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Background Dynamic indices, including pulse pressure, systolic pressure, and stroke volume variation (PPV, SPV, and SVV), are accurate predictors of fluid responsiveness under strict conditions, for example, controlled mechanical ventilation using conventional tidal volumes (TVs) in the absence of cardiac arrhythmias. However, in routine clinical practice, these prerequisites are not always met. We evaluated the effect of regularly used ventilator settings, different calculation methods, and the presence of cardiac arrhythmias on the ability of dynamic indices to predict fluid responsiveness in sedated, mechanically ventilated patients. Methods We prospectively evaluated 47 fluid challenges in 29 consecutive cardiac surgery patients. Patients were divided into different groups based on TV. Dynamic indices were calculated in various ways: calculation over 30 s, breath-by-breath (with and without excluding arrhythmias), and with correction for TV. Results The predictive value was optimal in the group ventilated with TVs >7 ml kg−1 with correction for TV, calculated breath-by-breath, and with exclusion of arrhythmias [area under the curve (AUC)=0.95, 0.93, and 0.90 for PPV, SPV, and SVV, respectively]. Including patients ventilated with lower TVs decreased the predictive value of all dynamic indices, while calculating dynamic indices over 30 s and not excluding cardiac arrhythmias further reduced the AUC to 0.51, 0.63, and 0.51 for PPV, SPV, and SVV, respectively. Conclusions PPV, SPV, and SVV are the only reliable predictors of fluid responsiveness under strict conditions. In routine clinical practice, factors including low TV, cardiac arrhythmias, and the calculation method can substantially reduce their predictive value. [ABSTRACT FROM PUBLISHER]

Background: Continuous non-invasive measurement of finger arterial pressure (FAP) is a reliable technology in adults. FAP is measured with an inflatable cuff around the finger and simultaneously converted to a reconstructed brachial artery pressure waveform (reBAP) by the Nexfin™ device. We assessed the adequacy of a prototype device (Nexfin-paediatric), designed for a paediatric population, for detecting rapid arterial pressure changes in children during cardiac surgery. [ABSTRACT FROM PUBLISHER]

Background Asthma is a common disease in children and often develops early in life. This multicentre retrospective case series describe the use and effectiveness of sevoflurane inhalation therapy in a series of children with severe asthma in the paediatric intensive care unit (PICU). Methods Seven children ranging from 4 to 13 yr of age admitted to the PICU of two tertiary care hospitals in the Netherlands were included. They all were admitted with the diag-nosis of severe asthma requiring invasive mechanical ventilation and were treated with sevoflurane inhalation therapy. Results The median (range) Pco2 level at the start, after 2 h, and at the end of sevoflurane treatment were 14 (5.1–24.8), 9.8 (5.4–17.0), and 6.2 (4.5–11.4) kPa (P=0.05) while the median (range) pH was 7.02 (6.97–7.36), 7.18 (7.04–7.35), and 7.43 (7.15–7.47) kPa (P=0.01), respectively. The median (range) peak pressure values declined from 30 (23–56) to 20.4 (14–33) cm H2O (P=0.03). No severe adverse effects besides hypotension, with sufficient response to norepinephrine treatment, were seen. Conclusions Sevoflurane inhalation corrects high levels of Pco2 and provides clinical improvement in mechanically ventilated children with life-threatening asthma who fail to respond to conventional treatment. [ABSTRACT FROM PUBLISHER]

Background The transpulmonary thermodilution (TPTD) technique is widely used in clinical practice for measuring cardiac output (CO). This study was designed to investigate the influence of various levels of pulmonary oedema on the reliability of CO measurements by the TPTD method. Methods In 11 newborn lambs pulmonary oedema was induced using a surfactant washout technique. Serial CO measurements using TPTD (COTPTD) were performed at various amounts of lung water. Simultaneously, CO was measured by an ultrasound flow probe around the main pulmonary artery (COMPA) and used as the standard reference. CO was divided by the body surface area to calculate cardiac index (CI). Data were analysed using correlational statistics and Bland–Altman analysis. Results One lamb died prematurely. A total of 56 measurements in 10 lambs were analysed with a median CIMPA of 2.95 (IQR 1.04) litre min−1 m−2. Mean percentage increase in extravascular lung water (EVLW) between the start and the end of the study was 126.4% (sd 40.4). Comparison of the two CO methods showed a mean bias CI of −0.16 litre min−1 m−2 (limits of agreement ±0.73 litre min−1 m−2) and a percentage error of 23.8%. Intraclass correlation coefficients were 0.91 (95% CI 0.81–0.95) for absolute agreement and 0.92 (95% CI 0.87–0.95) for consistency. Acceptable agreement was confirmed by a tolerability-agreement ratio of 0.39. The within-subject correlation between the amount of EVLWI and the bias between the two methods was not significant (−0.02; P=0.91). Conclusions CO measurements by the transpulmonary thermodilution technique over a wide range of CI values are not affected by the presence of high EVLWI. The slight underestimation of the CO is independent of the amount of pulmonary oedema. [ABSTRACT FROM AUTHOR]

Background Pulse pressure variation (PPV) and systolic pressure variation (SPV) are reliable predictors of fluid responsiveness in patients undergoing controlled mechanical ventilation. Currently, PPV and SPV are measured invasively and it is unknown if an arterial pressure (AP) signal obtained with a finger cuff can be used as an alternative. The aim of this study was to validate PPV and SPV measured using a finger cuff. Methods Patients receiving mechanical ventilation under sedation after cardiac artery bypass graft (CABG) surgery were included after arrival on the intensive care unit. AP was measured invasively in the radial artery and non-invasively using the finger cuff of the Nexfin™ monitor. I.V. fluid challenges were administered according to clinical need. The mean value of PPV and SVV was calculated before and after administration of a fluid challenge. Agreement of the calculated PPV and SPV from both methods was assessed using the Bland–Altman analysis. Results Nineteen patients were included and 28 volume challenges were analysed. Correlation between the two methods for PPV and SPV [mean (sd)=6.9 (4.3)% and 5.3 (2.6)%, respectively] was r=0.96 (P<0.0001) and r=0.95 (P<0.0001), respectively. The mean bias was −0.95% for PPV and −0.22% for SPV. Limits of agreement were −4.3% and 2.4% for PPV and −2.2% and 1.7% for SPV. The correlation between changes in PPV and SPV as a result of volume expansion measured by the two different methods was r=0.88 (P<0.0001) and r=0.87 (P<0.0001), respectively. Conclusions In patients receiving controlled mechanical ventilation after CABG, PPV and SPV can be measured reliably non-invasively using the inflatable finger cuff of the Nexfin™ monitor. [ABSTRACT FROM PUBLISHER]

Background The transpulmonary thermodilution (TPTD) technique for measuring cardiac output (CO) has never been validated in the presence of a left-to-right shunt. Methods In this experimental, paediatric animal model, nine lambs with a surgically constructed aorta-pulmonary left-to-right shunt were studied under various haemodynamic conditions. CO was measured with closed and open shunt using the TPTD technique (COTPTD) with central venous injections of ice-cold saline. An ultrasound transit time perivascular flow probe around the main pulmonary artery served as the standard reference measurement (COMPA). Results Seven lambs were eligible for further analysis. Mean (sd) weight was 6.6 (1.6) kg. The mean COMPA was 1.21 litre min–1 (range 0.61–2.06 l min–1) with closed shunt and 0.93 litre min−1 (range 0.48–1.45 litre min−1) with open shunt. The open shunt resulted in a mean Qp/Qs ratio of 1.8 (range 1.6–2.4). The bias between the two CO methods was 0.17 litre min−1 [limits of agreement (LOA) of 0.27 litre min−1] with closed shunt and 0.14 litre min–1 (LOA of 0.32 litre min−1) with open shunt. The percentage errors were 22% with closed shunt and 34% with open shunt. The correlation (r) between the two methods was 0.93 (P<0.001) with closed shunt and 0.86 (P<0.001) with open shunt. The correlation (r) between the two methods in tracking changes in CO (ΔCO) during the whole experiment was 0.94 (P<0.0001). Conclusions The TPTD technique is a feasible method of measuring CO in paediatric animals with a left-to-right shunt. [ABSTRACT FROM AUTHOR]