Inferior vena cava collapsibility index versus passive leg raise for the assessment of fluid responsiveness in non-intubated spontaneously breathing septic patients
Date of Award
Master of Medicine (MMed)
Prof. Wangari Waweru-Siika
Dr. Jeilan Mohamed
Dr. Idris Chikophe
Anaesthesiology (East Africa)
Background: Sepsis can cause deleterious organ deterioration due to deranged patient’s response to infection. Rapid fluid loading at diagnosis is part of standard treatment. While inadequate fluid administration may lead to tissue hypoperfusion and organ failure, excessive fluid administration may cause fluid overload and pulmonary oedema. Predictive tools of fluid responsiveness are therefore required to guide fluid resuscitation. The Passive Leg Raise (PLR) manoeuvre can predict fluid responsiveness in non-intubated patients with sepsis-induced hypotension but is challenging to perform in clinical practice. The Inferior Vena Cava Collapsibility Index (IVCCI) on the other hand is a non-invasive test that can be used to predict fluid responsiveness in non-intubated patients but is not routinely performed at the Aga Khan University Hospital Nairobi.
Aim: To investigate the correlation between Inferior Vena Cava Collapsibility Index (IVCCI) and a Passive Leg Raise (PLR) manoeuvre for the assessment of fluid responsiveness in non-intubated spontaneously breathing sepsis patients at the Aga Khan University Hospital Nairobi.
Methodology: A prospective observational study which recruited non-intubated spontaneously breathing septic patients who were hypotensive (mean arterial pressure less than 65 mm Hg), requiring fluid resuscitation. Focused Cardiac Ultrasound (FoCUS) was used to measure IVCCI followed immediately by a PLR manoeuvre for comparison. Patients were classified as fluid responders if they had an IVCCI ≥ 50% (maximum diameter- minimum diameter/maximum diameter x 100) and/or an increase of 10% in pulse pressure following a PLR. The correlation between IVCCI and PLR on each patient in predicting fluid responsiveness was then assessed.
Data analysis: The primary outcome was binary in nature (responder versus non-responder) generated from IVCCI and PLR manoeuvre measurements from the same patient. The correlation between these outcomes was tested using McNemar’s test to compare paired proportions and quantify the level of agreement between the two using Kappa statistics. P < 0.05 was considered statistically significant. An IVCCI cut-off of 30% would have resulted in a near- perfect agreement as evidenced by a Cohen’s Kappa value of 0.93. A cut off between 30-40% would give a Cohen’ Kappa of 0.81 with a strong level of agreement.
Results: 38 patients satisfied the inclusion criteria. McNemar’s test yielded a p=0.039 indicating that PLR test and IVCCI are not equivalent in predicting fluid responsiveness in non-intubated septic patients at AKUHN. A Cohen’s Kappa of 0.283 signified only “fair” correlation between the two.
Conclusion: The PLR test and IVCCI test have a fair correlation and are not identical in predicting fluid responsiveness in non-intubated spontaneously breathing septic patients in AKUHN. The influence of breathing pattern on IVCCI and our chosen threshold may have influenced our results. Further studies on this topic may explore lower cut-off values of the IVCCI to predict fluid responsiveness, as the measurements used in prior studies are not defined in the Kenyan population.
Githaiga, A. (2021). Inferior vena cava collapsibility index versus passive leg raise for the assessment of fluid responsiveness in non-intubated spontaneously breathing septic patients (Unpublished master's dissertation). Aga Khan University, East Africa.