Etablering av "CO rebreathing method" for å måle totalt blodvolum og hemoglobinmasse hos pasienter med KOLS, iskemisk sykdom og hjerteinfarkt
Method: 15 stable CAD patients was recruited to this cross sectional study (Age 62±8 years, Height 174±6 cm, Body weight 82±11 kg, Time since diagnosis 24±5 months). Fourteen patients successfully completed the 2 minutes CO-rebreathing test increasing the CO% bound to haemoglobin (COHb%) from 1.5 ± 0.4% to 5.9 ± 0.6%. Results: COHb% decreased from 5.9 ± 0.6% to 4.5 ± 0.4% after 2 hours of rest, and returned to baseline levels 24hr after the test (1.4±0.4%). Resting heart rate, stroke volume, cardiac output and ejection fraction was 63 ± 11 beats/min, 93.9 ± 16.5 ml/beats, 5.84 ± 0.99 liter, 48.5 ± 5.7 % respectively before the test. During and 10 minutes after the test the parameters was not significantly different from baseline. All patients remained in sinus rhythm during the test and the 2 hour observation period with no unexpected arrhythmias. Systolic and diastolic blood pressure was 142 ± 17 mmHg and 86 ± 8 mmHg before the test and gradually decreased during the two hour observation period to 131 ± 8 and 79 ± 11mmHg (p less than 0.05). Troponin-T levels remained within normal range 24 hours after the test. Mean hemoglobin mass (Hb-mass) was 838 ± 160 grams. Relative to body mass BV was 75.1 ± 11.4 ml/kg, EV was 30.4 ± 5.5 ml/kg, and Hb-mass was 10.4 ± 2.0 g/kg, in correspondence with reference values for normal untrained subjects.
Conclusion: The improved CO-rebreathing test does not affect cardiovascular function in stable CAD patients when COHB% is increased to 6%.
Metoden for å måle blodvolum ved hjelp av repusting av små mengder karbonmonoksid, ser ut til å påvirke stabile pasienter med koronar hjertesykdom på samme måte som friske unge mennesker og vil derfor kunne benyttes både klinisk og til forskningsformål hos denne pasientgruppen.