Inferior vena cava collapsibility index versus passive leg raise to assess fluid responsiveness in non-intubated septic patients a prospective observational study

Background: Rapid fluid loading at diagnosis of sepsis is part of standard treatment. Predictive tools of fluid responsiveness are required to guide fluid resuscitation. The Passive Leg Raise [PLR] manoeuvre can predict fluid responsiveness in non-intubated patients with sepsis. The Inferior Vena Cava Collapsibility Index [IVCCI] can also be utilised but is not routinely performed. 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 septic patients in a tertiary referral hospital in Sub-Saharan Africa. Methodology: A prospective observational study which recruited non-intubated 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% 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. 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. A Cohen’s Kappa of 0.283 signified only a “fair” correlation between the two. 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. 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