Dead Space Ventilation in Critically Ill Children With Lung Injury

doi:10.1378/chest.123.6.2050

Chest

Volume 123, Issue 6, June 2003, Pages 2050-2056

https://doi.org/10.1378/chest.123.6.2050 Get rights and content

Study objective

In children with acute lung injury, there is an increase in minute ventilation ( $\dot{V}$ e) and inefficient gas exchange due to a high level of physiologic dead space ventilation (Vd/Vt). Mechanical ventilation with positive end-expiratory pressure, when used in critically ill patients to correct hypoxemia, may contribute to increased Vd/Vt. The purpose of this study was to measure metabolic parameters and Vd/Vt in critically ill children.

Design

A cross-sectional study.

Setting

Pediatric ICU of a university hospital.

Patients

A total of 45 mechanically intubated children (mean age, 5.5 years).

Interventions

Indirect calorimetry was used to measure metabolic parameters. Vd/Vt parameters were calculated using the modified Bohr-Enghoff equation. ARDS was defined based on criteria by The American-European Consensus Conference.

Measurements and results

The group mean (± SD) ventilatory equivalent for oxygen (VeqO₂) and ventilatory equivalent for carbon dioxide (VeqCO₂) were 2.9 ± 1 and 3.3 ± 1 L per 100 mL, respectively. The group mean Vd/Vt was 0.48 ± 0.2. When compared to non-ARDS patients (33 patients), the patients with ARDS (12 patients) had a significantly higher VeqO₂ (3.3 ± 1 vs 2.8 ± 1 L per 100 mL, respectively; p < 0.05), a significantly higher VeqCO₂ (3.7 ± 1 L/100 vs 3.1 ± 1 L per 100 mL, respectively; p < 0.05), and a significantly higher Vd/Vt (0.62 ± 0.14 vs 0.43 ± 0.15, respectively; p < 0.0005).

Conclusions

Critically ill children with ARDS have increased Vd/Vt. Increased Vd/Vt was the main cause of the excess of $\dot{V}$ e demand in these patients. Increased metabolic demands, as shown by the VeqO₂, VeqCO₂, and ventilatory support, are the major determinants of $\dot{V}$ e requirements in children with ARDS.

Section snippets

Materials and Methods

This cross-sectional study measured metabolic and Vd/Vt parameters in 45 critically ill children who had been admitted to a pediatric ICU. The protocol was approved by the institutional review board for studies involving human subjects, and informed parental consent was obtained before the study.

While receiving mechanical ventilation, a previously validated mass spectrometer for children was used to measure metabolic parameters by using a breath-by-breath technique of indirect calorimetry.³⁴

Results

Forty-five patients (20 female patients and 25 male patients) participated in the study. The mean age of the patients was 5.5 ± 5.4 years (range, 0.25 to 18 years), and the mean weight was 19 ± 14 kg (range, 4 to 55 kg). The patient’s clinical diagnoses included the following: sepsis (10 patients); bacterial pneumonia (14 patients); viral pneumonia (6 patients); postoperative (8 patients); malignancies (5 patients); and Stevens-Johnson syndrome (2 patients). The mean length of stay in the ICU

Discussion

The purpose of this study was to measure the metabolic and Vd/Vt parameters in critically ill children and to assess the effect of lung injury on Vd/Vt in children on mechanical ventilation.

Several studies⁶¹⁰¹³have reported Vd/Vt results in mechanically ventilated preoperative adult patients, with values ranging from 0.31 to 0.36. The values reported in pediatric preoperative patients have ranged from 0.35 to 0.38.²⁷²⁹³⁰It has been described that patients with ARDS, sepsis, and trauma require

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Le syndrome de détresse respiratoire aiguë (SDRA) est une insuffisance respiratoire aiguë hypoxémiante rapidement progressive par comblement alvéolaire liée à une altération de la barrière alvéolocapillaire suite à une agression pulmonaire directe ou indirecte. Beaucoup moins fréquent en pédiatrie qu’à l’âge adulte, les pédiatres réanimateurs ont longtemps dû extrapoler les recommandations faites pour l’adulte pour leur pratique clinique quotidienne. En 2015, les experts de la Pediatric Acute Lung Injury Consensus Conference (PALICC) ont publié les premières recommandations internationales spécifiquement dédiées au SDRA de l’enfant. Après une synthèse de l’évolution de la définition du SDRA depuis sa première description en 1967, nous proposons de détailler les principales recommandations tant diagnostiques que thérapeutiques de la PALICC.
Acute respiratory distress syndrome (ARDS) is a rapidly progressive hypoxemic respiratory insufficiency induced by alveolar filling mainly caused by alveolocapillary wall disruption, following direct or indirect pulmonary injury. Much less frequent in children than in adults, pediatric intensivists had long applied adult guidelines to their daily practice. In 2015, experts from the Pediatric Acute Lung Injury Consensus Conference (PALICC) published the first international guidelines specifically dedicated to pediatric ARDS. After a short summary of the history of the ARDS definition since its first report in 1967, we describe the main diagnostic and therapeutic guidelines for PALICC.
Acute respiratory distress syndrome in childhood: Changing definition and news from the Pediatric Consensus Conference
2017, Archives de Pediatrie
Le syndrome de détresse respiratoire aiguë (SDRA) est une insuffisance respiratoire aiguë hypoxémiante rapidement progressive par comblement alvéolaire liée à une altération de la barrière alvéolocapillaire suite à une agression pulmonaire directe ou indirecte. Beaucoup moins fréquent en pédiatrie qu’à l’âge adulte, les pédiatres réanimateurs ont longtemps dû extrapoler les recommandations faites pour l’adulte pour leur pratique clinique quotidienne. En 2015, les experts de la Pediatric Acute Lung Injury Consensus Conference (PALICC) ont publié les premières recommandations internationales spécifiquement dédiées au SDRA de l’enfant. Après une synthèse de l’évolution de la définition du SDRA depuis sa première description en 1967, nous proposons de détailler les principales recommandations tant diagnostiques que thérapeutiques de la PALICC.
Acute respiratory distress syndrome (ARDS) is a rapidly progressive hypoxemic respiratory insufficiency induced by alveolar filling mainly caused by alveolocapillary wall disruption, following direct or indirect pulmonary injury. Much less frequent in children than in adults, pediatric intensivists had long applied adult guidelines to their daily practice. In 2015, experts from the Pediatric Acute Lung Injury Consensus Conference (PALICC) published the first international guidelines specifically dedicated to pediatric ARDS. After a short summary of the history of the ARDS definition since its first report in 1967, we describe the main diagnostic and therapeutic guidelines for PALICC.
Respiratory monitoring of pediatric patients in the Intensive Care Unit
2016, Boletin Medico del Hospital Infantil de Mexico
La monitorización respiratoria representa un importante rol en el cuidado del niño con falla respiratoria aguda. Por tanto, su apropiado uso y correcta interpretación (reconociendo qué señales y variables deben ser priorizadas) deberían ayudar a un mejor entendimiento de la fisiopatología de la enfermedad y de los efectos de las intervenciones terapéuticas. Asimismo, la monitorización del paciente ventilado permite, entre otras determinaciones, evaluar diversos parámetros de la mecánica respiratoria, conocer el estado de los diferentes componentes del sistema respiratorio y guiar los ajustes de la terapia ventilatoria.
En esta actualización se describe la utilidad de diversas técnicas de monitorización respiratoria (incluyendo métodos convencionales y otros más recientes), se definen conceptos básicos de mecánica ventilatoria, su interpretación y cómo el adecuado análisis de la información puede ocasionar un impacto en el manejo clínico del paciente.
Respiratory monitoring plays an important role in the care of children with acute respiratory failure. Therefore, its proper use and correct interpretation (recognizing which signals and variables should be prioritized) should help to a better understanding of the pathophysiology of the disease and the effects of therapeutic interventions. In addition, ventilated patient monitoring, among other determinations, allows to evaluate various parameters of respiratory mechanics, know the status of the different components of the respiratory system and guide the adjustments of ventilatory therapy.
In this update, the usefulness of several techniques of respiratory monitoring including conventional respiratory monitoring and more recent methods are described. Moreover, basic concepts of mechanical ventilation, their interpretation and how the appropriate analysis of the information obtained can cause an impact on the clinical management of the patient are defined.
Pulmonary Edema
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Ventilator strategies - What monitoring is helpful?
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Adaptive support ventilation: An appropriate mechanical ventilation strategy for acute respiratory distress syndrome?
2009, Anesthesiology
Adaptive support ventilation (ASV) allows the clinician to set a maximum plateau pressure (PP) and automatically adjusts tidal volume to keep PP below the set maximum.
ASV was compared to a fixed tidal volume of 6 ml/kg. ASV determined the respiratory rate and tidal volume based on its algorithms. Maximum airway pressure limit was 28 cm H₂O in ASV. Six sets of lung mechanics were simulated for two ideal body weights: 60 kg, Group I; 80 kg, Group II. Positive end expiratory pressure was 8, 12, and 16 cm H₂O, and target minute volume 120%, 150%, and 200% of predicted minute volume.
ASV “sacrificed” tidal volume and minute ventilation to maintain PP in 9 (17%) of 54 scenarios in Group I and 20 (37%) of 54 scenarios in Group II. In Group I, the number of scenarios with PP of 28 cm H₂O or more was 14 for ASV (26%) and 19 for 6 ml/kg (35%). In these scenarios, mean PP were ASV 28.8 ± 0.86 cm H₂O (min 28, max 30.3) and 6 ml/kg 33.01 ± 3.48 cm H₂O (min 28, max 37.8) (P = 0.000). In group II, the number of scenarios PP of 28 cm H₂O or more was 10 for ASV (19%) and 21 for 6 ml/kg (39%). In these cases, mean PP values were ASV 28.78 ± 0.54 cm H₂O (min 28, max 29.6) and 6 ml/kg 32.66 ± 3.37 cm H₂O (min 28.2, max 38.2) (P = 0.000).
In a lung model with varying mechanics, ASV is better able to prevent the potential damaging effects of excessive PP (greater than 28 cm H₂O) than a fixed tidal volume of 6 ml/kg by automatically adjusting airway pressure, resulting in a decreased tidal volume.

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Reproduction of this article is prohibited without written permission from the American College of Chest Physicians (e-mail: [email protected]).

This research was supported by the National Institutes of Health General Clinical Research Center and by the Genevieve R. McClelland Fund for Pediatric Intensive Care Research.

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Chest

Clinical Investigations in Critical CareDead Space Ventilation in Critically Ill Children With Lung Injurya

Study objective

Design

Setting

Patients

Interventions

Measurements and results

Conclusions

Section snippets

Materials and Methods

Results

Discussion

Lancet

Chest

Chest

Br J Anaesth

Am J Clin Nutr

Nutrition

Br J Anaesth

Br J Anaesth

The effects of expiratory positive airway pressure on the resolution of oleic acid-induced lung injury in dogs

Am Rev Respir Dis

Early application of positive end-expiratory pressure in patients at risk for the adult respiratory-distress syndrome

N Engl J Med

Alterations of lung and chest wall mechanics in patients with acute lung injury: effects of positive end-expiratory pressure

Am J Respir Crit Care Med

Current concepts: positive end-expiratory pressure in adult respiratory failure

N Engl J Med

Some recent advances in the study of the control of breathing in patients with chronic obstructive lung disease

Anesth Analg

Dead space during artificial ventilation: gas compression and mechanical dead space

J Appl Physiol

Deadspace during anaesthesia

Acta Anaesthesiol Scand Suppl

Physiological dead space and arterial to end-tidal CO2 difference under controlled normocapnic ventilation in young anaesthetised subjects

Indian J Med Res

Change in Paco2with mechanical dead space during artificial ventilation

J Appl Physiol

The influence of CO2production and physiological deadspace on end-tidal CO2 during controlled ventilation: a study using a mechanical model

Anaesth Intensive Care

Effect of tidal volume on gas exchange and oxygen transport in the adult respiratory distress syndrome

Am Rev Respir Dis

Ventilation-perfusion distributions in the adult respiratory distress syndrome

Am Rev Respir Dis

Distribution of ventilation and perfusion during positive end-expiratory pressure in the adult respiratory distress syndrome

Am Rev Respir Dis

Physiological effects of reduced tidal volume at constant minute ventilation and inspiratory flow rate in acute respiratory distress syndrome

Intensive Care Med

Early bedside detection of pulmonary vascular occlusion during acute respiratory failure

Am Rev Respir Dis

Alterations of the gas exchange apparatus in adult respiratory insufficiency associated with septicemia

Am Rev Respir Dis

Clinical Investigations in Critical Care
Dead Space Ventilation in Critically Ill Children With Lung Injury^a

Change in Paco₂with mechanical dead space during artificial ventilation

The influence of CO₂production and physiological deadspace on end-tidal CO2 during controlled ventilation: a study using a mechanical model