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 textpm SD of 0.70 textpm 0.10) overestimated VD(Bohr)/VT (0.59 textpm 0.12) (p < 0.05), over the entire range of shunts. Mean (K) VD(B-E)/VT was significantly higher than VD(Bohr)/VT (0.67 textpm 0.08, bias -0.085, limits of agreement -0.232 to 0.085; p < 0.05) whereas (N)VD(B-E)/VT showed a better correction for shunt effects (0.64 textpm 0.09, bias 0.048, limits of agreement -0.168 to 0.072; p < 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{SuarezSipmann:2013hs,
author = {Su{'a}rez-Sipmann, Fernando and Santos, Arnoldo and Bohm, Stephan H and Borges, Joao Batista and Hedenstierna, G{"o}ran and Tusman, Gerardo},
title = {{Corrections of Enghoff's dead space formula for shunt effects still overestimate Bohr's dead space.}},
journal = {Respiratory physiology {&} neurobiology},
year = {2013},
volume = {189},
number = {1},
pages = {99--105},
month = oct,
affiliation = {Department of Surgical Sciences, Section of Anesthesiology {&} Critical Care, Uppsala University, Uppsala, Sweden; Instituto de Investigaci{'o}n Sanitaria, Fundaci{'o}n Jim{'e}nez D{'i}az, IIS-FJD, Madrid, Spain; CIBERES, Spain. Electronic address: fsuarez.sipmann@surgsci.uu.se.},
doi = {10.1016/j.resp.2013.06.020},
pmid = {23827851},
language = {English},
rating = {0},
date-added = {2018-03-16T13:01:02GMT},
date-modified = {2020-07-09T13:27:49GMT},
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 {textpm} SD of 0.70 {textpm} 0.10) overestimated VD(Bohr)/VT (0.59 {textpm} 0.12) (p < 0.05), over the entire range of shunts. Mean (K) VD(B-E)/VT was significantly higher than VD(Bohr)/VT (0.67 {textpm} 0.08, bias -0.085, limits of agreement -0.232 to 0.085; p < 0.05) whereas (N)VD(B-E)/VT showed a better correction for shunt effects (0.64 {textpm} 0.09, bias 0.048, limits of agreement -0.168 to 0.072; p < 0.05). Neither Kuwabara's nor Niklason's algorithms were able to correct Enghoff's dead space formula for shunt effects.},
url = {http://linkinghub.elsevier.com/retrieve/pii/S1569904813002267},
uri = {url{papers3://publication/doi/10.1016/j.resp.2013.06.020}}
}