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Biomedical subjects

P Rega

Publications and source records attributed to P Rega.

10 recordsLinked to original sources
PubMed1992

Typing and screening of blood from intraosseous access.

STUDY OBJECTIVE: To determine if intramedullary aspirate from intraosseous needle placement can be used as a source for evaluating blood compatibility. DESIGN: A prospective, nonrandomized, crossover study. SETTING/PARTICIPANTS: Patients admitted to the hematology/oncology service undergoing bone marrow aspiration for medical purposes. INTERVENTIONS: Patients had simultaneous samples of bone marrow aspiration from the posterior iliac crest and peripheral venous blood drawn and sent for typing and screening. MEASUREMENTS AND MAIN RESULTS: The paired samples were evaluated for ABO and Rh typing as well as the presence of human leukocyte activity by evaluating the reaction strength between the marrow and venous samples. RESULTS: No differences were seen in the reaction strength between the paired samples in any subjects for ABO and Rh typing (P = .90, yielding beta = .0523). In addition, human leukocyte activity was detected in both the marrow and venous samples in one patient. CONCLUSION: Bone marrow aspirates following intraosseous infusion can be used for accurate and reliable typing and screening of blood.

ABO Blood-Group System↗
PubMed1991

Axonal regeneration from central respiratory neurons of the adult rat into peripheral nerve autografts: effects of graft location within the medulla.

In adult rats, autologous segments of the peroneal nerve were implanted into the medulla oblongata at the level of the obex either on the midline (midline grafts, n = 4), where respiratory axons decussate, or on the left side (lateral grafts, n = 5) in the area of the respiratory cell bodies. Several months after the graft implantation, spontaneous unitary activities (n = 225) were recorded within the grafts and were found to arise from both central respiratory (R, n = 72) and non-respiratory (NR, n = 153) neurons which were giving off regenerated axons along the nerve grafts. The graft reinnervation by respiratory axons was found to be significantly more abundant within the medullary lateral grafts than within the midline grafts. This finding offers further support of the conclusion that the reinnervation of grafts by axons from central neurons is enhanced when the graft is placed proximally to the cell bodies.

Animals↗
PubMed1990

Functional significance of the dorsal respiratory group in adult and newborn rats: in vivo and in vitro studies.

The involvement of the dorsal part of the medulla (the so-called dorsal respiratory group: DRG) in the networks participating in respiratory function was investigated in newborn (in vitro) and adult (in vivo) rats. In the dorsal part of the medulla of the isolated brainstem of newborn rats, no respiratory neurons were found and stimulations or lesions neither modified nor suppressed the respiratory output. On the contrary, similar experiments suggest that sites in the ventral medulla have a fundamental importance for respiration. In adult rats, lesion of the DRG areas by electrocoagulation induced transient changes in respiratory timing, and resulted in a significant decrease in the amplitude of the contralateral phrenic output. These results suggest that the dorsal part of the medulla is not involved in controlling respiratory activity in the newborn rat. In adults, no definite conclusion can be reached, but the functional role of the DRG, if any, is probably restricted.

Action Potentials↗
PubMed1990

Effects of N-methyl-D-aspartate (NMDA) antagonist MK-801 on breathing pattern in rats.

In anaesthetized, bivagotomized and artificially ventilated rats, the respiratory effects of systemic injection of MK-801, a non-competitive N-methyl-D-aspartate antagonist, were studied. In all the experiments (n = 11), the injection increased the inspiratory duration and decreased the expiratory duration. In 4 experiments, the inspiratory duration was drastically lengthened, resulting in an apneustic-like breathing pattern. These results demonstrate that apneusis is difficult but possible to induce in rats and suggest that termination of inspiration is controlled via central mechanisms in which NMDA-like receptors are involved.

Action Potentials↗
PubMed1990

Comparison of serum phenobarbital levels after single versus multiple attempts at intraosseous infusion.

Serum drug levels from a single intraosseous attempt in nontraumatized bone have proven comparable to levels from IV drug infusions. However, in the clinical situation, inexperienced personnel may make multiple intraosseous attempts, which could allow significant extravasation from multiple intramedullary entrance sites. Serum drug levels arising from multiple intraosseous attempts in traumatized bone were compared with those arising from single intraosseous attempts in nontraumatized bone. We administered phenobarbital to 24 dogs randomly divided into single- (11) and multiple-attempt (13) groups. In the multiple-attempt group, we created three intramedullary insertion sites in a linear fashion and infused through only the central site. In the single-attempt group, only a single infusion site was created. Phenobarbital then was infused into the intramedullary space, and central venous phenobarbital samples were collected at one-, three-, six-, and ten-minute intervals. The single-attempt group attained significantly higher serum phenobarbital levels at each interval compared with the multiple-attempt group (P less than .0001). Therefore, to be an effective mode of therapy, it is critical to achieve single-attempt intraosseous needle placement for intraosseous infusion.

Animals↗
PubMed1989

Pneumotaxic centre and apneustic breathing: interspecies differences between rat and cat.

Pontine influences on the breathing pattern were studied in rats using either in vivo experiments in anaesthetized adult animals or in vitro experiments in newborn preparations. In cats, after anaesthesia and bivagotomy, pontine transection has been described as evoking an apneustic pattern of breathing (long sustained inspiratory discharges interrupted by short expiratory pauses). In rats, after anaesthesia, bivagotomy and pontine transection, apneustic patterns of breathing were not observed, either in vivo or in vitro. These results suggest interspecies differences between rat and cat in the pontine influences on the medullary respiratory generator.

Anesthesia, General↗
PubMed1988

Analysis of growth plate abnormalities following intraosseous infusion through the proximal tibial epiphysis in pigs.

Intraosseous infusion has become an increasingly popular technique for vascular access in critically ill or injured children. Continuing acceptance of this procedure by physicians and possibly by prehospital personnel may lead to inadvertent placement through the immature growth plate. In our study, we intentionally penetrated the epiphyseal plate with the intraosseous needle and infused fluids in order to observe what complications, if any, might arise from this procedure. Twenty pigs 3 to 4 weeks old had a bone marrow aspiration needle introduced into the medullary cavity through the tibial epiphysis under fluoroscopic visualization. Sodium bicarbonate at 2 mEq/kg (n = 10) or 0.9 normal saline at 2 mL/kg (n = 10) was infused through the intraosseous needle. Radiographs of the involved growth plates were taken at two months and six months after infusion. No growth disturbances or growth plate abnormalities were detected clinically or radiographically through the rapid growth phase of the porcine tibia. Therefore, we believe that intraosseous infusion is a safe method of alternative vascular access associated with no significant growth defects despite injury to the developing growth plate from placement and infusion.

Animals↗
PubMed1987

A comparative study of intraosseous versus peripheral intravenous infusion of diazepam and phenobarbital in dogs.

Authors of recent literature have made several references to the use of intraosseous infusion in emergency situations. This method has provided a useful route of medication and fluid administration when peripheral IV access has been unsuccessful. Controlled studies on intraosseous infusion have been limited. To more accurately evaluate the effectiveness of this technique, we administered diazepam to 20 dogs randomly assigned to either peripheral IV (n = 10) or tibial intraosseous (n = 10) groups. Intramedullary placement usually was performed within 15 seconds. Central venous diazepam samples were collected at one-, three-, six-, ten-, and 20-minute intervals. Intraosseous infusion achieved and maintained serum diazepam levels comparable to those achieved by IV administration. This study was repeated with phenobarbital using a different set of 20 dogs with samples collected at one-, three-, six-, and ten-minute intervals. Results were similar in that the levels were comparable regardless of the use of intraosseous or IV administration. Complications using this technique have been few. When peripheral IV access is unobtainable, intraosseous infusion has been shown to be an effective and efficient alternative for administering medications and fluids.

Animals↗