Monitoring Dead Space in Mechanically Ventilated Children: Volumetric Capnography Versus Time-Based Capnography

Bhalla, Anoopindar; Rubin, Sarah; Newth, Christopher J L; Ross, Patrick; Morzov, Rica; Soto‐Campos, Gerardo; Khemani, Robinder G.

doi:10.4187/respcare.03892

Cited by 32 publications

(32 citation statements)

References 31 publications

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“…Furthermore, it is likely that fluctuations in alveolar dead space, rather than anatomic, are responsible for the association between dead space and mortality. As such, alveolar dead space as measured by AVDSf may actually be more sensitive to perturbations in physiology (14, 30). …”

Section: Discussionmentioning

confidence: 99%

Alveolar Dead Space Fraction Discriminates Mortality in Pediatric Acute Respiratory Distress Syndrome*

Yehya

Bhalla

Thomas

et al. 2016

Pediatric Critical Care Medicine

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Objective Physiologic dead space is associated with mortality in acute respiratory distress syndrome (ARDS), but its measurement is cumbersome. Alveolar dead space fraction (AVDSf) relies on the difference between arterial and end-tidal carbon dioxide (AVDSf = (PaCO2 − PETCO2)/PaCO2). We aimed to assess the relationship between AVDSf and mortality in a cohort of children meeting criteria for ARDS (both Berlin 2012 and AECC 1994 acute lung injury) and pediatric ARDS (PARDS, as defined by PALICC in 2015). Design Secondary analysis of a prospective, observational cohort. Setting Tertiary care, university affiliated pediatric intensive care unit. Patients Invasively ventilated children with PARDS. Interventions None. Measurements and Main Results Of the 283 children with PARDS, 266 had available PETCO2. AVDSf was lower in survivors (median 0.13 [IQR 0.06, 0.23]) than non-survivors (0.31 [0.19, 0.42], p < 0.001) at PARDS onset, but not 24 hours after (survivors 0.12 [0.06, 0.18], non-survivors 0.14 [0.06, 0.25], p=0.430). AVDSf at PARDS onset discriminated mortality with an area under receiver operating characteristic curve of 0.76 (95% CI 0.66–0.85, p < 0.001), better than either initial oxygenation index or PaO2/FIO2. In multivariate analysis, AVDSf at PARDS onset was independently associated with mortality, after adjustment for including severity of illness, immunocompromised status, and organ failures. Conclusions AVDSf at PARDS onset discriminates mortality, and is independently associated with non-survival. AVDSf represents a single, useful, readily obtained clinical biomarker reflective of pulmonary and non-pulmonary variables associated with mortality.

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Section: Discussionmentioning

confidence: 99%

Alveolar Dead Space Fraction Discriminates Mortality in Pediatric Acute Respiratory Distress Syndrome*

Yehya

Bhalla

Thomas

et al. 2016

Pediatric Critical Care Medicine

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“…End-tidal CO 2 was measured using the mainstream capnography sensor and cuvette according to the manufacturer’s manual. Dead space-to-tidal volume ratio was assessed by calculating the end-tidal alveolar dead space fraction (AVDSF) which has shown to be a good proxy [19]. …”

Section: Methodsmentioning

confidence: 99%

Short-term effects of neuromuscular blockade on global and regional lung mechanics, oxygenation and ventilation in pediatric acute hypoxemic respiratory failure

Wilsterman

Jager

Blokpoel

et al. 2016

Ann. Intensive Care

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BackgroundNeuromuscular blockade (NMB) has been shown to improve outcome in acute respiratory distress syndrome (ARDS) in adults, challenging maintaining spontaneous breathing when there is severe lung injury. We tested in a prospective physiological study the hypothesis that continuous administration of NMB agents in mechanically ventilated children with severe acute hypoxemic respiratory failure (AHRF) improves the oxygenation index without a redistribution of tidal volume V T toward non-dependent lung zones.MethodsOxygenation index, PaO2/FiO2 ratio, lung mechanics (plateau pressure, mean airway pressure, respiratory system compliance and resistance), hemodynamics (heart rate, central venous and arterial blood pressures), oxygenation [oxygenation index (OI), PaO2/FiO2 and SpO2/FiO2], ventilation (physiological dead space-to-V T ratio) and electrical impedance tomography measured changes in end-expiratory lung volume (EELV), and V T distribution was measured before and 15 min after the start of continuous infusion of rocuronium 1 mg/kg. Patients were ventilated in a time-cycled, pressure-limited mode with pre-set V T. All ventilator settings were not changed during the study.ResultsTwenty-two patients were studied (N = 18 met the criteria for pediatric ARDS). Median age (25–75 interquartile range) was 15 (7.8–77.5) weeks. Pulmonary pathology was present in 77.3%. The median lung injury score was 9 (8–10). The overall median CoV and regional lung filling characteristics were not affected by NMB, indicating no ventilation shift toward the non-dependent lung zones. Regional analysis showed a homogeneous time course of lung inflation during inspiration, indicating no tendency to atelectasis after the introduction of NMB. NMB decreased the mean airway pressure (p = 0.039) and OI (p = 0.039) in all patients. There were no significant changes in lung mechanics, hemodynamics and EELV. Subgroup analysis showed that OI decreased (p = 0.01) and PaO2/FiO2 increased (p = 0.02) in patients with moderate or severe PARDS.ConclusionsNMB resulted in an improved oxygenation index in pediatric patients with AHRF. Distribution of V T and regional lung filling characteristics were not affected.

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“…Volumetric capnography is the best capnography method to guide ventilatory support according to V D fractions, but it requires specialized and expensive equipment. As evidenced by Bhalla et al, 26 timebased capnography may be a feasible and less expensive option to assess alveolar V D during mechanical ventilation in the ICU and reduce it, allowing a better V /Q match. Despite its potential, capnography remains rarely used because health professionals are unaware of its usefulness in the bedside routine.…”

mentioning

confidence: 99%

“…24,25 Furthermore, volumetric capnography can discriminate healthy individuals from those with lung disease, such as cystic fibrosis, bronchiectasis, COPD, lung fibrosis, and asthma, which presents a steeper slope of phase 3 of the capnogram. [9][10][11] In this issue of RESPIRATORY CARE, Bhalla et al 26 The interpretation of capnography must take into account the stability of physiologic variables, such as minute ventilation, V T , cardiac output, and CO 2 body storage. As a result, the evaluation and interpretation of capnographic data in children should be cautious, particularly in a critical care setting.…”

mentioning

confidence: 99%

“…Although the authors have described that data collection was made during a stable period, if capnography data had been recorded in a similar ventilation mode, bias could be reduced. Bhalla et al 26 To summarize, capnography is promising and feasible in the ICU, emergency room, and anesthesia care unit for monitoring the lungs' ventilation/perfusion in mechanically ventilated patients. Volumetric capnography is the best capnography method to guide ventilatory support according to V D fractions, but it requires specialized and expensive equipment.…”

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confidence: 99%

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Capnography: A Feasible Tool in Clinical and Experimental Settings

Oliveira

Moreira

2015

Respir Care

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Monitoring Dead Space in Mechanically Ventilated Children: Volumetric Capnography Versus Time-Based Capnography

Cited by 32 publications

References 31 publications

Alveolar Dead Space Fraction Discriminates Mortality in Pediatric Acute Respiratory Distress Syndrome*

Alveolar Dead Space Fraction Discriminates Mortality in Pediatric Acute Respiratory Distress Syndrome*

Short-term effects of neuromuscular blockade on global and regional lung mechanics, oxygenation and ventilation in pediatric acute hypoxemic respiratory failure

Capnography: A Feasible Tool in Clinical and Experimental Settings

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