A person breathes into and from a spirometer (volume 12 liters) containing 10% helium gas mixture. After equilibration, helium concentration of expired gas was found to be 6.67%. His ERV is 4.2 liters. What is his residual volume?

Correct Answer: C

Rationale: Residual volume (RV) is 1800 mL. Helium dilution: V1C1 = V2C2. V1 = 12 L, C1 = 10%, C2 = 6.67%. Total lung volume (V2) = V1 × C1 / C2 = 12 × 10 / 6.67 ≈ 18 L. At FRC (ERV + RV), he exhales ERV (4.2 L), so FRC = 18 - 12 = 6 L. RV = FRC - ERV = 6 - 4.2 = 1.8 L. C's 1800 mL unlike A's 1000 fits dilution math, per physiology.

Correct Answer: A

Rationale: Sputum cytology (A) is the primary diagnostic step for pulmonary carcinoma non-invasive, it detects malignant cells (e.g., squamous or adenocarcinoma) shed into airways, with 60-80% sensitivity if repeated. Chest x-ray (D) spots masses but isn't diagnostic alone lacks cellular detail. Bronchoscopy (C) visualizes and biopsies but follows suspicion. Gastric aspiration (B) is irrelevant lung cells don't migrate there. Scalene biopsy assesses metastasis, not initial diagnosis. Sputum's simplicity and specificity make it first-line, key in early detection, guiding imaging or invasive steps in oncology nursing protocols.

Correct Answer: D

Rationale: Bronchoscopy (D) is necessary for lung abscess diagnosis visualizes cavities, obtains cultures (e.g., anaerobes), rules out malignancy. Bronchography (A contrast imaging) is obsolete, replaced by CT. Pulmonary angiography (B) targets vessels, not abscesses. Photoscans (C likely perfusion scans) assess embolism, not infection. Pulmonary function gauges impact, not diagnosis. Bronchoscopy's direct sampling and imaging (CT adjunct) are gold standards, key in chest nursing for guiding therapy and excluding obstruction.

Correct Answer: A

Rationale: Superior vena caval syndrome (SVCS) SVC obstruction shows collateral vessels (A), dilated chest veins (e.g., from lung cancer compression). Tracheal perforation (B) is traumatic, unrelated. Elderly debilitation (C) isn't specific. Collaterals bypass blockage, key in nursing for recognizing malignancy-driven SVCS, prompting radiotherapy.

Correct Answer: C

Rationale: Vincristine, a vinca alkaloid, causes peripheral neuropathy, myopathy (C) microtubule inhibition affects nerves, muscles (e.g., foot drop). Myelosuppression (A) is methotrexate. Protein defects (B) fit asparaginase. Cystitis (D) is cytoxan. Psychosis is prednisone. Vincristine's neurotoxicity is key in nursing for dose monitoring and neuropathy assessment.