Patient contact recall after SARS exposure.We reinterviewed healthcare workers who had been exposed to a patient with severe acute respiratory syndrome SARS) in an intensive care unit to evaluate the effect of time on recall reliability and willingness to report contact activities and infection control precautions. Healthcare workers reliably recalled events 6 months after exposure. ********** Severe acute respiratory syndrome (SARS) quickly spread within hospitals after it was first identified in Toronto, Canada, in March 2003. Healthcare workers who cared for severely ill patients with SARS were at high risk of acquiring an infection (1). Risk factors associated with SARS transmission have been assessed by using retrospective data from medical chart reviews and healthcare worker interviews (2-4). Infection control practitioners routinely use this method to determine the degree of exposure to communicable diseases in hospitals, but its reliability and validity are unknown. To better understand the impact of time on recall reliability and healthcare workers' willingness to report infection control breaches, we reinterviewed a cohort of healthcare workers who had been exposed to a patient with SARS and who had previously been studied (3). The Study During the first Toronto SARS outbreak in March 2003, 69 healthcare workers at risk for SARS were interviewed a median of 1.2 months (range 1 to 1.5 months) after exposure (3). Five months (range 4.8 to 5.3 months) after participating in this initial study, 30 of these healthcare workers were asked to participate in another study. These workers were eligible for participation in this second investigation because they had entered the index patient's room from 24 hours before intubation endotracheal intubation insertion of a tube into the trachea for purposes of anesthesia, airway maintenance, aspiration of secretions, lung ventilation, or prevention of entrance of foreign material into the airway; the tube goes through the nose (nasotracheal i.) or mouth (orotracheal i.) . nasal intubation insertion of a tube into the respiratory or gastrointestinal tract through the nose. to 4 hours after intubation. Both investigations
involved telephone or face-to-face interviews to determine the amount of
time the worker had spent in contact with the patient, the activities
that had occurred while the worker was in the patient's room, and
the personal protective equipment used by the worker. The second
questionnaire was more detailed than the first but contained a
substantial number of questions that were identical to those in the
first questionnaire.Responses to identical questions in the initial and follow-up interviews were compared and expressed as proportions. Responses obtained during the initial interview were considered the reference standard for comparison with follow-up interview responses. Agreement between the initial and follow-up responses was quantified by using the kappa Kappa Used in regression analysis, Kappa represents the ratio of the dollar price change in the price of an option to a 1% change in the expected price volatility.Notes: Remember, the price of the option increases simultaneously with the volatility. See also: Delta, Option, Volatility statistic and confidence intervals. The kappa statistic ([kappa])
is a commonly used measurement of agreement or repeatability in
epidemiologic studies. Kappa values from 0.20 to 0.39 indicated fair
agreement, values from 0.40 to 0.59 indicated moderate agreement, values
from 0.60 to 0.79 indicated good agreement, and values >0.80
indicated excellent agreement (5).Twenty-seven of the 30 eligible healthcare workers agreed to the second interview (Table 1). The proportion of healthcare workers who reported the same exposure in the follow-up interview as during the initial interview was >80% for most respiratory and airway management activities and >90% for procedures such as vascular catheter insertion. However, the proportion of similar responses was lower for routine patient care activities such as bedding change (67%) and nebulizer treatments (70%) (Table 2). Agreement between initial and follow-up responses was high for most respiratory and airway management activities, including suctioning after intubation ([kappa] = 0.63), manipulation of oxygen face mask or tubing ([kappa] = 0.70), manual ventilation man·u·al ventilation (m  n y - l)n. ([kappa] = 0.63), and mechanical
ventilation ([kappa] = 0.70). Agreement was fair to moderate for the
following respiratory procedures: intubation ([kappa] = 0.46),
suctioning before intubation ([kappa] = 0.34), and patient coughing
while the healthcare worker was in the room ([kappa] = 0.38). Agreement
was high for routine patient care activities, including emptying urinary
catheter collection bag or collecting urine sample ([kappa] = 0.63),
bathing the patient ([kappa] = 0.87), and performing oral care or
obtaining nasal swabs ([kappa] = 0.71). Agreement was also high for
inserting an arterial line arterial linen. ([kappa] = 0.75) and for cleaning the
patient's room ([kappa] = 0.65). An intra-arterial catheter. Healthcare workers were asked during both interviews to estimate whether they had spent >10 minutes, >30 minutes, or >4 hours in the patient's room. Twenty-two (88%) of the 25 healthcare workers that participated in both interviews provided the same estimates of exposure duration. Two healthcare workers overestimated and 1 underestimated the time spent in the patient's room. Kappa values ([kappa] = 0.52) did not vary according to the duration of exposure. Relative to their initial responses, on follow-up, healthcare workers tended to overestimate their presence in the patient's room during respiratory and airway management activities, particularly nebulization nebulization /neb·u·li·za·tion/ (neb?u-li-za´shun) 1. conversion into an aerosol or spray. 2. treatment by an aerosol. therapy. However, during the second interview, they were
less likely to report being in the room while a bi-level positive air
pressure unit was being used or while bedding was being changed. The
rates of overestimated responses versus underestimated responses for
other patient care activities were similar (Table 2). Healthcare workers
who subsequently developed cases of laboratory-confirmed SARS were not
more or less likely to remember their presence or absence during patient
care activities (data not shown).In the hospital, use of additional precautions (gown, gloves, and surgical masks for room entry) for methicillin-resistant Staphylococcus aureus was practiced by the healthcare workers (6). Compliance varied among healthcare workers, but the proportion of workers with the same response during the follow-up interview was >80% for all infection control precautions, except wearing a gown (76%, data not shown). In general, responses in the 2 interviews showed little variation in infection control precautions. Conclusions Our results indicate that healthcare workers in this study reliably recalled contact practices, patient care activities, and infection control precautions 5 months after their initial interview and 6 months after exposure to a patient with SARS. The proportion of identical follow-up responses averaged >85% for contact practices, patient care activities, and infection control precautions. Agreement between initial and follow-up responses was good to excellent for most respiratory practices and airway management activities, routine patient care activities, and other medical procedures. The lowest proportion of identical responses observed on the initial and follow-up interview was for being in the patient's room while the patient was coughing or spitting (59%), with a kappa value (0.38) indicating fair agreement. The risk of droplet and airborne spread of communicable diseases is assumed to be greater if a patient is frequently coughing. Hence, different infection control precautions have been recommended when caring for patients who are coughing (7). However, our results suggest that recollection of contact during this activity may not be reliable. Whether this poor reliability is related to the effect of time on memory or the intermittent nature of coughing is unclear. The inferences that can be drawn from this study are limited by the relatively small size of our cohort. Caring for patients with SARS can be a memorable and frightening event (8,9), and recall reliability in our study may not be generalized to other clinical situations. Furthermore, the similarities among questions during the 2 interviews may have resulted in the potential for recall bias, causing an overestimation of reliability within respondents (10). Finally, our study measured the reliability rather than the validity of healthcare worker recall for determining exposure risk. Nonetheless, our findings that healthcare workers reliably recalled exposure after several months following the event should be reassuring to investigators studying risk factors for SARS transmission in hospitals and to infection control practitioners assessing exposure to communicable diseases.
Table 1. Characteristics of healthcare workers and severe acute
respiratory syndrome (SARS) index patient contact
No. (%) of
healthcare
workers
Characteristics * (N = 27)
Demographic characteristics
Age group (y)
20-29 7 (26)
30-39 9 (33)
40-49 8 (30)
[greater than or equal to] 50 3 (11)
Sex: female 18 (67)
Occupation
Nurse 10 (37)
Respiratory therapist 8 (30)
Other ([dagger]) 9 (33)
No. with laboratory-confirmed SARS 3 (11)
Contact characteristics
Cumulative time spent in patient's room
([double dagger])
[less than or equal to] 10 min 9 (35)
11-30 min 8 (31)
31 min-4 h 6 (23)
>4h 3 (11)
Touched patient 16 (59)
Face [less than or equak to] 3 feet of patient 18 (67)
Contact with mucous membranes or respiratory secretions 7 (26)
Patient coughing or spitting while healthcare worker 11 (41)
was present
Performed or assisted with intubation 2 (7)
* Characteristics ascertained from initial interview.
([dagger]) Other occupation categories include service assistants,
residents, 1 physician, and 1 pharmacist.
([double dagger]) Based on 26 healthcare worker responses.
Table 2. Reliability of healthcare worker recalling presence
in a SARS patient's room during patient care activities *
No. (%) No. (%) same
affirmative response on
during initial follow-up
Activity interview interview
Respiratory characteristics
and airway management
Intubation 2 (7) 25 (93)
Suctioning before 2 (7) 24 (89)
intubation
Suctioning after intubation 2 (7) 25 (93)
Manipulation of oxygen 13 (48) 22 (82)
face mask/tubing
Manual ventilation 2 (7) 25 (93)
Mechanical ventilation 6 (22) 24 (89)
Patient coughing/spitting 11 (41) 16 (59)
while healthcare worker
present
Routine patient care
Changing bedding 11 (41) 18 (67)
Bathing patient 4 (15) 26 (96)
Emptying urinary catheter 4 (15) 25 (93)
collection bag or collecting
urine sample
Oral care or nasal swab 4 (15) 25 (93)
Stool sample or rectal 0 25 (93)
swab
Nebulizer treatments 0 19 (70)
Procedures
BiPAP 19 (70) 18 (67)
Electrocardiogram 3 (11) 23 (85)
Insertion of central venous 0 27 (100)
catheter
Insertion of peripheral 5 (18) 25 (93)
intravenous catheter or
arterial catheter
Insertion of nasogastric 0 26 (96)
tube
Insertion of urinary (Foley) 0 27 (100)
catheter
Chest physiotherapy 0 26 (96)
Other
Cleaning room/furniture 2 (7) 26 (96)
Cleaning medical 3 (11) 22 (82)
equipment
No. (%) of No. (%) of
responses responses
Activity overestimated underestimated
Respiratory characteristics
and airway management
Intubation 1 (4) 1 (4)
Suctioning before 2 (7) 1 (4)
intubation
Suctioning after intubation 2 (7) 0
Manipulation of oxygen 3 (11) 2 (7)
face mask/tubing
Manual ventilation 2 (7) 0
Mechanical ventilation 2 (7) 1 (4)
Patient coughing/spitting 8 (30) 0
while healthcare worker
present
Routine patient care
Changing bedding 2 (7) 7 (26)
Bathing patient 1 (4) 0
Emptying urinary catheter 0 2 (7)
collection bag or collecting
urine sample
Oral care or nasal swab 1 (4) 1 (4)
Stool sample or rectal 1 (4) 0
swab
Nebulizer treatments 6 (22) 0
Procedures
BiPAP 2 (7) 6 (22)
Electrocardiogram 3 (11) 1 (4)
Insertion of central venous 0 0
catheter
Insertion of peripheral 1 (4) 1 (4)
intravenous catheter or
arterial catheter
Insertion of nasogastric 1 (4) 0
tube
Insertion of urinary (Foley) 0 0
catheter
Chest physiotherapy 1 (4) 0
Other
Cleaning room/furniture 0 1 (4)
Cleaning medical 2 (7) 1 (4)
equipment
No. (%)
Activity missing Kappa 95% CI
Respiratory characteristics
and airway management
Intubation 0 0.46 0.00-1.00
Suctioning before 0 0.34 0.23-0.91
intubation
Suctioning after intubation 0 0.63 0.17-1.00
Manipulation of oxygen 0 0.70 0.44-0.97
face mask/tubing
Manual ventilation 0 0.63 0.17-1.00
Mechanical ventilation 0 0.70 0.38-1.00
Patient coughing/spitting 3 (11) 0.38 0.11-0.66
while healthcare worker
present
Routine patient care
Changing bedding 0 0.26 0.09-0.60
Bathing patient 0 0.87 0.61-1.00
Emptying urinary catheter 0 0.63 0.17-1.00
collection bag or collecting
urine sample
Oral care or nasal swab 0 0.71 0.32-1.00
Stool sample or rectal 1 (4) -- --
swab
Nebulizer treatments 2 (7) -- --
Procedures
BiPAP 1 (4) 0.32 0.01-0.66
Electrocardiogram 0 0.42 0.04-0.88
Insertion of central venous 0 -- --
catheter
Insertion of peripheral 0 0.75 0.43-1.00
intravenous catheter or
arterial catheter
Insertion of nasogastric 0 -- --
tube
Insertion of urinary (Foley) 0 -- --
catheter
Chest physiotherapy 0 -- --
Other
Cleaning room/furniture 0 0.65 0.02-1.00
Cleaning medical 2 (7) 0.51 0.03-0.99
equipment
* SARS, severe acute respiratory syndrome; CI, confidence interval;
BiPAP, bi-level positive air pressure.
This study was supported by grants from the Ontario Ministry of Health and Long Term Care and Health Canada. References (1.) Varia M, Wilson S, Sarwal S, McGeer A, Gournis E, Galanis E, et al. Investigation of a nosocomial outbreak of severe acute respiratory syndrome (SARS) in Toronto, Canada. CMAJ CMAJ - Canadian Medical Association Journal. 2003;169:285-92. (2.) Loeb M, McGeer A, Henry B, Ofner M, Rose D, Hlywka T, et al. SARS among critical care nurses, Toronto. Emerg Infect Dis. 2004;10:251-5. (3.) Scales DC, Green K, Chan AK, Poutanen SM, Foster D, Nowak K, et al. Illness in intensive-care staff after brief exposure to severe acute respiratory syndrome. Emerg Infect Dis. 2003;9:1205-10. (4.) Seto WH, Tsang D, Yung RW, Ching TY, Ng TK, Ho M, et al. Effectiveness of precautions against droplets and contact in prevention ofnosocomial transmission of severe acute respiratory syndrome (SARS). Lancet. 2003;361:1519-20. (5.) Landis RJ, Koch GG The measurement of observer agreement for categorical data. Biometrics. 1977;33:159-74. (6.) LeDell K, Muto CA, Jarvis WR, Farr BM. SHEA guideline for preventing nosocomial transmission of multidrug-resistant strains of Staphylococcus aureus and Enterococcus. Infect Control Hosp Epidemiol. 2003;24:639-41. (7.) Fowler RA, Guest CB, Lapinsky SE, Sibbald WJ, Louie M, Tang P, et al. Transmission of severe acute respiratory syndrome during intubation and mechanical ventilation. Am J Respir Crit Care Med. 2004;169:1198-202. (8.) Hawryluck L, Gold WL, Robinson S, Pogorski S, Galea galea aponeuro´tica the aponeurosis connecting the two bellies of the occipitofrontalis muscle. ga·le·a (g  l S, Styra
R. SARS control and psychological effects of quarantine, Toronto,
Canada. Emerg Infect Dis. 2004;10:1205-12.(9.) Maunder R, Hunter J, Vincent L, Bennett J, Peladeau N, Leszcz M, et al. The immediate psychological and occupational impact of the 2003 SARS outbreak in a teaching hospital. CMAJ. 2003;168:1245-51. (10.) Rothman KJ, Greenland S. Modern epidemiology. 2nd ed. Boston: Lippincott Williams and Wilkins; 1998. Popy Dimoulas, * Karen A. Green, * Altynay Shigayeva, * Michael Aquino, * Allison McGeer, * Damon C. Scales, * and Toronto SARS Hospital Investigation Team (1) * Mount Sinai Hospital, University of Toronto, Toronto, Ontario, Canada (1) B. Henry (Toronto Public Health), S. Paton (Health Canada), T. Stewart (Mount Sinai Hospital), D. Zoutman (Kingston General Hospital), J.M. Raboud and U.R. Saskin (Mount Sinai Hospital), M. Loeb (Hamilton Health Sciences Center), A.E. Simor and M. Vearncombe (Sunnybrook and Women's College Hospital), C. MacDonald (Centers for Disease Control and Prevention), E. Bontovics (Ontario Ministry of Health and Long Term Care) Ms. Dimoulas is an epidemiologist with the Infectious Diseases Control Division of the Regional Municipality of York, Ontario, Canada. Her research interests include infectious disease surveillance and response. Address for correspondence: Allison McGeer, Room 1460, Mount Sinai Hospital, 600 University Avenue, Toronto, M5G 1X5, Canada; fax: 416 586-3140; email: amcgeer@mtsinai.on.ca |
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