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Biomedical subjects

R Hickey

Publications and source records attributed to R Hickey.

49 records · Page 3Linked to original sources
PubMed1989

Subclavian perivascular block: influence of location of paresthesia.

Subclavian perivascular block of the brachial plexus was used in 156 adult patients undergoing orthopedic hand and forearm surgery. The location of the elicited paresthesia prior to deposition of 30 ml of a solution containing 1% mepivacaine, 0.2% tetracaine and 1.200,000 epinephrine was recorded. Twenty minutes later the quality of the block in the distribution of the superior, middle and inferior trunks of the brachial plexus was evaluated. Anesthesia in each of the three trunks was compared with the three sites where the paresthesia was elicited (superior, middle, or inferior trunk). A middle trunk paresthesia was the most successful in producing surgical anesthesia of all three trunks. A superior trunk paresthesia was the paresthesia most often elicited. It resulted in a significantly lower incidence of inferior trunk anesthesia than did a middle or inferior trunk paresthesia. Complications included arterial puncture (25.6%), Horner's syndrome (64.1%), and recurrent laryngeal nerve block (1.3%), with no instances of symptomatic phrenic block or symptomatic pneumothorax.

Adult↗
PubMed1986

Regulation of a human cardiac actin gene introduced into rat L6 myoblasts suggests a defect in their myogenic program.

The rat myogenic cell line L6E9 induces skeletal but not cardiac alpha-actin mRNA upon fusion to form myotubes. However, when a human cardiac alpha-actin gene was introduced into L6E9 myoblasts, differentiation of the cells led to the accumulation of human gene transcripts in parallel with those derived from the endogenous skeletal alpha-actin gene. This result demonstrates that factors which direct rat myogenesis can regulate a muscle gene from another species and that the L6E9 cells may have a defect in their ability to activate endogenous cardiac actin gene expression.

Actins↗
PubMed1975

Anesthetic effects on ventilation in patients with chronic obstructive pulmonary disease.

The effects of 1.0 per cent end-tidal halothane-oxygen anesthesia on spontaneous ventilation, ventilatory deadspace, functional residual capacity (FRC), and alveolar-arterial oxygen difference (A-aD-O-2) were measured in patients with chronic obstructive pulmonary disease and in normal patients of similar age. results obtained were compared with values obtained preoperatively from the same patients. The following were measured: 1) ventilation and ventilatory deadspace, breathing room air and breathing 100 per cent oxygen; 2) functional residual capacity (FRC) and alveolar-arterial oxygen tension difference (A-aD-O-2); 3) forced expiratory volume in 1 second (FEV1.0); 4) ventilatory response to exogenous carbon dioxide. Findings indicated that ventilation is depressed more during halothane anesthesia in patients with emphysema than in normal patients and that the extent of depression is best related to a preoperative measurement of FEV1.0 (P less than 0.001, r = 0.86). The depression in alveolar ventilation results primarily from a reduction in tidal volume. A-aD-O-2 and ventilatory deadspace-to-tidal volume ratio are increaded and FRC decreased with anesthesia in patients with COPD, but the changes are no greater than those found in normal patients.

Anesthesia, Inhalation↗
PubMed1971

Pulmonary artery pressure and alveolar gas exchange in man during acclimatization to 12,470 ft.

Pulmonary hemodynamics and gas exchange were studied in four physicians during 72 hr acclimatization to 12,470 ft. Pulmonary catheters were left in three subjects for 72 hr. Resting mean pulmonary arterial pressure (PAP) rose progressively during the first 24 hr from 10.3 +/-1.0 to 21.1 +/-4.0 torr and remained at this level. During this same 24 hr period cardiac output increased from 7.1 +/-1.4 to 8.4 +/-2.0 liters/min and total pulmonary resistance rose from 122 +/-16 to 209 +/-40 dynes.sec/cm(-5). Excercise at 60 w after 24 hr of hypoxia increased PAP to 28.8 +/-5.1 torr and decreased total pulmonary resistance to 155 +/-25. Shunt fractions were 11 +/-3.8% after 24 hr at altitude and fell to 7 +/-0% after 72 hr. Alveolar to arterial O(2) difference (P(A-a)(O2)) breathing oxygen fell from 116 +/-10.8 to 92 +/-33.3 torr during the same period of acclimatization, whereas dead space to tidal volume ratio (V(D)/V(T)) rose from 33 +/-4.0% to 40 +/-5.3% and P(A-a)(O2) breathing ambient air rose from 8 +/-2.6 to 11 +/-3.0 torr. Inspiratory static lung compliance decreased significantly from a control of 176 +/-8 to 141 +/-8 ml/cm H(2)O after 72 hr of hypoxia. After 4-7 days at altitude, further deterioration in gas exchange was observed after a 5 mile, 1800 ft climb to the summit (14,255 ft) and return. P(A-a)(O2) on air rose from 2.5 +/-2.1 just before starting, to 16.3 +/-2.8 at the summit (rested), and was still 9.0 +/-2.2 several hours after returning. The O(2)-breathing values paralleled these, whereas dead space appeared to fall. We speculate that the hypoxic pulmonary hypertension which develops over 24 hr in some way may be responsible for a reduction of compliance and deterioration in oxygen exchange efficiency, possibly representing a sub-clinical form of pulmonary edema of high altitude. The increased alveolar to arterial O(2) difference induced by hypoxic exercise persists for several hours of hypoxic rest.

Acclimatization↗
PubMed1966

Frostbite.

Explore the source record for details and available documents.

Chlorpromazine↗
PubMedDate not supplied

Effect of oxygen and storage conditions on the metabolic activities of polychlorinated biphenyls dechlorinating microbial granules.

The effect of oxygen and storage conditions on the metabolic activities, measured by volatile fatty acid (VFA) degradation and methane production, and by the dechlorinating activity of methanogenic polychlorinated biphenyl (PCB) granules, were studied. Incubation of the granules in air for different periods did not result in significant inhibition in volatile fatty acid degradation and methane production activities. The inhibitory effect of oxygen increased with increased length of exposure. The overall methanogenic activities, however, recovered after a 10-day incubation period in the absence of oxygen. Oxygen exposure did not cause any significant effect on the dechlorinating activity of the granules tested with a PCB mixture, Aroclor 1254. In 6 months, approximately 80% [based on the concentration (microM) of chlorine removed] of the Aroclor 1254 was dechlorinated even by granules exposed to oxygen for 168 h. Granules stored at room temperature (20 degrees C) appeared to be more active compared to the granules stored at 4 degrees C or -20 degrees C. Similarly, granules stored with a nutrient mixture, containing methanol, glucose and yeast extract showed higher metabolic activities. Our results demonstrate that the effect of oxygen exposure was not significant and was reversible. PCB granules could be stored at room temperature with an auxiliary carbon source in the presence of PCB without significant loss of activity. These properties make methanogenic PCB granules suitable candidates for practical use in PCB dechlorination and biodetoxification.

Anaerobiosis↗
PubMedDate not supplied

Autoregulation of spinal cord blood flow: is the cord a microcosm of the brain?

The autoregulatory capability of regional areas of the brain and spinal cord was demonstrated in 18 rats anesthetized with a continuous infusion of intravenous pentothal. Blood flow was measured by the injection of radioactive microspheres (Co57, Sn113, Ru103, Sc46). Blood flow measurements were made at varying levels of mean arterial pressure (MAP) which was altered by neosynephrine to raise MAP or trimethaphan to lower MAP. Autoregulation of the spinal cord mirrored that of the brain, with an autoregulatory range of 60 to 120 mm Hg for both tissues. Within this range, cerebral blood flow (CBF) was 59.2 +/- 3.2 ml/100 g/min (SEM) and spinal cord blood flow (SCBF) was 61.1 +/- 3.6. There was no significant difference in CBF and SCBF in the autoregulatory range. Autoregulation was also demonstrated regionally in the left cortex, right cortex, brainstem, thalamus, cerebellum, hippocampus and cervical, thoracic and lumbar cord. This data provides a coherent reference point in establishing autoregulatory curves under barbiturate anesthesia. Further investigation of the effects of other anesthetic agents on autoregulation of the spinal cord is needed. It is possible that intraspinal cord compliance, like intracranial compliance, might be adversely affected by the effects of anesthetics on autoregulation.

Anesthesia, Intravenous↗
PubMedDate not supplied

Lidocaine hydrocarbonate is not superior to lidocaine hydrochloride in interscalene brachial plexus block.

To determine the effect of carbonation of lidocaine, a comparison of 1.0% lidocaine hydrochloride (HCl) and 1.1% lidocaine hydrocarbonate (CO2), both with 1:200,000 epinephrine, was made in this study of 50 patients receiving interscalene brachial plexus blocks. Sensory block was determined by the response to pinprick in the C2-T2 dermatomes, while motor block was assessed by the development of paresis and paralysis at the shoulder and hand. The percentage of patients developing analgesia (decreased sensation to pinprick) and anesthesia (total absence of sensation to pinprick) at each dermatome level as well as the percentage of patients developing motor block was not significantly different between the two forms of lidocaine. The initial onset of analgesia [lidocaine HCl, 4.0 +/- 2.4 (SD) minutes; lidocaine CO2, 4.3 +/- 3.8 (SD) minutes] and anesthesia [lidocaine HCl, 10.1 +/- 5.7 (SD) minutes; lidocaine CO2, 7.8 +/- 4.4 (SD) minutes] did not differ significantly between the two groups. At the individual dermatomes, there was no difference in the onset of analgesia except at one dermatome level, C7, which was near the level of local anesthetic injection. Anesthesia onset in each dermatome as well as the onset of motor block did not differ between the two groups. It is concluded that lidocaine CO2 does not offer any significant clinical advantage over lidocaine HCl in interscalene brachial plexus block.

Adult↗
PubMedDate not supplied

Transarterial techniques are not effective for subclavian perivascular block.

Although transarterial techniques have been commonly used for axillary block, results with these techniques have not been previously described for subclavian perivascular block. We studied the efficacy and complications of two types of arterial techniques for subclavian perivascular block. In Group 1 (n = 10), the subclavian perivascular injection was made after withdrawing the needle from the subclavian artery (top of artery), and in Group 2 (n = 8), the injection was made after advancing through the subclavian artery (bottom of artery). The local anesthetic used was lidocaine 1.5% with epinephrine 1:200,000 in a volume determined by the formula [ml = (height in inches divided by 2) + 5]. Both techniques were associated with a low incidence (50% or less) of anesthesia throughout the brachial plexus dermatomes. Sixty percent of patients in Group 1 and 63% of patients in Group 2 required supplemental blocks. In view of the low incidence of anesthesia and the frequent need for supplementation, additional patients were not enrolled in the study. Complications associated with the technique included hematoma (12-20%), recurrent laryngeal nerve block (10-25%), Horner's syndrome (0-20%) and phrenic nerve block (75-80%). Despite the relatively high dose of lidocaine used, serum lidocaine levels remained well below the toxic range.

Aged↗
PubMedDate not supplied

Comparison of the clinical efficacy of three perivascular techniques for axillary brachial plexus block.

BACKGROUND AND OBJECTIVES: This study compared the efficacy of three perivascular techniques of axillary block. METHODS: In group 1, all of the local anesthetic was injected after advancing the needle through the axillary artery (back of artery, n = 20); in group 2, after withdrawing slightly from the artery (front of artery, n = 20); and in group 3, half of the anesthetic was injected after advancing through and half after withdrawing from the axillary artery (half and half, n = 20). The local anesthetic used for the axillary block was 50 ml of 1.5% mepivacaine with epinephrine 1:200,000. RESULTS: The groups did not differ significantly in the incidence of analgesia or anesthesia expected in the median nerve distribution, where there was a significantly lower incidence of anesthesia in the back of the artery group. This group also had a slower onset of anesthesia for the median and the medial antebrachial cutaneous nerves. CONCLUSIONS: There was no significant difference in the number of patients requiring supplementation, with five patients in the back group (25%), three patients in the front group (15%), and one patient in the half and half group (5%) requiring supplementation for the surgical procedure.

Adult↗