A patient is admitted with complain of perforated peritonitis, laparotomy surgery is being conducted. What would be the reason behind the insertion of central line?

Appeared in: NORCET 3 - 2022 (Shift-1)

Explanation

A central venous catheter (central line) is placed into a large vein, with its tip resting in the superior vena cava, just above the right atrium.
This position allows for the direct measurement of Central Venous Pressure (CVP), which is a key indicator of the patient's intravascular fluid volume and right ventricular preload.
In conditions like sepsis from peritonitis and major surgery (laparotomy), massive fluid shifts occur, making CVP monitoring essential to guide fluid resuscitation and prevent both hypovolemic shock and fluid overload.
Other functions of a central line include administration of potent medications (vasopressors), parenteral nutrition, and drawing frequent blood samples, but CVP measurement is a primary hemodynamic monitoring purpose.

Option B: Systemic blood pressure is typically measured non-invasively with a sphygmomanometer (cuff) or invasively with an arterial line placed in an artery (e.g., radial artery), not a central venous line.
Option C: Pulse pressure is the mathematical difference between the systolic and diastolic blood pressure readings (SBP - DBP). It is a calculated value, not a directly measured one requiring a specific line.
Option D: A pulse deficit is the difference between the apical heart rate (auscultated with a stethoscope) and the peripheral pulse rate (palpated at a peripheral site like the radial artery). It is a manual assessment technique.

Clinical Relevance

Nursing practice connection: Use the key finding related to Indications for Central Venous Catheterization to guide bedside assessment, documentation, and the next nursing action.
Accurate CVP measurement is fundamental for goal-directed fluid therapy in septic shock, helping to optimize cardiac output and tissue perfusion while minimizing the risks of fluid overload.
Nurses are responsible for ensuring the CVP monitoring system is set up correctly, including leveling the transducer at the phlebostatic axis and zeroing the system, to obtain accurate readings.
What if? If the patient's CVP reading suddenly drops from 5 mmHg to 1 mmHg after a bout of coughing, the nurse should first check for equipment malfunction (e.g., loose connection, incorrect transducer level) and then assess the patient for signs of hypovolemia or hemorrhage, and notify the provider.

How to Approach the Question

First, analyze the clinical scenario: a patient with perforated peritonitis and laparotomy. Recognize that this patient is at high risk for sepsis and major fluid shifts.
Next, consider the intervention: insertion of a central line. Ask yourself, 'What are the primary functions of a central line in a critically ill patient?'
Evaluate the options based on the function of a central venous catheter.
Option A (CVP): Recall that CVP is a measure of fluid status/preload and is a primary reason for central line insertion in hemodynamically unstable patients.
Options B, C, D: Define each term. Realize that blood pressure is measured with a cuff or arterial line, pulse pressure is calculated, and pulse deficit is assessed manually. These do not require a central venous line.
Conclude that measuring CVP is the most logical and direct reason for central line placement in this specific clinical context.

Concept Tested & Keywords

Concept Tested: Indications for Central Venous Catheterization
Stem keywords: perforated peritonitis, laparotomy, central line
Lead-in keywords: reason behind
Clinical cues: Patient with perforated peritonitis and laparotomy suggests a high risk for sepsis and hemodynamic instability.

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E6 Medicine Harrison 22e Part 2 p. 197-199

Practise the full NORCET 3 - 2022 (Shift-1)

Attempt every question from this paper in a timed mock, then review the full solution for each one.