Typical patterns of expiratory flow and carbon dioxide in mechanically ventilated patients with spontaneous breathing

Comparison of high-flow and conventional nasal cannula oxygen in patients undergoing endobronchial ultrasonography

BACKGROUND

Oxygen therapy is required to prevent hypoxaemia during the endobronchial ultrasonography (EBUS) procedure.

AIMS

To compare the effectiveness of oxygen therapy delivered through high-flow nasal cannula (HFNC) and conventional nasal cannula (CNC) in patients undergoing EBUS. The primary outcome was the proportion of patients who desaturated. Patient compliance and satisfaction were also evaluated.

METHODS

This single-centre prospective interventional study was conducted in a tertiary hospital among patients who presented to the EBUS unit in 2018 and 2019. Patients were randomly assigned to the HFNC group or the CNC group.

RESULTS

The study included 170 patients (111 men and 59 women) with a mean age of 58 ± 14 years. The number of patients experiencing desaturation while receiving oxygen was statistically significantly lower (P < 0.001) in the HFNC group (n = 5) compared with the CNC group (n = 26). Oxygen therapy was adjusted in two patients in the CNC group due to desaturation. Saturation was significantly higher in the HFNC group (P < 0.0001) at the end of the EBUS procedure. Heart rate at the end of EBUS was lower in the HFNC group, but this difference was not statistically significant (96 ± 16 vs 101 ± 19, P = 0.13). Five patients in the HFNC group and 18 patients in the CNC group reported discomfort during the procedure (P = 0.006).

CONCLUSION

Oxygen therapy delivered by HFNC seems to be safer and more effective than by CNC in patients undergoing EBUS. Oxygen therapy with HFNC may be considered as an alternative to CNC because it may increase patient comfort and thereby improve compliance.

Comparison of arterial CO2 estimation by end-tidal and transcutaneous CO2 measurements in intubated children and variability with subject related factors

Transcutaneous PCO₂ (P_TCCO₂) and end-tidal PCO₂ (P_ETCO₂) measurement methods serve as alternatives to arterial PCO₂ (PaCO₂), providing continuous non-invasive monitoring. The objective of this study was to evaluate the P_TCCO₂ and P_ETCO₂ methods with actual PaCO₂ levels, and to assess the variability of measurements in relation to subject-related factors, such as skin and subcutaneous adipose tissue thickness and presence of pulmonary diseases. P_TCCO₂, P_ETCO₂ and PaCO₂ were measured at the same time in intubated pediatric subjects. Subjects' demographic characteristics, clinical features, laboratory parameters, skin and subcutaneous adipose tissue thickness were identified. The study was carried out on 102 subjects with a total of 1118 values for each method. In patients with non-pulmonary disease, the mean difference between P_TCCO₂ and PaCO₂ was - 0.29 mmHg (± 6.05), while it was 0.44 mmHg (± 6.83) bias between P_ETCO₂ and PaCO₂. In those with pulmonary diseases, the mean difference between P_TCCO₂ and PaCO₂ was - 1.27 mmHg (± 8.32), while it was - 4.65 mmHg (± 9.01) between P_ETCO₂ and PaCO₂. Multiple linear regression demonstrated that increased subcutaneous adipose tissue thickness, core body temperature and inotropic index were related with higher P_TCCO₂ values relative to the actual PCO₂ values. Other factors, such as skin tissue thickness, presence of pulmonary disease, measurement location and measurement times were non-significant. The P_TCCO₂ method has higher reliability than the P_ETCO₂ method, and P_TCCO₂ measurements are not influenced by most subject-related factors; however, core body temperature, inotropic index and subcutaneous adipose tissue thickness can lead to significant differences in PCO₂ measurement.

Journal of Clinical Monitoring and Computing 2017 end of year summary: respiration

This paper reviews 32 papers or commentaries published in Journal of Clinical Monitoring and Computing in 2016, within the field of respiration. Papers were published covering airway management, ventilation and respiratory rate monitoring, lung mechanics and gas exchange monitoring, in vitro monitoring of lung mechanics, CO2 monitoring, and respiratory and metabolic monitoring techniques.