Hypercapnic Respiratory Failure in Obesity-Hypoventilation Syndrome: CO(2) Response and Acetazolamide Treatment Effects.
Summary of "Hypercapnic Respiratory Failure in Obesity-Hypoventilation Syndrome: CO(2) Response and Acetazolamide Treatment Effects."
OBJECTIVE:
In obesity-hypoventilation-syndrome patients mechanically ventilated for hypercapnic respiratory failure we investigated the relationship between CO(2) response, body mass index, and plasma bicarbonate concentration, and the effect of acetazolamide on bicarbonate concentration and CO(2) response.
METHODS:
CO(2) response tests and arterial blood gas analysis were performed in 25 patients ready for a spontaneous breathing test, and repeated in a subgroup of 8 patients after acetazolamide treatment. CO(2) response test was measured as (1) hypercapnic drive response (the ratio of the change in airway occlusion pressure 0.1 s after the start of inspiratory flow to the change in P(aCO(2))), and (2) hypercapnic ventilatory response (the ratio of the change in minute volume to the change in P(aCO(2))).
RESULTS:
We did not find a significant relationship between CO(2) response and body mass index. Patients with higher bicarbonate concentration had a more blunted CO(2) response. Grouping the patients according to the first, second, and third tertiles of the bicarbonate concentration, the hypercapnic drive response was 0.32 ± 0.17 cm H(2)O/mm Hg, 0.22 ± 0.15 cm H(2)O/mm Hg, and 0.10 ± 0.06 cm H(2)O/mm Hg, respectively (P = .01), and hypercapnic ventilatory response was 0.46 ± 0.23 L/min/mm Hg, 0.48 ± 0.36 L/min/mm Hg, and 0.22 ± 0.16 L/min/mm Hg, respectively (P = .04). After acetazolamide treatment, bicarbonate concentration was reduced by 8.4 ± 3.0 mmol/L (P = .01), and CO(2) response was shifted to the left, with an increase in hypercapnic drive response, by 0.14 ± 0.16 cm H(2)O/mm Hg (P = .02), and hypercapnic ventilatory response, by 0.11 ± 0.22 L/min/mm Hg (P = .33).
CONCLUSIONS:
Patients with obesity-hypoventilation syndrome and higher bicarbonate concentrations had a more blunted CO(2) response. Body mass index was not related to CO(2) response. Acetazolamide decreased bicarbonate concentration and increased CO(2) response.
Affiliation
Intensive Care Unit, Hospital Universitari Son Dureta, Andrea Doria 55, 07014, Palma de Mallorca, Illes Balears, Spain. joan.raurich@ssib.es.
Journal Details
This article was published in the following journal.
Name: Respiratory care
ISSN: 0020-1324
Pages: 1442-8
Links
- PubMed Source: http://www.ncbi.nlm.nih.gov/pubmed/20979670
- DOI: http://dx.doi.org/
Medical and Biotech [MESH] Definitions
Obesity Hypoventilation Syndrome
HYPOVENTILATION syndrome in very obese persons with excessive ADIPOSE TISSUE around the ABDOMEN and DIAPHRAGM. It is characterized by diminished to absent ventilatory chemoresponsiveness; chronic HYPOXIA; HYPERCAPNIA; POLYCYTHEMIA; and long periods of sleep during day and night (HYPERSOMNOLENCE). It is a condition often related to OBSTRUCTIVE SLEEP APNEA but can occur separately.
Hantavirus Pulmonary Syndrome
Acute respiratory illness in humans caused by the Muerto Canyon virus whose primary rodent reservoir is the deer mouse Peromyscus maniculatus. First identified in the southwestern United States, this syndrome is characterized most commonly by fever, myalgias, headache, cough, and rapid respiratory failure.
Obesity, Abdominal
A condition of having excess fat in the abdomen. Abdominal obesity is typically defined as waist circumferences of 40 inches or more in men and 35 inches or more in women. Abdominal obesity raises the risk of developing disorders, such as diabetes, hypertension and METABOLIC SYNDROME X.
Potassium Deficiency
A condition due to decreased dietary intake of potassium, as in starvation or failure to administer in intravenous solutions, or to gastrointestinal loss in diarrhea, chronic laxative abuse, vomiting, gastric suction, or bowel diversion. Severe potassium deficiency may produce muscular weakness and lead to paralysis and respiratory failure. Muscular malfunction may result in hypoventilation, paralytic ileus, hypotension, muscle twitches, tetany, and rhabomyolysis. Nephropathy from potassium deficit impairs the concentrating mechanism, producing polyuria and decreased maximal urinary concentrating ability with secondary polydipsia. (Merck Manual, 16th ed)
Pseudohypoparathyroidism
A hereditary condition clinically resembling HYPOPARATHYROIDISM, but caused by failure of response to rather than deficiency of parathyroid hormones. It is characterized by hypocalcemia and hyperphosphatemia, and is commonly associated with short stature, obesity, short metacarpals, and ectopic calcification. (Dorland, 27th ed)
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