# A nurse is caring for a patient with acute kidney injury (AKI) who has been receiving continuous renal replacement therapy (CRRT) for 48 hours. The nurse notes that the patient's CRRT circuit has decreased blood flow rates and increased pressures in the filtration system. Which assessment finding would require the most immediate nursing intervention?

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## 문제

A nurse is caring for a patient with acute kidney injury (AKI) who has been receiving continuous renal replacement therapy (CRRT) for 48 hours. The nurse notes that the patient's CRRT circuit has decreased blood flow rates and increased pressures in the filtration system. Which assessment finding would require the most immediate nursing intervention?

The nurse notes that the patient's CRRT circuit has decreased blood flow rates and increased pressures in the filtration system.

## 보기

1. Blood pressure 85/50 mmHg with weak peripheral pulses and cool extremities **✔ 정답**
2. Serum potassium level of 5.8 mEq/L reported from morning laboratory results
3. Urine output of 15 mL over the past 4 hours with dark amber coloration
4. Temperature of 100.8°F (38.2°C) with mild confusion and restlessness

**정답: 1**

## 해설

Hypotension (85/50 mmHg) with signs of poor perfusion requires immediate intervention to prevent cardiovascular collapse and further kidney damage in AKI patients on CRRT. Other findings are concerning but less immediately life-threatening.

## 심화 해설

Clinical Context

The patient is undergoing continuous renal replacement therapy (CRRT) for acute kidney injury (AKI). The nurse has identified a mechanical complication: decreased blood flow rates and increased filtration pressures in the CRRT circuit. This scenario signals an impending or ongoing circuit clotting event, which threatens the delivery of prescribed therapy. The immediate nursing priority is to assess for and manage the most life-threatening consequence of a circuit malfunction, which is often related to the underlying need for effective anticoagulation and the patient's hemodynamic tolerance of the procedure.

Correct Answer Analysis (Option 1)

A blood pressure of 85/50 mmHg with weak peripheral pulses and cool extremities is the finding requiring the most immediate intervention. This clinical picture represents hemodynamic instability and hypoperfusion. In the context of a CRRT circuit with rising pressures, this is a critical alarm. The increased circuit pressures often indicate significant clot formation within the filter. If the circuit clots completely, the patient experiences an acute loss of blood volume trapped in the extracorporeal system, which can precipitate or worsen hypotension. More importantly, the hypotension itself will further reduce the blood flow through the circuit, accelerating stasis and clotting, creating a vicious cycle. The nurse must immediately intervene, which typically involves pausing therapy, administering a fluid bolus, and preparing to return the circuit blood or replace the clotted system, as the patient's perfusion is compromised. The foundational principle of CRRT management, as highlighted in the literature on specialized nursing care, is the prevention and rapid response to hemodynamic complications, as they are a primary cause of unplanned interruptions and adverse outcomes [3,4].

Incorrect Answer Analysis

Option 2

A serum potassium level of 5.8 mEq/L is a significant finding indicating hyperkalemia, a common and dangerous complication of AKI. While this requires prompt intervention, it is not the most immediate priority in this specific situation. The CRRT is the very treatment intended to correct this electrolyte imbalance. The immediate threat to life is the patient's hemodynamic collapse, which will prevent the CRRT from being delivered effectively. Addressing the hypotension and circuit failure is the prerequisite to continuing the therapy that will manage the hyperkalemia. The management of electrolyte disturbances is a core component of CRRT, but it is secondary to stabilizing a crashing patient .

Option 3

A urine output of 15 mL over the past 4 hours with dark amber coloration is an expected finding in a patient with severe AKI requiring CRRT. Oliguria or anuria is the clinical hallmark of the disease process that led to the initiation of renal replacement therapy. This finding represents the patient’s underlying renal failure status and does not represent an acute change or a direct complication of the malfunctioning CRRT circuit. It requires ongoing monitoring but no immediate intervention beyond the established treatment plan .

Option 4

A temperature of 100.8°F (38.2°C) with mild confusion and restlessness could indicate an infection, possibly related to the central venous catheter used for CRRT. While a catheter-related bloodstream infection is a serious concern that requires investigation, it does not pose the same imminent threat to life as the acute hemodynamic instability caused by a clotting circuit. The confusion and restlessness may also be a direct symptom of cerebral hypoperfusion from the low blood pressure, making the hypotension the primary problem to correct. The priority is to first stabilize the patient's circulation before conducting a full infectious workup [3].References (research sources)

- [3]Specialized nursing improves clinical outcomes in pediatric AKI patients undergoing CRRT: a retrospective cohort study.Research articleZhang H, Li B, Guo H, Yi D, He Q. (2026) · DOI: 10.62347/wgqu7732

## 임상 시나리오

CRRT Circuit Malfunction: Clinical Triage

When CRRT circuit pressures rise and blood flow drops, the primary threat is circuit clotting. The nurse's immediate priority is to assess the patient's hemodynamic status, as this dictates the urgency and type of intervention.

**Immediate Action for Hemodynamic Instability:** If the patient presents with hypotension (e.g., SBP < 90 mmHg), weak pulses, and signs of shock, **stop the CRRT pump immediately**. Do not return the blood from a potentially clotted circuit, as this can cause thromboembolism. Initiate a rapid fluid bolus as prescribed, place the patient in Trendelenburg position, and notify the provider for emergency orders.

1. Assess the Patient First, Then the Machine

- **Primary Survey:** Check airway, breathing, and circulation (ABCs). Obtain a manual blood pressure and assess peripheral pulses, capillary refill, and mental status.

- **Vital Sign Trend:** Compare current vitals to previous readings. A sudden drop in blood pressure is a red flag for acute blood loss into the circuit or a new underlying event (e.g., sepsis, bleeding).

2. Interpret the Circuit Alarms

- **Rising Transmembrane Pressure (TMP) and Venous Pressure:** Classic indicators of filter and/or venous air trap clotting.

- **Decreased Blood Flow Rate:** Often a consequence of increased resistance from clot formation or kinked tubing. Do not simply increase the pump speed without investigating the cause.

3. Prioritize Life-Threatening Findings

- **Hypotension with Hypoperfusion (Option 1):** This is the highest priority. It signals cardiovascular collapse, which can be exacerbated by circuit clotting and blood loss.

- **Hyperkalemia (Option 2):** A K+ of 5.8 is urgent but typically managed with medical therapies (e.g., calcium gluconate, insulin/glucose) after stabilizing circulation. The CRRT will address it, but only if the patient is perfusing.

- **Oliguria (Option 3):** Expected in AKI. Not an acute change requiring immediate intervention.

- **Fever/Confusion (Option 4):** Suggests infection; requires workup (blood cultures, antibiotics) but is secondary to managing shock.

**Key Safety Point:** A clotted CRRT circuit in a hypotensive patient is a dual emergency. The loss of the extracorporeal blood volume worsens shock, and the shock state promotes further clotting. Always prioritize restoring the patient's hemodynamics over salvaging the circuit.

## 핵심 개념

- **Continuous Renal Replacement Therapy (CRRT)** — A slow, continuous form of dialysis used for hemodynamically unstable patients with acute kidney injury, running 24 hours a day to remove fluid and solutes.
- **Circuit Clotting** — A common complication of CRRT where blood clots form within the extracorporeal tubing or filter, indicated by rising transmembrane and venous pressures and decreased blood flow.
- **Hemodynamic Instability** — A state of inadequate blood flow and oxygen delivery to tissues, often manifested by hypotension, tachycardia, weak pulses, and cool extremities.
- **Hypoperfusion** — Decreased blood flow through an organ or tissue; in shock, it leads to cellular dysfunction and is a sign of a life-threatening emergency.
- **Extracorporeal Circuit** — The blood pathway outside the patient's body in therapies like CRRT, including tubing, the filter, and the blood pump.

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