Biomedical subjects

A Böddener

Publications and source records attributed to A Böddener.

3 recordsLinked to original sources

PubMed1986

Immediate response to resistive loading in anesthetized humans.

In eight spontaneously breathing anesthetized subjects (halothane: approximately 1 minimal alveolar concn; 70% N2O-30% O2), we determined 1) the inspiratory driving pressure by analysis of the pressure developed at the airway opening (Poao) during inspiratory efforts against airways occluded at end expiration; 2) the active inspiratory impedance; and 3) the immediate (first loaded breath) response to added inspiratory resistive loads (delta R). Based on these data we made model predictions of the immediate tidal volume response to delta R. Such predictions closely fitted the experimental results. The present investigation indicates that 1) in halothane-anesthetized humans the shape of the Poao wave differs from that in anesthetized animals, 2) the immediate response to delta R is not associated with appreciable changes in intensity, shape, and timing of inspiratory neural drive but depends mainly on intrinsic (nonneural) mechanisms; 3) the flow-dependent resistance of endotracheal tubes must be taken into account in studies dealing with increased neuromuscular drive in intubated subjects; and 4) in anesthetized humans Poao reflects the driving pressure available to produce the breathing movements.

Adult↗

PubMed1986

Active and passive respiratory mechanics in anesthetized dogs.

In six spontaneously breathing anesthetized dogs (pentobarbital sodium, 30 mg/kg) airflow, volume, and tracheal and esophageal pressures were measured. The active and passive mechanical properties of the total respiratory system, lung, and chest wall were calculated. The average passive values of respiratory system, lung, and chest wall elastances amounted to, respectively, 50.1, 32.3, and 17.7 cmH2O X l-1. Resistive pressure-vs.-flow relationships for the relaxed respiratory system, lung, and chest wall were also determined; a linear relationship was found for the former (the total passive intrinsic resistance averaged 4.1 cmH2O X l-1 X s), whereas power functions best described the others: the pulmonary pressure-flow relationship exhibited an upward concavity, which for the chest wall presented an upward convexity. The average active elastance and resistance of the respiratory system were, respectively, 64.0 cmH2O X l-1 and 5.4 cmH2O X l-1 X s. The greater active impedance reflects pressure losses due to force-length and force-velocity properties of the inspiratory muscles and those due to distortion of the respiratory system from its relaxed configuration.

Anesthesia↗

PubMed1986

Respiratory and acid-base parameters during salicylic intoxication in dogs.

This paper examines the mechanism responsible for hyperventilation and accompanying respiratory alkalosis during acute salicylism. Sodium salicylate (250 mg/kg) was administered to 8 spontaneously breathing anesthetized dogs (alpha-chloralose, 50 mg/kg, and urethane, 500 mg/kg, iv). The trachea was sectioned and connected to a pneumotachograph. A catheter was placed in the cisterna magna for sampling cerebrospinal fluid (CSF) and a femoral artery was cannulated for blood sampling and pressure determinations. Once the cardiorespiratory steady-state was obtained, air flow, tidal volume, arterial pressure, ECG and rectal temperature were measured for baseline control. The measurements were repeated 8 times during 100 min after salicylate infusion. Simultaneous determinations of CSF and plasma salicylate showed that plasmatic levels were maximal just after infusion, diminishing with time. CSF concentration increased gradually as the salicylate diffused through the blood-brain barrier. Minute ventilation increased to more than 600% of control values and was maximal between 60-100 min after salicylate infusion. Respiratory alkalosis and hyperthermia (up to 40.3 degrees C) followed the time-course of hyperventilation. Only a small part of hyperventilation can be attributed to the temperature increase. A high correlation coefficient (r = 0.974) was obtained by regression analysis of the values for ventilation and CSF salicylate. We conclude that the central action of salicylate is much more important for increasing ventilation than effects related to oxidative phosphorylation uncoupling.

Alkalosis, Respiratory↗