Situation: A 64-year-old man who has smoked 1 pack of cigarettes a day for 40 years is admitted with newly diagnosed small cell lung cancer. Chemotherapy with cisplatin and etoposide is planned. Before his first dose, his complete blood count is within normal limits. Which baseline test should the nurse confirm has been done before cisplatin is started?

Cisplatin is ototoxic, causing cumulative high-frequency hearing loss and tinnitus, so a baseline hearing test is recorded and hearing is checked during treatment. Pulmonary function testing is for bleomycin, ejection fraction for anthracyclines and trastuzumab, and liver tests are critical before docetaxel.

Why audiometry before cisplatin

Cisplatin belongs to the platinum coordination complex group and exerts its antitumor effect by forming DNA cross-links, but the same reactive platinum species also damage cochlear outer hair cells. The resulting injury is ototoxicity, which typically presents as bilateral, symmetric, high-frequency sensorineural hearing loss that is dose-dependent and cumulative. Tinnitus often appears first and may be the only early warning sign. Because the damage begins in the basal turn of the cochlea, where high-frequency sounds are processed, routine conversation may remain intact while hearing loss is already progressing on audiometry.

For a patient about to receive the first cycle of cisplatin and etoposide, the nurse must verify that a baseline audiogram was obtained before treatment. This serves two purposes: it documents pre-existing hearing status, and it provides a reference point for detecting early changes during subsequent cycles. Key point! Once cisplatin-induced hearing loss occurs, it is generally irreversible, so prevention and early detection are the only realistic strategies.

Evidence from a randomized controlled trial in head and neck cancer patients receiving cisplatin-based chemoradiation confirms that cisplatin-induced hearing loss is frequent and severe, and that interventions such as trans-tympanic sodium thiosulfate gel are being studied specifically to prevent this ototoxicity ^[2]. The trial excluded patients with asymmetric hearing at baseline, which underscores why a pretreatment hearing assessment is essential before cisplatin exposure begins ^[2].

Why the other options are incorrect

Test	Primary drug concern	Relevance to cisplatin
Left ventricular ejection fraction	Anthracyclines (doxorubicin, daunorubicin), trastuzumab	Cardiotoxicity is not a defining cisplatin risk; routine baseline EF is not required for cisplatin alone
Serum bilirubin and liver enzymes	Docetaxel, other taxanes metabolized hepatically	Cisplatin is primarily nephrotoxic, not hepatotoxic; liver panels are not the priority baseline test
Pulmonary function tests	Bleomycin	Bleomycin causes interstitial pneumonitis and pulmonary fibrosis; cisplatin does not carry this specific pulmonary risk

Watch out! The distractors reflect classic chemotherapy-toxicity pairings. On licensure exams, each option is tied to a specific agent: anthracyclines to cardiac function, bleomycin to pulmonary function, docetaxel to hepatic function, and cisplatin to renal function plus hearing. Recognizing the drug-toxicity match is faster and safer than reasoning from the patient's lung cancer diagnosis alone.

For this patient with small cell lung cancer and a 40 pack-year smoking history, pre-existing hearing loss from smoking-related vascular damage or age-related presbycusis is possible. That makes baseline audiometry even more important, because it distinguishes treatment-related change from pre-existing deficits. The nurse should also anticipate monitoring serum creatinine and BUN before each cisplatin cycle, since nephrotoxicity is the other major dose-limiting toxicity, but the question specifically asks about the baseline test tied to ototoxicity, which is audiometry.