IntroductionThe Nexfin device estimates arterial pressure by the volume clamp method through a finger pneumatic cuff. It also allows to estimate cardiac index (CInoninv) by pulse contour analysis of the non-invasive arterial pressure curve. We evaluated the ability of the device to track changes in cardiac index induced by a fluid challenge.MethodsWe included 45 patients for whom a volume expansion (500 mL of saline infused over 30 min) was planned. The volume expansion-induced changes in cardiac index measured by transpulmonary thermodilution (CIinv, PiCCO device) and in CInoninv were recorded.ResultsIn seven patients, the Nexfin could not record the arterial curve due to finger hypoperfusion. Considering both the values obtained before and after volume expansion (n = 76 pairs of measurements), the bias (lower and upper limits of agreement) between CIinv and CInoninv was 0.2 (-1.8 to 2.2) L/min/m2. The mean change in CInoninv was 10 ± 11%. The percentage error of CInoninv was 57%. The correlation between the changes in CIinv and CInoninv observed during volume expansion was significant (P = 0.0002) with an r2 = 0.31.ConclusionsThe estimation of CI by the Nexfin device in critically ill patients is not reliable, neither for estimating absolute values of CI nor for tracking its changes during volume expansion.

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(Can J Anesth/J Can Anesth. 2019;66:762–771) Neuraxial anesthesia is preferable for cesarean deliveries (CDs), as it allows mothers to be awake and avoids the associated risks of general anesthesia. However, an estimated 53% of patients under neuraxial anesthesia suffer from shivering. Uncontrolled shivering intervenes with vital sign monitoring, causes physiological stress, and affects a patient’s satisfaction and comfort. The most common pharmacological treatment for shivering is meperidine (a synthetic opioid). However, as this drug becomes increasingly scarce in North American hospitals, an effective alternative agent is desired. Dexmedetomidine is an alternative treatment for shivering and can alleviate shivering while avoiding side effects associated with opioids. The aim of this study was to test whether a single bolus of 30 μg intravenous (IV) dexmedetomidine, administered 5 minutes after childbirth, could reduce shivering during CD under neuraxial anesthesia.

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