Cardiac intensive care providers require a comprehensive understanding of cardiac output and oxygen delivery. The estimation of cardiac output in clinical practice often relies on thermodilution and the Fick principle. Central venous saturation and lactate levels are commonly used indicators for cardiac output assessment. However, the relationship between venous lactate levels and venous oxygen saturation in paediatric cardiac intensive care patients remains unclear.

This is a single-centre retrospective pilot study aimed to investigate the correlation between venous lactate and venous oxygen saturation in paediatric patients. Data collected included venous saturation, heart rate, mean arterial blood pressure, arterial saturation by pulse oximetry, cerebral and renal near-infra-red spectroscopy values, and the presence of a functionally univentricular heart. Statistical analyses included Bayesian Pearson correlation and regression analyses.

A total of 203 data points from 37 unique patients were included in the analysis. There was no significant correlation between serum lactate and venous saturation (correlation coefficient = –0.01; Bayes factor 10 = 0.06). Serum lactate also did not correlate with other haemodynamic metrics. Venous saturation showed correlations with arterial saturation and cerebral and renal near-infra-red spectroscopy. Regression analysis revealed that parallel circulation, arterial saturation, and cerebral near-infra-red spectroscopy were predictive of venous saturation. The following equation resulted from the regression analysis: 68.0 – (12.7 x parallel circulation) – (0.8 x arterial saturation) + (0.3 x cerebral near-infra-red spectroscopy). This model had a Bayes factor 10 of 0.03 and adjusted R-squared was 0.29.

In paediatric cardiac intensive care patients, there is no significant correlation between venous lactate and venous saturation, suggesting that lactate may not be a reliable marker for assessing the adequacy of oxygen delivery in this population. Only a weak correlation could be identified once the venous saturation was 70% or lower. Additional research is needed to explore alternative markers for monitoring oxygen delivery in critically ill paediatric patients.

Monitoring venous saturation allows identification of inadequate systemic oxygen delivery. The aim was to develop a model using non-invasive haemodynamic variables to estimate the inferior caval vein saturation and to determine its prognostic utility.

This is a single-centre, retrospective study. A Bayesian Pearson’s correlation was conducted to model the inferior caval vein saturation. Next, a Bayesian linear regression was conducted for data from all the patients and from only those with parallel circulation. Venous saturation estimations were developed. The correlation of these estimates to the actual inferior caval vein saturation was assessed. The resulting models were then applied to two validation cohorts: biventricular circulation (arterial switch operation) and parallel circulation (Norwood operation).

One hundred and thirteen datasets were collected across 15 patients. Of which, 65% had parallel circulation. In all patients, the measured and estimated inferior caval vein saturations had a moderate and significant correlation with a coefficient of 0.64. In patients with parallel circulation, the measured and estimated inferior caval vein saturation had a moderate and significant correlation with a coefficient of 0.61. In the biventricular circulation cohort, the estimated inferior caval vein saturation had an area under the curve of 0.71 with an optimal cut-off of 49. In the parallel circulation cohort, the estimated interior caval vein saturation had an area under the curve of 0.83 with an optimal cut-off of 24%.

The inferior caval vein saturation can be estimated utilising non-invasive haemodynamic data. This estimate has correlation with measured inferior caval vein saturations and offers prognostic utility.

The use of a long backboard and cervical collar are commonly recommended by international guidelines for spinal immobilization, but both devices may cause several side effects. In a recent study, it was reported that spinal immobilization at 20° eliminated the decrease in pulmonary function secondary to spinal immobilization performed at 0°. Spinal immobilization at 20° is a new recommendation, but other potential effects need to be explored before it can be implemented in clinical use.

Hemodynamic observation is important in the management of trauma patients. The aim of this study was to investigate the effect of spinal immobilization at a 20° position instead of 0° on hemodynamic parameters.

This study included 53 healthy volunteers who underwent spinal immobilization in the supine position (00) and in an elevated position (200). Systolic arterial pressure (SAP), diastolic arterial pressure (DAP), mean arterial pressure (MAP), heart rate (HR), left ventricular outflow tract velocity time integral (LVOT-VTI), left ventricular stroke volume (LVSV), cardiac output (CO), inferior vena cava diameter inspiration (IVC diameter insp), IVC diameter expiration (IVC diameter exp), and inferior vena cava collapsibility index (IVC-CI) were measured at the 0th and 30th minutes of spinal immobilization in both positions. The data were compared for demonstrating the efficiency of both positions in spinal immobilization.

A statistically significant difference was found in the parameters of the IVC diameter (exp), IVC diameter (insp), LVOT-VTI, LVSV, and CO through the measurements starting in the 0th minute of the transition from 0° to 20° (P <.001). Delta values (∆) of hemodynamic parameters (∆IVC diameter [exp], ∆IVC diameter [insp], ∆LVOT-VTI, ∆SV, ∆CO, ∆IVC-CI, ∆MAP, ∆SAP, ∆DAP, and ∆HR) were similar in spinal immobilization at 0° and 20°.

The findings obtained from this study illustrate that spinal immobilization at 20° does not cause clinically significant hemodynamic changes in healthy subjects compared to spinal immobilization at 0°.

There is a paucity of functional data on mid-to-late preterm infants between 30+0 and 34+6 weeks gestation. We aimed to characterise transitional cardiopulmonary and haemodynamic changes during the first 48 hours in asymptomatic mid-to-late preterm infants.

Forty-five healthy preterm newborns (mean ± standard deviation) gestation of 32.7 ± 1.2 weeks) underwent echocardiography on Days 1 and 2. Ventricular mechanics were assessed by speckle tracking-derived deformation, rotational mechanics, tissue Doppler imaging, and right ventricle-focused measures (tricuspid annular plane systolic excursion, fractional area change). Continuous haemodynamics were assessed using the NICOM™ system to obtain left ventricular output, stroke volume, heart rate, and total peripheral resistance by non-invasive cardiac output monitoring.

Right ventricular function increased (all measures p < 0.005) with mostly stable left ventricular performance between Day 1 and Day 2. NICOM-derived left ventricular output [mean 34%, 95% confidence interval 21–47%] and stroke volume [29%, 16–42%] increased with no change in heart rate [5%, −2 to 12%]. There was a rise in mean blood pressure [11%, 1–21%], but a decline in total peripheral resistance [−14%, −25 to −3%].

Left ventricular mechanics remained persevered in mid-to-late premature infants, but right ventricular function increased. Non-invasive cardiac output monitoring is feasible in preterm infants with an increase in left ventricular output driven by an improvement in stroke volume during the transitional period.

Recent studies have demonstrated that surgical ventricular septal defect closure in childhood is associated with reduced functional capacity and disruption of the right ventricular force–frequency relationship during exercise. To further describe long-term cardiac function, we performed a non-invasive assessment of cardiac index during exercise in adults having undergone surgery for ventricular septal defect in early childhood.

A total of 20 patients (surgical age 2.1±1.4 years, age at examination 22.1±2.2 years) and 20 healthy, matched controls (23.4±2.1 years at examination) underwent continuous supine bicycle ergometry during MRI. Their blood flow was recorded in the ascending aorta and the pulmonary trunk at increasing exercise levels. Cardiac index, retrograde flow, and vessel diameters were determined by blinded, post hoc analyses.

The patient group had normal cardiac index at rest (2.9±0.7 L/minute/m2), which was comparable with that of the controls (3.0±0.6 L/minute/m2); however, they had a lower increase in cardiac index during exercise (reaching 7.3±1.3 L/minute/m2 at submaximal exercise) compared with controls (8.2±1.2 L/minute/m2), p<0.05. Patients had a significantly higher ascending aorta retrograde flow than controls at rest and throughout exercise. In the pulmonary artery, the retrograde flow was minimal at rest in both groups, but increased significantly in patients during exercise compared with controls.

Young adults with a surgically closed ventricular septal defect have a reduced cardiac index during exercise compared with healthy, young adults. The impaired cardiac index appears to be related to an increasing retrograde flow in the pulmonary artery with progressive exertion.

Obtaining intravenous (IV) access in patients in hemorrhagic shock is often difficult and prolonged. Failed IV attempts delay life-saving treatment. Intraosseous (IO) access may often be obtained faster than IV access. Albumin (5%) is an option for prehospital volume expansion because of the absence of interference with coagulation and platelet function.

There are limited data comparing the performance of IO and IV administered 5% albumin. The aims of this study were to compare the effects of tibial IO (TIO) and IV administration of 500 mL of 5% albumin on infusion time and hemodynamic measurements of heart rate (HR), mean arterial pressure (MAP), cardiac output (CO), and stroke volume (SV) in a swine model of hemorrhagic shock.

Sixteen male swine were divided into two groups: TIO and IV. All subjects were anesthetized and a Class III hemorrhage was achieved by exsanguination of 31% of estimated blood volume (EBV) from a femoral artery catheter. Following exsanguination, 500 mL of 5% albumin was administered under pressurized infusion (300 mmHg) by the TIO or IV route and infusion time was recorded. Hemodynamic measurements of HR, MAP, CO, and SV were collected before and after exsanguination and every 20 seconds for 180 seconds during 5% albumin infusion.

An independent t-test determined that IV 5% albumin infusion was significantly faster compared to IO (P=.01). Mean infusion time for TIO was seven minutes 35 seconds (SD=two minutes 44 seconds) compared to four minutes 32 seconds (SD=one minute 08 seconds) in the IV group. Multivariate Analysis of Variance was performed on hemodynamic data collected during the 5% albumin infusion. Analyses indicated there were no significant differences between the TIO and IV groups relative to MAP, CO, HR, or SV (P>.05).

While significantly longer to infuse 5% albumin by the TIO route, the longer TIO infusion time may be negated as IO devices can be placed more quickly compared to repeated IV attempts. The lack of significant difference between the TIO and IV routes relative to hemodynamic measures indicate the TIO route is a viable route for the infusion of 5% albumin in a swine model of Class III hemorrhage.

MuirSL , SheppardLB , Maika-WilsonA , BurgertJM , Garcia-BlancoJ , JohnsonAD , CoynerJL . A Comparison of the Effects of Intraosseous and Intravenous 5% Albumin on Infusion Time and Hemodynamic Measures in a Swine Model of Hemorrhagic Shock. Prehosp Disaster Med.2016;31(4):436–442.