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A B Adams

Publications and source records attributed to A B Adams.

8 recordsLinked to original sources
PubMed1992

Lung mechanics and gas exchange during pressure-control ventilation in dogs. Augmentation of CO2 elimination by an intratracheal catheter.

Increased awareness of pressure-related injury to the alveolar-capillary interface has renewed interest in modes of ventilation that limit alveolar distention such as pressure-controlled ventilation (PCV). We examined respiratory system mechanics and gas exchange during PCV in six dogs. Our data conformed to the predictions of our single-compartment mathematical model of respiratory dynamics during PCV (J Appl Physiol 1989; 67:1081-92). For a fixed pressure (Pset) and inspiratory time fraction (Tl/Ttot) (15 cm H2O and 0.3, respectively), minute ventilation (VE) reached a well-defined plateau as frequency (f) increased from 10 to 50 breaths/min and tidal volume (VT) fell progressively. Concomitantly, the physiologic dead-space fraction (VD/VT) increased from 0.50 +/- 0.04 to 0.85 +/- 0.04, and arterial PCO2 (PaCO2) rose from 39 +/- 4 to 76 +/- 12 mm Hg. At a fixed combination of frequency, applied pressure, and Tl/Ttot (40 breaths/min, 15 cm H2O, and 0.3), VE did not change when we introduced fresh gas continuously from an intratracheal catheter. However, PaCO2 and VD/VT fell progressively as catheter flow increased from zero to 14 L/min (60 +/- 12 to 40 +/- 12 mm Hg and 0.83 +/- 0.03 to 0.25 +/- 0.14 mm Hg, respectively). We conclude that during PCV at a fixed Pset and Tl/Ttot increasing frequency caused VT to fall and VE to reach a plateau. Declining VT was associated with a rise in PaCO2 because of a subsequent fall in alveolar ventilation. Insufflating fresh gas by an intratracheal catheter increased alveolar ventilation and improved CO2 elimination by washing out the anatomic dead space.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Tracheal gas insufflation during pressure-control ventilation. Effect of catheter position, diameter, and flow rate.

In the setting of acute lung injury, ventilatory strategies that adjust minute ventilation (VE) to achieve eucapnia often lead to alveolar rupture or damage. Tracheal gas insufflation (TGI) reduces the VE requirements of conventional mechanical ventilation by decreasing the effective dead-space fraction (VD/VT) of each breath. We studied the effect of catheter flow rate (Vcath) and position as well as catheter tip diameter and configuration on CO2 elimination during TGI-augmented pressure-controlled ventilation (PCV) in normal dogs. We studied three catheter positions (1, 5, and 10 cm above the carina) at Vcath of 2, 5, and 10 L/min (n = 6). When the catheter tip was positioned 1 cm above the carina, PaCO2 decreased significantly from a baseline (PCV alone) of 67 +/- 10 mm Hg to 52 +/- 11, 43 +/- 9, and 32 +/- 7 mm Hg (p < 0.05) at Vcath of 2, 5, and 10 L/min, respectively. For the same Vcath values, positioning the catheter tip 10 cm above the carina increased PaCO2 to 54 +/- 15, 46 +/- 12, and 40 +/- 11 mm Hg. Advancing the catheter tip 2 cm below the carina did not improve PaCO2 significantly (n = 3). At a catheter position of 1 cm above the carina and a Vcath of 10 L/min, changing the luminal inner diameter (1.5 versus 3.0 mm) or tip configuration (open tip versus occluded tip with two side holes) of the catheter did not change PaCO2.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1976

The basic science curriculun problem in dental education: some causes and solutions.

At present there is no established purpose generally agreed on by members of the dental profession for the basic sciences in the dental curriculum. Such a purpose, supported by the entire profession, is considered a necessary first step in improving the basic science curriculum. Substantive basic science courses should be taught by instructors, holding a Ph.D. degree. These basic science instructructors, however, need the respect of the clinical faculty in order to be effective in teaching dental students. They also need to be given professional opportunity equal to that given clinical faculty if they are to commit themselves to dental education. The role of the clinical faculty in teaching the scientific basis of clinical methods is described, and the need for cooperation and communication between the basic science and clinical faculties is emphasized. Regularly scheduled faculty workshops are recommended for this purpose. A decrease in student contact time for clinical faculty is also suggested. The dental profession, led by dental educators, with advice from other health professionals, dental students, and the general public, is the logical body to define the purpose of basic science in dental education.

Curriculum↗