Measurement of nausea

Abstract

Dr. Mary Barnes’ has written an excellent review on “nausea and vomiting in the patient with advanced cancer.” In addition to the pain suffered by the majority of cancer patients, nausea caused by chemotherapy, narcotics, or the disease process itself represents another torment to be endured by almost 50% of cancer patients. At a meeting on quality of life sponsored by the National Cancer Institute of Canada several years ago, I was dismayed by the prevalence of nausea among cancer patients, by the paucity of effective drugs to control it, and by the absence of valid, reliable measuring tools that can give us an idea of the intensity of nausea or the relative effectiveness of our therapies for different chemotherapy agents. Fortunately, shortly after the meeting, Morrow2 published an excellent review of procedures to assess nausea and vomiting. Emesis, of course, is simple to measure in terms of frequency and volume. Nausea is a greater problem. Like pain, it is a subjective experience and presents all the same problems inherent in measuring pain. Consequently I interviewed patients at the Chemotherapy Center at Montreal General Hospital and learned that patients had little trouble in describing the intensity of nausea using a visual analogue scale (VAS) or the descriptor scale of the Present Pain Intensity of the McGill Pain Questionnaire (MPQ),3 which, for the purposes of this investigation, I renamed the Overall Nausea Index (ONI). I also found that the patients, when asked to describe “what does your nausea feel like; what kinds of words can you use to tell me what you are feeling,” tended to use words in the descriptor lists of the MPQ. The study I subsequently carried out with Zeev Rosberger (clinical psychologist), M. Lois Hollingsworth (Head Nurse of the Chemotherapy Center), and Michael Thirlwell (Director of the Division of Medical Oncology) at Montreal General Hospital provided the basis for a “Nausea Questionnaire” and has been published.4 I wish to present a brief summary of it here because it provides simple, valid measures of nausea, which indicate that the problem of measurement of nausea should not deter us from seeking new, more effective drugs and procedures. It is not “the perfect measuring tool,” but it is at least a start, which can become a stepping stone toward more effective tools.