- Author/Harry Collins, Trevor Pinch (Harry Collins, Trevor Pinch)
- Translator/Li Shangren
Assessing survival rate is not an easy task
Until today, the United States has not fully known the survival rate of cardiopulmonary resuscitation. Without a national database, medical researchers and policy makers have no way of knowing how many people have undergone cardiopulmonary resuscitation. Researchers must rely on the regional survival rates estimated by short-term small-scale studies. Such numbers usually vary greatly.
A study compared the survival rates after cardiopulmonary resuscitation in 29 cities in the United States from 1967 to 1988, and found that the gap ranges from 2% in Iowa to gold in Washington. Twenty-six percent of Eun County.
In general,These survival rates are in sharp contrast to the optimism of 1973. These studies also confirm that CPR has established its popularity at this time. The general public learns CPR. In several communities, more than half of the resuscitation is carried out by passers-by. In addition, most emergency medical systems have been successfully reorganized.
Why is the survival rate different?
Researchers are beginning to worry about what factors are causing such a difference in survival rates? Iowa’s 2% survival rate means that only one out of every fifty recovery efforts will succeed; in Seattle, on average, one out of every four attempts can save the opponent. However, to understand the significance of these numbers, the survival rates of resuscitation in Seattle and Iowa must be calculated using the same baseline.
Take response time, a variable known to affect survival, as an example. This is the time between passing out and starting the resuscitation. However, the literature does not have a clear definition of “reaction time”. Just like Mickey. Dr. Mickey Eisenberg noticed when reviewing the literature that it may include all or part of the following actions: identification, decision to call for help, phone call, dispatch center for questioning, dispatch, rush to emergency station The scene, from the scene to the patient’s side (Eisenberg, quoted from Timmermans, 70).
In addition to reaction time, Eisenberg also found that the definitions of basic terms such as “heart stop”, “passengers performing cardiopulmonary resuscitation”, “others noticed heart stop”, “ventricular fibrillation” and “admission to hospital” are different. In terms of effective comparison, it is more important that researchers have different definitions of the two key elements of survival, resuscitation and survival.
Some people define any attempt to perform cardiopulmonary resuscitation as an effort to resuscitate, while others limit this to specific heart rhythm problems, such as ventricular tachycardia.
“Survival” is also a vague word. In some studies, it means that there is only a slight neurological injury when discharged from the hospital; other studies refer to the survival pulse when entering the intensive care unit. If you add in the inevitable differences between the regional medical systems, it is obviously more difficult to interpret the survival rate.
Before quantifying the effect of cardiopulmonary resuscitation, let’s unify the standards!
In order to overcome this ubiquitous definition problem, the Utstein Consensus Conference was held in the Utstein Monastery on a small island off the coast of Norway in 1990. The definition was standardized and a uniform survival rate was proposed. Calculation formula.
The new formula is that “the denominator is the number of people who have stopped their heartbeats due to ventricular tremor caused by heart disease, and the numerator is the number of people[ill]who are discharged[from the hospital]and are still alive” (Timmermans, 73). In other words, the patient must have had heart problems before, and not caused by other events such as drowning or electric shocks.
This definition of survival rate is much narrower than the one used before. It excludes many incidents and accidents (including drowning), which have been regarded as the scope of resuscitation in the past two centuries. In addition, it also excludes patients who have not witnessed a heartbeat stop, and who did not perform the first cardiopulmonary resuscitation by bystanders. Since this definition only includes those cases with the best chance of survival, the estimated survival rate will be much larger than that of studies that use a broader definition.
In fact, most conditions that would use CPR (60 to 80% of all cases) are now excluded from the statistics. On the other hand, patients who were alive at the time of discharge are included in the calculation.The survival rate created by such a standard is relatively high, Although the discharge standards of hospitals in the United States and even the world are not consistent.
The final effect is still not optimistic
Since 1991, some studies have been conducted according to Utstein’s standards. Although the healthiest and most homogeneous samples were selected,Survival rates are still disappointingly low, and there are still big differences.
For example, a study conducted in Chicago found that the survival rate for African Americans was 0.8%, while the survival rate for whites was 2.6%. The title of this research result is quite appropriate: “Results of Cardiopulmonary Resuscitation in Metropolitan Areas-Where Are the Survivors?” > The survival rate in New York City is very low, only 1.4%.
On the other hand, Oakland County, Michigan has a 14.9% survival rate. As Timomans pointed out (74), the medical literature always makes optimistic interpretations of numbers. The low survival rate is blamed on the poor quality of medical services in the metropolitan area. Proponents of cardiopulmonary resuscitation argue that as long as there is a more mature first aid system and the necessary political will, any place should be able to achieve a survival rate as high as 30% in Seattle.
Early defibrillation is seen as the key to improving survivalSome studies indicate that 80% to 90% of survivors have received treatment for ventricular fibrillation, which is not a technique that passers-by can have without the assistance of others. The current strategy adopted by the United States is to increase the popularity of defibrillators, so that they are now standard equipment in airplanes, gyms, offices, and other places, just like fire extinguishers.
Survival numbers with defibrillation are slightly better than other statistics; however, there are differences between regions, andThere is very little convincing evidence of a breakthrough in survival。
Maybe Timomans made a profound argument about statistics.He believes that because the medical community and the general public have a lot of faith in CPR,No matter how low the statistics are, they cannot compromise the notion that it is valid。
The poor survival rate is interpreted as meaning that emergency medical services and medical infrastructure need to be improved to get a better survival rate. As for the effectiveness and necessity of cardiopulmonary resuscitation, it is rarely questioned.
Even the American Heart Association, which strongly supports cardiopulmonary resuscitation, admitted in 1991 that only 1% to 3% of people who were discharged from the hospital after the heartbeat stopped, and because of poor data quality, the real The percentage of “maybe lower” (Timmermans, 4).
——This article is excerpted from “The Tension of Medicine”, September 2021, Left Bank Culture.