Collapsibility and Distensibility Indices of Critically Ill Patients

By Mustafa Emin Canakci

Affiliations

1. Department of Emergency Medicine, Eskisehir Osmangazi University, Eskisehir, Turkey

doi: 10.29271/jcpsp.2022.07.953

Sir,

I have read with great interest the recent article, “Inferior Vena Cava Collapsibility Index and Central Venous Pressure for Fluid Assessment in the Critically Ill Patient” by Dodhy AA.¹ This article is a well-designed cross-sectional study for the detection of the collapsibility index of inferior vena cava (IVC) in critically ill patients. Also, this topic is very important for the emergency departments and intensive care units (ICUs). The use of point-of-care ultrasound for the critically ill patients by emergency physicians and intensivists has become widespread.

In the study of Dodhy, the researcher evaluated the diameter and collapsibility index of IVC in 126 patients and compared and correlated it with central venous pressure (CVP) in both mechanically ventilated and spontaneous breathing groups. There are some points I would like to point out about the study. The collapsibility index is a volume indicator that has been used safely in patients with spontaneous breathing for several years.^2,3 Positive-pressure ventilation elevates the pleural and right atrial pressures. Also, the venous return to the heart reduces by increasing intrathoracic pressure during inspiration. The IVC diameter increases during inspiration and contracts during expiration in a mechanically ventilated patient, unlike in spontaneous breathing.⁴ Since the researcher evaluated only IVC diameter and collapsibility index, I think that the distensibility index should be added to the study. Since the majority of the patients were mechanically ventilated, the distensibility index might give a different correlation coefficient.

Nonetheless, I think it is a very important article about the point-of-care ultrasound performed in the ICU. I think that it should be recommended to use the distensibility index as a non-invasive method in mechanically ventilated patients due to physiological changes.

COMPETING INTEREST:
The author declared no competing interest.

AUTHOR’S CONTRIBUTION:
MEC: Conceptualisation, writing, original draft, review and editing.

REFERENCES

1. Dodhy AA. Inferior vena cava collapsibility ındex and central venous pressure for fluid assessment in the critically Ill patient. J Coll Physicians Surg Pak 2021; 31(11): 1273-7. doi: 10.29271/jcpsp.2021.11.1273.
2. Barbier C, Loubières Y, Schmit C, Hayon J, Ricôme J-L, Jardin F, et al. Respiratory changes in inferior vena cava diameter are helpful in predicting fluid responsiveness in ventilated septic patients. Intensive Care Med 2004; 30(9):1740-6. doi: 10.1007/s00134-004-2259-8.
3. Gui J, Yang Z, Ou B, Xu A, Yang F, Chen Q, et al. Is the collapsibility ındex of the ınferior vena cava an accurate predictor for the early detection of ıntravascular volume change? Shock 2018; 49(1):29-32. doi: 10.1097/SHK. 0000000000000932.
4. Tan HL, Wijeweera O, Onigkeit J. Inferior vena cava guided fluid resuscitation – fact or fiction? Trends Anaesthesia Critical Care 2015; 5(2):70-5.