Arterial and End-Tidal Carbon Dioxide in Supine Obese Patients during General Anesthesia

Kenichi Satoh^1*, Mami Chikuda¹, Ayako Ohashi¹, Miho Kumagai², Masahito Sato¹, Akiyoshi Kuji², Shigeharu Joh¹

¹Division of Dental Anesthesiology, Department of Reconstructive Oral and Maxillofacial Surgery, School of Dentistry, Iwate Medical University, Morioka, Japan.
²Division of Special Care Dentistry, Department of Developmental Oral Health Science, School of Dentistry, Iwate Medical University, Morioka, Japan.

DOI: 10.4236/ojanes.2015.55016                

Abstract

Background: We investigated the differences between partial pressure of arterial carbon dioxide and end-tidal carbon dioxide (P(a-ET)CO₂) with respect to the Broca-Katsura index (BKI), which is an obesity index, in obese patients during general anesthesia. Materials and Methods: From January 2003 to December 2013, we studied 601 patients aged 16 years old or over undergoing general anesthesia. Patients had American Society of Anesthesiology physical status I and II and we reviewed their anesthetic charts. The P(a-ET)CO₂ with respect to the BKI divided patients into two groups: 16 to < 65 years old, and ≥ 65 years old, and compared the P(a-ET)CO₂ values between the two groups. Results: In patients aged 16 to < 65 years old, the mean P(a-ET)CO₂ was 2.2 ± 3.1 mmHg at BKI < 20%; 3.3 ± 3.1 mmHg at 20% < BKI < 40%; and 5.5 ± 5.0 mmHg at 40% < BKI < 60%. In patients aged ≥ 65 years old , the mean P(a-ET)CO₂ was 3.2 ± 4.1 mmHg at BKI < 20%; 4.3 ± 3.6 mmHg at 20% to < 40%; and 4.4 ± 3.3 mmHg at 40% to < 60%. Conclusion: The P(a-ET)CO₂ tends to increase in obese patients during general anesthesia with increasing BKI in patients aged 16 to < 65 years old.

Keywords

Arterial-Alveolar Carbon Dioxide Tension Difference, Broca-Katsura Index, End-Tidal Carbon Dioxide, Partial Pressure of Arterial Carbon Dioxide, Supine Position

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	Campbell, F.A., McLeod, M.E., Bissonnette, B. and Swartz, J.S. (1994) End-Tidal Carbon Dioxide Measurement in Infants and Children during and after General Anaesthesia. Canadian Journal of Anesthesia, 41, 107-110. http://dx.doi.org/10.1007/BF03009801
[2]	Bhavani-Shankar, K., Moseley, H., Kumar, A.Y. and Delph, Y. (1992) Capnometry and Anaesthesia. Canadidan Journal of Anesthesia, 39, 617-632. http://dx.doi.org/10.1007/BF03008330
[3]	Yamauchi, H., Ito, S., Sasano, H., Azami, T., Fisher, J. and Sobue, K. (2011) Dependence of the Gradient between Arterial and End-Tidal PCO2 on the Fraction of Inspired Oxygen. British Journal of Anaesthesia, 107, 631-635. http://dx.doi.org/10.1093/bja/aer171
[4]	Larson Jr., C.P. and Severihnghous, J.W. (1962) Postural Variations in Dead Space and CO2 Gradients Breathing Air and O2. Journal of Applied Physiology, 17, 417-420.
[5]	Tokics, L., Hendenstierna, G., Strandberg, A., Brismar, B. and Lundquist, H. (1987) Lung Collapse and Gas Exchange during General Anesthesia: Effects of Spontaneous Breathing, Muscle Paralysis, and Positive End-Expiratory Pressure. Aneshtesiology, 66, 157-167. http://dx.doi.org/10.1097/00000542-198702000-00009
[6]	Rothen, H.U., Sporre, B., Engberg, G., Wegenius, G. and Hedenstierna, G. (1998) Airway Closure, Atelectasis and Gas Exchange during General Anaesthesia. British Journal of Anaeshtesia, 81, 681-686.
[7]	Omura, M., Zinno, S., Harada, T. and Inoue, N. (1993) Evaluation of Validity of Five Weight-Height Obesity Indices. Fukuoka Igaku Zassi (Hukuoka Acta Medica), 84, 305-310.
[8]	Nishida, M. and Funahashi, T. (2009) Validity of Indices (BMI, Rorre Index, Brocha Method) for Assessment of Obesity. Nihon Rinsho, 67, 301-306.
[9]	Park, W. and Park, S. (2013) Body Shape Analyses of Large Persons in South Korea. Ergonomics, 56, 692-706. http://dx.doi.org/10.1080/00140139.2012.752529
[10]	Nunn, J.F. (1993) Carbon Dioxide. In: Nuun, J.F., Ed., Nuun’s Applied Respiratory Physiology, Butterworth-Heinemann, Cambridge, 219-246. http://dx.doi.org/10.1016/B978-0-7506-1336-1.50016-4
[11]	Suominen, P.K., Staiyer, S., Wang, W. and Chang, A.C. (2007) The Effect of Temperature Correction of Blood Gas Values on the Accuracy of End-Tidal Carbon Dioxide Monitoring in Children after Cardiac Surgery. ASAIO Journal, 53, 670-674. http://dx.doi.org/10.1097/MAT.0b013e3181569bf3
[12]	Nunn, J.F. (1987) Carbon Dioxide. In: Nunn, J.F., Ed., Applied Respiratory Physiology, 3rd Edition, Butterworth, London, 207-234. http://dx.doi.org/10.1016/B978-0-407-00342-2.50015-7
[13]	Russel, G.B. and Graybeal, J.M. (1995) The Arterial to End-Tidal Carbon Dioxide Difference in Neurosurgical Patients during Craniotomy. Anesthesia and Analgesia, 81, 806-810. http://dx.doi.org/10.1097/00000539-199510000-00025
[14]	Bendixen, H.H., Whyte, J. and Laver, M.B. (1963) Impaired Oxygenation in Surgical Patients during General Anesthesia with Controlled Ventilation: A Concept of Atelectasis. The New England Journal of Medicine, 269, 991-996. http://dx.doi.org/10.1056/NEJM196311072691901
[15]	Pelosi, P., Croci, M., Ravagnan, I., Tredici, S., Pedoto, A., Lissoni, A. and Gattinoni, L. (1998) The Effects of Body Mass on Lung Volumes, Respiratory Mechanics, and Gas Exchange during General Anesthesia. Anesthesia and Analgesia, 87, 654-660. http://dx.doi.org/10.1097/00000539-199809000-00031
[16]	Hedensterna, G. and Santesson, J. (1976) Breathing Mechanics, Dead Space and Gas Exchange in the Extremely Obese, Breathing Spontaneously and during Anesthesia with Intermittent Positive Pressure Ventilation. Acta Anaesthesiologica Scandinavica, 20, 248-254. http://dx.doi.org/10.1111/j.1399-6576.1976.tb05036.x