Table 1.

Variance matrix of assembly critical tasks

Task	Performance shaping factors (SEIPS classification)	Failure	Example of task variability	Process variance	Outcome variance	Observed controls (SEIPS classification)
Inspect instruments for bioburden	SPD staff KSAs (person) Tray composition (organisation) SPD production pressure (organisation) ITS (tools/technology) Workstation (tools/technology)	Missed check	Tray contains 50+ instruments and with limited space on their work surface technician inadvertently mixes inspected and uninspected instruments, failing to inspect one or more instruments.	Undetected bioburden	Surgical site infection Tray defect (bioburden) New tray required OR delay Increased surgical duration Surgical deviation	▶ Remedial/specialty training (person) ▶ In-service training (organisation) ▶ Point-of-use observations for SPD (organisation)
	SPD staff KSAs (person) Instrument design (external) Lighting (physical environment)	Failed inspection	Technician inspects instrument but fails to identify bioburden hidden in instrument crevice.
Test instruments for functionality	SPD staff KSAs (person) Tray composition (organisation) Instrument design (external) SPD production pressure (organisation) Communication with point of use (organisation)	Missed check	OR did not inform SPD of issue with instrument, technician fails to test instrument as it has never been an issue previously.	Broken instrument in tray	Patient injury (burn, tear, retained object, and so on) Tray defect (non-functioning instrument) OR delay Increased surgical duration Surgical deviation New tray	▶ Remedial/specialty training (person) ▶ ITS prompt (tools/technology) ▶ In-service training request (organisation) ▶ Point-of-use observations for SPD (organisation)
	SPD staff KSAs (person) Communication with point of use (organisation) Instructions for use (external) Workstation (tools/technology)	Inappropriate or ineffective check	Technician provided with little to no knowledge of how instrument is used so test is conducted in cursory manner.
Ensure all of the correct instruments are in the tray	SPD staff KSAs (person) Instrument nomenclature (organisation/external) Instrument inventory (organisation) Instrument storage (physical environment/organisation) ITS design (external) Workstation (tools/technology) Point-of-use reprocessing (organisation)	Wrong instrument selected	The ITS places instrument details at the end of the instrument name (eg, haemostat forceps, 14 cm, curved, satin). Technician misses appended details and chooses incorrect size and finish for the instrument.	Wrong instrument added to tray	Tray defect (wrong instrument) OR delay Increased surgical duration Surgical deviation New tray required	▶ Remedial/specialty training (person) ▶ Assign technician to point-of-use area to assist with reprocessing (organisation) ▶ Standardised nomenclature (organisation) ▶ Tray auditing (organisation) ▶ Tray standardisation (organisation) ▶ OR staff training in SPD
	ITS database (organisation/external)	No image, incorrect image or poor quality image in ITS	Image missing in the ITS database so the technician performs an online search and chooses the instrument based on the search results.
	ITS database (organisation/external) Preference cards (organisation)	Incorrect tray specifications in ITS	The ITS database was not promptly updated according to the revised preference cards.	Tray missing instrument(s)	Tray defect (wrong instrument) OR delay
	ITS database (organisation/external) ITS design (external) SPD staff KSAs (person) SPD production pressure (organisation)	Failed to add instrument to tray	Technician counts instruments then adds them all to tray, instead of marking instruments individually in the ITS as they are added to tray, to save time.		Increased surgical duration Surgical deviation New tray required
	SPD staff KSAs (person) Instrument nomenclature (organisation/external) Instrument inventory (organisation) Instrument storage (physical environment/organisation) Point-of-use reprocessing (organisation) Layout (physical environment)	Difficulty locating instrument in assembly storage areas	Instruments not returned to correct tray during point-of-use reprocessing. Technician has to identify all trays used during the case then find and check each tray for the missing instrument.	Prolonged assembly	Reduced throughput
	ITS database (organisation/external)	No image or poor quality image in ITS	Technician asks supervisor or more experienced technician to help identify the correct instrument.
Prepare tray for sterilisation	SPD staff KSAs (person) SPD production pressure (organisation) Tray container design (external)	Failure to add count sheet	Technician rushing to add high-priority tray to the steam sterilisation load and forgets to add count sheet, indicators, locks, filters or tray labels.	No count sheet in tray	OR delay Tray defect (missing count sheet)	▶ Remedial training (person) ▶ Sterilisation checklist (tools/technology) ▶ Dedicated workstation for sterilisation methods (physical environment) ▶ Double-check procedure (organisation)
		Failure to add chemical indicators to the tray		Sterilisation not verifiable	OR delay Tray defect (missing indicator, filter, locks or label) New tray required
		Failure to add locks to container
		Failure to add filters to the container		Filters missing from tray containers
		Failure to add tray labels to the container		Inability to verify tray
	SPD staff KSAs (person) Sterilisation methods (external) Tray label (organisation) Instructions for use (external) Layout (physical environment)	Tray placed on wrong sterilisation cart	New instrument(s) added to tray but sterilisation method not updated in the ITS. Technician prints label from the ITS and adds tray to sterilisation cart listed on the label.	Wrong sterilisation method	Instrument damage Inventory costs Ineffective sterilisation Surgical site infection

ITS, instrument tracking system; KSAs, knowledge, skills and abilities; OR, operating room; SEIPS, Systems Engineering Initiative for Patient Safety; SPD, sterile processing department.