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Biomedical subjects

R R Schultetus

Publications and source records attributed to R R Schultetus.

10 recordsLinked to original sources
PubMed1990

Lower esophageal sphincter integrity is maintained during succinylcholine-induced fasciculations in dogs with "full" stomachs.

During succinylcholine-induced muscle fasciculations, gastroesophageal barrier pressure in fasted adult dogs (n = 10) was compared by esophageal manometry with that in the same dogs with full stomachs. After fasting, fasciculations did not increase significantly either mean intragastric pressure (4.7 +/- 1.3 mm Hg before; 5.2 +/- 1.7 mm Hg during) or lower esophageal sphincter pressure (35.4 +/- 21.4 mm Hg before; 40.6 +/- 17.5 mm Hg during). Filling the dogs' stomachs with 300 mL of saline significantly increased both mean intragastric pressure (from 3.8 +/- 2.2 to 7.4 +/- 1.4 mm Hg) and mean lower esophageal sphincter pressure (from 20.2 +/- 6.8 to 28.6 +/- 14.8 mm Hg). Fasciculations did not produce a further increase in either mean intragastric or mean lower esophageal sphincter pressure. Most importantly, in all animals, under all conditions, gastroesophageal barrier pressure remained positive (range, 6.0-65.5 mm Hg) and therefore served as a barrier to passive regurgitation.

Animals↗
PubMed1987

Continuous neonatal evaluation in the delivery room by pulse oximetry.

The pulse oximeter, a noninvasive and continuous monitor of arterial oxygenation that is reliable in adults, children, and infants, was evaluated for use in neonates in the delivery suite. One hundred newborn infants, weighing 850 to 5,230 g each, delivered vaginally or by cesarean section with general or epidural anesthesia were studied. After delivery, each infant was placed in a radiant warmer, and a pulse oximetry probe was placed on the right hand. Hemoglobin saturation was then recorded for 15 minutes. Initial pulse oximetry values were obtained in less than one minute after cord clamping in 43% of infants, less than two minutes in 81%, and less than three minutes in 98%. Average arterial oxygen saturation was 59% at 1 minute (43 infants), 68% at 2 minutes (81), 82% at 5 minutes (98), and 90% at 15 minutes (91). Oxygen saturation was less than 30% in 12 neonates and less than 50% in 26 neonates at some time during the 15-minute monitoring period. Oxygen saturation did not differ significantly between neonates delivered vaginally or by cesarean section, regardless of the presence or type of anesthetic used. Arterial oxygen saturation measured by pulse oximetry showed a statistically significant relationship when compared with the traditional Apgar scoring system. Pulse oximetry was found to be very useful in objectively judging the adequacy of resuscitative efforts, as well as in identifying children who had marked arterial desaturation during the early neonatal period.

Humans↗
PubMed1987

The effect of the Bain circuit on gas exchange.

This is an experimental and theoretical analysis of the Mapleson D (Bain) circuit. A bench model was used to determine the effects of breathing rate, tidal volume, and fresh gas flow on the simulated alveolar gas composition when a commercial Bain breathing circuit is used. In addition, an effort was made to derive mathematical equations that describe the CO2-profile in the expiratory limb of the Bain circuit, the amount of CO2 rebreathed, and the effect of this rebreathing on the alveolar gas composition. Data obtained with the bench model and with the equations were compared to data from the literature. The effect of the Bain circuit on gas exchange was compared to that of an equivalent dead space.

Anesthesiology↗
PubMed1987

A comparison of d-tubocurarine pretreatment and no pretreatment in obstetric patients.

The effect of pretreatment with d-tubocurarine on the incidences of succinylcholine-induced fasciculations and post-operative muscle pain, and the time to onset of and 50% recovery from neuromuscular blockade were studied in 75 obstetric patients. Thirty women with term pregnancies undergoing general anesthesia for elective cesarean section or cesarean section indicated by cephalopelvic disproportion were randomly assigned to two groups. Group C-1 patients received 0.05 mg/kg of d-tubocurarine followed by 1.5 mg/kg of succinylcholine, and group C-2 patients received 1.5 mg/kg of succinylcholine, and group C-2 patients received 1 ml of normal saline followed by 1 mg/kg of succinylcholine. An investigator, unaware of the relaxant regimen used, judged severity of fasciculations and postoperative muscle pain and measured times to onset of and 50% recovery from neuromuscular blockade. This same study design was followed in a group of 30 women undergoing tubal ligation 1 day after vaginal delivery (groups T-1 and T-2). The incidence of both fasciculations and postoperative muscle pain was low and was not significantly different between pretreated and nonpretreated groups. Time to 100% twitch depression was also not significantly different between pretreated and nonpretreated groups. Time to 50% recovery from neuromuscular blockade was significantly longer in both nonpretreated groups (C-2 and T-2). An additional group of 15 patients undergoing general anesthesia for cesarean section using 0.7 mg/kg of succinylcholine without d-tubocurarine pretreatment was studied (group C-3). This smaller dose of succinylcholine produced onset and 50% recovery times similar to the group pretreated with d-tubocurarine (group C-1).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

Wakefulness during cesarean section after anesthetic induction with ketamine, thiopental, or ketamine and thiopental combined.

Thirty-six pregnant women (ASA class I or II) at term who underwent general anesthesia and cesarean section received either ketamine, 1 mg/kg (n = 12); thiopental, 4 mg/kg (n = 13); or a combination of ketamine, 0.5 mg/kg, and thiopental, 2 mg/kg (n = 11). A blood pressure cuff inflated to 250 mm Hg isolated one arm from the effects of succinylcholine so that awareness during anesthesia could be assessed by asking the patient to move her hand. Although only one patient receiving ketamine responded to commands during anesthesia, 46% of patients receiving either thiopental or the combination responded to commands intraoperatively. No patient hallucinated, the incidence of dreams was low (11%), and no postoperative dysphoria was noted. Three patients (8%) had postoperative recall of intraoperative awareness; one had received thiopental and two the combination. Maternal intraoperative cardiovascular responses among the groups were similar, as were umbilical blood gas values, newborn Apgar scores, and neonatal neurobehavioral test scores at 4 and 24 hr. Ketamine more effectively blocked maternal responsiveness to commands and strong stimuli during the first few minutes after anesthetic induction for cesarean section than did thiopental or a combination of thiopental and ketamine, each at a lower dose.

Adult↗
PubMed1985

Haemodynamic effects of ketamine and thiopentone during anaesthetic induction for caesarean section.

Ketamine (1 mg . kg-1) or thiopentone (4 mg . kg-1) was used to induce anaesthesia for Caesarean section in 62 normotensive patients. During induction of anaesthesia and before laryngoscopy, blood pressure did not change in either group (preinduction systolic blood pressure, 131 mmHg, and diastolic blood pressure, 75 mmHg). When laryngoscopy and intubation were performed, mean blood pressures of both patient groups increased 20-30 per cent. With ketamine (n = 30) heart rate was unchanged from the preinduction rate of 85 beats/min before laryngoscopy and increased significantly by 15 per cent during laryngoscopy and intubation. With thiopentone (n = 32), heart rate increased significantly to 20 per cent above the preinduction rate of 87 beats/min during induction and increased further (to 35 per cent above the preinduction rate) during laryngoscopy and intubation. The average maximal rate-pressure product calculated for the thiopentone group was over 18,000, which was significantly higher than the 15,000 calculated for the ketamine group. Neonatal outcome as assessed by Apgar score and umbilical blood gas analysis was good and did not differ significantly between groups.

Blood Pressure↗