scholarly journals Assessment of gradient between partial pressure of arterial carbon dioxide and end-tidal carbon dioxide in acute respiratory distress syndrome

2019 ◽  
Vol 13 (2) ◽  
pp. 170
Author(s):  
FatmaalzahraaS Abdalrazik ◽  
MohamedO Elghonemi
Keyword(s):  
Carbon Dioxide ◽  
Acute Respiratory Distress Syndrome ◽  
Respiratory Distress Syndrome ◽  
Respiratory Distress ◽  
Partial Pressure ◽  
Distress Syndrome ◽  
Arterial Carbon Dioxide ◽  
End Tidal Carbon Dioxide ◽  
End Tidal

Establishing a gradient between partial pressure of arterial carbon dioxide and end-tidal carbon dioxide in patients with acute respiratory distress syndrome

2016 ◽  
Vol 65 (2) ◽  
pp. 338-341 ◽  
Author(s):  
Tariq Yousuf ◽  
Taylor Brinton ◽  
Ghulam Murtaza ◽  
Daniel Wozniczka ◽  
Khansa Ahmad ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Acute Respiratory Distress Syndrome ◽  
Respiratory Distress Syndrome ◽  
Respiratory Distress ◽  
Distress Syndrome ◽  
Statistical Significance ◽  
End Tidal Carbon Dioxide ◽  
The Mean ◽  
The Difference ◽  
End Tidal

End-tidal carbon dioxide (ETCO2) monitoring is useful in many situations. However, ETCO2 monitoring is unreliable in patients with acute respiratory distress syndrome (ARDS) due to widespread lung inflammation. In our study, we attempt to establish the gradient between the arterial pressure of carbon dioxide (PaCO2) and ETCO2 in patients with ARDS, which we defined as the PaETCO2 gradient. The main objective of the study was to establish a PaETCO2 gradient in each severity of ARDS. We analyzed 35 patients with ARDS and a total of 88 arterial blood gases were included. PaCO2, PaO2/FiO2 and ETCO2 were measured. Patients were stratified into mild, moderate and severe ARDS as classified by the Berlin ARDS criteria. PaCO2 and ETCO2 were compared at each severity stratification. The mean PaCO2 was 50.0, the mean ETCO2 was 26.6 and the gradient among all samples was 23.24 (±12.02). The mean gradient for each severity is as follows: mild: 19.3 (±9.9), moderate: 27.9 (±13.2) and severe: 23.9 (±7.8). The difference between the PaETCO2 gradient of the mild to moderate (p=0.001) and mild to severe groups (p=0.01) reached statistical significance. However, the difference between the moderate to severe groups did not reach statistical significance (p=0.48). We found the gradient between PaCO2 and ETCO2 in patients with ARDS is vast and tends to worsen with increasing severity of ARDS. This indicates that the gradient between the 2 may be used as an indicator of increasing severity of ARDS.

scholarly journals Early effects of ventilatory rescue therapies on systemic and cerebral oxygenation in mechanically ventilated COVID-19 patients with acute respiratory distress syndrome: a prospective observational study

Critical Care ◽  
2021 ◽  
Vol 25 (1) ◽  
Author(s):  
Chiara Robba ◽  
◽  
Lorenzo Ball ◽  
Denise Battaglini ◽  
Danilo Cardim ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Acute Respiratory Distress Syndrome ◽  
Observational Study ◽  
Respiratory Distress Syndrome ◽  
Respiratory Distress ◽  
Prospective Observational Study ◽  
Distress Syndrome ◽  
Cerebral Oxygenation ◽  
Arterial Blood ◽  
Early Effects

Abstract Background In COVID-19 patients with acute respiratory distress syndrome (ARDS), the effectiveness of ventilatory rescue strategies remains uncertain, with controversial efficacy on systemic oxygenation and no data available regarding cerebral oxygenation and hemodynamics. Methods This is a prospective observational study conducted at San Martino Policlinico Hospital, Genoa, Italy. We included adult COVID-19 patients who underwent at least one of the following rescue therapies: recruitment maneuvers (RMs), prone positioning (PP), inhaled nitric oxide (iNO), and extracorporeal carbon dioxide (CO2) removal (ECCO2R). Arterial blood gas values (oxygen saturation [SpO2], partial pressure of oxygen [PaO2] and of carbon dioxide [PaCO2]) and cerebral oxygenation (rSO2) were analyzed before (T0) and after (T1) the use of any of the aforementioned rescue therapies. The primary aim was to assess the early effects of different ventilatory rescue therapies on systemic and cerebral oxygenation. The secondary aim was to evaluate the correlation between systemic and cerebral oxygenation in COVID-19 patients. Results Forty-five rescue therapies were performed in 22 patients. The median [interquartile range] age of the population was 62 [57–69] years, and 18/22 [82%] were male. After RMs, no significant changes were observed in systemic PaO2 and PaCO2 values, but cerebral oxygenation decreased significantly (52 [51–54]% vs. 49 [47–50]%, p < 0.001). After PP, a significant increase was observed in PaO2 (from 62 [56–71] to 82 [76–87] mmHg, p = 0.005) and rSO2 (from 53 [52–54]% to 60 [59–64]%, p = 0.005). The use of iNO increased PaO2 (from 65 [67–73] to 72 [67–73] mmHg, p = 0.015) and rSO2 (from 53 [51–56]% to 57 [55–59]%, p = 0.007). The use of ECCO2R decreased PaO2 (from 75 [75–79] to 64 [60–70] mmHg, p = 0.009), with reduction of rSO2 values (59 [56–65]% vs. 56 [53–62]%, p = 0.002). In the whole population, a significant relationship was found between SpO2 and rSO2 (R = 0.62, p < 0.001) and between PaO2 and rSO2 (R0 0.54, p < 0.001). Conclusions Rescue therapies exert specific pathophysiological mechanisms, resulting in different effects on systemic and cerebral oxygenation in critically ill COVID-19 patients with ARDS. Cerebral and systemic oxygenation are correlated. The choice of rescue strategy to be adopted should take into account both lung and brain needs. Registration The study protocol was approved by the ethics review board (Comitato Etico Regione Liguria, protocol n. CER Liguria: 23/2020).

Permissive Hypercapnia with and without Expiratory Washout in Patients with Severe Acute Respiratory Distress Syndrome 

1997 ◽  
Vol 87 (1) ◽  
pp. 6-17 ◽  
Author(s):  
Pierre Kalfon ◽  
G. S. Umamaheswara Rao ◽  
Lluis Gallart ◽  
Louis Puybasset ◽  
Pierre Coriat ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Acute Respiratory Distress Syndrome ◽  
Respiratory Distress Syndrome ◽  
Respiratory Distress ◽  
Injury Severity ◽  
Distress Syndrome ◽  
Permissive Hypercapnia ◽  
Positive End Expiratory Pressure ◽  
Ventilatory Strategy ◽  
Volume Curve

Background Permissive hypercapnia is a ventilatory strategy aimed at avoiding lung volutrauma in patients with severe acute respiratory distress syndrome (ARDS). Expiratory washout (EWO) is a modality of tracheal gas insufflation that enhances carbon dioxide removal during mechanical ventilation by reducing dead space. The goal of this prospective study was to determine the efficacy of EWO in reducing the partial pressure of carbon dioxide (PaCO2) in patients with severe ARDS treated using permissive hypercapnia. Methods Seven critically ill patients with severe ARDS (lung injury severity score, 3.1 +/- 0.3) and no contraindications for permissive hypercapnia were studied. On the first day, hemodynamic and respiratory parameters were measured and the extent of lung hyperdensities was assessed using computed tomography. A positive end-expiratory pressure equal to the opening pressure identified on the pressure-volume curve was applied. Tidal volume was reduced until a plateau airway pressure of 25 cm H2O was reached. On the second day, after implementation of permissive hypercapnia, EWO was instituted at a flow of 15 l/min administered during the entire expiratory phase into the trachea through the proximal channel of an endotracheal tube using a ventilator equipped with a special flow generator. Cardiorespiratory parameters were studied under three conditions: permissive hypercapnia, permissive hypercapnia with EWO, and permissive hypercapnia. Results During permissive hypercapnia, EWO decreased PaCO2 from 76 +/- 4 mmHg to 53 +/- 3 mmHg (-30%; P &lt; 0.0001), increased pH from 7.20 +/- 0.03 to 7.34 +/- 0.04 (P &lt; 0.0001), and increased PaO2 from 205 +/- 28 to 296 +/- 38 mmHg (P &lt; 0.05). The reduction in PaCO2 was accompanied by an increase in end-inspiratory plateau pressure from 26 +/- 1 to 32 +/- 2 cm H2O (P = 0.001). Expiratory washout also decreased cardiac index from 4.6 +/- 0.4 to 3.7 +/- 0.3 l.min-1.m-2 (P &lt; 0.01), mean pulmonary arterial pressure from 28 +/- 2 to 25 +/- 2 mmHg (P &lt; 0.01), and true pulmonary shunt from 47 +/- 2 to 36 +/- 3% (P &lt; 0.01). Conclusions Expiratory washout is an effective and easy-to-use ventilatory modality to reduce PaCO2 and increase pH during permissive hypercapnia. However, it significantly increases airway pressures and lung volume through expiratory flow limitation, reexposing some patients to a risk of lung volutrauma if the extrinsic positive end-expiratory pressure is not substantially reduced.

Acute respiratory failure and acute respiratory distress syndrome

2018 ◽  
Author(s):  
Luciano Gattinon ◽  
Eleonora Carlesso
Keyword(s):  
Acute Respiratory Distress Syndrome ◽  
Respiratory Failure ◽  
Respiratory Distress Syndrome ◽  
Respiratory Distress ◽  
Partial Pressure ◽  
Distress Syndrome ◽  
Gas Analysis ◽  
Chronic Obstructive ◽  
Low Oxygen ◽  
Arterial Blood

Respiratory failure (RF) is defined as the acute or chronic impairment of respiratory system function to maintain normal oxygen and CO2 values when breathing room air. ‘Oxygenation failure’ occurs when O2 partial pressure (PaO2) value is lower than the normal predicted values for age and altitude and may be due to ventilation/perfusion mismatch or low oxygen concentration in the inspired air. In contrast, ‘ventilatory failure’ primarily involves CO2 elimination, with arterial CO2 partial pressure (PaCO2) higher than 45 mmHg. The most common causes are exacerbation of chronic obstructive pulmonary disease (COPD), asthma, and neuromuscular fatigue, leading to dyspnoea, tachypnoea, tachycardia, use of accessory muscles of respiration, and altered consciousness. History and arterial blood gas analysis is the easiest way to assess the nature of acute RF and treatment should solve the baseline pathology. In severe cases mechanical ventilation is necessary as a ‘buying time’ therapy. The acute hypoxemic RF arising from widespread diffuse injury to the alveolar-capillary membrane is termed Acute Respiratory Distress Syndrome (ARDS), which is the clinical and radiographic manifestation of acute pulmonary inflammatory states.

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