Short-Term Effects of Humidification Devices on Respiratory Pattern and Arterial Blood Gases During Noninvasive Ventilation

Abstract Background There is growing interest towards the use of helmet noninvasive ventilation (NIV) for the management of acute hypoxemic respiratory failure. Gas conditioning through heat and moisture exchangers (HME) or heated humidifiers (HHs) is needed during facemask NIV to provide a minimum level of humidity in the inspired gas (15 mg H2O/L). The optimal gas conditioning strategy during helmet NIV remains to be established. Methods Twenty patients with acute hypoxemic respiratory failure (PaO2/FiO2 < 300 mmHg) underwent consecutive 1-h periods of helmet NIV (PEEP 12 cmH2O, pressure support 12 cmH2O) with four humidification settings, applied in a random order: double-tube circuit with HHs and temperature set at 34 °C (HH34) and 37 °C (HH37); Y-piece circuit with HME; double-tube circuit with no humidification (NoH). Temperature and humidity of inhaled gas were measured through a capacitive hygrometer. Arterial blood gases, discomfort and dyspnea through visual analog scales (VAS), esophageal pressure swings (ΔPES) and simplified pressure–time product (PTPES), dynamic transpulmonary driving pressure (ΔPL) and asynchrony index were measured in each step. Results Median [IqR] absolute humidity, temperature and VAS discomfort were significantly lower during NoH vs. HME, HH34 and HH37: absolute humidity (mgH2O/L) 16 [12–19] vs. 28 [23–31] vs. 28 [24–31] vs. 33 [29–38], p < 0.001; temperature (°C) 29 [28–30] vs. 30 [29–31] vs. 31 [29–32] vs 32. [31–33], p < 0.001; VAS discomfort 4 [2–6] vs. 6 [2–7] vs. 7 [4–8] vs. 8 [4–10], p = 0.03. VAS discomfort increased with higher absolute humidity (p < 0.01) and temperature (p = 0.007). Higher VAS discomfort was associated with increased VAS dyspnea (p = 0.001). Arterial blood gases, respiratory rate, ΔPES, PTPES and ΔPL were similar in all conditions. Overall asynchrony index was similar in all steps, but autotriggering rate was lower during NoH and HME (p = 0.03). Conclusions During 1-h sessions of helmet NIV in patients with hypoxemic respiratory failure, a double-tube circuit with no humidification allowed adequate conditioning of inspired gas, optimized comfort and improved patient–ventilator interaction. Use of HHs or HME in this setting resulted in increased discomfort due to excessive heat and humidity in the interface, which was associated with more intense dyspnea. Trail Registration Registered on clinicaltrials.gov (NCT02875379) on August 23rd, 2016.

Download Full-text

Monitoring of noninvasive ventilation: comparative analysis of different strategies

Respiratory Research ◽

10.1186/s12931-020-01586-8 ◽

2020 ◽

Vol 21 (1) ◽

Author(s):

Marjolaine Georges ◽

Claudio Rabec ◽

Elise Monin ◽

Serge Aho ◽

Guillaume Beltramo ◽

...

Keyword(s):

Noninvasive Ventilation ◽

Gold Standard ◽

Ventilatory Support ◽

Blood Gases ◽

Institutional Review Board ◽

Arterial Blood Gases ◽

Arterial Blood ◽

Institutional Review ◽

Combining Data ◽

Retrospective Comparative Study

Abstract Background Noninvasive ventilation (NIV) represents an effective treatment for chronic respiratory failure. However, empirically determined NIV settings may not achieve optimal ventilatory support. Therefore, the efficacy of NIV should be systematically monitored. The minimal recommended monitoring strategy includes clinical assessment, arterial blood gases (ABG) and nocturnal transcutaneous pulsed oxygen saturation (SpO2). Polysomnography is a theoretical gold standard but is not routinely available in many centers. Simple tools such as transcutaneous capnography (TcPCO2) or ventilator built-in software provide reliable informations but their role in NIV monitoring has yet to be defined. The aim of our work was to compare the accuracy of different combinations of tests to assess NIV efficacy. Methods This retrospective comparative study evaluated the efficacy of NIV in consecutive patients through four strategies (A, B, C and D) using four different tools in various combinations. These tools included morning ABG, nocturnal SpO2, TcPCO2 and data provided by built-in software via a dedicated module. Strategy A (ABG + nocturnal SpO2), B (nocturnal SpO2 + TcPCO2) and C (TcPCO2 + builtin software) were compared to strategy D, which combined all four tools (NIV was appropriate if all four tools were normal). Results NIV was appropriate in only 29 of the 100 included patients. Strategy A considered 53 patients as appropriately ventilated. Strategy B considered 48 patients as appropriately ventilated. Strategy C misclassified only 6 patients with daytime hypercapnia. Conclusion Monitoring ABG and nocturnal SpO2 is not enough to assess NIV efficacy. Combining data from ventilator built-in software and TcPCO2 seems to represent the best strategy to detect poor NIV efficacy. Trialregistration Institutional Review Board of the Société de Pneumologie de Langue Française (CEPRO 2016 Georges)

Download Full-text

Ventilation and respiratory pattern and timing in resting awake cats

Canadian Journal of Physiology and Pharmacology ◽

10.1139/y85-026 ◽

1985 ◽

Vol 63 (2) ◽

pp. 148-154 ◽

Cited By ~ 14

Author(s):

D. B. Jennings ◽

P. C. Szlyk

Keyword(s):

Tidal Volume ◽

Normal Control ◽

Blood Gases ◽

Bimodal Distribution ◽

Inspiratory Flow ◽

Respiratory Pattern ◽

Respiratory Drive ◽

Arterial Blood Gases ◽

Arterial Blood ◽

Awake Cats

The purpose of this study was to characterize the variability and patterns of spontaneous respiratory behaviour in awake cats. Respiration was measured in six cats over 80 or 90 min by the plethysmographic technique. In three cats, arterial blood gases were measured. Breath frequency (f) and tidal volume (VT) varied considerably breath-to-breath, although on average, these measurements as well as average ventilation remained relatively constant. The incidence of breath ventilation (VT × 60/TTOT) and VT were distributed unimodally but the incidence of breath f had a bimodal distribution. In the low f range, average f was 22.5 breaths/min, and in the high f range, average f was 41.6 breaths/min. The latter range appeared to be associated with purring. Inspiratory duration (TI) was less than expiratory duration (TE) at low f but exceeded TE at high f. For a given breath ventilation there was a predictable f and VT. At shorter TI (higher f) mean inspiratory flow, an index of central respiratory drive, increased but VT decreased. This study indicates that "normal" control respiratory behaviour in awake cats is better described by the range and pattern of breathing than by average values.

Download Full-text

VOX Index– A New Parameter Using Ultrasound to Predict Time of Applying Noninvasive Ventilation

10.21203/rs.3.rs-102977/v1 ◽

2020 ◽

Author(s):

Ruoxuan Wen ◽

Xingshuo Hu ◽

Zhimei Duan ◽

Han Fu ◽

Hongjun Gu ◽

...

Keyword(s):

Noninvasive Ventilation ◽

Assessment Tool ◽

Medical Center ◽

Oxygenation Index ◽

Blood Gases ◽

Low Flow ◽

Arterial Blood Gases ◽

Icu Patients ◽

Arterial Blood ◽

Movement Distance

Abstract Background: Physicians have been utilizing respiratory status and arterial blood gases measurements of the patient for determining the need of noninvasive ventilation (NIV). There is actually no clear and accurate index to assess the appropriate time of using NIV. We hypothesized that diaphragmatic ultrasound in combination with arterial blood gases test can accurately predict when the patients require sequential NIV.Objective: To investigate the feasibility of using the new VOX (velocity oxygenation) index, combining the diaphragmatic ultrasound and oxygen pressure analyses, as a reliable assessment tool for sequential NIV in intensive care unit (ICU) patients. Method: A prospective study including patients admitted to ICU of People’s Liberation Army General Hospital First Medical Center Respiratory Department between August 1st 2018 and March 31st 2020. Patients received either continuous low-flow oxygen therapy or sequential NIV based on the physician judgement. The diaphragm movement distance, contraction time, and velocity were recorded and the E-T (excursion-time) index, VOX index, and arterial blood gases were compared. Result: The velocity of the diaphragmatic contraction (VD) was higher (3.29 vs. 1.89, P< 0.001) and P/F ratio was lower (161 vs. 264, P< 0.001) in patients receiving NIV. In predicting the need of utilizing NIV, VOX index showed the largest area under curve of ROC (AUC= 0.97) which was significantly greater than the AUC of VD and P/F ratio.Conclusion: VOX index serves as an accurate indicator of predicting the time of using NIV for ICU patients. It is recommended to switch from invasive ventilation to NIV when VOX< 109.89.

Download Full-text

Immediate and short-term outcome of septoplasty with nasal packing with reference to the effect of arterial blood gases’ concentrations

Al-Azhar Assiut Medical Journal ◽

10.4103/azmj.azmj_26_18 ◽

2018 ◽

Vol 16 (4) ◽

pp. 333

Author(s):

MohamedA Fatahalla ◽

AshrafA Wahba ◽

MahmoudM Elsayed

Keyword(s):

Blood Gases ◽

Nasal Packing ◽

Arterial Blood Gases ◽

Short Term ◽

Term Outcome ◽

Arterial Blood ◽

Short Term Outcome

Download Full-text

Precision of arterial blood gases and cutaneous oxygen saturation in healthy non-smokers

Scandinavian Journal of Clinical and Laboratory Investigation ◽

10.3109/00365518909089093 ◽

1989 ◽

Vol 49 (3) ◽

pp. 265-268 ◽

Cited By ~ 2

Author(s):

J. A. Grebstad ◽

L. Svendsen ◽

A. Gulsvik

Keyword(s):

Oxygen Saturation ◽

Blood Gases ◽

Arterial Blood Gases ◽

Arterial Blood

Download Full-text

Pathophysiology and clinical consequences of arterial blood gases and pH after cardiac arrest

Intensive Care Medicine Experimental ◽

10.1186/s40635-020-00307-1 ◽

2020 ◽

Vol 8 (S1) ◽

Author(s):

Chiara Robba ◽

Dorota Siwicka-Gieroba ◽

Andras Sikter ◽

Denise Battaglini ◽

Wojciech Dąbrowski ◽

...

Keyword(s):

Carbon Dioxide ◽

Mechanical Ventilation ◽

Cardiac Arrest ◽

Oxygen Demand ◽

Blood Gases ◽

Metabolic Energy ◽

High Morbidity ◽

Arterial Blood Gases ◽

Arterial Blood ◽

Clinical Consequences

AbstractPost cardiac arrest syndrome is associated with high morbidity and mortality, which is related not only to a poor neurological outcome but also to respiratory and cardiovascular dysfunctions. The control of gas exchange, and in particular oxygenation and carbon dioxide levels, is fundamental in mechanically ventilated patients after resuscitation, as arterial blood gases derangement might have important effects on the cerebral blood flow and systemic physiology.In particular, the pathophysiological role of carbon dioxide (CO2) levels is strongly underestimated, as its alterations quickly affect also the changes of intracellular pH, and consequently influence metabolic energy and oxygen demand. Hypo/hypercapnia, as well as mechanical ventilation during and after resuscitation, can affect CO2 levels and trigger a dangerous pathophysiological vicious circle related to the relationship between pH, cellular demand, and catecholamine levels. The developing hypocapnia can nullify the beneficial effects of the hypothermia. The aim of this review was to describe the pathophysiology and clinical consequences of arterial blood gases and pH after cardiac arrest.According to our findings, the optimal ventilator strategies in post cardiac arrest patients are not fully understood, and oxygen and carbon dioxide targets should take in consideration a complex pattern of pathophysiological factors. Further studies are warranted to define the optimal settings of mechanical ventilation in patients after cardiac arrest.

Download Full-text

Arterial blood gases during maximum metabolic demands: Patterns across the vertebrate spectrum

Comparative Biochemistry and Physiology Part A Molecular & Integrative Physiology ◽

10.1016/j.cbpa.2020.110888 ◽

2020 ◽

pp. 110888

Author(s):

James W. Hicks ◽

Tobias Wang

Keyword(s):

Blood Gases ◽

Arterial Blood Gases ◽

Arterial Blood

Download Full-text

Arterial Blood Gases in Pranayama Practice

Perceptual and Motor Skills ◽

10.2466/pms.1978.46.1.171 ◽

1978 ◽

Vol 46 (1) ◽

pp. 171-174 ◽

Cited By ~ 3

Author(s):

V. Pratap ◽

W. H. Berrettini ◽

C. Smith

Keyword(s):

Blood Gases ◽

Neural Mechanism ◽

Arterial Blood Gases ◽

Arterial Blood ◽

Yogic Breathing ◽

The Mind ◽

Calming Effect

Pranayama is a Yogic breathing practice which is known experientially to produce a profound calming effect on the mind. In an experiment designed to determine whether the mental effects of this practice were accompanied by changes in the arterial blood gases, arterial blood was drawn from 10 trained individuals prior to and immediately after Pranayama practice. No significant changes in arterial blood gases were noted after Pranayama. A neural mechanism for the mental effects of this practice is proposed.

Download Full-text