ارزیابی ارگونومیک جلیقه نجات نوزاد: زمان پوشیدن وبادقت و صحت پوشیدن

Canada is considering the development of a new standard for infant/child life jackets. Eight currently available (approved and non-approved) infant/child life jackets were procured for evaluation. Fifty-six participants were chosen as a sample of convenience from the general public for testing. The life jackets were divided into two groups of four, which were donned on a soft infant manikin procured from the Red Cross. In 224 attempts at donning, only 43 (19%) attempts resulted in the life jacket being donned correctly in less than 1 min. Only one life jacket came close to a good design and passed the life jacket standard for donning time and accuracy. Failure rates were observed across all the participants irrespective of age, gender, experience with children and experience with recreational marine equipment. Accuracy and speed of donning the life jacket were hampered as the number of donning sub-tasks increased. It was concluded that it is possible to design a life jacket that can be donned correctly in under 1 min. The life jacket must be of simple, intuitive design and fall naturally into the anatomical shape of the child. A minimum number of ties, zips and clips should be used in the design, and if such connectors are used they should be color coded or of different shapes and sizes to avoid confusion.

Over the last 20 years, more and more adults own recreational watercraft and regularly infants/children accompany them. Due to the popularity of taking infants/children on maritime vacations, in 2010 the International Maritime Organization (IMO) intends to legislate the issuing of life jackets to infants/children on cruise liners and passenger ships for the first time (Safety at Sea International Magazine, 2008). Devices to prevent drowning are called life jackets or flotation aids in Europe and personal flotation devices (PFDs) in the U.S.A. In Canada, they are all referred to as life jackets and for the rest of this paper they will be referred to as such. In 1991, Funkhouser and Fairlie (1991) evaluated 4 infant life jackets and noted that confusing straps and buckles delayed donning. The device that was most quickly donned was an inflatable type with a mean donning time of 28.8 s. Brooks (1995) noted very little data had been published on infant/child life jackets and commented that “they appeared to be scaled down versions of their adult counterparts”. Subsequently, Coleshaw et al. (2001) published further data related to donning time. They found that fathers donned three of five different life jackets on children in a mean time of under 1 min, a fourth life jacket in a mean time of 72 s and a fifth life jacket in a mean time of 76 s. They found that children donned the life jackets on themselves in a mean time of 87 s, although they could not make the tightening adjustments and some could not tie a bow. Canada has just published a new life jacket standard (CAN/CGSB-65.7-2007), which includes infants/children, youths and adults in one standard (Canadian General Standards Board, 2007). The standard identifies two distinct Classes of life jackets and 3 sub-classifications of the Class 1 life jacket. The sub-classifications in Class 1 are infant/child (9–18 kg), youth (>18–40 kg) and adult (>40 kg) life jackets. For each life jacket sub-classification, there are mandatory buoyancy requirements of 30, 60, and 150 N for infants/children, youth and adult life jackets, respectively (Canadian General Standards Board, 2007). The section in the standard on infant/child life jackets specifies that where appropriate, the life jacket must accommodate infants/children between 9 and 18 kg in body mass and those with a chest circumference of equal to or less than 625 mm. The standard also makes specific reference to donning accuracy (donning a life jacket correctly), but there is no evidence in the literature to support the specific requirement of ≥80% of participants to perform a correct donning on the first attempt and 100% of participants to perform a correct donning on the second attempt. It seems as if these two requirements have been copied from previous Canadian and International standards (American Code of Federal Regulations, 2002, Canadian General Standards Board, 1988a, Canadian General Standards Board, 1988b, Canadian General Standards Board, 2007, European Committee for Standardization, 1993, European Committee for Standardization, 1993b, European Committee for Standardization, 1993c, International Maritime Organization (IMO), 2003, International Organization for Standardization (ISO), 2003, Underwriters Laboratories Inc., 1976, Underwriters Laboratories Inc., 1990 and Underwriters Laboratories Inc., 2000) and may not have been re-considered in the light of some new life jackets that have far more sub-tasks involved with their donning (ties, tapes, buckles, zips, etc.). For this reason it was not known whether a manufacturer who produces a very credible novel new infant/child life jacket might be penalized and the design rejected because, for instance the life jacket required a slightly longer donning time, but in return provided superior in-water performance. The purpose of the study is to layout a systematic methodology for the development and/or evaluation of standards of protective equipment that is based on the application of a human factors approach (Wickens et al., 2004). To conduct this study 4 steps were undertaken: 1) A review of current national and international life jacket standards for infants/children; 2) a review of the critical factors in these standards that are directly related to human factors issues; 3) the procurement of approved and non-approved representative infant/child life jackets available in Canada; and 4) the performance of a series of donning trials using the representative life jackets.

1. Fifty-six participants donned one or other of a group of 4 infant/child life jackets. Only 1 out of the 8 life jackets passed the Canadian standard for both donning time and accuracy. 2. If the life jacket did not appear to look like a simple vest that an infant/child would put on during their normal day-to-day routine, then it took longer to don it. 3. Accuracy and speed in donning the life jacket was severely reduced when the number of sub-tasks required for donning was increased. 4. Designing straps, buckles and tapes in a variety of different sizes and colours to avoid incorrect connections would increase the speed and efficiency of donning. 5. Failure rates were observed across all the participants and neither age, sex, experience with infants/children, nor experience with recreational marine equipment had any effect on this failure rate.