Intensive Care Units (ICU) treat patients with the most serious injuries and illnesses, most of which need close monitoring and support from specialist equipment and medication in order to maintain normal bodily functions. Highly trained doctors and critical care nurses who specialize in caring for severely ill patients staff ICUs.
In 1854, Florence Nightingale left for the Crimean War, where she triaged, or separated, the most seriously wounded soldiers from the less-seriously wounded. Her experiences formed the foundation for her later discovery of the importance of sanitary conditions in hospitals, a critical component of intensive care. In response to a polio epidemic (where many patients required constant ventilation and surveillance), the first ICU was established in Copenhagen in 1953.
The first application of this idea in the United States was in 1955 at the Dartmouth Medical Center. In the 1960s, the importance of cardiac arrhythmias in heart attacks led to the routine establishment of ICUs. Now, patients are admitted to an ICU if they require constant monitoring, immediately after invasive surgery, after accidents, with life threatening infections, or any other condition that is life threatening.
Dr. Priya Nair and colleagues of the Saint Vincent Hospital in Sydney, Australia, recently conducted a study on ICU patients and their vitamin D levels.
Nair P, Lee P, Reynolds C, Nguyen ND, Myburgh J, Eisman JA, Center JR. Significant perturbation of vitamin D-parathyroid-calcium axis and adverse clinical outcomes in critically ill patients. Intensive Care Med. 2012 Oct 13.
The authors conducted a prospective, multicenter cohort study of 100 consecutive patients obtained from three referral centers in Sydney, Australia who were expected to stay in the ICU for more than 2 days. In addition to routine blood investigations, levels of 25(OH)D were measured on day one, day three, and either at day seven or at ICU discharge if it came first.
Average vitamin D levels on ICU admission were about 15 ng/ml. The prevalence of severe vitamin D deficiency (< 20 ng/ml) was 55% and 24% of the patients had levels less than 10 ng/ml. Only 3% of patients had levels above 30 ng/ml. 25(OH)D levels were undetectable in 8% of the patients. Severity of illness scores were collected using three different standardized scales on day one, day three and either day seven or discharge from ICU, whichever was earlier.
In short, the authors found that vitamin D deficiency was associated with longer hospital stays. Admission 25(OH)D levels showed a modest correlation with two of the severity of illness instruments. These findings corroborate with past findings that I have written about before.
The authors concluded,
“In summary, low vitamin D levels are highly prevalent in critically ill adults with 78% of patients having either insufficient or deficient levels. Low levels of vitamin D and hyperparathyroidism were associated with increased severity of illness on ICU admission. Furthermore, low vitamin D levels were associated with fewer hospital-free days in univariate but not multivariate analyses after accounting for severity of illness.”
Furthermore, the authors recommended:
“While it remains to be determined whether low vitamin D status is causally implicated in the pathogenesis of critical illness co-morbidities, findings from this study highlight the imperative for future evaluation of dosing and safety regimens followed by randomized control trials of vitamin D in the ICU.”