Essential Emergency and Critical Care: a consensus among global clinical experts by Schell, CO, Khalid, K, Wharton-Smith, A, Oliwa, J, Sawe, HR, Roy, N, Sanga, A, Marshall, JC, Rylance, J, Hanson, C, Kayambankadzanja, RK, Wallis, LA, Jirwe, M, Baker, T