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Biomedical subjects

R S Howard

Publications and source records attributed to R S Howard.

At least 73 records · Page 4Linked to original sources
PubMed1997

Do-not-resuscitate decisions in the medical ICU: comparing physician and nurse opinions.

STUDY OBJECTIVE: To determine how soon after admission to a medical ICU physicians and nurses decide that attempts at resuscitation are inappropriate and how frequently physicians and nurses disagree about do-not-resuscitate (DNR) decisions. DESIGN: Prospective, opinion survey of care providers. SETTING: Ten-bed adult medical ICU in a university-affiliated tertiary care referral hospital. PATIENTS: Consecutive adult medical ICU admissions. INTERVENTIONS: Over 10 months, physicians and nurses were surveyed independently every day regarding their opinions about DNR issues on each patient in the ICU. MEASUREMENTS: ICU day when DNR order was deemed appropriate by either physicians or nurses. RESULTS: Of 368 consecutive admissions, 84 (23%) patients were designated DNR during their ICU stay. In 6 of these 84 cases (7%), the responsible nurse did not agree that DNR orders were appropriate. In the remaining 78 patients designated DNR, the median time for physicians to recommend DNR (median, 1 day; range, 0 to 22 days) was not significantly different from the median time for nurses (median, 1 day; range, 0 to 13 days); (p=0.45). For the 284 patients not designated DNR, physicians and nurses both believed DNR was appropriate in 14 cases (5%), but a DNR order was not written five times (2%) because there was not time to do so and nine times (3%) because patient or family did not concur. Physicians and nurses disagreed about a DNR recommendation in 33 of the 284 patients not designated DNR (12%). Physicians were more likely to believe that DNR was appropriate than were nurses (p<0.0005), with physicians alone recommending DNR 29 times (10%) and nurses alone favoring DNR in four cases (1%). CONCLUSIONS: At our institution, recognition of DNR appropriateness by nurses and physicians occurs over a similar time frame. However, physicians are more likely to recommend DNR in cases of disagreement between nurses and physicians.

Aged↗
PubMed1997

Evaluation of an enzyme-linked immunosorbent assay in Thai scrub typhus patients.

We report the development of an improved enzyme-linked immunosorbent assay (ELISA) to detect Orientia (formerly Rickettsia) tsutsugamushi antibody in human sera. Results were compared with a standard test, the indirect immunoperoxidase assay (IIP). Control serum samples were collected from 96 American soldiers and 198 Royal Thai Army soldiers with no recent history of clinical illness. Sera were examined from 79 febrile, Thai scrub typhus patients presenting at Chiang Rai (76) and Bangkraui Nontaburi (3) Provincial hospitals (cases confirmed by elevated IIP IgG levels > or = 1:1,600, IgM levels > or = 1:400, or presence of an eschar). The mean + 2 SD, used for the upper limit of normal reactions in the IgG ELISA, was 0.10 for U.S. soldiers and 0.42 for Thai soldiers. Using the 0.10 cutoff value, 29% of the asymptomatic Thai soldiers would be designated as antibody positive. Variability of IgG ELISA values was greater in the Thai soldier group than in American soldiers, possibly reflecting previous exposure to O. tsutsugamushi. In the Thai patients, there was a significant correlation between IIP titers and single serum dilution (1:100) ELISA values (IgG, r = 0.75, n = 104; P < 0.0005; IgM, r = 0.70, n = 75; P < 0.0005) and between IIP titers and ELISA titers (IgG, r = 0.87, n = 103; P < 0.0005; IgM, r = 0.76, n = 75; P < 0.0005). The single serum dilution ELISA was as effective as the titration in determining presence of specific antibodies. The O. tsutsugamushi ELISA is a rapid and objective test amenable to accurately testing the large numbers of sera often obtained in seroepidemiologic investigations.

Animals↗
PubMed1996

Infection and allergy incidence in ambulatory surgery patients using white petrolatum vs bacitracin ointment. A randomized controlled trial.

OBJECTIVE: To assess the effect of white petrolatum vs bacitracin ointment on wound infection incidence, allergic contact dermatitis incidence, and healing characteristics. DESIGN: Randomized, double-blind, prospective trial comparing white petrolatum with bacitracin ointment in postprocedure wound care. SETTING: A general outpatient dermatology clinic and a tertiary referral advanced surgical procedure clinic at Walter Reed Army Medical Center, Washington, DC. PATIENTS: A total of 922 patients who had dermatologic surgery with a total of 1249 wounds. MAIN OUTCOME MEASURES: The incidence of infection and allergic contact dermatitis during a follow-up period of 4 weeks. Healing characteristics were secondary outcomes. RESULTS: Of the 922 patients enrolled, 440 in the white petrolatum group and 444 in the bacitracin group were evaluable for clinical response. The 2 treatment groups had comparable baseline characteristics. Thirteen patients developed postprocedure infection (1.5%), 9 (2.0%) in the white petrolatum group vs 4 (0.9%) in the bacitracin group (95% confidence interval for difference, -0.4% to 2.7%; P=.37). Eight infections (1.8%) in the white petrolatum group were due to Staphylococcus aureus vs none in the bacitracin group (P=.004). No patient in the group using white petrolatum developed allergic contact dermatitis vs 4 patients (0.9%) in the group using bacitracin (P=.12). Additionally, there were no clinically significant differences in healing between the treatment groups on day 1 (P=.98), day 7 (P=.86), or day 28 (P=.28) after the procedure. CONCLUSIONS: White petrolatum is a safe, effective wound care ointment for ambulatory surgery. In comparison with bacitracin, white petrolatum possesses an equally low infection rate and minimal risk for induction of allergy.

Adult↗
PubMed1996

Necessity of routine chest roentgenography after thoracentesis.

OBJECTIVE: To determine the necessity of posteroanterior chest roentgenography for the identification of pneumothorax and other complications after thoracentesis. DESIGN: Prospective cohort study. SETTING: Tertiary care teaching hospital. PATIENTS: 67 men and 43 women (mean age +/- SD, 62.4 +/- 13.2 years). Exclusion criteria included age younger than 18 years, concurrent pleural biopsy, ultrasound guidance, and use of mechanical ventilation. MEASUREMENTS: 174 thoracenteses done between March 1991 and June 1993. RESULTS: 2 hemothoraces (1.2%) occurred, and 8 patients had a total of 9 pneumothoraces (5.2%). The roentgenograms obtained immediately after the procedures identified 8 pneumothoraces; the other pneumothorax was seen incidentally on a delayed roentgenogram obtained 3 days later. Pneumothorax was suspected in 5 of the 8 cases, and tube thoracostomy was done in 4 of these 5 cases. Patients with unsuspected pneumothorax identified on the roentgenogram obtained immediately after the procedure did not receive treatment for their pneumothoraces. Univariate analysis showed that the variables that correlated significantly with pneumothorax were aspiration of air during the procedure (relative risk ratio, 12.3; 95% CI, 3.7 to 41.4), number of passes with the thoracentesis needle (relative risk ratio, 6.1; CI, 1.6 to 23.3), history of thoracic radiation therapy (relative risk ratio, 10.5; CI, 2.5 to 44.4), and operator suspicion of pneumothorax (relative risk ratio, 25.9; CI, 8.6 to 78.5). CONCLUSION: Among hospitalized patients with pleural effusions, we identified subgroup of patients in whom the risk for pneumothorax is low enough (approximately 1%) with sufficiently minimal clinical consequences to justify the avoidance of about 60% of chest roentgenograms obtained after thoracentesis. These patients are clinically stable, have not previously received chest irradiation, had only one pass at thoracentesis attempted without the aspiration of any air, and give no other indication of pneumothorax.

Aged↗
PubMed1996

Reduced brain stem excitability in mitochondrial myopathy: evidence for early detection with blink reflex habituation studies.

Blink reflex (BR) was studied in 17 patients with histochemically and genetically confirmed mitochondrial myopathy (MM). Fourteen patients had chronic progressive external ophthalmoplegia (CPEO) associated with a mild to moderate craniosomatic myopathy without any symptoms or signs of central nervous system (CNS) involvement, 2 myoclonic epilepsy with ragged red fibers syndrome, and 1 Kearns-Sayre syndrome. The mean latencies of the early (R1) and late (R2) responses were prolonged (P < 0.01 and P < 0.001, respectively), and the corresponding amplitudes decreased (P < 0.001). Increased habituation of the reflex was clearly observed in 10 out of 14 patients tested (71.4%), 9 of whom presented CPEO. These findings suggest that the brain stem reticular network is in a state of basal inhibition which is presumably due to a subclinical impairment of the cerebral cellular metabolism. Multimodal evoked potentials revealed abnormalities suggestive of CNS involvement in 7 out of 17 patients (41.2%), 4 of whom had CPEO. These observations document the validity of BR in detecting clinically silent brain stem impairment in patients with apparently pure MM and provide important clues for a further understanding of the underlying pathophysiology.

Adolescent↗
PubMed1996

Brainstem encephalopathy with stimulus-sensitive myoclonus leading to respiratory arrest, but with recovery: a description of two cases and review of the literature.

Two unrelated patients developed bulbar symptoms, followed within several weeks by spontaneous myoclonus and painful, generalized, stimulus-sensitive jerks triggered by unexpected noises and cutaneous stimuli. They progressed to respiratory arrest and required mechanical ventilation, but both patients subsequently made an almost full recovery. These cases stress the importance of persevering with supportive treatment despite rapid progression of this severe generalized movement disorder. The relationship of brainstem reflex myoclonus to hyperekplexia, progressive encephalomyelitis with rigidity, and the stiff-man syndrome is discussed.

Adult↗
PubMed1996

Functional activation during an auditory comprehension task in patients with temporal lobe lesions.

Functional magnetic resonance imaging (fMRI) was used to map regional brain activation during an auditory comprehension task in two normal controls and two patients with left temporal lobe lesions. Activity in the superior temporal and angular gyrus regions was detected in all normal subjects. In the patients, the spatial distribution of activation ipsilateral to the lesions differed from the pattern observed in contralateral cortex or in control subjects. These studies highlight the potential of fMRI for mapping abnormal functional anatomy in the human brain.

Adult↗
PubMed1996

Control of breathing in man; insights from the 'locked-in' syndrome.

Control of breathing was studied in a patient with a lesion in the ventral pons; no volitional behaviour, including voluntary breathing acts, was possible (locked-in syndrome, LIS). Spontaneous breathing via a tracheostomy maintained a normal PETCO2 of 39-40 mmHg. Variability of ventilatory parameters awake was similar to that seen in five tracheostomized control subjects during stage IV sleep but much smaller than during resting wakefulness. Emotion associated with laughter caused disturbances of breathing. The ventilatory response to CO2 was normal and was associated with 'hunger for air' when the PETCO2 was 49-50 mmHg. Mechanical ventilation to reduce PETCO2 by as little as 1 mmHg resulted in apnoea when the ventilator was disconnected; breathing resumed when PETCO2 crossed the threshold of 39-40 mmHg. These results demonstrate the functional dependence of the human medullary respiratory oscillator on a threshold level of PCO2 in the absence of cortico-bulbar input, even during wakefulness. The absence of such input may explain the regularity of breathing.

Adult↗
PubMed1996

Mitochondrial encephalopathy with multiple mitochondrial DNA deletions: a report of two families and two sporadic cases with unusual clinical and neuropathological features.

A mitochondrial myopathy associated with multiple deletions of mitochondrial DNA has been identified in pedigrees showing an autosomal dominant mode of inheritance. We report the first two British kindreds with this disorder, and two sporadic cases. The families exhibited some unusual clinical features, including pigmentary retinopathy and tremor; the latter was levodopa-responsive and associated with rigidity and micrographia in one family. Members of one pedigree and both sporadic patients had a peripheral neuropathy and nerve biopsy showed marked axonal degeneration. Post-mortem examination of one patient without parkinsonism showed severe neuronal loss in the substantia nigra.

Adult↗
PubMed1996

Diagnosis and treatment of status epilepticus on a neurological intensive care unit.

Status epilepticus refractory to first-line therapy is associated with a high morbidity and mortality. Correct diagnosis and adequate treatment of this condition require electrographic monitoring and anaesthetic facilities available in specialist intensive care units (ICUs). We carried out an audit of 26 patients admitted to a neurological ICU with a diagnosis of status epilepticus, to identify deficiencies in diagnosis and management prior to transfer to the ICU, and examine the effectiveness of ICU management. Or transfer, only 14 (54%) were in status epilepticus; six were in drug-induced coma or were encephalopathic, and six had pseudostatus epilepticus, of whom four had been intubated. The commonest treatments prior to transfer were benzodiazepines, chlormethiazole and phenytoin; the loading dose of phenytoin was adequate in at least 7/16 cases. All those in status epilepticus on transfer had their seizures successfully controlled, but ten required general anaesthesia with thiopentone, propofol, ketamine or midazolam. Two died--one had a severe encephalitis and the other had had a cardiac arrest prior to treatment. This study highlights deficiencies in the initial diagnosis and management of status epilepticus, the role of specialist neurological intensive care, and the importance of early referral.

Adolescent↗
PubMed1996

Respiratory insufficiency in neuronopathic and neuropathic disorders.

Twenty-nine patients with a neuronopathic or neuropathic disorder were referred for assessment of respiratory insufficiency between 1978 and 1994. Diagnoses included spinal muscular atrophy (6), chronic idiopathic demyelinating neuropathy (4), Vialetto-van Laere syndrome (3), hereditary motor and sensory neuropathy (3) and a miscellaneous group (5). We also describe seven patients with Guillain-Barré syndrome (GBS) who required long-term ventilatory support for over 6 months to 7 years after the initial illness. Respiratory insufficiency occurred as a consequence of respiratory muscle weakness, impaired bulbar function and restrictive lung defects. In some groups presentation was with progressive nocturnal hypoventilation culminating in acute respiratory failure. Five patients with GBS or chronic idiopathic demyelinating neuropathy were weaned from ventilatory support up to 18 months after the initial illness. The remaining 24 patients required continuous or nocturnal ventilatory support using intermittent positive-pressure ventilation (13), negative pressure ventilation (4), nasal-mask-delivered intermittent positive-pressure ventilation (4), nasal-mask-delivered continuous positive-pressure ventilation (3), mouthpiece-assisted ventilation by day (2) and rocking bed (1). None have been weaned from support after a period of ventilation ranging from one month to 10 years. Eight patients have subsequently died.

Adolescent↗
PubMed1996

Plasma potassium response after tromethamine (THAM) or sodium bicarbonate in the acidotic rabbit.

The purpose of this study was to evaluate the plasma potassium (K+) response after administration of tromethamine (THAM) or sodium bicarbonate (NaHCO3) in an acidotic rabbit model. Eighteen healthy, adult female New Zealand White rabbits were subjected to severe hypoxia until a base deficit of -10 mEq/L resulted. Rabbits were then randomized to receive THAM solution, NaHCO3, or no drug (control). The drug was administered over 2 min in quantities calculated to correct a base deficit of 10 or greater. Plasma K+ and sodium (Na+) were measured for 45 min after drug administration. No difference in K+ response was noted after THAM, NaHCO3, or no drug. In contrast, THAM resulted in significantly lower Na+ concentrations when compared to the NaHCO3 or the control group (P < 0.05). In this rabbit model, alkalinization after THAM administration results in K+ changes similar to those after NaHCO3. THAM should be considered when treating acidosis in patients where hypernatremia is a concern.

Acidosis↗
PubMed1996

Functional magnetic resonance imaging of regional brain activity in patients with intracerebral gliomas: findings and implications for clinical management.

Functional magnetic resonance imaging (fMRI) was performed in seven patients harboring intracerebral gliomas proven by histological analysis using a noninvasive blood oxygen level-dependent technique based on the documented discrepancy between regional increases in blood flow and oxygen use in response to regional brain activation. We combined fMRI with conventional magnetic resonance imaging (MRI) during motor or language task activation experiments to investigate the potential usefulness of mapping regional brain activity as part of treatment planning in patients with intracerebral gliomas, in whom preservation of areas of functioning brain tissue is critical. Statistical fMRI maps were generated and directly mapped onto conventional MRI scans obtained at the same session. Of the five patients cooperative enough to remain motionless for the study and perform the task, the location of activation in the primary sensorimotor cortex on the side of the tumor was clearly displaced compared with that in the normal contralateral hemisphere in four patients. Four of the five tumors in these patients showed fMRI activation within the periphery of (or immediately adjacent to) areas of presumed tumor based on spin-echo MRI. In some patients with neurological deficit, the extent of activation was reduced on the side of the tumor as compared with the normal hemisphere. The supplemental motor area and the ipsilateral primary motor cortex were also reproducibly activated during motor tasks. We conclude that blood oxygen level-dependent fMRI can localize areas of cortical function in patients undergoing treatment planning for gliomas so that therapy can be directed away from regions of residual function. Our preliminary data suggest that functioning cortex within or adjacent to tumor margins can be demonstrated, which may correspond to partial preservation of clinical function. Our preliminary data also suggest that there may be a quantifiable difference on fMRI between activation in tumor-bearing cortex and activation in corresponding normal cortex in the contralateral hemisphere. We postulate that the magnitude of this difference may relate to the severity of patient deficit.

Adolescent↗
PubMed1996

Enterovirus infection of the central nervous system of humans: lack of association with chronic neurological disease.

We have searched, using a sensitive nested-PCR, for enterovirus RNA in cerebrospinal fluid and post mortem central nervous system (CNS) tissue from patients with previous poliomyelitis with or without late functional deterioration, patients with motor neuron disease (MND), and control patients with other neurological disease or without neurological disease. Enterovirus RNA was detected in patients with previous poliomyelitis and MND, but also in control patients with and without neurological disease. Our results do not provide any evidence that such enterovirus infection is related to late functional deterioration in patients with previous poliomyelitis, which could be attributed to other medical conditions in most instances, and do not support the hypothesis that MND is associated with enterovirus infection of the CNS. Nucleotide sequence analysis of enterovirus RNA sequences detected indicated that enteroviruses detected were of the non-polio type.

Adult↗
PubMed1996

Clinical, CSF, and MRI findings in Devic's neuromyelitis optica.

OBJECTIVES: Since Devic's original description of neuromyelitis optica in 1894 there has been much debate regarding its aetiology. A specific cause has been identified in a minority of cases but in most the question has arisen whether or not Devic's neuromyelitis optica is a variant of multiple sclerosis. This study was undertaken to help clarify this issue. METHODS: Neuromyelitis optica was defined as (1) a severe transverse myelitis; (2) an acute unilateral or bilateral optic neuropathy; (3) no clinical involvement beyond the spinal cord or optic nerves, and (4) a monophasic or multiphasic illness. The clinical and autoantibody status was documented. Patients underwent CSF examination and MRI of brain and spinal cord. RESULTS: Twelve patients, with a mean age of presentation of 35.1 years, were seen. Eleven were women; vision was reduced to counting fingers or worse in 10 patients and seven became confined to a wheelchair. Examination of CSF showed local synthesis of oligoclonal bands in only two patients and a neutrophil pleocytosis in two. A possible aetiology was identified in five: a specific connective tissue disorder (two), pulmonary tuberculosis (one), and possible acute disseminated encephalomyelitis (two). Six had non-specific increases in various autoantibodies. Eleven patients underwent MRI of the brain and spinal cord. In 10 there were diffuse abnormalities involving cervical and thoracic cords with extensive swelling in the acute phase. Brain MRI was normal in five; in five there were multiple deep white matter lesions, and one patient had minor age related changes. CONCLUSION: It is proposed that Devic's neuromyelitis optica is a distinctive disorder with some clinical, CSF, and MRI features different from those found in classic multiple sclerosis. In most cases a specific aetiology is not identified, but an immunological mechanism of tissue damage seems likely.

Adolescent↗
PubMed1996

Nocturnal and respiratory disturbances in Steele-Richardson-Olszewski syndrome (progressive supranuclear palsy).

Respiratory and sleep disturbances may be important causes of morbidity in Steele-Richardson-Olszewski syndrome but the frequency and character of nocturnal abnormalities remains uncertain. A prospective study of 11 patients with Steele-Richardson-Olszewski syndrome and age-matched control subjects was undertaken using clinical assessments, a structured sleep questionnaire, spirometry, static maximum inspiratory and expiratory pressures and nocturnal oximetry. The mean age of the Steele-Richardson-Olszewski syndrome patients was 63.2 (52-70) years and mean disease duration was 4.0 (2-6) years. There was moderate to severe motor disability in nine and mild to moderate dementia in eight. In the patients with Steele-Richardson-Olszewski syndrome the following abnormalities contributed to sleep disturbances significantly more frequently than in normal controls: depression, dysphagia, frequent nocturnal awakenings (usually associated with urinary frequency), immobility in bed, difficulty with transfers, impaired dressing and feeding. There was profound impairment of voluntary respiratory control whilst automatic and limbic control were well maintained. Nocturnal respiratory abnormalities were not present even in the most severely disabled. In Steele-Richardson-Olszewski syndrome sleep abnormalities are common; they relate to the cognitive, pseudobulbar and extrapyramidal disturbances and may therefore be amenable to symptomatic control.

Aged↗