Study of Blood Contact in Simulated Surgical Needlestick ... - CCIH

infection control and hospital epidemiology january 2009, vol. 30, no. 1
original article
Study of Blood Contact in Simulated Surgical Needlestick Injuries
With Single or Double Latex Gloving
Andreas Wittmann, PhD; Nenad Kralj, MD, MScD; Jan Köver, BA; Klaus Gasthaus, Dipl Phys;
Friedrich Hofmann PhD, MD, MScD
objective. Needlestick injuries are the most common injuries that occur among operation room personnel in the health care service.
The risk of infection after a needlestick injury during surgery greatly depends on the quantity of pathogenic germs transferred at the point
of injury. The aim of this study was to measure the quantity of blood transferred at the point of a percutaneous injury by using radioactively
labeled blood.
design. This study was conducted to evaluate the risk of infection through blood contact by simulating surgical needlestick injuries ex
vivo. The tests were conducted by puncturing single and double latex gloves with diverse sharp devices and objects that were contaminated
with Technetium solution–labeled blood.
results. A mean volume of 0.064 mL of blood was transferred in punctures with the an automatic lancet at a depth of 2.4 mm through
1 layer of latex. When the double-gloving indicator technique was used, a mean volume of only 0.011 mL of blood was transferred (median,
0.007 mL); thus, by wearing 2 pairs of gloves, the transferred volume of blood was reduced by a factor of 5.8.
conclusions. The results revealed that double gloving leads to a significant reduction in the quantity of blood transferred during
needlestick injury.
Infect Control Hosp Epidemiol 2009; 30:53-56
In a recent large survey, approximately 99% of all surgeons
said that they had experienced a needlestick injury over the
course of their professional lives. Among those surveyed, the
mean number of needlestick injuries over the previous 5 years
was 8; however, only approximately one-half of the surgeons
reported their injuries. 1 Surgical glove punctures often go
unnoticed during surgery; in other words, undetected blood
contact and/or needlestick injuries can occur. 2
The risk of infection after a needlestick injury that occurs
during surgery greatly depends on the quantity of pathogenic
germs transferred at the point of injury (resulting from the
quantitative blood contact) and on the probability that the
instrument was used for an infectious patient. The aim of
this study was to measure the quantity of blood transferred
at the point of a percutaneous injury by using radioactively
labeled blood. Surgical blades and automatic lancets were
used in this study. Because the literature regularly cites the
supposed protective effect of double gloving, the blood contact
volumes for needlestick injuries through a double layer
of latex were also determined, to assess the protective efficacy
of double gloving.
methods
We chose an ex vivo model for conducting the tests. Circular
samples of fresh pork skin (thickness, approximately 19 mm)
were made with use of a stamping tube. Then, 2-mL samples
of fresh, human whole blood were obtained by using the
Sarstedt Monovette system, and sodium citrate was added to
the samples to prevent coagulation during the subsequent
tests. The blood sample for each test was obtained from the
same person performing the test to rule out any risk of
infection.
First, 1.5 mL of blood was pipetted from the available
sample and was mixed with approximately 1 mL of highly
radioactive (approximately 15 MBq/mL) Technetium solution
( 99 Tc). The activity in the 1.5-mL radioactive blood sample
was gauged by using an activimeter (Isomed 2000) and was
recorded.
To simulate the percutaneous injuries, the samples were
mounted in a holder, and a single finger from a medical glove
(Biogel; Mölnlycke) was stretched over the sample. The patented
double-gloving technique with indicator (BiogelEclipse
Indicator; Mölnlycke) was used to test blood contact with
From the Department of Safety Engineering, University of Wuppertal (A.W., N.K., J.K., F.H.), and the Helios Klinikum Wuppertal, Klinik für Nuklearmedizin
(K.G.), Wuppertal, Germany.
Received July 3, 2008; accepted August 3, 2008; electronically published December 2, 2008.
� 2008 by The Society for Healthcare Epidemiology of America. All rights reserved. 0899-823X/2009/3001-0010$15.00. DOI: 10.1086/593124

54 infection control and hospital epidemiology january 2009, vol. 30, no. 1
double-gloved hands. This double-gloving technique involves
use of a green inner glove that is an approximately half-size
larger than necessary and that is worn with a straw-colored
outer glove.
We only conducted tests with at least 1 layer of latex, because
it is no longer common to perform operations without
sterile gloves. Each test configuration was repeated 40 times
under identical conditions.
To simulate punctures with surgical suturing needles, we
first applied 3 mL of blood with a dosing pipette (Brand
Transferpette 20 mL; accuracy, 0.02%) to the outside of each
test glove. Then, preloaded safety lancets (Owen Mumford
Unistik3 Normal, 21G; depth of puncture, 2.4 mm ) were
used to pierce the glove through the applied blood. By using
preloaded safety lancets, we were able to ensure that each
puncture took place under identical conditions (ie, the same
duration and depth of puncture). Injuries caused by sharp
objects such as bone fragments and scissor tips were also
simulated with an automatic lancet (Owen Mumford Unistik2
Neonatal, 18G; depth of puncture, 1.8 mm) equipped with
a blade-shaped needle (Figure 1). These tests were also conducted
by puncturing a glove with 3 mL of preapplied blood.
Punctures with scalpel blades (Otto Rüttgers KG Mini
Blades [used for microsurgery]; material thickness, 0.6 mm)
were made by using a specially constructed automated puncturing
device (Figure 2). The scalpel blades were immersed
in blood at a depth of 10 mm for 30 seconds; then, the
puncturing device performed identical punctures (depth, 3
mm). We originally developed the puncturing device for measuring
blood volume transfers with cannule punctures. The
device reproducibly and constantly maintains the testing parameters,
such as puncture depth, duration, and speed.
Each sample was then gauged by using a g well-counter
connected to a computer (Maestro MCB 129). The transferred
blood volume was calculated according to the radioactive
decay determined 1 minute after blood contamination.
figure 1. The 2 automated lancets used in the study: Unistik
Normal (left) and Unistik Neonatal (right).
figure 2. Automated puncturing device with which scalpel
blade injuries were simulated.
Before taking measurements, the gauge was calibrated daily
to the energy region of the Technetium activity with use of
2 different emitters ( 131 I and 99 Tc). The region of interest was
calibrated to 10 MeV greater than and 10 MeV less than the
mean b-decay energy (141 MeV) of the 99 Tc isotope. The data
were analyzed using SPSS, version 14 (SPSS).
results
A mean volume of 0.064 mL of blood (median, 0.037 mL;
standard error of the mean [SEM], 0.012 mL) was transferred
in punctures with the Unistik3 Normal automatic lancet at
a depth of 2.4 mm through 1 layer of latex. With the doublegloving
indicator technique, a mean volume of only 0.011
mL of blood (median, 0.007 mL; SEM, 0.003 mL; P ! .05)
was
transferred; thus, use of 2 pairs of gloves, the transferred
volume of blood was reduced by a factor of 5.8.
Punctures with the blade-shaped Unistik2 Neonatal lancet
through a single layer of latex transferred a mean volume
(�SD) of 0.133 � 0.069 mL of blood (median, 0.113 mL;
SEM, 0.011 mL), which was considerably more than the
amount transferred when punctures were made with the needle-shaped
Unistik3 Normal lancet, even though the puncture
depth of the Unistik2 Neonatal lancet was only 1.8 mm. When
punctures were made through a double layer of latex, the
transferred mean volume (�SD) decreased to 0.035 �
0.033 mL (median, 0.027 mL; SEM, 0.005 mL; P ! .05),
which
resulted in a factor of protection of 3.8.
Needlestick injuries through a single layer of latex simulated
with blood-contaminated mini-blades resulted in a
mean transferred volume of blood (�SD) of 0.168 � 0.102
mL (median, 0.141 mL; SEM, 0.016 mL); through a double
layer of latex, the mean transferred volume of blood (�SD)
was 0.036 � 0.031 mL (median, 0.028 mL; SEM, 0.005 mL;
P ! .05).
Double gloving resulted in a factor of protection of
4.6 (Figure 3).
All punctures of the double layer of latex were clearly identifiable
by the green coloring of the puncture site. This col-

figure 3. Box plot showing the transferred blood volume in ex
vivo tests with 3 different automated puncture devices and with
single and double gloving. Grey boxes, interquartile range (IQR);
black lines within the boxes, median values; horizontal lines outside
boxes, range excluding outliers and extreme values; black circles, outliers
(values 11.5 and !3 times the IQR from the 75th percentile);
stars, extreme values (values 13 times the IQR from either the 25th
or the 75th percentiles).
oring is the result of fluids entering the space between the
gloves through the puncture site, which causes the green inner
glove to show through the straw-colored outer glove.
discussion
A series of studies has been conducted worldwide on the risk
of surgical personnel being exposed to blood-borne pathogens.
3 In those studies, blood contact and/or injury was usually
detected by inspecting the latex gloves worn during surgical
procedures. The glove puncture rate was most frequently
determined by filling the gloves with water or by using electrical
measuring methods similar to those used for condom
testing. 4 In every study, the glove puncture rate depended on
the type of surgical procedure (ie, there is an increased the
risk of blood contact during longer procedures 5 ); operations
that required great effort and involved bones6,7or deep locations
8 resulted in glove puncture rates of up to 70%. The
risk of blood contact during endoscopic procedures was significantly
lower, with a puncture rate of approximately 9%. 9–
11
The lead surgeon and the assisting personnel have the highest
risk of injury. 12,13
Improved protection against infection can be achieved by
wearing 2 pairs of gloves. Many studies have proven the ben-
surgical needlestick injuries 55
efits of double gloving in preventing blood contact. Studies
from the United States 14,15 determined that double gloving
can reduce the risk of blood contact by a factor of 10. Two
other studies found that use of doubled surgical gloves reduced
the rate of blood contamination among surgeons from
70% (in both studies) to 13% (in one study) and 2% (in the
other study). 16,17 The rate of blood contamination was minimized
despite a puncture in the outer glove, because the
inner glove remained intact in up to 82% of cases. 18–20
Protection against infection can be increased even more
by double gloving with an indicator glove. This gloving technique
includes a colored inner glove and an outer glove that
is neutral in color. If the outer glove is punctured during the
operation, the fluids present in all procedures will appear as
a clearly visible spot at the site of the puncture. Once such
a spot is noticed by any member of the surgical team, the
glove can be replaced, thus minimizing the risk of an infection
that results from continuing with the operation.
To date, the studies conducted on early detection of glove
punctures during surgical procedures have revealed that indicator
gloves are very effective. Compared with complicated
electronic indicator systems that often tend to sound the
alarm because of changes in the conductivity of the latex
gloves, 21,22 indicator gloves enable the detection of up to 100%
of punctures immediately after they occur. 23,24
A meta-analysis of the 18 studies conducted on glove safety
worldwide found that double gloving led to 3 times fewer
contacts with blood, compared with using a single pair of
gloves. No concentrations of punctures on the outer glove
were found that could indicate a reduction in hand sensitivity
or dexterity. 3
Although the protective effect of double gloving is very
evident, it is not yet routine practice. This is mainly attributable
to the alleged reduction in dexterity and sense of touch
through the double layer of latex. A study conducted at the
University of Wuppertal (Wuppertal, Germany), in which
participants underwent a standard neurological 2-point discrimination
test and a “dice test” (in which the blindfolded
participant had to determine the number of pips on dice of
various sizes), found no significant reductions in the sense
of touch in those wearing 2 pairs of gloves. 25 A US study that
tested both sense of touch and dexterity found that 2 pairs
of gloves had an adverse effect only on the surgeons who
normally operated with a single pair of gloves; within a short
period, however, even these surgeons became accustomed to
using 2 pairs of gloves. 26
Our tests prove that double gloving also has a positive effect
on the blood volumes transferred by surgical needlestick injuries.
Use of 2 pairs of gloves led to a significant reduction
in transferred blood volume in all of the tests.
Therefore, it has been established that double gloving provides
a significant reduction in the risk of blood exposure to
surgical personnel. Indicator systems have the added advantage
of preventing the infection of unnoticed injuries, which

56 infection control and hospital epidemiology january 2009, vol. 30, no. 1
can occur with glove punctures that are difficult to detect.
The aforementioned double-gloving techniques already exist,
and their benefits, compared with single gloving, are known
in the field of surgery. In conclusion, double gloving should
be recommended for all surgical procedures and should be
required for procedures for patients with known infections
or for patients who have not yet been tested for infections.
acknowledgments
Financial support. Regent Medical Overseas, Mölnlycke Healthcare.
Potential conflicts of interest. All authors report no conflicts of interest
relevant to this article.
Address reprint requests to Andreas Wittmann, PhD, University of Wuppertal,
Dept. of Safety Engineering, Gauss Str. 20, D-42097 Wuppertal, Germany
(andwitt@uni-wuppertal.de).
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