# Stage 3 — Prioritize hypotheses. Mr. T, 64, had PCI with a drug-eluting stent yesterday for NSTEMI and receives aspirin, ticagrelor, a weight-based heparin infusion, and a morphine PCA (1 mg demand dose, 8-minute lockout, no basal infusion, patient-only activation). At 0200 he was drowsy but conversant with pain 3/10. At 0630, respirations are 10/min and shallow, SpO2 is 92% on 2 L/min, heart rate is 78 in sinus rhythm, and BP is 108/62 mm Hg, similar to overnight. Pain is 1/10. He arouses only to firm voice; pupils are 2 mm, equal, and reactive, and he moves all extremities. His wife says she pressed the PCA button while he slept; the pump shows 14 deliveries in four hours. The 0200 aPTT was 92 seconds (target 60 to 90), and there is no overt bleeding. Complete the diagram by selecting the condition the client is most likely experiencing, 2 actions the nurse should take to address that condition, and 2 parameters the nurse should monitor to assess the client's progress. > source: MyMerci (mymerci.kr) > url: https://mymerci.kr/pages/nclex_q.php?qn_id=617395&lang=en > language: en > subject: Adverse Effects/Contraindications/Interactions > category: PPT ## Question Stage 3 — Prioritize hypotheses. Mr. T, 64, had PCI with a drug-eluting stent yesterday for NSTEMI and receives aspirin, ticagrelor, a weight-based heparin infusion, and a morphine PCA (1 mg demand dose, 8-minute lockout, no basal infusion, patient-only activation). At 0200 he was drowsy but conversant with pain 3/10. At 0630, respirations are 10/min and shallow, SpO2 is 92% on 2 L/min, heart rate is 78 in sinus rhythm, and BP is 108/62 mm Hg, similar to overnight. Pain is 1/10. He arouses only to firm voice; pupils are 2 mm, equal, and reactive, and he moves all extremities. His wife says she pressed the PCA button while he slept; the pump shows 14 deliveries in four hours. The 0200 aPTT was 92 seconds (target 60 to 90), and there is no overt bleeding. Complete the diagram by selecting the condition the client is most likely experiencing, 2 actions the nurse should take to address that condition, and 2 parameters the nurse should monitor to assess the client's progress. Condition Select 1 Intracranial hemorrhage from anticoagulation Opioid-induced respiratory depression Recurrent myocardial ischemia with low output Expected sleep after effective pain relief Actions to take Select 2 Obtain a stat noncontrast head CT scan Increase oxygen and reassess at the next hourly round Stop the PCA, stay, and support his breathing Give a full 2 mg naloxone dose by rapid IV push Give titrated naloxone if breathing stays poor Parameters to monitor Select 2 Sedation level on the POSS Activated partial thromboplastin time Serum troponin End-tidal carbon dioxide Serum potassium ## Explanation Respirations of 10 and shallow, arousal only to firm voice, small reactive pupils, and pain 1/10 after the wife pressed the PCA while he slept indicate opioid-induced respiratory depression. The nurse stops the PCA, stays at the bedside supporting ventilation, and gives protocol-directed titrated naloxone if breathing remains inadequate. Sedation level and end-tidal CO2 show whether ventilation is recovering. ## In-depth explanation Quick answer Condition: opioid-induced respiratory depression. Actions: stop the PCA, stay, and support his breathing, and give titrated naloxone per protocol if breathing stays poor. Monitor: sedation level on the POSS and end-tidal carbon dioxide. Why this is correct The PCA is safe only because a sleepy patient stops pressing the button. When his wife pressed it for him, that safeguard was bypassed and 14 doses were delivered. Sedation rises before respirations fall, so increasing sedation with slow, shallow breathing, small pupils, and a very low pain score fits opioid excess. The first actions remove the source and protect breathing; naloxone is titrated in small doses so ventilation returns without causing severe pain or withdrawal. Sedation scores and capnography detect hypoventilation earlier than pulse oximetry, especially when the client is on oxygen. Easy analogy or mental picture A PCA is a self-closing tap: when the person holding it falls asleep, the water stops. Proxy dosing is someone else holding the tap open while the person sleeps. Memory hook Sleepy + slow + small pupils after PCA = stop, stay, support, then small naloxone doses. NCLEX decision rule For suspected opioid-induced respiratory depression, stop the opioid and support breathing first, then reverse with titrated naloxone. Monitor sedation and ventilation (capnography), not just SpO2. Why the other choices are wrong Intracranial hemorrhage is a real concern with heparin and dual antiplatelets, but his pupils are equal and reactive and he moves all extremities, so a stat head CT is not the first action and aPTT tracks anticoagulation rather than this problem. Recurrent ischemia with low output is excluded by a stable BP of 108/62 and sinus rhythm at 78, so troponin follows the wrong condition. Expected sleep is tempting because pain is controlled, but a rate of 10 with shallow breaths and arousal only to firm voice is not normal sleep. Adding oxygen and waiting an hour hides hypoventilation behind a normal SpO2. A full rapid 2 mg push is outdated for postoperative opioid patients because it can trigger severe pain, hypertension, and withdrawal. Serum potassium relates to the potassium infusion, a separate hazard. References 1ISMP — High-Alert Medications in Acute Care SettingsOpioids and PCA are high-alert; proxy activation is a recognized hazard 2DailyMed — Naloxone Hydrochloride Injection LabelingTitrated naloxone dosing for postoperative opioid depression ## Clinical scenario Case update 0630: slow shallow breathing, difficult arousal, small pupils, and low pain after family activated the PCA during sleep. ## Key concepts - **PCA by proxy** — Activation of a patient-controlled analgesia button by anyone other than the patient, which bypasses its safety design. - **POSS** — Pasero Opioid-Induced Sedation Scale, a nurse-rated sedation scale used to detect oversedation before respiratory depression. - **Capnography** — Continuous end-tidal CO2 measurement that detects hypoventilation earlier than pulse oximetry. ## Related questions - [A client is admitted to the emergency department after ingesting an unknown amount of acet…](https://mymerci.kr/pages/nclex_q.php?qn_id=362720&lang=en) - [A client with chronic heart failure is prescribed metoprolol 25 mg orally twice daily. 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