Ebola: Improving the Design of Protective Clothing for Emergency Workers Allows Them to Better Cope with Heat Stress and Help to Contain the Epidemic

摘要: It is a complex task to find optimal protective clothing prevent the spread of Ebola virus disease (Martin-Moreno et al., 2014; Ryschon, 2014). The fear getting infected an obstacle for recruiting healthcare workers. In addition, current design might curtail their working capacity severely in hot and humid climate West Africa and, paradoxically increase risk infection. Emergency work full including respiratory mask may lead extreme heat stress climates resulting shortened time, dehydration, reduced professional judgement, exhaustion. This increases infection health stuff (WHO, 2014). In Monrovia, Liberia, daytime maximum temperatures end year often reach 30–31°C, will be higher January May, season (Kjellstrom http://climatechip.org/). order manage this stress, workers need breaks 2009). leads frequent remove gear, which involves increased multiple steps suit can take up 30min (Kitamura, 2014). The modified Predicted Heat Strain (ISO 7933, 2004) model was used indicate expected times (Fig. 1). estimation made based on following assumptions. Standard man chosen calculations. Medium heavy activity (300W) taken as average rate. core temperature limit cease such emergency set 38.5°C. Three types with different moisture permeability (i m) were selected comparison: impermeable outer layer m = 0.00), semipermeable 0.07), relatively tight but still permeable 0.20). basic insulation all cases theoretically 1 clo (0.155 m2K W−1) comparative purposes. air conditions, other environmental factors kept constant. Ambient water vapour pressure 3.0 kPa, velocity/body motion s−1, there assumed no radiation effect present (work indoors or shade). 1 Continuous rate 300W at before reaching 38.5°C m). The load allows 40min shorter exposure during hottest periods 1) until exceeds suggested safe occupational exposure. Higher associated decreased mental performance misjudgement mistakes (O’Neal Bishop, 2010). Maximizing minimizing layers worn beneath provided that it should resistant penetration by body fluids, simple way preventing increasing time spent inside gear. However, dehydration intake must also considered extended exposures. A management program rehydration essential part overall safety any case. A desirable addition would personal cooling clothing, vests ice phase change materials (PCMs; Gao, 2014) filtered ventilated coveralls (Kuklane 2012). prolong about 2h reduce number gear changes per day. With 2-h required personnel could halved possible decrease contaminated waste. final choice method depends specific humidity. Increasing especially, humidity do effectiveness benefits PCM products. The use PCMs requires freezers cool areas solidification after use. Cooling are cheapest electricity required. Power one resources provide cope epidemics. Otherwise, PCM, e.g. Glauber’s salt organic hydrocarbons/wax, melting/solidifying 28°C available. For workers’ recovery exposure, room below 27°C recommended. connected facilities storage. If unavailable, then melted solidified cooler bath (using underground/well water, etc.), underground cave area night. melting are, less effective is. if gradient 6°C greater, effect. Considering garments, flow above 100 l min−1. There fan systems available market flows 200 min−1 battery power lasting least 5–8h (recharging takes 2h). Ventilated (positive suits) allow even drinking more. Table gives rough cost comparison future system 1-day (8-h) shift. into account only equipment cost. Estimation predictions given Fig. periods, i.e. new prolongs period device. both cases, similar Also, sets dressing, undressing, require between periods. As seen new, 10 more expensive solution almost 3 day. Table 1. Comparison possible, Assumed system. donning, doffing, ... Simultaneously, actively cover workstation halved. have extra (about 30min) shifts help tasks additional recovery. Due fewer dressing–undressing (16 + 16 versus 4 respective system), assistance disinfection these waste amounts products cleaned. meant reusable (extra costs decontamination procedures considered) compared present, supposedly disposable systems, already 2.5 reuse estimated prices. Infection risks diminished due undressing cleaning procedures. In conclusion, reducing among front-line allowing doubling critical factor successfully contain epidemic. Considering epidemic not last, warmer epidemics becoming frequent, conditions fight them severe (IPCC, 2013), testing evaluation selection long missions out.