PMID- 32636278
OWN - NLM
STAT- MEDLINE
DCOM- 20210208
LR  - 20230322
IS  - 1943-3654 (Electronic)
IS  - 0020-1324 (Linking)
VI  - 66
IP  - 2
DP  - 2021 Feb
TI  - End-Tidal-to-Arterial P(CO(2)) Ratio as Signifier for Physiologic Dead-Space 
      Ratio and Oxygenation Dysfunction in Acute Respiratory Distress Syndrome.
PG  - 263-268
LID - 10.4187/respcare.08061 [doi]
AB  - BACKGROUND: The ratio of end-tidal CO(2) pressure to arterial partial pressure of 
      CO(2) ([Formula: see text]) was recently suggested for monitoring pulmonary gas 
      exchange in patients with ARDS associated with COVID-19, yet no evidence was 
      offered supporting that claim. Therefore, we evaluated whether [Formula: see 
      text] might be relevant in assessing ARDS not associated with COVID-19. METHODS: 
      We evaluated the correspondence between [Formula: see text] and the ratio of dead 
      space to tidal volume (V(D)/V(T)) measured in 561 subjects with ARDS from a 
      previous study in whom [Formula: see text] data were also available. Subjects 
      also were analyzed according to 4 ranges of [Formula: see text] representing 
      increasing illness severity (>/= 0.80, 0.6-0.79, 0.50-0.59, and < 0.50). 
      Correlation was assessed by either Pearson or Spearman tests, grouped comparisons 
      were assessed using either ANOVA or Kruskal-Wallis tests and dichotomous 
      variables assessed by Fisher Exact tests. Normally distributed data are presented 
      as mean and standard deviation(SD) and non-normal data are presented as median 
      and inter-quartile range (IQR). Overall mortality risk was assessed with 
      multivariate logistic regression. Alpha was set at 0.05. RESULTS: [Formula: see 
      text] correlated strongly with V(D)/V(T) (r = -0.87 [95% CI -0.89 to -0.85], P < 
      .001). Decreasing [Formula: see text] was associated with increased V(D)/V(T) and 
      hospital mortality between all groups. In the univariate analysis, for every 0.01 
      decrease in [Formula: see text], mortality risk increased by  approximately 1% (odds ratio 
      0.009, 95% CI 0.003-0.029, P < .001) and maintained a strong independent 
      association with mortality risk when adjusted for other variables (odds ratio 
      0.19, 95% CI 0.04-0.91, P = .039). [Formula: see text] < 0.50 was characterized 
      by very high mean +/- SD value for V(D)/V(T) (0.82 +/- 0.05, P < .001) and high 
      hospital mortality (70%). CONCLUSIONS: Using [Formula: see text] as a surrogate 
      for V(D)/V(T) may be a useful and practical measurement for both management and 
      ongoing research into the nature of ARDS.
CI  - Copyright (c) 2021 by Daedalus Enterprises.
FAU - Kallet, Richard H
AU  - Kallet RH
AD  - Department of Anesthesia and Perioperative Care, Respiratory Care Division, 
      University of California, San Francisco at San Francisco General Hospital, San 
      Francisco, California. richkallet@gmail.com.
FAU - Lipnick, Michael S
AU  - Lipnick MS
AD  - Department of Anesthesia and Perioperative Care, Critical Care Division, 
      University of California, San Francisco at San Francisco General Hospital, San 
      Francisco, California.
LA  - eng
PT  - Journal Article
DEP - 20200707
PL  - United States
TA  - Respir Care
JT  - Respiratory care
JID - 7510357
RN  - 142M471B3J (Carbon Dioxide)
SB  - IM
MH  - Arterial Pressure
MH  - COVID-19
MH  - Carbon Dioxide/*blood
MH  - Humans
MH  - Partial Pressure
MH  - *Respiratory Dead Space
MH  - Respiratory Distress Syndrome/diagnosis/*physiopathology
MH  - Tidal Volume
OTO - NOTNLM
OT  - ARDS
OT  - end-tidal carbon dioxide pressure
OT  - ratio of arterial-to-alveolar oxygen tension
OT  - ratio of dead space to tidal volume
COIS- Mr Kallet has disclosed a relationship with Nihon Kohden. Dr Lipnick has 
      disclosed no conflicts of interest.
EDAT- 2020/07/09 06:00
MHDA- 2021/02/09 06:00
CRDT- 2020/07/09 06:00
PHST- 2020/07/09 06:00 [pubmed]
PHST- 2021/02/09 06:00 [medline]
PHST- 2020/07/09 06:00 [entrez]
AID - respcare.08061 [pii]
AID - 10.4187/respcare.08061 [doi]
PST - ppublish
SO  - Respir Care. 2021 Feb;66(2):263-268. doi: 10.4187/respcare.08061. Epub 2020 Jul 
      7.