Key result
A high carbon monoxide bolus (1.4 ml/kg) resulted in significantly lower total haemoglobin mass measurements (776 g) compared to low (791 g) or medium (788 g) boluses.
Why the study?
Does the size of the carbon monoxide bolus influence the measurement of total haemoglobin mass using the optimized CO-rebreathing method?
Does the size of the carbon monoxide bolus influence the measurement of total haemoglobin mass using the optimized CO-rebreathing method?
Absolute Event Rate: 776% vs 791%
A CO bolus of 1.0 ml/kg provides adequate precision and acceptable safety for measuring total haemoglobin mass using the optimized CO-rebreathing method, whereas higher doses may slightly underestimate the mass.
Supports 1.0 ml/kg CO bolus to avoid tHb underestimation; leaves optimal dosing open for further validation.
The optimized carbon monoxide (CO) rebreathing method (oCOR-method) is routinely used to measure total haemoglobin mass (tHbmass). The tHbmass measure is subject to a test-retest typical error of ~2%, mostly from the precision of carboxyhaemoglobin (HbCO) measurement. We hypothesized that tHbmass would be robust to differences in the bolus of CO administered during the oCOR-method. Twelve participants (ten males and two females; age 27 ± 6 yr, height 177 ± 11 cm and mass 73.9 ± 12.1 kg) completed the oCOR-method on four occasions. Different bolus of CO were administered (LOW: 0.6 ml kg(-1); MED1: 1.0 ml kg(-1) and HIGH: 1.4 ml kg(-1)); to determine the reliability of MED1, a second trial was conducted (MED2). tHbmass was found to be significantly less from the HIGH CO bolus (776 ± 148 g) when compared to the LOW CO (791 ± 149 g) or MED1 CO (788 ± 149 g) trials. MED2 CO was 785 ± 150 g. The measurement of tHbmass is repeatable to within 0.8%, but a small and notable difference was seen when using a HIGH CO bolus (1.4 to 1.9% less), potentially due to differences in CO uptake kinetics. Previously, an improved precision of the oCOR-method was thought to require a higher bolus of CO (i.e. larger Δ%HbCO), as commercial hemoximeters only estimate %HbCO levels to a single decimal place (usually ± 0.1%). With the new hemoximeter used in this study, a bolus of 1.0 ml kg(-1) allows adequate precision with acceptable safety.
No takes yet. Share an insight, caveat, or question.
Turner et al. (2014) studied this question. Carbon monoxide (CO) bolus vs. Different doses compared to each other was evaluated on Total haemoglobin mass (tHbmass). A high carbon monoxide bolus (1.4 ml/kg) resulted in significantly lower total haemoglobin mass measurements (776 g) compared to low (791 g) or medium (788 g) boluses.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: