by Pornpan Rattanajiajaroen and Napplika Kongpolprom
Critical Care volume 25,
Article number: 365 (2021)
Background
Timing of swallows in relation to respiratory phases is
associated with aspiration events. Oxygen therapy possibly affects the timing
of swallows, which may alter airway protective mechanisms.
Objectives
To compare the coordination between swallowing and
respiration during water infusion in post-extubation patients using high flow
nasal oxygen (HFNO) with the coordination in those using low flow nasal oxygen
(LFNO).
Methods
We conducted a randomized controlled crossover study in
post-extubation patients. The patients extubated within 48 h were randomly
assigned to two groups, namely, HFNO and LFNO. The eligible patients in each
group received either HFNO with fraction of inspired oxygen (FiO2) 0.35, flow
50 L per minute (LPM), and temperature 34 °C or LFNO 5 LPM for 5 min.
The coordination between swallowing and respiration was observed during
continuous infusion of 10-ml water one minute three times. Respiratory phases
and swallowing were monitored using electrocardiogram (EKG)-derived respiratory
signals and submental electromyography (EMG), respectively. The swallowing
frequency and timing of swallows in relation to respiratory phases were
recorded. The coordination between swallowing and respiration was classified
into 4 patterns, namely I, E, I-E, and E-I swallows. (I; inspiration and E;
expiration) Subsequently, after a 5-min washout period, the patients were
switched to the other type of oxygen therapy using the same procedure. The
Wilcoxon Signed-Rank Test was used for statistical analysis.
Results
A total of 22 patients with a mean age of 56 years were
enrolled in the study. The major indication for invasive mechanical ventilation
was pneumonia with a median duration of endotracheal intubation of
2.5 days. The median total swallowing numbers (three minutes) were 18.5
times in the HFNO period and 21 times in the LFNO period (p = NS). The most
common swallowing pattern was E-swallow. The patients using HFNO had higher
numbers of E-swallow pattern (74.3% in HFNO vs 67.6% in LFNO; p = 0.048)
and lower numbers of I-swallow pattern (14.3% in HFNO vs 23.1% in LFNO; p = 0.044).
The numbers of other swallowing patterns were not different between the 2
groups.
Conclusions
Compared with LFNO, HFNO significantly increased the
E-swallow and decreased the I-swallow in post-extubation patients. The findings
indicated that HFNO might reduce a risk of aspiration during the
post-extubation period.
