Mechanical Ventilation In Pediatric Patients Research Articles

Predictors of Prolonged Mechanical Ventilation in Pediatric Patients with Hemolytic Uremic Syndrome

AbstractThis study aimed to analyze factors associated with mechanical ventilation (MV) and prolonged MV (≥12 days) in pediatric hemolytic uremic syndrome (HUS) patients. Retrospective multicenter cohort study analyzed data from 3,831 pediatric HUS (age <18 years) patients between 2004 and 2018 from Pediatric Health Information System database. Multivariate logistic regression was used to pinpoint factors associated with MV and prolonged MV. Among 3,831 patients analyzed, 769 (20%) patients required MV, 166 (23.6%) of them were prolonged MV. Factors independently associated with prolonged MV include African American (adjusted odds ratio [aOR]: 1.98, 95% confidence interval [CI]: 1.11–3.54, p = 0.02), children aged between 1 and 5 years (aOR: 7.69, 95% CI: 3.71–15.93, p < 0.001), pneumonia (aOR: 2.54, 95% CI: 1.51–4.25, p < 0.001), pneumothorax (aOR: 2.41, 95% CI: 1.08–5.39, p = 0.032), liver dysfunction (aOR: 3.22, 95% CI: 1.68–6.16, p < 0.001), ileus with perforation (aOR: 1.83, 95% CI: 1.03–3.25, p = 0.039), and sepsis (aOR: 1.97, 95% CI: 1.26–3.08, p = 0.003). In pediatric HUS cases, 20% required MV, and 23.6% of them were prolonged MV. Factors associated with prolong MV include African American race, children aged between 1 and 5 years, pneumonia, pneumothorax, liver dysfunction, ileus with perforation, and sepsis.

Factors Associated With Mechanical Ventilation Duration in Pediatric Burn Patients in a Regional Burn Center in the United States.

Among burned children who arrive at a burn center and require invasive mechanical ventilation (IMV), some may have prolonged IMV needs. This has implications for patient-centered outcomes as well as triage and resource allocation decisions. Our objective was to identify factors associated with the duration of mechanical ventilation in pediatric patients with acute burn injury in this setting. Single-center, retrospective cohort study. Registry data from a regional, pediatric burn center in the United States. Children less than or equal to 18 years old admitted with acute burn injury who received IMV between January 2005 and December 2020. None. Ventilator days were defined as any full or partial day having received IMV via an endotracheal tube or tracheostomy, not inclusive of time spent ventilated for procedures. Of 5,766 admissions for acute burn care, 4.3% ( n = 249) required IMV with a median duration of 10 days. A multivariable model for freedom from mechanical ventilation showed that the presence of inhalational injury (subhazard ratio [sHR], 0.62; 95% CI, 0.46-0.85) and burns to the head and neck region (sHR, 0.94; 95% CI, 0.90-0.98) were associated with increased risk of remaining mechanically ventilated at any time point. Older (sHR, 1.03; 95% CI, 1.01-1.04) and male children (sHR, 1.39; 95% CI, 1.05-1.84) were more likely to discontinue mechanical ventilation. A majority of children (94.8%) survived to hospital discharge. The presence of inhalational injury and burns to the head and neck region were associated with a longer duration of mechanical ventilation. Older age and male gender were associated with a shorter duration of mechanical ventilation. These factors should help clinicians better estimate a burned child's expected trajectory and resource-intensive needs upon arrival to a burn center.

Incidence of Mechanical Ventilation Adverse Events in Critically Ill Children in a Tertiary Pediatric Intensive Care Unit.

OBJECTIVE:Despite the clinical use of mechanical ventilation having well-documented benefits, it can be associated with complications and adverse physiological effects that can impact mortality rates. There are few studies that examine complications associated with mechanical ventilation in children and the factors associated with complications in detail. This study aimed to investigate adverse events associated with mechanical ventilation in pediatric patients and to compare the epidemiology of complications associated with mechanical ventilation. MATERIAL AND METHODS:The medical records of patients in a tertiary care pediatric intensive care unit who were mechanically ventilated between January 1, 2013, and July 31, 2017, were evaluated. Results:A total of 187 patients were included in the study, 105 boys (56.1%) and 82 girls (43.9%), and 45 (24.1%) patients experienced complications. The total number of mechanical ventilation days was 1100. Atelectasis (12.3%), post-extubation stridor (8.5%), ventilator-associated pneumonia (5.4%), and pneumothorax (5.4%) were most commonly observed complications. Conclusion:Complications of mechanical ventilation in the pediatric population still occur frequently. In this study, the incidence of atelectasis was high, and also, incidences of ventilator-associated pneumonia and pneumothorax were low.

Diaphragm and Lung Ultrasound Indices in Prediction of Outcome of Weaning from Mechanical Ventilation in Pediatric Intensive Care Unit.

ObjectiveTo predict the added value of diaphragmatic and lung ultrasound indices (US) in anticipation of the outcome of mechanical ventilation of pediatric patients in the intensive care unit.MethodsThis prospective study was conducted in Zagazig University, Pediatric Hospitals, PICU; Egypt. One hundred six mechanically ventilated children aged between 1 mo to 170 mo were included in the study. All patients were candidates for weaning and have been given a chance for spontaneous breathing trial (SBT), during which diaphragmatic and lung US was performed for them. The diaphragm thickening fraction (DTF), the diaphragmatic excursion and the lung US score (LUS), that included 4 US aeration forms, were assessed.ResultsThere were statistically significant differences between patients with failed weaning and those with successful weaning regarding DTF, diaphragmatic excursion and LUS (p < 0.001). The best cut-off value of DTF, diaphragmatic excursion, and LUS for predicting weaning failure was ≥23.175%, ≥ 6.2 mm, and ≥ 12 with an AUC (area under curve) of 0.932, 0.876, and 0.934, respectively.ConclusionsDiaphragmatic and lung US add a quick, accurate and non-invasive indices to the weaning readiness parameters compared to the other standard parameters alone. So, it is recommended to be added to the predictive parameters of weaning outcome.

Dexmedetomidine facilitates extubation in children who require intubation and respiratory support after airway foreign body retrieval: a case-cohort analysis of 57 cases.

This study aimed to investigate whether dexmedetomidine had sedative weaning advantage for extubation after airway foreign body (FB) removal in children. A retrospective case-cohort comparison study with total of 57 critical children who required mechanical ventilation after rigid bronchoscopy was performed. After tracheal intubation, group D (received dexmedetomidine 1µg/kg over 10min, followed by an infusion of 0.8µg/kg/h), and group RP (received remifentanil-propofol 6-10µg/kg/h and 1-3mg/kg/h, respectively). The primary outcome was successful extubation rate on first weaning trial. The minor outcomes included weaning time, emergency agitation, coughing score and the incidence of respiratory adverse complications on emergency. All 57 patients were included in the analysis, with 30 patients in group D and 27 controlled cases in group RP. The success rate of first weaning trial in the D group was 96.7 vs 77.8% in the RP group, risk ratio (RR) 1.56, 95% CI [0.78-1.98]. Time for resuming spontaneous breathing after termination infusion was shorter in the D group (median 8min, IQR 15min) vs RP group (median 12min, IQR 19min, P = 0.02, RR 0.56, 95% CI 0.14-6.57). In mechanical ventilation of pediatric patients following rigid bronchoscopy, in comparison to remifentanil-propofol, dexmedetomidine is proved to have high success rate for weaning strategy. WHAT IS ALREADY KNOWN?: Remifentanil is proved to be effective for weaning in ICU patients. Dexmedetomedine can provide similar rates of smooth extubation for pediatric patients who underwent airway surgery. WHAT THIS ARTICLE ADDS?: Invasive ventilation is used for patients with severe comorbidity after airway surgery, but the correct strategy for pediatric extubation after removal of airway foreign body remains unclear. For these patients with short-term mechanical ventilation, dexmedetomedine may improve the extubation rate, when compared with remifentanil-propofol.

Risk factors and outcomes of tracheostomy after prolonged mechanical ventilation in pediatric patients with heart disease

The indications for tracheostomy after prolonged mechanical ventilation among pediatric patients with heart disease are multifactorial and difficult to determine; therefore, knowing the risk factors and outcomes of tracheostomy may be useful for selecting patients who require tracheostomy. The aim of this study was to identify the risk factors and outcomes of tracheostomy after prolonged mechanical ventilation in pediatric patients with heart disease. We performed a retrospective, single-center observational study in consecutive patients with heart disease aged ≤18 years admitted to a pediatric intensive care unit at a tertiary children's hospital between January 2010 and December 2016. Patients who required prolonged mechanical ventilation (≥14 days) were included. Clinical characteristics and outcomes were compared between the patients with and without tracheostomy and the risk factors for receiving tracheostomy were assessed. Of the 85 patients who required prolonged mechanical ventilation, 20 (24%) underwent tracheostomy. The duration of mechanical ventilation before tracheostomy was 51 days, and pediatric intensive care unit lengths of stay in patients with and without tracheostomy were 83 and 34 days, respectively (P < 0.001). Risk factors for tracheostomy were multiple (≥2) surgeries and mean airway pressure ≥ 10 cmH2O after 14 days of mechanical ventilation. In patients with tracheostomy, six (30%) were successfully weaned from mechanical ventilation and two (10%) were de-cannulated. Tracheostomy complications included granulation tissue in three cases and airway obstruction in one. There was no difference in the survival rates of patients with and without tracheostomy (70% vs. 74%; P = 0.73). Although the mortality rate of patients with and those without tracheostomy were not significantly different, the baseline illness severity might be different. Further studies that adjust for patient factors, such as disease severity, are needed to determine the effect of tracheostomy on patient outcomes; however, this was beyond the scope of our study.

Mapleson D continuous positive airway pressure system for weaning of mechanical ventilation in pediatric patients.

Mapleson D continuous positive airway pressure system for weaning of mechanical ventilation in pediatric patients.

Mapleson D continuous positive airway pressure system for weaning of mechanical ventilation in pediatric patients: In response.

Mapleson D continuous positive airway pressure system for weaning of mechanical ventilation in pediatric patients: In response.

Predictors of Prolonged Mechanical Ventilation in Pediatric Patients After Cardiac Surgery for Congenital Heart Disease.

BackgroundThe duration of mechanical ventilation (MV) is one of the most important clinical factors which predict outcomes in pediatric cardiac surgery. The prolonged mechanical ventilation (PMV) following cardiac surgery is a multifactorial phenomenon and there are conflicts regarding its predictors in pediatric population between different centers.ObjectivesThe current study aimed to describe PMV predictors in patients undergoing cardiac surgery for congenital heart disease in a tertiary center for pediatric cardiovascular diseases in Iran.Patients and MethodsFrom May to December 2014, all pediatric patients (less than a month – 15 years old) admitted to pediatric Intensive Care Unit (PICU) after congenital heart surgeries were consecutively included. The PMV was defined as mechanical ventilation duration more than 72 hours as medium PMV and more than seven days as extended PMV. The demographic data and variables probably related to PMV were recorded during the PICU stay.ResultsA total of 300 patients, 56.7% male, were enrolled in this study. Their mean age was 32 ± 40 months .The median duration (IQR) of MV was 18 hours (8.6 - 48 hours). The incidence of PMV more than 72 hours and seven days was 20% and 10.7%, respectively. Younger age, lower weight, heart failure, higher doses of inotropes, pulmonary hypertension, respiratory infections and delayed sternal closure were independent predictors of PMV in multivariate analyses.ConclusionsThe results of this study indicated that PMV predictors could be specific for each center and a good administration program is needed for each pediatric cardiac surgery center for the preoperative management of patients undergoing congenital heart surgeries.

Is the Pressure Control Mode for Pediatric Anesthesia Machines Really Required?

Dear Editor, Choosing an appropriate anesthesia machine for mechanical ventilation of pediatric patients is of paramount importance because small changes in the fractions of the delivered tidal volume can cause a significant difference from the desired tidal volume. The anesthesia machines have classically been divided up into pressure or volume controlled modes, with two main characteristics; the limit (what determines the size of the breath), and the cycle (what actually ends the breath). The traditional anesthesia machines with volume controlled mode are not able to deliver precisely small tidal volumes to the pediatric patients. In the traditional anesthesia machines, fresh gas directly streams to the breathing circuit, so if 6 L/min of fresh gas is added to the previous setting (6 liters/60 seconds) 100 mL/s will be added to the delivered tidal volume, and if the inspiratory time is 2 seconds, 200 mL will be added to the tidal volume. These differences significantly increase the desired tidal volume. Therefore, the conventional anesthesia machines with the volume-controlled ventilation mode are not suitable to deliver a tidal volume less than 200 mL. During ventilation of neonates or children (in which tidal volume is less than 200 cc, respiratory rate is at least 16 - 20/minute and with a 1:2 I/E ratio, inspiratory time is less than 1 second), these differences are not acceptable. Thus, anesthesiologists usually use pressure-controlled ventilation rather than volume-controlled ventilation for pediatric anesthesia. A pressure-limited, time-cycled pulmonary ventilator includes a pressurized gas system that supplies respiratory gas to a patient at a selected inspiratory flow rate; an exhalation valve that opens an expiratory flow path in response to the elapsing of a selected inspiratory time period, and maintains a selected proximal pressure limit during the inspiratory time period. The tidal volume that results from a pressure-targeted machine is attributable to the set inspiratory pressure and patient’s lung-thorax compliance. Circuit compliance, fresh gas flow changes, and even small leaks around an un-cuffed endotracheal tube do not modify the delivered tidal volume (1). Pressure-controlled ventilation offers the advantage of limiting barotrauma in the condition of changing lung compliance, but a decrease in tidal volume will occur in the pressure-controlled ventilation mode, when the compliance of the lung is decreased or a pressure against the abdomen is created (e.g. in laparoscopic surgeries) (2). There are also some pediatric ventilators that deliver the breath by setting the inspiratory and expiratory duration and setting the flow of gas, but management of patients with these ventilators can lead to hypoventilation in the circumstance of increasing of the pulmonary resistance or reversal of muscle relaxants. To deliver a precise tidal volume, some new anesthesia machines have equipped with fresh gas decoupling valves. In these machines, the fresh gas (FGF) is not delivered to the inspiratory limb during inspiration. Practically, it means that FGF does not increase the tidal volume. The function of the fresh gas decoupling valve is to provide a precise delivery of the set tidal volume unaffected by varying fresh gas flow rates. During the inspiratory phase of ventilation, the valve closes, allowing only gas from the ventilator piston chamber to be delivered through the inspiratory branch to the patient. During the expiratory phase, the valve opens, allowing the ventilator piston chamber to fill with a mixture of the exhaled gas that has passed through the absorber and fresh gas (3). A second method for accurate delivery of desired tidal volume is compliance compensation, to replace volume lost to the breathing tubes. A potentially large percentage of the bellows volume is lost into the breathing circuit, secondary to compliance and compression. Leaks and sampled gas flow will further reduce desired tidal volume (4). To ensure that the set tidal volume will be delivered to the patients, new anesthesia machines involve a preuse leak and compliance test during which the end of the circuit must be occluded. The total compliance will be measured and the machine use this data to adjust piston or bellows movement, according to desired pressure airway setting (5). The anesthesiologist can use volume-controlled ventilation by a modern anesthesia machine that equipped with fresh gas decoupling valves and compliance and fresh gas compensation technology with confidence. Minimal tidal volume as low as 30 mL can be delivered precisely (5). The anesthesiologist should not persist in ordering a ventilator with multiple ventilation modes. Rather, choosing a ventilator with a unique mode that delivers a precise tidal volume would be suitable.

Predictors of prolonged mechanical ventilation in pediatric patients after cardiac surgery for congenital heart disease

Background: The duration of mechanical ventilation (MV) is one of the most important clinical factors which predict outcomes in pediatric cardiac surgery. The prolonged mechanical ventilation (PMV) following cardiac surgery is a multifactorial phenomenon and there are conflicts regarding its predictors in pediatric population between different centers. Objectives: The current study aimed to describe PMVpredictors in patients undergoing cardiac surgery for congenital heart disease in a tertiary center for pediatric cardiovascular diseases in Iran. Patients and Methods: From May to December 2014, all pediatric patients (less than a month -15 years old) admitted to pediatric Intensive Care Unit (PICU) after congenital heart surgeries were consecutively included. The PMV was defined as mechanical ventila- tion duration more than 72 hours as medium PMV and more than seven days as extended PMV. The demographic data and variables probably related to PMV were recorded during the PICU stay. Results: A total of 300 patients, 56.7% male, were enrolled in this study. Their mean age was 32 ± 40 months .The median duration (IQR) of MVwas 18 hours (8.6 - 48 hours). The incidence of PMV more than 72 hours and seven days was 20% and 10.7%, respectively. Younger age, lower weight, heart failure, higher doses of inotropes, pulmonary hypertension, respiratory infections and delayed sternal closure were independent predictors of PMV in multivariate analyses. Conclusions: The results of this study indicated that PMV predictors could be specific for each center and a good administration program is needed for each pediatric cardiac surgery center for the preoperative management of patients undergoing congenital heart surgeries.

Evaluation of a Mapleson D CPAP system for weaning of mechanical ventilation in pediatric patients.

Background:Over the last years, we have used a flow-inflating bag circuit with a nasotracheal or nasopharyngeal tube as an interface to deliver effective CPAP support in infants (“Mapleson D CPAP system”). The primary goal of this study was to assess the usefulness of the “Mapleson D CPAP system” for weaning of mechanical ventilation (MV) in infants who received MV over 24 h.Materials and Methods:All infants who received MV for more than 24 h in the last year were enrolled in the study. Demographic data included age, gender, weight, and admission diagnosis. Heart rate, respiratory rate, blood pressure, and oxygen saturation were measured during MV, 2 h after the nasotracheal Mapleson D CPAP system and 2 h after extubation. Patients were classified into two groups: patients MV more than 48 h, and patients with MV fewer than 48 h. P < 0.05 was considered statistically significant.Results:A total of 50 children were enrolled in the study, with a median age was 34 ± 45 months (range, 1–59 months) and median weight was 11.98 ± 9.31 kg (range, 1–48 kg). Median duration of MV was 480 h (range, 2–570). There were no significant differences in PaO2, PaCO2, and pH among MV, 2 h after the nasotracheal Mapleson D CPAP system and 2 h after extubation and spontaneous ventilation with the nasopharyngeal Mapleson D CPAP system or with nasal prongs. The overall extubation failure rate was 26% (n = 13). Weight and age were significantly associated with extubation failure (P < 0.05).Conclusions:The Mapleson D CPAP system, in our opinion, is a useful and safe alternative to more complex and expensive noninvasive CPAP and BiPAP weaning from MV in infants.

The pressure drop across the endotracheal tube in mechanically ventilated pediatric patients.

During mechanical ventilation, the airway pressure (Paw) is usually monitored. However, Paw comprises the endotracheal tube (ETT)-related pressure drop (∆PETT ) and thus does not reflect the pressure in the patients' lungs. Therefore, monitoring of mechanical ventilation should be based on the tracheal pressure (Ptrach ). We systematically investigated potential factors influencing ∆PETT in pediatric ETTs. In this study, the flow-dependent pressure drop across pediatric ETTs from four manufacturers [2.0-4.5 mm inner diameter (ID)] was estimated in a physical model of the upper airways. Additionally, ∆PETT was examined with the ETTs shortened to 75% of their original length and at different curvatures. In nine healthy mechanically ventilated children (aged between 9 days and 29 months), Ptrach was compared to Paw . ∆PETT was nonlinearly flow dependent. Low IDs corresponded to high ∆PETT . Differences between ETTs from different manufacturers were identified. Shortening of the ETTs' length by 25% reduced ∆PETT on average by 14% of the value at original length. Ventilation frequency and tube curvature did not influence ∆PETT to a relevant extent. In the pediatric patients, the root mean square deviation between Paw and Ptrach was 2.3 cm H2O. Paw and Ptrach differ considerably (by ∆PETT ) during mechanical ventilation of pediatric patients. The ETTs' ID, tube length, and manufacturer type are significant factors for ∆PETT and should be taken into account when Paw is valuated. For this purpose, Ptrach can be continuously calculated with good precision by means of the Rohrer approximation.

Multicenter Randomized Controlled Trial of Inhaled Nitric Oxide for Pediatric Acute Respiratory Distress Syndrome

To test the hypothesis that inhaled nitric oxide (iNO) would lead to improved oxygenation and a decrease in duration of mechanical ventilation in pediatric patients with acute respiratory distress syndrome. A total of 55 children with acute respiratory distress syndrome were enrolled from 9 centers. Patients were randomized to iNO or placebo and remained on the study drug until death, they were free of ventilator support, or day 28 after the initiation of therapy. Mean baseline oxygenation indexes (OIs) were 22.0 ± 18.4 and 25.6 ± 14.9 (iNO and placebo groups, respectively, P = .27). There was a trend toward an improved OI in the iNO group compared with the placebo group at 4 hours that became significant at 12 hours. There was no difference in the OI between groups at 24 hours. Days alive and ventilator free at 28 days was greater in the iNO group, 14.2 ± 8.1 and 9.1 ± 9.5 days (iNO and placebo groups, respectively, P = .05). Although overall survival at 28 days failed to reach statistical significance, 92% (22 of 24) in the iNO group and 72% (21 of 29) in the placebo group (P = .07), the rate of extracorporeal membrane oxygenation-free survival was significantly greater in those randomized to iNO 92% (22 of 24) vs 52% (15 of 29) for those receiving placebo (P < .01). The use of iNO was associated with a significantly reduced duration of mechanical ventilation and significantly greater rate of extracorporeal membrane oxygenation-free survival.

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Introduction: Mortality in pediatric patients with acute respiratory distress syndrome (ARDS) remains high despite improvements in care of these children. Inhaled nitric oxide (iNO) is a potent vasodilator that is delivered directly to areas of the ventilated lung to improve ventilation/perfusion mismatch resulting in improved oxygenation, and relieving pulmonary hypertension resulting from regional hypoxia. Recent studies have shown that the combined treatment of high frequency oscillatory ventilation and iNO improve oxygenation in children with ARDS. This implies the potential role of lung recruitment when used in conjunction with iNO to improve oxygenation. No study has examined the relationship of lung recruitment and effectiveness of iNO during conventional mechanical ventilation in pediatric patients. Methods: Young pigs (~10 kg) underwent lung injury with saline washout and ventilator-induced injury (20 ml/kg tidal volume, without peep). Lung injury was confirmed by PaO2/FiO2 ratio <200 and a decrease in the static compliance by 50% decrease from baseline. The piglets were then ventilated in a pressure control mode with the peak inspiratory pressures adjusted to achieve a tidal volume of 6 ml/kg. The FiO2 was kept at 1. A pulmonary artery (PA) catheter was placed for PA pressure monitoring and mixed venous saturation measurement. Inhaled NO was administered before and after lung recruitment at 5, 10 and 20 ppm concentrations. Lung recruitment was confirmed by measuring the static compliance and by the sum of PaO2+PaCO2 >= 400 mmHg. Arterial blood gas, mixed venous blood gas, lung compliance, hemodynamic parameters and methemoglobin levels were obtained at each iNO concentration after ventilating for 15 min. Each animal underwent section to evaluate gross pathology of lung injury and position of PA catheter. Results: The change in PaO2 level in recruited lungs was significantly higher than in non-recruited lungs at 5 and 20 ppm of iNO (5 ppm: delta PaO2 24 mmHg +/- 14 mmHg vs. 62 mmHg +/- 26 mmHg, p value 0.016; 20 ppm: delta PaO2 21 mmHg +/- 30 mmHg vs 67 mmHg +/- 29 mmHg, p value 0.039). There was no significance in the PaO2 response in non-recruited lungs vs. recruited lungs at an iNO concentration of 10 ppm. Methemoglobin levels, mixed venous saturations, and mean pulmonary artery pressures did not differ significantly at each iNO level in the recruited vs non-recruited lungs. Pearson correlation index for PaO2 in response to iNO and static compliance was ~0.18. Conclusions: Lung recruitment improves the response to iNO significantly at concentrations of 5 ppm and 20 ppm. During conventional mechanical ventilation, static compliance may be used as a predictor of iNO efficacy.

Role of ketamine in refractory status asthmaticus: A case report

Patients experiencing severe asthma exacerbations occasionally deteriorate to respiratory failure requiring endotracheal intubation and mechanical ventilation. Mechanical ventilation in this setting exposes the patients to substantial iatrogenic risk and should be avoided if at all possible. This case suggests that intravenous ketamine given in a dissociative dose may be an effective measure to avoid mechanical ventilation in pediatric patients with severe asthma exacerbations.

Heat and Moisture Exchangers and Humidification Efficacy in Pediatrics: Effects of Ventilator Settings and ETT Leakage

Heat and moisture exchangers (HMEs) have been increasingly used for humidification during mechanical ventilation in pediatric patients [1]. However, efficacy of HMEs in the pediatric population has not yet been fully evaluated and there is limited information in the literature regarding the effects of ventilator settings and endotracheal tube (ETT) leakage on the humidification performance of HMEs. Chikata et al. [2] tested ten pediatric HMEs in a model lung, measuring performance under different respiratory rates, tidal volumes TVs (achieved with different pressure control levels), and leakage conditions. They found that eight of the ten HMEs maintained absolute humidity (AH) at more than 30 mg/L, the minimum level recommended by the American Association for Respiratory Care (AARC). With a small leak, AH decreased below 30 mg/L (26.6 to 29.5 mg/L), decreasing further (19.7 to 27.3 mg/L) with a larger leak. Pressure control (tidal volume) level did not statistically significantly affect AH values, although there was a trend to decreased AH at higher tidal volumes. In three of the HMEs, increased respiratory rate resulted in a significantly higher AH. In six of the other seven HMEs, there was a nonstatistically significant trend to higher AH with increased respiratory rate, with one HME showing a nonsignificant trend to lower AH. We think this is a well-designed and conducted study and provides valuable information regarding the use of HMEs in pediatric patients under different conditions. The effect of ETT leakage on AH is nicely demonstrated and is consistent with previously published data on mechanically ventilated adults. However, we had some questions regarding the study's other findings and their possible explanation as follows the study found that 8 out of 10 pediatric HMEs maintained AH at more than 30 mg/L, while they quote the Luchetti et al. [3] study they reference as showing “AH of less than 28 mg/L in all HMEs used with pediatric patients” despite using similar one-way valve methodology in their circuit to prevent mixing of inspired and expired gases? This finding is even more puzzling given that one of the two HMEs used in the Luchetti study, the Hygroboy (Covidien [formerly Tyco Healthcare], Mirandola, Italy), in the present study was found to produce the highest AH (32.4 mg/L) of the ten HMEs tested. How is this difference in findings between the 2 studies of the same HME explained? the finding that increased respiratory rates resulted in a trend to higher AH that reached significance in 3 of the tested humidifiers is interesting. Previous studies of HMEs in adults and children have found lower AH associated with higher tidal volumes [4, 5] and minute volumes (MVs) [1, 6, 7]. It would seem more logical that an increasing respiratory rate presumably would result in a higher MV, with resultant lower AH, but Chikata et al. found the opposite. The authors did not comment on this in their paper, and we wonder if they have a plausible explanation for this; finally, the authors speculate that the finding of a linear relationship between increasing dead space and increasing AH might possibly be related to improved humidification in those HMEs with larger internal volume and dead space. Since it is generally recommended to minimize dead space with HMEs, in particular in pediatric use, would the authors care to comment on striking a balance between maximizing humidification capacity and minimizing dead space?

Positive Fluid Balance Is Associated with Higher Mortality and Prolonged Mechanical Ventilation in Pediatric Patients with Acute Lung Injury

Introduction. We analyzed a database of 320 pediatric patients with acute lung injury (ALI), to test the hypothesis that positive fluid balance is associated with worse clinical outcomes in children with ALI. Methods. This is a post-hoc analysis of previously collected data. Cumulative fluid balance was analyzed in ml per kilogram per day for the first 72 hours after ALI while in the PICU. The primary outcome was mortality; the secondary outcome was ventilator-free days. Results. Positive fluid balance (in increments of 10 mL/kg/24 h) was associated with a significant increase in both mortality and prolonged duration of mechanical ventilation, independent of the presence of multiple organ system failure and the extent of oxygenation defect. These relationships remained unchanged when the subgroup of patients with septic shock (n = 39) were excluded. Conclusions. Persistently positive fluid balance may be deleterious to pediatric patients with ALI. A confirmatory, prospective randomized controlled trial of fluid management in pediatric patients with ALI is warranted.

Measurement of the end-expiratory lung volume without interruption of mechanical ventilation in pediatric patients

Monitoring the end-expiratory lung volume (EELV) is a valuable tool to optimize respiratory settings that could be of particular importance in mechanically ventilated pediatric patients. We evaluated the feasibility and precision of an ICU ventilator with an inbuilt nitrogen washout/washin technique in mechanically ventilated pediatric patients.

Use of mechanical ventilation in pediatric patients

Major aims of mechanical ventilation (MV) in pediatrics mean the contribution to complete recovery of acute disorder or to establishing stability of previously long-term changed health condition. MV is used today in 16-46% of patients treated in pediatric intensive care units. The aim of this paper was to get insight into the presence of the disease and pathologic conditions and outcome of MV regarding previous health condition of pediatric patients. This retrospective study included 476 pediatric patients (beyond neonatal age) who underwent mechanical ventilation (MV). On the basis of previous health status the patients were classified in two groups: the group A consisted of 157 children with no previous chronic disease leading to MV and the group H comprised of 319 children who received MV due to worsening ofprevious chronic disease. In both groups of pediatric patients there was significant predominance of younger age patients. Acute and chronic neurological disorders were the most frequent conditions requiring use of MV. Out of a total number (476) of the patients, 178 patients (37.40%) died. In the group A 17 patients (10.9%) died, while in the group H mortality rate was significantly higher (161 or 50.5% patients died; p < 0.01; RR 4.85; CI 3.1-7.6). Total duration time of MV in all the patients was 7 525 days, with 1 345 days (15%) accounted for the group A and 4 567 days (85%) for the group H. Mean MV duration was 7.48 (+/- 9.23) days for the patients in the group A which is significantly shorter in comparison to mean 21.8 (+/- 57.96) days for the group H patients (p < 0.001). These results point out significant contribution of MV to better outcome in pediatric patients with different acute disorders. Clear dominance of chronically ill children requiring mechanical ventilation due to acute worsening of their condition implies new complexity of problems regarding organization of pediatric intensive care and treatment.