Safety device evaluations produce efficacy data
CDC assesses phlebotomy and suture needles
Recent evaluations of safer needle devices by the federal Centers for Disease Control and Prevention showed that phlebotomy devices with safety features and blunt suture needles can help prevent percutaneous injuries to health care workers with no significant patient care complications.1,2
To assess the performance of needle safety devices for phlebotomy, the CDC conducted a two-phase study at six university-affiliated urban hospitals. (See cover story in this issue.) Each hospital selected the products they would evaluate from among a bluntable vacuum-tube blood collection needle activated while in the patient’s vein (Punctur-Guard from Bio-Plexus in Tolland, CT), a vacuum-tube blood collection needle with a hinged recapping sheath (Venipuncture Needle-Pro from Smith Industries [Concord Portex] in Keene, NH), and a resheathable winged steel needle (Safety-Lok from Becton Dickinson in Franklin Lakes, NJ). Each product requires HCWs to activate the safety feature during or after phlebotomy. Workers received comprehensive hands-on training with the equipment.
Survey estimated underreporting
The assessment compared safety devices with conventional phlebotomy devices, not with each other. In phase I of the study, which lasted between nine and 12 months, HCWs used conventional phlebotomy devices, and investigators conducted enhanced injury surveillance. Four groups of workers who routinely performed phlebotomies completed an anonymous survey to estimate needlestick underreporting rates and determine the average number of phlebotomies performed each day and the average number of days worked each week. Injury rates in each group were estimated by dividing the number of reported phlebotomy-related injuries during the study period (adjusted for underreporting by occupation) by the total number of phlebotomies performed.
During phase II, which ranged from six to 15 months, conventional phlebotomy devices were replaced with safety devices hospitalwide, and enhanced injury surveillance continued. Investigators inventoried the autoclaved contents of a representative sample of disposal containers to determine rates of safety device usage and safety feature activation. The HCW survey was repeated, and the estimated needlestick injury rates for safety and conventional devices were compared. The second survey also determined worker satisfaction with safety devices and the occurrence of adverse effects on patients during phlebotomy procedures.
The overall response rate for each of the two surveys was about 75%; 1,699 HCWs responded in phase I and 1,421 in phase II. Survey data included the following:
• Overall, respondents acknowledged reporting 302 (54%) of 563 needlestick injuries sustained from all types of needles the previous year.
• Percutaneous injury reporting rates varied by occupation:
Phlebotomists reported 91% of their injuries.
Nurses reported 68% of their injuries.
Medical students reported 35% of their injuries.
Residents reported 31% of their injuries.
• Within occupations, reporting rates were similar among hospitals and between the two surveys.
Percutaneous injury rates for safety devices were lower than those for conventional devices. (See chart, p. 42.) Data related to the 41 injuries associated with safety devices include the following:
• 34 (83%) involved winged steel needles.
• Seven (17%) involved vacuum-tube blood-collection needles.
• 25 (61%) involved an injury before safety feature activation was appropriate or possible.
• Six (15%) occurred during safety feature activation (all with Safety-Lok).
• For eight (20%), the safety feature had not been activated.
• For two (5%), the injury cause was unknown.
In response to the phase II survey question, "Do you prefer the safety device over conventional equipment?" of 1,879 responses related to one or more of the three devices, 822 (44%) responded yes, 622 (33%) said no, and 435 (23%) were unsure.
Regarding patient care effects, the CDC report states, "Although the assessment of potential patient complications in this study was limited, short-term complications were clinically minimal, and although patients were not systematically monitored for long-term follow-up, phlebotomy needles are not in-dwelling devices and long-term complications of phlebotomy are rare."
The phlebotomy device report suggests that "safety devices for phlebotomy can reduce the risk for occupational [percutaneous injuries] among HCWs," the report continues. "In particular, there was a significant reduction in phlebotomy-related [injuries] associated with use of each of the vacuum-tube blood-collection devices and a reduction in [injuries] associated with use of the winged steel needles."
Further reductions might result from increased use of safety devices or increased safety feature activation, the CDC says.
Results also suggest that safety devices for phlebotomy "may be generally acceptable to users," the study notes. Safety feature activation rates and user acceptability could depend on factors such as the HCW’s perceived risk for occupational infection, device design, training before and after device introduction, time needed to become adept at device use, ease of use, necessary technique changes, and previous experience with safety devices.
The second CDC study notes that percutaneous injuries have been reported during up to 15% of surgical procedures, mostly associated with suturing. However, another report points out that injuries during surgery are far less likely to be reported than injuries incurred elsewhere in a hospital.3 One study showed that as few as 4% of blood exposures observed in the operating room were reported to a hospital’s employee health department.4
Most suturing utilizes conventional curved suture needles, but blunt suture needles (curved suture needles with a relatively blunt tip) might be less likely to cause injuries because "they do not easily penetrate skin," the CDC says. Blunt suture needles can replace conventional curved needles for suturing many tissues, although they might require more pressure to penetrate.
From March 1993 through June 1994, the CDC collaborated with three New York City teaching hospitals to evaluate a blunt suture needle (Ethiguard from Ethicon in Somerville, NJ) in gynecologic surgery, excluding laparoscopy and dilation and curettage procedures. Trained nurse observers recorded information about the nature and frequency of percutaneous injuries and the number and type of suture needles used. Injuries observed or reported were confirmed by inspection of HCWs’ hands before they left the operating room.
Beginning in February 1994, conventional suture needles were replaced by blunt needles on surgical instrument trays, but surgeons could request conventional needles. During the study period, 1,464 procedures were observed; 1,062 (73%) of these were performed using only conventional curved needles, 55 (4%) using only blunt needles, and 347 (24%) using both. Straight suture needles were used in 104 procedures.
Overall, 87 percutaneous injuries occurred during 84 (6%) of the 1,464 procedures. Of those injuries, 61 (70%) involved suture needles. Suture needle injuries fell into the following categories:
• 56 (92%) were associated with conventional curved needles.
• five (8%) were associated with straight eedles.
• no injuries were associated with blunt needles.
26 injuries (30%) involved other surgical devices.
Percutaneous injury rates associated with use of curved suture needles were 1.9 per 1,000 conventional needles used and zero per 1,000 blunt needles used. (See chart at left for injury rates.)
In 25 (6%) of the 402 procedures in which blunt needles were used, surgeons reported technical difficulties with blunt needles, such as problems penetrating tissue (18), tearing of tissue (three), needle slippage (three), and bleeding when the needle entered the tissue (one). However, the CDC points out that "none of these were reported to be clinically important." Blood loss and operative times were similar in procedures performed with or without blunt needles. Long-term complications were not assessed.
"The findings indicate that use of blunt needles was associated with statistically significant reductions in [percutaneous injury] rates, minimal clinically apparent adverse effects on patient care, and general acceptance by gynecologic surgeons in these hospitals," the study states.
The Public Health Service will continue to evaluate the findings from both studies "to assess the need for further guidance on selection, implementation, and evaluation of safety devices in health-care settings," the report concludes.
References
1. Centers for Disease Control and Prevention. Evaluation of safety devices for preventing percutaneous injuries among health-care workers during phlebotomy procedures Minneapolis-St. Paul, New York City, and San Francisco, 1993-1995. MMWR 1997; 46:21-25.
2. Centers for Disease Control and Prevention. Evaluation of blunt suture needles in preventing percutaneous injuries to health-care workers during gynecologic surgery procedures New York City, 1993-1994. MMWR 1997; 46:25-29.
3. Jagger J, Balon M. EPINet Report: Suture needle and scalpel blade injuries: Frequent but underreported. Adv Exp Prev 1995; 1:1, 6-8.
4. Lynch P, White MC. Perioperative blood contact and exposures: A comparison of incident reports and focused studies. Am J Infect Control 1993; 21:357-363.
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