The Effect of Different Oxygen Flow Rates on Arterial Oxygenation and End-Tidal CO2 Measurements via a Nasal Cannula in Spinal Anesthesia

We have devised a method for measuring ventilatory muscle endurance as the sustainable inspiratory pressure (SIP), which is the highest pressure a subject can generate in each breath for 10 min. We used a weighted plunger as an inspiratory valve. This both ensures that a constant pressure is generated with each breath and allows the subject to vary his tidal volume freely. Fifteen normal subjects, ages 5--75 yr, had SIP of 82 +/- 6 (SE) cmH2O or 68 +/- 3% of their maximum inspiratory pressure. The respiratory rate was 13 +/- 1 breaths/min with 52 +/- 4% of the respiratory cycle spent in inspiration; end-tidal CO2 pressure increased by 3.3 +/- 1.0 Torr during runs at SIP. Oxygen consumption measured in two subjects rose with increasing pressure below SIP. There was no further increase in oxygen consumption when these subjects breathed with inspiratory pressures above SIP. Our method allows reproducible measurement of ventilatory muscle endurance without dependence on the subject's flow rates or the resistance chosen.

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The Effect of Different Oxygen Flow Rates via Nasal Cannula in Recovery Room after Pectus Excavatum by the Nuss Procedure

Soonchunhyang Medical Science ◽

10.15746/sms.17.004 ◽

2017 ◽

Vol 23 (1) ◽

pp. 20-24

Author(s):

Yonghan Seo ◽

Jin Hun Chung ◽

Minyoung Jeong ◽

Hyungyoun Gong

Keyword(s):

Recovery Room ◽

Pectus Excavatum ◽

Nasal Cannula ◽

Oxygen Flow ◽

Nuss Procedure ◽

Flow Rates

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Addition of nasal cannula can either impair or enhance preoxygenation with a bag valve mask: A randomized crossover design study comparing oxygen flow rates

Journal of Emergency Medicine ◽

10.1016/j.jemermed.2018.04.039 ◽

2018 ◽

Vol 54 (6) ◽

pp. 898-899

Author(s):

Paul A. Leccese

Keyword(s):

Crossover Design ◽

Nasal Cannula ◽

Oxygen Flow ◽

Design Study ◽

Flow Rates

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Abstract 235: End-Tidal CO2 Monitoring in Non-Intubated Traumatic Brain Injury Patients Receiving O2 via Nasal Cannula vs. Non-Rebreather Mask

Circulation ◽

10.1161/circ.138.suppl_2.235 ◽

2018 ◽

Vol 138 (Suppl_2) ◽

Author(s):

Bruce J Barnhart ◽

Daniel W Spaite ◽

Eric Helfenbein ◽

Saeed Babaeizadeh ◽

Dawn B Jorgenson ◽

...

Keyword(s):

Traumatic Brain Injury ◽

Brain Injury ◽

Nasal Cannula ◽

Delivery Methods ◽

Co2 Monitoring ◽

The Mean ◽

Clinically Significant ◽

End Tidal ◽

O2 Delivery ◽

End Tidal Co2

Background: The advent of highly sensitive End-Tidal CO2 (ETCO2) sensors allows effective monitoring of intubated patients in many emergency care settings, including EMS. Previous work has explored the use of ETCO2 monitoring in non-intubated patients with sensors placed in the nares. However, nothing is known about the effect of passive oxygen delivery [nasal cannula (NC) or non-rebreather mask (NRB)] on ETCO2 measurement. Objective: To compare ETCO2 measurements in non-intubated Traumatic Brain Injury (TBI) patients receiving O2 via NC vs NRB in the prehospital setting. Methods: A subset of major TBI cases (CDC Barell Matrix Type-1) in the Excellence in Prehospital Injury Care (EPIC) TBI Study (NIH/NINDS-1R01NS071049; ClinicalTrials.gov-NCT01339702) were evaluated 4/13-3/17). Non-intubated cases from 6 EMS agencies providing monitor data (Philips MRx) were included when continuous ETCO2 data were available. Statistics: Two-tailed t test, α = 0.05. Results: The 104 included cases had median age of 50.5 (range: 9-91; male: 67%). 39 (37.5%) received O2 via NC and 65 (62.5%) via NRB. Mean ETCO2: NC cases: 27.7 mmHg (95% CI: 25.7, 29.8); NRB: 30.0 (28.1, 31.8; p=0.132). There were also no significant differences among the mean lowest recorded values (p=0.449) or the mean highest values (p=0.275). Conclusion: We believe this is the first report comparing ETCO2 values based upon the method of passive O2 delivery in non-intubated patients. The minor differences between NC vs NRB-oxygenated patients was neither statistically nor clinically significant. This is surprising since: 1) the O2 flow rates and 2) the open-air (NC) vs mask (NRB) delivery methods are so dramatically different. Future study is needed to identify the clinical implications of using noninvasive ETCO2 measurement as a tool for monitoring ventilatory status and changes in non-intubated TBI (and other) patients.

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Assessment of the Use of Humidified Nasal Cannulas for Oxygen Therapy in Patients with Epistaxis

ORL ◽

10.1159/000514460 ◽

2021 ◽

pp. 1-5

Author(s):

Jingjing Liu ◽

Tengfang Chen ◽

Zhenggang Lv ◽

Dezhong Wu

Keyword(s):

Flow Rate ◽

Oxygen Therapy ◽

Preliminary Investigation ◽

Nasal Cannula ◽

Low Flow ◽

Antiplatelet Drugs ◽

Flow Rates ◽

The Past ◽

Oxygen Inhalation ◽

Significant Difference

Introduction: In China, nasal cannula oxygen therapy is typically humidified. However, it is difficult to decide whether to suspend nasal cannula oxygen inhalation after the nosebleed has temporarily stopped. Therefore, we conducted a preliminary investigation on whether the use of humidified nasal cannulas in our hospital increases the incidence of epistaxis. Methods: We conducted a survey of 176,058 inpatients in our hospital and other city branches of our hospital over the past 3 years and obtained information concerning their use of humidified nasal cannulas for oxygen inhalation, nonhumidified nasal cannulas, anticoagulant and antiplatelet drugs, and oxygen inhalation flow rates. This information was compared with the data collected at consultation for epistaxis during these 3 years. Results: No significant difference was found between inpatients with humidified nasal cannulas and those without nasal cannula oxygen therapy in the incidence of consultations due to epistaxis (χ2 = 1.007, p > 0.05). The same trend was observed among hospitalized patients using anticoagulant and antiplatelet drugs (χ2 = 2.082, p > 0.05). Among the patients with an inhaled oxygen flow rate ≥5 L/min, the incidence of ear-nose-throat (ENT) consultations due to epistaxis was 0. No statistically significant difference was found between inpatients with a humidified oxygen inhalation flow rate <5 L/min and those without nasal cannula oxygen therapy in the incidence of ENT consultations due to epistaxis (χ2 = 0.838, p > 0.05). A statistically significant difference was observed in the incidence of ENT consultations due to epistaxis between the low-flow nonhumidified nasal cannula and nonnasal cannula oxygen inhalation groups (χ2 = 18.428, p < 0.001). The same trend was observed between the 2 groups of low-flow humidified and low-flow nonhumidified nasal cannula oxygen inhalation (χ2 = 26.194, p < 0.001). Discussion/Conclusion: Neither high-flow humidified nasal cannula oxygen inhalation nor low-flow humidified nasal cannula oxygen inhalation will increase the incidence of recurrent or serious epistaxis complications; the same trend was observed for patients who use anticoagulant and antiplatelet drugs. Humidification during low-flow nasal cannula oxygen inhalation can prevent severe and repeated epistaxis to a certain extent.

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Cardiorespiratory Functioning in Youth with Persistent Post-Concussion Symptoms: A Pilot Study

Journal of Clinical Medicine ◽

10.3390/jcm10040561 ◽

2021 ◽

Vol 10 (4) ◽

pp. 561

Author(s):

Aliyah Snyder ◽

Christopher Sheridan ◽

Alexandra Tanner ◽

Kevin Bickart ◽

Molly Sullan ◽

...

Keyword(s):

Processing Speed ◽

Mean Value ◽

Exhaled Breath ◽

Post Injury ◽

The Past ◽

Neurobehavioral Outcomes ◽

End Tidal ◽

Relationship Of ◽

The Relationship ◽

End Tidal Co2

Dysregulation of the autonomic nervous system (ANS) may play an important role in the development and maintenance of persistent post-concussive symptoms (PPCS). Post-injury breathing dysfunction, which is influenced by the ANS, has not been well-studied in youth. This study evaluated cardiorespiratory functioning at baseline in youth patients with PPCS and examined the relationship of cardiorespiratory variables with neurobehavioral outcomes. Participants were between the ages of 13–25 in two groups: (1) Patients with PPCS (concussion within the past 2–16 months; n = 13) and (2) non-injured controls (n = 12). Capnometry was used to obtain end-tidal CO2 (EtCO2), oxygen saturation (SaO2), respiration rate (RR), and pulse rate (PR) at seated rest. PPCS participants exhibited a reduced mean value of EtCO2 in exhaled breath (M = 36.3 mmHg, SD = 2.86 mmHg) and an altered inter-correlation between EtCO2 and RR compared to controls. Neurobehavioral outcomes including depression, severity of self-reported concussion symptoms, cognitive catastrophizing, and psychomotor processing speed were correlated with cardiorespiratory variables when the groups were combined. Overall, results from this study suggest that breathing dynamics may be altered in youth with PPCS and that cardiorespiratory outcomes could be related to a dimension of neurobehavioral outcomes associated with poorer recovery from concussion.

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