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Biomedical subjects

W Wilhelm

Publications and source records attributed to W Wilhelm.

At least 73 records · Page 4Linked to original sources
PubMed1997

[Laparoscopic cholecystectomy--effect of position changes and CO2 pneumoperitoneum on hemodynamic, respiratory and endocrinologic parameters].

UNLABELLED: The effect of laparoscopic cholecystectomy on cardiopulmonary and endocrinological parameters results from various factors such as increased intraabdominal pressure (IAP), CO2, and the positioning. However, positioning has not yet been regarded. Reliable examination of the individual influencing factors requires standardized anesthesiological procedure and constant IAP. Presently, the effect of positioning is observed separately from those effects caused by the pneumoperitoneum with CO2 (PP) under standardized conditions. METHODS: 40 patients with no history of cardiopulmonary disease were analyzed. Preoperative medication, induction and management of general anesthesia, positioning of the patient and IAP (12 mmHg) were standardized. Hemodynamic, respiratory and endocrinological parameters were determined with the patient in a supine position and in the position typical for the procedure (15 degrees head-down and 10 degrees slant to the left), each with and without PP. Heart rate (ECG), endexpiratory pCO2 (peECO2), invasive blood pressure (radial art.), central venous pressure, partial arterial O2 saturation (psaO2), and ventilation pressures (peak, plateau) were monitored throughout anesthesia. The parameters pH, pCO2, BE, HCO3-, COHb, vasopressin, lactate, and ammonia were analysed in arterial and venous blood samples at predetermined set points: base line, 10 min after CO2 insufflation, 10 min after desufflation, and 1 h after extubation (cf. table 1). Statistical analysis was performed using the Wilcoxon-test with p < or = 0.05 considered statistically significant. RESULTS: Insufflation of CO2 lead to a 12% increase of heart rate in supine position and to even 18% in the position required for surgery. Same significant changes were observed for arterial blood pressure (21 or respectively 28%). Central venous pressure increased by more than 200% after CO2 insufflation. Endexpiratory pCO2 increased by 2.4 mmHg after CO2 insufflation in the supine position and by 5 mmHg in the surgical position. Ventilation pressures increased significantly by 16%. Analysis of the effect of PP on blood gases showed that pH decreased from 7.47 to 7.43, and arterial pCO2 increased by 5.1 mmHg to 38.7 mmHg and increased further after desufflation to values of up to 43.9 mmHg. Arterial pO2 decreased steadily (18% after insufflation). Vasopressin plasma levels increased exponentially from 3.03 to maximal values of 104.45 pg/ml. Ammonia and lactate showed the expected, nearly identical course. Lactate increased within the clinically and methodically irrelevative range, from 1.12 to 1.159 mmol/l. Ammonia decreased by 29%. CONCLUSIONS: The observed changes, i.e. heart rate, central venous pressure, and arterial blood pressure are caused and altered by CO2 insufflation and the various positioning of patients. The increased vasopressin concentration more than likely contributes to these changes. The query whether the position of the patient also causes a change in respiratory parameters and blood gas analysis cannot be differentiated except for the end-tidal pCO2. Inspite of the observed changes no cardiopulmonary complications occurred in this patient group. Therefore, it seems possible to omit invasive monitoring in cardiopulmonary healthy patients. In patients with concomitant history of cardiopulmonary disease, however, deteriorations due to laparoscopy should be thoroughly taken into consideration and studied further.

Acid-Base Equilibrium↗
PubMed1996

[Desflurane and isoflurane. A comparison of recovery and circulatory parameters in surgical interventions].

OBJECTIVES: The new volatile anaesthetic desflurane is characterized by very low blood-gas and tissue-blood partition coefficients, so that rapid induction of anaesthesia and shorter recovery times can be expected. The aim of this investigation was to compare the effects of desflurane and isoflurane on haemodynamics and recovery time when used as part of a balanced anaesthesia technique for elective surgery. METHODS: Fifty patients (18 years and older, ASA status I-III) scheduled for elective surgery (no laparoscopies) of at least 60 min duration were included in this open, randomised, phase-III clinical trial. After oral premedication with midazolam 7.5 mg 45 min before transfer to theatre, anaesthesia was induced with fentanyl 0.1 mg and thiopental 5 mg/kg; succinylcholine or vecuronium facilitated intubation. Desflurane and isoflurane, respectively, were used for maintenance of anaesthesia, both in 50% N2O, with the inspired concentration adapted to the degree of stimulation. All patients were ventilated in a semi-closed system; muscle relaxation was achieved with vecuronium. The electrocardiogram, heart rate (HR), and direct arterial blood pressure (BP) were recorded continuously and anaesthetic gas detection was performed by an infrared absorption technique. With termination of surgery the volatile anaesthetic was discontinued and the following emergence times recorded: spontaneous ventilation (VT > 300 ml), extubation, eye opening, correctly answering the date of birth, arrival in and possible discharge from the post-anaesthesia care unit (PACU). RESULTS: In all, 49 patients were studied at random (desflurane n = 24, isoflurane n = 25). Data of demographics and anaesthetic technique were comparable in both groups (Tables 2 and 3). Anaesthetic elimination (expressed as FA/FAO) was significantly more rapid in the desflurane group 3 min after termination of anaesthesia (Fig. 1). Comparing the emergence times, there was no significant difference between desflurane and isoflurane: in both groups patients opened their eyes 12 min (median time) after termination of the operation (Table 4). Haemodynamics (HR, systolic and diastolic BP) were comparable at intubation, skin incision, end of surgery, extubation, and in the PACU (Fig. 2a, b). In 2 patients a rapid increase in the inspired concentration of desflurane during induction of anaesthesia produced a profound sympathoadrenergic reaction with an excessive increase in BP and HR. Similar reactions in other patients did not occur when the inspired concentration of desflurance was slowly increased. CONCLUSIONS: Despite the physicochemical properties of the new agent, emergence times were similar for desflurane and isoflurane in our study. These results, which are in contrast to those of some other authors, are most probably due to the study design, which included the use of premedicants (midazolam) and a low dose of fentanyl. The reported sympatho-adrenergic reactions after rapid changes in the inspired concentration of desflurane during induction of anaesthesia have been observed by others as well. It seems that this initial cardiovascular stimulation can be avoided by slow increases in desflurane concentration. In summary, desflurane compares to isoflurane in balanced anaesthesia for general surgical procedures with regard to haemodynamics, while the time to awakening is not necessarely reduced.

Adolescent↗
PubMed1996

[Accuracy of measurement and overestimation of CO2 of two capnometers intended for potential use in emergency medicine].

UNLABELLED: Capnometry, the noninvasive measurement of end-expiratory CO2 concentration (cCO2, vol%) or calculation of its respective partial pressure (pCO2; mmHg) is an established method. However, for prehospital settings, capnometry is still used very restrictively, mainly owing to the respective devices used. The prerequisite for their use is sufficient accuracy (+/-2 mmHg) and easy handling. Two special capnometers (STAT CAP. Nellcor: mainstream, semiquantitative estimation; Capnocheck 8200, BCI: sidestream, quantitative measurement, numeric display), developed recently for potential use in emergency medicine, are said to fit these criteria. Therefore, the objective of the present investigation was to assess the accuracy and precision of both devices, comparing methods under standardized in vitro (reference gases) and in vivo (intubated and ventilated patients) conditions. METHODS: Both devices ("STAT CAP": pCO2 range, light bars; "Capnocheck 8200") were evaluated regarding the accuracy of pCO2 (Capnocheck) and the precision of the CO2 range (STAT CAP). Tests were performed with four dry gas mixtures (STPD) of defined composition and during ventilation of 20 intubated patients (BTPS). All measurements were compared with the alveolar gas monitor "AGM 1304" (Brüel & Kjaer, Denmark) as a reference method with a proven +/- 1 mmHg accuracy of pCO2 measurement. RESULTS: The "Capnocheck" (BCI) presented an accuracy of the pregiven pCO2 of 0.7-1.4 mmHg (dry gas mixtures, STPD) and an overestimation of 0.2 +/- 4.1 mmHg (BTPS) during ventilation with pure oxygen; inaccuracy during ventilation with 70% N2O in O2 proved to be + 1.2 +/- 1.7 mmHg (BTPS). Nellcor's "STAT CAP" failed to reach the target value in 10% of analyses, as shown by the respective segment bar of the display. CONCLUSION: Evaluation of the accuracy of capnometers must focus on the necessary pH2O correction and the possible effects exercised by O2 (and N2O) as well as the possible dependence on barometric pressure (if pCO2, mmHg, is the desired value). The "Capnocheck" showed an accuracy of more than 2 mmHg in dry gas mixtures as well as in humidified air. Concerning the practical use during constant artificial ventilation, the digital display and accuracy of the sidestream capnometer allow for reliable conclusions on patients' ventilation and circulation (CO2 elimination). The 90% accuracy of the segment bar display of Nellcor's "STAT CAP", per se covering only a rather broad range of 20 mmHg, obviously does not provide more than a rough overview. Therefore, the STAT CAP cannot be recommended for prehospital capnometry in the field. However, both the accuracy of the BCI capnometer (Capnocheck) and its numeric display and easy handling strongly recommend this device also for clinical use.

Blood Gas Analysis↗
PubMed1996

[The effect of midazolam after intranasal administration on spontaneous respiration and respiratory control in young children].

AIM: The aim of this study was to investigate the influence of intranasally administered midazolam in different doses on spontaneous respiration in children. METHODS: 40 children received in randomised order 0.2, 0.4 or 0.6 mg/kg b.w. midazolam intranasally or NaCl 0.9% as control. 10 minutes later, anaesthesia was induced by inhalation of halothane, nitrous oxide and oxygen. The children were breathing spontaneously at a PEEP of 5 cm H2O on a circle system with a fresh gas flow of 61/min (FIO2 = 0.33). Intubation was performed in deep anaesthesia without muscle relaxant. Halothane concentration was reduced to an endtidal concentration of 0.4 Vol%. With a baby pneumotachograph, minute ventilation, tidal volume, peak inspiratory and expiratory flow and respiratory rate were recorded during quiet breathing. Endtidal pCO2 was measured. Ventilation was then stimulated with 0.2 and 0.41/min CO2 and the same parameters were recorded. Regression analysis was performed for minute ventilation and endtidal pCO2 to obtain the slope which is a parameter for the sensitivity of the chemoreceptor mediated control of ventilation. RESULTS: The tidal volume and peak inspiratory flow were significantly reduced for a dose of 0.6 mg/kg compared to the control group. No statistical difference could be found for any other parameter between the control and study groups. CONCLUSION: We conclude that nasally administered midazolam reduces tidal volume and inspiratory peak flow in spontaneously breathing children at a dose of 0.6 mg/kg b.w. compared to control during halothane--nitrous oxide--oxygen anaesthesia. The CO2 mediated control of respiration under this condition is preserved.

Administration, Intranasal↗
PubMed1996

Comparison of two solutions with different glucose concentrations for infusion therapy during laparotomies in infants.

OBJECTIVE: Comparison of two commercially available solutions for intraoperative infusion therapy during laparotomies in infants using a standardized anesthetic technique (combination of general anesthesia with a caudal block). DESIGN: Prospective, randomized. SETTING: Infusion therapy during laparotomies in infants. PATIENTS AND METHODS: 12 infants aged 1-12 weeks (group I) and 12 infants aged 5-14 months (group II) received at random either solution A with 2.5% glucose and 70 mmol Na+ or solution B with 5.5% glucose and 100 mmol Na+ at a rate of 8 ml/kg/h. INTERVENTIONS: Central venous blood samples after induction of anesthesia and every 60 min for analysis of blood glucose, electrolyte, and hemoglobin concentrations. End of surgery: urine output during the operation and urine glucose and sodium concentrations. Statistical significance within the group: Friedmann Test, between the groups: U test by Wilcoxon, Mann and Witney. SIGNIFICANCE: p < 0.05. RESULTS (given as median and range): In group I blood glucose concentrations rose significantly during surgery, however, there was no significant difference between group A or B after 1 h. A: 234 mg/dl (156-351) vs B: 239 mg/dl (166-329)) or 2 h: A: 254 mg/dl (166-331) vs B: 272 mg/dl (176-468). In group II blood glucose levels rose significantly during surgery, however, children of group B showed significantly higher blood glucose levels than group A after 1 h [A: 119 mg/dl (114-227), B: 203 mg/dl (162-238)], 2 h [A: 154 mg/ml (106-185), B: 284 mg/dl (243-317)] or 3 h [A: 159 mg/dl (116-218), B: 248 mg/dl (201-363)]. The plasma and urine sodium concentrations did statistically not differ between the two solutions. CONCLUSIONS: Solutions containing 5.5% glucose infused with 8 ml/kg/h caused in both age groups of infants intolerable hyperglycemias. In young infants, also a solution containing 2.5% glucose infused at a rate of 8 ml/kg/h leads to hyperglycemia, while in older children this amount of glucose is tolerated. It is recommended that for abdominal surgery in young infants glucose and fluid substitution is separated, in order to infuse glucose at an even lower rate. Still, blood glucose levels have to be monitored closely.

Abdomen↗
PubMed1996

[Life threatening anaphylaxis after repeated cisplatin administration: case report and neu therapy concepts].

The present case reports of a 58-year-old female patient presenting with severe (III degrees) anaphylactic reaction due to repeated chemotherapy with Cisplatin. After resection of the advanced ovarian carcinoma the patient was presented with complaints of itching, angioneurotic edema and dyspnea in 1990 when Cisplatin had been infused for the first time. Due to relapse after four years a further operation was performed and as much of the tumour as possible was resected. Then again, Cisplatin was applied. Cortisone, H1- and H2-blockers were given prior to its application increasing the tolerance of treatment. Subsequent treatment with further Cisplatin infusion, however, resulted in severe anaphylactic shock with dyspnea and cold sweat. Emergency treatment included application of pure oxygen, two large i.v. cannulas, and 1.5 l of crystalloid, and 0.5 l of colloids (Gelafundin). Additionally, a potent vasoconstrictor (Akrinor) and 750 mg Methylprednisolone were given. Symptoms improved as blood pressure normalised, and the patient felt much better 20 minutes later. In summary, the present case report proves that anaphylactic shock induced by Cisplatin demands interdisciplinary action. This particularly applies to the interval between occurrence of the first shock signs and arrival of the emergency team.

Anaphylaxis↗
PubMed1995

[Three isoflurane preparations from various manufacturers. A comparison of isoflurane concentrations in fresh gas after vaporization with a Drager vaporizer type 19.3].

OBJECTIVES: The purpose of this study was to check the precision of the Dräger vaporizer model 19.3 when filled with three different preparations of isoflurane. METHODS: Six Dräger vaporizers model 19.3 calibrated with forene were filled with forene (Abbott), isoflurane (Lilly) and isoflurane (Pharmacia); gas output was measured by infrared absorption (Irina, Dräger) at vaporizer settings of 0.2, 0.4, 0.6, 0.8, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0 and 5.0 vol%, starting with a fresh gas flow of 2 1/min followed by 4, 6 and 12 1/min. Thus each of the three isoflurane preparations was checked in six different vaporizers and with four different fresh gas flows. RESULTS: Within the concentration range used in clinical practice there was no significant difference in the delivery of the three isoflurane preparations. Each of the six vaporizers produced a controllable and predictable concentration of the three preparations. CONCLUSION: Vaporizers of Dräger type 19.n calibrated with forene deliver the same predictable concentration of the volatile anaesthetic when filled with isoflurane from Lilly or isoflurane from Pharmacia instead of forene and may be used without impairment in patient safety. In addition, no specific calibration with one of the new isoflurane preparations is required.

Calibration↗
PubMed1994

[Spinal anesthesia in infancy using bupivacaine 0.5%. The effect of an adrenaline addition on duration and hemodynamics].

The duration of spinal anaesthesia in infants is short compared to adult patients. When tetracaine is used, the addition of epinephrine significantly prolongs the duration. For bupivacaine, however, the influence of epinephrine on the duration is not clear. We investigated the effects of epinephrine 1:200,000 added to bupivacaine 0.5% on duration and haemodynamics. PATIENTS AND METHODS. Ten former pre-term infants with postnatal respiratory problems, scheduled for bilateral inguinal hernia repair, were enrolled in the study after informed parental consent had been obtained. The infants were fasted at least 4 h prior to surgery. If they did not receive i.v. infusions before surgery, a bolus of 10 ml/kg Ringer's acetate was injected after inserting the i.v. cannula, followed by a continuous infusion of 8 ml/kg 2/3 N NaCl with 5% dextrose. Spinal anaesthesia was performed in a sitting position with 0.6 ml bupivacaine 0.5%. Five patients received plain bupivacaine (group I) and five bupivacaine with epinephrine 1:200,000 (group II). Heart rate registered by ECG and non-invasive blood pressure were recorded prior to positioning the baby for lumbar puncture and 2, 5, 10, and 20 min after injection of bupivacaine. The duration of spinal anaesthesia was defined as the time from injection to the time when the first movements of the legs were observed after stimulation. For testing statistical differences the U test was used between the groups and the Wilcoxon and Wilcox test within the groups. RESULTS. (expressed as median and range). Additional epinephrine significantly prolonged the duration of spinal anaesthesia (group II: 95 min [60-120] vs group I: 50 min [37-85]). Haemodynamic parameters did not differ at any time between or within the groups. In group I, one infant had high spinal anaesthesia with impaired respiration but without cardiovascular effects; after 10 min of assisted ventilation by mask, sufficient respiration as judged by pulse oximetry and clinical observation had returned. The duration of spinal anaesthesia in this child was 60 min. CONCLUSIONS. Epinephrine 1:200,000 significantly prolongs the duration of spinal anaesthesia in former preterm infants. Haemodynamic parameters in this age group remain unchanged during spinal anaesthesia and are not influenced by the addition of epinephrine.

Anesthesia, Spinal↗