Resuscitating the macro- vs. microcirculation in septic shock.

PURPOSE OF REVIEW: This review summarizes current literature about the relationships between macro and microcirculation and their practical clinical implications in children with septic shock. RECENT FINDINGS: Current evidence from experimental and clinical observational studies in children and adults with septic shock reveals that the response to treatment and resuscitation is widely variable. Furthermore, there is a loss of hemodynamic coherence, as resuscitation-induced improvement in macrocirculation (systemic hemodynamic parameters) does not necessarily result in a parallel improvement in the microcirculation. Therefore, patient-tailored monitoring is essential in order to adjust treatment requirements during resuscitation in septic shock. Optimal monitoring must integrate macrocirculation (heart rate, blood pressure, cardiac output, and ultrasound images), microcirculation (videomicroscopy parameters and capillary refill time) and cellular metabolism (lactic acid, central venous blood oxygen saturation, and difference of central venous to arterial carbon dioxide partial pressure). SUMMARY: There is a dire need for high-quality studies to assess the relationships between macrocirculation, microcirculation and tissue metabolism in children with septic shock. The development of reliable and readily available microcirculation and tissue perfusion biomarkers (other than lactic acid) is also necessary to improve monitoring and treatment adjustment in such patients.

Doppler ultrasound in the assessment of renal perfusion before and during continuous kidney replacement therapy in the pediatric intensive care unit.

BACKGROUND: This study aimed to assess observer variability and describe renal resistive index (RRI) and pulsatility index (PI) before and after onset of continuous kidney replacement therapy (CKRT). A secondary objective was to correlate Doppler ultrasound findings with those from direct measurement of renal blood flow (RBF). METHODS: This is a prospective observational study in hemodynamically stable Maryland piglets with and without acute kidney injury (AKI) and in hemodynamically unstable critically ill children requiring CKRT. Doppler-based RRI and PI were assessed for each subject. Measurements were made by two different operators (pediatric intensivists) before and after CKRT onset. RESULTS: Observer variability assessment in the measurement of RRI and PI rendered a moderate correlation for both RRI (ICC 0.65, IQR 0.51-0.76) and PI (ICC 0.63, IQR 0.47-0.75). RRI and PI showed no correlation with RBF or urine output. Baseline RRI and PI were normal in control piglets [RRI 0.68 (SD 0.02), PI 1.25 (SD 0.09)] and those with AKI [RRI 0.68 (SD 0.03), PI 1.20 (SD 0.13)]. Baseline RRI and PI were elevated in critically ill children (RRI 0.85, PI 2.0). PI and RRI did not change with CKRT in any study group. CONCLUSIONS: Observer variability between inexperienced pediatric intensivists was comparable with that between senior and junior operators. Doppler-based calculations did not correlate with invasive measurements of RBF. RRI and PI were normal in hemodynamically stable piglets with and without AKI. RRI and PI were high in hemodynamically unstable patients requiring CKRT. RRI and PI did not change after CKRT onset, despite changes in hemodynamic status. A higher resolution version of the Graphical abstract is available as Supplementary information.

Hemodynamic disturbances and oliguria during continuous kidney replacement therapy in critically ill children.

BACKGROUND: About 1.5% of patients admitted to the Pediatric Intensive Care Unit (PICU) will require continuous kidney replacement therapy (CKRT)/renal replacement therapy (CRRT). Mortality of these patients ranges from 30 to 60%. CKRT-related hypotension (CKRT-RHI) can occur in 19-45% of patients. Oliguria after onset of CKRT is also common, but to date has not been addressed directly in the scientific literature. METHODS: A prospective observational study was conducted to define factors involved in the hemodynamic changes that take place during the first hours of CKRT, and their relationship with urinary output. RESULTS: Twenty-five patients who were admitted to a single-center PICU requiring CKRT between January 1, 2014, and December 31, 2018, were included, of whom 56.3% developed CKRT-RHI. This drop in blood pressure was transient and rapidly restored to baseline, and significantly improved after the third hour of CKRT, as core temperature and heart rate decreased. Urine output significantly decreased after starting CKRT, and 72% of patients were oliguric after 6 h of therapy. Duration of CKRT was significantly longer in patients presenting with oliguria than in non-oliguric patients (28.7 vs. 7.9 days, p = 0.013). CONCLUSIONS: The initiation of CKRT caused hemodynamic instability immediately after initial connection in most patients, but had a beneficial effect on the patient's hemodynamic status after 3 h of therapy, presumably owing to decreases in body temperature and heart rate. Urine output significantly decreased in all patients and was not related to negative fluid balance, patient's hemodynamic status, CKRT settings, or kidney function parameters.

Evaluation of the pediatric life support instructors courses.

OBJECTIVE: To evaluate the results and quality of pediatric cardiopulmonary resuscitation (CPR) instructor training courses. METHODS: A retrospective analysis was performed of the results of 24 pediatric CPR instructor courses held over 21 years (1999 to 2019). The results of participants' evaluation of theory and practice sessions were analyzed. In addition, participants were asked to answer an anonymous survey to assess their opinion on the quality of theory and practice lessons, course organization and methodology, and instructor training. The results were compared by professional groups. RESULTS: A total of 560 participants completed the instructor course. Of them, 554 passed theory and practice tests (98.9 %). The mean score obtained in theory tests was 9.2 (0.8) out of 10. The mean score obtained in all practice tests was > 3.5 out of 5. Participants evaluated all the aspects of the course (theory and practice content, organization, teaching methodology, and instructors) with mean scores over 8 out of 10. CONCLUSIONS: Specific pediatric and neonatal CPR instructor courses are a cornerstone in the process of CPR training and ensuring the homogeneity and quality of training. Most of the participants obtained the qualification of instructors and their evaluation of the course was very positive.

Hemodynamic impact of the connection to continuous renal replacement therapy in critically ill children.

BACKGROUND: Continuous renal replacement therapy (CRRT) is the treatment of choice for critically ill children with acute kidney injury. Hypotension after starting CRRT is frequent but very few studies have analyzed its incidence and clinical relevance. METHODS: A prospective, observational study was performed including critically ill children treated with CRRT between 2010 and 2014. Hemodynamic data and connection characteristics were collected before, during, and 60 min after CRRT circuit connection. Hypotension with the connection was defined as a decrease in > 20% of the mean arterial pressure from baseline or when intravenous fluid resuscitation or an increase in vasopressors was required. RESULTS: One hundred sixty-one connections in 36 children (median age 18.8 months) were analyzed. Twenty-eight patients (77.8%) were in the postoperative period of cardiac surgery, 94% had mechanical ventilation, and 86.1% had vasopressors. The heparinized circuit priming solution was discarded in 8.7% and infused to the patient in 18% of the connections. The circuit was re-primed in the remaining 73.3% using albumin (79.3%), red blood cells (4.5%), or another crystalloid solution without heparin (16.2%). Hypotension occurred in 49.7% of the connections a median of 5 min after the beginning of the therapy. Fluid resuscitation was required in 38.5% and the dose of vasopressors was increased in 12.4% of the connections. There was no relationship between hypotension and age or weight. Re-priming the circuit with albumin reduced the incidence of hypotension from 71.4 to 44.6% (p = 0.004). CONCLUSIONS: Hypotension after the connection to CRRT is very frequent in critically ill children. Re-priming the circuit with albumin could improve hemodynamics during connection.

Hemodynamic Effects of Connection to Continuous Renal Replacement Therapy in a Pediatric Animal Model.

To assess the hemodynamic effects of connection to continuous renal replacement therapy (CRRT) in a pediatric experimental animal model. Prospective experimental study was performed using piglets between 2 and 3 months of age and 9-11 kg. CRRT with a PrismaflexR monitor and HF20 filter (surface of 0.2 m2 ) was started after monitoring and anesthetic induction with an initial blood flow at 20 mL/min with 10 mL/min increases every minute until the goal flow of 5 mL/kg/min was achieved. Heart rate, blood pressure, central venous pressure, cardiac index, and renal blood flow were registered at baseline, 5, 15, 30, 60, 120, 180, 240, and 360 min. IBM SPSS Statistics 20.0 package was used for analysis. A P value of <0.05 was considered statistically significant. Thirty-four piglets were studied. Blood pressure, cardiac output, and systemic vascular resistance significantly decreased 5-min after CRRT connection (mean arterial pressure from 85.5 to 70.8 mm Hg, P < 0.001, cardiac index from 3.6 to 3.3 L/min/m2 P = 0.024, and systemic vascular resistance index from 1759 to 1607 dyn.s/cm5 P = 0.012). No significant changes were found in renal blood flow or central venous pressure. All parameters gradually increased at 15 and 30 min after connection but complete recovery was never achieved. Connection to CRRT produces a significant decrease in arterial pressure, cardiac index, and peripheral vascular resistances in hemodynamically stable piglets.

Evaluation of sublingual microcirculation in a paediatric intensive care unit: prospective observational study about its feasibility and utility.

BACKGROUND: Evaluation of the microcirculation in critically ill patients is usually done by means of indirect parameters. The aim of our study was to evaluate the functional state of the microcirculation by direct visualization of sublingual microcirculation using Sidestream Dark Field Imaging, to determine the correlation between these findings and other parameters that are commonly used in the clinical practice and to assess the applicability of the systematic use of this technique in critically ill children. METHODS: A prospective observational study was carried out in a Pediatric Intensive Care Unit (PICU) of a tertiary referral hospital. All patients admitted to the PICU during a three-month period were included in the study after obtaining the informed consent from the patient. Systematic evaluation of sublingual microcirculation was done in these patients (Total Vessel Density, Proportion of Perfused Vessels, Perfused Vessel Density, De Backer Score, Microvascular Flow Index, Heterogeneity Index) within the first day of admission (T1) and between the second and third day of admission (T2). Other clinical, hemodynamic, and biochemical parameters were measured and registered simultaneously. When the evaluation of the microcirculation was not feasible, the reason was registered. Descriptive analysis of our findings are expressed as means, medians, standard deviations and interquartile ranges. Mann-Whitney-Wilcoxon and Fisher tests were used to compare variables between patients with and without evaluation of the microcirculation. Pearson Correlation Coefficient (ρ) was used to evaluate the correlation between microcirculatory parameters and other clinical parameters. RESULTS: One hundred fine patients were included during the study period. Evaluation of the microcirculation was feasible in 18 patients (17.1%). 95.2% of them were intubated. The main reason for not evaluating microcirculation was the presence of respiratory difficulty or the absence of collaboration (95.1% on T1 and 68.9% on T2). Evaluated patients had a higher prevalence of intubation and ECMO at admission (72.2% vs. 14.9% and 16.6% vs. 1.1%, respectively), and longer median duration of mechanical ventilation (0 vs. 6.5 days), vasoactive drugs (0 vs. 3.5 days) and length of stay (3 vs. 16.5 days) than non-evaluated patients. There was a moderate correlation between microcirculatory parameters and systolic arterial pressure, central venous pressure, serum lactate and other biochemical parameters used for motoring critically ill children. CONCLUSIONS: Systematic evaluation of microcirculation in critically ill children is not feasible in the unstable critically ill patient, but it is feasible in stable critically ill children. Microcirculatory parameters show a moderate correlation with other parameters that are usually monitored in critically ill children.

Paediatric cardiopulmonary resuscitation training program in Latin-America: the RIBEPCI experience.

BACKGROUND: To describe the design and to present the results of a paediatric and neonatal cardiopulmonary resuscitation (CPR) training program adapted to Latin-America. METHODS: A paediatric CPR coordinated training project was set up in several Latin-American countries with the instructional and scientific support of the Spanish Group for Paediatric and Neonatal CPR. The program was divided into four phases: CPR training and preparation of instructors; training for instructors; supervised teaching; and independent teaching. Instructors from each country participated in the development of the next group in the following country. Paediatric Basic Life Support (BLS), Paediatric Intermediate (ILS) and Paediatric Advanced (ALS) courses were organized in each country adapted to local characteristics. RESULTS: Five Paediatric Resuscitation groups were created sequentially in Honduras (2), Guatemala, Dominican Republican and Mexico. During 5 years, 6 instructors courses (94 students), 64 Paediatric BLS Courses (1409 students), 29 Paediatrics ILS courses (626 students) and 89 Paediatric ALS courses (1804 students) were given. At the end of the program all five groups are autonomous and organize their own instructor courses. CONCLUSIONS: Training of autonomous Paediatric CPR groups with the collaboration and scientific assessment of an expert group is a good model program to develop Paediatric CPR training in low- and middle income countries. Participation of groups of different countries in the educational activities is an important method to establish a cooperation network.

Constipation in the Critically Ill Child: Frequency and Related Factors.

OBJECTIVE: To analyze the incidence and factors associated with constipation in critically ill children. STUDY DESIGN: We performed a prospective observational study that included children admitted to the pediatric intensive care unit for more than 3 days. Constipation was defined as more than 3 days without a bowel movement. Relationships between constipation and demographic data; clinical severity score; use of mechanical ventilation, use of vasoconstrictors, sedatives, and muscle relaxants; nutritional data; electrolyte disturbances; and clinical course were analyzed. RESULTS: Constipation developed in 46.7% of the 150 patients studied (mean age, 34.3 ± 7.1 months). It was most common in postoperative, older, and higher-body-weight patients, and in those with fecal continence (P < .01). Compared with patients without constipation, patients with constipation had higher severity scores and more frequently received midazolam, fentanyl, muscle relaxants, and inotropic support (P < .05). Patients with constipation also started nutrition later and with a lower volume of nutrition (P < .01). There were no between-group differences in mortality or length of pediatric intensive care unit stay. In multivariate analysis, independent factors associated with constipation were body weight (OR, 1.08; 95% CI, 1.03-1.13), Pediatric Index of Mortality 2 score (OR, 1.05; 95% CI, 1.02-1.09), admission after surgery (OR, 7.64; 95% CI, 2.56-22.81), and treatment with vasoconstrictors (OR, 10.28; 95% CI, 3.53-29.93). CONCLUSION: Constipation is common in critically ill children. Body weight, Pediatric Index of Mortality 2 clinical severity score, admission after surgery, and the need for vasoconstrictor therapy are major independent risk factors associated with constipation.

Measurement of cardiac output in children by pressure-recording analytical method.

We evaluated two pressure-recording analytical method (PRAM) software versions (v.1 and v.2) to measure cardiac index (CI) in hemodynamically stable critically ill children and investigate factors that influence PRAM values. The working hypothesis was that PRAM CI measurements would stay within normal limits in hemodynamically stable patients. Ninety-five CI PRAM measurements were analyzed in 47 patients aged 1-168 months. Mean CI was 4.1 ± 1.4 L/min/m(2) (range 2.0-7.0). CI was outside limits defined as normal (3-5 L/min/m(2)) in 53.7% of measurements (47.8% with software v.1 and 69.2% with software v.2, p = 0.062). Moreover, 14.7% of measurements were below 2.5 L/min/m(2), and 13.6% were above 6 L/min/m(2). CI was significantly lower in patients with a clearly visible dicrotic notch than in those without (3.7 vs. 4.6 L/min/m(2), p = 0.004) and in children with a radial arterial catheter (3.5 L/min/m(2)) than in those with a brachial (4.4 L/min/m(2), p = 0.021) or femoral catheter (4.7 L/min/m(2), p = 0.005). By contrast, CI was significantly higher in children under 12 months (4.2 vs. 3.6 L/min/m(2), p = 0.034) and weighing under 10 kg (4.2 vs. 3.6 L/min/m(2), p = 0.026). No significant differences were observed between cardiac surgery patients and the rest of children. A high percentage of CI measurements registered by PRAM were outside normal limits in hemodynamically stable, critically ill children. CI measured by PRAM may be influenced by the age, weight, location of catheter, and presence of a dicrotic notch.

Population pharmacokinetics of omeprazole in critically ill pediatric patients.

BACKGROUND: To develop a population pharmacokinetic model for intravenous omeprazole in critically ill children. METHODS: One hundred eighty-six omeprazole concentration-time data from 40 critically ill children were analyzed using the nonlinear mixed-effects approach with the nonlinear mixed-effects modeling software, version 7.2 software. Patients were randomized into 2 groups and received intravenous omeprazole at a dose of 0.5 or 1 mg/kg twice daily. Blood samples were drawn at 0.5, 2, 6, 12, 24, and 48 hours after the first infusion. RESULTS: The pharmacokinetic profile was best described by a 2-compartment model with a first-order elimination process. Between-patient variability could only be associated with plasma clearance (CL). The typical values for plasma CL were 24.9 L·h·70 kg (10.08%), with a distributional clearance of 53.9 L·h·70 kg (11.00%) and central and peripheral compartment distribution volumes of 4.23 L/70 kg (19.62%) and 674 L/70 kg (0.89%), respectively. Allometric size models seemed to predict changes adequately in all the pharmacokinetic parameters. High values of between-patient variability of CL [75.50% (2.60%)] and residual variability [130.0% (5.26%)] were still found in the final model. Model-based simulations suggested that the most suitable dose was 1 mg/kg because this yielded similar exposure (defined by the area under the concentration-time curve) to that obtained in adults after a 20-mg dose of omeprazole intravenously. CONCLUSIONS: An allometric size model allows changes to be predicted in all the pharmacokinetic parameters, making dose adjustment by body weight important to achieve the most effective omeprazole exposure. This is the first step toward a population pharmacokinetic study, including more data to develop a predictable model to be used during therapeutic drug monitoring.

Relationship between hyperglycemia, hormone disturbances, and clinical evolution in severely hyperglycemic post surgery critically ill children: an observational study.

BACKGROUND: To study hormonal changes associated with severe hyperglycemia in critically ill children and the relationship with prognosis and length of stay in intensive care. METHODS: Observational study in twenty-nine critically ill children with severe hyperglycemia defined as 2 blood glucose measurements greater than 180 mg/dL. Severity of illness was assessed using pediatric index of mortality (PIM2), pediatric risk of mortality (PRISM) score, and pediatric logistic organ dysfunction (PELOD) scales. Blood glucose, glycosuria, insulin, C-peptide, cortisol, corticotropin, insulinlike growth factor-1, growth hormone, thyrotropin, thyroxine, and treatment with insulin were recorded. ß-cell function and insulin sensitivity and resistance were determined on the basis of the homeostatic model assessment (HOMA), using blood glucose and C-peptide levels. RESULTS: The initial blood glucose level was 249 mg/dL and fell gradually to 125 mg/dL at 72 hours. Initial ß-cell function (49.2%) and insulin sensitivity (13.2%) were low. At the time of diagnosis of hyperglycemia, 50% of the patients presented insulin resistance and ß-cell dysfunction, 46% presented isolated insulin resistance, and 4% isolated ß-cell dysfunction. ß-cell function improved rapidly but insulin resistance persisted. Initial glycemia did not correlate with any other factor, and there was no relationship between glycemia and mortality. Patients who died had higher cortisol and growth hormone levels at diagnosis. Length of stay was correlated by univariate analysis, but not by multivariate analysis, with C-peptide and glycemic control at 24 hours, insulin resistance, and severity of illness scores. CONCLUSIONS: Critically ill children with severe hyperglycemia initially present decreased ß-cell function and insulin sensitivity. Nonsurvivors had higher cortisol and growth hormone levels and developed hyperglycemia later than survivors.

Adrenaline, terlipressin, and corticoids versus adrenaline in the treatment of experimental pediatric asphyxial cardiac arrest.

OBJECTIVE: To analyze if treatment with adrenaline (epinephrine) plus terlipressin plus corticoids achieves higher return of spontaneous circulation than adrenaline in an experimental infant animal model of asphyxial cardiac arrest. DESIGN: Prospective randomized animal study. SETTING: Experimental department in a University Hospital. SUBJECTS: Forty-nine piglets were studied. INTERVENTIONS: Cardiac arrest was induced by at least 10 minutes of removal of mechanical ventilation and was followed by manual external chest compressions and mechanical ventilation. After 3 minutes of resuscitation, piglets that did not achieve return of spontaneous circulation were randomized to two groups: adrenaline 0.02 mg kg every 3 minutes (20 animals) and adrenaline 0.02 mg kg every 3 minutes plus terlipressin 20 µg kg every 6 minutes plus hydrocortisone 30 mg kg one dose (22 animals). Resuscitation was discontinued when return of spontaneous circulation was achieved or after 24 minutes. MEASUREMENT AND MAIN RESULTS: Return of spontaneous circulation was achieved in 14 piglets (28.5%), 14.2% with only cardiac massage and ventilation. Return of spontaneous circulation was achieved in 25% of piglets treated with adrenaline and in 9.1% of those treated with adrenaline plus terlipressin plus hydrocortisone (p = 0.167). Return of spontaneous circulation was achieved in 45.4% of animals with pulseless electric activity, 20% with asystole, and 0% with ventricular fibrillation (p = 0.037). Shorter duration of cardiac arrest, higher mean blood pressure and EtCO2 and lower PaCO2 before resuscitation, and higher mean blood pressure during resuscitation were associated with higher return of spontaneous circulation. CONCLUSIONS: Treatment with adrenaline plus terlipressin plus corticoids does not achieve higher return of spontaneous circulation than that with adrenaline in an infant animal model of asphyxial cardiac arrest.

0.5 mg/kg versus 1 mg/kg of intravenous omeprazole for the prophylaxis of gastrointestinal bleeding in critically ill children: a randomized study.

OBJECTIVE: To compare the effect of 2 doses of intravenous omeprazole on gastric pH, gastrointestinal bleeding, and adverse effects in critically ill children. STUDY DESIGN: We undertook a prospective randomized clinical trial in critically ill children at risk of gastrointestinal bleeding. The effect of 2 intravenous omeprazole regimens (0.5 or 1 mg/kg every 12 hours) on the gastric pH and incidence of gastrointestinal hemorrhage was compared. The efficacy criteria were a gastric pH >4 and the absence of clinically significant gastrointestinal bleeding. RESULTS: Forty patients, 20 in each treatment group, were studied. Overall, the gastric pH was greater than 4 for 57.8% of the time, with no difference between the doses (P = .66). The percentage of time with a gastric pH > 4 increased during the study (47.8% between 0 and 24 hours vs 76% between 24 and 48 hours, P = .001); the greater dose showed a greater increase in the percentage of time with a pH > 4: between hours 24 and 48 of the study, the gastric pH was greater than 4 for 84.5% of the time with the 1 mg/kg dose and for 65.5% of the time with the 0.5 mg/kg dose (P = .036). Plasma omeprazole levels were greater with 1 mg/kg dose, but no correlation was found between omeprazole plasma levels and gastric pH. No toxic adverse effects were detected, and there was no clinically significant bleeding. CONCLUSION: Neither of the 2 omeprazole regimens achieved adequate alkalinization of the gastric pH during the first 24 hours. Between 24 and 48 hours, the 1 mg/kg dose maintained the gastric pH greater than 4 for a greater percentage of the time.

Protocol for treatment of constipation with polyethylene glycol 3350 plus electrolytes in critically ill children.

INTRODUCTION AND OBJECTIVES: No studies have analysed the effectiveness of treatment for constipation in critically ill children. The aim of this study was to assess the implementation, efficacy and safety of a treatment protocol using polyethylene glycol 3350 with electrolytes (PEG 3350 + E) for constipation in critically ill children. METHODS: We conducted a single-centre prospective study in children admitted to the paediatric intensive care unit for a minimum of 72 h and who developed constipation. Children with previous gastrointestinal disorders or diseases were excluded. The patients were treated with rectal enemas or with the oral PEG 3350 + E protocol at the discretion of the treating physician. We compared clinical and demographic variables as well as adverse events (diarrhoea, abdominal distension and electrolyte imbalances). RESULTS: The sample included 56 patients with a mean age of 48.2 ±â€¯11.9 months, of who 55.4% were male. Forty-four patients (78.6%) were treated with PEG 3350 + E and 12 (21.4%) with rectal enemas. The proportion of patients that responded well to treatment was greater in the PEG 3350 + E group (79.5%) compared to the enema group (58.3%), but the difference was not statistically significant (P = .151). There were no significant differences between the groups in any of the adverse effects. Treatment with PEG 3350 + E was more effective in children aged less than 2 years (100%) compared to older children (100% vs 65.4%; P < .01), with no significant differences in the development of adverse events. CONCLUSIONS: The PEG 3350 + E treatment protocol for constipation in critically ill children was effective and associated with few adverse events, even in children aged less than 2 years.

Volumetric capnography and return of spontaneous circulation in an experimental model of pediatric asphyxial cardiac arrest.

A secondary analysis of a randomized study was performed to study the relationship between volumetric capnography (VCAP) and arterial CO2 partial pressure (PCO2) during cardiopulmonary resuscitation (CPR) and to analyze the ability of these parameters to predict the return of spontaneous circulation (ROSC) in a pediatric animal model of asphyxial cardiac arrest (CA). Asphyxial CA was induced by sedation, muscle relaxation and extubation. CPR was started 2 min after CA occurred. Airway management was performed with early endotracheal intubation or bag-mask ventilation, according to randomization group. CPR was continued until ROSC or 24 min of resuscitation. End-tidal carbon dioxide (EtCO2), CO2 production (VCO2), and EtCO2/VCO2/kg ratio were continuously recorded. Seventy-nine piglets were included, 26 (32.9%) of whom achieved ROSC. EtCO2 was the best predictor of ROSC (AUC 0.72, p < 0.01 and optimal cutoff point of 21.6 mmHg). No statistical differences were obtained regarding VCO2, VCO2/kg and EtCO2/VCO2/kg ratios. VCO2 and VCO2/kg showed an inverse correlation with PCO2, with a higher correlation coefficient as resuscitation progressed. EtCO2 also had an inverse correlation with PCO2 from minute 18 to 24 of resuscitation. Our findings suggest that EtCO2 is the best VCAP-derived parameter for predicting ROSC. EtCO2 and VCO2 showed an inverse correlation with PCO2. Therefore, these parameters are not adequate to measure ventilation during CPR.

High-flow oxygen therapy: pressure analysis in a pediatric airway model.

BACKGROUND: The mechanism of high-flow oxygen therapy and the pressures reached in the airway have not been defined. We hypothesized that the flow would generate a low continuous positive pressure, and that elevated flow rates in this model could produce moderate pressures. The objective of this study was to analyze the pressure generated by a high-flow oxygen therapy system in an experimental model of the pediatric airway. METHODS: An experimental in vitro study was performed. A high-flow oxygen therapy system was connected to 3 types of interface (nasal cannulae, nasal mask, and oronasal mask) and applied to 2 types of pediatric manikin (infant and neonatal). The pressures generated in the circuit, in the airway, and in the pharynx were measured at different flow rates (5, 10, 15, and 20 L/min). The experiment was conducted with and without a leak (mouth sealed and unsealed). Linear regression analyses were performed for each set of measurements. RESULTS: The pressures generated with the different interfaces were very similar. The maximum pressure recorded was 4 cm H(2)O with a flow of 20 L/min via nasal cannulae or nasal mask. When the mouth of the manikin was held open, the pressures reached in the airway and pharynxes were undetectable. Linear regression analyses showed a similar linear relationship between flow and pressures measured in the pharynx (pressure = -0.375 + 0.138 × flow) and in the airway (pressure = -0.375 + 0.158 × flow) with the closed mouth condition. CONCLUSIONS: According to our hypothesis, high-flow oxygen therapy systems produced a low-level CPAP in an experimental pediatric model, even with the use of very high flow rates. Linear regression analyses showed similar linear relationships between flow and pressures measured in the pharynx and in the airway. This finding suggests that, at least in part, the effects may be due to other mechanisms.

Enteral nutrition in the critically ill child: comparison of standard and protein-enriched diets.

OBJECTIVE: To compare a standard diet and a protein-enriched diet in critically ill children. STUDY DESIGN: In this prospective randomized controlled trial in critically ill children, all patients received enteral nutrition exclusively and were randomly assigned to a standard diet or a protein-enriched diet (1.1 g protein/100 mL of feeding formula). Blood and urine tests, nitrogen balance assessment, and energy expenditure testing by indirect calorimetry were performed before the beginning of the nutrition regimen and at 24 hours, 72 hours, and 5 days after initiation. Demographic data and pediatric mortality risk scores were recorded. RESULTS: Fifty-one children were randomized, and 41 completed the study. Of these, 21 patients received standard formula and 20 received a protein-enriched formula. There were no between-group differences in terms age, sex, diagnosis, or mortality risk scores. There was a greater positive trend in levels of prealbumin, transferrin, retinol-binding protein, and total protein in the protein-enriched diet group. These differences were significant only for retinol-binding protein. The positive nitrogen balance trend was also higher in the protein-enriched diet group; however, this difference did not reach statistical significance. No adverse effects or hyperproteinemia were detected in the protein-enriched diet group. CONCLUSIONS: The standard diet provides insufficient protein delivery to critically ill children. Enteral protein supplementation is safe and can improve some biochemical parameters of protein metabolism.

Relationship between energy expenditure, nutritional status and clinical severity before starting enteral nutrition in critically ill children.

The objective of the present study was to investigate the relationship between energy expenditure (EE), biochemical and anthropometric nutritional status and severity scales in critically ill children. We performed a prospective observational study in forty-six critically ill children. The following variables were recorded before starting nutrition: age, sex, diagnosis, weight, height, risk of mortality according to the Paediatric Risk Score of Mortality (PRISM), the Revised Paediatric Index of Mortality (PIM2) and the Paediatric Logistic Organ Dysfunction (PELOD) scales, laboratory parameters (albumin, total proteins, prealbumin, transferrin, retinol-binding protein, cholesterol and TAG, and nitrogen balance) and EE measured by indirect calorimetry. The results showed that there was no relationship between EE and clinical severity evaluated using the PRISM, PIM2 and PELOD scales or with the anthropometric nutritional status or biochemical alterations. Finally, it was concluded that neither nutritional status nor clinical severity is related to EE. Therefore, EE must be measured individually in each critically ill child using indirect calorimetry.