Cardiac output monitoring in children: a review

Cardiac output monitoring enables physiology-directed management of critically ill children and aids in the early detection of clinical deterioration. Multiple invasive techniques have been developed and have demonstrated ability to improve clinical outcomes. However, all require invasive arterial or venous catheters, with associated risks of infection, thrombosis and vascular injury. Non-invasive monitoring of cardiac output and fluid responsiveness in infants and children is an active area of interest and several proven techniques are available. Novel non-invasive cardiac output monitors offer a promising alternative to echocardiography and have proven their ability to influence clinical practice. Assessment of perfusion remains a challenge; however, technologies such as near-infrared spectroscopy and photoplethysmography may prove valuable clinical adjuncts in the future.

Effect of tidal volume change on pressure-based prediction of fluid responsiveness in children

INTRODUCTION

It is known that pulse pressure variation and systolic pressure variation cannot predict fluid responsiveness in children. In adults, the ability of these dynamic parameters to predict fluid responsiveness is improved by increasing tidal volume. We planned to investigate whether pulse pressure variation or systolic pressure variation can predict fluid responsiveness in children when augmented by increasing tidal volume by conducting a prospective study.

METHODS

We enrolled children younger than 7 years who underwent cardiac surgery for atrial septal defect or ventricular septal defect. After sternum closure, pulse pressure variation and systolic pressure variation were continuously recorded while changing the tidal volume to 6, 10, and 14 mL/kg. Fluid loading was done with 10 mL/kg of crystalloids for 10 min, and stroke volume index was measured via transesophageal echocardiography. Children whose stroke volume index increased by more than 15% after the fluid loading were defined as responders to fluid therapy. We set primary outcome as the predictability of pulse pressure variation and systolic pressure variation for fluid responsiveness and measured the area under the curve of receiver operating characteristics curve.

RESULTS

Twenty-six children were included, of which 15 were responders. At the tidal volume of 14 mL/kg, the area under the curves of receiver operating characteristics curves of pulse pressure variation and systolic pressure variation were 0.576 (p = .517) and 0.548 (p = .678), respectively. The differences in dynamic parameters between responders and nonresponders were not significant.

DISCUSSION

Failure of pulse pressure variation or systolic pressure variation at augmented tidal volume in children may be due to difference in their arterial compliance from those of adults. Large compliance of thoracic wall may be another reason.

CONCLUSIONS

Augmented pulse pressure variation or systolic pressure variation due to increased tidal volume cannot predict fluid responsiveness in children after simple cardiac surgery.

Effects of tidal volume challenge on the reliability of plethysmography variability index in hepatobiliary and pancreatic surgeries: a prospective interventional study

BACKGROUND

The plethysmography variability index (PVI) is a non-invasive, real-time, and automated parameter for evaluating fluid responsiveness, but it does not reliably predict fluid responsiveness during low tidal volume (VT) ventilation. We hypothesized that in a 'tidal volume challenge' with a transient increase in tidal volume from 6 to 8 ml Kg- 1, the changes in PVI could predict fluid responsiveness reliably.

METHOD

We performed a prospective interventional study in adult patients undergoing hepatobiliary or pancreatic tumor resections and receiving controlled low VT ventilation. The values for PVI, perfusion index, stroke volume variation, and stroke volume index (SVI) were recorded at baseline VT of 6 ml Kg- 1, 1 min after the VT challenge (8 ml Kg- 1), 1 min after VT 6 ml Kg- 1 reduced back again, and then 5 min after crystalloid fluid bolus 6 ml kg- 1 (actual body weight) administered over 10 min. The fluid responders were identified by SVI rise ≥ 10% after the fluid bolus.

RESULTS

The area under the receiver operating characteristic curve for PVI value change (ΔPVI6-8) after increasing VT from 6 to 8 ml Kg- 1 was 0.86 (95% confidence interval, 0.76-0.96), P < 0.001, 95% sensitivity, 68% specificity, and with best cut-off value of absolute change (ΔPVI6-8) = 2.5%.

CONCLUSION

In hepatobiliary and pancreatic surgeries, tidal volume challenge improves the reliability of PVI for predicting fluid responsiveness and changes in PVI values obtained after tidal volume challenge are comparable to the changes in SVI.

Continuous cerebral blood flow monitoring: What should we do with these extra numbers?

NeoDoppler is a noninvasive monitoring device that can be attached to a patient's head to provide real-time continuous cerebral Doppler evaluation. A feasibility study shows that it can be used in operating theatres during anaesthesia to potentially guide haemodynamic management. We discuss the impact of this new device and which further research would be necessary to find its role in clinical practice.

Goal-directed fluid therapy guided by Plethysmographic Variability Index (PVI) versus conventional liberal fluid administration in children during elective abdominal surgery: A randomized controlled trial

BACKGROUND

PVI has been shown to be an accurate predictor of fluid responsiveness in paediatric patients. Evidence regarding the role of PVI to guide intraoperative fluid therapy in paediatric abdominal surgery is lacking. We aimed to assess the effect of PVI-guided fluid therapy on the volume of intraoperative fluids administered and post-operative biochemical and recovery profile in children undergoing elective abdominal surgery.

METHODS

42 children, 6 months-3 years scheduled for elective open bowel surgery were randomised to receive either 'conventional liberal intraoperative fluids' (liberal group) or 'goal-directed intraoperative fluids' (GDT group). PVI <13 was targeted in the GDT group. The primary outcome was the volume of intraoperative fluids administered. Postoperative serum lactate, base excess, hematocrit, recovery of bowel function and duration of postoperative hospital stay were the secondary outcomes.

RESULTS

The mean fluid administered intra-operatively was significantly lower in the GDT group as compared to the liberal group (24.1 ± 9.6 mL/kg vs 37.0 ± 8.9 mL/kg, p < 0.001). The postoperative hemoglobin concentration (g%) was significantly lower in the liberal group as compared to the GDT group (8.1 ± 1.3 vs 9.2 ± 1.4, p = 0.008). Recovery of bowel function (hours) was significantly delayed in the liberal group as compared to the GDT group (58.2 ± 17.9 vs 36.5 ± 14.1, p < 0.001).

CONCLUSION

Intraoperative PVI-guided fluid therapy significantly reduces the volume of intravenous crystalloids administered to children undergoing open bowel surgery. These children also had faster recovery of bowel function and less hemodilution in the immediate postoperative period, compared to those who received liberal intraoperative fluid therapy.

TYPE OF STUDY

Randomized Clinical Trial.

LEVEL OF EVIDENCE

Treatment Study (LEVEL 1).

Non-invasive measurement of digital plethysmographic variability index to predict fluid responsiveness in mechanically ventilated children: A systematic review and meta-analysis of diagnostic test accuracy studies

BACKGROUND

To date, the use of the plethysmographic variability index (PVI) has not been recommended to guide fluid management in the paediatric surgical population. This systematic review and meta-analysis aimed to summarise available evidence about the diagnostic accuracy of digital PVI to predict fluid responsiveness in mechanically ventilated children.

METHODS

We searched the Pubmed, Embase and Web of Science databases, from inception to January 2022, to identify all relevant studies that investigated the ability of the PVI recorded at the finger to predict fluid responsiveness in mechanically ventilated children. Using a random-effects model, we calculated pooled values of diagnostic odds ratio, sensitivity, and specificity of PVI to predict the response to fluid challenge.

RESULTS

Eight studies met the inclusion criteria with a total of 283 patients and 360 fluid challenges. All the studies were carried out in a surgical setting. The area under the summary receiver operating characteristic curve of PVI to predict fluid responsiveness was 0.82. The pooled sensitivity, specificity, and diagnostic odds ratio of PVI for the overall population were 72.4% [95% CI: 65.3-78.7], 65.9% [58.5-72.8], and 9.26 [5.31-16.16], respectively.

CONCLUSION

Our results suggest that digital PVI is a reliable predictor for fluid responsiveness in mechanically ventilated children in the perioperative setting. The diagnostic performance of digital PVI reported in our work for discrimination between responders and non-responders to the fluid challenge was however not as high as previously reported in the adult population.

Comparative efficacy of finger versus forehead Plethysmographic Variability Index monitoring in pediatric surgical patients

INTRODUCTION

The Plethysmographic Variability Index can be measured by both finger and forehead probes. Vasoconstriction may jeopardize the reliability of finger PVI measurements in pediatric patients undergoing surgery. However, forehead vasculature exhibits more marked resistance to alterations in the vasomotor tonus.

OBJECTIVE

Our aim was to compare the Plethysmographic Variability Index measured via finger or forehead probes in mechanically ventilated pediatric surgery patients in terms of their ability to predict fluid responsiveness as well as to determine the best cut-off values for these two measurements.

MATERIALS AND METHODS

A total of 50 pediatric patients undergoing minor elective surgery were included after provision of parental consent and ethics committee approval. Perfusion index measured at the finger or forehead and Plethysmographic Variability Index monitoring comprised the primary assessments. Hemodynamic parameters monitored included perfusion index, Plethysmographic Variability Index, and cardiac output. A ≥ 15% increase in cardiac output following passive leg raise maneuver was considered to show fluid responsiveness. Two groups were defined based on fluid responsiveness: Group R (responsive) and Group NR (non-responsive). Student's t-test, Mann-Whitney U test, DeLong test, and ROC were used for statistical analysis.

RESULTS

The area under curve for finger and forehead Plethysmographic Variability Index prior to passive leg raise maneuver were 0.699 (p = .011) and 0.847 (p < .001), respectively. The sensitivity for finger and forehead measurements at a cut-off value of ≤14% was 92.9% and 96.4%, and 45.4% and 72.7%, respectively.

CONCLUSION

Although forehead and finger Plethysmographic Variability Index monitoring were similarly sensitive in predicting fluid responsiveness in pediatric surgical patients, the former method provided higher specificity. The best cut-off value for PVI measurements with forehead and finger probes was found to be 14%.

Perioperative fluid management in children: an updated review

Background: Perioperative fluid management in children has been a major topic for debate. Objectives: Our aim is to review the current evidence on perioperative fluid management in children including: type of fluid, administration rates, preoperative fluid intake and monitoring techniques. Design: Narrative review. Method: Following the PRISMA-S guidelines we performed a search (2010-March 2022) in databases Medline (through PubMed) and Cochrane Library. 4297 citations were found and screened by two independent researchers. After screening, 64 articles were withheld for our review. Results: The perioperative administration of isotonic fluids is safer than hypotonic solutions, concerning the development of hyponatremia. A balanced isotonic solution with 1-2,5% glucose should be used as perioperative maintenance IV fluid in children (1 month to 18 years). Colloids can be used in children when inadequate effect in volume correction is achieved with crystalloids. The preferred synthetic colloid for children is a third generation HES in a balanced solution. To date, most clinicians use the “4-2-1 rule” for calculating fluid rate. This may not be the optimal fluid rate, as little research has been done. Preoperative fasting for clear fluids should be limited to 1 hour, children should even be encouraged to drink up until 1 hour before induction. Respiratory variation of aortic blood flow peak velocity (ΔVpeak) with echocardiography is currently the most reliable technique for evaluating fluid responsiveness in children.

[Hemodynamic monitoring in pediatric anesthesia]

Perioperative mortality and morbidity in childhood essentially depend on the quality of the anesthesia. The Safe Anesthesia for every Tot (SafeTots) initiative takes this into account and has defined normotension, normovolemia and normal heart rate as quality criteria in pediatric anesthesia. Appropriate monitoring of pediatric hemodynamics is necessary to fulfil these criteria. This article provides an overview of currently used methods and techniques for instrumental and non-instrumental cardiovascular monitoring in children. The current study situation, recommendations and guidelines on the application as well as practical aspects of the measurement methods are explained as far as possible. For a better understanding, procedures not routinely used in clinical practice are described in more detail.

Perfusion index: Physical principles, physiological meanings and clinical implications in anaesthesia and critical care

Photoplethysmography (PPG) has been extensively used for pulse oximetry monitoring in anaesthesia, perioperative and intensive care. However, some components of PPG signal have been employed for other purposes, such as non-invasive haemodynamic monitoring. Perfusion index (PI) is derived from PPG signal and represents the ratio of pulsatile on non-pulsatile light absorbance or reflectance of the PPG signal. PI determinants are complex and interlinked, involving and reflecting the interaction between peripheral and central haemodynamic characteristics, such as vascular tone and stroke volume. Recently, several studies have shed light on the interesting performances of this variable, especially assessing regional or neuraxial block success, and haemodynamic monitoring in anaesthesia, perioperative and intensive care. Nevertheless, no review has yet been published concerning the interest of PI in these fields. In this narrative review will be exposed first the physiological and pathophysiological determinants of PI, and then the mean to measure this value as well as its potential limitations. In the second part, the existing data concerning usefulness of PI in different clinical settings such as operating theatres, intensive care units and emergency departments will be presented and discussed. Finally, the perspectives concerning the use of PI and mentioned aspects that should be explored regarding this tool will be underlined.

[Comparison of pulse pressure variation, stroke volume variation, and plethysmographic variability index in pediatric patients undergoing craniotomy]

OBJECTIVE

To compare well-known preload dynamic parameters intraoperatively including stroke volume variation (SVV), pulse pressure variation (PPV), and plethysmographic variability index (PVI) in children who underwent craniotomy for epileptogenic lesion excision.

METHODS

A total of 30 children aged 0 to 14 years undergoing craniotomy for intracranial epileptogenic lesion excision were enrolled. During surgery, we measured PPV, SVV (measured by the Flotrac/Vigileo device), and PVI (measured by the Masimo Radical-7 monitor) simultaneously and continuously. Preload dynamic parameter measurements were collected at predefined steps: after induction of anesthesia, during opening the skull, intraoperative electroencephalogram monitoring, excision of epileptogenic lesion, skull closure, at the end of the operation. After exclusion of outliers, agreement among SVV, PPV, and PVI was assessed using repeated measures of Bland-Altman approach. The 4-quadrant and polar plot techniques were used to assess the trending ability among the changes in the three parameters.

RESULTS

The mean SVV, PPV, and PVI were 8%±2%, 10%±3%, and 15%±7%, respectively during surgery. We analyzed a total of 834 paired measurements (3 to 8 data sets for each phase per patient). Repeated measures Bland-Altman analysis identified a bias of -2.3 and 95% confidence intervals between -1.9 and -2.7 (95% limits of agreement between -6.0 and 1.5) between PPV and SVV, showing significant correlation at all periods. The bias between PPV and PVI was -5.0 with 95% limits of agreement between -20.5 and 10.5, and that between SVV and PVI was -7.5 with 95% limits of agreement between -22.7 and 7.8, both not showing significant correlation. Reflected by 4-quadrant plots, the con-cordance rates showing the trending ability between the changes in PPV and SVV, PPV and PVI, SVV and PVI were 88.6%, 50.4%, and 50.1%, respectively. The concordance rate between PPV and SVV was higher (92.7%) in children aged less than 3 years compared with those aged 3 and more than 3 years. The mean angular bias, radial limits of agreement, and angular concordance rate in the polar analysis were not clinically acceptable in the changes between arterial pressure waveform-based parameters and volume-based PVI (PPV vs. PVI: angular mean bias 8.4°, angular concordance rate 29.9%; SVV vs. PVI: angular mean bias 2.4°, angular concordance rate 29.1%). There was a high concordance between the two arterial pressure waveform-based parameters reflected by the polar plot (angular mean bias -0.22°, angular concordance rate 86.6%).

CONCLUSION

PPV can be viewed as a surrogate for SVV, especially in children aged less than 3 years. The agreement between arterial pressure waveform-based preload parameters (PPV and SVV) and PVI is poor and these two should not be considered interchangeable. Attempt to combine PVI and PPV for improving the anesthesiologist's ability to monitor cardiac preload in major pediatric surgery is warranted.

Predicting hypotension during anesthesia: Variation in pulse oximetry plethysmography predicts propofol-induced hypotension in children

BACKGROUND

The development of hypotension on administration of intravenous propofol is common and independently associated with adverse outcomes. Identifying patients with a high risk for anesthesia-induced hypotension may help anesthesiologists prepare for such an event.

AIM

The authors hypothesized that propofol-induced hypotension is predictable by variables related to fluid responsiveness and investigated such variables to determine the factors which can predict hypotensive events.

METHODS

Patients 3-6 years of age who underwent general were included. Intravenous midazolam 0.1 mg kg^-1 was administered as premedication, and preoperative noninvasive blood pressure, heart rate, perfusion index, pleth variability index, and respiratory variation of pulse oximetry plethysmographic waveform were measured. Intravenous propofol 2.5 mg kg^-1 was given, and blood pressure was measured 5 times at 1-min intervals. Subjects with significant hypotension (mean blood pressure decrease ≥20%) were allocated to the hypotensive group; those without significant hypotension were allocated to the relatively normotensive group.

RESULTS

Of 77 patients, 50 (64.9%) developed significant hypotension. Patients in the hypotensive group exhibited significantly higher respiratory variation of pulse oximetry plethysmographic waveform (mean difference 11 [3.3] [95% confidence interval 4.9-18.1]; p = .001) and higher pleth variability index (mean difference 7.1 [2.8] [95% confidence interval 1.6-12.6]; p = .013) than the normotensive group. The areas under the receiver operating characteristic curve for respiratory variation of pulse oximetry plethysmographic waveform and pleth variability index were 0.722 and 0.649, respectively.

CONCLUSION

High preoperative respiratory variation of pulse oximetry plethysmographic waveform and pleth variability index were both independently associated with propofol-induced hypotension in children.

Assessment of Volume Status and Fluid Responsiveness in Small Animals

Intravenous fluids are an essential component of shock management in human and veterinary emergency and critical care to increase cardiac output and improve tissue perfusion. Unfortunately, there are very few evidence-based guidelines to help direct fluid therapy in the clinical setting. Giving insufficient fluids and/or administering fluids too slowly to hypotensive patients with hypovolemia can contribute to continued hypoperfusion and increased morbidity and mortality. Similarly, giving excessive fluids to a volume unresponsive patient can contribute to volume overload and can equally increase morbidity and mortality. Therefore, assessing a patient's volume status and fluid responsiveness, and monitoring patient's response to fluid administration is critical in maintaining the balance between meeting a patient's fluid needs vs. contributing to complications of volume overload. This article will focus on the physiology behind fluid responsiveness and the methodologies used to estimate volume status and fluid responsiveness in the clinical setting.

Prediction of fluid responsiveness using lung recruitment manoeuvre in paediatric patients receiving lung-protective ventilation: A prospective observational study

BACKGROUND

Pressure-based dynamic variables are poor predictors of fluid responsiveness in children, and their predictability is expected to reduce further during lung-protective ventilation with a low tidal volume.

OBJECTIVE

We hypothesised that lung recruitment manoeuvre (LRM)-induced changes in dynamic variables improve their ability to predict fluid responsiveness in children.

DESIGN

Prospective observational study.

SETTING

Tertiary care children's hospital, single-centre study performed from June 2017 to May 2019.

PATIENTS

We included patients less than 7 years of age undergoing cardiac surgery. Neonates and patients with pulmonary hypertension, significant dysrhythmia, ventricular ejection fraction of less than 30% or pulmonary disease were excluded.

INTERVENTION

All patients were provided with lung-protective volume-controlled ventilation (tidal volume 6 ml kg-1, positive end-expiratory pressure 6 cmH2O). A LRM was applied with a continuous inspiratory pressure of 25 cmH2O for 20 s.

MAIN OUTCOME MEASURE

The ability of dynamic variables to predict fluid responsiveness was evaluated by the area under the receiver operating characteristic curve [area under the curve (AUC)]. Fluid responsiveness was defined as an increase in the cardiac index by more than 15% with crystalloid administration (10 ml kg-1).

RESULTS

Thirty patients were included in the final analysis, of whom 19 were responders. The baseline pleth variability index (PVI) (AUC 0.794, 95% confidence interval 0.608 to 0.919, P < 0.001) and LRM-induced PVI (AUC 0.711, 95% confidence interval 0.517 to 0.861, P = 0.026) could predict fluid responsiveness. The respiratory variation of pulse oximetry photoplethysmographic waveform and pulse pressure variation did not predict fluid responsiveness regardless of the LRM.

CONCLUSION

The PVI is effective in predicting fluid responsiveness in paediatric patients with lung-protective ventilation regardless of a LRM. However, the LRM did not improve the ability of the other dynamic variables to predict fluid responsiveness in these patients.

CLINICAL TRIAL REGISTRATION

www.clinicaltrials.gov identifier: NCT03184961.

Lessons Learned From the First Pilot Study of the Compensatory Reserve Index After Congenital Heart Surgery Requiring Cardiopulmonary Bypass

BACKGROUND

Early warning systems that utilize dense physiologic data and machine learning may aid prediction of decompensation after congenital heart surgery (CHS). The Compensatory Reserve Index (CRI) analyzes changing features of the pulse waveform to predict hemodynamic decompensation in adults, but it has never been studied after CHS. This study sought to understand the feasibility, safety, and potential utility of CRI monitoring after CHS with cardiopulmonary bypass (CPB).

METHODS

A single-center prospective pilot cohort of patients undergoing pulmonary valve replacement was studied. Compensatory Reserve Index was continuously measured from preoperative baseline through the first 24 postoperative hours. Average CRI values during selected procedural phases were compared between patients with an intensive care unit (ICU) length of stay (LOS) <3 days versus LOS ≥3 days.

RESULTS

Twenty-three patients were enrolled. On average, 17,445 (±3,152) CRI data points were collected and 0.33% (±0.40) of data were missing per patient. There were no adverse events related to monitoring. Five (21.7%) patients had an ICU LOS ≥3 days. Compared to the ICU LOS <3 days group, the ICU LOS ≥3 days group had a greater decrease in CRI from baseline to immediately after CPB (-0.3 ± 0.1 vs -0.1 ± 0.2, P = .003) and were less likely to recover to baseline CRI during the monitoring period (20% vs 83%, P = .017).

CONCLUSIONS

Compensatory Reserve Index monitoring after CHS with CPB seems feasible and safe. Early changes in CRI may precede meaningful clinical outcomes, but this requires further study.

Role of TFA-1 adhesive forehead sensors in predicting fluid responsiveness in anaesthetised children: A prospective cohort study

BACKGROUND

The TFA-1 adhesive forehead sensor is a newly developed pulse oximeter for the measurement of the plethysmographic variability index (PVI) at the forehead, and for the rapid detection of changes in oxygen saturation during low perfusion.

OBJECTIVES

We evaluated the ability of the TFA-1 sensor to predict fluid responsiveness in children under general anaesthesia.

DESIGN

Prospective cohort study.

SETTING

Single tertiary care children's hospital.

PATIENTS

Thirty-seven children aged 1 to 5 years under general anaesthesia and requiring invasive arterial pressure monitoring.

MAIN OUTCOME MEASURES

The baseline PVI of TFA-1 and finger sensors, respiratory variation of aorta blood flow peak velocity (ΔVpeak) and stroke volume index (SVI) obtained using transthoracic echocardiography were assessed. After fluid loading of 10 ml kg crystalloids over 10 min, SVI was reassessed. Responders were defined as those with an increase in SVI greater than 15% from the baseline. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the predictive ability of the PVI of TFA-1 and finger sensors and ΔVpeak for fluid responsiveness.

RESULTS

Seventeen (56.6%) patients responded to volume expansion. Before fluid loading, the PVI of TFA-1 and finger sensors and ΔVpeak (mean ± SD) of the responders were 11.2 ± 4.4, 11.4 ± 5.1 and 14.8 ± 3.9%, respectively, and those of the nonresponders were 7.4 ± 3.9, 8.1 ± 3.6 and 11.0 ± 3.3%, respectively. ROC curve analysis indicated that the PVI of TFA-1 and finger sensors and ΔVpeak could predict fluid responsiveness. The areas under the curve were 0.8 [P = 0.00; 95% confidence interval (CI) 0.60 to 0.91], 0.7 (P = 0.02; 95% CI 0.53 to 0.87) and 0.8 (P = 0.00; 95% CI 0.59 to 0.91), respectively. The cut-off values for the PVI of TFA-1 and finger sensors and ΔVpeak were 6.0, 9.0 and 10.6%, respectively.

CONCLUSION

The PVI of TFA-1 forehead sensor is a good alternative, but is not superior to the finger sensor and ΔVpeak in evaluating fluid responsiveness in mechanically ventilated children under general anaesthesia.

CLINICAL TRIAL REGISTRATION

www.clinicaltrials.gov, NCT03132480.

Fluid responsiveness in the pediatric population

It is challenging to predict fluid responsiveness, that is, whether the cardiac index or stroke volume index would be increased by fluid administration, in the pediatric population. Previous studies on fluid responsiveness have assessed several variables derived from pressure wave measurements, plethysmography (pulse oximeter plethysmograph amplitude variation), ultrasonography, bioreactance data, and various combined methods. However, only the respiratory variation of aortic blood flow peak velocity has consistently shown a predictive ability in pediatric patients. For the prediction of fluid responsiveness in children, flow- or volume-dependent, noninvasive variables are more promising than pressure-dependent, invasive variables. This article reviews various potential variables for the prediction of fluid responsiveness in the pediatric population. Differences in anatomic and physiologic characteristics between the pediatric and adult populations are covered. In addition, some important considerations are discussed for future studies on fluid responsiveness in the pediatric population.

Actualités sur le sepsis et le choc septique de l’enfant

L’incidence du sepsis de l’enfant augmente en réanimation pédiatrique. La définition du sepsis et du choc septique de l’enfant est amenée à évoluer à l’instar de celle du choc septique de l’adulte pour détecter les patients nécessitant une prise en charge urgente et spécialisée. La prise en charge d’un patient septique repose sur une oxygénothérapie, une expansion volémique au sérum salé isotonique, une antibiothérapie et un transfert dans un service de réanimation ou de surveillance continue pédiatrique. Le taux et la cinétique d’élimination du lactate plasmatique est un bon critère diagnostic et pronostic qui permet de guider la prise en charge. La présence de plusieurs défaillances d’organes ou une défaillance circulatoire aiguë signe le diagnostic de sepsis encore dit sévère, et leur persistance et/ou la non-correction de l’hypotension artérielle malgré un remplissage vasculaire d’au moins 40 ml/kg définit le choc septique chez l’enfant. Dans ce cas, la correction rapide de l’hypotension artérielle persistante repose sur la noradrénaline initiée sur une voie intraveineuse périphérique dans l’attente d’un accès veineux central. L’échographie cardiaque est un examen clé de l’évaluation hémodynamique du patient, pour guider la poursuite de l’expansion volémique ou détecter une cardiomyopathie septique. Des thérapeutiques additionnelles ont été proposées pour prendre en charge certains patients avec des défaillances d’organes particulières. L’immunomonitorage et la modulation sont un ensemble de techniques qui permettent la recherche et le traitement de certaines complications. La Surviving Sepsis Campaign a permis d’améliorer la prise en charge de ces patients par l’implémentation d’algorithmes de détection et de prise en charge du sepsis de l’enfant. Une révision pédiatrique de cette campagne est attendue prochainement.