A nurse is caring for a client with stage III non-small cell lung cancer who is receiving chemotherapy. Which nursing intervention should be the priority to prevent complications during treatment?

Monitoring CBC daily is the priority to detect myelosuppression, a life-threatening complication of chemotherapy like cisplatin and etoposide. Other options address important but less urgent concerns.

Priority Nursing Intervention During Chemotherapy for Lung Cancer

The correct answer is to monitor complete blood count (CBC) daily.

Pathophysiological Rationale
The priority stems from the most common and dangerous dose-limiting toxicity of chemotherapy: chemotherapy-induced myelosuppression (CIM). Cytotoxic agents target rapidly dividing cells, a hallmark of cancer cells, but this mechanism is not selective. The bone marrow, with its high proliferative rate, becomes collateral damage. This results in the suppression of all three hematopoietic cell lines, a condition known as pancytopenia. The clinical consequences are directly linked to the three critical functions of blood: infection risk from neutropenia, bleeding risk from thrombocytopenia, and fatigue and tissue hypoxia from anemia. Monitoring the CBC provides a direct window into the functional reserve of the bone marrow and serves as the primary surveillance tool for these life-threatening complications [3,4].

Analysis of Answer Options

Option	Analysis and Evidence-Based Rationale
1. Monitor blood glucose levels every 4 hours	This is not a standard, high-priority intervention for all chemotherapy patients. While specific protocols involving high-dose corticosteroids as antiemetics can induce transient hyperglycemia, this is a secondary effect. The primary, life-threatening risk across nearly all myelosuppressive chemotherapy regimens is bone marrow suppression, not glycemic instability. This intervention is not supported as a general priority in the provided evidence on chemotherapy complications [1,2].
2. Encourage deep breathing exercises twice daily	This is a supportive, non-pharmacological intervention aimed at maintaining pulmonary function and preventing atelectasis, which is a component of comprehensive care. The MPNFS framework study highlights interventions to enhance pulmonary function, but these are part of a bundle to manage chronic effects like cancer-related fatigue, not the immediate, life-threatening complications of active treatment [1]. A patient with a critically low platelet count (e.g., < 20,000/mm³) is at risk for spontaneous pulmonary hemorrhage, a risk that deep breathing exercises do not address and could potentially exacerbate. The priority must be to first identify this risk through a CBC.
3. Assess skin integrity every shift	Skin assessment is a fundamental nursing function, but in the context of chemotherapy, it is secondary to myelosuppression monitoring. The primary risk to skin integrity from myelosuppression is not a local wound but the systemic risk of infection from a minor break in the skin when the patient is severely neutropenic (absolute neutrophil count < 500/mm³). The priority is to first determine if the patient is neutropenic via a CBC, which then dictates the intensity of skin and mucous membrane assessment and protective interventions.
4. Monitor complete blood count (CBC) daily	Correct. This is the priority intervention. The foundational risk of chemotherapy is CIM. Research consistently focuses on predicting and managing this toxicity because it dictates treatment continuation, dose adjustments, and survival outcomes. A study on gastric cancer patients established a direct association between nutritional status markers (like the Prognostic Nutritional Index, calculated from serum albumin and lymphocyte count from a CBC) and the incidence of myelosuppression [4]. Another study developed a machine-learning model specifically to predict CIM, underscoring its clinical significance as the primary toxicity requiring vigilant monitoring [3]. Daily CBC monitoring allows the nurse to detect a declining trend before the patient becomes critically pancytopenic, enabling preemptive interventions like administering colony-stimulating factors, initiating neutropenic precautions, or preparing for platelet transfusion.

Clinical Application and Synthesis
The nursing process mandates assessment as the first step, and in the context of chemotherapy, the most critical assessment is determining the patient's hematologic status. The psychological and pulmonary interventions described in the MPNFS and PERMA model-based studies are valuable for long-term quality of life and symptom management but are not the immediate safety priority [1,2]. A nurse's primary surveillance for a client receiving chemotherapy is to track the CBC, particularly the absolute neutrophil count (ANC), platelet count, and hemoglobin. The nadir, or lowest point of blood cell counts, typically occurs 7-14 days after administration, making daily monitoring during this period essential. This data directly informs all subsequent nursing actions, from implementing infection prevention protocols to assessing for signs of occult bleeding, thereby preventing the most common causes of chemotherapy-related morbidity and mortality.