Patients Awaiting Coronary Bypass Surgery


It is argued that anxiety an uncertainty experienced by patients waiting for coronary bypass surgery affects the outcome of surgery. In 2006, McCormick and colleagues examined the interaction of symptom distress, anxiety, functional status, and uncertainty, and the effect of the period of waiting in the lights of Mishel’s Middle-Range Nursing theory of uncertainty of illness. This essay aims at critically examining this research article.

Research design

The study designed as a descriptive, correlational, and a cross-sectional study. The authors reviewed the literature on the severity of anxiety, changes of psychosocial condition in relation to the period of waiting, and symptoms of patients waiting for CABG. They obtained the approval of the education nursing ethics board, and local health authorities to access the study population. Patients scheduled for surgery were approached by mail including the study questionnaire (with an introductory letter). Supplementary data collection was semi structured questions through phone contact.

Conceptual framework

The authors choose Mishel’s Middle-Range Nursing theory of uncertainty of illness as a theoretical framework, where uncertainty results from lack of symptom experience and assessment (precursors to uncertainty). The theory recognizes uncertainty as indeterminate cognitive state, and nursing interventions in this condition should target helping patients to constructively adjust and manage uncertainty.

Instruments reliability

McCormick and colleagues selected four standard instruments, first is Mishel’s uncertainty illness scale whose reliability (consistency of measurements) was moderate to high as tested by coefficient alpha scores (reliability measuring of a psychometric instrument). The authors determined the scale measures (or correlates) with the uncertainty construct (scale validity construct) by the scale’s capacity to set apart medical, surgical, or diagnostic patients. Second instrument is symptom frequency and symptom distress scales, which subjectively measure symptom frequency and the level of recognized stress.

Reliability by correlating an item score to the total score, and correlations were statistically significant. Correlation measures the strength of association between two variables, is useful to explore the certainty of prediction.

Third instrument are two subscales of Kansas City cardiomyopathy questionnaire (a physical, and a social limitation scales). Both subscales were tested for reliability using alpha coefficient scores as with Mishel’s uncertainty illness scale, and correlations were statistically significant. Further the physical and social limitation subscales were validated by comparison with New York Heart Association functional status; correlations were significant for both subscales. The fourth instrument is Graphical Anxiety Rating scale, based on their review; the authors inferred this scale being a visual analog scale, is accurate and sensitive in measuring preoperative anxiety.

Study variables

The level of measurement of variables in this study was interval factors, which are quantitative variable characteristics that can be measured on interval scales (Campbell, 2006).

The variables assessed in this study were uncertainty, symptom distress, anxiety, functional status (physical, and social), and the duration of waiting for surgery. An independent variable is a known (predicted) and variations of this factor result in a change (related or not) in the dependent (response) factor (Campbell, 2006). As the authors clarified, uncertainty is the incapacity of a patient with a chronic illness to infer the outcomes of events correlated to the illness, symptom experience is a precursor to uncertainty, and functional status is an element of illness symptoms’ pattern. In this case uncertainty is a dependent variable while symptom distress and functional status are independent variable.

As explained in the study, Mishel’s Middle-Range Nursing theory of uncertainty suggests that anxiety is a result of uncertainty; in this case uncertainty is an independent variable while anxiety is a dependent one. When the authors examined the effect of the period of waiting on the other variables, all variables can be considered dependent on the duration of waiting for surgery, which in this case is the independent variable.

Results in the lights of previous research

Results of this study agreed with other studies in that uncertainty, anxiety, symptoms, and social and physical status are significant concerns of patients waiting for coronary bypass surgery. However, none of the variables showed significant correlation to the duration of waiting, in agreement with studies of larger sample size. In this respect, the study also showed that semi structured telephone interviews had the same results as mailing questionnaires.

Correlation results showed that anxiety, and symptoms distress correlate strongly with uncertainty. Functional status and anxiety did not have significant correlation with uncertainty. The symptom frequency and symptom distress scales did not display significant correlation with uncertainty and anxiety in agreement with results of Canadian Cardiovascular Society angina. The authors inferred the collective experience of symptoms that produce greater effect than a single symptom overshadowing others.

Implications to clinical practice

Based on their results, McCormick et al (2006) inferred that regular assessment of symptoms and functional status of patients waiting for coronary bypass helps stabilizing the patients’ cardiac condition. Further, it helps patients to identify symptoms of worsening of condition. Healthcare professionals need to recognize that patients differ in experiencing symptoms and levels if anxiety. Nurses need to identify that those patients experience fear from death because of a myocardial infarction; yet, at the same time they experience hope of having a successful surgery.

Therefore, nurses need to practice balance between these two opposing feeling and understand that anxiety affects the postoperative outcome of surgery in long and short terms. Thus, awareness of the effects of waiting on patients waiting for coronary bypass is an essential complementary to the holistic care of these patients.


Campbell, M., J. (2006). Statistics at Square Two: Understanding modern statistical applications in medicine (2nd edition). Sheffield: BMJ Books, Blackwell Publishing.

McCormick, K., M., Nairnark, B., J., and Tale, R., B. (2006). Uncertainty, symptom distress, anxiety and functional status in patients awaiting coronary artery bypass surgery. Heart & Lung, 35(1), 34-45.