Abstract
Objective
To evaluate the relationship between PaCO2 and end-tidal CO2 tension (PetCO2) before weaning and during a weaning trial and to determine the ability of PetCO2 to identify clinically relevant episodes of hypercapnia.
Design
Open, prospective study.
Patients
30 critically ill patients (mean age 63±2 years; Acute Physiology And Chronic Health Evaluation (APACHE) II of 18.4±3) who underwent a weaning trial during the recovery phase of acute respiratory failure requiring mechanical ventilation (MV) (8.9±1 days on MV).
Interventions
Weaning trial consisted of 2 h breathing on 5 cmH2O of Continuous Positive Airway Pressure (CPAP).
Measurements and results
Arterial blood gas values, PetCO2 register and pulse oximetry determinations were recorded in assist/control ventilation before CPAP, after 1 h on CPAP and after 2 h on CPAP (immediately before extubation) or immediately before returning to assist/control mode in patients who failed the weaning trial. Clinically relevant hypercapnic episodes were described as: (1) an increment in PaCO2>42 mm Hg in previously normocapnic patients and (2) an increment of >8 mm Hg from previous PaCO2 in previously hypercapnic patients. Changes, in PaCO2 and changes in PetCO2 between MV and the first and second hour of CPAP showed a significant correlation (r=0.74;p<0.01). Clinically relevant hypercapnic episodes were detected by increments of >3 mm Hg in PetCO2 with a sensitivity of 82%, a specificity of 76% and a negative predictive value of 94%. The area under the receiver operating characteristic curve for increments in PetCO2 was 0.90.
Conclusions
Capnography provided good assessment of hypercapnic episodes during weaning although the high number of false positives may result in arterial blood sampling in patients who do not present with ventilation failure.
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
References
Hess D (1993) Capnography: technical aspects and clinical applications. In: Kacrnareck RM, Hess D, Stoller JK (eds) Monitoring in respiratory care. Mosby, St. Louis, Mo., pp. 375–405
Stock MC (1988) Noninvasive carbon dioxide monitoring. Crit Care Clin 4:511–526
Clark JS, Votteri B, Ariagno RL, Cheung P, Eichhorn JH, Fallat R, Lee SE, Newth CJL, Rotman H, Sue DY (1992) Noninvasive assessment of blood gases. Am. Rev Respir Dis 145:220–232
Donati F, Maille, J, Blain R, Boulanger M, Sahab P (1985) End-tidal carbon dioxide tension and temperature changes after coronary artery bypass surgery. Can Anaesth Soc J 32:272–277
Russell GB, Graybeal JM (1990) Stability of arterial to end-tidal carbon dioxide gradients during postoperative cardio-respiratory support. Can J Anaesth 37:560–566
Blanch LI, Fernandez R, Artigas A (1991) The effect of autoPEEP on the PaCO2-PetCO2 gradient and expired CO2 slope in critically ill patients during total ventilatory support. J Crit Care 6:202–210
Hoffman RA, Krieger BP, Kramer MR, Segel S, Bizousky F, Gazeroglu H, Sacker MA (1989) End-tidal carbon dioxide in critically ill patients during changes in mechanical ventilation. Am Rev Respir Dis 140:1265–1268
Niehoff J, DelGuercio C, LaMorte W, Hughes-Grasberger SL, Heard S, Dennis R, Yeston N (1988) Efficacy of pulse oximetry and capnometry in postoperative ventilatory weaning. Crit Care Med 16:701–705
Withington DE, Ramsay JG, Saoud AT, Bilodeau J (1991) Weaning from ventilation after cardio-pulmonary bypass: evaluation of a non-invasive technique. Can J Anaesth 38:15–19
Healey CJ, Fedullo AJ, Swinburne AJ, Wahl GW (1987) Comparison of noninvasive measurements of carbon dioxide tension during withdrawal from mechanical ventilation. Crit Care Med 15:764–768
Hess D, Schlottag A, Levin B, Mathai J, Rexrode WO (1991) An evaluation of the usefulness of end-tidal PCO2 to aid weaning from mechanical ventilation following cardiac surgery. Respir Care 36:837–843
Morley TF, Giaimo J, Maroszan E, Bermingham J, Gordon R, Griesback R, Zappasodi SJ, Giudice JC (1993) Use of capnography for assessment of the adequacy of alveolar ventilation during weaning from mechanical ventilation. Am Rev Respir Dis 148:339–344
Bailar JC III, Mosteller F (1992) Medical technology assessment. In: Bailar JC III, Mosteller F (eds) Medical uses of statistics. NEJM Books, Boston, Mass, pp. 393–411
Jubran A, Tobin MJ (1994) Use of flowvolume curves in detecting secretions in ventilator-dependent patients. Am J Respir Crit Care Med 150:766–769
Hanley JA, McNeil BJ (1983) A method of comparing the areas under receiver operating characteristic curves derived from the same cases. Radiology 148:839–843
Bland MJ, Altman DG (1986) Statistical methods for assessing agreement between two methods of clinical measurement. Lancet I:307–310
Tobin MJ, Perez W, Guenther S, Semmes BJ, Mador MJ, Allen SJ, Lodato RF, Dantzker DR (1986) The pattern of breathing during successful and unsuccessful trials of weaning from mechanical ventilation. Am Rev Respir Dis 134:1111–1118
Roussos C, Engel LA (1985) Thoraxlung interaction. In: Roussos C, Macklem PT (eds) The thorax. Dekker, New York, pp. 677–700
Weinger MB, Brimm JE (1987) End-tidal carbon dioxide as a measure of arterial carbon dioxide during intermittent mandatory ventilation. J Clin Monit 3:73–79
Smith RA, Novak RA, Venus B (1989) End-tidal CO2 monitoring utility during weaning from mechanical ventilation. Respir Care 34:972–975
Tobin MJ (1992) Breathing pattern analysis. Intensive Care Med 18:193–201
Rehder K, Marsch HM (1986) Respiratory mechanics during anesthesia and mechanical ventilation. In: Fishman, AP (ed) Handbook of physiology, Sect. 3. Respiration, vol. 3. American Physiological Society. Bethesda, pp. 737–752
Blanch LI, Fernandez R, Benito S, Mancebo J, Net A (1987) Effect of PEEP on the arterial minus end-tidal carbon dioxide gradient. Chest 92:451–454
Blanch LI, Fernandez R, Benito S, Mancebo J, Calaf N, Net A (1988) Accuracy of an indirect carbon dioxide Fick method in determination of the cardiac output in critically ill mechanically ventilated patients. Intensive Care Med 14:131–135
Nutter DO, Massumi RA (1966) The arterial-alveolar carbon dioxide tension gradient in diagnosis of pulmonary embolus. Chest 50:380–387
Yamanaka MK, Sue DY (1987) Comparison of arterial-end-tidal PCO2 difference and dead space/tidal volume ratio in respiratory failure. Chest 92:832–835
Lemaire F, Teboul JL, Cinotti JL, Giotto G, Abrouk F, Steg G, Macquin-Mavier I, Zapol WH (1988) Acute left ventricular dysfunction during unsuccessful weaning from mechanical ventilation. Anesthesiology 69:171–179
Jubran A, Tobin MJ (1994) Prédiction de l'issue du sevrage. In: Brochard L, Mancebo J (eds) Ventilation artificielle. Principes et applications. Arnette, Paris, pp 261–274
Author information
Authors and Affiliations
Additional information
Supported by grant 93/0590 from Fondo de Investigaciones Sanitarias de la Seguridad Social, Spain
Rights and permissions
About this article
Cite this article
Saura, P., Blanch, L., Lucangelo, U. et al. Use of capnography to detect hypercapnic episodes during weaning from mechanical ventilation. Intensive Care Med 22, 374–381 (1996). https://doi.org/10.1007/BF01712151
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF01712151