Hot-wire anemometer for spirography

Plakk, P.; Liik, P.; Kingisepp, Peet-Henn

doi:10.1007/bf02522852

Cited by 23 publications

(16 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A hot wire anemometer (Florian: Acutronic Medical Systems AG, Zug, Switzerland) was attached proximally to the Laerdal mask measuring inspiratory and expiratory gas flow (see also Fig. 1) (25). The flow signal was integrated to provide inspired and expired tidal volume.…”

Section: Methodsmentioning

confidence: 99%

Breathing Patterns in Preterm and Term Infants Immediately After Birth

et al. 2009

View full text Add to dashboard Cite

There is limited data describing how preterm and term infants breathe spontaneously immediately after birth. We studied spontaneously breathing infants Ն29 wk immediately after birth. Airway flow and tidal volume were measured for 90 s using a hot wire anemometer attached to a facemask. Twelve preterm and 13 term infants had recordings suitable for analysis. The median (interquartile range) proportion of expiratory braking was very high in both groups (preterm 90 ͓74 -99͔ vs. term 87 ͓74 -94͔%; NS). Crying pattern was the predominant breathing pattern for both groups (62 ͓36 -77͔% vs. 64 ͓46 -79͔%; NS). Preterm infants showed a higher incidence of expiratory hold pattern (9 ͓4 -17͔% vs. 2 ͓0 -6͔%; p ϭ 0.02). Both groups had large tidal volumes (6.7 ͓3.9͔ vs. 6.5 ͓4.1͔ mL/kg), high peak inspiratory flows (5.7 ͓3.8͔ vs. 8.0 ͓5͔ L/min), lower peak expiratory flow (3.6 ͓2.4͔ vs. 4.8 ͓3.2͔ L/min), short inspiration time (0.31 ͓0.13͔ vs. 0.32 ͓0.16͔ s) and long expiration time (0.93 ͓0.64͔ vs. 1.14 ͓0.86͔ s). Directly after birth, both preterm and term infants frequently brake their expiration, mostly by crying. Preterm infants use significantly more expiratory breath holds to defend their lung volume. (Pediatr Res 65: 352-356, 2009)

show abstract

Section: Methodsmentioning

confidence: 99%

Breathing Patterns in Preterm and Term Infants Immediately After Birth

et al. 2009

View full text Add to dashboard Cite

show abstract

“…Hopefully, in the near future, precise¯owmeters with negligible¯ow resistance (e.g. anemometers [35] or ultrasonic sensors [36]) will become routinely available, so that, in addition to the elimination of apparatus dead space by the FTT, the resistive load can also minimized.…”

Section: Discussionmentioning

confidence: 99%

Effect of apparatus dead space on breathing parameters in newborns: “flow-through”versusconventional techniques

et al. 2001

View full text Add to dashboard Cite

Commercial devices for tidal breathing measurements in newborns allow only short-term measurements, due to the high apparatus dead space of the face mask and pneumotachometer. The¯ow-through technique (FTT) minimizes the dead space by a background¯ow, thereby allowing long-term measurements. The aim of this study was to investigate the comparability of tidal breathing parameters using both techniques.Paired measurements of tidal breathing were performed in 86 sleeping infants (median (range) body weight 2.8 kg (1.9±5.3 kg), age 65 days (3±150 days)), using the FTT and SensorMedics 2600 (SM 2600).There was a signi®cant bias (pv0.001) in all tidal breathing parameters. Compared with the FTT, increases (95% con®dence interval (CI)) in tidal volume (VT), respiratory frequency (fR), and minute ventilation (V'E) were 0.74 (0.5±1.0) mL . kg -1 , 9.0 (6.9±11.2) . min -1 and 92 (74±109) mL . min -1 . kg -1 when measured with the SM 2600, representing average increases of 13, 17 and 30%, respectively, in response to the added dead space. By contrast, time to peak tidal expiratory¯ow as a proportion of expiratory time (tPTEF/tE) was changed by -0.09 (-0.11±-0.08). The mean (95% CI) change in tPTEF/tE of -54 (-62±-45)%, when measured in infants by the SM 2600, was remarkably similar to that observed during in vitro validation studies (-59 (-73±-44)%), suggesting that the discrepancies in timing parameters may be largely attributable to differences in signal processing.In conclusion, differences in measurement technique and precision of the devices used can result in signi®cant differences in tidal breathing parameters. This may impede the comparison of results within and between infants and the clinical interpretation of tidal breathing measurements in newborns. Eur Respir J 2001; 17: 108±114.

show abstract

“…For spirography applications, in order to avoid the barometric pressure, the value of air density, q, should be considered in Eq. (3). Constants A, B…”

Section: Theoretical Background and Operating Circuitmentioning

confidence: 98%

“…Various flow measurement methods can be mentioned as differential (pressure difference), linear (turbine, vortex shedding) and nonlinear (hot-wire/hot-film). Each method has its own merits and demerits [3].…”

Section: Introductionmentioning

confidence: 99%