Abstract:Visual inspection for BWBP waveforms in real time can reliably identify stable breathing signals in client-owned cats. The obtained results were significantly different when the SVI method was used in addition to AE. In the interpretation of BWBP parameters or comparison of measurements among studies, whether an SVI methodology was applied should be considered.
“…Except for the parameter TV/BW, all other parameters changed significantly. In previous studies in cats, acclimatization times were not standardized or no information was given about the time cats spent in the measuring chamber before measurement started [ 4 – 6 , 22 , 26 – 28 ]. However, it is possible that in studies where the acclimatization time was not specified, it was individually adjusted to the behaviour of each cat to choose time periods for measurement, when animals seemed calm and relaxed.…”
Section: Discussionmentioning
confidence: 99%
“…However, this is usually not possible in clinical trials in companion animals. In different studies in cats the acclimatization time varied from 1–20 minutes [ 6 , 22 , 26 , 27 ] or no information was given at all [ 4 , 5 , 28 ]. In addition, it makes a difference for respiratory parameters whether cats are evaluated at home or in a hospital setting [ 29 , 30 ].…”
Background
Pulmonary function testing by barometric whole-body plethysmography (BWBP) is a long-established and well-accepted, non-invasive investigative procedure in cats.
Hypothesis/Objectives
To evaluate, if different acclimatization times influence the measurement parameters of BWBP in healthy adult cats.
Animals
48 healthy adult cats.
Methods
In the prospective observational study, healthy cats were placed in a measuring chamber and BWBP was performed over 30 minutes. Parameters obtained during the three measurement units of 10 minutes each (T1, T2 and T3) were compared.
Results
All measurement parameters except for tidal volume per body weight changed significantly (p<0.05) over the three time periods. From T1-T2, the parameters minute volume per body weight (p<0.001), peak inspiratory flow per body weight (p<0.001), peak expiratory flow per body weight (p = 0.002), pause (p = 0.03), enhanced pause (p = 0.03) and quotient of peak expiratory flow divided by expiratory flow at end expiratory volume plus 50% tidal volume (p = 0.03) changed significantly. From the time interval T2-T3, only respiratory rate (p = 0.02), inspiratory time (p = 0.02), expiratory time (p = 0.04), and relaxation time (p = 0.01) changed significantly. All measurement parameters except for tidal volume per body weight changed significantly (p<0.05) between T1 and T3. Age had a significant influence on all parameters except for peak expiratory flow per body weight and peak inspiratory flow per body weight. The parameters were not influenced by sex.
Conclusion and clinical importance
All measurement parameters except tidal volume per body weight were significantly affected by acclimatization time. Controlling for age and sex, there was still a significant influence of acclimatization time on all parameters except for tidal volume per body weight. Standardization of the acclimatization time for future studies would be appropriate in order to maintain comparability.
“…Except for the parameter TV/BW, all other parameters changed significantly. In previous studies in cats, acclimatization times were not standardized or no information was given about the time cats spent in the measuring chamber before measurement started [ 4 – 6 , 22 , 26 – 28 ]. However, it is possible that in studies where the acclimatization time was not specified, it was individually adjusted to the behaviour of each cat to choose time periods for measurement, when animals seemed calm and relaxed.…”
Section: Discussionmentioning
confidence: 99%
“…However, this is usually not possible in clinical trials in companion animals. In different studies in cats the acclimatization time varied from 1–20 minutes [ 6 , 22 , 26 , 27 ] or no information was given at all [ 4 , 5 , 28 ]. In addition, it makes a difference for respiratory parameters whether cats are evaluated at home or in a hospital setting [ 29 , 30 ].…”
Background
Pulmonary function testing by barometric whole-body plethysmography (BWBP) is a long-established and well-accepted, non-invasive investigative procedure in cats.
Hypothesis/Objectives
To evaluate, if different acclimatization times influence the measurement parameters of BWBP in healthy adult cats.
Animals
48 healthy adult cats.
Methods
In the prospective observational study, healthy cats were placed in a measuring chamber and BWBP was performed over 30 minutes. Parameters obtained during the three measurement units of 10 minutes each (T1, T2 and T3) were compared.
Results
All measurement parameters except for tidal volume per body weight changed significantly (p<0.05) over the three time periods. From T1-T2, the parameters minute volume per body weight (p<0.001), peak inspiratory flow per body weight (p<0.001), peak expiratory flow per body weight (p = 0.002), pause (p = 0.03), enhanced pause (p = 0.03) and quotient of peak expiratory flow divided by expiratory flow at end expiratory volume plus 50% tidal volume (p = 0.03) changed significantly. From the time interval T2-T3, only respiratory rate (p = 0.02), inspiratory time (p = 0.02), expiratory time (p = 0.04), and relaxation time (p = 0.01) changed significantly. All measurement parameters except for tidal volume per body weight changed significantly (p<0.05) between T1 and T3. Age had a significant influence on all parameters except for peak expiratory flow per body weight and peak inspiratory flow per body weight. The parameters were not influenced by sex.
Conclusion and clinical importance
All measurement parameters except tidal volume per body weight were significantly affected by acclimatization time. Controlling for age and sex, there was still a significant influence of acclimatization time on all parameters except for tidal volume per body weight. Standardization of the acclimatization time for future studies would be appropriate in order to maintain comparability.
“…The BWBP system was calibrated before each use by injecting 50 mL of air into the chamber, according to the manufacturer's instructions (Buxco Electronics, Wilmington, NC). The cat was placed in the BWBP chamber (length: 51 cm, width: 30 cm, and height: 25 cm) without any restraint, and an acclimation period (until the cat sat or laid down in a comfortable position with stable breathing signals) based on each cat's status was allowed before recording the signals, as previously described 14,19 . A bias flow of 6 L per minute was provided throughout the assessment to prevent carbon dioxide accumulation in the chamber, with temperature and humidity monitoring.…”
Section: Methodsmentioning
confidence: 99%
“…Conventional BWBP variables were calculated from breath‐by‐breath analysis of box flow waveforms by the software (Biosystem XA 2.11.0 software; Buxco Electronics), including RR (breaths/min), tidal volume per kg body weight (TV/BW; mL/kg), MV per kg BW (MV/BW; mL/kg; calculated by multiplying TV/BW by RR), inspiratory and expiratory times (Ti and Te; s), peak inspiratory and expiratory flow per kg BW (PIF/BW and PEF/BW; mL/s/BW), relaxation time (RT; s; time point when 65% of TV is expired), pause (unitless; [Te‐ RT]/RT), and enhanced pause (Penh; unitless; [PEF/PIF] × pause). Artifactual signals from nonbreathing activities (eg, posture change or vocalization) were excluded by applying both the automatic rejection settings of the software (TV < 10 mL, Ti < 0.15 s, Te > 10 s, or a difference in inspiratory and expiratory volume > 20%) and manual methodology (manually deleting time periods that were not free of artifacts based on simultaneous inspection) 19 . Considering that the nature of the pseudo‐volume differs from that of the true volume, the level of increase in MV was also expressed as a fold increase relative to the normal median value of the control group, with the aim of facilitating future applications in different systems.…”
Section: Methodsmentioning
confidence: 99%
“…14,19 A bias flow of 6 L per minute was provided throughout the assessment to prevent carbon dioxide accumulation in the chamber, with temperature and humidity monitoring. Analog breathing signals detected using a differential pressure transducer were amplified 19 Considering that the nature of the pseudo-volume differs from that of the true volume, the level of increase in MV was also expressed as a fold increase relative to the normal median value of the control group, with the aim of facilitating future applications in different systems.…”
BackgroundCats in respiratory distress have limited tolerance for manipulation, hindering clinical monitoring. Minute volume (MV) can be utilized to rate dyspnea in humans, but its relationship with respiratory distress in cats remains poorly investigated.HypothesisCats with respiratory distress will show higher MV per kg body weight (MV/BW) than normal cats, and the MV/BW increase will correlate with survival.AnimalsFifty‐two cats with respiratory distress from lung parenchymal disease, pleural space disease, lower airway obstruction (LAO), or upper airway obstruction were recruited since 2014.MethodsThis is a prospective observational study. Study cats were placed in a transparent chamber, allowing clinicians to easily observe their breathing status and record ventilation using barometric whole‐body plethysmography (BWBP). Ventilatory variables of the 52 cats were compared with those of 14 historic control cats. Follow‐up data, including disease category, clinical outcomes, and survival, were prospectively collected.ResultsCats in respiratory distress demonstrated significantly higher MV/BW (397 mL/kg; range, 158‐1240) than normal cats (269 mL/kg; range, 168‐389; P < .001). Among the etiologies, cats with LAO, parenchymal, and pleural space disease exhibited higher‐than‐normal MV/BW trends. A cutoff value of 373 mL/kg (1.4‐fold increase) indicated abnormally increased breathing efforts (sensitivity, 67%; specificity, 93%). MV/BW was independently associated with increased cardiorespiratory mortality in cats with respiratory distress (adjusted hazard ratio 1.17, 95% confidence interval [CI] 1.02‐1.35; P = .03).Conclusions and Clinical ImportanceBreathing efforts in cats can be noninvasively quantified using BWBP. Measurement of MV/BW could serve as a prognostic index for monitoring cats experiencing respiratory distress.
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