Abstract
Objective
To evaluate agreement with PaCO2 of two low sampling rate sidestream capnometers and a mainstream capnometer in rabbits
and the effect of using high fresh gas flow from a Bain coaxial breathing system.
Study design
Prospective, crossover study.
Animals
A total of 10 New Zealand White rabbits weighing 3.4 ± 0.3 kg [mean ± standard deviation
(SD)].
Methods
Two sidestream analyzers (Viamed VM-2500-S and Capnostream 35) with a sampling rate
of 50 mL minute–1 and a mainstream capnometer (Capnostat 5) were tested. All capnometers used infrared
spectroscopy and advanced microprocessor technology. Rabbits were anesthetized and
intubated with noncuffed endotracheal tubes of 3 mm internal diameter and adequate
seal. A sidestream sampling adapter or the mainstream capnometer was attached to the
endotracheal tube and connected to a Bain coaxial breathing system. Oxygen (1.5 L
minute–1) delivered sevoflurane to maintain anesthesia. An auricular artery catheter allowed
blood sampling for PaCO2 analysis corrected to rectal temperature. Inspired and end-tidal carbon dioxide (Pe′CO2) measurements were recorded during blood sample withdrawal. From each rabbit, 10
paired PaCO2/Pe′CO2 measurements were obtained. Each rabbit was recovered from anesthesia and was anesthetized
again with an alternate capnometer after 1 week. Data were analyzed using Bland–Altman
and two-way anova for repeated measures.
Results
Analysis included 100 paired samples. Negative bias reflects underestimation of PaCO2. Bland–Altman mean (±1.95 SD) was –16.7 (–35.2 to 1.8) mmHg for Capnostat 5, –27.9
(–48.6 to –7.2) mmHg for Viamed, and –18.1 (–34.3 to –1.9) mmHg for Capnostream. Viamed
PaCO2–Pe′CO2 gradient was greater than other two capnometers.
Conclusions
All three capnometers underestimated PaCO2. Capnostat 5 and Capnostream performed similarly.
Clinical relevance
These capnometers underestimated PaCO2 in spontaneously breathing rabbits anesthetized using a Bain coaxial breathing system
with high fresh gas flows.
Keywords
To read this article in full you will need to make a payment
Purchase one-time access:
Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online accessOne-time access price info
- For academic or personal research use, select 'Academic and Personal'
- For corporate R&D use, select 'Corporate R&D Professionals'
Subscribe:
Subscribe to Veterinary Anaesthesia and AnalgesiaAlready a print subscriber? Claim online access
Already an online subscriber? Sign in
Register: Create an account
Institutional Access: Sign in to ScienceDirect
References
- Comparison of Doppler, oscillometric, auricular and carotid arterial blood pressure measurements in isoflurane anesthetized New Zealand white rabbits.J Vet Anaesth Analg. 2014; 41: 393-397
- Mainstream end-tidal carbon dioxide monitoring in ventilated neonates.Singapore Med J. 2008; 49: 199-203
- Measuring agreement in method comparison studies.Stat Methods Med Res. 1999; 8: 135-160
- Sedation and anesthesia of pet rabbits.Clin Tech Small Anim Pract. 1999; 114: 44-49
- Evaluation of a portable oxygen concentrator to provide fresh gas flow to dogs undergoing anesthesia.Can Vet J. 2016; 57: 614-618
- Microstream capnography technology: a new approach to an old problem.J Clin Monit Comput. 1999; 15: 403-409
- Spontaneous ventilation with the Bain anaesthetic system.Br J Anaesth. 1977; 49: 1245-1249
- Coaxial anaesthetic circuits in small animals.J Small Anim Pract. 1989; 30: 294-297
- Monitoring of the ventilatory status of anesthetized birds of prey by using end-tidal carbon dioxide measured with a microstream capnometer.J Zoo Wildl Med. 2007; 38: 1-6
- Gas monitoring.in: Dorsch J.A. Dorsch S.E. Understanding Anesthesia Equipment. 5th edn. Lippincott Williams & Wilkins, USA2008: 686-696
- Basics of monitoring equipment.Can Vet J. 2017; 58: 1200-1208
- Selected drug doses and clinical reference data.in: Manning P.J. Ringler D.H. Newcomer C.E. The biology of the Laboratory Rabbit. 2nd edn. Academic Press, UK1994: 468-472
- Factors influencing capnography in the Bain circuit.J Clin Monit. 1985; 1: 6-10
- The Bain system: gas flows in small subjects.Br J Anaesth. 1978; 50: 127-132
- Infrared measurement of carbon dioxide in the human breath: “breathe-through” devices from Tyndall to the present day.Anesth Analg. 2008; 107: 890-904
- Respiratory gas analysis–technical aspects.Anesth Analg. 2018; 126: 839-845
- Application of end-tidal carbon dioxide monitoring via distal gas samples in ventilated neonates.Pediatr Neonatol. 2017; 58: 370-375
- Fresh gas flow in coaxial Mapleson A and D circuits during spontaneous breathing.Acta Anaesthesiol Scand. 1986; 30: 588-593
- Poor performance of main-stream capnography in newborn infants during general anesthesia.Pediatr Anaesth. 2017; 27: 1235-1240
- Diagnostic accuracy of capnography during high-frequency ventilation in neonatal intensive care units.Pediatr Pulmonol. 2016; 51: 510-516
- A new circuit for small animal anaesthesia: the Bain coaxial circuit.J Am Anim Hosp Assoc. 1979; 15: 61-65
- Using the Bland-Altman method to measure agreement with repeated measures.Br J Anaesth. 2007; 99: 309-311
- Accuracy of expiratory carbon dioxide measurements using the coaxial and circle breathing circuits in small subjects.J Clin Monit. 1985; 1: 149-155
- Sidestream microstream end tidal carbon dioxide measurements and blood gas correlations in neonatal intensive care unit.Pediatr Pulmonol. 2013; 48: 250-256
- End-tidal carbon dioxide monitoring in very low birthweight infants: correlation and agreement with arterial carbon dioxide.Pediatr Pulmonol. 2012; 47: 367-372
Article info
Publication history
Published online: March 09, 2020
Accepted:
February 19,
2020
Received:
November 12,
2019
Identification
Copyright
© 2020 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.
