Effect of neuromuscular blockade on oxygen consumption and energy expenditure in sedated, mechanically ventilated children

OBJECTIVE: To quantify the effects of neuromuscular blockade (NMB) on energy expenditure for intubated, mechanically ventilated, critically ill children. DESIGN: A prospective, unblinded clinical study. Each subject was studied twice, before and after establishment of NMB. SETTING: A tertiary care pediatric intensive care unit. PATIENTS: Critically ill children undergoing mechanical ventilation and receiving ongoing sedation were eligible, if they had a cuffed endotracheal tube and were physiologically stable. INTERVENTIONS: A total of 20 children (age, 1 to 15 yrs) were studied in an unblinded, crossover fashion. All were mechanically ventilated via a cuffed endotracheal tube, with ventilator rate and tidal volume adequate to provide complete ventilation, and F(IO2) <0.6. Absence of gas leak around the endotracheal tube was assured, and all patients were sedated using continuous infusions of midazolam and/or fentanyl; no changes in ventilator settings, nutritional input, or inotropic drug dose were permitted during the study period. Each patient underwent indirect calorimetry immediately before establishment of NMB. NMB was then induced, and indirect calorimetry was repeated. Complete blockade was verified using a peripheral nerve stimulator. In each case, the two sets of measurements were completed within a 1-hr period. MEASUREMENTS AND MAIN RESULTS: Data analyzed included identifying and diagnostic information, oxygen consumption, and carbon dioxide production. Energy expenditure was calculated using standard formulas. Oxygen consumption and energy expenditure values obtained before and after the establishment of NMB were compared by using paired Student's t-test. NMB reduced oxygen consumption from 6.54+/-0.49 mL/kg/min to 5.90+/-0.40 ml/kg/min, and energy expenditure was reduced from 46.5+/-3.7 kcal/kg/24 hrs to 41.0+/-2.8 kcal/kg/24 hrs (p < .001 in each case). The reduction in oxygen consumption was 8.7+/-1.7%, and that in energy expenditure 10.3+/-1.8%, of pre-NMB values, respectively. CONCLUSION: NMB significantly reduces oxygen consumption and energy expenditure in critically ill children who are sedated and mechanically ventilated; the degree of reduction is small.     

Skin breakdown in children and high-frequency oscillatory ventilation

Objective: To investigate the relationship of high-frequency oscillatory ventilation (HFOV) to skin breakdown on the scalp and ears in mechanically ventilated children.Study Design: Retrospective cohort study of 32 patients supported with HFOV paired with 32 patients supported with conventional mechanical ventilation (CV) in a pediatric intensive care unit (PICU).Results: By univariate analysis, more HFOV patients had skin breakdown than did the CV patients (53% vs 12.5%, p = .001); HFOV patients also had greater severity of illness (Pediatric Risk of Mortality scores), higher mortality, and longer durations of neuromuscular blockade, low systolic blood pressure, and time exposed to risk. Life table analysis demonstrated no difference in the rate of skin breakdown between HFOV and CV patients. Multifactorial analysis showed that only PICU time at risk was a risk factor for skin breakdown.Conclusions: HFOV was not an independent risk factor for the development of skin breakdown. PICU time at risk was the sole risk factor for the development of skin breakdown in all mechanically ventilated patients in the PICU.     

Inhaled nitric oxide for a severe respiratory syncytial virus infection in an infant with bronchopulmonary dysplasia

Objective To report the first case of ARDS in children treated with nitric oxide (NO) inhalation.Methods A 13-months infant presented with BPD and severe hypoxemia related to RSV infection and ARDS. Inhaled NO was delivered in the ventilatory circuit of a continuous flow ventilator (Babylog 8000, Dräger) in a concentration of 20–80 ppm for 7 days. NO and NO₂ were continuously monitored (Polyton Draeger). Respiratory mechanics were evaluated by using the method of passive inflation by the ventilator.Results NO inhalation improved oxygenation (tcSaO₂) and reduced respiratory system resistance without affecting arterial pressure. NO₂ level remained below 5 ppm, and methaemoglobin level below 1%. The child survived without neurologic sequela.Conclusions Two mechanisms to explain oxygenation improvement can be suggested:selective improvement in perfusion of ventilated regions and bronchodilation.     

The neuroendocrine stress response and severity of acute respiratory syncytial virus bronchiolitis in infancy

Objective Neuroendocrine hormones have profound effects on the immune system. The immune response is a major factor in the pathogenesis of acute respiratory syncytial virus (RSV) infection. We hypothesised that there is a relationship between the neuroendocrine response in acute RSV infection, the severity of illness, and the degree of lymphopenia.Design Prospective, non-randomised cohort study of infants hospitalised for RSV infection requiring mechanical ventilation or managed conservatively. The study assessed the effect of age, gender, birth gestation, and severity of illness on stress hormone profile and its relationship to lymphocyte count.Setting Regional Paediatric Intensive Care Unit (PICU) and childrens wards.Patients Thirty-two consecutive infants with RSV infection were enrolled, of which thirteen were mechanically ventilated on PICU (study subjects) and nineteen treated on the ward (comparison group). Twenty-three children (72%) returned for follow-up.Measurements and main results A specific neuroendocrine profile was found in PICU patients compared to ward patients (Wilks Lambda = 0.36, F = 9.05, P =.03). PICU patients had significantly higher prolactin and growth hormone, and significantly lower leptin and IGF-1. Cortisol levels were the same. PICU patients were more lymphopenic compared to ward patients (P =.0001). On multiple regression analysis, prolactin and leptin levels accounted for 57% of the variation in lymphocyte count.Conclusions Whereas the effect of intensive care (mechanical ventilation and medication) could not be controlled for, our results suggest that there is an association between the neuroendocrine hormone response, severity of illness and degree of lymphopenia.Support: H.C. Roscoe Fellowship, British Medical Association, and Addenbrookes Paediatric Intensive Care Research Fund     

Effect of tidal volume in children with acute hypoxemic respiratory failure

Objectives  To determine if tidal volume (V _T) between 6 and 10 ml/kg body weight using pressure control ventilation affects outcome for children with acute hypoxemic respiratory failure (AHRF) or acute lung injury (ALI). To validate lung injury severity markers such as oxygenation index (OI), PaO₂/FiO₂ (PF) ratio, and lung injury score (LIS). Design  Retrospective, January 2000–July 2007. Setting  Tertiary care, 20-bed PICU. Patients  Three hundred and ninety-eight endotracheally intubated and mechanically ventilated children with PF ratio <300. Outcomes were mortality and 28-day ventilator free days. Measurements and main results  Three hundred and ninety-eight children met study criteria, with 20% mortality. 192 children had ALI. Using >90% pressure control ventilation, 85% of patients achieved V _T less than 10 ml/kg. Median V _T was not significantly different between survivors and non-survivors during the first 3 days of mechanical ventilation. After controlling for diagnostic category, age, delta P (PIP-PEEP), PEEP, and severity of lung disease, V _T was not associated with mortality (P > 0.1), but higher V _T at baseline and on day 1 of mechanical ventilation was associated with more ventilator free days (P < 0.05). This was particularly seen in patients with better respiratory system compliance [Crs > 0.5 ml/cmH₂0/kg, OR = 0.70 (0.52, 0.95)]. OI, PF ratio, and LIS were all associated with mortality (P < 0.05). Conclusions  When ventilating children using lung protective strategies with pressure control ventilation, observed V _T is between 6 and 10 ml/kg and is not associated with increased mortality. Moreover, higher V _T within this range is associated with more ventilator free days, particularly for patients with less severe disease. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Prognostic value of extravascular lung water index in critically ill children with acute respiratory failure

Purpose

In critically ill adults, a reduction in the extravascular lung water index (EVLWi) decreases time on mechanical ventilation and improves survival. The purpose of this study is to assess the prognostic value of EVLWi in critically ill children with acute respiratory failure and investigate its relationships with PaO₂, PaO₂/FiO₂ ratio, A-aDO₂, oxygenation index (OI), mean airway pressure, cardiac index, pulmonary permeability, and percent fluid overload.

Methods

Twenty-seven children admitted to PICU with acute respiratory failure received volumetric hemodynamic and blood gas monitoring following initial stabilization and every 4?h thereafter, until discharge from PICU or death. All patients are grouped in two categories: nonsurvivors and survivors.

Results

Children with a fatal outcome had higher values of EVLWi on admission to PICU, as well as higher A-aDO₂ and OI, and lower PaO₂ and PaO₂/FIO₂ ratio. After 24?h EVLWi decreased significantly only in survivors. As a survival indicator, EVLWi has good sensitivity and good specificity. Changes in EVLWi, OI, and mean airway pressure had a time-dependent influence on survival that proved significant according to the Cox test. Survivors spent fewer hours on mechanical ventilation. We detected a correlation of EVLWi with percent fluid overload and pulmonary permeability.

Conclusions

Like OI and mean airway pressure, EVLWi on admission to PICU is predictive of survival and of time needed on mechanical ventilation.     

High-frequency oscillatory ventilation in adult acute respiratory distress syndrome

Objective This study examined whether ARDS patients in whom predefined ventilator settings fail to maintain oxygenation and CO₂ removal can be safely transitioned to high-frequency oscillatory ventilation (HFOV), and whether HFOV use is efficacious.Design and setting Prospective observational study in the 14-bed intensive care unit of a university hospital.Patients and participants 42 patients with ARDS (APACHE II score 28 (IQR 24–37) and ventilation time prior HFOV 3.0 days (0.7–9.1).Measurements and results Gas exchange parameters and ventilator data were recorded before and during HFOV treatment (–12 h, –6 h, baseline, 10 min, 1 h, 6 h, 12 h, 24 h). Primary endpoints included: (a) P_aO₂/FIO₂ ratio 24 h after start of HFOV treatment or the last point of measurement if HFOV ended within the first 24 h; (b) HFOV-related complications. Post hoc analysis assessed the relationship between outcome and the response to HFOV, and between outcome and time of mechanical ventilation prior to HFOV. At baseline the median P_aO₂/FIO₂ ratio was 95 (IQR 62–129); after 24 h of HFOV the P_aO₂/FIO₂ ratio had increased significantly to 165 (88–225); only one patient developed a unilateral pneumothorax. Of the 42 patients 18 (43%) had died by day 30. Subset analyses showed a significantly higher 30-day mortality rate in patients with at least 3 days of mechanical ventilation prior to HFOV (64%) and in patients without oxygenation improvement after 24 h on HFOV (71%).Conclusions HFOV is an effective and safe method to ventilate ARDS patients. Failure to improve oxygenation within 24 h of HFOV is associated with high mortality.An editorial regarding this article can be found in the same issue     

Predicting patients' responses to changes in mechanical ventilation: a comparison between physicians and a physiological simulator

We compared the accuracy and reliability of a validated, physiological simulator and six intensive care specialists in predicting changes in arterial oxygen tension (PaO₂), arterial carbon dioxide tension (PaCO₂) and pH following adjustment of mechanical ventilation. Twenty-five data sets were collected before and after routine alterations in ventilator settings. Fractional inspired oxygen was adjusted in all patients and minute volume was adjusted in 13 patients. The simulator was more accurate and consistent than all the physicians in predicting the magnitude of PaO₂ and pH change. The simulator had a larger bias in estimating the magnitude of change of PaCO₂ than four of the physicians, but was more consistent than all but one of the physicians. The simulator may prove to be a useful tool in the management of mechanical ventilation. Incorporation into mechanical ventilators in a passive predictive role or an active ’closed-loop' ventilation management system are potential roles for physiological simulation. Received: 29 September 1998 Final revision received: 23 February 1999 Accepted: 23 April 1999     

Treatment of acute respiratory failure by helmet-delivered non-invasive pressure support ventilation in children with acute leukemia: a pilot study

Objective To evaluate the feasibility of non-invasive ventilation (NIV) through a new interface—the helmet—in the treatment of acute respiratory failure (ARF) in hematologic children.Design and setting Observational, non-randomized report of four consecutive cases. Pediatric Intensive Care Unit in a university hospital.Patients and methods Four consecutive females (aged 9–17 years) affected by acute leukemia (3 acute lymphocytic leukemia [ALL], 1 acute myeloid leukemia [AML]) and with hypoxemic ARF (defined by severe dyspnea at rest, respiratory rate >30 breaths/min, PaO₂:FiO₂ <200 and active contraction of the accessory muscles). Pressure support ventilation was delivered via a helmet (CaStar,Starmed, Italy) by means of an ICU ventilator (Servo 300, Siemens Elema, Sweden).Results We evaluated the effect of pressure support ventilation delivered by helmet on blood gases, respiratory rate, hemodynamics, patient tolerance, complication rate and outcome. An improvement of oxygenation was uniformly observed within the first 3 h after admission. The helmet was well tolerated by all children. No complication was observed. Two patients were discharged from the PICU in stable clinical conditions, whereas the remaining two children overcame the respiratory distress but had non-respiratory complications and eventually died.Conclusion Non-invasive ventilation via the helmet can offer effective ventilatory support and improve gas exchange in the treatment of ARF in pediatric hematologic patients. As already shown in adults, NIV may decrease the risk of life-threatening complications associated with invasive mechanical ventilation (MV), also in children with hematologic malignancies; moreover, it offers the possibility of an earlier approach to respiratory failure in this patient subset.     

俯卧位通气法在PICU呼吸窘迫综合征中的应用效果

目的 探讨俯卧位通气法对儿科重症监护室(pediatric intensive care unit,PICU)呼吸窘迫综合征(respiratory distress syndrom,RDS)患儿的影响.方法 选取2018年6月-2019年9月入住PICU呼吸窘迫综合征患儿作为研究对象,采用随机数字表法将其分为观察组3...     

High-frequency percussive ventilation attenuates lung injury in a rabbit model of gastric juice aspiration

Objective To test the effects of high-frequency percussive ventilation (HFPV) compared with high-frequency oscillatory ventilation (HFOV) and low-volume conventional mechanical ventilation (LVCMV), on lung injury course in a gastric juice aspiration model. Design Prospective, randomized, controlled, in-vivo animal study. Setting University animal research laboratory. Subjects Forty-three New Zealand rabbits. Interventions Lung injury was induced by intratracheal instillation of human gastric juice in order to achieve profound hypoxaemia (PaO₂/F_IO₂ ≤ 50). Animals were ventilated for 4 h after randomization in one of the following four groups: HFPV (median pressure 15 cmH₂O); LVCMV (V_T 6 ml kg^–1 and PEEP set to reach 15 cmH₂O plateau pressure); HFOV (mean pressure 15 cmH₂O); and a high-volume control group HVCMV (V_T 12 ml kg^–1 and ZEEP). Measurements and results Static respiratory compliance increased after the ventilation period in the HFPV, LVMCV and HFOV groups, in contrast with the HVCMV group. PaO₂/F_IO₂ improved similarly in the HFPV, LVCMV and HFOV groups, and remained lower in the HVCMV group than in the three others. Lung oedema, myeloperoxidase and histological lung injury score were higher in the HVCMV group, but not different among all others. Arterial lactate markedly increased after 4 h of ventilation in the HVCMV group, while lower but similar levels were observed in the three other groups. Conclusion HFPV, like HFOV and protective CMV, improves respiratory mechanics and oxygenation, and attenuates lung damage. The HFPV provides attractive lung protection, but further studies should confirm these results before introducing HFPV into the clinical arena.     

新生儿CPAP辅助通气的护理对策及对治疗效果和并发症的影响研究

目的 研究优质护理措施对新生儿CPAP辅助通气治疗效果和并发症的影响。方法 我院自2018年6月开始对新生儿CPAP的护理措施进行调整, 取调整前的患儿为对照组,调整后的患儿为研究组,比较两组患儿的PaCO₂、PaO₂和SpO₂指标,血压和心率指标, 机械通气时间、住院时间以及胸片改善的时间；并发症的发生率。结果 两组患儿通气前的PaCO₂、PaO₂和SpO₂指标,血压和心率指标差异无统计学意义(P>0.05)；通气后,PaCO₂研究组的值低于对照组,而PaO₂和SpO₂指标则高于对照组,两组患儿的血压均高于通气前,心率低于通气前,而研究组的血压高于对照组,心率低于对照组,研究组的住院时间、胸片改善时间和机械通气时间均短于对照组,两组患儿主要的并发症有呼吸机相关肺炎、气胸和肺不张,且研究组并发症的发生率低于对照组,且均有P<0.05,差异具有统计学意义。结论 对持续气道正压通气患儿实施优质的护理方式有利于降低持续气道正压通气并发症的发生率,提高对患儿的治疗效果。     

Acquisition of imipenem-resistant Acinetobacter baumannii in a pediatric intensive care unit: a case-control study

Objective To investigate the risk factors associated with nosocomial acquisition of imipenem-resistant Acinetobacter baumannii (IRAB) among pediatric intensive care patients.Abstract Design and setting A retrospective case control study was conducted in a pediatric intensive care unit (PICU).Patients and participants Cases were children in whom IRAB was isolated from any clinical specimen obtained at least 48 h following admission to PICU. Controls were children without IRAB matched to cases in 2:1 ratio. Twenty-six cases were matched with 52 controls according to the chronological order of admission.Measurements and results Between July 2001 and December 2003, 52 (62%) of 84 clinical A. baumannii isolates were found nonsusceptible to imipenem (MIC ≥ 8 μg/ml). Demographic variables, comorbid conditions, clinical picture at admission, invasive procedures, use of antimicrobials and other drugs were analyzed as potential risk factors. Use of carbapenems and other β-lactams, aminoglycosides, ranitidine, mechanical ventilation, central venous or urinary catheters and length of stay in PICU were among the factors significantly associated with IRAB acquisition in the univariate analysis. By multivariate analysis, however, only aminoglycoside use and length of stay in the PICU were independent risk factors.Conclusions Acquisition of IRAB by PICU patients was independently associated with aminoglycoside use and prolonged stay in the unit. Studies of evaluation of infection control policies need to be pursued.     

Inability to predict outcome of acute respiratory distress syndrome in children when using high frequency oscillation

Objective To (a) describe the experience with high-frequency oscillation (HFO) in children with acute respiratory distress syndrome (ARDS) unresponsive to conventional ventilation; (b) compare observed survival to that predicted by pediatric mortality scores and (c) determine if oxygenation index changes during HFO can predict survival.Design Retrospective, observational study.Setting A university hospital pediatric intensive care unit.Patients Nineteen children with ARDS (PaO₂/FIO₂<200) unresponsive to conventional ventilation treated with HFO from January 1995 to September 1996.Interventions None.Measurements and results The following were recorded: demographic, arterial blood gas and ventilator variables at the time points 0, 6, 12 and 24 h after the start of HFO; PRISM in the first 24 h of admission and pediatric respiratory failure and multiple organ system failure scores on the day of starting HFO. The mortality rate was 26% (5/19). The survival was better than predicted by the Pediatric Respiratory Failure score (p<0.01). None of the scores differentiated survivors from non-survivors (p>0.25). There was no significant change in oxygenation index over the first 24 h (p>0.18). Of patients with an initial oxygenation index higher than 20 who did not have at least a 20% reduction in oxygenation index by the time 6 h, 6/9 (67%) survived (sensitivity 75%, specificity 57%).Conclusions Survival in pediatric ARDS patients treated with HFO could not be predicted using several outcome scores or the oxygenation index (in the first 24 h). Survival was significantly better than predicted by the Pediatric Respiratory Failure score. A prospective randomized controlled trial of HFO in ARDS is warranted.     

Predictors of respiratory failure among previously healthy children with respiratory syncytial virus infection

Background

Respiratory syncytial virus (RSV)-related disease is the leading cause of hospitalization among infants, with approximately 7% to 21% of these patients developing acute respiratory failure.

Objective

The aim of this study was to identify clinical variables at initial presentation in the emergency department (ED) that may predict the subsequent need for mechanical ventilation among previously healthy, RSV-infected children who require pediatric intensive care unit (PICU) hospitalization.

Study design

This is a retrospective study of 67 previously healthy, RSV-infected patients admitted from January 1997 to March 2000 to the PICU. The primary outcome for this study was the need for mechanical ventilation. The relationship between clinical variables at initial ED presentation and the need for mechanical ventilation were explored using univariate and multiple logistic regression analysis.

Results

On multivariate analysis, the presence of lethargy (odds ratio [OR], 12.2; P = .005), grunting (OR, 9.3; P = .01), and a Paco₂ 65 mm Hg or greater (OR, 11.8; P = .013) were clinical factors at initial presentation in the ED associated with the subsequent need for mechanical ventilation among the study cohort. A developmental model that included lethargy, grunting, and a Paco₂ of 65 mm Hg or greater performed well as a prediction model. The developmental model had a sensitivity of 71%, specificity of 96%, a positive predictive value of 86%, and a negative predictive value of 91%.

Conclusions

The presence of lethargy, grunting, and a Paco₂ of 65 mm Hg or greater at initial presentation in the ED were predictive for the subsequent need for mechanical ventilation in previously healthy, RSV-infected children admitted to the PICU.     

Incidence and risk factors of gastrointestinal bleeding in mechanically ventilated patients

BACKGROUND:

The widespread use of gastrointestinal bleeding prophylaxis in critically ill patients was one of the most controversial issues. Since few studies reported the incidence of gastrointestinal bleeding in mechanically ventilated patients, this study aimed to identify the incidence and risk factors related to gastrointestinal bleeding in patients undergoing mechanical ventilation for more than 48 hours.

METHODS:

A total of 283 ICU patients who had received mechanical ventilation for longer than 48 hours at a provincial hospital affiliated to Shandong University from January 1, 2007 to December 31, 2009 were analyzed retrospectively. Those were excluded from the study if they had a history of gastrointestinal bleeding or ulceration, recent gastrointestinal surgery, brain death and active bleeding from the nose or throat. Demographic data of the patients included patient age, diagnosis on admission, duration of ICU stay, duration of ventilation, patterns and parameters of ventilation, ICU mortality, APACHE II score, multiple organ dysfunction, and indexes of biochemistry, kidney function, liver function and coagulation function. Risk factors of gastrointestinal bleeding were analyzed by univariate analysis and multiple logistic regression analysis.

RESULTS:

In the 242 patients who were given mechanical ventilation longer than 48 hours, the incidence of gastrointestinal bleeding was 46.7%. The bleeding in 3.3% of the patients was clinically significant. Significant risk factors were peak inspiratory pressure ≥30cmH₂O, renal failure, liver failure, PLT count<50×10⁹/L and prolonged APTT. Enteral nutrition had a beneficial effect on gastrointestinal bleeding. However, the multiple logistic regression analysis revealed that the independent risk factors of gastrointestinal bleeding were as follows: high pressure ventilator setting ≥ 30cmH₂O(RR=3.478, 95%CI=2.208-10.733), renal failure(RR=1.687, 95%CI = 1.098-3.482), PLT count<50×1 0⁹/L (RR=3.762, 95%CI=2.346-14.685), and prolonged APTT(RR=5.368, 95%CI=2.487-11.266). Enteral nutrition(RR=0.436, 95%CI= 0.346-0.764) was the independent protective factor.

CONCLUSIONS:

The incidence of gastrointestinal bleeding was high in the patients who received mechanical ventilation, and bleeding usually occurred within the first 48 hours. High pressure ventilator setting, renal failure, decreased PLT count and prolonged APTT were the significant risk factors of gastrointestinal bleeding. However, enteral nutrition was the independent protective factor.KEY WORDS: Mechanical ventilation, Gastrointestinal bleeding, Risk factors     

The effect of neuromuscular blockade on oxygen consumption in sedated and mechanically ventilated pediatric patients after cardiac surgery

Objective  To measure the effect of intense neuromuscular blockade (NMB) on oxygen consumption (VO₂) in deeply sedated and mechanically ventilated children on the first day after complex congenital cardiac surgery. Design  Prospective clinical interventional study. Setting  Pediatric intensive care unit of an university medical centre. Measurements and results  Nine mechanically ventilated and sedated children (weight 2.8–8.7 kg) were included. All children were treated with vasoactive drugs. The level of sedation was quantified using the comfort score, Ramsay score and bispectral index (BIS). The intensity of NMB was quantified using acceleromyography and VO₂ was measured using indirect calorimetry. Analgo-sedation using various intravenous agents was targeted at a deep level (comfort score < 18, BIS < 60 and Ramsay score > 4). NMB was achieved by intravenous administration of rocuronium. All measurements were conducted before, during and after recovery from a period of intense NMB. Baseline values were VO₂ 6.1 ml/(kg min) (SD 1.3), comfort score 13 (SD 0.7), BIS 42.5 (SD 14.2), mean blood pressure 54.0 mmHg (SD 10.5), mean heart rate 129.9 bpm (SD 28.9) and mean core temperature 36.7°C (SD 0.5). There were no significant differences in VO₂ or other parameters between baseline, during NMB and the recovery phase. Conclusion  Neuromuscular blocking agents do not reduce oxygen consumption in deeply sedated and mechanically ventilated children after congenital cardiac surgery.     

Non-invasive ventilation in chronic obstructive pulmonary disease patients: helmet versus facial mask

Rationale The helmet is a new interface with the potential of increasing the success rate of non-invasive ventilation by improving tolerance. Objectives To perform a physiological comparison between the helmet and the conventional facial mask in delivering non-invasive ventilation in hypercapnic patients with chronic obstructive pulmonary disease. Methods Prospective, controlled, randomized study with cross-over design. In 10 patients we evaluated gas exchange, inspiratory effort, patient–ventilator synchrony and patient tolerance after 30 min of non-invasive ventilation delivered either by helmet or facial mask; both trials were preceded by periods of spontaneous unassisted breathing. Measurements Arterial blood gases, inspiratory effort, duration of diaphragm contraction and ventilator assistance, effort-to-support delays (at the beginning and at the end of inspiration), number of ineffective efforts, and patient comfort. Main results Non-invasive ventilation improved gas exchange (p< 0.05) and inspiratory effort (p< 0.01) with both interfaces. The helmet, however, was less efficient than the mask in reducing inspiratory effort (p< 0.05) and worsened the patient–ventilator synchrony, as indicated by the longer delays to trigger on (p< 0.05) and cycle off (p< 0.05) the mechanical assistance and by the number of ineffective efforts (p< 0.005). Patient comfort was no different with the two interfaces. Conclusions Helmet and facial mask were equally tolerated and both were effective in ameliorating gas exchange and decreasing inspiratory effort. The helmet, however, was less efficient in decreasing inspiratory effort and worsened the patient–ventilator interaction. Electronic supplementary material Supplementary material is available in the online version of this article at and is accessible for authorized users. Financial support: None     

Respiratory syncytial virus morbidity, premorbid factors, seasonality, and implications for prophylaxis

Objectives

We investigated factors associated with morbidity and pediatric intensive care unit (PICU) admission in children with respiratory syncytial virus (RSV) infection and explored seasonality and implication of prophylaxis.

Methods

A retrospective study between 2006 and 2008 of every child with a laboratory-confirmed RSV infection was included.

Results

Six hundred seventy RSV admissions were identified. Ten (1.5%) required PICU admissions. Children admitted to PICU were younger than non-PICU admissions (median [interquartile range] age, 0.3 [0.11-0.48] vs 1.18 [0.46-2.49] years; P = .001). Odds associated with PICU admissions included history of chronic lung disease (odds ratio [95% confidence interval], 18.08 [2.29-114.95]; P = .010), history of acyanotic heart disease (7.61 [1.04-42.59], P = .043), and neurodevelopmental conditions (mental retardation, cerebral palsy, or neuromuscular disease; 8.41 [1.63-38.57], P = .012). Odds of bacterial coinfections was 13.50 (1.77-81.29), P = .017. There appeared no significant PICU predilection in terms of sex, history of prematurity, cyanotic heart disease, seizure disorders, chromosomal disorders, or malignancy. Admissions associated with proven RSV infections accounted for 2.4% of PICU annual admissions. The duration of PICU stay was generally brief (median, 3 days). However, median length of hospital stay was significantly longer in the PICU category (8.5 vs 3 days, P < .001). There was no death in the study period. Only 5 (0.75%) of 665 patients were readmitted to the pediatric infectious disease isolation ward in consecutive years, and none required PICU support. Twenty (3%) of admissions involved neonates younger than 30 days. There was no definite seasonality, but incidence was lowest between October and January.

Conclusions

Most infants have mild disease and do not require PICU support. Young infants with history of chronic lung disease, congenital heart disease, and neurodevelopmental conditions appear to be at significantly increased risk for PICU support. There is no winter seasonality for RSV disease in Hong Kong. Therefore, any prophylaxis for at-risk population should provide adequate coverage for the warmer months in subtropical regions.