Vitamin B6 intakes and status of mechanically ventilated critically ill patients in Taiwan

Abstract

Objective: To assess vitamin B6 intake and status of critically ill patients. The relationship between vitamin B6 status indicators and the severity of illness and outcome in these patients was also examined. Design: Prospective clinical study. Setting: The study was performed at the Taichung Veteran General Hospital, in the central part of Taiwan. Subjects: Ninety-four patients in the intensive care unit (ICU) entered the study and 46 patients successfully completed this study. Interventions: No intervention. Main outcome measures: Vitamin B6 intake was recorded for 14 days. Vitamin B6 status was assessed by direct measures (plasma pyridoxal 5 0 -phosphate (PLP), pyridoxal (PL), and urinary 4-pyridoxic acid (4-PA)) and indirect measures (erythrocyte alanine (EALT-AC) and aspartate (EAST-AC) aminotransaminase activity coefficient). The severity of illness (APACHE II score), the length of ventilation dependency, and the length of ICU and hospital stay were recorded. Results: Patients had an adequate mean vitamin B6 intake (16.26 AE 19.39 mg) during the 14 day study. Mean vitamin B6 intake was significantly higher on day 14 than on day 1 (P < 0.001). However, plasma PLP and PL concentrations significantly decreased at the 14th day after admission (P < 0.05). Erythrocyte alanine aminotransaminase activity coefficient and EAST-AC did not change significantly. Urinary 4-PA significantly increased at the 14th day (P < 0.001). No significant relationships were found between APACHE II scores and clinical outcomes (the length of ICU and hospital stay, the length of ventilation dependency) of patients, vitamin B6 intake or status indicators. Conclusions: Critically ill patients received nutritional support in the ICU, and had sufficient mean vitamin B6 intake and adequate vitamin B6 status. Therefore, the severity of illness and the results should not be affected by vitamin B6 status. However, we have noted that plasma PLP and PL concentrations significantly decreased while vitamin B6 intake significantly increased on day 14. Critical clinical conditions and complex metabolism in the critically ill may account for the reduction of plasma PLP and PL. Since vitamin B6 deficiency causes profound effects on immune system function, dietary or supplemented vitamin B6 intake is suggested for hospitalized patients.

Vitamin B6 supplementation increases immune responses in critically ill patients

“…Quasim et al (2005), therefore, suggested that direct measurements of red cell PLP are more responsive to supplementation than plasma measurements in the critically ill patients. That might be the reason why there was no correlation between vitamin B 6 intake and plasma PLP concentration in our two previous studies (Huang et al, 2002;Huang et al, 2005). Critically ill patients consumed approximately 4 mg/day of vitamin B 6 , and a marginal plasma PLP deficiency (B20 nmol/l) and abnormal immune responses were still observed (Huang et al, 2005).…”

“…Our previous study (Huang et al, 2002) indicated that although critically ill patients had an adequate vitamin B 6 intake (1.6 mg/day for men and women who are older than 51 years, Taiwan Dietary Reference Intakes, Department of Health, Taiwan, 2002), their plasma PLP and pyridoxal (PL) still significantly decreased during their stay in the intensive care unit (ICU). Critically ill patients were under severe stress, inflammation, and clinical conditions, which may increase the utilization and metabolic turnover of plasma PLP or even cause the redistribution of PLP from plasma to erythrocyte (Louw et al, 1992;Talwar et al, 2003a;Huang et al, 2005).…”

Inadequate Vitamin B-6 Status in Critical Care

“…In the absence of evidence showing clinically inadequate vitamin B-6 intake in critically ill patients, deficient vitamin B-6 status in such patients in the intensive care unit may not be a concern. Although critically ill patients had an adequate vitamin B-6 intake, their plasma PLP concentration was observed to be significantly lower than that of healthy controls and decreased during their stay in the intensive care unit (Huang et al 2002;Huang et al 2005). Critically ill patients are under severe stress, with severe inflammation status and clinical conditions, and may therefore increase the utilization and metabolic turnover of plasma PLP.…”

“…In contrast, critically ill patients often receive nutritional support (enteral, parenteral, or combined nutrition) or get micronutrient supplements, and thus they might have sufficient mean vitamin B-6 intake with a mean intake ranging from 2.4 to 16.3 mg/day (Cheng et al 2006;Huang et al 2002;Huang et al 2005). In the absence of evidence showing clinically inadequate vitamin B-6 intake in critically ill patients, deficient vitamin B-6 status in such patients in the intensive care unit may not be a concern.…”

“…The vitamin B-6 status (i.e., plasma PLP) of critically ill patients was shown to be significantly lower than that of healthy controls and decreased during their stay in the intensive care unit (Huang et al 2002;Huang et al 2005). Pyridoxal 5 0 -phosphate and PL are both bound to serum albumin, with the PLP binding more tightly, while being transported by the blood.…”