A quick and easy method of measuring the hypercapnic ventilatory response in patients with COPD

Abstract

In COPD patients non-steady-state HCVR using PetCO(2) is well tolerated, which is as accurate as PaCO(2). HCVR slope may be derived using PetCO(2) during steady-state testing, though there may be errors in intercept compared to use of PaCO(2). In healthy volunteers PetCO(2) may be used to estimate PaCO(2) during steady-state but not rebreathing HCVR.

The effect of metabolic alkalosis on the ventilatory response in healthy subjects

“…The commonly used clinical endpoint of the HCVR test, the ratio between the maximal V E in respect to its baseline value (ΔV E ) and the maximal P et CO 2 in respect to its baseline value (ΔP et CO 2 ), was calculated (Nickol et al, 2009).…”

“…The chemosensitivity influences regulation of V E and the response of various physiological and pathophysiological states to V E (Oren et al, 1991). There are various protocols to test the hypercapnic ventilatory response, all aiming at measuring the increase in V E by increasing P insp CO 2 (American Thoracic Society/European Respiratory Society, 2002;Nickol et al, 2009;Oren et al, 1991). This study used an adapted version of these protocols, and succeeded in changing V E and P et CO 2 as a result of increased P insp CO 2 .…”

“…A multielectrode esophageal catheter with two balloons (NeuroVent Research Inc, Toronto, Canada) was inserted and positioned, as described previously (Doorduin et al, 2012). The ventilatory response to inhaled CO 2 was assessed by a HCVR test (Nickol et al, 2009;Oren et al, 1991); subjects were seated in upright position with uncast abdomen and wearing a nose clip, breathing through a mouthpiece. First, subjects were breathing ambient air via a one-way valve from a reservoir breathing bag, which was continuously filled with ambient air.…”

“…The slow adaptation of bicarbonate remaining in the blood may result in posthypercapnic alkalosis (Banga and Khilnani, 2009). This alkalosis may cause a reduced ventilatory response to hypercapnia in patients with moderate to severe chronic obstructive pulmonary disease (COPD), as demonstrated by a decreased response in minute ventilation (V E ) for a given change in end-tidal carbon dioxide (P et CO 2 ) (Nickol et al, 2009). However, Oren and colleagues showed that chronic metabolic acid-base changes do not alter the hypercapnic ventilatory response (HCVR) in 4 healthy subjects (Oren et al, 1991).…”

Application of Non-invasive Positive Pressure Ventilation Combined with PetCO₂ Monitoring for Patients with Chronic Obstructive Pulmonary Disease Combined with Severe Respiratory Failure

“…With mainstream type PetCO2 monitoring, as a non-invasive monitoring technology, it can continuously and non-invasive monitor the pressure or concentration of carbon dioxide in human alveolar. 14 This makes it a very critical respiratory care indicator. This has commonly been used for monitoring patients in anesthesia care, pre-hospital emergency care and tracheal intubation.…”