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Carbon dioxide recruitment threshold as a predictor of successful weaning in chronic obstructive pulmonary disease patients: A pilot study
Author(s) -
KOH Abner T,
GUIA Teresita S,
ANG Evelyn T
Publication year - 1997
Publication title -
respirology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 85
eISSN - 1440-1843
pISSN - 1323-7799
DOI - 10.1111/j.1440-1843.1997.tb00072.x
Subject(s) - weaning , medicine , copd , pco2 , anesthesia , carbon dioxide , pulmonary disease , arterial blood , cardiology , ecology , biology
Several methods have been used to predict successful weaning and extubation among chronic obstructive pulmonary disease (COPD) patients. The objective of this study is to determine whether carbon dioxide recruitment threshold (PCO 2 RT) can be used as adjunct to conventional weaning parameters to predict early weaning and successful extubation. Twelve COPD patients who were ready to be extubated based on conventional weaning parameters were divided into group A ( n = 7) and group B ( n = 5). Group A were those patients with better weaning parameters and hence a higher probability of successful extubation as compared to group B. Carbon dioxide apnoeic threshold (PCO 2 AT) was obtained by hyperventilating the patient using an increment of two breaths per min until apnoea occurs. At this point, the PCO 2 AT or the PaCO 2 during said apnoeic period was recorded. A dead space of 150 cc is then added to the circuit until the patient starts to breathe as evidenced by the sensitivity trigger indicator. The PCO 2 obtained at this period is termed PCO 2 RT. After weaning for 30 min on a T‐tube, another arterial blood gas is determined and this is called the PCO 2 SB or the CO 2 level after 30 min on spontaneous breathing. If the PCO 2 SB‐PCO 2 RT difference is high with a sensitivity of 85.71% and specificity of 100% vs sensitivity of 57.14% and specificity of 60% using the conventional weaning parameters. Thus an increase in PCO 2 SB at 30 min T‐tube is indicative of impending respiratory pump failure and that other causes of failure to wean must be investigated.