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[PMID]:29040312
[Au] Autor:Lin HJ; Huang CT; Hsiao HF; Chiang MC; Jeng MJ
[Ad] Endereço:Department of Respiratory Therapy, Chang Gung Memorial Hospital, Taoyuan, Taiwan.
[Ti] Título:End-tidal carbon dioxide measurement in preterm infants with low birth weight.
[So] Source:PLoS One;12(10):e0186408, 2017.
[Is] ISSN:1932-6203
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:OBJECTIVE: There are conflicting data regarding the use of end-tidal carbon dioxide (PetCO2) measurement in preterm infants. The aim of this study was to evaluate the effects of different dead space to tidal volume ratios (VD/VT) on the correlation between PetCO2 and arterial carbon dioxide pressure (PaCO2) in ventilated preterm infants with respiratory distress syndrome (RDS). METHODS: We enrolled ventilated preterm infants (with assist control mode or synchronous intermittent mandatory mode) with RDS who were treated with surfactant in this prospective study. Simultaneous PetCO2 and PaCO2 data pairs were obtained from ventilated neonates monitored using mainstream capnography. Data obtained before and after surfactant treatment were also analyzed. RESULTS: One-hundred and one PetCO2 and PaCO2 pairs from 34 neonates were analyzed. There was a moderate correlation between PetCO2 and PaCO2 values (r = 0.603, P < 0.01). The correlation was higher in the post-surfactant treatment group (r = 0.786, P < 0.01) than the pre-surfactant treatment group (r = 0.235). The values of PaCO2 and PetCO2 obtained based on the treatment stage of surfactant therapy were 42.4 ± 8.6 mmHg and 32.6 ± 7.2 mmHg, respectively, in pre-surfactant treatment group, and 37.8 ± 10.3 mmHg and 33.7 ± 9.3 mmHg, respectively, in the post-surfactant treatment group. Furthermore, we found a significant decrease in VD/VT in the post-surfactant treatment group when compared to the pre-surfactant treatment group (P = 0.003). CONCLUSIONS: VD/VT decreased significantly after surfactant therapy and the correlation between PetCO2 and PaCO2 was higher after surfactant therapy in preterm infants with RDS.
[Mh] Termos MeSH primário: Dióxido de Carbono/análise
Surfactantes Pulmonares/uso terapêutico
Síndrome do Desconforto Respiratório do Recém-Nascido/diagnóstico
Síndrome do Desconforto Respiratório do Recém-Nascido/terapia
[Mh] Termos MeSH secundário: Gasometria
Dióxido de Carbono/metabolismo
Feminino
Idade Gestacional
Seres Humanos
Recém-Nascido de Baixo Peso
Recém-Nascido
Recém-Nascido Prematuro
Masculino
Monitorização Fisiológica
Pressão Parcial
Estudos Prospectivos
Respiração Artificial
Espaço Morto Respiratório/fisiologia
Síndrome do Desconforto Respiratório do Recém-Nascido/fisiopatologia
Volume de Ventilação Pulmonar/fisiologia
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Pulmonary Surfactants); 142M471B3J (Carbon Dioxide)
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171031
[Lr] Data última revisão:
171031
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:171018
[St] Status:MEDLINE
[do] DOI:10.1371/journal.pone.0186408


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[PMID]:28223465
[Au] Autor:Bourgoin P; Baudin F; Brossier D; Emeriaud G; Wysocki M; Jouvet P
[Ad] Endereço:Pediatric Intensive Care Unit, Hopital Femme-Enfant-Adolescent, Centre Hospitalier Universitaire de Nantes, Nantes, France. pierre.bourgoin@chu-nantes.fr.
[Ti] Título:Assessment of Bohr and Enghoff Dead Space Equations in Mechanically Ventilated Children.
[So] Source:Respir Care;62(4):468-474, 2017 Apr.
[Is] ISSN:1943-3654
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:BACKGROUND: Recent findings suggest that using alveolar P (P ) estimated by volumetric capnography in the Bohr equation instead of P (Enghoff modification) could be appropriate for the calculation of physiological dead space to tidal volume ratio (V /V and V /V , respectively). We aimed to describe the relationship between these 2 measurements in mechanically ventilated children and their significance in cases of ARDS. METHODS: From June 2013 to December 2013, mechanically ventilated children with various respiratory conditions were included in this study. Demographic data, medical history, and ventilatory parameters were recorded. Volumetric capnography indices (NM3 monitor) were obtained over a period of 5 min preceding a blood sample. Bohr's and Enghoff's dead space, S2 and S3 slopes, and the S2/S3 ratio were calculated breath-by-breath using dedicated software (FlowTool). This study was approved by Ste-Justine research ethics review board. RESULTS: Thirty-four subjects were analyzed. Mean V /V was 0.39 ± 0.12, and V /V was 0.47 ± 0.13 ( = .02). The difference between V /V and V /V was correlated with P /F and with S2/S3. In subjects without lung disease (P /F ≥ 300), mean V /V was 0.36 ± 0.11, and V /V was 0.39 ± 0.11 ( = .056). Two children with status asthmaticus had a major difference between V /V and V /V in the absence of a low P /F . CONCLUSIONS: This study suggests that V /V and V /V are not different when there is no hypoxemia (P /F > 300) except in the case of status asthmaticus. In subjects with a low P /F , the method to measure V /V must be reported, and results cannot be easily compared if the measurement methods are not the same.
[Mh] Termos MeSH primário: Capnografia/estatística & dados numéricos
Respiração Artificial/estatística & dados numéricos
Espaço Morto Respiratório
Síndrome do Desconforto Respiratório do Adulto/fisiopatologia
Volume de Ventilação Pulmonar
[Mh] Termos MeSH secundário: Capnografia/métodos
Estudos de Casos e Controles
Criança
Pré-Escolar
Feminino
Seres Humanos
Masculino
Modelos Teóricos
Monitorização Fisiológica/métodos
Monitorização Fisiológica/estatística & dados numéricos
Síndrome do Desconforto Respiratório do Adulto/terapia
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171016
[Lr] Data última revisão:
171016
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170223
[St] Status:MEDLINE
[do] DOI:10.4187/respcare.05108


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[PMID]:28040384
[Au] Autor:Gazmuri RJ; Patel DJ; Stevens R; Smith S
[Ad] Endereço:Section of Critical Care Medicine, Captain James A. Lovell Federal Health Care Center, North Chicago, IL, United States; Resuscitation Institute, Rosalind Franklin University of Medicine and Science, North Chicago, IL, United States. Electronic address: raul.gazmuri@rosalindfranklin.edu.
[Ti] Título:Circulatory collapse, right ventricular dilatation, and alveolar dead space: A triad for the rapid diagnosis of massive pulmonary embolism.
[So] Source:Am J Emerg Med;35(6):936.e1-936.e4, 2017 Jun.
[Is] ISSN:1532-8171
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:A triad of circulatory collapse, right ventricular dilatation, and large alveolar dead space is proposed for the rapid diagnosis and treatment of massive pulmonary embolism. A 17year-old female on oral contraceptives collapsed at home becoming incoherent with shallow breathing. Paramedics initiated mechanical chest compression and transported the patient to our emergency department, arriving minimally responsive with undetectable blood pressure but having positive corneal reflexes and bradycardia with wide QRS. The trachea was intubated and goal-directed echocardiography revealed marked right ventricular dilatation with septal flattening. The arterial PCO was 40mmHg with an end-tidal PCO of 8mmHg, revealing a large alveolar dead space. Persistent hypotension, bradycardia, and fading alertness despite epinephrine and norepinephrine infusions prompted resumption of chest compression. Intravenous alteplase (10mg bolus over 10min followed by 90mg over 110min) begun 125min after collapse improved hemodynamic function within 10min allowing discontinuation of chest compression. Five and a half hours after starting alteplase, the patient was hemodynamically stable and had normal end-tidal PCO . A CT-angiogram showed the pulmonary arteries free of emboli but a thrombus in the right common iliac vein. The patient recovered fully and was discharged home on warfarin 8days later. Based on this and other reports, we propose a triad of circulatory collapse, right ventricular dilatation, and large alveolar dead space for the rapid diagnosis and treatment of massive pulmonary embolism, with systemic fibrinolysis as the first-line intervention.
[Mh] Termos MeSH primário: Embolia Pulmonar/diagnóstico
Espaço Morto Respiratório
Choque/diagnóstico por imagem
Disfunção Ventricular Direita/diagnóstico por imagem
[Mh] Termos MeSH secundário: Adolescente
Angiografia por Tomografia Computadorizada
Dilatação
Ecocardiografia
Eletrocardiografia
Feminino
Fibrinolíticos/administração & dosagem
Hemodinâmica
Seres Humanos
Embolia Pulmonar/tratamento farmacológico
Ativador de Plasminogênio Tecidual/administração & dosagem
Varfarina
[Pt] Tipo de publicação:CASE REPORTS; JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Fibrinolytic Agents); 5Q7ZVV76EI (Warfarin); EC 3.4.21.68 (Tissue Plasminogen Activator)
[Em] Mês de entrada:1708
[Cu] Atualização por classe:170803
[Lr] Data última revisão:
170803
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170102
[St] Status:MEDLINE


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[PMID]:28003557
[Au] Autor:Vianna JR; Pires Di Lorenzo VA; Simões MM; Jamami M
[Ad] Endereço:Claretiano Centro Universitário, Santa Casa of Misericórdia Hospital, Batatais, São Paulo, Brazil. jacrfvianna@uol.com.br.
[Ti] Título:Comparing the Effects of Two Different Levels of Hyperoxygenation on Gas Exchange During Open Endotracheal Suctioning: A Randomized Crossover Study.
[So] Source:Respir Care;62(1):92-101, 2017 Jan.
[Is] ISSN:1943-3654
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:BACKGROUND: Endotracheal suctioning is required for mechanically ventilated patients to maintain a patent airway. Studies show that open endotracheal suctioning affects respiratory mechanics and gas exchange. The aim of this study was to compare the effectiveness of hyperoxygenation with F + 0.20 above baseline and hyperoxygenation with F 1.0 in preventing hypoxemia, and to determine the impact of open endotracheal suctioning on the pulmonary ventilation of critical subjects receiving mechanical ventilatory support. METHODS: This prospective randomized crossover study was conducted in the ICU. Sixty-eight mechanically ventilated subjects with F ≤ 0.6 and requiring endotracheal suctioning were included in this study. Open endotracheal suctioning was performed using 2 different intervention sequences: hyperoxygenation of 0.20 above baseline F (F + 0.20) and 1.0 hyperoxygenation (F 1.0). Oxygenation was assessed via oxygen saturation as measured by pulse oximetry (S ), and changes in lung ventilation were measured via alveolar gas volume (V̇ ), alveolar minute volume (V̇ ), carbon dioxide (CO ) production (V̇ ), mixed exhaled partial pressure of CO (P ), exhaled tidal CO volume (V CO ), end-tidal CO (P ), anatomical dead space to tidal volume ratio (V /V ), and anatomical dead space volume of each breath (V ) using volumetric capnography, and breathing frequency (f), heart rate, and mean arterial pressure using a multiparameter monitor. RESULTS: S levels were significantly higher within interventions (F + 0.20 and 1.0) 1 min before and after suction. Also, there was a significant increase in P , P , heart rate, and mean arterial pressure immediately after the procedure compared with baseline, and in V CO , only for F + 0.20. Baseline values were not found to be significantly different between the groups in case of any dependent variable. CONCLUSIONS: In mechanically ventilated adult subjects, hyperoxygenation with F + 0.20 above baseline prevents hypoxemia. Also, transient changes in pulmonary ventilation with open circuit suctioning were confirmed by volumetric capnography analysis. (Trial registration: ClinicalTrials.gov NCT02440919).
[Mh] Termos MeSH primário: Dióxido de Carbono/metabolismo
Hipóxia/prevenção & controle
Oxigênio/administração & dosagem
Troca Gasosa Pulmonar
Respiração Artificial
[Mh] Termos MeSH secundário: Idoso
Idoso de 80 Anos ou mais
Pressão Arterial
Capnografia
Dióxido de Carbono/análise
Estudos Cross-Over
Feminino
Frequência Cardíaca
Seres Humanos
Intubação Intratraqueal
Masculino
Meia-Idade
Oximetria
Oxigênio/sangue
Estudos Prospectivos
Ventilação Pulmonar
Espaço Morto Respiratório/fisiologia
Taxa Respiratória
Método Simples-Cego
Sucção
Volume de Ventilação Pulmonar
Traqueia
[Pt] Tipo de publicação:COMPARATIVE STUDY; JOURNAL ARTICLE; RANDOMIZED CONTROLLED TRIAL
[Nm] Nome de substância:
142M471B3J (Carbon Dioxide); S88TT14065 (Oxygen)
[Em] Mês de entrada:1709
[Cu] Atualização por classe:170929
[Lr] Data última revisão:
170929
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:161223
[Cl] Clinical Trial:ClinicalTrial
[St] Status:MEDLINE
[do] DOI:10.4187/respcare.04665


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[PMID]:27515984
[Au] Autor:Hurley EH; Keszler M
[Ad] Endereço:Department of Pediatrics, Women and Infants, Warren Alpert Medical School of Brown University, Providence, Rhode Island, USA.
[Ti] Título:Effect of inspiratory flow rate on the efficiency of carbon dioxide removal at tidal volumes below instrumental dead space.
[So] Source:Arch Dis Child Fetal Neonatal Ed;102(2):F126-F130, 2017 Mar.
[Is] ISSN:1468-2052
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:OBJECTIVE: The ability to ventilate babies with tidal volumes (V s) below dead space has been demonstrated both in vivo and in vitro, though it appears to violate classical respiratory physiology. We hypothesised that this phenomenon is made possible by rapid flow of gas that penetrates the dead space allowing fresh gas to reach the lungs and that the magnitude of this phenomenon is affected by flow rate or how rapidly air flows through the endotracheal tube. METHODS: We conducted two bench experiments. First, we measured the time needed for complete CO washout from a test lung to assess how fixed V but different inflation flow rates affect ventilation. For the second experiment, we infused carbon dioxide at a low rate into the test lung, varied the inflation flow rate and adjusted the V to maintain stable end tidal carbon dioxide (ETCO ). RESULTS: At all tested V s, lower flow rate increased the time it took for CO to washout from the test lung. The effect was most pronounced for V s below dead space. The CO steady-state experiment showed that ETCO increased when the flow rate decreased. Ventilating with a slower flow rate required a nearly 20% increase in V for the same effective alveolar ventilation. CONCLUSIONS: Inflation flow rate affects the efficiency of CO removal with low V . Our results are relevant for providers using volume-controlled ventilation or other modes that use low inflation flow rates because the V required for normocapnia will be higher than published values that were generated using pressure-limited ventilation modes with high inflation flows.
[Mh] Termos MeSH primário: Pulmão/fisiologia
Troca Gasosa Pulmonar/fisiologia
Respiração Artificial/métodos
Espaço Morto Respiratório/fisiologia
Volume de Ventilação Pulmonar/fisiologia
[Mh] Termos MeSH secundário: Dióxido de Carbono/fisiologia
Seres Humanos
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
142M471B3J (Carbon Dioxide)
[Em] Mês de entrada:1704
[Cu] Atualização por classe:170420
[Lr] Data última revisão:
170420
[Sb] Subgrupo de revista:AIM; IM
[Da] Data de entrada para processamento:160813
[St] Status:MEDLINE
[do] DOI:10.1136/archdischild-2015-309636


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[PMID]:27334879
[Au] Autor:Verscheure S; Massion PB; Verschuren F; Damas P; Magder S
[Ad] Endereço:Department of Critical Care Medicine, University of McGill, Montreal, Quebec, Canada.
[Ti] Título:Volumetric capnography: lessons from the past and current clinical applications.
[So] Source:Crit Care;20(1):184, 2016 06 23.
[Is] ISSN:1466-609X
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Dead space is an important component of ventilation-perfusion abnormalities. Measurement of dead space has diagnostic, prognostic and therapeutic applications. In the intensive care unit (ICU) dead space measurement can be used to guide therapy for patients with acute respiratory distress syndrome (ARDS); in the emergency department it can guide thrombolytic therapy for pulmonary embolism; in peri-operative patients it can indicate the success of recruitment maneuvers. A newly available technique called volumetric capnography (Vcap) allows measurement of physiological and alveolar dead space on a regular basis at the bedside. We discuss the components of dead space, explain important differences between the Bohr and Enghoff approaches, discuss the clinical significance of arterial to end-tidal CO2 gradient and finally summarize potential clinical indications for Vcap measurements in the emergency room, operating room and ICU.
[Mh] Termos MeSH primário: Capnografia/métodos
Capnografia/normas
Espaço Morto Respiratório/fisiologia
[Mh] Termos MeSH secundário: Capnografia/tendências
Seres Humanos
Unidades de Terapia Intensiva/organização & administração
Embolia Pulmonar/diagnóstico
Respiração Artificial/métodos
Respiração Artificial/normas
Síndrome do Desconforto Respiratório do Adulto/diagnóstico
Síndrome do Desconforto Respiratório do Adulto/mortalidade
Síndrome do Desconforto Respiratório do Adulto/terapia
Terapia Trombolítica
Relação Ventilação-Perfusão/fisiologia
Desmame do Respirador/tendências
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T; REVIEW
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171031
[Lr] Data última revisão:
171031
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:160624
[St] Status:MEDLINE
[do] DOI:10.1186/s13054-016-1377-3


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[PMID]:27321293
[Au] Autor:Zhang YJ; Gao XJ; Li ZB; Wang ZY; Feng QS; Yin CF; Lu X; Xu L
[Ad] Endereço:Department of Critical Care Medicine, Third Central Clinical Departmrnt of Tianjin Medical University, Tianjin 300170, China.
[Ti] Título:Comparison of the pulmonary dead-space fraction derived from ventilator volumetric capnography and a validated equation in the survival prediction of patients with acute respiratory distress syndrome.
[So] Source:Chin J Traumatol;19(3):141-5, 2016 Jun 01.
[Is] ISSN:1008-1275
[Cp] País de publicação:China
[La] Idioma:eng
[Ab] Resumo:PURPOSE: This prospective observational study aims to evaluate the accuracy of dead-space fraction derived from the ventilator volumetric capnography (volumetric CO2) or a prediction equation to predict the survival of mechanically ventilated patients with acute respiratory distress syndrome (ARDS). METHODS: Consecutive VD/VT measurements were obtained based upon a prediction equation validated by Frankenfield et al for dead-space ventilation fraction: VD/VT = 0.320 + 0.0106 (PaCO2-ETCO2)⁺ 0.003 (RR)⁺0.0015 (age) in adult patients who had infection-related severe pneumonia and were confirmed as having ARDS. Here PaCO2 is the arterial partial pressure of carbon dioxide in mmHg; ETCO2, the end- tidal carbon dioxide measurement in mmHg; RR, respiratory rate per minute; and age in years. Once the patient had intubation, positive end expiratory pressure was adjusted and after Phigh reached a steady state, VD/VT was measured and recorded as the data for the first day. VD/VT measurement was repeated on days 2, 3, 4, 5 and 6. Meanwhile we collected dead-space fraction directly from the ventilator volu- metric CO2 and recorded it as Vd/Vt. We analyzed the changes in VD/VT and Vd/Vt over the 6-day period to determine their accuracy in predicting the survival of ARDS patients. RESULTS: Overall, 46 patients with ARDS met the inclusion criteria and 24 of them died. During the first 6 days of intubation, VD/VT was significantly higher in nonsurvivors on day 4 (0.70 ± 0.01 vs 0.57 ± 0.01), day 5 (0.73 ± 0.01 vs. 0.54 ± 0.01), and day 6 (0.73 ± 0.02 vs. 0.54 ± 0.01) (all p =0.000). Vd/Vt showed no significant difference on days 1e4 but it was much higher in nonsurvivors on day 5 (0.45 ± 0.04 vs. 0.41 ± 0.06) and day 6 (0.47 ± 0.05 vs. 0.40 ± 0.03) (both p=0.008). VD/VT on the fourth day was more accurate to predict survival than Vd/Vt. The area under the receiver-operating characteristic curve for VD/VT and Vd/Vt in evaluating ARDS patients survival was day 4 (0.974 ± 0.093 vs. 0.701 ± 0.023, p = 0.0024) with the 95% confidence interval being 0.857-0.999 vs. 0.525-0.841. CONCLUSION: Compared with Vd/Vt derived from ventilator volumetric CO2, VD/VT on day 4 calculated by Frankenfield et al's equation can more accurately predict the survival of ARDS patients.
[Mh] Termos MeSH primário: Capnografia
Respiração Artificial
Espaço Morto Respiratório/fisiologia
Síndrome do Desconforto Respiratório do Adulto/mortalidade
[Mh] Termos MeSH secundário: Adulto
Feminino
Seres Humanos
Masculino
Meia-Idade
Estudos Prospectivos
Curva ROC
Síndrome do Desconforto Respiratório do Adulto/fisiopatologia
[Pt] Tipo de publicação:COMPARATIVE STUDY; JOURNAL ARTICLE
[Em] Mês de entrada:1705
[Cu] Atualização por classe:170509
[Lr] Data última revisão:
170509
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:160621
[St] Status:MEDLINE


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[PMID]:27145818
[Au] Autor:Doorduin J; Nollet JL; Vugts MP; Roesthuis LH; Akankan F; van der Hoeven JG; van Hees HW; Heunks LM
[Ad] Endereço:Department of Critical Care Medicine, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525, GA, Nijmegen, The Netherlands.
[Ti] Título:Assessment of dead-space ventilation in patients with acute respiratory distress syndrome: a prospective observational study.
[So] Source:Crit Care;20(1):121, 2016 May 05.
[Is] ISSN:1466-609X
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:BACKGROUND: Physiological dead space (VD/VT) represents the fraction of ventilation not participating in gas exchange. In patients with acute respiratory distress syndrome (ARDS), VD/VT has prognostic value and can be used to guide ventilator settings. However, VD/VT is rarely calculated in clinical practice, because its measurement is perceived as challenging. Recently, a novel technique to calculate partial pressure of carbon dioxide in alveolar air (PACO2) using volumetric capnography (VCap) was validated. The purpose of the present study was to evaluate how VCap and other available techniques to measure PACO2 and partial pressure of carbon dioxide in mixed expired air (PeCO2) affect calculated VD/VT. METHODS: In a prospective, observational study, 15 post-cardiac surgery patients and 15 patients with ARDS were included. PACO2 was measured using VCap to calculate Bohr dead space or substituted with partial pressure of carbon dioxide in arterial blood (PaCO2) to calculate the Enghoff modification. PeCO2 was measured in expired air using three techniques: Douglas bag (DBag), indirect calorimetry (InCal), and VCap. Subsequently, VD/VT was calculated using four methods: Enghoff-DBag, Enghoff-InCal, Enghoff-VCap, and Bohr-VCap. RESULTS: PaCO2 was higher than PACO2, particularly in patients with ARDS (post-cardiac surgery PACO2 = 4.3 ± 0.6 kPa vs. PaCO2 = 5.2 ± 0.5 kPa, P < 0.05; ARDS PACO2 = 3.9 ± 0.8 kPa vs. PaCO2 = 6.9 ± 1.7 kPa, P < 0.05). There was good agreement in PeCO2 calculated with DBag vs. VCap (post-cardiac surgery bias = 0.04 ± 0.19 kPa; ARDS bias = 0.03 ± 0.27 kPa) and relatively low agreement with DBag vs. InCal (post-cardiac surgery bias = -1.17 ± 0.50 kPa; ARDS mean bias = -0.15 ± 0.53 kPa). These differences strongly affected calculated VD/VT. For example, in patients with ARDS, VD/VTcalculated with Enghoff-InCal was much higher than Bohr-VCap (VD/VT Enghoff-InCal = 66 ± 10 % vs. VD/VT Bohr-VCap = 45 ± 7 %; P < 0.05). CONCLUSIONS: Different techniques to measure PACO2 and PeCO2 result in clinically relevant mean and individual differences in calculated VD/VT, particularly in patients with ARDS. Volumetric capnography is a promising technique to calculate true Bohr dead space. Our results demonstrate the challenges clinicians face in interpreting an apparently simple measurement such as VD/VT.
[Mh] Termos MeSH primário: Espaço Morto Respiratório/fisiologia
Síndrome do Desconforto Respiratório do Adulto/fisiopatologia
[Mh] Termos MeSH secundário: Idoso
Idoso de 80 Anos ou mais
Capnografia/métodos
Feminino
Seres Humanos
Masculino
Meia-Idade
Monitorização Fisiológica/métodos
Estudos Prospectivos
Troca Gasosa Pulmonar/fisiologia
Síndrome do Desconforto Respiratório do Adulto/complicações
[Pt] Tipo de publicação:JOURNAL ARTICLE; OBSERVATIONAL STUDY
[Em] Mês de entrada:1701
[Cu] Atualização por classe:170117
[Lr] Data última revisão:
170117
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:160506
[St] Status:MEDLINE
[do] DOI:10.1186/s13054-016-1311-8


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[PMID]:26742626
[Au] Autor:Neumann RP; Pillow JJ; Thamrin C; Frey U; Schulzke SM
[Ad] Endereço:Department of Neonatology, University of Basel Children's Hospital, Basel, Switzerland. Electronic address: roland.neumann@ukbb.ch.
[Ti] Título:Influence of respiratory dead space on lung clearance index in preterm infants.
[So] Source:Respir Physiol Neurobiol;223:43-8, 2016 Mar.
[Is] ISSN:1878-1519
[Cp] País de publicação:Netherlands
[La] Idioma:eng
[Ab] Resumo:Lung clearance index (LCI), a marker of ventilation inhomogeneity derived from multiple breath washout (MBW), is used for clinical monitoring and as a key outcome of clinical trials in infants and children with cystic fibrosis. Utility of LCI is controversial in preterm infants with bronchopulmonary dysplasia (BPD) who tend to have high dead space to tidal volume ratio (VD/VT). We investigated the effect of VD/VT on LCI in a cohort of preterm infants with and without BPD and term healthy controls. We analyzed MBW data from 455 infants at a mean (SD) of 43.4 (3.5) w postmenstrual age. VD was estimated from the molar mass signal of an ultrasonic flowmeter (VD,MM). LCI was associated with VD,MM/VT (r(2)=0.13, p<0.001) but was not associated with BPD. Adjusting for VD,MM/VT did not reveal an association between LCI and BPD. We conclude that VD,MM/VT is a relevant factor when interpreting LCI in this population but the effect size of this association is moderate.
[Mh] Termos MeSH primário: Displasia Broncopulmonar/fisiopatologia
Espaço Morto Respiratório/fisiologia
Testes de Função Respiratória
[Mh] Termos MeSH secundário: Feminino
Idade Gestacional
Seres Humanos
Lactente
Recém-Nascido
Recém-Nascido Prematuro
Masculino
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T
[Em] Mês de entrada:1612
[Cu] Atualização por classe:161230
[Lr] Data última revisão:
161230
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:160109
[St] Status:MEDLINE


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[PMID]:26735905
[Au] Autor:Kee K; Stuart-Andrews C; Ellis MJ; Wrobel JP; Nilsen K; Sharma M; Thompson BR; Naughton MT
[Ad] Endereço:1 Department of Allergy, Immunology and Respiratory Medicine, The Alfred, Prahran, Victoria, Australia; and.
[Ti] Título:Increased Dead Space Ventilation Mediates Reduced Exercise Capacity in Systolic Heart Failure.
[So] Source:Am J Respir Crit Care Med;193(11):1292-300, 2016 Jun 01.
[Is] ISSN:1535-4970
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:RATIONALE: Patients with chronic heart failure have limited exercise capacity, which cannot be completely explained by markers of cardiac dysfunction. Reduced pulmonary diffusing capacity at rest and excessively high ventilation during exercise are common in heart failure. We hypothesized that the reduced pulmonary diffusing capacity in patients with heart failure would predict greater dead space ventilation during exercise and that this would lead to impairment in exercise capacity. OBJECTIVES: To determine the relationship between pulmonary diffusing capacity at rest and dead space ventilation during exercise, and to examine the influence of dead space ventilation on exercise in heart failure. METHODS: We analyzed detailed cardiac and pulmonary data at rest and during maximal incremental cardiopulmonary exercise testing from 87 consecutive heart transplant assessment patients and 18 healthy control subjects. Dead space ventilation was calculated using the Bohr equation. MEASUREMENTS AND MAIN RESULTS: Pulmonary diffusing capacity at rest was a significant predictor of dead space ventilation at maximal exercise (r = -0.524, P < 0.001) in heart failure but not in control subjects. Dead space at maximal exercise also correlated inversely with peak oxygen consumption (r = -0.598, P < 0.001), peak oxygen consumption per kilogram (r = -0.474, P < 0.001), and 6-minute-walk distance (r = -0.317, P = 0.021) in the heart failure group but not in control subjects. CONCLUSIONS: Low resting pulmonary diffusing capacity in heart failure is indicative of high dead space ventilation during exercise, leading to excessive and inefficient ventilation. These findings would support the concept of pulmonary vasculopathy leading to altered ventilation perfusion matching (increased dead space) and resultant dyspnea, independent of markers of cardiac function.
[Mh] Termos MeSH primário: Teste de Esforço/estatística & dados numéricos
Tolerância ao Exercício/fisiologia
Insuficiência Cardíaca Sistólica/fisiopatologia
Consumo de Oxigênio/fisiologia
Espaço Morto Respiratório/fisiologia
[Mh] Termos MeSH secundário: Adulto
Feminino
Seres Humanos
Masculino
Meia-Idade
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Em] Mês de entrada:1706
[Cu] Atualização por classe:170621
[Lr] Data última revisão:
170621
[Sb] Subgrupo de revista:AIM; IM
[Da] Data de entrada para processamento:160107
[St] Status:MEDLINE
[do] DOI:10.1164/rccm.201508-1555OC



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