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Biomedical subjects

D C Adams

Publications and source records attributed to D C Adams.

At least 55 records · Page 3Linked to original sources
PubMed1996

Effects of time of weaning, supplement, and sire breed of calf during the fall grazing period on cow and calf performance.

A 4-yr experiment was conducted to determine effects of protein supplementation, age at weaning, and calf sire breed on cow and calf performance during fall grazing. Each year 48 pregnant, crossbred cows nursing steer calves (mean calving date = April 8) were assigned to a 2 x 2 x 2 factorial experiment replicated in three native range pastures. Treatment factors were: 1) no supplement (NS) or an individually fed supplement (S, 3 kg of a 34% protein supplement fed to cows every 3rd d); 2) calves weaned at the beginning (W, mid to late September) or at the end (NW, mid to late December) of the trial each year; or 3) calves sired by Hereford or Charolais bulls. Data were adjusted for cow size (initial hip height and initial and final weights and condition scores) by analyses of covariance using principal component coefficients as covariates. Change in cow weight and condition score were increased by S and W (P < .01), but these responses interacted and were not the same each year (yr x S, year x W, and year x S x W, P < .01). Forage intake was decreased (P < .1) by S and W. Total intake (forage+supplement) was not affected by S but was decreased by W (P < .1). Digestibility of OM was decreased by S (P < .01). Some carryover effects of treatments were observed the next spring in cow weight, condition score, and birth weight (NW decreased birth weight by 2 kg, P < .01), but there were no effects by the next fall on weaning weights or pregnancy rates. Milk yield decreased during the experimental period, and S maintained higher milk production in late lactation (P < .01). Calf ADG was increased by S and Charolais sires (P < .01). Efficiency (grams of output/ megacalorie of input) was not affected by sire breed but was enhanced by S (P < .01). Our conclusions are that 1) effects of feeding a 34% protein supplement to cows were to increase calf gains and improve persistency of lactation and efficiency; 2) delaying weaning decreased cow weight and condition score; 3) effects of weaning age and protein supplementation were highly dependent on forage and environmental conditions in any given year; and 4) whatever effects existed in a given year did not carry over to effects on next year's production as measured by pregnancy rates and weaning weights.

Aging↗
PubMed1995

Rediscovering my values.

Six years ago, Douglas Adams took a "dangerous detour" off his life's path, temporarily losing his way, ethically and professionally. What allowed him to regain his footing? A return to vision and values. In an essay that speaks to fundamental issues in the lives of executives in all fields, Adams retraces his steps and shows readers how he made his way back.

Administrative Personnel↗
PubMed1995

Cerebral dysfunction after cardiac operations in elderly patients.

BACKGROUND: Cerebral injury remains a significant complication of cardiac operations. We determined the incidence of cerebral dysfunction in a population of elderly patients undergoing open chamber cardiac operations (group 1) as compared with a younger population (group 2) and an age-matched group of elderly patients undergoing major noncardiac operations (group 3). METHODS: Sixty-eight patients (55 for open chamber cardiac operations and 13 for noncardiac operations) were prospectively studied. Patients were evaluated preoperatively and postoperatively before hospital discharge using a complete neurologic examination and a battery of standard neuropsychometric tests, and at surgical follow-up with neuropsychometric tests only. RESULTS: Postoperative changes detected by neurologic examination consisted of the appearance of new primitive reflexes in all groups. No statistically significant differences in incidence were found. The neuropsychometric performance of group 1 patients was statistically different from that of patients in groups 2 and 3 only in the early follow-up period. CONCLUSIONS: Elderly patients having open chamber cardiac operations exhibit significantly more cerebral dysfunction in the early postoperative period than those undergoing major noncardiac operations and younger patients after open chamber procedures. These changes do not persist into the late follow-up period.

Age Factors↗
PubMed1995

Implantable cardioverter-defibrillator. Evaluation of clinical neurologic outcome and electroencephalographic changes during implantation.

During placement of implantable cardioverter-defibrillators, ventricular arrhythmias are induced to test the function of the devices. Although cerebral hypoperfusion and ischemic electroencephalographic changes occur in patients while implantable cardioverter-defibrillators are being tested, no investigation has assessed neurologic outcome in these patients. Nine patients having either implantation or change of an implantable cardioverter-defibrillator underwent neurologic examination and neuropsychometric tests before and after the operation. After induction of general anesthesia and insertion of implantable cardioverter-defibrillator leads (when needed), ventricular fibrillation, ventricular flutter, or ventricular tachycardia, was induced by means of programmed electrical stimulation. Implantable cardioverter-defibrillator testing continued until satisfactory lead placement was confirmed. The intraoperative electroencephalographic recording was analyzed for evidence of ischemic change. In all, an electroencephalogram was recorded during 50 periods of circulatory arrest. Mean duration of the arrest periods was 13.6 seconds. By means of conventional visual inspection of the raw electroencephalogram, high-amplitude rhythmic delta or theta, voltage attenuation, or loss of fast frequency activity was observed in 30 of the arrests. By means of an automated technique of electroencephalographic interpretation based on power spectral analysis, electroencephalographic changes were correctly identified in 26 of the arrests. The incidence of these electroencephalographic changes was dependent on the arrest duration. The mean interval from arrest onset to electroencephalographic change was 7.5 seconds (standard deviation +/- 1.8 seconds). In patients with electroencephalographic changes during multiple arrests, no downward trend in this interval was detected in later arrests and no evidence of persistent ischemic change was observed in electroencephalograms recorded after the conclusion of implantable cardioverter-defibrillator testing. Postoperative neurologic and neuropsychometric testing was completed in eight patients, none of whom exhibited a new neurologic deficit, exacerbation of a preexisting neurologic condition, or significant deterioration in neuropsychometric performance. We conclude that the brief arrest of cerebral circulation induced during insertion of an implantable cardioverter-defibrillator is not associated with permanent neurologic injury.

Adult↗
PubMed1995

The reliability of quantitative electroencephalography as an indicator of cerebral ischemia.

The electroencephalogram (EEG) has been used to detect episodes of cerebral ischemia during various surgical procedures. Recently, computerized systems for recording and interpreting the quantitative EEG (QEEG) have been used by anesthesiologists because of their ease of application, clarity of display, and reported ability to identify ischemic EEG changes. However, the extent to which automated techniques of QEEG interpretation reliably differentiate cerebral ischemia from the confounding effects of anesthetics and other sources of "artifact" is not completely established. In this study, EEGs were recorded before and after defibrillator testing in patients undergoing implantable cardioverter defibrillator (ICD) placement and during analogous time periods in control patients undergoing abdominal surgery. EEGs were subjected to standard visual inspection by an experienced electroencephalographer and QEEG analysis with a commercially available system was used for automated EEG interpretation in order to evaluate the reliability of this quantitative technique. The CIMON technique identified episodes which met previously defined criteria for QEEG cerebral dysfunction and ischemic pattern in both groups, despite the presumed absence of cerebral ischemia in the control patients. Since there was no evidence of cerebral ischemia in the raw EEGs of either the ICD patients or the controls, these QEEG changes were not confirmed by conventional techniques of EEG interpretation. Our results suggest that caution is warranted when using automated systems for intraoperative interpretation of EEG.

Adult↗
PubMed1995

Cerebral blood flow is determined by arterial pressure and not cardiopulmonary bypass flow rate.

BACKGROUND: During cardiopulmonary bypass, global hypoperfusion of the brain has been shown to result in ischemic insult and subsequent neurologic injury. Furthermore, outcome after focal cerebral ischemia depends on collateral circulation, which is determined by the parameters of global perfusion. We therefore measured cerebral blood flow during independent manipulations of arterial blood pressure and pump flow rate to determine which of these hemodynamic parameters regulates cerebral perfusion during cardiopulmonary bypass. METHODS: Seven anesthesized baboons were placed on cardiopulmonary bypass and cooled to 28 degrees C. Pump flow rate and arterial blood pressure were altered in varied sequence to each of four conditions: (1) full flow (2.23 +/- 0.06 L.min-1.m-2, mean +/- standard deviation) at high pressure (61 +/- 2 mm Hg), (2) full flow (2.23 +/- 0.06 L.min-1.m-2) at low pressure (24 +/- 3 mm Hg), (3) low flow (0.75 L.min-1.m-2) at high pressure (62 +/- 2 mm Hg), and (4) low flow (0.75 L.min-1.m-2 at low pressure (23 +/- 3 mm Hg). During each of these hemodynamic conditions cerebral blood flow was measured by washout of intracarotid xenon. RESULTS: Cerebral blood flow was greater at high blood pressure than at low pressure during cardiopulmonary bypass both at low flow (34 +/- 8.3 versus 14.1 +/- 3.7 mL.min-1 x 100 g-1) and full flow (27.6 +/- 9.9 versus 16.8 +/- 3.7 mL.min-1 x 100 g-1) (p < 0.01). At comparable mean arterial blood pressures alteration of pump flow rate produced no changes in cerebral blood flow. CONCLUSIONS: These results indicate that cerebral blood flow during moderately hypothermic cardiopulmonary bypass is regulated by arterial blood pressure and not pump flow rate.

Animals↗
PubMed1993

Autologous predonation, haemodilution and intraoperative blood salvage in elective abdominal aortic aneurysm repair.

The feasibility of predonated autologous blood transfusion and intraoperative blood salvage in elective abdominal aortic aneurysm repair was studied. Twenty consecutive patients were evaluated, of whom five were excluded according to protocol criteria. Patients each donated 1 unit blood 14 and 7 days before operation. A third unit was withdrawn in the anaesthetic room and replaced with Hartmann's solution, producing a haemodiluted state. Intraoperative losses were minimized using the Haemonetics Cell Saver III Plus autotransfusion system. Predonated blood from two patients passed its expiry date owing to repeated operation postponements, leaving 13 patients for study. The mean(s.d.) intraoperative blood loss was 700(300) ml with a mean(s.d.) intraoperative salvage of 420(300) ml. Two patients were transfused intraoperative salvage of 420(300) ml. Two patients were transfused according to clinical need. Thus nine patients safely avoided homologous transfusion. With autologous predonation, haemodilution and intraoperative blood salvage, elective aortic aneurysm repair can be performed safely with minimal need for homologous blood.

Aorta, Abdominal↗
PubMed1993

Scaphoid excision and capitolunate arthrodesis for radioscaphoid arthritis.

Eighteen patients with symptomatic radioscaphoid arthritis had scaphoid excision and capitolunate arthrodesis. Eight patients also had a silicone scaphoid replacement. The follow-up period averaged 3 years. Fusion was solid in 12 cases at an average of 8 weeks, and pain was significantly less at follow-up evaluation. Six patients had a pseudarthrosis and five had persistent pain. Immobilization in the pseudarthrosis group averaged 6 weeks, which was significantly less than the group that fused. Two patients underwent successful repeat fusions. Wrist extension averaged 26 degrees, flexion 34 degrees, radial deviation 11 degrees, and ulnar deviation 24 degrees. Grip strength averaged 25 kg. Presence of an implant had no significant effect on motion or strength. Pin track infection and pseudarthrosis were the main complications. Pain relief, functional motion, good strength, and patient satisfaction can be expected after scaphoid excision and solid capitolunate arthrodesis. Kirschner wires should be buried subcutaneously to avoid infection. The addition of a scaphoid implant offered no advantage over simple scaphoid excision.

Arthritis↗
PubMed1993

Familial abdominal aortic aneurysm: prevalence and implications for screening.

The high prevalence of abdominal aortic aneurysm (AAA) in men over the age of 65 has led to the establishment of ultrasound screening programmes for this group. The apparent familial tendency towards AAA formation suggests that relatives of aneurysm patients may form another subpopulation in whom screening is appropriate. The first degree relatives of 100 consecutive aneurysm patients were identified. Of 110 relatives over 50 years of age, two were known to have had AAA and ultrasound scans were performed on 74, providing information on aortic size for 76 relatives (69%). No further aortic aneurysms (antero-posterior diameter > or = 4.0 cm) were found on scanning. However, nine relatives were demonstrated to have aortic dilatation (2.5-3.9 cm). Aortic dilatation was observed in 21% of male first degree relatives over 50 years of age, affecting 27% of sons and 17% of brothers. Only 4% of the sisters and none of the daughters were found to have aortic dilatation. The prevalence of aortic enlargement seems to be sufficiently high amongst male first degree relatives of AAA patients over 50 years of age to justify aortic screening.

Aged↗
PubMed1993

Monitoring of intraoperative motor-evoked potentials under conditions of controlled neuromuscular blockade.

Motor-evoked potentials were recorded after electrical spinal cord stimulation in 19 patients undergoing neurosurgical or orthopedic procedures. Anesthesia was maintained with nitrous oxide, opioids, and inhaled anesthetics. Vecuronium was infused sufficient to eliminate 90% of twitch tension. The spinal cord was stimulated using either epidural or subarachnoid electrodes. Compound muscle action potentials were recorded from quadriceps and tibialis anterior muscles. Well-formed, stable motor-evoked potentials were recorded in all but one patient, in whom a preexisting myelopathy was felt to preclude recording. Intraoperative deterioration of motor-evoked potentials occurred in one patient who had a postoperative neurologic deficit. This study demonstrates the feasibility and utility of intraoperative motor tract monitoring using direct spinal cord stimulation. Controlled neuromuscular blockade permits recording of compound muscle action potentials while eliminating patient motor activity that could interfere with surgery.

Action Potentials↗
PubMed1993

Arthroplasty of the metacarpophalangeal joints with use of silicone-rubber implants in patients who have rheumatoid arthritis. Long-term results.

The long-term results of 144 arthroplasties of the metacarpophalangeal joints, with use of silicone-rubber implants, were reviewed for twenty-seven patients (thirty-six hands) who had rheumatoid arthritis. The operations were all performed or supervised by the same surgeon. All patients had an arthroplasty of the metacarpophalangeal joint of all four fingers, and all had subjective and objective clinical evaluation and roentgenographic assessment. Relief of pain, the cosmetic appearance of the hand, the range of motion of the metacarpophalangeal and proximal interphalangeal joints, and the presence of residual deformity were evaluated. The average duration of follow-up was eight years and six months (range, five years to sixteen years and three months). Preoperatively, the mean active-extension deficit of the metacarpophalangeal joints ranged from 53 degrees (index finger, right hand) to 70 degrees (little finger, left hand) and the mean flexion ranged from 84 degrees (index finger, right hand) to 94 degrees (little finger, left hand). At the early follow-up evaluation (average, four months postoperatively; range, two to six months), the mean extension deficit had improved to a range of 7 degrees (little finger, right hand) to 19 degrees (index finger, left hand), and mean flexion ranged from 56 degrees (little finger, left hand) to 66 degrees (ring fingers). The range of motion had improved from a non-functional arc of flexion to a more functional arc of extension. At the time of the latest follow-up visit, the motion of the metacarpophalangeal joints had not deteriorated.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Surgical discharge summaries: improving the record.

The problem area of communication between hospital and general practitioners may potentially be improved by the advent of new information technology. The introduction of a regional computer database for general surgery allows the rapid automated production of discharge summaries and has provided us with the opportunity for auditing the quality of old and new styles of discharge communication. A total of 118 general practitioners were sent a postal questionnaire to establish their views on the relative importance of various aspects of patient information and management after discharge. A high response rate (97%) indicated the interest of general practitioners in this topic. The majority (73%) believed that summaries should be delayed no more than 3 days. The structured and shortened new format was preferred to the older style of discharge summary. The older format rarely arrived within an appropriate time and its content was often felt to be either inadequate (35%) or excessive (7%) compared with the new format (8% and 1%, respectively). The diagnosis, information given to the patient, clinic date, list of medications and investigations were considered the more important details in the summary. Improvements in the discharge information were suggested and have subsequently been incorporated in our discharge policy. The use of new information technology, intended to facilitate clinical audit, has improved our ability to generate prompt, well-structured discharge summaries which are accepted by the general practitioners.

Attitude of Health Personnel↗
PubMed1992

Endoscopic transthoracic sympathectomy: experience in the south west of England.

Thoracic sympathectomy has an established role in the management of primary palmar and axillary hyperhidrosis, Raynaud's phenomenon and occlusive vascular disease. Potential problems with traditional surgical approaches to the sympathetic chain include poor exposure, risk of damage to adjacent structures and postoperative pain. A minimally invasive endoscopic approach helps to overcome these problems. Using this technique, 45 procedures have been performed on 26 patients in two districts in the South West of England over the past five years. Follow-up information was available for 39 procedures. All 27 procedures for hyperhidrosis and both for occlusive vascular disease have produced a long-term improvement. Nine of the 10 procedures for Raynaud's phenomenon have also produced some degree of long-term improvement. Complications included four asymptomatic pneumothoraces, two patients with temporary unilateral Horner's syndrome and two instances of intercosto-brachial numbness. On the positive side, patients expressed satisfaction with the efficacy, rapid recovery and small unobtrusive scars produced by the procedure. Endoscopic transthoracic sympathectomy is effective, safe and well accepted by patients and we believe is now the method of choice for this procedure.

Adolescent↗