To the Editor:
Ideal ICU physician staffing remains a topic of ongoing debate, with studies presenting conflicting results regarding the benefit of 24/7 intensivist coverage. We read the article in CHEST (April 2015) by Kerlin and colleagues1 with great interest. The authors reported no mortality benefit with intensivist presence in the ICU, but, surprisingly, also found lower adjusted mortality for nonphysician ICUs when compared with other staffing models.
The authors suggest that overly aggressive care and a failure to transition toward end-of-life care may contribute to the perceived “benefit” of nonphysician ICUs. While we agree that this likely contributes to the observed effect, we wonder if the authors considered two additional hypotheses that may partially explain their surprising findings.
As the authors have expertise in the impact of hospital transfers on artificially lowering ICU mortality,2 we wonder if they explored the role of transfers in explaining the association between staffing and mortality seen in their study cohort. Nonphysician ICUs are more common in lower volume, community hospitals.3 Studies show that hospital concerns about public reporting of mortality result in more acute-care transfers for critically ill patients.4 It is plausible that sicker patients cared for in nonphysician ICUs in the study by Kerlin and colleagues,1 given their higher severity of illness, were more likely to be transferred to higher-level care centers, making mortality appear “better” at nonphysician hospitals. This residual confounding by severity of illness in patients transferred from outside hospitals to intensivist hospitals may mask some of the effect of ICU staffing on subsequent mortality.
Additionally, we question how the use of telemedicine was defined in the ICU staffing models. ICU telemedicine has increased dramatically in US ICUs. Studies of tele-ICU care suggest that remotely delivered ICU care may be of particular benefit in smaller community hospitals without a physician presence, with greatest benefit seen among the sickest patients.5 It is possible that use of telemedicine, if not defined as physician staffing, may have led to misclassification of physician involvement, altering the overall results. It is unclear to what degree this misclassification may have impacted the study results.
We commend the authors for the scope of their study and welcome its contribution to our understanding of the relationship between ICU staffing and mortality. We hope that the considerations raised in this letter will further our understanding of the complex relationships between organizational care factors and patient outcomes.
Footnotes
FINANCIAL/NONFINANCIAL DISCLOSURES: None declared.
References
- 1.Kerlin M.P., Harhay M.O., Kahn J.M., Halpern S.D. Nighttime intensivist staffing, mortality, and limits on life support: a retrospective cohort study. Chest. 2015;147(4):951–958. doi: 10.1378/chest.14-0501. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 2.Kahn J.M., Kramer A.A., Rubenfeld G.D. Transferring critically ill patients out of hospital improves the standardized mortality ratio: a simulation study. Chest. 2007;131(1):68–75. doi: 10.1378/chest.06-0741. [DOI] [PubMed] [Google Scholar]
- 3.Angus D.C., Shorr A.F., White A., Dremsizov T.T., Schmitz R.J., Kelley M.A., Committee on Manpower for Pulmonary and Critical Care Societies (COMPACCS) Critical care delivery in the United States: distribution of services and compliance with Leapfrog recommendations. Crit Care Med. 2006;34(4):1016–1024. doi: 10.1097/01.CCM.0000206105.05626.15. [DOI] [PubMed] [Google Scholar]
- 4.Reineck L.A., Le T.Q., Seymour C.W., Barnato A.E., Angus D.C., Kahn J.M. Effect of public reporting on intensive care unit discharge destination and outcomes. Ann Am Thorac Soc. 2015;12(1):57–63. doi: 10.1513/AnnalsATS.201407-342OC. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 5.Venkataraman R., Ramakrishnan N. Outcomes related to telemedicine in the intensive care unit: what we know and would like to know. Crit Care Clin. 2015;31(2):225–237. doi: 10.1016/j.ccc.2014.12.003. [DOI] [PubMed] [Google Scholar]