Interpretation and Clinical Examples

After invasive hemodynamic catheters are inserted, and the initial pressures and cardiac outputs are measured, maintenance of the patient is usually left to the critical care nurse. These tasks may include assessing the patient’s hemodynamic status, measuring and documenting pressures, and adjusting the vasoactive or inotropic drips as necessary. It is essential that the nurse have a clear understanding of how activity and pharmocologic intervention affect the hemodynamic status of the patient.

This portion of the module will use several case examples for practicing interpretation of hemodynamic pressures.

Case example 1

Mrs. Rainey, a resident of a skilled nursing facility, was found in her bed with a decreased level of consciousness, increased respirations, and a temperature of 102 degrees F. The SNF staff report that she had been suffering from vomiting and diarrhea for the past week. Mrs. Rainey was transferred to the ICU. A subclavian central line was placed and the physician ordered vital signs and CVP readings q2h, a fluid bolus of 500cc over 2 hours followed by a continuous IV of D51/2NS at 125cc/hr. A foley catheter was in place already. Urine was strong smelling, concentrated, and the hourly output was about 20cc/hr.

The following are Mrs. Raineys initial vitals signs prior to the fluid bolus:

and after the fluid bolus:

Interpretation:

Mrs. Rainey is hypotensive and tachycardic and her CVP indicates hypovolemia. A conservative fluid bolus gives her some additional volume without risking overhydration.

Case example 2

Mr. Felder is s/p "whipple procedure" and is in your ICU for post operative observation. He was transferred to you directly from the operating room with an arterial line in place in the left wrist and a triple lumen central line in the right subclavian. He is extubated and on O2 at 40% via face mask. You notice that Mr. Felder's arterial line waveform is dampened.

The following are Mr. Felder's vital signs:

Interpretation:

A dampened arterial waveform suggests that Mr. Felder's arterial line may be positional. His CVP, HR, and RR are all within normal limits. Nursing interventions included flushing the arterial line, repositioning Mr. Felder's wrist, and checking the arterial line reading with a cuff blood pressure.

Case example 3

Mr. Smyth was admitted to the ICU with epigastric pain and shortness of breath. A diagnosis of acute inferior myocardial infarction was made. While in the ICU, he developed cardiac dysrhythmias and experienced a decrease in blood pressure. A pulmonary artery catheter was inserted and 40% oxygen by face mask was applied. Drips of Lidocaine at 2 mg/min, and dobutamine at 8 mcg/kg/min were started. Urine output was marginal at 40 ml/hr. The following table contains some of the hemodynamic parameters obtained via the PA catheter.

Interpretation:

Mr. Smyth is normotensive and slightly tachycardic. His cardiac output and cardiac index are normal, but is PA pressures and PAWP are elevated. The dobutamine, an inotropic agent, strengthens cardiac contractions that subsequently support the CO and BP. This intervention sometimes results in vasoconstriction and could be responsible for the elevated PA pressures and SVR.

Case Example 4

Mrs. Jones was admitted to the ICU after an MVA for observation. During the first 24 hours she developed an increased heart rate and decreased BP. Her level of consciousness started to decrease and she was placed on 02 40% by face mask. A PA catheter was placed for evaluation of her fluid status. The follow table contains some of the parameters:

Interpretation:

Mrs. Jones is suffering from hypovolemic shock. The PA pressures and BP demonstrate a low fluid volume and increased HR reflects the compensation for this low volume. The SVR is also elevated as the body tries to constrict the blood vessels in order to compensate for the low fluid volume. Mrs. Jones may be suffering from internal bleeding and needs fluids immediately.