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Mini-fluid challenge predicts fluid responsiveness during spontaneous breathing under spinal anaesthesia: An
Pierre-Grégoire Guinot1, Eugenie Bernard, Fanny Defrancq
1From the Anaesthesiology and Critical Care Department, Amiens University Hospital, Place Victor Pauchet, Amiens, France.
Background:
The ability to predict fluid responsiveness in spontaneously breathing patients under spinal anaesthesia is desirable.
Objective:
The objective of this study was to test whether variations in stroke volume (SV) in response to a fixed mini-fluid challenge (ΔSV100) measured by thoracic impedance cardiography (ICG) can predict fluid responsiveness in spontaneously breathing patients under spinal anaesthesia.
Design:
A prospective observational study.
Setting:
Anaesthesiology department in a university hospital.
Participants:
Seventy-three patients monitored by ICG during surgery under spinal anaesthesia.
Interventions:
Patients received a 100 ml fluid challenge followed by volume expansion with 500 ml of crystalloid.
Main Outcomes Measures:
Haemodynamic variables and bioimpedance indices [blood pressure, SV, cardiac output (CO)] were measured before and after fluid challenge and before and after volume expansion. Responders were defined as those with >15% increase in SV after volume expansion.
Results:
SV increased by at least 15% in 27 (37%) of the 73 patients. ΔSV100 predicted fluid responsiveness with an area under the receiver operating characteristic (AUC) curve of 0.93 [95% confidence interval (95% CI) 0.8 to 0.97, P < 0.001]. The cut-off was 7% and a grey zone ranging between 3 and 8% was observed in up to 14% of patients. SV baseline was a poor predictor of fluid responsiveness [AUC of 0.69 (95% CI 0.57 to 0.79, P = 0.002)].
Conclusion:
ΔSV100 greater than 7% accurately predicted fluid responsiveness during surgery with a grey zone ranging between 3 and 8%.
