Cause of Device-Related Incident
Device factors; Support system failures; User errors

Clinical Specialty or Hospital Department
Clinical/Biomedical Engineering; Ophthalmology; OR / Surgery

Device Factors
Design / labeling error; Manufacturing error

Document Type
Hazard Reports

External Factors
*Not stated

Mechanism of Injury or Death
Blindness; Mechanical (puncture, perforate, lacerate, break, cut, tear, nick, crush)

Support System Failures
Lack or failure of incoming and pre-use inspections

Tampering and/or Sabotage
*Not stated

User Errors
Accidental misconnections; Failure to perform pre-use inspection

UMDNS
Vitrectomy Units [14-386]; Cataract Extraction Units, Phacoemulsification [17-596]

Misconnection of Vitrectomy Handpieces and Vitrectomy Units



Hazard [Health Devices Feb 1995;24(2):86]

Problem

Two hospitals reported incidents in which eye injuries occurred when one of the lines from a pneumatically driven vitrectomy handpiece was misconnected to the vitrectomy unit's high-pressure actuator line. The Food and Drug Administration's (FDA) Medical Device Reports (MDR) database contains two similar reports. Also, in 1993, one manufacturer's vitrectomy handpiece was recalled because connectors on the actuator and aspiration lines were reversed during manufacturing.

With this type of misconnection, a large blast of compressed air enters the eye on activation of the handpiece. In most of the reported cases, eye damage occurred, including an iris prolapse, dislocation of an implanted lens, and retinal injury. Because vitrectomy equipment from many manufacturers and distributors share the same actuator-line design, this problem could occur with any of the vitrectomy handpieces that are pneumatically driven and that have aspiration- or irrigation-line connectors that are compatible with the unit's actuator line.

Discussion

Vitrectomy handpieces are connected to the vitrectomy unit by 1) an aspiration line and 2) an actuator line. The actuator line is used to supply an oscillating pulse of positive and negative pressure on the membrane in a chamber within the vitrectomy handpiece; this oscillation of the membrane causes the cutting blade, which is connected to the back side of the membrane, to move. Some handpieces also have an irrigation line that may be integral to the handpiece or supplied as a separate irrigation cannula that the user can slip over the handpiece.

All lines are connected using Luer connectors. In addition, a stopcock may be used to allow connection of another handpiece. Depending on the particular configuration, it will be possible to connect either the handpiece's irrigation line or its aspiration line to the vitrectomy unit's actuator line. If this misconnection occurs, oscillating air pressure will be forced into the patient's eye when the unit is operated. To help prevent misconnections, most vendors use some sort of color coding for the Luer connectors; in some instances, the tubing itself has some color identifier.

Conclusions

Every time lines are reconnected and before the device is used, the handpiece should be inspected while outside the eye to detect misconnection. However, because an anterior vitrectomy is usually performed only after a posterior capsule rupture (i.e., emergency intervention), the operating room staff may be rushed and may not take the time to check the handpiece before using it. Therefore, the only way to prevent misconnections is to design the lines on the vitrectomy handpiece so that they can be connected to the machine in only the correct manner (e.g., the manufacturer could provide an actuator-line connector that is incompatible with other connectors).

Recommendations

  1. Notify all clinical staff who use pneumatic-powered vitrectomy equipment of this hazard.
  2. Inform staff of the need to inspect every ophthalmic handpiece after connecting the lines and before inserting it into the patient's eye. Inspecting all ophthalmic handpieces just before using them in the eye should already be a standard procedure, regardless of this particular problem; however, inspection is especially important until vendors incorporate design changes in their pneumatic vitrectomy systems.
  3. To check a vitrectomy handpiece before use, the scrub nurse should first make the handpiece connections to the machine's actuator and aspiration lines (and the irrigation line when present). The handpiece should then be operated in a beaker of sterile water. Air bubbles coming from the handpiece indicate that the actuator line is connected inappropriately to either the aspiration or irrigation line.

UMDNS Terms

  • Vitrectomy Units [14-386]
  • Cataract Extraction Units, Phacoemulsification [17-596]

Cause of Device-Related Incident

Device factors: Design/labeling error; Manufacturing error

User errors: Accidental misconnection; Failure to perform pre-use inspection

Support system failure: Lack or failure of incoming and pre-use inspections

Mechanism of Injury or Death

Blindness; Mechanical


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