Section 37.5: Real Case Studies: Near Misses, Root Causes, and Prevention Protocols

37.5.1 The “Why”: Learning from Failure

In aviation, every crash or near-miss is investigated with forensic intensity, not to punish the pilots, but to understand the systemic failures that led to the event. The findings are then shared across the entire industry to prevent the same tragedy from happening again. This is the core principle of a high-reliability organization, and it is the model we must adopt in healthcare. Studying medication errors is not an exercise in blame; it is a profound opportunity to learn. By deconstructing real-world failures, we can see how the theoretical risks we’ve discussed—confirmation bias, poor labeling, inadequate double-checks—manifest as tangible patient harm.

A single case study is more powerful than a thousand warnings. It transforms abstract rules into a memorable story, connecting the dots between a seemingly minor system flaw and a catastrophic outcome. In this section, we will move from theory to reality. We will act as medication safety investigators, performing a Root Cause Analysis (RCA) on several classic error scenarios. Our goal is to identify the “holes in the Swiss cheese”—the multiple latent and active failures that had to align for the error to reach the patient. By understanding the anatomy of these failures, we can learn how to build more resilient systems and, as pharmacists, become more effective advocates for a culture of safety.

37.5.2 Case Study #1: The PCA Overdose

Layer of Defense	Latent Failure (The “Hole in the Cheese”)	Active Failure (The Human Error)
1. CPOE System Design	The dropdown list for opioids did not use Tall-Man lettering. “Morphine” and “HYDROmorphone” appeared as visually similar options close to each other. The system also lacked a hard-stop alert for high-dose opioid orders in opioid-naïve patients.	The resident, moving quickly, clicked on the wrong drug name due to confirmation bias.
2. Pharmacy Verification	High workload and pressure to verify orders quickly. Lack of a mandatory “hard stop” checklist for all PCA orders, especially those with basal rates.	The pharmacist failed to recognize the clinical red flags: a massive hydromorphone dose and the presence of a basal rate in an opioid-naïve patient. They processed the order without questioning it.
3. Nursing Administration & Double-Check	The hospital policy for a PCA double-check was weak, requiring only a “second glance” rather than a true independent verification.	The primary nurse programmed the pump. The second nurse performed a cursory check, trusting the first nurse and the pharmacist’s verification, and did not independently recalculate or question the dangerously high dose.
4. Patient Monitoring	The unit was busy, and staffing was tight. Post-op patients were not on continuous pulse oximetry or respiratory monitoring unless they had other risk factors.	The patient’s escalating sedation and decreasing respiratory rate went unnoticed for several hours between routine nursing checks.

Prevention Protocols Implemented After the Event

After a full RCA, the hospital implemented the following systemic changes:

• CPOE System Overhaul:
  • All opioid names were updated to use Tall-Man lettering (e.g., HYDROmorphone).
  • A hard-stop alert was built. Now, any new PCA order for an opioid-naïve patient that includes a basal rate requires the prescriber to enter a reason and acknowledge the risk.
  • Dose range limits were tightened, triggering an alert for any single hydromorphone dose over 0.5 mg.
• Pharmacy Workflow Redesign:
  • A mandatory, electronic checklist was added to the pharmacy verification step for all PCA orders. The pharmacist must now explicitly document the patient’s opioid status (naïve vs. tolerant) before the order can be released.
• Nursing Policy Change:
  • The PCA double-check procedure was redefined as a true independent double-check. The second nurse must now independently review the order and the pump settings before the pump is started. Both nurses must sign off in the MAR.

37.5.3 Case Study #2: The Vecuronium ADC Mix-Up

Layer of Defense	Latent Failure (The “Hole in the Cheese”)	Active Failure (The Human Error)
1. Pharmacy Storage & ADC Configuration	CRITICAL FAILURE: A neuromuscular blocker (vecuronium) was stored in an open-matrix drawer on a non-critical care floor, directly adjacent to a look-alike package (midazolam/Versed). There were no physical or digital barriers.	The pharmacy technician who stocked the ADC placed the two drugs in adjacent pockets. The pharmacist who approved the ADC layout failed to recognize and mitigate this catastrophic risk.
2. Manufacturer Packaging	The manufacturer used similar size, shape, and label coloring for both vecuronium and midazolam vials, creating a powerful visual trap.	(N/A – This is a design-level failure)
3. Nurse Medication Retrieval	Lack of a policy requiring barcode scanning at the ADC upon removal. High-stress, high-workload environment.	The nurse, seeing the familiar packaging and location, succumbed to confirmation bias and did not adequately read the vial label before administering the drug.
4. Bedside Administration	Hospital policy did not require an independent double-check for IV sedatives on this unit.	The nurse administered the medication without a second check, which could have caught the error at the final step.

Prevention Protocols Implemented After the Event

This sentinel event prompted a complete overhaul of high-alert drug management:

• Storage & Segregation Mandate:
  • All neuromuscular blockers were immediately removed from ADCs in all non-critical care areas (like med-surg floors).
  • In critical care areas (ICU, ED, OR), all paralytics were moved to lidded, segregated compartments within the ADC, brightly labeled with “WARNING: PARALYZING AGENT.“
• Pharmacy Labeling:
  • Pharmacy began applying a fluorescent orange auxiliary label reading “WARNING: PARALYZING AGENT – CAUSES RESPIRATORY ARREST” to every individual vial before it was sent to the unit.
• Technology Upgrades:
  • A hard-stop alert was built into the ADC. Now, before the lid of a paralytic pocket can open, the user must read a warning and type “YES” to acknowledge that the patient is ventilated.