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Biomedical subjects

F J Frei

Publications and source records attributed to F J Frei.

At least 37 records · Page 2Linked to original sources
PubMed1997

Haemodynamic responses to sevoflurane compared with halothane during inhalational induction in children.

We studied the haemodynamic changes during induction of anaesthesia in 50 ASA I and II children (1-12 yrs) undergoing minor elective surgery. The patients were randomly divided into two groups to receive either halothane (n = 25) or sevoflurane (n = 25) in a mixture of O2 and N2O (40:60) for mask induction of anaesthesia. Induction of anaesthesia was performed with an overpressure technique by administering rapid increases of gas concentrations, in increments of 1% up to 7% for sevoflurane and of 0.5% up to 3% for halothane. Induction was smooth and rapid in both groups but characterized by increases in heart rate and systolic blood pressure up to 20% especially in the sevoflurane group (P < 0.05); these increases in the latter group were significant compared with baseline and the halothane group (P < 0.05). No serious complications were observed. The authors conclude that more children experienced heart rate and blood pressure increases during the early stage of inhalational induction with sevoflurane compared with halothane.

Analysis of Variance↗
PubMed1997

Teaching the use of fiberoptic intubation for children older than two years of age.

UNLABELLED: In 144 anesthetized children aged 2-9 yrs, the safety and feasibility of orotracheal fiberoptic intubation, with and without an airway endoscopy mask, were assessed and compared with laryngoscopic intubation. Eight anesthesia residents with experience in adult fiberoptic intubation, but who were beginners in pediatric anesthesia, participated in this study. In a randomized fashion, each resident intubated 18 children (6 in each group). The time (mean +/- SD) to achieve successful intubation was different for laryngoscopic and fiberoptic intubation (34 +/- 17 s and 80 +/- 39 s, respectively; P < 0.001). The use of the airway endoscopy mask further prolonged fiberoptic intubation (167 +/- 121 s, P < 0.001). Spo2 values remained >95% in all patients during conventional laryngoscopy and fiberoptic laryngoscopy with a mask, whereas Spo2 decreased below 95% in 2 of the 48 patients during fiberoptic intubation without a mask. Both patients promptly recovered during ventilation via a face mask. We conclude that teaching the use of fiberoptic intubation in healthy, anesthetized children aged 2-9 yrs is safe and feasible. IMPLICATIONS: Fiberoptic intubation is a valuable technique of airway management. We studied the feasibility and safety of a training program that could be used for children more than 2 yrs old. This study demonstrates that fiberoptic intubation can be effectively practiced in pediatric patients without increased risk of side effects.

Anesthesiology↗
PubMed1997

Minimum alveolar concentration for halothane in children with cerebral palsy and severe mental retardation.

Children with cerebral palsy and severe mental retardation who present for operation may require lower concentrations of inhalational anaesthetics than healthy children. The minimum alveolar concentration (MAC) for halothane was measured in 36 children and adolescents, aged 4-18 years, who underwent orthopaedic surgery. The control group consisted of 12 healthy children (group 1). Children with cerebral palsy and severe mental retardation were allocated to one of two groups: those taking chronic anticonvulsant medication (group 2) (n = 12) and those who did not take any drugs (group 3) (n = 12). The mean (SEM) MAC value for halothane (expressed in volume per cent) was 0.90 (0.02) for healthy children. Children with cerebral palsy had significantly lower MAC values whether they took anticonvulsant drugs or not (0.62 (0.03) and 0.71 (0.10), respectively).

Adolescent↗
PubMed1995

The airway endoscopy mask: useful device for fibreoptic evaluation and intubation of the paediatric airway.

A mask is presented which allows the administration of 100% oxygen, inhalational anaesthetics, continuous positive airway pressure and intermittent positive pressure ventilation during diagnostic airway endoscopy and difficult intubation with a fibreoptic bronchoscope in paediatric patients. The mask is particularly useful in small or critically ill patients. It may also have its place in teaching situations.

Adolescent↗
PubMed1994

Are laboratory values in bone marrow aspirate predictable for venous blood in paediatric patients?

In an emergency situation, early laboratory results are important, but often difficult to obtain. If venous access cannot be established, the intraosseous route may be used as an alternative. This study investigated the predictive value of bone marrow aspirate in performing laboratory studies. Thirty children underwent general anaesthesia for bone marrow aspiration (iliac crest) for oncologic or haematologic reasons. The aspirate and a peripheral venous blood sample, which was obtained simultaneously, were subjected to different laboratory tests and the results were compared by means of confidence interval analyses of the individual ratios of venous/bone marrow values. Based on these analyses, a high predictability of bone marrow values were found for haemoglobin, sodium, chloride, glucose, bilirubin, urea, creatinine, pH, and standard bicarbonate. Moderate, but clinically useful predictability was found for haematocrit, potassium, and total protein, while bone marrow values of alkaline phosphatase, aspartate aminotransferase, alanine aminotransferase, PCO2, PO2, thrombocytes and leukocytes were systematically different from values in venous blood. Our data suggest that the intraosseous route is not only an important emergency alternative to intravenous access for administering fluids and drugs but may also serve as a reliable alternative for obtaining initial diagnostic laboratory studies when intravascular access is not obtainable.

Analysis of Variance↗
PubMed1994

Effects of ondansetron in the prevention of postoperative nausea and vomiting in children.

BACKGROUND: Postoperative nausea and vomiting (PONV) is a commonly observed adverse effect of general anesthesia. Recently, ondansetron, a new serotonin3 (5-hydroxytryptamine3) receptor antagonist was shown to be effective in the prophylaxis and prevention of chemotherapy-induced nausea and vomiting in children and adults as well as of PONV in adults. The aim of the current study was to evaluate the capacity of ondansetron to prevent PONV in pediatric patients. METHODS: Two hundred children (132 boys and 68 girls) 2-10 yr of age received general inhalational anesthesia for surgical procedures (the extremities; ear, nose, and throat; inguinal hernia and phimosis; and dentistry) of an expected duration of less than 90 min. This study was divided into two phases: prophylaxis and rescue treatment. For prophylaxis, patients were randomly assigned to two groups: one group received an intravenous injection of 0.1 mg/kg ondansetron, and the other group received a placebo before surgical incision under double-blind conditions. For rescue treatment, only placebo patients were included; as a rescue medication they received an intravenous injection of 0.1 mg/kg ondansetron or 0.02 mg/kg droperidol according to a prestudy randomization under double-blind conditions. Incidence and severity of PONV (PONV score 0 = no nausea and no retching; 1 = complaining of sickness and retching; 2 = vomiting one or two time in 30 min; 3 = vomiting more than two times in 30 min) was recorded over a 4-h period in the postanesthesia care unit. Within 72 h of the procedure, a follow-up nurse interviewed the parents for late-onset nausea in the children. RESULTS: With regard to prophylaxis, 10% of patients receiving ondansetron had PONV during the 4-h observation period versus 40% of those receiving placebo (P < 0.001). The incidence of vomiting alone (PONV score > or = 2) was 5% and 25%, respectively (P < 0.001). There were no significant differences between ondansetron and droperidol in the treatment of PONV. However, at the end of the 4-h period, ondansetron patients were less sedated than were patients who had received droperidol (P < 0.01). Interviews with parents could be performed for 143 of 200 children (76 ondansetron and 67 placebo). Twenty-four children (15 ondansetron and 9 placebo) showed late-onset PONV after the 4-h observation period but within 24 h of the procedure (19.7% vs. 13.4%; P not significant). CONCLUSIONS: Ondansetron is effective in the prevention of PONV in pediatric patients for the first 4 h after general anesthesia. Lower sedation scores with ondansetron compared with droperidol may be an advantage, especially in ambulatory surgery. However, the incidence of late-onset PONV (> 4-24 h) was not influenced by prophylactic treatment with one dose of ondansetron preoperatively.

Anesthesia, General↗
PubMed1992

[Neonatal resuscitation in the delivery room. What role does the anesthetist play?].

Neonatal resuscitation in the delivery room of small obstetric units is problematic because of the lack of on-site personnel with adequate training and experience. In large university hospitals this task is usually fulfilled by neonatologists who are present 24 h/day. However, in medium-sized and small obstetric units neonatal resuscitation is performed by a variety of professionals: paediatricians, obstetricians, anaesthetists, midwives, nurses, and nurse anaesthetists. The degree of responsibility and involvement of the anaesthesia specialist in the resuscitation of the newborn in Switzerland is unknown, and therefore an investigation was conducted. METHOD. After a telephone inquiry at all the hospitals in Switzerland, a total of 175 obstetric units were identified. A questionnaire with items regarding organisation, responsibilities, and the extent of involvement of the anaesthesia department of the particular hospital was sent to each of the appropriate anaesthetists. RESULTS. Of the 175 questionnaires, 163 (93%) were returned; 14 could not be analysed (5 were sent to hospitals where there was in fact no obstetric unit and 9 were sent to anaesthetists who shared responsibilities for one unit). In 1988, 76,505 babies were born in Switzerland; two-thirds of these were delivered in hospitals with an annual birth rate of less than 600 births per year. Of the 149 questionnaires that were eligible for further analysis, 118 (79%) documented participation of the anaesthetic team in the resuscitation of the newborn. However, only 22% of these departments had an official contract with the hospital administration. Ninety-nine per cent of all responders agreed that every anaesthetist should have the knowledge--both theoretical and practical--to resuscitate a newborn infant. However, reservations were expressed on how to acquire and how to maintain this competence. The initial evaluation of the newborn was done by an anaesthetist in 3% (2250/76,505) of all deliveries in Switzerland in 1988; 1.2% (882/76,505) of these babies needed bag-and-mask ventilation and in 0.4% (308/76,505) endotracheal intubation was performed by the anaesthetist. Proceeding on the assumption that 5% of all newborns need some sort of resuscitation immediately after birth, it is estimated that in 1988 approximately one-third of resuscitations were performed by anaesthetists. It is therefore concluded that anaesthetists play an important role in the resuscitation of newborns in Switzerland.

Anesthesiology↗
PubMed1991

Flexible laryngoscopy in neonates and infants: insertion through a median opening in the face mask.

The most common reasons for laryngoscopy in newborns and infants are inspiratory stridor and/or dyspnea. With the help of flexible endoscopes, especially with instruments of diminished diameter, laryngoscopy can be carried out even in premature newborns. We report on a technique of flexible laryngoscopy without the need for restraint and with improved safety. A modified face mask is used for endoscopy. An additional hole is made into the mask with a 4.5 mm drill. It is located in the midline just above the nostrils, about 2.5 cm above the ventilation opening. The flexible endoscope is passed into the nose and pharynx with ease. It does not interfere with the anesthetist's ventilation by the mask. In inhalation anesthesia with halothane, 100% oxygen is supplied. The larynx remains in its physiological position. The head is not retroflexed, and the tongue is not supported by an endoscope as in direct laryngoscopy. No muscle relaxation is used, and muscular activity of the larynx can be observed during spontaneous and assisted ventilation.

Anesthesia, Inhalation↗
PubMed1991

Is the end-tidal partial pressure of isoflurane a good predictor of its arterial partial pressure?

End-tidal partial pressure of isoflurane (PE'iso) may be used as a measure of anaesthetic depth. During uptake, an arterial partial pressure (Paiso) which is considerably less than PE'iso (Paiso/PE'iso much less than 1) leads to underestimation of depth of anaesthesia and, during elimination, PE'iso/Paiso much less than 1 will lead to an overestimation of anaesthetic depth. We measured Paiso/PE'iso during a 60-min uptake period of 1% isoflurane and PE'iso/Paiso during the subsequent 60-min elimination period in 26 patients (age 13-88 yr, ASA I-III) undergoing various surgical procedures. After 15 min of isoflurane uptake, Paiso/PE'iso of 26 patients was mean 0.78 (SD 0.10) and this increased only marginally at 60 min (0.79 (0.09)), whereas during elimination, PE'iso/Paiso was in the range 0.79 (0.14)-0.83 (0.11). Predictability of Paiso in a given patient is hindered by the high SD of Paiso/PE'iso and PE'iso/Paiso, but it may be improved by taking into account age, ASA physical status category, vital capacity, inspired minus end-tidal isoflurane partial pressure and arterial minus end-tidal carbon dioxide partial pressure during uptake; and obesity, end-tidal isoflurane partial pressure and arterial minus end-tidal carbon dioxide partial pressure during elimination. However, even with multiple regression analysis (to account for the various possible variables), clinically useful prediction of Paiso/PE'iso and PE'iso/Paiso in a particular patient is not possible (residual SD 0.084 and 0.113, respectively).

Adolescent↗
PubMed1990

[The arterial-end tidal CO2 partial pressure difference during anesthesia].

Arterial CO2 partial pressure (PaCO2) can be continuously and noninvasively estimated by monitoring end-tidal CO2 partial pressure (PetCO2). However, the difference between the two (P(a-et)CO2) may vary considerably between patients. In 26 patients undergoing general anesthesia for various surgical procedures, P(a-et)CO2 was measured. We tested the hypothesis that certain clinical characteristics are associated with higher P(a-et)CO2 values in a given patient. In addition, we tested the hypothesis that P(a-et)CO2 remains constant during anesthesia by comparing the mean of eight P(a-et)CO2 values, which were measured at 15-min intervals, with the initial (P(a-et)CO2 value. Impaired lung function, defined as a lung score above 6, age above 50 years, and overweight (defined as greater than 120% of ideal body weight) were associated with increased P(a-et)CO2 (mean +/- SD: 6.27 +/- 1.85; 5.27 +/- 2.11; and 6.19 +/- 1.95 mmHg respectively) when compared to normal lung function (lung score less than or equal to 6), age below 50 years, and normal weight (less than 120% of ideal body weight, 3.87 +/- 2.31; 3.55 +/- 2.58; and 3.77 +/- 2.25 respectively). Although these differences are statistically significant, the standard deviations are large and do not allow the prediction of P(a-et)CO2 in a given patient. Initial P(a-et)CO2 correlated well with subsequent P(a-et)CO2 (R = 0.91, P less than 0.001). The mean difference of the subsequent P(a-et)CO2 values from the initial values was 0.05 +/- 0.80 mmHg (mean +/- SD) and was not significantly different from zero. In the patient population studied, P(a-et)CO2 thus remained generally constant during anesthesia.

Adult↗