Flow-directed Pulmonary Artery Catheterization

Flow-directed pulmonary artery catheterization is a mainstay of critical care. Reasoned, but not necessarily justified, demands for a moratorium on its use1Robin ED Death by pulmonary artery flow-directed catheter. [editorial].Chest. 1987; 92: 727-731Crossref PubMed Google Scholar, 2Robin ED Hazards of the Swan-Ganz catheter [letter].Ann Intern Med. 1988; 108: 151Crossref PubMed Scopus (5) Google Scholar now call for an appropriate response. In 1980, an analysis of invasive monitoring concluded that in addition to many known complications and hazards, all intravascular instrumentation tends to impose a physiologic burden that changes the patient's reactivity to disease and to physiologic and pharmacologic challenges.3Spodick DH Physiologic and prognostic implications of invasive monitoring: Undetermined risk/benefit ratios in patients with heart disease.Am J Cardiol. 1980; 46: 173-175Abstract Full Text PDF PubMed Scopus (47) Google Scholar This was the impetus for a retrospective investigation of 3,000 patients admitted to the University of Massachusetts Medical school-affiliated hospitals that indicated possible lack of net benefit—and implying potential harm—from flow-directed pulmonary artery catheterization during acute myocardial infarction.4Gore JM Goldberg RJ Spodick DH Alpert JS Dalen JE A community-wide assessment of the use of pulmonary artery catheters in patients with acute myocardial infarction.Chest. 1987; 92: 721-727Crossref PubMed Scopus (292) Google Scholar A ‘go-with’ editorial1Robin ED Death by pulmonary artery flow-directed catheter. [editorial].Chest. 1987; 92: 727-731Crossref PubMed Google Scholar demanded a moratorium on the procedure based on a free extrapolation from the University of Massachusetts study figures that suggested an excessive death rate ascribable to the catheters. The authors of the investigation, however, had emphasized that the study was entirely retrospective (although matched) and at best exploratory. Since then, the investigation and editorial have entered the public domain5Schwartz M The catheter question. Press-Enterprise, Riverside, CAOct 12, 1987: C-1Google Scholar, 6US News and World Report, Nov 23, 1987; 65Google Scholar and, subsequently, the formal malpractice analyses of law firms.7Vevaina J Cardiac catheters: Doing more harm than good?.Med Malpractice. 1987; 5: 1-6Google Scholar Although the dangers of extrapolation from nonprospective and nonrandomized studies have long been known, a physician who is convinced that a modality may be dangerous is in a position entirely consistent with the proposal for a moratorium. On the other hand, if the data can be considered inconclusive, then the position would be one favoring further study. The 1980 article analyzing intravascular instrumentation also carried an original proposal for a randomized controlled trial of flow-directed pulmonary artery catheterization.3Spodick DH Physiologic and prognostic implications of invasive monitoring: Undetermined risk/benefit ratios in patients with heart disease.Am J Cardiol. 1980; 46: 173-175Abstract Full Text PDF PubMed Scopus (47) Google Scholar This was not adopted, but the question of a moratorium may force the issue. Moreover, the widespread use of the catheters places cardiology and critical care in the classic position of the genie having escaped from the bottle, and it will be difficult to convince many, if not most, users of these instruments, that, at least on balance, they might not be helpful, particularly in the context of only a single and retrospective study. Indeed, recently a distinguished investigator of the hemodynamics of acute care has supported the moratorium.8Russell Jr, RO Swan-Ganz [commentary].Patient Care. 1988; 22: 39Google Scholar What, then, can be done in this context? A randomized controlled trial remains an option. The reason the genie is out of the bottle is that an appropriately designed randomized controlled trial was not done ab initio9Spodick DH Randomize the first patient: Scientific, ethical and behavioral bases.Am J Cardiol. 1983; 51: 916-917Abstract Full Text PDF PubMed Scopus (32) Google Scholar which is the principal way to keep such genies bottled. However, better late than never, and the proposal for a controlled trial3Spodick DH Physiologic and prognostic implications of invasive monitoring: Undetermined risk/benefit ratios in patients with heart disease.Am J Cardiol. 1980; 46: 173-175Abstract Full Text PDF PubMed Scopus (47) Google Scholar could now be invoked as a compromise between a draconian moratorium1Robin ED Death by pulmonary artery flow-directed catheter. [editorial].Chest. 1987; 92: 727-731Crossref PubMed Google Scholar, 2Robin ED Hazards of the Swan-Ganz catheter [letter].Ann Intern Med. 1988; 108: 151Crossref PubMed Scopus (5) Google Scholar, 8Russell Jr, RO Swan-Ganz [commentary].Patient Care. 1988; 22: 39Google Scholar and remaining at the status quo. Moreover, since there is a widespread presumption (in which I join) of very frequent, if anecdotal, success with flow-directed catheters, a trial could be justified to refine indications for their use, as well as to investigate their safety. A straightforward clinical trial could be accomplished by entering each patient in whom the question of bedside pulmonary artery catheterization arises into such an investigation via a relatively simple mechanism: in each hospital a committee of three experts would pass on every proposed non-emergent catheterization. A unanimous ‘yes’ or ‘no’ would allocate the patient, but if a single member of the panel dissented, the patient would then be randomized. This approach might only slowly yield results, but if a sufficient number of institutions collaborated, and with careful follow-up and central quality control, another step might be taken to advance this critical issue beyond the point where the University of Massachusetts group and the moratorium proposers have left it. The results might be conclusive on their own, but should there be imbalances in baseline characteristics between those randomized to catheterization and those not, a basis would be established to continue further with a formal randomization of patients in predetermined categories, or, on the other hand, to leave the situation where it is at present. However, even the possibility of intrinsic harm, or at least no net benefit, from bedside pulmonary artery catheterization dictates that clarification must be undertaken—not because it is in the public domain5Schwartz M The catheter question. Press-Enterprise, Riverside, CAOct 12, 1987: C-1Google Scholar, 6US News and World Report, Nov 23, 1987; 65Google Scholar and in the dark recesses of law firms,7Vevaina J Cardiac catheters: Doing more harm than good?.Med Malpractice. 1987; 5: 1-6Google Scholar but rather for humanitarian and scientific reasons.