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Biomedical subjects

M Abel

Publications and source records attributed to M Abel.

At least 19 recordsLinked to original sources
PubMed1992

Correlation between myocardial ischemia and changes in arterial resistance during coronary artery bypass surgery.

The arterial resistometer provides continuous on-line monitoring of changes in arterial resistance. Resistance index (Ri), which bears a direct relationship to systemic vascular resistance (SVR), is defined by the equation Ri = P'/(dP'/dt), where dP'/dt is the peak dP/dt of the arterial waveform, and P' is the pressure at dP'/dt. In 42 patients with unstable angina, changes in Ri were studied at six periods during aortocoronary bypass surgery before tracheal intubation, during tracheal intubation, leg elevation, presternotomy, sternotomy, and dissection of the internal mammary artery. Thirty-four episodes of ischemia (0.1 mV ST segment changes) were observed in 26 patients. All ischemic episodes were associated with increased Ri (mean increase, 102 +/- 52%). Elevation of the pulmonary capillary wedge pressure correlated with ischemia during the preintubation, intubation, and sternotomy periods, but not in the remaining periods. Changes in arterial pressure and heart rate were not good predictors of ischemia. The prevalence of ST segment changes increased markedly during all periods of anesthesia with increase in Ri (P less than 0.05). Ninety-one percent of ST segment changes were associated with a 25% increase from the baseline Ri. Raising the cutoff point to a greater than or equal to 75% increase in Ri improved the specificity of Ri in ischemia detection from 61% to 92%. An increase of greater than or equal to 75% in Ri occurred in only 8% of cases without ST segment changes. It was found that an increase in Ri as depicted by the arterial resistometer was the best hemodynamic correlate of myocardial ischemia.

Adult↗
PubMed1992

Greater neuromuscular blocking potency of atracurium during hypothermic than during normothermic cardiopulmonary bypass.

Previous studies drew attention to the greater neuromuscular blocking potency of atracurium during, than before or after, hypothermic cardiopulmonary bypass (CPB) while disregarding the periods of normothermic perfusion. We recorded the evoked twitch tension in 15 patients during nitrous oxide/narcotic anesthesia who were undergoing open heart surgery. Atracurium was injected as an initial bolus dose of 460 micrograms/kg. Waning neuromuscular blockade was enhanced by repeat injections of 138 micrograms/kg whenever the twitch tension attained 25% of control. During hypothermic (< 32 degrees C) and normothermic (> 34 degrees C) CPB, the times of onset of the maintenance doses were 57% and 18% longer, respectively, than before CPB (P < 0.05). Maintenance doses of atracurium were required every 24 +/- 4 min (mean +/- SD) before CPB, every 45 +/- 8 min (P < 0.05) during hypothermia, every 22 +/- 3 min during normothermic perfusion, and every 23 +/- 3 min after CPB. In conclusion, the patients' changing demand of atracurium paralleled the changes of temperature rather than the institution and cessation of CPB.

Aged↗
PubMed1991

Response to suxamethonium in a myasthenic patient during remission.

A cumulative dose followed by an infusion was used to determine the dose response to suxamethonium in a patient with diagnosed myasthenia gravis who was in true remission (asymptomatic while receiving no therapy). The ED50 and ED90 values for suxamethonium were 0.08 mg/kg and 0.20 mg/kg, and an infusion rate of 3.2 mg/kg/hour was required to maintain a 90-95% depression of the single twitch response as monitored by integrated electromyography. These values are within the range for normal patients, and we conclude that myasthenic patients during a true remission may not demonstrate resistance to suxamethonium.

Anesthesia↗
PubMed1991

[A computerized database for problem patients in pediatric anesthesia].

A computerized database for use in pediatric anesthesia and in the perioperative care of patients with malformation syndromes and rare diseases is presented. A total of 2200 syndromes are listed, and the database contains helpful data, experience, guidelines and literature references relevant to about 500 rare diseases. The access to the databank, its structure and the probable benefits of the system are explained and discussed.

Anesthesiology↗
PubMed1990

[Brain stem dysfunction in Arnold-Chiari II syndrome].

Among 76 patients suffering from myelomeningocele treated during 1978 to 1987 there were 12 children with brain stem signs as a sequel to Arnold-Chiari II syndrome. In 2 of these patients only stridor was seen, in 4 stridor with attacks of apnoea, in 2 attacks of apnoea with dysphagia, and in 4 children stridor, attacks of apnoea and dysphagia. Hence, it will be necessary to modify the classification given by Charney et al (4) in respect of brain stem patterns of signs according to three grades, since the signs of stridor, apnoea and dysphagia can be combined with each other in different ways. The prognosis is infaust if all 3 signs and hence grade III of brain stem lesions are present. On the whole, 6 out of 12 patients with brain stem signs died. For this reason, a possible Arnold-Chiari malformation should always be considered if stridor is observed, and, if necessary, early decompression treatment by means of a shunt revision should be performed.

Arnold-Chiari Malformation↗
PubMed1990

[Postoperative apnea--a special risk for former preterm infants].

Infants who had been originally preterm are subject to a particularly high risk after surgical interventions involving anaesthesia, due to a tendency to experience disturbance of respiratory regulation. Of a total of 130 originally preterm infants who had to undergo anaesthesia for so-called minor surgery, respiratory anomalies were seen in 66%, 48%, 10% and 7% of the infants in the age groups of 40, 50, 60 and 80 weeks after conception, respectively. Therapeutic measures were necessary only in patients up to a post-conceptional age of 40 to 50 weeks, the respective incidences being 24% and 20%. To minimise the risk of postoperative early and late apnea in ex-preterm infants, the following measures are presented and discussed: elective surgical interventions should be postponed until after the 50th post-conceptional week; in individual cases, indication for perioperative theophylline/caffeine treatment can be made more precise by means of preoperative ECG-coupled impedance pneumography; all measures of preoperative preparation, choice of anaesthetics and of adjuvant drugs, as well as perioperative infusion therapy, must be taken in full consideration of all neonatal previous diseases; patients up to the 50th week after conception require intensive-care monitoring primary and post-anaesthesiologically for at least 24 hours. In all patients who were older than 50 week after conception, two hours of intensive-care monitoring in the so-called "recovery from anaesthesia room" followed by 12 hours of ECG and apnea monitoring proved sufficient; in ex-preterm infants, even minor surgery should be performed on an in-patient basis only, to ensure proper monitoring.

Anesthesia↗
PubMed1988

[An unusual cause of postoperative pharyngeal obstruction].

In neonates, heating technics are often used to maintain body temperature during surgery. In these patients temperature monitoring is done by special thermocatheters, which are protected by single use covers. A case report of postoperative pharyngeal obstruction from such a device is presented. Severe dyspnea was caused by a part of the thermometer cover after removal of the thermocatheter and extubation of the patient.

Body Temperature↗
PubMed1987

[Supraventricular tachycardia following POR 8 (ornipressin)--administration in an infant].

Prevention of surgical blood loss by local vasoconstrictors is a useful technique in necrectomy after severe burns. It allows excision of large areas and grafting without severe side effects even in very young patients. Nevertheless, we have observed an episode of supraventricular tachycardia in an 11-month-old patient after Ornipressin during wound excision and grafting. Possibilities for prevention and treatment are discussed.

Anesthesia↗
PubMed1987

[Medication and monitoring in young pediatric patients in NMR (nuclear magnetic resonance) studies].

Nuclear magnetic resonance (NMR) is a recently developed, noninvasive technique of increasing importance in pediatric diagnosis. In newborns and very young infants problems may arise with regard to adequate sedation and sufficient patient monitoring during NMR imaging. In 44 of 46 young pediatric patients sedation with oral promazine or rectal diazepam/intravenous ketamine provided good immobilization during NMR scanning. In two patients an additional drug was necessary in order to successfully complete the NMR procedure. Satisfactory monitoring of patients' respiratory motions was obtained by means of a simple optical system. Good cardiovascular monitoring was made possible by lengthening the rubber tubing of a blood pressure cuff. No complications were observed during the NMR-procedures.

Anesthesia↗
PubMed1986

Nutrition of cruciate ligament reconstruction by diffusion. Collagen synthesis studied in rabbits.

The reconstructed anterior cruciate ligament was studied in the rabbit using the medial third of the patellar tendon. Tritiated proline, 100 microCi/kg body weight, was injected intra-articularly to insure detection of the metabolic conversion product 3H-hydroxyproline in the avascular graft. During the immediate postoperative period, nutrients were found to derive from the synovial fluid through a process of diffusion, demonstrating that synovial nutrition occurs prior to revascularization of the graft.

Animals↗
PubMed1986

Diagnostic procedures leading to successful separation of xipho-omphalopagus twins.

Xipho-omphalopagus twins with a pericardial bridge, extended liver tissue union and considerable intestinal herniation from one abdominal cavity to the other were separated successfully at the age of three months. Special diagnostic procedures including cardiac and abdominal sonography, catheterism of the umbilical vein with portal angiography, radionucleotide liver and bile duct imaging and separate oral glucose tolerance tests provided important information for perioperative and surgical patient management. Relevant items for determination of the favourable data and method of surgery are discussed.

Adolescent↗
PubMed1986

[Intravascular monitoring by axillary artery cannulation in infants].

In patients with respiratory failure and shock serial arterial blood analyses are important to calculate adequate respiratory therapy. During circulatory insufficiency punction of a radial artery can be difficult or impossible, especially in very young patients. The case report of a 9-month old female infant with septic shock and Waterhouse-Friderichsen's syndrome illustrates these problems and is helpful to describe an alternative technique. Percutaneous axillary arterial catheterization with a disposable venous cannula proved to be a simple and quick method to obtain the possibility of arterial monitoring in very young patients with severe hypotension.

Acid-Base Equilibrium↗
PubMed1986

[Primary management of newborn infants with respiratory failure due to a congenital defect of the diaphragm].

The authors report on 36 premature and term infants with congenital defects of the diaphragm, including 17 patients who developed a severe respiratory insufficiency either immediately after birth or during the first 30 minutes of life. The overall mortality rate was 64%; the results of treatment were marked by a particularly high mortality rate among the patients with early respiratory insufficiency: out of 17 patients, 12 died. The evaluation of the courses confirmed that adequate preoperative primary care is of major prognostic importance in patients with early respiratory insufficiency. On the basis of personal experience the authors have formulated the following recommendations for improving diagnosis and therapy at this stage of care: greater use of sonography examination methods for antepartal diagnosis of congenital defects of the diaphragm, making it possible to treat the corresponding high-risk pregnancies at an early stage in clinics equipped for neonatologic and pediatric surgical treatment; early intubation respiration with a ventilation technique which does not overstrain the patient, in newborns with abnormal respiration and suspected congenital defects of the diaphragm; the great diagnostic importance of plain radiographs of the thorax and abdomen; neonatologic and intensive medical stabilization treatment in patients with severely suppressed metabolism prior to the anesthesiologic and surgical stress of closure of the diaphragm defect.

Critical Care↗
PubMed1985

[Emergency medicine and anesthesiology aspects of neurofibromatosis in childhood].

In infancy mediastinal and major airway associated tumours can cause respiratory emergency situations requiring resuscitation and special anaesthetic management. The case report of an infant with a cervicothoracal neurofibroma and resulting acute respiratory distress underlines these problems. In anaesthetic and surgical procedures these patients can experience respiratory difficulties with severe consequences. Preoperative possibilities to evaluate and reduce these risks are presented and discussed.

Anesthesia, General↗
PubMed1985

Rib perichondrial grafts for the repair of full-thickness articular-cartilage defects. A morphological and biochemical study in rabbits.

The purpose of this study was to investigate the use of perichondrial grafts in articular cartilage defects and to characterize the newly formed cartilage. In a rabbit model, rib perichondrium was used to repair full-thickness defects in the femoral condyle. The quality of repair was then evaluated histologically and biochemically at six and twelve weeks after grafting. Unacceptable results were obtained in 50 per cent of the rabbits. These failures were due to condylar fracture in 20 per cent, failure of graft attachment in 20 per cent, and infection in 10 per cent. The technique of grafting must be improved to increase the percentage of successful grafts in which neocartilage with a relatively normal chemical composition fills the articular cartilage defect. Successful grafts proliferate to fill the full-thickness defect with neocartilage, which has biochemical characteristics that are similar to those of hyaline cartilage.

Animals↗
PubMed1985

[The validity of using autologous placental blood in transfusion medicine].

Resuscitation of the newborn with severe anemia and shock requires rapid expansion of the circulatory volume. This study was done to answer the question whether an infant's autologous placental blood can be recommended for this purpose. In 20 term newborns we obtained immediately after placenta delivery placental blood for bacteriologic, biochemical, hematologic and hemostaseologic investigations by a special placental vein cannulation technique. Besides other coagulation tests resonancethrombography was done and proved to be a simple, quick and reliable method to study coagulability of the placental blood samples. Together with the well-known advantages of autologous blood use the results of this study encourage us to consider autologous placental blood valuable in situations of urgent neonatal volume resuscitation.

Anemia↗