are anesthetics safe The National Halothane Study was a major investigation of t
ID: 3174419 • Letter: A
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are anesthetics safe The National Halothane Study was a major investigation of the safety of anesthetics used in surgery. Records of over 850,000 operations performed in 34 major hospitals showed the following death rates for four common anesthetics:^8 There seems to be a dear association between the anesthetic used and the death rate of patients. Anesthetic C appears to be dangerous. Explain why we call the National Halothane Study an observational study rather than an experiment, even though it compared the results of using different anesthetics in actual surgery. When the study looked at other variables that are confounded with a doctor's choice of anesthetic, it found that Anesthetic C was not causing extra deaths. Suggest several variables that are mixed up with what anesthetic a patient receives.Explanation / Answer
a. The data was collected after the anesthesia was administered.
In an observational study, investigators observe subjects and any treatment that the subjects receive are beyond the control of the investigators. Here the anaesthetics used are determined by the doctors and the investigators are simply observing.
b. Anesthetic C could be used for surgeries that have a higher risk of complications, leading falsely to conclude that the anesthetic caused the deaths, when the true cause was related to the type of illness.
The severity of the patients' illnesses is also likely a lurking variable.
Different anesthesiologists may prefer to use different anesthetics so there may be differences due to the surgeons.
Type of surgery, length of surgery (maybe longer operations require anesthetic C), age of patient (maybe older patients respond better to anesthetic C), patient allergy to certain anesthetics, how healthy the patient was before the surgery are all possible confounding variables
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