Weak link in re­sus­ci­ta­tion

The Guardian (Charlottetown) - - OPINION - BY DES COLO­HAN GUEST OPIN­ION Des­mond Colo­han is a re­tired Is­land physi­cian who spent much of his ca­reer as an emer­gency physi­cian and in pre-hos­pi­tal emer­gency med­i­cal sys­tems in the U.S.A. and Canada.

In a re­cent opin­ion piece in The Guardian, the au­thor says that our pre-hos­pi­tal car­diac ar­rest sur­vival rate is far worse than in more pro­gres­sive coun­tries, such as Aus­tralia, the U.S. and the UK. Really? Ac­cord­ing to a re­cent meta-anal­y­sis, pub­lished in the Amer­i­can Heart As­so­ci­a­tion’s jour­nal “Cir­cu­la­tion,” sur­vival from out-of-hos­pi­tal car­diac ar­rest (OHCA) world­wide has not sig­nif­i­cantly im­proved in al­most 30 years.

The ag­gre­gate sur­vival rate [those who make it through their hos­pi­tal­iza­tion and get dis­charged home, mostly in­tact, is be­tween 6.7 per cent and 8.4 per cent. This lack of progress, de­spite enor­mous in­creases in re­sus­ci­ta­tion re­search, the in­tro­duc­tion of new drugs and de­vices, and pe­ri­odic re­vi­sions to clin­i­cal guide­lines may be ex­plained, in part, by de­clin­ing num­bers of ven­tric­u­lar fib­ril­la­tion car­diac ar­rests, in­creas­ing age of the pop­u­la­tion, and longer EMS re­sponse times.

Seat­tle, Phoenix, Min­neapo­lis and Tokyo have sur­vival rates two to three times higher than av­er­age. Such cen­tres of ex­cel­lence have many things in com­mon: high pop­u­la­tion den­si­ties, ge­o­graph­i­cally small re­sponse cov­er­age zones, high per­cent­age of CPR-trained adults, tiered EMS re­sponse and so­phis­ti­cated no­ti­fi­ca­tion sys­tems, in­clud­ing use of so­cial me­dia.

All Seat­tle fire­fight­ers are trained as Emer­gency Med­i­cal Tech­ni­cians (EMTs) and act as first re­spon­ders; there are nearly 300 fully trained paramedics and 26 am­bu­lances on duty; there are au­to­mated ex­ter­nal de­fib­ril­la­tors in mul­ti­ple pub­lic lo­ca­tions, in­clud­ing many po­lice cars and all den­tal of­fices.

Seat­tle EMS re­sponds with at least three ve­hi­cles to each car­diac ar­rest, giv­ing a min­i­mum of seven EMTs on-scene, pro­vid­ing a highly or­ga­nized ‘pit crew’ re­sponse. Re­sus­ci­tated pa­tients who re­gain a pal­pa­ble pulse (ROSC) are rapidly trans­ported to hos­pi­tals which are set up to pro­vide im­me­di­ate ac­cess to an­giog­ra­phy and an­gio­plasty, life­sav­ing pro­ce­dures not avail­able on P.E.I..

The same study found that OHCA vic­tims who re­ceive CPR from a by­stander or an EMS provider, and those who are found in ven­tric­u­lar fib­ril­la­tion (VF) or ven­tric­u­lar tachy­car­dia (VT), rhythm dis­tur­bances amenable to ap­pli­ca­tion of an au­to­mated ex­ter­nal de­fib­ril­la­tor (AED), are much more likely to sur­vive than those who do not. Chances of sur­vival were sig­nif­i­cantly in­creased when a de­fib­ril­la­tor was avail­able at pub­lic sites. It is note­wor­thy that only 40 per cent of pa­tients with OHCA were found in VF/VT, and only 22 per cent of them achieved re­turn of spon­ta­neous cir­cu­la­tion (ROSC).

To put th­ese ob­ser­va­tions in con­text, ap­prox­i­mately one of ev­ery five pa­tients with VF/VT sur­vives to hos­pi­tal dis­charge, com­pared to one of ev­ery 250 pa­tients found in asys­tole. Prompt ini­ti­a­tion of CPR can de­lay the degra­da­tion of VF and VT to asys­tole, which may ex­plain why by­stander CPR and pre-hos­pi­tal de­fib­ril­la­tion have such a pos­i­tive im­pact on sur­vival. Fu­ture ef­forts to boost OHCA sur­vival should fo­cus on im­me­di­ate ini­ti­a­tion of CPR and early de­fib­ril­la­tion. Tar­geted CPR train­ing will have its great­est ef­fect in com­mu­ni­ties with cur­rently low rates of sur­vival.

Good out­comes de­pend on an in­ter­lock­ing se­ries of events oc­cur­ring rapidly and ef­fec­tively. When even one link is weak or miss­ing, it can’t be com­pen­sated for else­where. Ad­vanced life sup­port and rapid ac­cess to a car­diac cen­tre are of no use to a pa­tient who has been in car­diac ar­rest with­out ba­sic life sup­port for more than ten min­utes. We know that ev­ery minute with­out CPR be­fore de­fib­ril­la­tion means an al­most 10 per cent de­crease in sur­vival, and that we get the big­gest bang for our buck from im­me­di­ate and ef­fec­tive CPR fol­lowed by de­fib­ril­la­tion.

In most car­diac ar­rests, the weak link is prompt by­stander CPR. Un­for­tu­nately, in­ter­ven­tion only helps if the car­diac ar­rest is wit­nessed. Un-wit­nessed car­diac ar­rests are al­most al­ways fa­tal. If high-qual­ity by­stander CPR is started im­me­di­ately, chances of suc­cess­ful de­fib­ril­la­tion in­crease sig­nif­i­cantly.

Re­al­is­ti­cally, suc­cess­ful re­sus­ci­ta­tion from pre-hos­pi­tal car­diac ar­rest is lim­ited to wit­nessed car­diac ar­rest, where the vic­tim is in ven­tric­u­lar fib­ril­la­tion or ven­tric­u­lar tachy­car­dia, the wit­ness is trained to per­form and promptly ini­ti­ates ef­fec­tive CPR, there is ap­pli­ca­tion of an AED within 10 min­utes, cir­cu­la­tion is re­stored and rapid trans­fer to a car­diac cen­tre oc­curs. In a mostly ru­ral prov­ince with only 165 pre-hos­pi­tal car­diac ar­rests a year, less than half of whom have a rea­son­able shot at suc­cess­ful re­sus­ci­ta­tion and mean­ing­ful sur­vival, im­prov­ing on the norm will be a mon­u­men­tal chal­lenge.

Newspapers in English

Newspapers from Canada

© PressReader. All rights reserved.