Nurse exposure to waste anesthetic gases in a post anesthesia care unit

60 Pages·2015·2.22 MB·English

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USF Tampa Graduate Theses and Dissertations USF Graduate Theses and Dissertations
2006
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Larry A. Flack
University of South Florida
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Nurse Exposure to Waste Anesthetic Gases in a

Post Anesthesia Care Unit

by

Larry A. Flack II

A thesis submitted in partial fulfillment
of the requirements for the degree of
Master of Science in Public Health
Department of Environmental and Occupational Health
College of Public Health
University of South Florida

Major Professor: Steven Mlynarek, Ph.D.
Yehia Hammad, Sc.D.
Eugene Szonntagh, Ph.D.

Date of Approval:
March 24, 2006

Keywords: Nitrous Oxide, Isoflurane, Desflurane, Sevoflurane,
Occupational Air Sampling

©Copyright 2006, Larry A. Flack II
Acknowledgements

A special thanks to Dr. Steven Mlynarek for his expertise,
encouragement, and support for this study. I would like to thank Drs.
Hammad, Szonntagh, Bernard, Rentos and Roets for their support and
guidance throughout my academic career at the College of Public
Health.
I would also like to thank my parents for allowing me the
opportunity to pursue this graduate degree. Your love and support
through the years has been an inspiration. I am very fortunate and
grateful to have you both as parents.
Table of Contents

List of Tables ii

List of Abbreviations and Acronyms iii

Abstract iv

Introduction 1

Literature Review 4
NIOSH Recommended Exposure Limits 4
Controversy Surrounding the Development of NIOSH RELs 9
PACU Nurses Breathing Zone during Patient Care 11
Anesthetic Agents 12
Nitrous Oxide 12
Halogenated Anesthetic Gases 14
Studies of PACU Nurse Exposures to Waste Anesthetic Gases 16
Controlling Waste Anesthetic Gas Concentrations in a PACU 17
Purpose and Hypotheses of this Study 19

Methods 20
Participants 20
Sampling Protocol 20

Results 23
Nitrous Oxide 23
Halogenated Anesthetics (Isoflurane, Sevoflurane, and
Desflurane) 24
Nitrous Oxide in Combination with Halogenated Anesthetics 30
Comparison of Active and Passive Sampling Methods 32

Discussion 33
Nurse Exposures to Waste Anesthetic Gases 33
Comparison of Active and Passive Sampling Methods 36
PACU Ventilation 39

Conclusions 41

References 43

Appendices 46
Appendix A: Laboratory Analytical Report 47
i
List of Tables

Table 1. Chemical and Physical Descriptions of Anesthetic Agents
(Merck, 2001). 15

Table 2-A. PACU Nurse Exposure Levels to Nitrous Oxide. 23

Table 2-B. Summary of Nurse Exposures to Nitrous Oxide. 24

Table 3-A. PACU Nurse Exposure Levels to Isoflurane (Passive
Sampling). 25

Table 3-B. PACU Nurse Exposure Levels to Isoflurane (Active
Sampling). 25

Table 4-A. PACU Nurse Exposure Levels to Sevoflurane (Passive
Sampling). 26

Table 4-B. PACU Nurse Exposure Levels to Sevoflurane (Active
Sampling). 27

Table 4-C. Summary of Nurse Exposures to Sevoflurane. 27

Table 5-A. PACU Nurse Exposure Levels to Desflurane (Passive
Sampling). 28

Table 5-B. PACU Nurse Exposure Levels to Desflurane (Active
Sampling). 29

Table 5-C. Summary of Nurse Exposures to Desflurane. 29

Table 6. PACU Nurse Exposure Levels to Nitrous Oxide used in
Combination with a Halogenated Anesthetic. 31

Table 7. Comparison of Active and Passive Sampling Methods for
Halogenated Anesthetic Gases. 32

Table 8. Summary of Waste Anesthetic Gas Exposure Data. 35

Table 9. Summary of Occupational Exposure Limits for Waste
Anesthetic Gases (ACGIH, 2005 and NIOSH, 1977). 36

ii
List of Abbreviations and Acronyms

ACGIH American Conference of Governmental Industrial
Hygienists

AIHA American Industrial Hygiene Association

ANOVA Analysis of Variance

CI Confidence Interval

ICU Intensive Care Unit

MAC Minimum Alveolar Concentration

NIOSH National Institute of Occupational Safety and Health

OSHA Occupational Safety and Health Administration

PACU Post Anesthesia Care Unit

PPM Parts Per Million

REL Recommended Exposure Limit

TWA Time-Weighted Average

iii
Nurse Exposure to Waste Anesthetic Gases in a
Post Anesthesia Care Unit

Larry A. Flack II

ABSTRACT

It has been estimated that over 200,000 healthcare
professionals may be exposed to waste anesthetic gases and are at
risk of occupational injury. In 1977, the National Institute for
Occupational Safety and Health (NIOSH) issued the publication:
Criteria for a Recommended Standard….Occupational Exposure to
Waste Anesthetic Gases and Vapors. This publication was based
primarily on scientific evidence from human and animal studies
suggesting that chronic exposures to anesthetic gases increases the
risk of both spontaneous abortion and congenital abnormalities in
offspring among female workers and wives of male workers exposed to
waste anesthetic gases. In this recommended standard, NIOSH
defines the recommended exposure limits (REL) for nitrous oxide and
halogenated anesthetics. NIOSH recommended a time-weighted
average (TWA) REL of 25 parts per million (ppm) for nitrous oxide over
the period of administration. The REL for halogenated anesthetic
gases is a ceiling limit of two ppm.
In this study, waste anesthetic gas exposures to seven Post
Anesthesia Care Unit (PACU) nurses were quantified during one day of
air sampling within their breathing zones.
Nitrous Oxide was sampled using a ChemExpressTM Personal
Monitor (Assay Technology, Inc. Pleasanton, CA) attached to the nurse’s
lapel for approximately three hours. A total of 15 samples were
collected. Isoflurane, desflurane, and sevoflurane were sampled using a
ChemExpressTM Personal Monitor (Assay Technology, Inc. Pleasanton,
CA) attached to the nurse’s lapel for approximately three hours. A total
of 15 samples were collected. In addition, Isoflurane, desflurane, and
sevoflurane were also sampled using Anasorb® 747 sorbent tubes (SKC,
Inc. Eighty Four, PA) to compare the passive and active sampling
methods. The tubes were attached to the nurses lapel for one hour. A
total of 15 samples were collected.
iv
The exposures to nitrous oxide and halogenated anesthetics were
below the NIOSH RELs.
An Analysis of Variance (ANOVA) showed a statistically significant
difference (p < 0.05) in the active and passive sampling methodologies.

v
Introduction

In 1977, the National Institute for Occupational Safety and
Health (NIOSH) issued the publication: Criteria for a Recommended
Standard….Occupational Exposure to Waste Anesthetic Gases and
Vapors. This publication was based primarily on scientific evidence
from human and animal studies suggesting that chronic exposures to
anesthetic gases increases the risk of both spontaneous abortion and
congenital abnormalities in offspring among female workers and wives
of male workers (NIOSH, 1977). In addition, acute exposures to
waste anesthetic gases have been associated with headaches, nausea,
fatigue, and irritability (NIOSH, 1977). The scientific evidence used to
develop the recommended standard has been questioned, particularly
regarding the validity and reproducibility of the studies. Nonetheless,
NIOSH issued recommended exposure limits (REL) for nitrous oxide
and halogenated anesthetic gases (e.g. sevoflurane, desflurane,
isoflurane, halothane). The REL for nitrous oxide is a time weighted
average (TWA) concentration of 25 parts per million (ppm) over the
period of administration (NIOSH, 1977). The REL for halogenated
anesthetic gases is a ceiling limit of two ppm (NIOSH, 1977).
1
The majority of human evidence used to develop the NIOSH
publication involved mainly hospital operating room personnel.
However, NIOSH believes that other anesthetizing areas have the
potential for exposure to waste anesthetic gases that could produce
adverse health effects in workers.
As of 2006, the Occupational Safety and Health Administration
(OSHA) does not have occupational exposure limits for specific waste
anesthetic gases. However in 1999, they issued a Waste Anesthetic
Gas Guidance Document (OSHA Fact Sheet No. 91-38) that
recommends exposure limits identical to the NIOSH REL’s. OSHA does
regulate exposures to waste anesthetic gases under Section 5(a)(1) of
the Occupational Safety and Health Act, referred to as the General
Duty Clause.
An area of particular concern over the past several years is the
Post Anesthesia Care Unit (PACU). Nurses working in a PACU have the
potential to be exposed to waste anesthetic gases at levels that exceed
the RELs. The potential for nurse exposure to these gases occurs
when patients are disconnected from scavenged anesthesia machines
in the operating rooms and transported to the PACU. While in the
PACU, the patient exhales waste anesthetic gases into the ambient air.
Nurses caring for these patients often work within two to three feet of
the patient’s breathing zone where waste anesthetic gas
2