Biomaterial Database

Utilization of indirect calorimetry to assist in determining undiagnosed hypothyroidism in a patient on mechanical ventilation. 2021

Michaelann Hahn, and Rebecca Brody

Department of Clinical and Preventive Nutrition Sciences, School of Health Professions, Rutgers University, Newark, New Jersey, USA.

Published predictive equations are required when indirect calorimetry (IC) is unavailable in the clinical setting. Several medical conditions that are not accounted for by published predictive equations can impact a patient's resting energy expenditure, such as adrenal changes or alterations in thyroid-stimulating hormone (TSH). TSH levels significantly impact a patient's resting energy expenditure, with hypothyroidism decreasing and hyperthyroidism increasing energy requirements. Clinical hypothyroidism has been correlated with increased ventilator dependency in patients with critical illness and malnutrition. The following case study describes the utilization of IC to trigger a full evaluation for the diagnosis of hypothyroidism in an adult patient with multiple myeloma who was mechanically ventilated. IC results for this patient were 39% lower than estimated by predictive energy equations. TSH, thyroxine, and triiodothyronine serum assays were obtained to rule out hypothyroidism. Based on elevated TSH and low thyroxine, the patient was found to have undiagnosed hypothyroidism. Appropriate pharmaceutical and nutrition interventions were made based upon these results. This case demonstrates the impact hormonal changes can have on resting energy expenditure and how the utilization of IC can provide additional information other than energy requirements.

UI	MeSH Term	Description	Entries
D007037	Hypothyroidism	A syndrome that results from abnormally low secretion of THYROID HORMONES from the THYROID GLAND, leading to a decrease in BASAL METABOLIC RATE. In its most severe form, there is accumulation of MUCOPOLYSACCHARIDES in the SKIN and EDEMA, known as MYXEDEMA. It may be primary or secondary due to other pituitary disease, or hypothalamic dysfunction.	Central Hypothyroidism,Primary Hypothyroidism,Secondary Hypothyroidism,TSH Deficiency,Thyroid-Stimulating Hormone Deficiency,Central Hypothyroidisms,Deficiency, TSH,Deficiency, Thyroid-Stimulating Hormone,Hormone Deficiency, Thyroid-Stimulating,Hypothyroidism, Central,Hypothyroidism, Primary,Hypothyroidism, Secondary,Hypothyroidisms,Primary Hypothyroidisms,Secondary Hypothyroidisms,TSH Deficiencies,Thyroid Stimulating Hormone Deficiency,Thyroid-Stimulating Hormone Deficiencies
D009751	Nutritional Requirements	The amounts of various substances in food needed by an organism to sustain healthy life.	Dietary Requirements,Nutrition Requirements,Dietary Requirement,Nutrition Requirement,Nutritional Requirement,Requirement, Dietary,Requirement, Nutrition,Requirement, Nutritional,Requirements, Dietary,Requirements, Nutrition,Requirements, Nutritional
D012121	Respiration, Artificial	Any method of artificial breathing that employs mechanical or non-mechanical means to force the air into and out of the lungs. Artificial respiration or ventilation is used in individuals who have stopped breathing or have RESPIRATORY INSUFFICIENCY to increase their intake of oxygen (O2) and excretion of carbon dioxide (CO2).	Ventilation, Mechanical,Mechanical Ventilation,Artificial Respiration,Artificial Respirations,Mechanical Ventilations,Respirations, Artificial,Ventilations, Mechanical
D002153	Calorimetry, Indirect	Calculation of the energy expenditure in the form of heat production of the whole body or individual organs based on respiratory gas exchange.	Calorimetry, Respiration,Calorimetries, Indirect,Calorimetries, Respiration,Indirect Calorimetries,Indirect Calorimetry,Respiration Calorimetries,Respiration Calorimetry
D004734	Energy Metabolism	The chemical reactions involved in the production and utilization of various forms of energy in cells.	Bioenergetics,Energy Expenditure,Bioenergetic,Energy Expenditures,Energy Metabolisms,Expenditure, Energy,Expenditures, Energy,Metabolism, Energy,Metabolisms, Energy
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000328	Adult	A person having attained full growth or maturity. Adults are of 19 through 44 years of age. For a person between 19 and 24 years of age, YOUNG ADULT is available.	Adults
D016638	Critical Illness	A disease or state in which death is possible or imminent.	Critically Ill,Critical Illnesses,Illness, Critical,Illnesses, Critical