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In order to limit the hemodilution effect during cardiopulmonary bypass (CPB) in low weight animal patients, blood is often used as a component of the prime solution. This study was undertaken to evaluate the effects of the addition of blood to the prime solution on the hemodynamic and respiratory parameters during and following mitral valve replacement in dogs. Ten dogs were randomly assigned to receive either a hemic (HP), 75% blood component, or a nonhemic prime (NP) solution. The hemodilution was 5 +/- 4% and 25 +/- 10% for the HP and NP groups, respectively. Cardiopulmonary measurements were taken 20 minutes before initiating CPB, during CPB, and 20 min after termination. The hematocrit level, the hemoglobin concentration, and the arterial oxygen content were significantly lower in the NP group during and following CPB. However, the systemic oxygen transport index was not significantly different between the NP group (355 +/- 87 mL/min/m2) and the HP group (546 +/- 155 mL/min/m2) following CPB. Our study indicates that, in normal dogs undergoing hemodilution from a nonhemic prime solution, the cardiovascular function is able to maintain the systemic oxygen transport in the period immediately following mitral valve replacement., Afin de limiter l'hémodilution pendant la circulation extracorporelle (CPB) chez les animaux de faible poids, du sang peut être ajouté dans la solution d’amorçage. L'objectif de cette étude consistait à évaluer les effets de l'ajout de sang dans la solution d’amorçage sur les paramètres hémodynamiques et respiratoires pendant et après la réalisation d'un remplacement valvulaire mitral chez le chien. Chez 10 chiens subissant un remplacement valvulaire mitral, le circuit extracorporel était amorcé de façon aléatoire soit avec une solution contenant 75 % de sang (HP) soit avec une solution cristalloïde dépourvue de sang (NP). L'hémodilution résultante était respectivement de 5 ± 4 % et de 25 ± 10 % pour les groupes HP et NP. Les mesures cardiorespiratoires étaient effectuées 20 minutes avant l’établissement de la CPB, pendant la CPB et 20 minutes après l’arrêt de la CPB. L'hématocrite, la concentration en hémoglobine et le contenu en oxygène du sang artériel était significativement plus bas dans le groupe NP que dans le groupe HP pendant et après la CPB. Cependant, l'index du transport systémique d’oxygène n’était pas significativement différent entre le groupe NP (355 ± 87 mL/min/m2) et le groupe HP (546 ± 155 mL/min/m2) après la CPB. Notre étude indique que la fonction cardiovasculaire est capable de maintenir le transport systémique d’oxygène immédiatement après un remplacement valvulaire mitral chez des chiens normaux malgré l'hémodilution associée a un amorçage dépourvu de sang.

The optimal duration of the time-window used to compute the time-frequency representation (spectrogram) of the phonocardiogram was studied in four dogs by using intracardiac and thoracic measurements of the PCG. The power and cross-spectrograms of the intracardiac and thoracic PCGs were computed using a fast Fourier transform algorithm and a sine-cosine window with 10 per cent decaying functions. A coherence spectrogram was also computed for each dog to study the linear relationship between the two signals and determine the optimal time-window duration. Results show that the optimal range of the time-window duration is between 16 and 32 ms. A time-window shorter than 16ms spreads out low-frequency components into the higher frequencies and generates a spectrographic representation with poor frequency resolution (=62·5 Hz). A window larger than 32 ms increases the frequency resolution but smears the spectrographic representation of the signal in the time domain and thus cannot correctly reflect the time-varying properties of the signal. In both cases, the amplitude of the coherence function computed between the left ventricular and the thoracic phonocardiograms is overestimated.

In order to limit the hemodilution effect during cardiopulmonary bypass (CPB) in low weight animal patients, blood is often used as a component of the prime solution. This study was undertaken to evaluate the effects of the addition of blood to the prime solution on the hemodynamic and respiratory parameters during and following mitral valve replacement in dogs. Ten dogs were randomly assigned to receive either a hemic (HP), 75% blood component, or a nonhemic prime (NP) solution. The hemodilution was 5 +/- 4% and 25 +/- 10% for the HP and NP groups, respectively. Cardiopulmonary measurements were taken 20 minutes before initiating CPB, during CPB, and 20 min after termination. The hematocrit level, the hemoglobin concentration, and the arterial oxygen content were significantly lower in the NP group during and following CPB. However, the systemic oxygen transport index was not significantly different between the NP group (355 +/- 87 mL/min/m2) and the HP group (546 +/- 155 mL/min/m2) following CPB. Our study indicates that, in normal dogs undergoing hemodilution from a nonhemic prime solution, the cardiovascular function is able to maintain the systemic oxygen transport in the period immediately following mitral valve replacement., Afin de limiter l'hémodilution pendant la circulation extracorporelle (CPB) chez les animaux de faible poids, du sang peut être ajouté dans la solution d’amorçage. L'objectif de cette étude consistait à évaluer les effets de l'ajout de sang dans la solution d’amorçage sur les paramètres hémodynamiques et respiratoires pendant et après la réalisation d'un remplacement valvulaire mitral chez le chien. Chez 10 chiens subissant un remplacement valvulaire mitral, le circuit extracorporel était amorcé de façon aléatoire soit avec une solution contenant 75 % de sang (HP) soit avec une solution cristalloïde dépourvue de sang (NP). L'hémodilution résultante était respectivement de 5 ± 4 % et de 25 ± 10 % pour les groupes HP et NP. Les mesures cardiorespiratoires étaient effectuées 20 minutes avant l’établissement de la CPB, pendant la CPB et 20 minutes après l’arrêt de la CPB. L'hématocrite, la concentration en hémoglobine et le contenu en oxygène du sang artériel était significativement plus bas dans le groupe NP que dans le groupe HP pendant et après la CPB. Cependant, l'index du transport systémique d’oxygène n’était pas significativement différent entre le groupe NP (355 ± 87 mL/min/m2) et le groupe HP (546 ± 155 mL/min/m2) après la CPB. Notre étude indique que la fonction cardiovasculaire est capable de maintenir le transport systémique d’oxygène immédiatement après un remplacement valvulaire mitral chez des chiens normaux malgré l'hémodilution associée a un amorçage dépourvu de sang.

The optimal duration of the time-window used to compute the time-frequency representation (spectrogram) of the phonocardiogram was studied in four dogs by using intracardiac and thoracic measurements of the PCG. The power and cross-spectrograms of the intracardiac and thoracic PCGs were computed using a fast Fourier transform algorithm and a sine-cosine window with 10 per cent decaying functions. A coherence spectrogram was also computed for each dog to study the linear relationship between the two signals and determine the optimal time-window duration. Results show that the optimal range of the time-window duration is between 16 and 32 ms. A time-window shorter than 16ms spreads out low-frequency components into the higher frequencies and generates a spectrographic representation with poor frequency resolution (=62·5 Hz). A window larger than 32 ms increases the frequency resolution but smears the spectrographic representation of the signal in the time domain and thus cannot correctly reflect the time-varying properties of the signal. In both cases, the amplitude of the coherence function computed between the left ventricular and the thoracic phonocardiograms is overestimated.