by Suárez-Sipmann, Fernando, Santos, Arnoldo, Bohm, Stephan H, Borges, Joao Batista, Hedenstierna, Göran and Tusman, Gerardo
Abstract:
Dead space ratio is determined using Enghoff’s modification (VD(B-E)/VT) of Bohr’s formula (VD(Bohr)/VT) in which arterial is used as a surrogate of alveolar PCO₂. In presence of intrapulmonary shunt Enghoff’s approach overestimates dead space. In 40 lung-lavaged pigs we evaluated the Kuwabara’s and Niklason’s algorithms to correct for shunt effects and hypothesized that corrected VD(B-E)/VT should provide similar values as VD(Bohr)/VT. We analyzed 396 volumetric capnograms and arterial and mixed-venous blood samples to calculate VD(Bohr)/VT and VD(B-E)/VT. Thereafter, we corrected the latter for shunt effects using Kuwabara’s (K) VD(B-E)/VT and Niklason’s (N) VD(B-E)/VT algorithms. Uncorrected VD(B-E)/VT (mean ± SD of 0.70 ± 0.10) overestimated VD(Bohr)/VT (0.59 ± 0.12) (p textless 0.05), over the entire range of shunts. Mean (K) VD(B-E)/VT was significantly higher than VD(Bohr)/VT (0.67 ± 0.08, bias -0.085, limits of agreement -0.232 to 0.085; p textless 0.05) whereas (N)VD(B-E)/VT showed a better correction for shunt effects (0.64 ± 0.09, bias 0.048, limits of agreement -0.168 to 0.072; p textless 0.05). Neither Kuwabara’s nor Niklason’s algorithms were able to correct Enghoff’s dead space formula for shunt effects.
Reference:
Corrections of Enghoff’s dead space formula for shunt effects still overestimate Bohr’s dead space. (Suárez-Sipmann, Fernando, Santos, Arnoldo, Bohm, Stephan H, Borges, Joao Batista, Hedenstierna, Göran and Tusman, Gerardo), In Respiratory physiology & neurobiology, volume 189, 2013.
Bibtex Entry:
@article{suarez-sipmann_corrections_2013,
	title = {Corrections of {Enghoff}'s dead space formula for shunt effects still overestimate {Bohr}'s dead space.},
	volume = {189},
	url = {http://linkinghub.elsevier.com/retrieve/pii/S1569904813002267},
	doi = {10.1016/j.resp.2013.06.020},
	abstract = {Dead space ratio is determined using Enghoff's modification (VD(B-E)/VT) of Bohr's formula (VD(Bohr)/VT) in which arterial is used as a surrogate of alveolar PCO₂. In presence of intrapulmonary shunt Enghoff's approach overestimates dead space. In 40 lung-lavaged pigs we evaluated the Kuwabara's and Niklason's algorithms to correct for shunt effects and hypothesized that corrected VD(B-E)/VT should provide similar values as VD(Bohr)/VT. We analyzed 396 volumetric capnograms and arterial and mixed-venous blood samples to calculate VD(Bohr)/VT and VD(B-E)/VT. Thereafter, we corrected the latter for shunt effects using Kuwabara's (K) VD(B-E)/VT and Niklason's (N) VD(B-E)/VT algorithms. Uncorrected VD(B-E)/VT (mean ± SD of 0.70 ± 0.10) overestimated VD(Bohr)/VT (0.59 ± 0.12) (p {textless} 0.05), over the entire range of shunts. Mean (K) VD(B-E)/VT was significantly higher than VD(Bohr)/VT (0.67 ± 0.08, bias -0.085, limits of agreement -0.232 to 0.085; p {textless} 0.05) whereas (N)VD(B-E)/VT showed a better correction for shunt effects (0.64 ± 0.09, bias 0.048, limits of agreement -0.168 to 0.072; p {textless} 0.05). Neither Kuwabara's nor Niklason's algorithms were able to correct Enghoff's dead space formula for shunt effects.},
	language = {English},
	number = {1},
	journal = {Respiratory physiology & neurobiology},
	author = {Suárez-Sipmann, Fernando and Santos, Arnoldo and Bohm, Stephan H and Borges, Joao Batista and Hedenstierna, Göran and Tusman, Gerardo},
	month = oct,
	year = {2013},
	pmid = {23827851},
	pages = {99--105}
}