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Biomedical subjects

R L Carpenter

Publications and source records attributed to R L Carpenter.

14 recordsLinked to original sources
PubMed1992

Lidocaine 0.5% spinal anaesthesia: a hypobaric solution for short-stay perirectal surgery.

The efficacy of subarachnoid injection of 8 ml lidocaine 0.5% was assessed in ten outpatients having perirectal surgery in the jackknife position. This solution is hypobaric, with a baricity 0.9985 +/- 0.0003 (mean +/- SD). Injections were made with the patient in the surgical position (with the upper torso at a 15 degrees downward inclination). Sensory level was tested by pinprick. Times to two-segment regression, to complete resolution of sensory analgesia, to urination, and to discharge from the recovery room were recorded. All injections produced effective anaesthesia for surgery. Lidocaine 0.5% behaves clinically as a hypobaric solution. Dermatomal levels remained low (T11 to L5) while the patients were in the surgical position (head down), but rose two to six dermatomes if the patient's head was elevated after surgery. Time to two-segment regression was 97 +/- 36 min, time until regression to S1 was 116 +/- 22 min, time to complete resolution of sensory blockade was 151 +/- 23 min, time to urination was 197 +/- 64 min, and time to discharge from the recovery room was 205 +/- 45 min. Lidocaine 0.5% provides effective spinal anaesthesia of short duration appropriate for outpatient surgical procedures. Dermatomal sensory spread of anaesthesia, and our measurements of specific gravity, indicate that this solution is hypobaric. It appears that changes in position can alter the spread of analgesia for at least one hour after injection and, thus, we caution against elevating the patient's head in the immediate postoperative period.

Adult↗
PubMed1992

A randomized comparison of intravenous versus lumbar and thoracic epidural fentanyl for analgesia after thoracotomy.

Administration of large doses of fentanyl is a popular method to provide postoperative analgesia after thoracotomy. It is however unclear whether epidural lumbar (L) or epidural thoracic (T) administration of fentanyl confers any major advantage over intravenous (iv) infusion. Using a randomized prospective study design, we compared the potential benefits of L, T, and iv fentanyl administration after thoracotomy in 50 patients. Epidural catheters were not injected during surgery. Postoperatively a fentanyl infusion (5 micrograms/ml) was started at 1 microgram.kg-1.h-1 after a bolus of 1 microgram/kg and adjusted to maintain a score < or = 30/100 at rest using a visual analog scale (VAS) for pain. Data were prospectively collected before surgery, at fixed intervals during the 48 h of fentanyl infusions, and the day of discharge. There was no difference between the groups in overall quality of analgesia at rest and after coughing, quantity of fentanyl delivered (L = 1.15 +/- 0.38, T = 1.22 +/- 0.23, iv = 1.27 +/- 0.3 micrograms.kg-1.h-1), incidence of pruritus needing treatment (L = 2, T = 1, iv = 0 patients), need to decrease fentanyl infusion rate because of side effects (L = 2, T = 2, iv = 4 patients), importance of pulmonary infiltrates, or arterial blood gas values. One patient (L group) needed naloxone (0.04 mg iv). Intravenous patients were more frequently nauseated (P = .009) and needed boluses of fentanyl more often (L = 3 +/- 9, iv = 6 +/- 12, T = 4 +/- 8; P = .04).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1979

Toxicity of 0.4- and 0.8-microm sulfuric acid aerosols in the guinea pig.

To determine mortality caused by inhaled sulfuric acid mist, groups of Hartley guinea pigs 2-3 mo old were exposed for 8 h to graded concentrations of aerosols of 0.4 or 0.8 microm mass median aerodynamic diameter. Relative humidity during exposures was maintained at 70-80%. Based on probit analysis, the concentration required to produce 50% mortality (LC50) for deaths to 21 d after exposure was 30 mg/m3 for the 0.8-microm aerosol. For the 0.4-microm aerosol, the LC50 was above 109 mg/m3, the highest concentration obtainable at that particle size. At both particle sizes, the animals either tended to develop severe dyspnea and die minutes (0.4 microm) or hours (0.8 microm) thereafter or appeared nearly unaffected. Lesions in animals that died as a results of 0.4-microm exposures were restricted to hyperinflation; animals that died as a result of 0.8-microm exposures also showed hemorrhage and transudation. No gross or histopathologic changes were observed in animals that appeared unaffected during exposure. Differences in total and/or regional respiratory tract deposition may account for the different responses to the two aerosols.

Aerosols↗
PubMed1978

Elicitor effects on the language obtained from young language-impaired children.

Language samples are typically obtained during speech and language evaluations by the speech-language pathologist to assess the level of expressive language development of young children. These samples are assumed to be accurate representations of the children's language skills. This study examines the effects of the elicitor on the language obtained from three- to six-year-old language-impaired children in a clinical setting. A corpus of nonimitated utterances was collected in 25 min from each of the nine subjects under two conditions: mother as elicitor and clinician as elicitor. The corpus of language collected under each condition was examined using the following measures: (1) numeric-number of utterances; (2) lexical-vocabulary type-token ratio: (3) grammatic-mean length of utterance, (4) percentage of one-morpheme utterances, (5) percentage of two-morpheme utterances, (6) percentage of three- or more morpheme utterances, (7) proportion of grammatical morphemes per utterance (8) semantic-percentage occurrence of semantic categories, and (9) type-token ratio for each of the 13 semantic categories. The data analysis revealed that the elicitor affected the number of utterances collected in a specific time period, but neither the lexical, grammatic, nor semantic aspects of the utterances were affected. The results state practical implications for evaluation procedures used in a clinical setting.

Child Language↗
PubMed1976

Development of acoustic cue discrimination in children.

Three groups of twelve subjects each, ages four, five and six years, respectively, made same-different judgments on six speech discrimination tests. On each test, a single acoustic cue signaled a phonemic difference in minimal pairs which were otherwise acoustically identical. On three of the tests, the independent variable was a spectral cue and on three others a temporal cue was manipulated. With one exception, all subjects passed tests involving a spectral cue, however, significant developmental differences were apparent on tests in which a temporal cue signaled a phonemic difference. The probable contribution of these cues to the perception of speech in young children is discussed.

Auditory Perception↗
PubMed1976

Semantic relations used by normal and language-impaired children at stage I.

Two-word utterances of four language-impaired children at Brown's Stage I level of linguistic development were compared with two-word utterances of four young normal children at the same linguistic level to determine any differences between the two groups in the use of a set of 10 basic semantic relations. Type-token ratios for each semantic relation were used to compare use of semantic relations between groups. A significant difference was obtained for only one relation, with the language-impaired group demonstrating greater diversity in the use of the introducer + entity relation than the normal group. The findings indicated that at Stage I level of linguistic development, the language-impaired children demonstrated a linguistic system no different than the system of normal Stage I children. The findings are discussed relative to possible cognitive and linguistic strategies involved in language acquisition. It is suggested that some language-impaired children rather than being deficient in their ability to understand and code the basic semantic relations demonstrate a deficit in the higher, more complex aspects of the linguistic coding system.

Child, Preschool↗
PubMed1975

Sequelae of central-nervous-system enterovirus infections.

The long-term effects of central-nervous-system enterovirus infections were examined in a controlled follow-up study of 19 children 2 1/2 to eight years of age who had been hospitalized with documented enterovirus infection 17 to 67 months before evaluation. Assessment included medical history, physical and neurologic examination, psychologic testing, and speech and hearing evaluation. Three children (16 per cent) had definite neurologic impairment, five (26 per cent) had possible impairment, and 11 (58 per cent) were free of detectable abnormalities. Children whose illness occurred during the first year of life, when compared to controls, were found to have significantly smaller mean head circumference (50.6 vs. 51.6 cm, P less than 0.033), significantly lower mean I.Q. (97 vs 115, P less than 0.007), and depressed languange and speech skills. Children whose illness occurred after the first year of life were not different from their controls. Children whith central-nervous-system enterovirus infection may have neurologic impairment when infection occurs in the first year of life.

Age Factors↗
PubMedDate not supplied

Effect of local anesthetic concentration on capillary blood flow in human skin.

OBJECTIVES: The objective of this study was to evaluate and compare the effect of lidocaine, mepivacaine, and bupivacaine on capillary blood flow in humans over therapeutic and subtherapeutic concentrations. METHODS: The effect of each treatment in eight unmedicated male volunteers was measured in a randomized, controlled, double-blind comparison. Each participant received subcutaneous injections (total, 14), at separate sites on the abdomen, consisting of 0.2 ml lidocaine (0.05%, 0.5%, 1%, and 2%), mepivacaine (0.05%, 0.5%, 1%, and 2%), bupivacaine (0.025%, 0.25%, 0.5%, and 0.75%), saline, or saline with epinephrine (5 micrograms/ml), and at an additional site a needle stick was performed and no injection made. Cutaneous blood flow was measured with a laser Doppler capillary perfusion monitor before and for 60 minutes after these interventions. RESULTS: The maximum increase in cutaneous blood flow was 277 +/- 141% to 511 +/- 136% (mean +/- SE) after lidocaine, 124 +/- 110% to 316 +/- 155% after mepivacaine, and 242 +/- 193% to 725 +/- 198% after bupivacaine. The increase in blood flow depended on local anesthetic concentration: low concentrations induced minimal changes, whereas higher concentrations caused great increases in cutaneous blood flow. Injection of saline or needle stick alone increased cutaneous blood flow 285 +/- 237% and 260 +/- 121%, respectively. CONCLUSIONS: Our findings indicate that the trauma of needle stick or saline injection produces a significant increase in cutaneous capillary blood flow. Injection of clinically useful concentrations of bupivacaine and lidocaine produced even greater increases in capillary blood flow, indicating a vasodilatory effect. Injection of the lowest concentrations of lidocaine and bupivacaine caused flow to increase to a magnitude similar to that after injection of saline. In contrast, clinically useful concentrations of mepivacaine do not increase capillary blood flow to a greater extent than saline, and lower concentrations tend to blunt the increase in blood flow, indicating a mild vasoconstrictor effect.

Adult↗