Levels of end-tidal carbon dioxide are low despite normal respiratory rate in individuals with Long COVID

In this study, we compared the effects of xylazine, medetomidine and dexmedetomidine in combination with ketamine on heart rate, respiratory rate, blood gas values, temperature and sedation scores. A total of 30 dogs were evaluated. The dogs were randomly allocated into three anaesthesia groups, each of which included ten dogs. The first group, denoted the xylazine/ketamine group, intravenously received xylazine (0.5 mg/kg) for premedication and ketamine (5 mg/kg) for induction. The second group, the medetomidine/ketamine group, intravenously received medetomidine (10 µg/kg) followed by ketamine (5 mg/kg). The third group received the dexmedetomidine/ketamine combination. This group intravenously received dexmedetomidine (3 µg/kg) for premedication and ketamine (5 mg/kg). Heart rate, respiratory rate, oxygen saturation, blood gas parameters and temperature were recorded for all patients immediately before sedation onset (T0), five minutes after sedation onset (T1) and five minutes after endotracheal intubation following ketamine injection (T2). The end tidal carbon dioxide level was recorded at T2. A significant decrease in heart rate occurred following premedication in all groups. However, the decrease was most marked in the medetomidine/ketamine group. An increase was observed in venous partial pressure of carbon dioxide values at T2 in the xylazine/ketamine group compared to the medetomidine/ketamine and dexmedetomidine/ketamine groups. The end tidal carbon dioxide levels were higher in the medetomidine/ketamine group than in the other two groups, and oxygen saturation of haemoglobin levels in the same group were found to be lower than in the others. It was determined that none of α2-agonists, namely xylazine, medetomidine or dexmedetomidine, had superior properties over the others. If medetomidine is used, special care should be taken because of the rapid decrease in heart rate.

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A pharmacodynamic model of respiratory rate and end-tidal carbon dioxide values during anesthesia in children

Acta Pharmacologica Sinica ◽

10.1038/s41401-018-0156-x ◽

2018 ◽

Vol 40 (5) ◽

pp. 642-647 ◽

Cited By ~ 1

Author(s):

Ji-Hyun Lee ◽

Pyo-Yoon Kang ◽

Young-Eun Jang ◽

Eun-Hee Kim ◽

Jin-Tae Kim ◽

...

Keyword(s):

Carbon Dioxide ◽

Respiratory Rate ◽

Pharmacodynamic Model ◽

End Tidal Carbon Dioxide ◽

End Tidal

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Caffeine and Cerebral Blood Flow

The British Journal of Psychiatry ◽

10.1192/bjp.143.6.604 ◽

1983 ◽

Vol 143 (6) ◽

pp. 604-608 ◽

Cited By ~ 49

Author(s):

Roy J. Mathew ◽

Deborah L. Barr ◽

Maxine L. Weinman

Keyword(s):

Carbon Dioxide ◽

Blood Pressure ◽

Blood Flow ◽

Cerebral Blood Flow ◽

Respiratory Rate ◽

Regional Cerebral Blood Flow ◽

Inhalation Technique ◽

Regional Cerebral Blood ◽

End Tidal Carbon Dioxide ◽

End Tidal

SummaryTwo groups of normal volunteers had regional cerebral blood flow (rCBF) measured, by the 133Xenon inhalation technique, before and 30 minutes after 250 mg or 500 mg caffeine given orally. rCBF was measured in a third group of subjects, twice, at a similar interval under identical laboratory conditions. Subjects who received caffeine showed significant decreases in rCBF while the others showed no rCBF change from the first to the second measurement. However, the two caffeine groups did not differ in degrees of rCBF reduction. There were no regional variations in the post-caffeine decrease in cerebral blood flow. The three groups did not show significant changes in end-tidal carbon dioxide, pulse rate, blood pressure, forehead skin temperature and respiratory rate.

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Modifying reusable elastomeric respirators to utilise breathing system filters with 3D printed adapters, a safe alternative to N95 during COVID-19

10.1101/2020.04.10.20061291 ◽

2020 ◽

Cited By ~ 1

Author(s):

D.C.Y. Liu ◽

T.H. Koo ◽

J.K.K. Wong ◽

Y.H. Wong ◽

K.S.C. Fung ◽

...

Keyword(s):

Carbon Dioxide ◽

Respiratory Rate ◽

Breathing System ◽

Safe Alternative ◽

End Tidal Carbon Dioxide ◽

Before And After ◽

The Face ◽

3D Printed ◽

The Mean ◽

End Tidal

SummaryThe COVID-19 pandemic has caused a worldwide shortage of personal protective equipment including N95 and FFP3 respirators. Reusable elastomeric respirators are suitable alternatives when used with compatible filters. These filters may be difficult to source and elastomeric respirators are not recommended for surgical use as the exhaled air is not filtered. Breathing system filters are routinely used in anaesthetic circuits to filter virus and bacteria. In this study, we designed 3D printed adapters that allowed elastomeric respirators to utilise breathing system filters and made simple modifications to the respirators to filter exhaled breaths. We then evaluated the performance and safety of our modified elastomeric respirators with quantitative fit tests.We recruited 8 volunteers to perform quantitative fit tests. Fit factors, respiratory rate and end-tidal carbon dioxide were recorded before and after wearing the modified respirators for 1 hour. All 8 volunteers obtained fit factors of 200+, the maximum achievable, for all tests exercises in all fit tests. The mean (range) end-tidal carbon dioxide was 4.5 (3.9-5.5) kPa and 4.6 (range 4.1-5.3) kPa before and after 1 hour of usage. The mean (range) respiratory rate was 16.5 (11-24) min-1 and 17.4 (15-22) min-1 before and after 1 hour of usage. Four (50%) did not experience any subjective discomfort while 2 (25%) reported pressure on the face, 1 (12.5%) reported exhalation resistance and 1 (12.5%) reported transient dizziness with exertion. Breathing system filters combined with properly fitted reusable elastomeric respirators is a safe alternative to N95 during the COVID-19 pandemic.

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Squamous Papilloma Causing Airway Obstruction During Conscious Sedation

Anesthesia Progress ◽

10.2344/anpr-64-03-07 ◽

2017 ◽

Vol 64 (3) ◽

pp. 168-170

Author(s):

Paul Brady ◽

Christine McCreary ◽

Ken D. O'Halloran ◽

Catherine Gallagher

Keyword(s):

Carbon Dioxide ◽

Oxygen Saturation ◽

Airway Obstruction ◽

Respiratory Rate ◽

Respiratory Depression ◽

Conscious Sedation ◽

Monitoring Tool ◽

Squamous Papilloma ◽

End Tidal Carbon Dioxide ◽

End Tidal

Monitoring for respiratory depression is essential during conscious sedation. We report a case of a squamous papilloma as an unusual cause of intermittent partial airway obstruction in a 43-year-old man undergoing intravenous conscious sedation with midazolam. The Integrated Pulmonary Index (IPI) is an algorithm included in some commercially available monitors that constitutes a representation of 4 parameters: end-tidal carbon dioxide, respiratory rate, oxygen saturation, and pulse rate. We discuss the potential of the IPI as a monitoring tool during sedation.

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The Effect Of Respiratory Rate And Obstructive Pulmonary Disease On Arterial Carbon Dioxide To End-tidal Carbon Dioxide Gradient (PaCO2- PetCO2) In A Population Of Emergency Department Patients

10.1164/ajrccm-conference.2010.181.1_meetingabstracts.a4569 ◽

2010 ◽

Author(s):

Rebecca Sell ◽

Daniel P. Davis

Keyword(s):

Carbon Dioxide ◽

Emergency Department ◽

Respiratory Rate ◽

Pulmonary Disease ◽

Obstructive Pulmonary Disease ◽

Arterial Carbon Dioxide ◽

End Tidal Carbon Dioxide ◽

Emergency Department Patients ◽

End Tidal

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Evaluation of cardiorespiratory parameters in dogs undergoing laparoscopic versus open gonadectomy with spontaneous ventilation anaesthesia: a pilot study

Journal of Veterinary Healthcare ◽

10.14302/issn.2575-1212.jvhc-20-3256 ◽

2020 ◽

Vol 2 (2) ◽

pp. 1-9

Author(s):

Fabrizio di Virgilio ◽

Sara Manfredini ◽

Luca Formaggini

Keyword(s):

Carbon Dioxide ◽

Heart Rate ◽

Laparoscopic Surgery ◽

Pilot Study ◽

Oxygen Saturation ◽

Respiratory Rate ◽

Spontaneous Ventilation ◽

Invasive Technique ◽

End Tidal Carbon Dioxide ◽

End Tidal

This pilot study aims to compare cardiorespiratory parameters in female dogs that underwent either laparoscopic or open elective gonadectomy with spontaneous ventilation anaesthesia. Records of 77 client-owned female dogs were reviewed. Patients were divided into two groups: laparoscopic surgery (L group, n 47) and open abdominal surgery (O group, n 30). The end-tidal carbon dioxide, respiratory rate, oxygen saturation, heart rate, non-invasive arterial blood pressure and length of procedure were recorded and statistically evaluated. Once normality of the sample data has been assessed, equality between the groups was analysed with two-sample Student’s or Welch’s t-test, whether the hypothesis of variance equality, through an F-test, was verified or not. A value of p <0.05 was considered statistically significant. No statistically significant difference was found between groups regarding the end-tidal carbon dioxide, oxygen saturation, respiratory rate, heart rate, systolic and medium arterial pressure values. Mean diastolic pressure was lower in the L group. The procedure length between the two groups was statistically different: laparoscopy was shorter than open surgery. In spontaneously ventilating female dogs, the cardiorespiratory parameters evaluated seem not to be affected by the presence of pneumoperitoneum when intrabdominal pressure is kept between 8 and 10 mmHg. The pilot nature of the study and the shorter laparoscopic surgery length could bias these results. However, in the author’s opinion, these findings confirm the interest of laparoscopy and the small impact of this mini-invasive technique in healthy patients.

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