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Biomedical subjects

P A Scheck

Publications and source records attributed to P A Scheck.

12 recordsLinked to original sources
PubMed1994

Forces applied during laryngoscopy in children. Are volatile anaesthetics essential for suxamethonium induced muscle rigidity?

Increased masticatory muscle tone after administration of suxamethonium has been demonstrated in children when combined with volatile anaesthetics. Whether volatiles are a prerequisite for this phenomenon is not known. In this study upper airway muscle tone, including the tone of the masticatory muscles, was determined in 54 children (age range 2-15 years), anaesthetized with propofol, fentanyl and nitrous oxide and avoiding any use of volatiles. The children were either relaxed with suxamethonium (n = 26) or vecuronium (n = 28). The forces applied during laryngoscopy were used to quantify upper airway muscle tone and were significantly greater in the suxamethonium group than in the vecuronium group: maximally applied force was 25 N versus 21 N (P = 0.008), and mean applied force was 16 N versus 13 N (P = 0.006), respectively. The results of this study indicate that upper airway muscle tone increases after administration of suxamethonium in children independent of the presence of volatile anaesthetics. Moreover, increased muscle tone had no effect on the difficulty of laryngoscopy or the intubation conditions. Increased masseter muscle rigidity after suxamethonium could be due to the very unique characteristics of this muscle.

Adolescent↗
PubMed1992

Measurement of forces during laryngoscopy.

The forces transmitted by the laryngoscope blade onto the base of the tongue are assumed to be a major cardiovascular stimulus. This study investigates the various forces applied onto a Macintosh laryngoscope during laryngoscopy. The forces acting along the axis of the handle are described, as well as the forces exerted by the anaesthetist to prevent the laryngoscope from turning. Based on a relatively simple technique, a modified laryngoscope has been designed to measure these forces. Four different laryngoscopic parameters are determined: (1) the duration of laryngoscopy, (2) the maximally applied force, (3) the mean force and (4) the integral of the force over the time (area under the curve). The force measurements of 49 anatomically normal patients undergoing uncomplicated intubation are included in the study. The duration of laryngoscopy was 16.3s (SD 11.8), the applied peak force was 35N (SD 12) and mean force necessary was 20N (SD 6) while the force-time integral was 324N (SD 194).

Adult↗
PubMed1992

Forces applied during laryngoscopy and their relationship with patient characteristics. Influence of height, weight, age, sex and presence of maxillary incisors.

The relationships between patients' height, weight, age, body mass index, gender and presence of maxillary incisors and a series of laryngoscopic factors have been studied. These included the duration of laryngoscopy, maximally applied force, mean applied force and the integral of force over time. There was a positive correlation between height and weight and laryngoscopic factors. Sex and age also showed a positive correlation but these could be explained by differences in height, weight and the presence of maxillary incisors. This latter factor was the dominant patient characteristic influencing the measured laryngoscopic factors. Use of these laryngoscopic factors as a measure of difficulty of laryngoscopy is discussed.

Adolescent↗
PubMed1992

Cardiovascular effects of forces applied during laryngoscopy. The importance of tracheal intubation.

The relationship between the forces applied during laryngoscopy and cardiovascular changes were studied in patients undergoing laryngoscopy with or without intubation. This enabled us to differentiate between the cardiovascular effects of laryngoscopy and the effects of tracheal intubation. The forces applied during laryngoscopy were only weakly related to the cardiovascular changes, whereas tracheal intubation had a major influence. The many difficulties encountered in interpreting results from these studies are discussed. It is concluded that tracheal intubation causes more cardiovascular changes than laryngoscopy in routine uncomplicated procedures.

Adolescent↗
PubMed1984

Peroral endoscopies using intravenous anesthesia and high-frequency ventilation.

Peroral endoscopies and elective or emergency surgery must often be performed in the airway of patients in poor physical condition. This retrospective review of 600 patients undergoing various surgical procedures found that 194 were ASA physical status groups III or IV, with various abnormalities affecting the cardiorespiratory or central and peripheral nervous systems. These patients received iv anesthesia using short-acting drugs, to guarantee rapid postoperative recovery. All were intraoperatively ventilated with either high-frequency positive-pressure ventilation or high-frequency jet ventilation. Both techniques proved effective, even in patients with upper airway obstruction. In combination with CO2 laser removal of tumors of the glottic region, high-frequency ventilation may prevent the need for emergency tracheotomies.

Adult↗
PubMed1984

High frequency ventilation in laser surgery of the larynx.

For endolaryngeal laser surgery an anaesthetic technique is required which provides the surgeon good access to the larynx. High frequency ventilation of the lungs using a FG 14 insufflation catheter covered by aluminium foil has proved to give a nearly optimal condition for the surgeon, while the fully paralyzed patient is very well ventilated. This has been used in more than 1000 patients, 200 of them have been treated by the laser beam in the airway. A method of total intravenous anaesthesia is described using short acting drugs. This way early awakening after surgery in the airways prevents aspiration of blood or debris into the lungs.

Catheterization↗
PubMed1984

Etomidate suppresses adrenocortical function by inhibition of 11 beta-hydroxylation.

We studied the effect of short term infusion of the imidazole-derived anesthetic agent etomidate on plasma concentrations of ACTH, cortisol, and the cortisol-precursors 11-desoxycortisol and 17-hydroxyprogesterone. During the infusion of etomidate, a significant increase in the peripheral concentration of ACTH occurred, while plasma cortisol concentrations decreased. After the end of the infusion, cortisol concentrations further decreased, while the concentrations of desoxycortisol and 17-hydroxyprogesterone increased. Furthermore, in in vitro experiments with isolated rat pituitary and adrenal cells, etomidate did not affect corticotropin-releasing hormone-induced ACTH secretion from pituitary cells, whereas ACTH-stimulated corticosterone secretion from adrenal cells was inhibited by addition of etomidate in concentrations which occur in plasma during and after infusion of the drug. These results lead to the conclusion that etomidate inhibits adrenal 11 beta-hydroxylation.

17-alpha-Hydroxyprogesterone↗
PubMed1981

A pharyngeal pack fixed on to the tracheal tube.

In 205 patients undergoing surgery of the nose, throat of dental surgery, a gauze pack was used fixed into the tracheal tube, remaining during surgery above the vocal cords. Advantages in adults as well as children are discussed: laryngoscopy has to be performed only once, a free operating field is secured for the surgeon in that throat, the tube cannot be inserted too far into the trachea and the pack cannot be forgotten in the pharynx. The only disadvantage noticed so far was that in about 10% of the patients intubation was somewhat more difficult for the less experience anaesthetist.

Adult↗