Endotracheal temperature and humidity measurements in laryngectomized patients: intra- and inter-patient variability

Abstract

This study assesses intra-and inter-patient variability in endotracheal climate (temperature and humidity) and effects of heat and moister exchangers (HME) in 16 laryngectomized individuals, measured repeatedly (N = 47). Inhalation Breath Length (IBL) was 1.35 s without HME and 1.05 s with HME (P \ 0.0001). With HME, end-inspiratory (minimum) humidity values increased 5.8 mg H 2 O/L (P \ 0.0001) and minimum temperature values decreased 1.6°C (P \ 0.0001). For the temperature and humidity minimums, the inter-patient variability was much smaller than the short-and long-term intra-patient variability. For exhalation breath length and full breath length, the opposite was the case. Conclusions: (1) Because inter-patient variability is smaller than intrapatient variability, investigating endotracheal climate in a limited number of laryngectomized subjects is justified, provided repeated measurements per patient are accomplished; (2) main contributor to intra-patient variability is the positioning of the catheter tip in the trachea; (3) an HME leads to a shortened IBL which enhances the HME effect.

A New Heat And Moisture Exchanger for Laryngectomized Patients: Endotracheal Temperature and Humidity

“…We compared Provox Normal (which has well known heat and moisture exchanging capacity) [19][20][21] and Stomvent (an older model HME with a different design), to Rplus (which has a normal breathing resistance) and Lplus (which has a lower breathing resistance, comparable to that of the Provox HiFlow, which we did not test in this study). 20 We considered the Provox Normal the reference HME.…”

“…19 Each measurement session included five 7-min sampling periods, separated by 5-min rest breaks. One sampling period was with open stoma breathing (ie, without HME), and the other four were with the 4 studied HMEs: Provox Normal, Stomvent, Rplus, and Lplus.…”

“…3). 19 All measurements were performed in room climate conditions, which we monitored with a calibrated temperature and humidity sensor (Testo, Almere, The Netherlands).…”

“…Our data processing and analysis methods were described previously. 19 We analyzed the data from the last 2 min of each 7-min sampling period. The end-inhalation time points were identified with a peak-detection algorithm (Peaks Splus) in the statistics software (Splus 6.2 pro, Tibco, Somerville, Massachusetts).…”

“…The end-inhalation time points were identified with a peak-detection algorithm (Peaks Splus) in the statistics software (Splus 6.2 pro, Tibco, Somerville, Massachusetts). 19 We used the inhalation and exhalation midpoints to calculate the duration of the inspiratory phase, the expiratory phase, and the entire respiratory cycle (Fig. 4).…”