The effects of reduced caloric intake on ventilatory drive were investigated in normal volunteers. During a 10-day semistarvation period, 6 subjects (group 1) received parenterally an amino acid solution providng 550 kcal/d sufficient to prevent a negative nitrogen balance. Six subjects (group 2) received in addition a safflower oil solution providing a total caloric intake of 1,100 kcal/d. Hypoxic ventilatory drive was estimated by an index (parameter A) of the relation between minute ventilation (V̇(E)) and hypoxia. In group 1, mean values (± SEM) of A decreased significantly from 161.5 (± 42.0) to 48.9 (± 12.0) by day 10 (p <0.05), indicating a severe depression of hypoxic drive despite a positive nitrogen balance. In group 2, A did not change significantly (p >0.05) from control values indicating a preserved hypoxic ventilatory drive. In both groups, the slopes of the line relating V̇(E) to arterial PCO2 (ΔV̇(E)/ΔPaCO2) did not change significantly during the 10-day semistarvation period consistent with preservation of the hypercapnic ventilatory drive. These data indicate that during periods of starvation, parenteral administration of aminoacids in an amount sufficient to maintain nitrogen balance is inadequate to prevent depression of respiratory control mechanisms unless a minimum daily caloric intake is achieved.
ASJC Scopus subject areas
- Pulmonary and Respiratory Medicine
- Critical Care and Intensive Care Medicine
- Cardiology and Cardiovascular Medicine