Preventive medicine and the Oklahoma City Veterans' Affairs Medical Center.

Beginning in 1996, the Oklahoma City VA Medical Center has implemented a preventive medicine program. This program includes such steps as tobacco and alcohol counseling, control of chronic illness and appropriate reminders and record-keeping. The results are promising.

A comparison of manual to mechanical chest percussion for clearance of alveolar material in patients with pulmonary alveolar proteinosis (phospholipidosis).

To our knowledge, there are no studies that compare the effectiveness of manual chest percussion (MN), mechanical chest percussion (MC), and no percussion (NP) for removing the proteinaceous material found in the alveoli of patients with pulmonary alveolar proteinosis (PAP) while undergoing whole-lung bronchopulmonary lavage (BPL). We analyzed the optical densities (OD) of 27 bottles of effluent from three BPLs of a patient with PAP. One technique was used per bottle. The order of techniques was balanced within each nine-bottle series and among the three BPLs. The mean OD for MN (0.933 +/- 0.494) was significantly superior to MC (0.477 +/- 0.265) (p < 0.0005) and NP (0.318 +/- 0.242) (p < 0.0001). We conclude that MN is superior to MC and NP and increases the therapeutic results of BPL for PAP.

Perceptions of VA chiefs of staff on total quality management implementation.

A national survey of United States Veterans Affairs (VA) Medical Centers (n = 167) chiefs of staff was conducted. The survey solicited feedback of the attitudes and perceptions of respondents toward planning, implementation, and monitoring of the Total Quality Management (TQM) process in their facilities. A Likert scale type of responses were collected and analyzed to measure the degree of agreement or disagreement of the respondents to survey statements on TQM. The survey included responses to three sections of the questionnaire: 25 statements on TQM, information on the TQM process status in the facility, and demographics of respondents and their facilities. The results of the survey indicate a considerable involvement of responding chiefs of staff in the TQM process and indicated their willingness to support it. Respondents agreed that TQM requires time and commitment of top management, and, again, they indicated their willingness to devote the time necessary for the process to succeed. They were, however, cautious in endorsing the statement that TQM will decrease health care costs (fiscal and human). The survey provides information that should prove valuable to administration in planning TQM and Continuous Quality Improvement efforts.

Cardiac arrhythmias during postural drainage and chest percussion of critically ill patients.

In this study we determine the prevalence and type of arrhythmias that occur during postural drainage and chest percussion (PDP) of critically ill patients, and identify those patients who are most at risk of developing them. We monitored the vital signs and ECGs of 72 ICU patients during their initial PDP treatment. Eight patients (11.1 percent) had development of major arrhythmias, 18 (25 percent) had minor arrhythmias, and 46 (63.9 percent) had none. Increased age (p < 0.0001) and the presence of acute cardiac disorders (p < 0.001) were associated with increased risk of arrhythmias. Individuals experiencing major arrhythmias had a significantly decreased BP and respiratory rate with an increased heart rate during PDP. We conclude that arrhythmias are common during PDP of critically ill patients and recommend that ICU patients be carefully monitored during PDP. When considering PDP for older patients and patients with acute cardiac disease, physicians should carefully weigh the risk of arrhythmias against the benefits of this treatment.

Effect of edema and hemodynamic changes on extravascular thermal volume of the lung.

The extravascular thermal volume of the lung (ETV) has been measured in dogs as the difference between mean transit time (t) volumes for heat and indocyanine green dye across the pulmonary circulation, calculated as the product of thermal dilution cardiac output (CO) and the difference in t for aortic indicator-dilution curves generated by right and left atrial injections. ETV measurements were compared with the extravascular lung mass (ELM): in 21 normal dogs, ETV/ELM = 1.11 +/- 0.14 (SD); in 17 dogs with hydrostatic pulmonary edema (up to 21 g/kg), ETV/ELM = 0.90 +/- 0.11; and in 27 dogs with alloxan pulmonary edema (up to 51 g/kg); ETV/ELM = 0.93 +/- 0.13. For all 65 dogs the mean ETVELM was 0.98 +/- 0.15, and the liner regression was ETV (ml/kg) = 0.90 ELM (g/kg) + 0.86 +/- 2.25 (SEE; r = 0.96). Calculations based on measurements of lung specific heat predict that ETV/ELM should equal 0.984. With acute changes in pulmonary hemodynamics, ETV was reduced by reductions in pulmonary arterial pressure (Ppa) sufficient to produce zone 1 conditions at the top of the lung. However, ETV was not affected by increases in CO (mean = 50%) produced by nitroprusside or by increases in Ppa and pulmonary blood volume (mean = 27%) produced by partial mitral valve obstruction. Distortion of the thermal dilution curve due to position of the arterial thermistor appears to be the greatest source of variability and overestimation. Simultaneous measurements from pairs of thermistors differed by 14% (range 0.4-50%).

In vitro labeling of the sialic acid moiety of glycoconjugates with carbon-14.

Labeling of sialoglycoproteins with carbon-14 in vitro was performed by reacting the aldehyde groups, generated by mild periodate oxidation of the terminal sialyl groups, with 14C-labeled sodium cyanide to produce the labeled cyanohydrin derivatives (Kiliani reaction). Labeling with tritium was carried out by reduction of the aldehyde groups generated on the sialyl residues with 3H-labeled sodium borohydride following standard procedures. The behavior of both types of labeled specimens of fetuin and ovine submaxillary mucin, individually and in mixtures, was investigated by gel-filtration chromatography, gel electrophoresis, and cesium bromide gradient ultracentrifugation. The labeled sialyl residues were subjected to partial characterization: color yield with the resorcinol and thiobarbituric acid reagents, behavior on ion-exchange chromatography, and susceptibility to mild acid and enzymatic hydrolyses. In addition to these model glycoproteins, this procedure was also utilized to label the sialoglycoproteins present in human tracheobronchial secretions collected from normal subjects and patients with chronic bronchitis. The potential uses of this approach for comparative studies of normal and pathological sialoglycoconjugates available in minute amounts is described. The extension of this approach to the labeling of the galactosyl and N-acetylgalactosaminyl moieties of glycoconjugates following treatment with galactose oxidase is outlined.

Effect of inspiratory flow rate on gas exchange during mechanical ventilation.

We studied the effect of changes in inspiratory flow rate (VI) on gas exchange and respiratory system mechanics during mechanical ventilation. Seven patients with respiratory failure caused by severe chronic airway obstruction (CAO group) and 6 patients with other causes of respiratory failure (ORF group) were studied at 3 VI settings, 40 L/min, 70 L/min, and 100 L/min. In the CAO group, as VI increased from 40 L/min to 100 L/min, arterial oxygen tension increased 18%, venous admixture decreased 23.2%, dead space to tidal volume ratio decreased 23.7%, and tidal compliance of the respiratory system increased 31.2%. In the ORF group, as VI increased, there was little change in most parameters measured. The changes in the CAO group may be explained by redistribution of ventilation to low ventilation-perfusion ratio units, which empty more completely during the longer expiratory times allowed at high VI. Using a simple two-compartment lung model we determined that an increase in expiratory time from 4.2 to 6.1 s (the increase observed in the CAO group as VI increased from 40 L/min to 100 L/min) will result in redistribution of ventilation to long expiratory time constant respiratory units and produce changes in lung mechanics and gas exchange similar to those observed experimentally. We concluded that mechanical ventilation at high VI in patients with CAO is associated with improvement in gas exchange and more even distribution of ventilation, which appear to be due to the increased time available for alveolar emptying.

Role of pulmonary edema in the acute pulmonary response to sepsis.

There is evidence that both bronchoconstriction and accumulation of lung water may contribute to the early alterations in lung function following septicemia. Eigher of these may be mediated by blood components. To assess these proposed mechanisms the changes in hemodynamics, pulmonary mechanics, gas exchange, and gravimetric lung water were measured in the first 4 h after Escherichia coli infusion in the anesthetized dog and baboon. These species were selected because of previously demonstrated differences in the response to gram-negative sepsis. Both species developed systemic hypotension and early hypoxemia. The dogs had early transient increases in venous admixture (Qva/Qt) but not shunt or dead space, while the baboon had a more persistent increase in Qva/Qt and a late increase in dead space, Increases in nonelastic resistance and decreases in lung compliance were preceded or accompanied by decreases in the leukocyte count in both species, but the platelet count, fibrinogen, and total hemolytic complement had different changes in the two species. Postmortem lung analysis revealed increased lung weight in both species but the wet weight-to-dry weight ratio was not increased in either species. The fractional water content of the excess lung mass was less than that of whole blood. Histological examination revealed large numbers of extravasated leukocytes in the lungs, which may be sufficient to explain the increase in lung weight. We conclude that pulmonary edema does not play a role in the early pulmonary response to E. coli bacteremia in either species. The physiological changes observed are more consistent with bronchoconstriction.

Effect of methysergide on the acute lung mechanics response to endotoxin.

The effect of the serotonin antagonist methysergide on the acute lung mechanics response to endotoxin in anesthetized, paralyzed, mechanically ventilated dogs was investigated. In five dogs given 0.25 mg/kg Escherichia coli endotoxin only, the pulmonary nonelastic resistance (RL) increased to 238% of control and dynamic compliance (CL) decreased to 50% of control. In a second group of five dogs, methysergide (0.25 mg/kg) was shown to markedly attenuate the lung mechanics response to serotonin (0.04 mg/kg), which alone had produced changes in lung mechanics greater than endotoxin. In these same dogs endotoxin administered after injection of methysergide produced an increase in RL to 377% and a decrease in CL to 33% of control. In a third group of five dogs whose lung mechanics response to serotonin was also greater than to endotoxin alone, endotoxin administered after injection of saline produced an increase in RL to 168% and a decrease in CL to 58% of control. Since the response to endotoxin after injection of methysergide exceeded the response after saline, we conclude that serotonin is not a mediator of the acute lung mechanics response to endotoxin.

Role of platelet serotonin in the canine pulmonary response to endotoxin.

There is evidence suggesting a role for platelet serotonin (5-HT) in the immediate pulmonary response to endotoxin in the dog (J. Appl. Physiol. 23: 47, 1967). To further define this role, autologous canine platelets were labeled with 5-[14C]HT in vitro and then reinfused. Subsequently Escherichia coli endotoxin (0.55:B-5, Difco), 2.5 mg/kg, was injected. Within 5 min dynamic compliance (CL) fell by more than 50%, and nonelastic resistance (RL) increased by more than 200%. Despite a 95% decrease in platelet count, less than 10% of the platelet 5-HT was released as determined by changes in the radioactivity of platelet-poor plasma (PPP) prepared from both aortic and pulmonary artery blood. As a positive control, injected of bovine collagen produced a similar decrease in platelet count that was associated with a significant increase in the radioactivity of aortic and pulmonary artery PPP. FInally, rapid injection of a dose of 5-HT equivalent to 25% of the 5-HT in circulating platelets did not cause a change in CL or RL equivalent to that produced by endotoxin. From these data we conclude that endotoxin injection does not cause immediate massive platelet activation and that platelet 5-HT does not play a major role in the immediate pulmonary response to endotoxin.

Effects on breathing of putative neurotransmitters in the rostral hypothalamus of the rat.

The putative neurotransmitters norepinephrine (NE) and thyrotropin releasing hormone (TRH) are normally present in the rostral hypothalamic region (RHT) of the rat, and our aim was to evaluate possible effects of these agents on ventilatory regulations associated with this region. Using haloperidol-tranquilized Sprague-Dawley rats, microinfusions of both NE and TRH into the RHT resulted in an increase in rate, but not depth, of breathing. Control infusions and control infusion sites, mainly in the posterior hypothalamus, yielded no significant effect on breathing rate. Since NE and TRH can inhibit the discharge of some cells in the RHT, it was possible that the observed effects on breathing were due to depression of an inhibitory neural pathway. This idea was further tested by performing microinfusions using lidocaine. Evidence suggests that lidocaine can inhibit discharge in the central nervous system and that inhibitory pathways may be preferentially affected. Lidocaine produced effects on breathing comparable to NE and TRH, thereby supporting the proposition that inhibition of neural pathways in the RHT can stimulate breathing.