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Jayasimhan D, Chieng J, Kolbe J, Sidebotham DA. Dead-Space Ventilation Indices and Mortality in Acute Respiratory Distress Syndrome: A Systematic Review and Meta-Analysis. Crit Care Med 2023; 51:1363-1372. [PMID: 37204257 DOI: 10.1097/ccm.0000000000005921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
OBJECTIVES Acute respiratory distress syndrome (ARDS) is associated with high ventilation-perfusion heterogeneity and dead-space ventilation. However, whether the degree of dead-space ventilation is associated with outcomes is uncertain. In this systematic review and meta-analysis, we evaluated the ability of dead-space ventilation measures to predict mortality in patients with ARDS. DATA SOURCES MEDLINE, CENTRAL, and Google Scholar from inception to November 2022. STUDY SELECTION Studies including adults with ARDS reporting a dead-space ventilation index and mortality. DATA EXTRACTION Two reviewers independently identified eligible studies and extracted data. We calculated pooled effect estimates using a random effects model for both adjusted and unadjusted results. The quality and strength of evidence were assessed using the Quality in Prognostic Studies and Grading of Recommendations, Assessment, Development, and Evaluation, respectively. DATA SYNTHESIS We included 28 studies in our review, 21 of which were included in our meta-analysis. All studies had a low risk of bias. A high pulmonary dead-space fraction was associated with increased mortality (odds ratio [OR], 3.52; 95% CI, 2.22-5.58; p < 0.001; I2 = 84%). After adjusting for other confounding variables, every 0.05 increase in pulmonary-dead space fraction was associated with an increased odds of death (OR, 1.23; 95% CI, 1.13-1.34; p < 0.001; I2 = 57%). A high ventilatory ratio was also associated with increased mortality (OR, 1.55; 95% CI, 1.33-1.80; p < 0.001; I2 = 48%). This association was independent of common confounding variables (OR, 1.33; 95% CI, 1.12-1.58; p = 0.001; I2 = 66%). CONCLUSIONS Dead-space ventilation indices were independently associated with mortality in adults with ARDS. These indices could be incorporated into clinical trials and used to identify patients who could benefit from early institution of adjunctive therapies. The cut-offs identified in this study should be prospectively validated.
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Affiliation(s)
- Dilip Jayasimhan
- Cardiothoracic and Vascular Intensive Care Unit, Te Whatu Ora Te Toka Tumai Auckland, Auckland, New Zealand
- Respiratory Services, Te Whatu Ora Te Toka Tumai Auckland, Auckland, New Zealand
| | - Jennifer Chieng
- Respiratory Services, Te Whatu Ora Te Toka Tumai Auckland, Auckland, New Zealand
| | - John Kolbe
- Respiratory Services, Te Whatu Ora Te Toka Tumai Auckland, Auckland, New Zealand
- Department of Medicine, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - David A Sidebotham
- Cardiothoracic and Vascular Intensive Care Unit, Te Whatu Ora Te Toka Tumai Auckland, Auckland, New Zealand
- Department of Medicine, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
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Yang Y, Chi Y, Yuan S, Zhang Q, Su L, Long Y, He H. The relationship between ventilatory ratio (VR) and 28-day hospital mortality by restricted cubic splines (RCS) in 14,328 mechanically ventilated ICU patients. BMC Pulm Med 2022; 22:229. [PMID: 35698114 PMCID: PMC9191763 DOI: 10.1186/s12890-022-02019-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2022] [Accepted: 05/31/2022] [Indexed: 11/28/2022] Open
Abstract
Background Previous studies found that high levels of ventilatory ratio (VR) were associated with a poor prognosis due to worse ventilatory efficiency in acute respiratory distress syndrome patients. However, relatively few large studies have assessed the association between VR and intensive care unit (ICU) mortality in the general adult ventilated population. Methods The present study is a retrospective cohort study. Patients mechanically ventilated for more than 12 h were included. VR was calculated based on a previously reported formula. Restricted cubic spline models were used to fit the relationship between VR and mortality risks. Results A total of 14,328 mechanically ventilated ICU patients were included in the study, of which 1311 died within 28 days. The results of the study are as follows: (1) In the general adult ventilated population, VR was positively associated with 28-day mortality when VR ≥ 1.3 (increase of 0.1 per VR; HR 1.05, p < 0.001). The same tendency was also observed in the populations of severe hypoxemia with a PaO2/FiO2 (P/F) ratio < 200 mmHg. (2) However, in the population with a P/F ratio ≥ 200, a J-shaped dose–response association between VR and the risk of mortality was observed, with the risk of death positively associated with VR when VR ≥ 0.9 (10% increase in HR for every 0.1 increase in VR, p = 0.000) but negatively associated with VR when VR < 0.9 (10% decrease in HR for every 0.1 increase in VR, p = 0.034). In the population of P/F ratio ≥ 200 with VR less than 0.9, compared to the survival group, the nonsurvival group had a lower level PCO2 (33 mmHg [29.1, 37.9] vs. 34.4 mmHg [30.6, 38.5]), rather than a significant level of measured minute ventilation or P/F ratio. Conclusions VR was positively associated with the risk of death in the general ICU population; however, VR was inversely associated with 28-day mortality in the population with a P/F ratio ≥ 200 and low VR . Further research should investigate this relationship, and VR should be interpreted with caution in clinical practice.
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Affiliation(s)
- Yingying Yang
- Department of Critical Care Medicine, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Science, Beijing, 100730, China
| | - Yi Chi
- Department of Critical Care Medicine, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Science, Beijing, 100730, China
| | - Siyi Yuan
- Department of Critical Care Medicine, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Science, Beijing, 100730, China
| | - Qing Zhang
- Department of Critical Care Medicine, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Science, Beijing, 100730, China
| | - Longxiang Su
- Department of Critical Care Medicine, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Science, Beijing, 100730, China
| | - Yun Long
- Department of Critical Care Medicine, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Science, Beijing, 100730, China.
| | - Huaiwu He
- Department of Critical Care Medicine, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Science, Beijing, 100730, China.
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Jiang H, Wu X, Lian S, Zhang C, Liu S, Jiang Z. Effects of salbutamol on the kinetics of sevoflurane and the occurrence of early postoperative pulmonary complications in patients with mild-to-moderate chronic obstructive pulmonary disease: A randomized controlled study. PLoS One 2021; 16:e0251795. [PMID: 34015036 PMCID: PMC8136676 DOI: 10.1371/journal.pone.0251795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2020] [Accepted: 05/01/2021] [Indexed: 11/23/2022] Open
Abstract
Bronchodilators dilate the bronchi and increase lung volumes, thereby improving respiratory physiology in patients with chronic obstructive pulmonary disease (COPD). However, their effects on sevoflurane kinetics remain unknown. We aimed to determine whether inhaled salbutamol affected the wash-in and wash-out kinetics of sevoflurane and the occurrence of early postoperative pulmonary complications (PPCs) in patients with COPD undergoing elective surgery. This randomized, placebo-controlled study included 63 consecutive patients with COPD allocated to the salbutamol (n = 30) and control groups (n = 33). The salbutamol group received salbutamol aerosol (2 puffs of ~200 μg) 30 min before anesthesia induction and 30 min before surgery completion. The control group received a placebo. Sevoflurane kinetics were determined by collecting end-tidal samples from the first breaths at 1, 2, 3, 4, 5, 7, 10, and 15 min before the surgery (wash-in) and after closing the vaporizer (wash-out). PPCs were recorded for 7 days. The salbutamol group had higher end-tidal to inhaled sevoflurane ratios (p<0.05, p<0.01) than the control group, from 3 to 10 min during the wash-in period, but no significant differences were observed during the wash-out period. The arterial partial pressure of oxygen to the fraction of inhaled oxygen was significantly higher in the salbutamol group at 30 (320.3±17.6 vs. 291.5±29.6 mmHg; p = 0.033) and 60 min (327.8±32.3 vs. 309.2±30.5 mmHg; p = 0.003). The dead space to tidal volume ratios at 30 (20.5±6.4% vs. 26.3±6.0%, p = 0.042) and 60 min (19.6±5.1% vs. 24.8±5.5%, p = 0.007) and the incidence of bronchospasm (odds ratio [OR] 0.45, 95% confidence interval [CI] 0.23–0.67, p = 0.023) and respiratory infiltration (OR 0.52, 95% CI, 0.40–0.65, p = 0.017) were lower in the salbutamol group. In patients with COPD, salbutamol accelerates the wash-in rate of sevoflurane and decreases the occurrence of postoperative bronchospasm and pulmonary infiltration within the first 7 days.
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Affiliation(s)
- Huayong Jiang
- Department of Anesthesia, Shaoxing People’s Hospital (Shaoxing Hospital, Zhejiang University of School of Medicine), Shaoxing, Zhejiang Province, PR China
| | - Xiujuan Wu
- Department of Nephrology, Shaoxing People’s Hospital (Shaoxing Hospital, Zhejiang University of School of Medicine), Shaoxing, Zhejiang Province, PR China
| | - Shumei Lian
- Department of Anesthesia, Shaoxing People’s Hospital (Shaoxing Hospital, Zhejiang University of School of Medicine), Shaoxing, Zhejiang Province, PR China
| | - Changfeng Zhang
- Department of Anesthesia, Shaoxing People’s Hospital (Shaoxing Hospital, Zhejiang University of School of Medicine), Shaoxing, Zhejiang Province, PR China
| | - Shuyun Liu
- Department of Anesthesia, Shaoxing People’s Hospital (Shaoxing Hospital, Zhejiang University of School of Medicine), Shaoxing, Zhejiang Province, PR China
| | - Zongming Jiang
- Department of Anesthesia, Shaoxing People’s Hospital (Shaoxing Hospital, Zhejiang University of School of Medicine), Shaoxing, Zhejiang Province, PR China
- * E-mail:
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Chuang ML, Hsieh BYT, Lin IF. Resting Dead Space Fraction as Related to Clinical Characteristics, Lung Function, and Gas Exchange in Male Patients with Chronic Obstructive Pulmonary Disease. Int J Gen Med 2021; 14:169-177. [PMID: 33568934 PMCID: PMC7868954 DOI: 10.2147/ijgm.s291555] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Accepted: 12/30/2020] [Indexed: 12/16/2022] Open
Abstract
Background Measures of forced expired volume in one second % predicted (FEV1%), residual volume to total lung capacity ratio (RV/TLC) and diffusing capacity for carbon monoxide measurements (DLCO) are the standard lung function test for evaluating patients with chronic obstructive pulmonary disease (COPD). The dead space fraction (VD/VT) has been shown to be a robust marker of gas exchange abnormality. However, the use of VD/VT has gradually become less common. As VD/VT measured at rest (VD/VTR) has been successfully used in non-COPD conditions, it was hypothesized that in COPD the VD/VTR was more sensitive than the standard lung function test in correlation with clinical characteristics and gas exchange. This study aimed to test the hypothesis and to identify the variables relevant to VD/VTR. Methods A total of 46 male subjects with COPD were enrolled. Clinical characteristics included demographic data, oxygen-cost diagram (OCD), and image studies for pulmonary hypertension. The standard lung function was obtained. To calculate VD/VT, invasive arterial blood gas and pulmonary gas exchange (PGX) were measured. The variables relevant to VD/VTR were analyzed by multiple linear regression. Results Compared to lung function, VD/VTR was more frequently and significantly related to smoking, carboxyhemoglobin level, pulmonary hypertension and PaCO2 (all p <0.05) whereas FEV1% was more related to lung function test, PaO2 and OCD score. VD/VTR and FEV1% were highly related to resting gas exchange but RV/TLC and DLCO% were not. Cigarette consumption, the equivalent for CO2 output, arterial oxyhemoglobin saturation, and the product of tidal volume and inspiratory duty cycle were identified as the parameters relevant to VD/VTR with a power of 0.72. Conclusion Compared to lung function test, VD/VTR is more related to clinical characteristics and is a comprehensive marker of resting gas exchange. Further studies are warranted to provide a noninvasive measurement of VD/VTR. Registration Number MOST 106-2314-B-040-025 and CSH-2019-C-30.
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Affiliation(s)
- Ming-Lung Chuang
- Division of Pulmonary Medicine and Department of Internal Medicine, Chung Shan Medical University Hospital, Taichung, Taiwan, 40201, Republic of China.,School of Medicine, Chung Shan Medical University, Taichung, Taiwan, 40201, Republic of China
| | | | - I-Feng Lin
- Institute of Public Health, National Yang Ming University, Taipei, Taiwan, 11221, Republic of China
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Varón-Vega F, Hernández Á, López M, Cáceres E, Giraldo-Cadavid LF, Uribe-Hernandez AM, Crevoisier S. [Usefulness of diaphragmatic ultrasound in predicting extubation success]. Med Intensiva 2019; 45:226-233. [PMID: 31870509 DOI: 10.1016/j.medin.2019.10.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 09/16/2019] [Accepted: 10/24/2019] [Indexed: 10/25/2022]
Abstract
OBJECTIVE To evaluate the diagnostic accuracy of diaphragmatic ultrasound in predicting extubation success. DESIGN A diagnostic accuracy study was carried out. SCOPE Intensive Care Unit of an Academic hospital in the city of Bogotá (Colombia). PATIENTS OR PARTICIPANTS A consecutive sample of patients >18 years of age subjected to invasive mechanical ventilation for >48h. INTERVENTIONS Diaphragmatic ultrasound evaluation at the end of spontaneous ventilation testing. MAIN VARIABLES OF INTEREST Diaphragmatic excursion (DE, cm), inspiration time (TPIAdia, s), diaphragm contraction speed (DE/TPIAdia, cm/s) and total time (Ttot, s) were evaluated, together with thickening fraction (TFdi, %). RESULTS A total of 84 patients were included, 79.8% (n=67) with successful extubation and 20.2% (n=17) with failed extubation. The variable with the best discriminatory capacity in predicting extubation success was diaphragm contraction speed, with AUC-ROC 0.70 (p=0.008). CONCLUSIONS Diaphragm contraction speed exhibited acceptable discriminatory capacity. Ultrasound could be part of a multifactorial approach in the extubation process.
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Affiliation(s)
- F Varón-Vega
- Unidad de Cuidado Intensivo Médico, Fundación Neumológica Colombiana, Bogotá, Colombia; Fundación Cardioinfantil-Instituto de Cardiología, Bogotá, Colombia; Departamento de Anestesiología y Cuidados Intensivos, Universidad de Navarra, Pamplona, España
| | - Á Hernández
- Unidad de Cuidado Intensivo Médico, Fundación Neumológica Colombiana, Bogotá, Colombia
| | - M López
- Unidad de Cuidado Intensivo Médico, Fundación Neumológica Colombiana, Bogotá, Colombia
| | - E Cáceres
- Unidad de Cuidado Intensivo Médico, Fundación Neumológica Colombiana, Bogotá, Colombia
| | - L F Giraldo-Cadavid
- Departamento de Investigación, Fundación Neumológica Colombiana, Bogotá, Colombia; Departamento de Epidemiología y de Medicina Interna, Universidad de La Sabana, Chía, Colombia
| | - A M Uribe-Hernandez
- Unidad de Cuidado Intensivo Médico, Fundación Neumológica Colombiana, Bogotá, Colombia; Fundación Cardioinfantil-Instituto de Cardiología, Bogotá, Colombia; Departamento de Investigación, Fundación Neumológica Colombiana, Bogotá, Colombia.
| | - S Crevoisier
- Medicina Crítica y Cuidado Intensivo, Universidad de La Sabana, Chía, Colombia
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Sinha P, Calfee CS, Beitler JR, Soni N, Ho K, Matthay MA, Kallet RH. Physiologic Analysis and Clinical Performance of the Ventilatory Ratio in Acute Respiratory Distress Syndrome. Am J Respir Crit Care Med 2019; 199:333-341. [PMID: 30211618 DOI: 10.1164/rccm.201804-0692oc] [Citation(s) in RCA: 182] [Impact Index Per Article: 36.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
RATIONALE Pulmonary dead space fraction (Vd/Vt) is an independent predictor of mortality in acute respiratory distress syndrome (ARDS). Yet, it is seldom used in practice. The ventilatory ratio is a simple bedside index that can be calculated using routinely measured respiratory variables and is a measure of impaired ventilation. Ventilatory ratio is defined as [minute ventilation (ml/min) × PaCO2 (mm Hg)]/(predicted body weight × 100 × 37.5). OBJECTIVES To determine the relation of ventilatory ratio with Vd/Vt in ARDS. METHODS First, in a single-center, prospective observational study of ARDS, we tested the association of Vd/Vt with ventilatory ratio. With in-hospital mortality as the primary outcome and ventilator-free days as the secondary outcome, we tested the role of ventilatory ratio as an outcome predictor. The findings from this study were further verified in secondary analyses of two NHLBI ARDS Network randomized controlled trials. MEASUREMENTS AND MAIN RESULTS Ventilatory ratio positively correlated with Vd/Vt. Ordinal groups of ventilatory ratio had significantly higher Vd/Vt. Ventilatory ratio was independently associated with increased risk of mortality after adjusting for PaO2/FiO2, and positive end-expiratory pressure (odds ratio, 1.51; P = 0.024) and after adjusting for Acute Physiologic Assessment and Chronic Health Evaluation II score (odds ratio, 1.59; P = 0.04). These findings were further replicated in secondary analyses of two separate NHLBI randomized controlled trials. CONCLUSIONS Ventilatory ratio correlates well with Vd/Vt in ARDS, and higher values at baseline are associated with increased risk of adverse outcomes. These results are promising for the use of ventilatory ratio as a simple bedside index of impaired ventilation in ARDS.
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Affiliation(s)
- Pratik Sinha
- 1 Division of Pulmonary, Critical Care, Allergy and Sleep Medicine, Department of Medicine
| | - Carolyn S Calfee
- 1 Division of Pulmonary, Critical Care, Allergy and Sleep Medicine, Department of Medicine.,2 Department of Anesthesia, and.,3 Cardiovascular Research Institute, University of California, San Francisco, San Francisco, California
| | - Jeremy R Beitler
- 4 Division of Pulmonary and Critical Care Medicine, University of California, San Diego, San Diego, California
| | - Neil Soni
- 5 Magill Department of Anaesthesia, Intensive Care Medicine and Pain Management, Chelsea and Westminster Hospital, London, United Kingdom; and
| | - Kelly Ho
- 6 Respiratory Care Services, Department of Anesthesia and Perioperative Care, University of California, San Francisco at Zuckerberg San Francisco General Hospital and Trauma Center, San Francisco, California
| | - Michael A Matthay
- 1 Division of Pulmonary, Critical Care, Allergy and Sleep Medicine, Department of Medicine.,2 Department of Anesthesia, and.,3 Cardiovascular Research Institute, University of California, San Francisco, San Francisco, California
| | - Richard H Kallet
- 6 Respiratory Care Services, Department of Anesthesia and Perioperative Care, University of California, San Francisco at Zuckerberg San Francisco General Hospital and Trauma Center, San Francisco, California
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7
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Sun Q, Liu L, Pan C, Zhao Z, Xu J, Liu A, Qiu H. Effects of neurally adjusted ventilatory assist on air distribution and dead space in patients with acute exacerbation of chronic obstructive pulmonary disease. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2017; 21:126. [PMID: 28578708 PMCID: PMC5455203 DOI: 10.1186/s13054-017-1714-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Accepted: 05/09/2017] [Indexed: 11/16/2022]
Abstract
Background Neurally adjusted ventilatory assist (NAVA) could improve patient-ventilator interaction; its effects on ventilation distribution and dead space are still unknown. The aim of this study was to evaluate the effects of varying levels of assist during NAVA and pressure support ventilation (PSV) on ventilation distribution and dead space in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD). Methods Fifteen mechanically ventilated patients with AECOPD were included in the study. The initial PSV levels were set to 10 cmH2O for 10 min. Thereafter, the ventilator mode was changed to NAVA for another 10 min with the same electrical activity of the diaphragm as during PSV. Furthermore, the ventilation mode was switched between PSV and NAVA every 10 min in the following order: PSV 5 cmH2O; NAVA 50%; PSV 15 cmH2O; and NAVA 150% (relative to the initial NAVA support level). Ventilation distribution in the lung was evaluated in percentages in regions of interest (ROI) of four anteroposterior segments of equal height (ROI1 to ROI4 represents ventral, mid-ventral, mid-dorsal, and dorsal, respectively). Blood gases, ventilation distribution (electrical impedance tomography), diaphragm activity (B-mode ultrasonography), and dead space fraction (PeCO2 and PaCO2) were measured. Results The trigger and cycle delays were lower during NAVA than during PSV. The work of trigger was significantly lower during NAVA compared to PSV. The diaphragm activities based on ultrasonography were higher during NAVA compared to the same support level during PSV. The ventilation distribution in ROI4 increased significantly (P < 0.05) during NAVA compared to PSV (except for a support level of 50%). Similar results were found in ROI3 + 4. NAVA reduced dead space fraction compared to the corresponding support level of PSV. Conclusions NAVA was superior to PSV in AECOPD for increasing ventilation distribution in ROI4 and reducing dead space. Trial registration Clinicaltrials.gov, NCT02289573. Registered on 12 November 2014.
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Affiliation(s)
- Qin Sun
- Department of Critical Care Medicine, Zhongda Hospital, School of Medicine, Southeast University, No.87, Dingjiaqiao Road, Gulou District, Nanjing, 210009, Jiangsu, China
| | - Ling Liu
- Department of Critical Care Medicine, Zhongda Hospital, School of Medicine, Southeast University, No.87, Dingjiaqiao Road, Gulou District, Nanjing, 210009, Jiangsu, China
| | - Chun Pan
- Department of Critical Care Medicine, Zhongda Hospital, School of Medicine, Southeast University, No.87, Dingjiaqiao Road, Gulou District, Nanjing, 210009, Jiangsu, China
| | - Zhanqi Zhao
- Institute of Technical Medicine, Furtwangen University, Villingen-Schwenningen, Germany
| | - Jingyuan Xu
- Department of Critical Care Medicine, Zhongda Hospital, School of Medicine, Southeast University, No.87, Dingjiaqiao Road, Gulou District, Nanjing, 210009, Jiangsu, China
| | - Airan Liu
- Department of Critical Care Medicine, Zhongda Hospital, School of Medicine, Southeast University, No.87, Dingjiaqiao Road, Gulou District, Nanjing, 210009, Jiangsu, China
| | - Haibo Qiu
- Department of Critical Care Medicine, Zhongda Hospital, School of Medicine, Southeast University, No.87, Dingjiaqiao Road, Gulou District, Nanjing, 210009, Jiangsu, China.
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Can Transcutaneous CO2 Tension Be Used to Calculate Ventilatory Dead Space? A Pilot Study. Crit Care Res Pract 2016; 2016:9874150. [PMID: 27688911 PMCID: PMC5027368 DOI: 10.1155/2016/9874150] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2016] [Revised: 08/07/2016] [Accepted: 08/16/2016] [Indexed: 11/18/2022] Open
Abstract
Dead space fraction (Vd/Vt) measurement performed using volumetric capnography requires arterial blood gas (ABG) sampling to estimate the partial pressure of carbon dioxide (PaCO2). In recent years, transcutaneous capnography (PtcCO2) has emerged as a noninvasive method of estimating PaCO2. We hypothesized that PtcCO2 can be used as a substitute for PaCO2 in the calculation of Vd/Vt. In this prospective pilot comparison study, 30 consecutive postcardiac surgery mechanically ventilated patients had Vd/Vt calculated separately using volumetric capnography by substituting PtcCO2 for PaCO2. The mean Vd/Vt calculated using PaCO2 and PtcCO2 was 0.48 ± 0.09 and 0.53 ± 0.08, respectively, with a strong positive correlation between the two methods of calculation (Pearson's correlation = 0.87, p < 0.05). Bland-Altman analysis showed a mean difference of −0.05 (95% CI: −0.01 to −0.09) between the two methods. PtcCO2 measurements can provide a noninvasive means to measure Vd/Vt, thus accessing important physiologic information and prognostic assessment in patients receiving mechanical ventilation.
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Verscheure S, Massion PB, Verschuren F, Damas P, Magder S. Volumetric capnography: lessons from the past and current clinical applications. Crit Care 2016; 20:184. [PMID: 27334879 PMCID: PMC4918076 DOI: 10.1186/s13054-016-1377-3] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
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.
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Affiliation(s)
- Sara Verscheure
- Department of Critical Care Medicine, University of McGill, Montreal, Quebec, Canada.,Department of General Intensive Care, University Hospital of Liege, Liege, Belgium
| | - Paul B Massion
- Department of General Intensive Care, University Hospital of Liege, Liege, Belgium
| | - Franck Verschuren
- Department of Emergency Medicine, Cliniques universitaire Saint-Luc, Université Catholique de Louvain, Brussels, Belgium
| | - Pierre Damas
- Department of General Intensive Care, University Hospital of Liege, Liege, Belgium
| | - Sheldon Magder
- Department of Critical Care Medicine, University of McGill, Montreal, Quebec, Canada.
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Jaffe MB. Using the features of the time and volumetric capnogram for classification and prediction. J Clin Monit Comput 2016; 31:19-41. [PMID: 26780902 DOI: 10.1007/s10877-016-9830-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 01/06/2016] [Indexed: 12/18/2022]
Abstract
Quantitative features derived from the time-based and volumetric capnogram such as respiratory rate, end-tidal PCO2, dead space, carbon dioxide production, and qualitative features such as the shape of capnogram are clinical metrics recognized as important for assessing respiratory function. Researchers are increasingly exploring these and other known physiologically relevant quantitative features, as well as new features derived from the time and volumetric capnogram or transformations of these waveforms, for: (a) real-time waveform classification/anomaly detection, (b) classification of a candidate capnogram into one of several disease classes, (c) estimation of the value of an inaccessible or invasively determined physiologic parameter, (d) prediction of the presence or absence of disease condition, (e) guiding the administration of therapy, and (f) prediction of the likely future morbidity or mortality of a patient with a presenting condition. The work to date with respect to these applications will be reviewed, the underlying algorithms and performance highlighted, and opportunities for the future noted.
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Affiliation(s)
- Michael B Jaffe
- Cardiorespiratory Consulting, LLC, 410 Mountain Road, Cheshire, CT, 06410, USA.
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11
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Agmy GR, Mohammad HA, Hassanin AAM. The prognostic value of the dead-space fraction and other physiological parameters in the weaning process of mechanical ventilation in patients with obstructive air flow. THE EGYPTIAN JOURNAL OF BRONCHOLOGY 2015. [DOI: 10.4103/1687-8426.165902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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12
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Rasera CC, Gewehr PM, Domingues AMT. PETCO2measurement and feature extraction of capnogram signals for extubation outcomes from mechanical ventilation. Physiol Meas 2015; 36:231-42. [DOI: 10.1088/0967-3334/36/2/231] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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13
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Saeed AM, Asaal GME, Halim HAAE, Ahmad SA. Evaluation of the cardiopulmonary status using a noninvasive respiratory profile monitor in chronic obstructive lung disease patients during low-ventilation strategy. THE EGYPTIAN JOURNAL OF BRONCHOLOGY 2014. [DOI: 10.4103/1687-8426.137351] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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14
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Lin HT, Ting PC, Chang WY, Yang MW, Chang CJ, Chou AH. Predictive risk index and prognosis of postoperative reintubation after planned extubation during general anesthesia: A single-center retrospective case-controlled study in Taiwan from 2005 to 2009. ACTA ACUST UNITED AC 2013; 51:3-9. [DOI: 10.1016/j.aat.2013.03.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2012] [Revised: 10/25/2012] [Accepted: 10/30/2012] [Indexed: 01/17/2023]
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