Radiation Exposure of Anesthesiologists - Journal of Clinical Anesthesia

Radiation Exposure of Anesthesiologists K&tine H. Henderson, MD,* Jeffrey K. Lu, MD,* Keith J. Strauss,MS,-/- S.T. Treves, MD,1 Mark A. Rockoff, MD$j Departments of Anesthesia and Radiology, Children’s Hospital Medical Center, and Department of Anaesthesia, Harvard Medical School, Boston, MA.

Study Objective: To determine the level o/“radiation exposure of anesthesiologists in the operating rooms and cardiac cathetevization laboratory. Design: Prospective study of all anesthesia fellows. Setting: Operating rooms (ORs) and radiolog3!department of a tertiary care pediatric hospital. Subjects: Anesthesiologists caringforpatients in a pediatric hospital requiting anesthesia or monitored anesthesia care. (Patients weve not directly studied.) Measurements and Main Results: Anesthesiologists wore standard radiation safety film badges, which were sensitive to cumulative doses of radiation greater than 10 mrem. In the ORs, anesthesiologists were exposed to less than 10 mrem/mon. In the cardiac catheterization laboratory, they had dosimettic readings that rangedfrom 20 to 180 mrem/ mon and frequently exceeded the guidelines fm nonradiation workers. Conclusions: There is no need for ,routine dosimettic monitoring of anesthesiologists working in the OR setting, since this is associated with negligible radiation exposure. Monitoring of radiation film badges should be considered for anesthesiologists who frequently work in fluoroscopy areas, such as the cardiac catheterization laboratory. All personnel working near radiation sources should wear appoptiate shielding and, wheneuer patient safety permits, distance themselves as far as possible from the source of radiation.

Keywords:Cardiac catheterization;

fluoroscopy;

radiation

safety; radiography.

*Fellow in Anesthesia tDirector neering

of Radiological

IProfessor

of Radiology

Physics and Engi-

SAssociate Professor of Anaesthesia rics)

(Pediat-

Address reprint requests to Dr. Rockoff at the Department of Anesthesia, Children’s Hospital Medical Center, 300 Longwood Avenue, Boston, MA 02115, USA. Presented in part at the Annual Meeting of the American Societv of Anesthesiologists, San Francisco, October 27-30, 1991. Received for publication

June 25, 1992; re-

vised manuscript accepted for publication September 10, 1993. 0 1994 Butterwortb-Heinemann 1. Clin. Anesth. 6~37-41. 1994.

Introduction Because of advances in diagnostic and interventional radiology, anesthesiologists are increasingly participating in the care of patients undergoing fluoroscopy, angiography, and conventional roentgenography. This is especially true for anesthesiologists who work with children, since sedation or general anesthesia is often required to perform these studies. Concern has been raised about the level of radiation to which radiologists, cardiologists, and surgeons performing these procedures are exposed.‘-5 It has been our observation that for many procedures, the operator is able to step away from the field or leave the room during the period of radiation exposure. However, patient care frequently mandates that the anesthesiologist remain at the bedside, particularly during invasive procedures with monitored sedation, such as cardiac catheterization, when it may be dangerous for the patient to make any sudden movement. Little information is available concerning the radiation exposure of anesthesia personnel, either in the operating room (OR) or in the radiology suite. This study was performed to determine the degree of occupational radiation to which anesthesiologists are exposed and to identify factors that correlate with excessive risk. .J. (Xn. Anesth., vol. 6, January/February

1994

37

Ongina

Contributions

Materials and Methods

Results

The radiation exposure of 16 anesthesia fellows working at Children’s Hospital in Boston during a 2-month period was measured. Each physician wore a standard radiation safety film badge (Tech-Ops, Landauer, Glenwood, IL) clipped to his or her surgical cap at the forehead. This permitted uniform measurements in a location that has previously been shown to approximate radiation exposure to the lens.4 These film badges are capable of monitoring beta, gamma, radiograph, and fast neutron exposure. They are sensitive to cumulative doses of radiation greater than 10 mrem, and measurements are reliable within 10% of the reported dose. Film badges were kept in a common location between workdays to prevent nonoccupational exposure. Badge exposure was analyzed monthly. Eleven or twelve of the physicians were assigned to the general ORs, and four or five were assigned to a cardiac anesthesia team providing care only in the cardiac ORs and the cardiac catheterization laboratory (CCL). Fellows assigned to the Pain Treatment Service or intensive care unit were excluded from the study. Noted daily were the types of procedures performed, number of hours spent participating in direct patient care, location of procedures in the hospital (e.g., OR, angiography suite, CCL), and type of shielding and/or protective measures used. Data sheets were collected daily from each fellow and checked by one of the investigators for completeness and accuracy. In addition, the results of dosimetric readings from the first month of the study were shared with the participants as soon as they were available (1 week into the second month of the study) to enable them to minimize their radiation exposure subsequently. Fellows changed service every month, with some individuals participating in the study for only 1 of the 2 months, so data for each fellow each month were considered separately.

During the study period, both the OR and cardiac groups spent a comparable amount of time involved in direct patient care, averaging 99 hours per month (Tables 1 and 2). Anesthesiologists in the OR group were exposed to 4.2 2 1 radiographs per month (mean f SD). These were primarily portable chest and extremity radiographs. Each anesthesiologist in the OR was exposed to less than 5 minutes of cumulative fluoroscopy time per month. This time was mainly for orthopedic procedures and placement of indwelling central venous catheters, and occasionally for an angiogram in the radiology department. Overall, during their ORrotation, 5 of20 anesthesiologists left the OR (stepped behind a door) during the period of radiation exposure. An additional 2 individuals stayed in the room but distanced themselves more than 10 feet from the radiograph machine during each radiologic procedure. Every anesthesiologist who remained near the patient during the time of exposure wore a protective apron, but few wore a thyroid shield. Despite this intraoperative proximity to roentgenography and fluoroscopy, the dosimetric reading for every anesthesiologist in the OR group was undetectable (less than 10 mrem/mon). Anesthesiologists in the cardiac group spent 21 ? 10 hours per month in the CCL. A typical 6 to 8-hour shift in the CCL included two to three cardiac catheterizations, with or without interventional procedures. The amount of fluoroscopy time averaged 30 minutes, with a range of 14 to 85 minutes. Therefore, cardiac anesthesiologists were exposed to an average of 225 minutes of fluoroscopy per month. Every member of the cardiac group wore an appropriate protective apron during each CCL procedure. Thyroid shielding was worn in only 5% of cases. The anesthesiologist left the room during fluoroscopy in 5%

Table 1.

Fellow

Summary

of Data from Study Month

Service

1 2 3 4

OR OR OR OR

5 6 7 8 9 10 11 12 13

OR OR OR OR OR

Cardiac Cardiac Cardiac Cardiac

clinical Hours per Month

l*

Radiographs per Month

Fluoroscopies

CCL

per Month

Hours per Month

1

0

2 3 4 3 2 4

3

0 0 0 0 0 0 0 0 0

95 133 85 125 130 58 113 76 86 133 88 133 89

1

2 0 0 0 0

*The film badges of two OR fellows were lost before dosimetric Treatment Service was excluded from the study. CCL = cardiac catheterization

38

laboratory;

OR = operating

J. Clin. Anesth., vol. 6, January/February

1994

room.

1 2 1 1

2 1 1

6 8 4 9 readings could be obtained,

32 26 12 24

Dosimetry (mrem/mon)