To the editor:

The integrating and synthesizing work on middle-range theories reported by Lenz, Suppe, Gift, Pugh, and Milligan [1] in Advances in Nursing Science 17:3 raises interesting questions about how nursing theories should be developed. For several years, I have followed the work on childbearing fatigue and dyspnea because I believed them to be middle-range theories in the making. In reading about work to combine the two models into a theory of unpleasant symptoms, I have concerns that the accessibility to clinicians of these evolving theories may be lost.

I realize that the proliferation of very specific theories is problematic, but the separate theories both have broad ranges of generalization. Both lines of work have produced multiple, related concepts that begin to explain the dynamics of these two clinical phenomena. Also, the separate theories are reflective of patients' experiences and specific enough to guide interventions; both characteristics would be difficult to preserve in a more general theory.

I would be interested in learning of the authors' reason for combining them as opposed to continuing to empirically develop them as separate middle-range theories.

Sarah Jo Brown, RN, PhD

University of New Hampshire; Durham, New Hampshire

REFERENCES