Rehabilitacija - Letnik VII. rnp/. -1 ( 2008/ 
SYMPTOMS OF RESP/RATORY 
FUNCTION INSUFFICIENCY AND 
ARTERIAL BLOOD GASES ANALYSIS 
AS PROGNOST/C INDICATORS IN ALS 
L. Leonardis, L. Dolenc-Grošelj, J. Zidar
Institute of Clinical Neurophy siology, University Medica! Ce ntre Ljubljana, Ljubljana, Slovenia
INTRODUCTION 
Many patients with amy otrophic lateral sclerosis (ALS) 
develop symptoms of respiratory insufficiency during the 
time of the disease and for the majority respiratory failure is 
the cause of the death ( 1 ). We were interested in usefulness 
of symptoms of respiratory insufficiency and/or abnormal 
results of the daytime arterial gas analyses as indicators 
(AGA) for initiation of non-invasive mechanical ventilation 
(NIV) and if they are predictive for survival. 
METHODS 
Clinical and laboratory data of 82 patients with ALS, 
who were followed by our ALS clinic since October 2002 
and died before July 2008, were analyzed retrospectively. 
Patients were regularly followed at 3-month intervals. 
We questioned them about the symptoms of respiratory 
insufficiency (dyspnoea. orthopnoea, morning headaches, 
nightmares, disturbed sleep), and performed arterial gases 
analyses. The last AGA was on average performed 65 days 
before death (range: 1- 702 days, SO 130). Patients with 
respiratory infections or lung disease were cxcluded f
r
om 
study . 
RESULTS 
Mean age at the disease onset was on average 70 years (SO 
11 ). Fifty-three patients reported symptoms of respiratory 
insufficiency which started 23 months after the disease onset 
(range 0-108 months, SO 22) and died on average 9 months 
later (SO 9). These patients had slightly longer survival (29 
months from the disease onsct (SO 21 )) compared to those 
without respiratory problems (mean 25 months, SO 14), but 
the difference was not significant (t = 0.89, p = 0.38). Thir-
lil 
teen symptomatic patients and/or those with increased p 
co2
saturation underwent a NIV llial but only seven of them used 
it for at least 4 hours per night (good compliance). They, on 
average, survived for 31 2 days (range 52-485 days, SO 150) 
after the onset of respiratory insufficiency. Those who did 
not comply with NIV, survived for 258 days (range 3-1347, 
SO 279). The difference was not significant (t = 0.50, p = 
0.62). At least two arterial gas analyses were performed in 48 
patients. Only 48%, 67% and 27% of patients had abnormal 
Pco
2
, p
02 
and oxygen saturation, respectively, at any tirne of 
the disease course. Symptoms of respiratory insufficiency 
most commonly preceded AGA abnormalities and much 
less frequently occurred concurrcntly or afterwards. AGA 
abnonnalities could even not be detected at ali. First abnor­
malities in Pcm' p
02 
and oxygen saturation were found 160, 
297 and 108 days before death, respectively. NIV tolerant 
and intolerant patients had similar survival ( 143 compared to 
150 days on average) when measured f
r
om the first abnormal 
Pcm result. Similar 11011-significant differences were found 
also, when low p
02 
values and oxygen desaturation were 
used as starting point of survival measurements. Mean age 
at the discase onset was at 70 years (SO 11 ). 
CONCLUSION 
In our small group of paticnts, the occurrence of symptoms 
of respiratory i nsufficiency and arterial gases abnormal ities 
did not aflect survival and are thercforc unlikely to be useful 
as only indicators for NIV initiation. 
Referenc e: 
l. Borasio GO, Gelinas OF, Yanagisawa N. Mechanical ven­
tilation in amyotrophic laterni sclerosis: a cross-cultural
perspective. J Neurol 1998; 245 (Suppl 2): 7-12.