Each year in Canada, about 10,000 children are admitted to the pediatric intensive care unit (PICU) for everything from elective surgery to pneumonia to meningitis. The average length of stay, for those who survive, is about 4 days. I remember my days on the PICU in medical school and perhaps only my stay on the pediatric burn unit was harder on my heart.
Researchers from the University of Ottawa led by Dr J Dayre McNally wanted to know if vitamin D levels had any interaction with length of stay or various treatment needs for these children, such as emergency (bolus) IV fluids or medications (catecholamines) to maintain blood pressure. They measured vitamin D levels on 326 children, average age about 4 years old, while they were admitting them for a variety of medical conditions. Then they analyzed the records of the surviving children to see if vitamin D levels predicted severity of illness or the need to use various life-saving measures.
McNally JD, Menon K, Chakraborty P, Fisher L, Williams KA, Al-Dirbashi OY, Doherty DR; on behalf of the Canadian Critical Care Trials Group. The Association of Vitamin D Status With Pediatric Critical Illness. Pediatrics. 2012 Sep;130(3):429-436. Epub 2012 Aug 6.
First, they reported that the average vitamin D level of healthy Canadian children is about 30 ng/ml, but they found that 92% of the children admitted to the PICU had levels less than 30 ng/m and 69% had levels less than 20 ng/ml.
Next, they found that low vitamin D levels were associated with a greater length of stay in the PICU, greater need for catecholamine medication to maintain blood pressure, greater need for mechanical ventilation, more life-threatening low blood calcium levels, and a greater need for emergency (bolus) IV fluids. A vitamin D level less than 20 ng/ml resulted in an almost 2 day longer length of stay in the PICU. For every 4 ng/ml decrease in vitamin D levels, PICU stay increased by about a half day.
The authors concluded:
“Data from this multicenter prospective study strongly suggests that the majority of critically ill Canadian children are vitamin D deficient at PICU admission. Furthermore, lower 25(OH)D levels are associated with greater catecholamine requirements, fluid bolus administration, hypocalcemia and longer PICU admission. Subsequent prospective interventional trials are required to establish whether rapid restoration of vitamin D stores has an impact on critical illness disease course and outcome.”
I was disappointed that there was no word about treating the vitamin D deficiency in these kids, in spite of knowing they have a worse prognosis. You see evidence based medicine requires that we wait for randomized controlled trials before we treat these children, which is why evidence based medicine is fine for scientists and unethical for physicians. Physicians are required to act, and have always been required to act, based on what is known today, not on what may be discovered in the future.