A nurse is reviewing the medical record of a client who has a prescription for intermittent heat therapy for a foot injury. Which of the following findings should the nurse identify as a contraindication for heat therapy?

A. "Morphine 3.0 mg sub q every 4 hr PRN for pain." Including a trailing zero (3.0 mg) is considered unsafe and is discouraged in medication documentation. It increases the risk of a tenfold overdose if the decimal is missed.
B. "Morphine 3 mg subcutaneous every 4 hr PRN for pain." This entry uses the correct dosage format without a trailing zero, the full term "subcutaneous" instead of abbreviations, and proper medical terminology. It adheres to safe documentation practices as per The Joint Commission guidelines.
C. "Morphine 3 mg SC q 4 hr PRN for pain." The abbreviation “SC” is considered unsafe and prone to misinterpretation. Also, "q" for "every" is discouraged in clinical documentation due to potential misreading and error.
D. "Morphine 3 mg SQ every 4 hr PRN for pain." The abbreviation “SQ” can be misinterpreted or mistaken for “5 every” or other terms. Safe practice requires spelling out “subcutaneous” to prevent errors in medication administration.

A. Respiratory rate 10/min. This is the priority finding because it suggests respiratory depression, a serious side effect of magnesium sulfate therapy. Magnesium acts as a CNS depressant, and a respiratory rate below 12/min is a potential sign of magnesium toxicity, which can lead to respiratory arrest if not promptly addressed.
B. 2+ deep-tendon reflexes. This indicates normal neuromuscular function and is actually a reassuring finding in a client receiving magnesium sulfate. Reflexes are typically monitored to detect early signs of toxicity, and a 2+ rating means the dose is likely therapeutic.
C. 3+ pedal edema. While significant, pedal edema is a common feature of preeclampsia and not directly related to magnesium sulfate toxicity. It should be monitored but does not require immediate action compared to respiratory compromise.
D. Urinary output 35 mL/hr. This is slightly above the minimum acceptable output of 30 mL/hr, indicating the kidneys are excreting adequately. While magnesium is excreted renally and output must be monitored, this value does not indicate an acute risk.