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Biomedical subjects

M A Sackner

Publications and source records attributed to M A Sackner.

At least 145 records · Page 8Linked to original sources
PubMed1975

Periodic sleep apnea: chronic sleep deprivation related to intermittent upper airway obstruction and central nervous system disturbance.

Periodic sleep apnea may be due to repeated episodes of upper airway obstruction in patients who have a short thick neck and/or large jowls. Apnea due to complete cessation of breathing may occur to a lesser extent. Anaylsis of the sleep electroencephalogram shows that these patients rarely achieve deep sleep and have less stage 1-REM sleep than normal subjects of comparable age. They are chronically sleep-deprived, a manifestation expressed by daytime somnolence, chronic fatigue and often by personality disturbances marked by paranoia, agitated depression and hostility. The definitive diagnosis of this syndrome may be established by monitoring during sleep, the electroencephalogram, measuring abdominal excursions through a mercury-in-Silastic-strain gauge and recording air flow at the nose by means of a thermocouple. As demonstrated by other investigators, chronic hypoventilation during sleep leads to both pulmonary and systemic arterial hypertension, which may produce generalized cardiac enlargement and congestive heart failure. The abnormalities in the periodic sleep apnea syndrome are abolished by establishing a patent airway either through tracheostomy or weight reduction.

Adult↗
PubMed1975

Effect of cuffed endotracheal tubes on tracheal mucous velocity.

The inflated cuffed endotracheal tube produces a significant depression of tracheal mucous velocity in anesthetized dogs after one hour. This effect occurs with bot low and high compliance cuffs but is not observed with an uncuffed tube. This phenomenon is another factor that must be considered in establishing criteria for the frequency of cuff deflation in patients supported by mechanical ventilators.

Animals↗
PubMed1974

Relationship between frequency dependence of lung compliance and distribution of ventilation.

The previously demonstrated empirical association between frequency dependence of lung compliance and distribution of ventilation, the latter determined by the N(2) washout technique, was confirmed by establishing a mathematical link between the two tests. By assuming a two-compartment system with known compliances and making corrections for Pendelluft and common dead space mixing effects, the ratio of dynamic to static compliance (C(dyn)/C(st)) for any respiratory frequency can be calculated from the compartmental analysis of the N(2) washout at a single respiratory frequency. By using these equations, a good correlation was found between calculated and measured C(dyn)/C(st) in dogs with artificially induced bronchial obstruction and in young smokers or young nonsmokers after carbachol inhalation. A two-compartment N(2) washout was demonstrated in 10 young healthy smokers at one or two respiratory frequencies whereas all 10 normal controls showed a single exponential curve. These findings indicate that the non-invasive N(2) washout test is capable of predicting C(dyn)/C(st) and at the same time gives a direct measure of gas distribution. Further, it appears to be a highly sensitive method for the detection of "small airway disease."

Adult↗
PubMed1973

Vertical distributions of pulmonary diffusing capacity and capillary blood flow in man.

In six normal upright subjects, a 100 mol bolus-composed of equal parts of neon, carbon monoxide, and acetylene (Ne, CO, and C(2)H(2))-was inspired from either residual volume (RV) or functional residual capacity (FRC) during a slow inspiration from RV to total lung capacity (TLC). After breath holding and subsequent collection of the exhalate, diffusing capacity and pulmonary capillary blood flow per liter of lung volume (D(L)/V(A) and Q(C)/V(A)) were calculated from the rates of CO and C(2)H(2) disappearances relative to Ne. The means: D(L)/V(A) = 5.26 ml/min x mm Hg per liter (bolus at RV), 6.54 ml/min x mm Hg per liter (at FRC); Q(C)/V(A) 0.537 liters/minute per liter (bolus at RV), 0.992 liters/minute per liter (at FRC). Similar maneuvers using Xenon-133 confirmed that, during inspiration, more of the bolus goes to the upper zone if introduced at RV and more to the lower, if at FRC. A lung model has been constructed which describes how D(L)/V(A) and Q(C)/V(A) must be distributed to satisfy the experimental data. According to this model, there is a steep gradient of Q(C)/V(A), increasing from apex to base, similar to that previously determined by other techniques-and also a gradient in the same direction, although not as steep, for D(L)/V(A). This more uniform distribution of D(L)/V(A) compared with Q(C)/V(A) indicates a vertical unevenness of diffusing capacity with respect to blood flow (D(L)/Q(C)). However, the relative degree of vertical unevenness of D(L)/V(A) compared with Q(C)/V(A) can account only in part for previous observations attributed to the inhomogeneity of D(L)/V(A) and Q(C)/V(A). Thus, a more generalized unevennes of these ratios must exist throughout the lung, independent of gravitation.

Acetylene↗