Horsley, Alex; Siddiqui, Salman
Respirology, January 2015, Vol. 20 Issue: Number 1 p33-45, 13p
Abstract: Adult cystic fibrosis (CF) is notable for the wide heterogeneity in severity
of disease expression, both between patients and within the lungs of
individuals. Although CFairways disease appears to start in the small
airways, in adults there is typically widespread bronchiectasis,
increased airway secretions, and extensive obstruction and inflammation
of the small airways. The complexity and heterogeneity of airways
disease in CFmeans that although there are many different methods of
assessing and describing lung ‘function’, none of these
single‐dimensional tests is able to provide a comprehensive assessment
of lung physiology across the spectrum seen in adult CF. The most
widely described measure, the forced expiratory volume in 1 s, remains
a useful and simple clinical tool, but is insensitive to early changes
and may be dissociated from other more detailed assessments of disease
severity such as computed tomography. In this review, we also discuss
the use of more sensitive novel assessments such as multiple breath
washout tests and impulse oscillometry, as well as the role of
cardiopulmonary exercise testing. In the future, hyperpolarized gas
magnetic resonance imaging techniques that combine regional structural
and functional information may help us to better understand these
measures, their applications and limitations.;

Ninaber, M.K.; Hamersma,
W.B.G.J.; Schouffoer, A.A.; van ’t Wout, E.F.A.; Stolk, J.. QJM:

An International Journal of Medicine, January 2015, Vol. 108 Issue: Number
1 p33-33, 1p;

Abstract:

Background: Exercise intolerance (EI) in
systemic sclerosis (SSc) is difficult to manage by the clinician. The
peripheral chemoreflex drive compensates for metabolic acidosis during
exercise and may be related to EI. Aim: To assess the global peripheral
chemoreflex drive (GPCD) in patients with SSc at rest and during
exercise.

Methods: Consecutively tested SSc patients (n = 49) were
evaluated by pulmonary function tests, carbon dioxide (CO2)
rebreathing studies and non-invasive cardiopulmonary exercise testing
(CPET). Results of their CO2 rebreathing tests were compared
with those of controls (n = 32). Respiratory compensation for
metabolic acidosis during CPET was defined by the occurrence of a sharp
increase in minute ventilation (VdotE) and the ventilatory equivalent
for CO2 (V’E and V’CO2) at the end of the
isocapnic buffer phase. Euoxic (eVHR) and hyperoxic (hVHR) ventilatory
responses to hypercapnia were measured and its difference (eVHR − hVHR)
was considered to reflect the GPCD. Results: In 45 patients with SSc,
CPET results showed respiratory compensation at the occurrence of
metabolic acidosis. eVHR − hVHR in patients with diffuse cutaneous SSc
(dcSSc) differed significantly from that in patients with limited
cutaneous SSc (lcSSc) and from that in controls (0.47 ± 0.38 (dcSSc)
vs. 0.90 ± 0.77 (lcSSc) and 0.90 ± 0.49 (controls) l/min/mmHg; P =
0.04 and P = 0.03, respectively).

Conclusions: Respiratory
compensation for metabolic acidosis occurred in all patients. However,
the GPCD was diminished in dcSSc patients, suggesting an altered
control of breathing. Its assessment may help the clinician to better
understand reported EI and exertional dyspnea in dcSSc patients.;