thereby decreasing oxygen diffusion from the alveoli into the pulmonary capillaries.
Crackles are indicative of pulmonary edema.
3. Based on your focused assessment, what health problems, if any, do you suspect? Provide data to support your decision.
Answers: Based on your focused assessment, you would suspect the following:
The patient has excess preload, which has caused decreased stroke volume and impaired pulmonary gas exchange.
Problem: excess preload
Supporting data:
Intake greater than output
Crackles
Peripheral edema
Elevated JVD
S3
Weak pulse
3+ non-pitting edema
Problem: decreased stroke volume
Supporting data:
History of MI (poor contractility)
Cool skin
Delayed capillary refill
Weak, irregular pedal pulses
Cool extremities
Problem: impaired pulmonary gas exchange
Supporting data:
Use of accessory muscles of inspiration
Low oxygen saturation
Complaint of shortness of breath
Increased respiratory rate
Increased work of breathing
Crackles in lung fields
4. What additional cardiovascular diagnostic procedures might the nurse anticipate that the HCP will order?
Answers: Additional cardiovascular diagnostic procedures that the nurse can anticipate might be ordered by the HCP include:
Troponin: May indicate whether patient has had another MI. Even though she is 2 hours postop, she may have had an intraoperative MI.
BNP: When present in the serum, can indicate heart failure.
CXR: May view size and position of heart; visualize pulmonary edema.
ECG: Helps to evaluate for conduction abnormalities, as her pulse is irregular.
