Self-report of delivery of clinical preventive services by U.S. physicians. Comparing specialty, gender, age, setting of practice, and area of practice.

OBJECTIVES: To summarize national survey results for key clinical preventive services provided by primary care physicians, characterize the results by demographic and practice attributes of the respondents, and compare the results to those obtained in other studies. DESIGN: Cross-sectional study. PARTICIPANTS: A total of 3881 clinicians who provided primary care at least 50% of their time, randomly sampled from the professional associations representing family practitioners, pediatricians, internists, and OB-GYNs. MEASURES: The Primary Care Providers Survey instrument of 1992, administered through the Office of Disease Prevention and Health Promotion, designed to assess the provision of clinical preventive services by primary caregivers. MAIN RESULTS: Few of the physicians surveyed reported providing most indicated clinical preventive services more than 80% of the time. For the purposes of this paper, > 80% provision of preventive services is considered adequate. Female physicians reported providing more preventive services involving exercise, diet, alcohol/drugs, seatbelts, sexual activity, family planning, immunizations, and screening procedures. Physicians aged < 50 reported providing more preventive services involving smoking, alcohol/drugs, seatbelts, sexual activity, and family planning. Older physicians generally reported more delivery of vaccines and screening procedures. Practitioners from big metropolitan areas reported more preventive services involving alcohol/drugs and family planning while respondents in rural areas reported less immunizations and screening procedures. When analyzed by specialty, physicians reporting the most preventive care varied by type of preventive care. CONCLUSIONS: Small differences in the self-report of provision of clinical preventive services between specialties and demographic subgroups did exist. At the time of this survey, however, no group of primary care physicians reported providing clinical preventive services to their patients at adequate levels.

Physician office-based diabetes care: comparison to guidelines for care.

Over the past decade, we have seen a significant increase in hospitalizations in South Carolina for the major complications of diabetes: myocardial infarcts (+68 percent), amputations (+61 percent), end stage renal disease (+85 percent), diseases of blood vessels (+100 percent), and eye complications (+52 percent). Many of these late stage complications can be prevented or their progression slowed down by early recognition and institution of intensive, well-defined preventive strategies. Independent surveys reviewed above indicate that such preventive practices are not being fully utilized in South Carolina. As one key example, less than 50 percent of people with diabetes receive self-management education. A number of simple and relatively inexpensive laboratory and physical examinations which would trigger preventive and remedial therapy are also performed at less than adequate frequency. The challenge is for all to use these examinations to guide therapy and to continue to monitor and intervene to prevent complications of diabetes. The DSC Board of South Carolina has developed a Ten Year Strategic Plan with nine major goals to improve diabetes care and outcomes in South Carolina. To improve office-based care of diabetes in South Carolina, all health professionals must assume responsibility for closely monitoring each person with diagnosed diabetes and assure that glycemic control is optimized. Early signs of complications must be recognized and interventions to limit their progression utilized. Screening of high-risk individuals to identify the estimated one-third of persons with diabetes who are undiagnosed, targeted education programs to the primary care professionals who deliver the majority of care to individuals with diabetes, implementation of the proven, cost-effective measures that can prevent (postpone) the complications of diabetes, monitoring of the health care delivery system and addressing the potential barriers to adequate care for all persons with diabetes are essential steps to decrease the burden of diabetes for South Carolinians (Table 1).

Demographic and educational differences in smoking in a tobacco-growing state.

National studies have documented an excessive rate of cigarette smoking in black men; however, a 1987 survey conducted in two urban areas in South Carolina documents a high rate of smoking in young white men with fewer than 12 years of education (67%; 95% confidence interval [CI] = 58.3, 75.7). Differences in smoking rates by educational level were significant only for those younger than 40. Young blacks were less likely to smoke and smoked fewer cigarettes than whites. As a result, the population burden of cigarettes in young black men with fewer than 12 years of education was only 27% of the burden carried by their white peers. Television, physicians, and radio were all seen as likely sources of health information to prevent heart disease, but newspapers were less likely to be cited by those younger than 40 or by those with fewer than 12 years of education. Reported physician counseling for smoking cessation did not differ significantly by race, sex, or educational level of the patient, but reported counseling was higher for individuals with a personal history of cardiovascular disease (odds ratio [OR] = 2.32, CI = 1.27, 4.25) and somewhat lower for the elderly. We highlight the population burden of cigarettes, a predictor of the eventual disease burden attributable to smoking, as a useful priority measure for smoking intervention efforts.

Cardiovascular functions during voluntary apnea in dogs.

We studied cardiovascular responses to apnea during voluntary snout immersion in conscious, chronically instrumented dogs. Voluntary snout immersion up to eye level for a duration of greater than 15 s ensured that the dog was engaged in active apnea. In a control apnea of 15-35 s, heart rate decreased by 43% from a control value of 104 beats/min. Changes in cardiac output paralleled those of heart rate. Mean aortic blood pressure did not vary during apnea, which, coupled with a reduced cardiac output, indicated a 65% increase in estimated total peripheral resistance compared with preapnea values. Treatment with atropine sulfate (0.2 mg/kg) eliminated the bradycardia response, but the peripheral vasoconstriction persisted. Treatment with propranolol (0.5 mg/kg) eliminated postapnea hypertension. Changes in myocardial contractility during apnea were observed by measuring hemodynamic parameters while maintaining a constant heart rate with cardiac pacing. Myocardial contractility was decreased during apnea as indicated by decreases in stroke volume (-13%), stroke work (-22%), cardiac output (-13%), left ventricular (dP/dt)max (-11%), and cardiac power (-24%). These changes were prevented by atropine treatment, indicating the depressed contractility was a result of vagus nerve activity. The circulatory adjustments in the dog during apnea are potential mechanisms for oxygen conservation, although the effectiveness is uncertain for the animal as a whole. It is clear that by appropriate reduction in cardiac power output, the heart itself plays an active role in conservation of limited oxygen during apnea.

A fabric pouch for maintaining transducer and catheter terminations.

Management of the chronically instrumented animal is improved by enclosing the terminations of catheters and transducer wires in a subcutaneous nylon velour pouch. Six or more days after implantation, an opening is made into the pouch by removing a portion of the overlying skin; subsequent healing processes provide a satisfactory bond. Thereafter the leads can be extracted and replaced without need for anesthesia or dissection. Results in 35 animals (26 dogs and 9 monkeys) for intervals up to four months showed fibrous encapsulation was complete in 28 and partial in 7, with no mortality or significant morbidity attributable solely to the presence of the pouch. Gross and microscopic tissue examination indicated a localized foreign body reaction in response to the nylon fibers. The technique is especially useful in experimental protocols for which continuous restraint is undesirable, such as the chronically instrumented primate periodically exposed to environmental stress.

Body acceleration distribution and O2 uptake in humans during running and jumping.

Body acceleration distribution and its relation to the mode of generation were determined in eight young males (19-26 yr) who walked and ran on a treadmill operated at four speeds and jumped on a trampoline at four heights. With increasing treadmill speed, peak acceleration at the ankle (Aa = 3.0-12.0 Gz) always exceeded that at the back and forehead (Ab = 0.9-5.0 Gz, and Ah = 0.8-3.9 Gz); these acceleration profiles included higher frequency components than those during jumping. Corresponding ranges of oxygen uptake (VO2) and heart rate (HR) were 0.8-3.0 l/min and 90-180 beats/min, respectively. With increasing jumping height, acceleration levels were more symmetrically distributed (Aa = 3.0-7.0 Gz, Ab = 3.9-6.0 Gz, and Ah = 3.0-5.6 Gz); VO2 and HR ranges were 1.1-2.5 l/min and 102-175 beats/min, respectively. VO2 was linearly related to HR for both types of exercise. The results indicate that, for similar levels of HR and VO2, the magnitude of the biomechanical stimuli is greater with jumping on a trampoline than with running, a finding that might help identify acceleration parameters needed for the design of remedial procedures to avert deconditioning in persons exposed to weightlessness.

Modification of cardiac function by synchronized oscillating acceleration.

The sensitivity of selected cardiovascular (CV) responses to the physical stressor of External whole-body oscillating Acceleration Synchronized with the Electrocardiogram (EASE) was analyzed in 8 chronically instrumented tranquilized dogs. A sinusoidal acceleration wave form was imposed on the supine animals along the spinal (+/- Gz) axis at a constant amplitude of +/- 0.75 G, and a frequency equal to the paced-heart frequency (2--3 Hz). When the peak force was positive in early systole, and negative in early diastole, changes in myocardial oxygen consumption (MVo2, + 8%), mean coronary flow (MCF, + 8%), stroke volume (SV, + 15%), cardiac work (CW, + 19%) and the time derivative of left ventricular pressure (dP/dt, + 18%) were minimal in comparison to nonoscillatory control values. When the peak force was positive in early diastole and negative in late diastole and early systole, changes in MVo2 (+ 41%), MCF (+ 39%), SV (+ 33%), CW (+ 50%), and dP/dt (+ 31%) were maximal. Thus the capability of EASE to produce a range of desired sustained CV responses provides a basis for its potential diagnostic/therapeutic applications.

Cardiac responses of dogs to nonsynchronous and heart synchronous whole-body vibration.

Changes in cardiac function produced by synchronizing vibration-induced forces with events in the cardiac cycle were compared to those for the nonsynchronous case in eight chronically instrumented, tranquilized dogs. The supine animals received sinusoidal, whole-body vibration (along the spinal +/- Gz axis) at a constant acceleration amplitude (+/- 0.75 G). The vibration frequency (2-3 Hz) was set equal to the paced heart frequency. Synchronization between vibration and cardiac cycles on a beat-by-beat basis produced a specific and sustained cardiovascular response; such a sustained response was not possible with nonsynchronous vibration. With synchronization, relationships could be found and sustained in which changes either exceeded or were below mean nonsynchronous levels, in some cases below previbration values. For the synchronous vs. nonsynchronous states, significant modification of cardiac function was reflected in parameters such as coronary flow (+15% to -34%) and myocardial oxygen consumption (+21% to -51%). Thus, whole-body oscillation acceleration (vibration) is a forcing function that can produce and maintain a particular cardiovascular response.

Continuous metabolic and cardiovascular measurements on a monkey subject during a simulated 6-day Spacelab mission.

In May 1977 the NASA Ames Research Center and NASA Johnson Space Center jointly conducted a test of the feasibility of performing various types of biological and medical experiments during future Spacelab flight missions. One of the experiments was designed to examine the effects of weightlessness on several basic parameters of metabolic and cardiovascular function in an adult nonhuman primate. The subject animal, a 10 kg male pig-tailed monkey (Macaca nemestrina), was prepared 3 months before the test with a surgically implanted NASA/Ames biotelemetry unit to provide continuous measurements of body temperature and selected cardiovascular parameters. Three days before the simulated "launch" the animal was inserted into a fiberglass pod system to provide continuous measurement of respiratory gas exchange. The pod system was installed in a Spacelab mock-up and all physiological data channels were recorded continuously for 2.6 days prior to "launch", for 6.3 days during "flight", and for 1.8 days after "landing". The experiment was tended entirely by the Spacelab flight crew during the "flight" period. Statistically significant diurnal variation was noted in oxygen consumption and carbon dioxide production rates, body temperature and heart rate, but not in respiratory quotient or blood pressure. A transient increase of the parametric values was noted during the latter portion of the "flight" period, possibly occasioned by increased flight crew activity. The high quality of the continuous data obtained during the 10.7-day total experiment period demonstrates the feasibility of performing sound physiological experimentation on nonhuman primates in the Spacelab environment.

An objective determination of +Gz acceleration tolerance.

Until recently, human +Gz acceleration tolerance has relied solely on subjective criteria relating to loss of vision. By use of newly developed noninvasive instrumentation using a transcutaneous Doppler flow system, objective end point criteria have been developed based on measured blood flow to the head. The system consists of miniature 8 MHz Doppler sensors (2 x 1 x 0.5 cm) placed on the forehead over both frontal branches of the temporal arteries to detect blood flow velocity from back scattered ultrasound. Its use has allowed for correlation of altered, decreased and actual reversal of eye level blood flow with subsequent central light loss. Over 100 subjects have now been studied during more than 2,000 centrifuge runs. Objective changes in temporal artery flow velocity consistently preceded visual degradation for each subject during all acceleration profiles. No subject has gone unconscious without first exhibiting a minimum 6 sec of total flow cessation. Retrograde flow followed by complete flow cessation always preceded central light loss. Results indicate that this method can be successfully used with a wide variety of tasks during exposure to +Gz acceleration. It is recommended for use during evaluation of protective maneuvers or devices on the centrifuge or during actual flight in high performance aircraft. It may also serve as a potential safety monitor during space Shuttle re-entry if there is doubt about a passenger's cardiovascular status.

Parameters for assessing vibration-induced cardiovascular responses in awake dogs.

The vibration parameters for assessing the response of the cardiovascular system to whole-body vibration were studied. Six awake, chronically instrumented canines were restrained with their spines vertical, and exposed to GZ sinusoidal vibration of 2-12 HZ for a constant peak acceleration amplitude of +-1.0 G. Vibration exposures of 30 s with intervening recovery periods of 2 min were employed. The following variables were measured: mean heart rate (MHR), stroke volume (SV), mean aortic flow (MAF), mean aortic pressure (MAP), the peak net force transmitted to the canine/body weight (PNF/BW), and the vibration platform frequency (ft), displacement, and acceleration. The percentage change from control (no vibration) of MAF varied linearly with PNF/BW for all cases. MAF also varied linearly with the log MHR/ft for the number of dogs which primarily changed MHR during the vibration exposures. The response of MAP was minimal in all cases, indicating a decrease in total peripheral resistance with increasing PHF.

A multichannel implantable telemetry system for flow, pressure, and ECG measurements.

The design of telemetry systems for chronic implantation within the body have progressed from simple single-channel devices to complex multichannel systems over the last 15 yr. Although chronic measurements of temperature, ECG, and pressure have been reported with good results, measurements such as dimension and blood flow have been difficult because of heavy power requirements. The design to be described is a multiplex system that will measure up to eight individual parameters simultaneously, including blood flow. Flow is measured using an electromagnetic transducer, and by special design, the normal high power requirements of the electromagnetic technique have been reduced to a few hundred milliwatts. The system is powered by two NiCad, rechargeable batteries which are periodically recharged through the intact skin by induction at 250 kHz to an implanted pickup coil. The presently constructed units have been configured to measure ECG, two pressures, temperature and ascending aortic flow.