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Editorials: Point and Counterpoint |

Rebuttal From Dr Kory FREE TO VIEW

Pierre Kory, MD
Author and Funding Information

FINANCIAL/NONFINANCIAL DISCLOSURE: The author has reported to CHEST the following: P. K. received a stipend from SonoSite/Fujifilm to provide a video-based tutorial based on how to diagnose a DVT using ultrasound.

Trauma and Life Support Center, Critical Care Service, University of Wisconsin School of Medicine and Public Health, Madison, WI

CORRESPONDENCE TO: Pierre Kory, MD, Trauma and Life Support Center, Critical Care Service, University of Wisconsin School of Medicine and Public Health, 600 Highland Ave, Centennial Bldg, Room 5245, Madison, WI 53792


Copyright 2016, American College of Chest Physicians. All Rights Reserved.


Chest. 2017;151(3):537-538. doi:10.1016/j.chest.2016.11.020
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Published online

I appreciate and commend Dr Schmidt’s succinct review of the physiology underlying cardiac filling and output. He accurately observes that IVC distention has a strong correlation with FR. He neglects to mention, however, that IVC distention is found in such rare circumstances, it could never serve as the primary guide to fluid resuscitation unless we heavily sedated, paralyzed, and overinflated our intubated patients, an approach violating some of the most beneficial patient care practices we know of today (ie, low-tidal volume ventilation, avoiding delirium, increasing mobility). Thus, the debate rests almost entirely on the predictive merits of the most common respirophasic IVC variation encountered, which is IVC collapse.

Several of Dr Schmidt’s physiologic observations on IVC collapse were identical to those I cited in arguing against its utility to guide fluid resuscitation: (1) that IVC collapse results from spontaneous respiratory effort; and (2) that the magnitude of IVC collapse is almost entirely conditioned by the magnitude of respiratory effort and the level of right atrial pressure. This scenario is precisely the crux of my argument: the amount of IVC collapse (which Dr Schmidt provided instruction in measuring) provides no guidance to answering fluid needs given that: (1) the depth of respiratory effort is a physiologic parameter clearly independent of fluid status; and (2) “right-sided” pressures have been proven to have little utility in predicting FR. I again want to emphasize that the erroneous equating of low right atrial pressure (ie, small IVC) with hypovolemia will persist unless we understand that low right atrial pressure in patients with shock most commonly results from vasoplegia and hypercontractile heart function, two physiologic processes that only incompletely respond to fluid. The frequent “incomplete responses” encountered in low right atrial pressure is precisely why a better guide to fluid decisions is needed.

The aforementioned physiology strongly brings into question Dr Schmidt’s statement that “ΔIVC during spontaneous breathing predicts FR (diagnostic OR, 13.2).” To be fair, Dr Schmidt admits that this predictive ability is less than in passively ventilated patients and that spontaneously breathing patients is ΔIVC’s weakest link. Given the conflicting nature of these statements, a more specific analysis of the cited evidence is warranted.

The OR for FR of 13.2 was taken from a study published in 2014 by Zhang et al. Unfortunately, this “meta-analysis” contains too many limitations to be useful: (1) only a single study of IVC collapse in spontaneously breathing patients was used to calculate the OR (the study by Muller et al, in which 40% of patients were in shock from clinically overt hypovolemic insults); (2) one “negative” study of IVC collapse by Brun et al was excluded after being mischaracterized as not having studied spontaneously breathing patients; (3) another “negative” study by Corl et al was excluded due to incomplete data for meta-analysis; and (4) it was published prior to publication of three more of the largest “negative” studies on IVC collapse.,, The more current summary from Table 1 in my Counterpoint far better demonstrates its actual poor predictability.

In summary, based on the near complete lack of supportive physiology, experimental evidence, or clinical data demonstrating the ability of IVC collapse to reliably predict fluid needs in the critically ill, IVC ultrasound should not serve as the primary guide to fluid resuscitation.

References

Schmidt G.A. . Point: should acute fluid resuscitation be guided primarily by inferior vena cava ultrasound for patients in shock? Yes. Chest. 2017;151:531-532 [PubMed]journal
 
Mahjoub Y. .Lejeune V. .Muller L. .et al Evaluation of pulse pressure variation validity criteria in critically ill patients: a prospective observational multicentre point-prevalence study. Br J Anaesthesia. 2014;112:681-685 [PubMed]journal. [CrossRef]
 
Zhang Z. .Xu X. .Ye S. .Xu L. . Ultrasonographic measurement of the respiratory variation in the inferior vena cava diameter is predictive of fluid responsiveness in critically ill patients: systematic review and meta-analysis. Ultrasound Med Biol. 2014;40:845-853 [PubMed]journal. [CrossRef] [PubMed]
 
Muller L. .Bobbia X. .Toumi M. .et al Respiratory variations of inferior vena cava diameter to predict fluid responsiveness in spontaneously breathing patients with acute circulatory failure: need for a cautious use. Crit Care. 2012;16:R188- [PubMed]journal. [CrossRef] [PubMed]
 
Brun C. .Zieleskiewicz L. .Textoris J. .et al Prediction of fluid responsiveness in severe pre-eclamptic patients with oliguria. Intensive Care Med. 2013;39:593-600 [PubMed]journal. [CrossRef] [PubMed]
 
Corl K. .Napoli A.M. .Gardiner F. . Bedside sonographic measurement of the inferior vena cava caval index is a poor predictor of fluid responsiveness in emergency department patients. Emergency Medicine Australasia. 2012;24:534-539 [PubMed]journal. [CrossRef] [PubMed]
 
Airapetian A. .Maizel J. .Alyamani O. .et al Does inferior vena cava respiratory variability predict fluid responsiveness in critically ill patients? Crit Care. 2015;19:400- [PubMed]journal. [CrossRef] [PubMed]
 
De Valk S. .Olgers T.J. .Holman M. .et al The caval index: an adequate non-invasive ultrasound parameter to predict fluid responsiveness in the emergency department? BMC Anesthesiol. 2014;14:114- [PubMed]journal. [CrossRef] [PubMed]
 
Sobczyk D. .Nycz K. .Andruszki P. .et al Ultrasonographic caval indices do not significantly contribute to predicting fluid responsiveness immediately after coronary artery bypass grafting when compared to passive leg raising. Cardiovascular Ultrasound. 2016;14:23-29 [PubMed]journal. [PubMed]
 
Kory P. . Counterpoint: should acute fluid resuscitation be guided primarily by inferior vena cava ultrasound for patients in shock? No. Chest. 2017;151:533-536 [PubMed]journal
 

Figures

Tables

References

Schmidt G.A. . Point: should acute fluid resuscitation be guided primarily by inferior vena cava ultrasound for patients in shock? Yes. Chest. 2017;151:531-532 [PubMed]journal
 
Mahjoub Y. .Lejeune V. .Muller L. .et al Evaluation of pulse pressure variation validity criteria in critically ill patients: a prospective observational multicentre point-prevalence study. Br J Anaesthesia. 2014;112:681-685 [PubMed]journal. [CrossRef]
 
Zhang Z. .Xu X. .Ye S. .Xu L. . Ultrasonographic measurement of the respiratory variation in the inferior vena cava diameter is predictive of fluid responsiveness in critically ill patients: systematic review and meta-analysis. Ultrasound Med Biol. 2014;40:845-853 [PubMed]journal. [CrossRef] [PubMed]
 
Muller L. .Bobbia X. .Toumi M. .et al Respiratory variations of inferior vena cava diameter to predict fluid responsiveness in spontaneously breathing patients with acute circulatory failure: need for a cautious use. Crit Care. 2012;16:R188- [PubMed]journal. [CrossRef] [PubMed]
 
Brun C. .Zieleskiewicz L. .Textoris J. .et al Prediction of fluid responsiveness in severe pre-eclamptic patients with oliguria. Intensive Care Med. 2013;39:593-600 [PubMed]journal. [CrossRef] [PubMed]
 
Corl K. .Napoli A.M. .Gardiner F. . Bedside sonographic measurement of the inferior vena cava caval index is a poor predictor of fluid responsiveness in emergency department patients. Emergency Medicine Australasia. 2012;24:534-539 [PubMed]journal. [CrossRef] [PubMed]
 
Airapetian A. .Maizel J. .Alyamani O. .et al Does inferior vena cava respiratory variability predict fluid responsiveness in critically ill patients? Crit Care. 2015;19:400- [PubMed]journal. [CrossRef] [PubMed]
 
De Valk S. .Olgers T.J. .Holman M. .et al The caval index: an adequate non-invasive ultrasound parameter to predict fluid responsiveness in the emergency department? BMC Anesthesiol. 2014;14:114- [PubMed]journal. [CrossRef] [PubMed]
 
Sobczyk D. .Nycz K. .Andruszki P. .et al Ultrasonographic caval indices do not significantly contribute to predicting fluid responsiveness immediately after coronary artery bypass grafting when compared to passive leg raising. Cardiovascular Ultrasound. 2016;14:23-29 [PubMed]journal. [PubMed]
 
Kory P. . Counterpoint: should acute fluid resuscitation be guided primarily by inferior vena cava ultrasound for patients in shock? No. Chest. 2017;151:533-536 [PubMed]journal
 
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