4A randomized trial of prolonged prone positioning in children with acute respiratory failure

Characterization of Global Research Trends and Prospects on Prone Positioning in Respiratory Failure: Bibliometric Analysis

Background

Prone positioning has emerged as a crucial intervention in managing acute respiratory failure, especially in acute respiratory distress syndrome and patients with COVID-19. Given the increasing interest in this field, it is important to characterize global research trends and key contributors to identify future research directions.

Objective

This study aimed to analyze global research trends, collaboration networks, and research hotspots related to prone positioning in respiratory failure through a comprehensive bibliometric analysis.

Methods

Bibliometric analyses were conducted using CiteSpace and Biblioshiny software on publications up to December 31, 2023, from the Web of Science Core Collection, focusing on prone positioning in respiratory failure.

Results

A total of 1263 research articles were identified, published in 50 countries by numerous institutions. The United States, France, and Germany contributed the most publications, with the United States producing 21.9% (275/1263) of the total. Key authors such as Claude Guerin and Luciano Gattinoni were identified as major contributors to the field. Keyword co-occurrence analysis revealed the dynamic nature of prone positioning research in respiratory failure. It highlighted protective ventilation and COVID-19-related acute respiratory distress syndrome as emerging hotspots, indicating a shift in focus during the pandemic.

Conclusions

This study revealed a rapidly growing body of literature on prone positioning in respiratory failure, especially in the context of COVID-19. The findings underscore the importance of further multicenter clinical trials to validate current practices and refine treatment protocols. In addition, the application of prone positioning in non-intubated patients represents a potential future research direction.

Pulmonary Specific Ancillary Treatment for Pediatric Acute Respiratory Distress Syndrome: From the Second Pediatric Acute Lung Injury Consensus Conference

OBJECTIVES

We conducted an updated review of the literature on pulmonary-specific ancillary therapies for pediatric acute respiratory distress syndrome (PARDS) to provide an update to the Pediatric Acute Lung Injury Consensus Conference recommendations and statements about clinical practice and research.

DATA SOURCES

MEDLINE (Ovid), Embase (Elsevier), and CINAHL Complete (EBSCOhost).

STUDY SELECTION

Searches were limited to children, PARDS or hypoxic respiratory failure and overlap with pulmonary-specific ancillary therapies.

DATA EXTRACTION

Title/abstract review, full-text review, and data extraction using a standardized data collection form.

DATA SYNTHESIS

The Grading of Recommendations Assessment, Development, and Evaluation approach was used to identify and summarize evidence and develop recommendations. Twenty-six studies were identified for full-text extraction. Four clinical recommendations were generated, related to use of inhaled nitric oxide, surfactant, prone positioning, and corticosteroids. Two good practice statements were generated on the use of routine endotracheal suctioning and installation of isotonic saline prior to endotracheal suctioning. Three research statements were generated related to: the use of open versus closed suctioning, specific methods of airway clearance, and various other ancillary therapies.

CONCLUSIONS

The evidence to support or refute any of the specific ancillary therapies in children with PARDS remains low. Further investigation, including a focus on specific subpopulations, is needed to better understand the role, if any, of these various ancillary therapies in PARDS.

Positioning for acute respiratory distress in hospitalised infants and children

BACKGROUND

Acute respiratory distress syndrome (ARDS) is a significant cause of hospitalisation and death in young children. Positioning and mechanical ventilation have been regularly used to reduce respiratory distress and improve oxygenation in hospitalised patients. Due to the association of prone positioning (lying on the abdomen) with sudden infant death syndrome (SIDS) within the first six months, it is recommended that young infants be placed on their back (supine). However, prone positioning may be a non-invasive way of increasing oxygenation in individuals with acute respiratory distress, and offers a more significant survival advantage in those who are mechanically ventilated. There are substantial differences in respiratory mechanics between adults and infants. While the respiratory tract undergoes significant development within the first two years of life, differences in airway physiology between adults and children become less prominent by six to eight years old. However, there is a reduced risk of SIDS during artificial ventilation in hospitalised infants. Thus, an updated review focusing on positioning for infants and young children with ARDS is warranted. This is an update of a review published in 2005, 2009, and 2012.

OBJECTIVES

To compare the effects of different body positions in hospitalised infants and children with acute respiratory distress syndrome aged between four weeks and 16 years.

SEARCH METHODS

We searched CENTRAL, which contains the Acute Respiratory Infections Group's Specialised Register, MEDLINE, Embase, and CINAHL from January 2004 to July 2021.

SELECTION CRITERIA

Randomised controlled trials (RCTs) or quasi-RCTs comparing two or more positions for the management of infants and children hospitalised with ARDS.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data from each study. We resolved differences by consensus, or referred to a third contributor to arbitrate. We analysed bivariate outcomes using an odds ratio (OR) and 95% confidence interval (CI). We analysed continuous outcomes using a mean difference (MD) and 95% CI. We used a fixed-effect model, unless heterogeneity was significant (I² statistic > 50%), when we used a random-effects model.

MAIN RESULTS

We included six trials: four cross-over trials, and two parallel randomised trials, with 198 participants aged between 4 weeks and 16 years, all but 15 of whom were mechanically ventilated. Four trials compared prone to supine positions. One trial compared the prone position to good-lung dependent (where the person lies on the side of the healthy lung, e.g. if the right lung was healthy, they were made to lie on the right side), and independent (or non-good-lung independent, where the person lies on the opposite side to the healthy lung, e.g. if the right lung was healthy, they were made to lie on the left side) position. One trial compared good-lung independent to good-lung dependent positions. When the prone (with ventilators) and supine positions were compared, there was no information on episodes of apnoea or mortality due to respiratory events. There was no conclusive result in oxygen saturation (SaO_2; MD 0.40 mmHg, 95% CI -1.22 to 2.66; 1 trial, 30 participants; very low certainty evidence); blood gases, PCO₂ (MD 3.0 mmHg, 95% CI -1.93 to 7.93; 1 trial, 99 participants; low certainty evidence), or PO₂ (MD 2 mmHg, 95% CI -5.29 to 9.29; 1 trial, 99 participants; low certainty evidence); or lung function (PaO₂/FiO₂ ratio; MD 28.16 mmHg, 95% CI -9.92 to 66.24; 2 trials, 121 participants; very low certainty evidence). However, there was an improvement in oxygenation index (FiO₂% X M_PAW/ PaO₂) with prone positioning in both the parallel trials (MD -2.42, 95% CI -3.60 to -1.25; 2 trials, 121 participants; very low certainty evidence), and the cross-over study (MD -8.13, 95% CI -15.01 to -1.25; 1 study, 20 participants). Derived indices of respiratory mechanics, such as tidal volume, respiratory rate, and positive end-expiratory pressure (PEEP) were reported. There was an apparent decrease in tidal volume between prone and supine groups in a parallel study (MD -0.60, 95% CI -1.05 to -0.15; 1 study, 84 participants; very low certainty evidence). When prone and supine positions were compared in a cross-over study, there were no conclusive results in respiratory compliance (MD 0.07, 95% CI -0.10 to 0.24; 1 study, 10 participants); changes in PEEP (MD -0.70 cm H₂O, 95% CI -2.72 to 1.32; 1 study, 10 participants); or resistance (MD -0.00, 95% CI -0.05 to 0.04; 1 study, 10 participants). One study reported adverse events. There were no conclusive results for potential harm between groups in extubation (OR 0.57, 95% CI 0.13 to 2.54; 1 trial, 102 participants; very low certainty evidence); obstructions of the endotracheal tube (OR 5.20, 95% CI 0.24 to 111.09; 1 trial, 102 participants; very low certainty evidence); pressure ulcers (OR 1.00, 95% CI 0.41 to 2.44; 1 trial, 102 participants; very low certainty evidence); and hypercapnia (high levels of arterial carbon dioxide; OR 3.06, 95% CI 0.12 to 76.88; 1 trial, 102 participants; very low certainty evidence). One study (50 participants) compared supine positions to good-lung dependent and independent positions. There was no conclusive evidence that PaO₂ was different between supine and good-lung dependent positioning (MD 3.44 mm Hg, 95% CI -23.12 to 30.00; 1 trial, 25 participants; very low certainty evidence). There was also no conclusive evidence for supine position and good-lung independent positioning (MD -2.78 mmHg, 95% CI -28.84, 23.28; 25 participants; very low certainty evidence); or between good-lung dependent and independent positioning (MD 6.22, 95% CI -21.25 to 33.69; 1 trial, 25 participants; very low certainty evidence). As most trials did not describe how possible biases were addressed, the potential for bias in these findings is unclear.

AUTHORS' CONCLUSIONS

Although included studies suggest that prone positioning may offer some advantage, there was little evidence to make definitive recommendations. There appears to be low certainty evidence that positioning improves oxygenation in mechanically ventilated children with ARDS. Due to the increased risk of SIDS with prone positioning and lung injury with artificial ventilation, it is recommended that hospitalised infants and children should only be placed in this position while under continuous cardiorespiratory monitoring.

Surviving sepsis campaign international guidelines for the management of septic shock and sepsis-associated organ dysfunction in children

OBJECTIVES

To develop evidence-based recommendations for clinicians caring for children (including infants, school-aged children, and adolescents) with septic shock and other sepsis-associated organ dysfunction.

DESIGN

A panel of 49 international experts, representing 12 international organizations, as well as three methodologists and three public members was convened. Panel members assembled at key international meetings (for those panel members attending the conference), and a stand-alone meeting was held for all panel members in November 2018. A formal conflict-of-interest policy was developed at the onset of the process and enforced throughout. Teleconferences and electronic-based discussion among the chairs, co-chairs, methodologists, and group heads, as well as within subgroups, served as an integral part of the guideline development process.

METHODS

The panel consisted of six subgroups: recognition and management of infection, hemodynamics and resuscitation, ventilation, endocrine and metabolic therapies, adjunctive therapies, and research priorities. We conducted a systematic review for each Population, Intervention, Control, and Outcomes question to identify the best available evidence, statistically summarized the evidence, and then assessed the quality of evidence using the Grading of Recommendations Assessment, Development, and Evaluation approach. We used the evidence-to-decision framework to formulate recommendations as strong or weak, or as a best practice statement. In addition, "in our practice" statements were included when evidence was inconclusive to issue a recommendation, but the panel felt that some guidance based on practice patterns may be appropriate.

RESULTS

The panel provided 77 statements on the management and resuscitation of children with septic shock and other sepsis-associated organ dysfunction. Overall, six were strong recommendations, 49 were weak recommendations, and nine were best-practice statements. For 13 questions, no recommendations could be made; but, for 10 of these, "in our practice" statements were provided. In addition, 52 research priorities were identified.

CONCLUSIONS

A large cohort of international experts was able to achieve consensus regarding many recommendations for the best care of children with sepsis, acknowledging that most aspects of care had relatively low quality of evidence resulting in the frequent issuance of weak recommendations. Despite this challenge, these recommendations regarding the management of children with septic shock and other sepsis-associated organ dysfunction provide a foundation for consistent care to improve outcomes and inform future research.

Surviving Sepsis Campaign International Guidelines for the Management of Septic Shock and Sepsis-Associated Organ Dysfunction in Children

OBJECTIVES

To develop evidence-based recommendations for clinicians caring for children (including infants, school-aged children, and adolescents) with septic shock and other sepsis-associated organ dysfunction.

DESIGN

A panel of 49 international experts, representing 12 international organizations, as well as three methodologists and three public members was convened. Panel members assembled at key international meetings (for those panel members attending the conference), and a stand-alone meeting was held for all panel members in November 2018. A formal conflict-of-interest policy was developed at the onset of the process and enforced throughout. Teleconferences and electronic-based discussion among the chairs, co-chairs, methodologists, and group heads, as well as within subgroups, served as an integral part of the guideline development process.

METHODS

The panel consisted of six subgroups: recognition and management of infection, hemodynamics and resuscitation, ventilation, endocrine and metabolic therapies, adjunctive therapies, and research priorities. We conducted a systematic review for each Population, Intervention, Control, and Outcomes question to identify the best available evidence, statistically summarized the evidence, and then assessed the quality of evidence using the Grading of Recommendations Assessment, Development, and Evaluation approach. We used the evidence-to-decision framework to formulate recommendations as strong or weak, or as a best practice statement. In addition, "in our practice" statements were included when evidence was inconclusive to issue a recommendation, but the panel felt that some guidance based on practice patterns may be appropriate.

RESULTS

The panel provided 77 statements on the management and resuscitation of children with septic shock and other sepsis-associated organ dysfunction. Overall, six were strong recommendations, 52 were weak recommendations, and nine were best-practice statements. For 13 questions, no recommendations could be made; but, for 10 of these, "in our practice" statements were provided. In addition, 49 research priorities were identified.

CONCLUSIONS

A large cohort of international experts was able to achieve consensus regarding many recommendations for the best care of children with sepsis, acknowledging that most aspects of care had relatively low quality of evidence resulting in the frequent issuance of weak recommendations. Despite this challenge, these recommendations regarding the management of children with septic shock and other sepsis-associated organ dysfunction provide a foundation for consistent care to improve outcomes and inform future research.

Fluid balance in pediatric patients in prone position: a pragmatic study

OBJECTIVE

To verify the association between prone position, increased diuresis, and decreased cumulative fluid balance in critically ill pediatric patients who underwent mechanical ventilation (MV) for pulmonary causes and describe adverse events related to the use of the position.

METHODS

This is a retrospective observational study. Patients aged between 1 month and 12 years who underwent MV for pulmonary causes, between January 2013 and December 2015, were selected and divided between those who were put on prone position (PG) and those who were not (CG) during the hospitalization at the Pediatric Intensive Care Unit (PICU). Data were analyzed longitudinally from D1 to D4.

RESULTS

A total of 77 patients (PG = 37 and CG = 40) were analyzed. The general characteristics of both groups were similar. In the comparison between the groups, there was no increase in diuresis or decrease in cumulative fluid balance in the prone group. In the longitudinal analysis of D1 to D4, we saw that the PG presented higher diuresis (p = 0.034) and a lower cumulative fluid balance (p = 0.001) in D2. Regarding the use of diuretics, there was greater use of furosemide (P <0.001) and spironolactone (P = 0.04) in the PG. There was no increase in adverse events during the use of the prone position.

CONCLUSION

The prone position was not associated with increased diuresis or decreased cumulative fluid balance in critically ill pediatric patients who underwent to MV for pulmonary causes.

Prone Positioning Improves Ventilation Homogeneity in Children With Acute Respiratory Distress Syndrome

OBJECTIVES

To determine the effect of prone positioning on ventilation distribution in children with acute respiratory distress syndrome.

DESIGN

Prospective observational study.

SETTING

Paediatric Intensive Care at Red Cross War Memorial Children's Hospital, Cape Town, South Africa.

PATIENTS

Mechanically ventilated children with acute respiratory distress syndrome.

INTERVENTIONS

Electrical impedance tomography measures were taken in the supine position, after which the child was turned into the prone position, and subsequent electrical impedance tomography measurements were taken.

MEASUREMENTS AND MAIN RESULTS

Thoracic electrical impedance tomography measures were taken at baseline and after 5, 20, and 60 minutes in the prone position. The proportion of ventilation, regional filling characteristics, and global inhomogeneity index were calculated for the ventral and dorsal lung regions. Arterial blood gas measurements were taken before and after the intervention. A responder was defined as having an improvement of more than 10% in the oxygenation index after 60 minutes in prone position. Twelve children (nine male, 65%) were studied. Four children were responders, three were nonresponders, and five showed no change to prone positioning. Ventilation in ventral and dorsal lung regions was no different in the supine or prone positions between response groups. The proportion of ventilation in the dorsal lung increased from 49% to 57% in responders, while it became more equal between ventral and dorsal lung regions in the prone position in nonresponders. Responders showed greater improvements in ventilation homogeneity with R improving from 0.86 ± 0.24 to 0.98 ± 0.02 in the ventral lung and 0.91 ± 0.15 to 0.99 ± 0.01 in the dorsal lung region with time in the prone position.

CONCLUSIONS

The response to prone position was variable in children with acute respiratory distress syndrome. Prone positioning improves homogeneity of ventilation and may result in recruitment of the dorsal lung regions.

Pediatric Acute Hypoxemic Respiratory Failure: Management of Oxygenation

Acute hypoxemic respiratory failure (AHRF) is one of the hallmarks of acute lung injury (ALI) and acute respiratory distress syndrome (ARDS), which are caused by an inflammatory process initiated by any of a number of potential systemic and/or pulmonary insults that result in heterogeneous disruption of the capillary-pithelial interface. In these critically sick patients, optimizing the management of oxygenation is crucial. Physicians managing pediatric patients with ALI or ARDS are faced with a complex array of options influencing oxygenation. Certain treatment strategies can influence clinical outcomes, such as a lung protective ventilation strategy that specifies a low tidal volume (6 mL/kg) and a plateau pressure limit (30 cm H2O). Other strategies such as different levels of positive end expiratory pressure, altered inspiration to expiration time ratios, recruitment maneuvers, prone positioning, and extraneous gases or drugs may also affect clinical outcomes. This article reviews state-of-the-art strategies on the management of oxygenation in acute hypoxemic respiratory failure in children.

Chest Physiotherapy in the Pediatric Intensive Care Unit

Despite widespread practice, there is very little, high-level evidence supporting the indications for and effectiveness of cardiopulmonary/chest physiotherapy (CPT) in critically ill infants and children. Conversely, most studies highlight the detrimental effects or lack of effect of different manual modalities. Conventional CPT should not be a routine intervention in the pediatric intensive care unit, but can be considered when obstructive secretions are present which impact on lung mechanics and/or gaseous exchange and/or where there is the potential for long-term complications. Techniques such as positioning, early mobilization, and rehabilitation have been shown to be beneficial in adult intensive care patients; however, little attention has been paid to this important area of practice in pediatric intensive care units. This article presents a narrative review of chest physiotherapy in pediatric critical illness, including effects, indications, precautions, and specific treatment modalities and techniques.

Optimizing functional MR urography: prime time for a 30-minutes-or-less fMRU

BACKGROUND

Current protocols for functional MR urography (fMRU) require long scan times, limiting its widespread use.

OBJECTIVE

Our goal was to use pre-defined criteria to reduce the number of sequences and thus the examination time without compromising the morphological and functional results.

MATERIALS AND METHODS

The standard fMRU protocol in our department consists of eight sequences, including a 17-min dynamic post-contrast scan. Ninety-nine children and young adults (43 male, 56 female, mean age 7 years) were evaluated with this protocol. Each sequence was retrospectively analyzed for its utility and factors that affect its duration.

RESULTS

Mean scan time to perform the eight sequences, without including the variable time between sequences, was 40.5 min. Five sequences were categorized as essential: (1) sagittal T2 for planning the oblique coronal plane, (2) axial T2 with fat saturation for the assessment of corticomedullary differentiation and parenchymal thickness, (3) coronal 3-D T2 with fat saturation for multiplanar and 3-D reconstructions, (4) pre-contrast coronal T1 with fat saturation to ensure an appropriate scan prior to injecting the contrast material and (5) the coronal post-contrast dynamic series. Functional information was obtained after 8 min of dynamic imaging in the majority of children. The coronal fat-saturated T2, coronal T1, and post-contrast sagittal fat-saturated T1 sequences did not provide additional information. Because of the effects of pelvicalyceal dilation and ureteropelvic angle on the renal transit time, prone position is recommended, at least in children with high-grade pelvicalyceal dilation.

CONCLUSION

Comprehensive fMRU requires approximately 19 min for sequence acquisition. Allowing for time between sequences and motion correction, the total study time can be reduced to about 30 min. Four pre-contrast sequences and a shortened post-contrast dynamic scan, optimally with the child in prone position, are sufficient.

Pulmonary specific ancillary treatment for pediatric acute respiratory distress syndrome: proceedings from the Pediatric Acute Lung Injury Consensus Conference

OBJECTIVE

To provide an overview of the current literature on pulmonary-specific therapeutic approaches to pediatric acute respiratory distress syndrome to determine recommendations for clinical practice and/or future research.

DATA SOURCES

PubMed, EMBASE, CINAHL, SCOPUS, and the Cochrane Library were searched from inception until January 2013 using the following keywords in various combinations: ARDS, treatment, nitric oxide, heliox, steroids, surfactant, etanercept, prostaglandin therapy, inhaled beta adrenergic receptor agonists, N-acetylcysteine, ipratroprium bromide, dornase, plasminogen activators, fibrinolytics or other anticoagulants, and children. No language restrictions were applied. References from identified articles were searched for additional publications.

STUDY SELECTION

All clinical studies pertaining to pulmonary-specific therapeutic approaches to pediatric acute respiratory distress syndrome were reviewed. If clinical pediatric data were sparse or unavailable, the findings from studies of adult acute respiratory distress syndrome and animal models that might be relevant to pediatric acute respiratory distress syndrome were examined.

DATA EXTRACTION

All relevant studies were reviewed and pertinent data abstracted.

DATA SYNTHESIS

Over the course of three international meetings, the pertinent findings of the literature review were discussed by a panel of 24 experts in the field representing 21 academic institutions and 8 countries. Recommendations developed and the supporting literature were distributed to all panel members without a conflict of interest and were scored by using the Research ANd Development/University of California, Los Angeles Appropriateness method. The modified Delphi approach was used as the methodology to achieve consensus among the panel.

CONCLUSIONS

Overall, the routine use of surfactant, inhaled nitric oxide, glucocorticoids, prone positioning, endotracheal suctioning, and chest physiotherapy cannot be recommended. Inhaled nitric oxide should only be used for patients with documented pulmonary hypertension and/or right ventricular failure. Prone positioning may be considered in patients with severe pediatric acute respiratory distress syndrome. Future studies are definitely warranted to establish the role, if any, of these ancillary treatment modalities in pediatric acute respiratory distress syndrome.

Positioning for acute respiratory distress in hospitalised infants and children

BACKGROUND

Because of the association of prone positioning with sudden infant death syndrome (SIDS) it is recommended that young infants be placed on their backs (supine). However, the prone position may be a non-invasive way of increasing oxygenation in participants with acute respiratory distress. Because of substantial differences in respiratory mechanics between adults and children and the risk of SIDS in young infants, a specific review of positioning for infants and young children with acute respiratory distress is warranted.

OBJECTIVES

To compare the effects of different body positions in hospitalised infants and children with acute respiratory distress.

SEARCH METHODS

We searched Cochrane Central Register of Controlled Trials (CENTRAL 2012, Issue 3), which contains the Acute Respiratory Infections Group's Specialised Register, MEDLINE (1966 to April week 1, 2012), EMBASE (2004 to April 2012) and CINAHL (2004 to April 2012).

SELECTION CRITERIA

Randomised controlled trials (RCTs) or pseudo-RCTs comparing two or more positions in the management of infants and children hospitalised with acute respiratory distress.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted data from each study. We resolved differences by consensus or referral to a third review author. We analysed bivariate outcomes using an odds ratio and 95% confidence interval (CI). We analysed continuous outcomes using a mean difference and 95% CI. We used a fixed-effect model unless heterogeneity was significant, in which case we used a random-effects model.

MAIN RESULTS

We extracted data from 53 studies. We included 24 studies with a total of 581 participants. Three studies used a parallel-group, randomised design which compared prone and supine positions only. The remaining 21 studies used a randomised cross-over design. These studies compared prone, supine, lateral, elevated and flat positions.Prone positioning was significantly more beneficial than supine positioning in terms of oxygen saturation (mean difference (MD) 1.97%, 95% CI 1.18 to 2.77), arterial oxygen (MD 6.24 mm Hg, 95% confidence interval (CI) 2.20 to 10.28), episodes of hypoxaemia (MD -3.46, 95% CI -4.60 to -2.33) and thoracoabdominal synchrony (MD -30.76, 95% CI -41.39 to -20.14). No adverse effects were identified. There were no statistically significant differences between any other positions.As the majority of studies did not describe how possible biases were addressed, the potential for bias in these findings is unclear.

AUTHORS' CONCLUSIONS

The prone position was significantly superior to the supine position in terms of oxygenation. However, as most participants were ventilated preterm infants, the benefits of prone positioning may be most relevant to these infants. In addition, although placing infants and children in the prone position may improve respiratory function, the association of SIDS with prone positioning means that infants should only be placed in this position while under continuous cardiorespiratory monitoring.

Benefícios do decúbito ventral associado ao CPAP em recém-nascidos prematuros

O objetivo deste estudo foi avaliar os benefícios nas variáveis clínicas do decúbito ventral (DV) associado a pressão positiva contínua nas vias aéreas (CPAP), em recém-nascido pré-termo (RNPT). Foi feito um estudo transversal em RNPT com utilização do CPAP internados na unidade de terapia intensiva (UTI). As frequências cardíaca (FC) e respiratória (FR), SpO2, quantificação do desconforto respiratório pelo boletim de Silverman e Andersen (BSA: quanto maior o valor, pior o desconforto respiratório) foram avaliados em cinco fases. Na fase I foram avaliadas a FC, FR, SpO2 e BSA em decúbito supino. Nas fases II, III, IV e V foram coletadas as mesmas variáveis da fase I após 5, 15, 30 e 60 min, respectivamente. O RNPT foi posicionado em DV logo após a fase I. Foi realizada análise de variância repetida para comparação entre todas as variáveis estudadas nas cinco fases, e utilizado-se teste de Bonferroni para análise post hoc. Foi considerada significância estatística quando p<0,05. No estudo, foram incluídos 13 RNPT, com média idade gestacional 33±1,5 semanas, sendo 7 do gênero masculino. Não houve alteração significante na FC, FR e SpO2, entre todas as fases. Houve redução no BSA nas fases III e IV quando comparadas à fase I: fase 1, 4,6±1,6 vs. fase III, 2,4±0,5 (p=0,02); fase I, 4,6±1,6 vs. fase IV, 2,4±0,5 (p=0,002). Concluiu-se, então, então que DV reduz o desconforto respiratório em RNPT quando associado ao CPAP, quando permanecem por, pelo menos, 15 min, sem alteração na FC, FR e SpO2.

Extracorporeal membrane oxygenation for pediatric respiratory failure: Survival and predictors of mortality

OBJECTIVE

The last multicentered analysis of extracorporeal membrane oxygenation in pediatric acute respiratory failure was completed in 1993. We reviewed recent international data to evaluate survival and predictors of mortality.

DESIGN

Retrospective case series review.

SETTING

The Extracorporeal Life Support Organization Registry, which includes data voluntarily submitted from over 115 centers worldwide, was queried. The work was completed at the Division of Pediatric Critical Care, Department of Pediatrics, Primary Children's Medical Center, University of Utah, Salt Lake City, UT.

SUBJECTS

Patients aged 1 month to 18 yrs supported with extracorporeal membrane oxygenation for acute respiratory failure from 1993 to 2007.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

There were 3,213 children studied. Overall survival remained relatively unchanged over time at 57%. Considerable variability in survival was found based on pulmonary diagnosis, ranging from 83% for status asthmaticus to 39% for pertussis. Comorbidities significantly decreased survival to 33% for those with renal failure (n = 329), 16% with liver failure (n = 51), and 5% with hematopoietic stem cell transplantation (n = 22). The proportion of patients with comorbidities increased from 19% during 1993 to 47% in 2007. Clinical factors associated with mortality included precannulation ventilatory support longer than 2 wks and lower precannulation blood pH.

CONCLUSIONS

Although the survival of pediatric patients with acute respiratory failure treated with extracorporeal membrane oxygenation has not changed, this treatment is currently offered to increasingly medically complex patients. Mechanical ventilation in excess of 2 wks before the initiation of extracorporeal membrane oxygenation is associated with decreased survival.

Pediatric acute lung injury

Among ventilated children, the incidence of acute lung injury (ALI) was 9%; of that latter group 80% developed the acute respiratory distress syndrome (ARDS). The population-based prevalence of pediatric ARDS was 5.5 cases/100.000 inhabitants. Underlying diseases in children were septic shock (34%), respiratory syncytial virus infections (16%), bacterial pneumonia (15%), near-drowning 9%, and others. Mortality ranged from 18% to 27% for ALI (including ALI-non ARDS and ARDS) and from 29% to 50% for ARDS. Mortality was only 3%-11% in children with ALI-non ARDS. As risk factors, oxygenation indices and multi-organ failure have been identified. New insights into the pathophysiology (for example the interplay between intraalveolar coagulation/fibrinolysis and inflammation and the genetic polymorphism for the angiotensin-converting enzyme) offer new therapeutic options. Lung protective mechanical ventilation with optimal lung recruitment is the mainstay of supportive therapy. New therapeutic modalities refer to corticosteroid and surfactant treatment. Well-designed follow up studies are needed.

Prone equals prone? Impact of positioning techniques on respiratory function in anesthetized and paralyzed healthy children

OBJECTIVES

Although the prone position is effectively used to improve oxygenation, its impact on functional residual capacity is controversial. Different techniques of body positioning might be an important confounding factor. The aim of this study was to determine the impact of two different prone positioning techniques on functional residual capacity and ventilation distribution in anesthetized, preschool-aged children.

DESIGN

Functional residual capacity and lung clearance index, a measure of ventilation homogeneity, were calculated using a sulfur-hexafluoride multibreath washout technique. After intubation, measurements were taken in the supine position and, in random order, in the flat prone position and the augmented prone position (gel pads supporting the pelvis and the upper thorax).

SETTING

Pediatric anesthesia unit of university hospital.

PATIENTS AND PARTICIPANTS

Thirty preschool children without cardiopulmonary disease undergoing elective surgery.

MEASUREMENTS AND RESULTS

Mean (range) age was 48.5 (24-80) months, weight 17.2 (10.5-26.9) kg, functional residual capacity (mean +/- SD) 22.9+/- 6.2 ml.kg (-1) in the supine position and 23.3 +/- 5.6 ml.kg (-1) in the flat prone position, while lung clearance indices were 8.1 +/- 2.3 vs. 7.9 +/- 2.3, respectively. In contrast, functional residual capacity increased to 27.6 +/- 6.5 ml.kg (-1) (p< 0.001) in the augmented prone position while at the same time the lung clearance index decreased to 6.7 +/- 0.9 (p< 0.001).

CONCLUSIONS

Functional residual capacity and ventilation distribution were similar in the supine and flat prone positions, while these parameters improved significantly in the augmented prone position, suggesting that the technique of prone positioning has major implications for pulmonary function.

Have changes in ventilation practice improved outcome in children with acute lung injury?

OBJECTIVES

To describe the changes that have occurred in mechanical ventilation in children with acute lung injury in our institution over the last 10-15 yrs and to examine the impact of these changes, in particular of the delivered tidal volume on mortality.

DESIGN

Retrospective study.

SETTING

University-affiliated children's hospital.

PATIENTS

The management of mechanical ventilation between 1988 and 1992 (past group, n = 79) was compared with the management between 2000 and 2004 (recent group, n = 85).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The past group patients were ventilated with a significantly higher mean tidal volume (10.2 +/- 1.7 vs. 8.1 +/- 1.4 mL.kg actual body weight, p < .001), lower levels of positive end-expiratory pressure (6.1 +/- 2.7 vs. 7.1 +/- 2.4 cm H2O, p = .007), and higher mean peak inspiratory pressure (31.5 +/- 7.3 vs. 27.8 +/- 4.2 cm H2O, p < .001) than the recent group patients. The recent group had a lower mortality (21% vs. 35%, p = .04) and a greater number of ventilator-free days (16.0 +/- 9.0 vs. 12.6 +/- 9.9 days, p = .03) than the past group. A higher tidal volume was independently associated with increased mortality (odds ratio 1.59; 95% confidence interval 1.20, 2.10, p < .001) and reduction in ventilation-free days (95% confidence interval -1.24, -0.77, p < .001).

CONCLUSIONS

The changes in the clinical practice of mechanical ventilation in children in our institution reflect those reported for adults. In our experience, mortality among children with acute lung injury was reduced by 40%, and tidal volume was independently associated with reduced mortality and an increase in ventilation-free days.

[The prone position in acute respiratory distress syndrome: a critical systematic review]

OBJECTIVE

To do a critical systematic review regarding effects of prone positioning (PP) in patients with acute respiratory distress syndrome (ARDS).

METHODS

A systematic review (Highwire, Medline, Cochrane Library from 1976 to 2004), using the keywords: prone position, acute respiratory distress syndrome, allowed us to include the human studies on PP in ARDS patients, independantly of their objectives or their type of protocol. To appreciate the studies validity, we scored the quality evidence of the studies in order to grade our conclusions.

RESULTS AND CONCLUSION

The qualitative analysis of the 58 included studies (1,500 patients returned prone, 4,000 episodes of PP) led to the following main conclusions: 1) the PP improves oxygenation in the majority of ARDS patients (level of evidence I); 2) the PP improves the pulmonary haemodynamics without altering the systemic haemodynamics (level of evidence III); 3) the PP enhances the recruitment maneuvers (level of evidence III); 4) because there are no formal predictive criteria for response to the PP, a "trial of PP" or better two PP trials are necessary to look for the responders; 5) the PP should be performed as early as possible in the course of severe ARDS; 6) the optimal duration of PP is 18 to 23 hours daily, and it should be continued until improvement of arterial oxygenation, or loss of the positive effect of PP on arterial oxygenation or evidently patient's death.

Prone positioning can be safely performed in critically ill infants and children

OBJECTIVE

To describe the effects of prone positioning on airway management, mechanical ventilation, enteral nutrition, pain and sedation management, and staff utilization in infants and children with acute lung injury.

DESIGN

Secondary analysis of data collected in a multiple-center, randomized, controlled clinical trial of supine vs. prone positioning.

SETTING

Seven pediatric intensive care units located in the United States.

PATIENTS

One hundred and two pediatric patients (51 prone and 51 supine) with acute lung injury.

INTERVENTIONS

Patients randomized to the supine group remained supine. Patients randomized to the prone group were positioned prone per protocol during the acute phase of their illness for a maximum of 7 days. Both groups were managed using ventilator and sedation protocols and nutrition and skin care guidelines.

MEASUREMENTS AND MAIN RESULTS

Airway management and mechanical ventilatory variables before and after repositioning, enteral nutrition management, pain and sedation management, staff utilization, and adverse event data were collected for up to 28 days after enrollment. There were a total of 202 supine-prone-supine cycles. There were no differences in the incidence of endotracheal tube leak between the two groups (p = .30). Per protocol, 95% of patients remained connected to the ventilator during repositioning. The inadvertent extubation rate was 0.85 for the prone group and 1.03 for the supine group per 100 ventilator days (p = 1.00). There were no significant differences in the initiation of trophic (p = .24), advancing (p = .82), or full enteral feeds (p = .80) between the prone and supine groups; in the average pain (p = .81) and sedation (p = .18) scores during the acute phase; and in the amount of comfort medications received between the two groups (p = .91). There were no critical events during a turn procedure. While prone, two patients experienced an obstructed endotracheal tube. One patient, supported on high-frequency oscillatory ventilation, experienced persistent hypercapnea when prone and was withdrawn from the study. The occurrence of pressure ulcers was similar between the two groups (p = .71). Compared with the supine group, more staff (p </= .001) and more time were necessary to reposition patients in the prone group.

CONCLUSIONS

Our data show that prone positioning can be safely performed in critically ill pediatric patients and that these patients can be safely managed while in the prone position for prolonged periods of time.

Lung recruitment during mechanical positive pressure ventilation in the PICU: what can be learned from the literature?

A literature review was conducted to assess the evidence for recruitment manoeuvres used in conventional mechanical positive pressure ventilation. A total of 61 studies on recruitment manoeuvres were identified: 13 experimental, 31 ICU, 6 PICU and 12 anaesthesia studies. Recruitment appears to be a continuous process during inspiration and expiration and is determined by peak inspiratory pressure (PIP) and positive end expiratory pressure (PEEP). Single or repeated recruitment manoeuvres may result in a statistically significant increase in oxygenation; however, this is short lasting and clinically irrelevant, especially in late ARDS and pneumonia. Temporary PIP elevation may be effective but only after PEEP loss (for example disconnection and tracheal suctioning). Continuous PEEP elevation and prone positioning can increase P(a)O2 significantly. Adverse haemodynamic or barotrauma effects are reported in various studies. No data exist on the effect of recruitment manoeuvres on mortality, morbidity, length of stay or duration of mechanical ventilation. Although recruitment manoeuvres can improve oxygenation, they can potentially increase lung injury, which eventually determines outcome. Based on the presently available literature, prone position and sufficient PEEP as part of a lung protective ventilation strategy seem to be the safest and most effective recruitment manoeuvres. As paediatric physiology is essentially different from adult, paediatric studies are needed to determine the role of recruitment manoeuvres in the PICU.

Positioning for acute respiratory distress in hospitalised infants and children

BACKGROUND

Because of the association between prone positioning and sudden infant death syndrome SIDS) it is recommended that young infants be placed on their backs (supine). However, the supine position might not be the most appropriate position for infants and children hospitalised with acute respiratory distress. Positioning patients has been proposed as a non-invasive way of increasing oxygenation in adult patients with acute respiratory distress. But, because of substantial differences in respiratory mechanics between adults and children and the risk of SIDS in young infants, a specific review of positioning for infants and young children with acute respiratory distress is warranted.

OBJECTIVES

To compare the effects of different body positions in hospitalised infants and children with acute respiratory distress.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 3, 2004); MEDLINE (January 1966 to October Week 3, 2004); EMBASE (1980 to week 24, 2004); and CINAHL (1982 to October Week 3, 2004).

SELECTION CRITERIA

All randomised or systematically-allocated controlled clinical trials comparing two or more positions in the management of infants and children hospitalised with acute respiratory distress.

DATA COLLECTION AND ANALYSIS

Data were extracted from each study independently by two authors. Differences were resolved by consensus or referral to a third author. Continuous outcomes were analysed using a weighted mean difference and 95% confidence interval. No bivariate outcomes were available. All but one included study reported crossover data therefore this data was used for meta-analysis. Fixed-effect models were used unless heterogeneity was significant (p value equal to or less than 0.1), in which case a random-effects model was used.

MAIN RESULTS

Forty-nine papers were selected for this review of which 21 studies (22 publications) were included. These studies compared prone, supine, lateral, elevated, and flat positions. Prone positioning was significantly more beneficial than supine positioning in terms of oxygen saturation, partial pressure of arterial oxygen, oxygenation index, thoraco-abdominal synchrony, and episodes of desaturation. There were no statistically significant differences between any other positions.

AUTHORS' CONCLUSIONS

The prone position was significantly superior to the supine position in terms of oxygenation. However, as most patients included in the meta-analysis were ventilated, preterm infants the benefits of prone positioning may be most relevant to these infants. In addition, although placing infants and children in the prone position may improve respiratory function, the association of sudden infant death with prone positioning means that infants should only be placed in this position if continuous cardiorespiratory monitoring is used.

Acute lung injury and acute respiratory distress syndrome

Acute lung injury and acute respiratory distress syndrome are an important challenge for pediatric intensive care units. These disorders are characterized by a significant inflammatory response to a local (pulmonary) or remote (systemic) insult resulting in injury to alveolar epithelial and endothelial barriers of the lung, acute inflammation and protein rich pulmonary edema. The reported rates in children vary from 8.5 to 16 cases / 1000 pediatric intensive care unit (PICU) admissions. The pathological features of ARDS are described as passing through three overlapping phases - an inflammatory or exudative phase (0-7 days), a proliferative phase (7-21 days) and lastly a fibrotic phase (from day 10). The treatment of ARDS rests on good supportive care and control of initiating cause. The goal of ventilating patients with ALI/ARDS should be to maintain adequate gas exchange with minimal ventilator induced lung injury. This can be achieved by use of optimum PEEP, low tidal volume and appropriate FiO2. High frequency ventilation can improve oxygenation but does affect the outcomes. Prone positioning is a useful strategy to improve oxygenation. Pharmacological strategies have not made any significant impact on the outcomes. Preliminary data suggests some role for use of corticosteroids in non-resolving ARDS. The mortality rates have declined over the last decade chiefly due to the advances in supporting critically ill patients.

Approaches in the management of acute respiratory failure in children

PURPOSE OF REVIEW

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are conditions that are associated with significant morbidity and mortality in children. There have been no advances in preventing ARDS, but this review highlights strategies directed at minimizing ventilator-induced lung injury and other new adjunctive therapies in the care of these patients.

RECENT FINDINGS

High-frequency oscillatory ventilation, airway pressure release ventilation, and partial liquid ventilation are potential protective ventilatory modes for children with ALI or ARDS. Recruitment maneuvers, prone positioning, and kinetic therapy are all reported to improve oxygenation by opening the lung while positive end-expiratory pressure maintains functional residual capacity. Inhaled nitric oxide and surfactant are used to reduce inspired oxygen concentration and facilitate gas exchange, but their efficacy in ARDS continues to be investigated. Also, early investigations suggest that a specialized enteral formula can be a useful adjunctive therapy by reducing lung inflammation and improving oxygenation. When mechanical ventilation and adjunctive therapies fail, extracorporeal life support continues to be used as a rescue therapy.

SUMMARY

It is likely that a combination of these therapies will maximize treatment and clinical outcomes in the future, but the only way that will be proven is through large controlled clinical trials in pediatric patients.

Respostas fisiológicas da Posição Mãe-Canguru em bebês pré-termos, de baixo peso e ventilando espontaneamente

OBJETIVO: avaliar as respostas fisiológicas - freqüência cardíaca, saturação periférica de oxigênio, temperatura axilar e freqüência respiratória - em bebês pré-termos estáveis e em ventilação espontânea, submetidos à observação na incubadora e à Posição Mãe-Canguru. MÉTODOS: foram estudados 23 pré-termos estáveis hemodinamicamente, em ventilação espontânea, sem doença pulmonar diagnosticada, provenientes do Centro de Neonatologia do Hospital Conceição, Porto Alegre. Os pacientes foram distribuídos em Grupo I (incubadora) e Grupo II (Posição Mãe-Canguru) para um estudo de intervenção, de amostras pareadas, sendo cada paciente controle de si mesmo. Os dados foram registrados no primeiro minuto (T01), aos 30 (T30) e aos 60 minutos (T60). Utilizou-se o teste t de Student para comparação entre os grupos. RESULTADOS: os pacientes apresentaram uma média de idade gestacional de 34 semanas, média de peso pós-natal de 1780 g e mediana de 264 horas de vida. Observou-se um aumento estatisticamente significante na freqüência cardíaca em T30, na saturação de oxigênio em T30 e T60 e na temperatura axilar em T60, comparando o grupo da Posição Mãe-Canguru ao grupo controle. CONCLUSÕES: a Posição Mãe-Canguru promoveu aumento nos valores das respostas fisiológicas estudadas em pré-termos, quando instituída por uma hora, em comparação ao mesmo período na incubadora, sendo possível sua utilização durante atendimento fisioterapêutico.

Prone positioning of pediatric patients with ARDS results in improvement in oxygenation if maintained > 12 h daily

OBJECTIVES

To evaluate changes in oxygenation index (OI) in pediatric patients with ARDS during the first 24 h of prone positioning (PP), and to determine whether or not longer periods of PP (> 12 h) result in a more pronounced improvement in oxygenation.

DESIGN

A retrospective chart review of patients with ARDS who had been placed in PP for their management.

SETTING

Pediatric ICU of a children's hospital.

MEASUREMENTS AND MAIN RESULTS

We retrieved the charts of patients with ARDS who had been admitted to our pediatric ICU over a 3-year period and placed in PP for their management. The patients received mechanical ventilation, were sedated and pharmacologically paralyzed, and underwent arterial blood gas analysis, with concomitant documentation of ventilator settings, at a frequency of once every 4 h or more often. We divided the first 24 h of PP into two periods, brief and prolonged. The brief period was defined as duration of PP between 6 h and 10 h, and the prolonged period was between 18 h and 24 h. We compared pre-PP OI values to values after brief periods and prolonged periods of PP. Values of the PaO(2)/fraction of inspired oxygen (P/F) ratio and the mean airway pressure (MAP) were similarly evaluated. We also evaluated the degree of OI fluctuations during 24 h of PP by identifying the time points at which the best OI and the worst OI were observed. Data from a total of 40 pediatric patients with ARDS were evaluated. Twenty-one of the patients were male, and 19 were female; their ages ranged from 1 month to 18 years (mean +/- SD, 6.22 +/- 6.27 years). Thirty-two patients received conventional mechanical ventilation, and 8 patients received high-frequency oscillatory ventilation. Thirty-three patients survived, and 7 patients (21%) died. The mean duration of PP was 67 +/- 64 h (2.8 +/- 2.7 days), the mean number of ventilator days was 32 +/- 32, and the mean interval between endotracheal intubation and placing the patients in PP was 107 +/- 108 h (4.5 +/- 4.5 days). Thirty-seven patients completed 20 h of PP or more. The mean post-PP time points at which OI values were actually evaluated for these patients were 8 +/- 2 h (brief) and 21 +/- 4 h (prolonged), respectively. Overall, the OI decreased from a pre-PP value of 24.8 +/- 13.0 to 16.7 +/- 13.7 after a brief period of PP (p < 0.05 when compared to baseline) and 11.4 +/- 6.3 after prolonged period (p < 0.05 when compared to baseline and brief period values). This improvement in OI followed the improvement seen in the P/F ratio, whereas the MAP remained unchanged. The best mean OI value, with patients in PP, was 11 +/- 9 (p < 0.05 when compared to baseline) that occurred at 16 +/- 6 h, and the worst was 22 +/- 15 (p = not significant when compared to baseline) that occurred at 9 +/- 7 h.

CONCLUSIONS

PP of pediatric patients with ARDS for prolonged periods (18 to 24 h) results in a more pronounced and more stable reduction in their OI values than those observed after brief periods (6 to 10 h). This improvement in OI was not associated with changes in MAP during the first 24 h of mechanical ventilation. OI values tend to fluctuate more during the first 12 h of PP then they do during the subsequent 12 h.

Complications of intermittent prone positioning in pediatric patients receiving extracorporeal membrane oxygenation for respiratory failure

STUDY OBJECTIVE

To describe the safety and risks of placing pediatric patients in the prone position during extracorporeal membrane oxygenation (ECMO) for the treatment of respiratory failure.

DESIGN

Single-center retrospective cohort study.

SETTING

Tertiary pediatric ICUs.

PATIENTS

All patients admitted to the pediatric ICU who required ECMO for respiratory failure from 1995 to 2000.

INTERVENTIONS

None.

MEASUREMENTS AND RESULTS

Medical records for 93 patients representing 95 ECMO runs for treatment of respiratory failure were reviewed. Of these, 63 patients (66%) received intermittent prone positioning. Demographic data and clinical information were recorded. The median age was 12 months, and the median weight was 9.8 kg. There were 962 position changes. Complications surveyed for included bleeding from appliance insertion sites, appliance dislodgment, unplanned extubation, cutaneous pressure ulceration, corneal abrasion, and extreme hemodynamic instability. These complications were noted as to whether they were present prior to the initiation of prone positioning or whether they developed after prone positioning began. Twenty-four percent of patients had bleeding from cannulation sites prior to prone positioning, and 18% of patients had bleeding begin after prone positioning was initiated. Two patients had chest tubes dislodge after prone positioning began, but neither patient had bleeding occur or required reinsertion of the chest tube. There were no unplanned extubations, appliance displacements, development of cutaneous pressure ulcerations, or corneal abrasions associated with prone-positioning maneuvers. No patient had ECMO support removed secondary to the surveyed complications. Eighty-two percent of children who received prone positioning during ECMO for treatment of respiratory failure survived to hospital discharge.

CONCLUSION

We found that prone positioning may be used in pediatric ECMO patients without increasing the risk of complications. A multi-institutional, prospective, randomized, controlled study would better evaluate the efficacy of this practice and whether it is associated with a shorter length of ECMO or shorter post-ECMO ventilation and outcome.

Tratamientos complementarios: óxido nítrico, posición en prono y surfactante

The management of hypoxic respiratory failure is based on oxygen delivery and ventilatory support with lung-protective ventilation strategies. Better understanding of acute lung injury have led to new therapeutic approaches that can modify the outcome of these patients. These adjunctive oxygenation strategies include inhaled nitric oxide and surfactant delivery, and the use of prone positioning. Nitric oxide is a selective pulmonary vasodilator that when inhaled, improves oxygenation in clinical situations such as persistent pulmonary hypertension of the newborn, pulmonary hypertension associated with congenital heart disease, and acute respiratory distress syndrome (ARDS). When applied early in ARDS, prone positioning improves distribution of ventilation and reduces the intrapulmonary shunt. The surfactant has dramatically decreased mortality caused by hyaline membrane disease in premature newborns, although the results have been less successful in ARDS. Greater experience is required to determine whether the combination of these treatments will improve the prognosis of these patients.

Innovative practices of ventilatory support with pediatric patients

OBJECTIVES

The recognition that alveolar overdistension rather than peak inspiratory airway pressure is the primary determinant of lung injury has shifted our understanding of the pathogenesis of ventilator-induced side effects. In this review, contemporary ventilatory methods, supportive treatments, and future developments relevant to pediatric critical care are reviewed.

DATA SYNTHESIS

A strategy combining recruitment maneuvers, low-tidal volume, and higher positive end-expiratory pressure (PEEP) decreases barotrauma and volutrauma. Given that appropriate tidal volumes are critical in determining adequate alveolar ventilation and avoiding lung injury, volume-control ventilation with high PEEP levels has been proposed as the preferable protective ventilatory mode. Pressure-related volume control ventilation and high-frequency oscillatory ventilation (HFOV) have taken on an important role as protective lung strategies. Further data are required in the treatment of children, confirming the preliminary results in specific lung pathologies. Spontaneous breathing supported artificially during inspiration (pressure support ventilation) is widely used to maintain or reactivate spontaneous breathing and to avoid hemodynamic variation. Volume support ventilation reduces the need for manual adaptation to maintain stable tidal and minute volume and can be useful in weaning. Prone positioning and permissive hypercapnia have taken on an important role in the treatment of patients undergoing artificial ventilation. Surfactant and nitric oxide have been proposed in specific lung pathologies to facilitate ventilation and gas exchange and to reduce inspired oxygen concentration. Investigation of lung ventilation using a liquid instead of gas has opened new vistas on several lung pathologies with high mortality rates.

RESULTS

The conviction emerges that the best ventilatory treatment may be obtained by applying a combination of types of ventilation and supportive treatments as outlined above. Early treatment is important for the overall positive final result. Lung recruitment maneuvers followed by maintaining an open lung favor rapid resolution of pathology and reduce side effects.

CONCLUSIONS

The methods proposed require confirmation through large controlled clinical trials that can assess the efficacy reported in pilot studies and case reports and define the optimal method(s) to treat individual pathologies in the various pediatric age groups.

Management of the acute respiratory distress syndrome

Significant advances have occurred in the knowledge of the pathogenesis of ARDS. It is now recognized that ARDS is a manifestation of a diffuse process that results from a complicated cascade of events following an initial insult or injury. Mechanical ventilation and PEEP are still important components of supportive therapy. To avoid ventilator-associated lung injury there is emphasis on targeting ventilator management based on measurement of pulmonary mechanics. For those with resistant hypoxia and severe pulmonary hypertension adjunctive modalities, such as prone positioning and low-dose iNO, may provide important benefit. Alternative modes of supporting gas exchange, such as with partial liquid ventilation and extracorporeal gas-exchange, may serve as rescue therapies. Advances in cell and molecular biology have contributed to a better understanding of the role of inflammatory cells and mediators that contribute to the acute lung injury and the pathophysiology of the syndrome that manifests as ARDS. Based on this new understanding, the potential targets for intervention to ameliorate the systemic inflammatory response have proliferated. Examples include the cytokine network and its receptors, antioxidants, and endothelins. Apart from the challenge of testing these agents in experimental models, it seems likely that determination of the optimum combination of agents will become an equally important endeavor. A particular challenge is to develop better methods of predicting which of the many at-risk patients will go on to full-blown ARDS and MODS, thereby targeting subgroups of patients most likely to benefit from anti-inflammatory therapies. Similarly, the adverse effects of immunosuppressive therapy may be diminished by improved, perhaps molecular, techniques to detect microbial pathogens and permit differentiation between Systemic inflammatory response syndrome and sepsis.

Prone positioning does not affect cannula function during extracorporeal membrane oxygenation or continuous renal replacement therapy

INTRODUCTION

Prone positioning in respiratory failure has been shown to be a useful adjunct in the treatment of severe hypoxia. However, the prone position can result in dislodgment or malfunction of tubes and cannulae. Certain patients receiving extracorporeal membrane oxygenation (ECMO) or continuous renal replacement therapy (CRRT) may also benefit from positional therapy. The impact of cannula-related complications in these patients is potentially disastrous. The safety and efficacy of prone positioning of these patients has not been previously reported.

MATERIALS AND METHODS

A retrospective chart review evaluated ECMO or CRRT cannula location, and displacement or malfunction during positional change or while prone. The study was set in a General Surgery and Trauma Intensive Care Unit. The subjects were all patients at our institution who simultaneously underwent ECMO or CRRT and prone positioning from July 1996 to July 2001. There were no interventions.

RESULTS

Ten patients underwent ECMO and 42 patients underwent CRRT during the study period. Seven patients underwent simultaneous prone positioning and either ECMO (4/10) or CRRT (4/42). A total of 68 turning events (prone to supine or supine to prone) were recorded, with each patient averaging 9.7 (range, 4-16) turning episodes. Turning was performed with sheets and extra nursing personnel; no special mechanical assist devices were used. No patients experienced inadvertent cannula removal during turning. Two patients had poor flow through their cannulae. In one patient, this occurred in the supine position and required repositioning of the cannula. In the second patient, cannulae were changed twice and flow was poor in both the supine and the prone positions. All ECMO and CRRT patients received venous cannulae. Cannula location (seven internal jugular and 11 femoral) did not the affect risk of malfunction.

DISCUSSION AND CONCLUSIONS

Patients with venous cannulae for ECMO or CRRT can be safely placed in the prone position. Flow rates are maintained in this position. Potential cannula complications of ECMO and CRRT are not a contraindication to prone positioning in severely ill patients.

Lung salvage and protection ventilatory techniques

Physicians are in the beginning of an era in intensive care medicine in which they finally are starting to see improved outcomes in patients with AHRF. At the same time, intensivists are presented with a bewildering choice of ventilator options and adjunctive therapies. Trying to sort out which are "cosmetic," that is, improve the blood gases as opposed to influencing the outcome, remains a challenge and will be resolved only with additional RCTs. Principles of ventilator management that are driven by mimicking normal physiology are inappropriate and must be rethought.