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Biomedical subjects

W Dick

Publications and source records attributed to W Dick.

At least 19 recordsLinked to original sources
PubMed1992

[Histamine release during induction of combination anesthesia using nalbuphine or fentanyl. Modulation of the reaction by premedication with promethazine/pethidine].

In a controlled clinical trial in patients admitted for general surgery (mainly abdominal and thyroid), histamine release following nalbuphine 1 mg/kg i.v. versus fentanyl 5 micrograms/kg i.v. was studied in the course of an otherwise routine induction with promethazine/pethidine as premedication 30 min before the opioids and alcuronium-flunitrazepam-thiopental 5 min later. Succinylcholine was given before intubation and further analgesia was obtained by repeated administration of either nalbuphine or fentanyl. Plasma histamine levels were measured by a specific fluorometric assay, heart rate and blood pressure were measured for assessing hemodynamics, and clinical signs of anaphylactoid reactions such as skin eruptions and arrhythmias were registered. RESULTS. Nalbuphine and fentanyl both released histamine with an incidence of more than 40%. In addition, nalbuphine potentiated the histamine release evoked by the sequential administration of alcuronium-flunitrazepam-thiopental in one complex of application. The incidence of histamine release in the nalbuphine group was 6/13 = 46%, in the fentanyl group only 1/11 = 9% (chi2 test, P less than 0.05). Furthermore, this study showed high histamine levels after succinylcholine and intubation in a relation to time of administration that suggested histamine release as a stress response to intubation. Finally, the incidence of histamine release after a second injection of the opioids was still 30%. A direct correlation between plasma histamine levels, hemodynamic changes, and skin reactions could not be shown. A detailed causality analysis with histamine release as a contributory determinant showed histamine release less detrimental to hemodynamic stability than the opposite, which had been expected. However, the promethazine administered 30 min before induction of anaesthesia had strong H1- and H2-receptor antagonistic activity and was given with optimum timing for H1- and H2-prophylaxis. CONCLUSION. The study demonstrated that histamine release during anaesthesia and surgery depends strongly on the time sequence of drugs and measures used. Histamine release is not predictable from studies in human volunteers alone; studies in patients have to be added. Histamine release is not always detrimental. H3-receptor-mediated effects after H1- and H2-prophylaxis may help patients to counteract the effects of a series of vasoactive drugs given during induction of anaesthesia.

Adult↗
PubMed1992

[Propofol for sedation during postoperative mechanical ventilation. A comparative study with Lytic Mixture].

Propofol infusion was found to provide excellent sedation and rapid recovery in intensive care. The present study compared Propofol with lytic solution (lytic solution = mixture of 100 mg Pethidine, 50 mg Promethazine and 0.6 mg Dihydroergotamine) during 6 hours of postoperative artificial ventilation. 60 patients after major abdominal surgical procedures were studied with ethical committee approval and informed consent. Patients were randomly allocated to receive either Propofol or lytic solution. We aimed at a sedation level of stage 5 according to the Ramsey score. The mean drug dosages were 3.9 mg/kg/h of Propofol and 4.2 ml/h of lytic solution. Hemodynamic values, blood gases as well as various biochemical measures did not show any difference between the groups. At the end of the sedation period triglyceride concentrations were significantly higher in patients receiving Propofol (166 + 79 mg/dl) compared to the control group (97 + 60 mg/dl). Significant and relevant differences were found for the times of recovery after discontinuation of the sedative. These times were very short in the Propofol group. Furthermore, in view of a longer recovery time after lytic solution in this group the respiratory rate was significantly slower up to the end of the observation period. We conclude that a major advantage of Propofol in the present study was the rapid recovery after 6 hour sedation. Patients gain vigilance rapidly and sufficient spontaneous respiration within minutes. Not at least thanks to these facts patient's safety can be improved in the recovery period.

Abdomen↗
PubMed1992

[Dorsal stabilization of thoracic and lumbar vertebral injuries].

The concept of angle-stable transpedicular screw-rod instrumentation, realized in the different models of internal spine fixators with intrinsic stability, allows secure stabilization of the most unstable fracture patterns, limited-segment fixation and three-dimensional reduction of the fragments. The canal diameter is improved by ligamentotaxis and, if necessary, by hemilaminectomy and fragment impaction. Late collapse of the upper disk space must be anticipated and may lead to some increase in kyphotic deformity. The situations are identified where an additional formal interbody fusion is recommended.

Fracture Fixation, Internal↗
PubMed1992

[Which factors determine the critical hematocrit as an indication for transfusion?].

The question as to what extent the hematocrit (Hct) is a strong indicator for or against the need for transfusion of whole blood or blood products is still controversial. In order to enable the clinician to make a definite decision, a number of aspects have to be taken into consideration. The human organism has only limited oxygen reserves, and these are even more limited under pathological conditions. Oxygen flux - the amount of oxygen transported by the blood in 1 min - is a critical factor in the oxygenation of the human body. Another critical factor is oxygen consumption, which is highly variable depending on the presence of conditions such as rest, shivering, seizures, hypothermia, etc. Furthermore, different organ systems have different oxygen consumption rates. The ratio of oxygen consumption to oxygen flux is referred to as the oxygen extraction rate or oxygen utilization. Under normal conditions oxygen uptake is independent of oxygen flux, and thus independent of blood flow. Under conditions of organ dysfunction, however, oxygen deficiency may be present without being recognized on standard clinical diagnostic parameters. The normal human organism has a number of possibilities to compensate for acute or chronic anemia, i.e., increases in cardiac output, organ perfusion, 2,3-DPG content, a shift in the oxygen dissociation curve, etc. These compensatory mechanisms may, however, be restricted or cease to function under conditions of acute or chronic disease. Arterial and mixed-venous PO2 and oxygen content are some of the parameters used to assess the oxygen reserves available to the organism even under critical conditions. Although oxygen content is the most significant of these parameters, accurate measurement of this parameter remains a problem of laboratory medicine. PVO2 is of only limited importance under conditions of anemia. Minimum oxygen content or minimum oxygen flux values should under no conditions be approximated during anesthesia or intensive care. The critical Hct as an indicator for or against transfusion of blood or blood products is considerably modified by restricted organ function, anesthesia, intensive care treatment, resuscitation, etc.(ABSTRACT TRUNCATED AT 400 WORDS)

Anesthesia↗
PubMed1992

[Atropine in the premedication of patients at risk. Its effect on hemodynamics and salivation during intubation anesthesia using succinylcholine].

Should atropine be administered for premedication? This question continues to be controversial; in particular, the combined administration of atropine and succinylcholine has been investigated with conflicting results by numerous researchers. The present study was carried out to assess the effect of premedication with atropine on hemodynamic variables and salivation in patients assigned to ASA class II and III. METHODS. Eighty ASA class II or III patients received pethidine 1.0 mg/kg and promethazine 0.5 mg/kg i.m. 30 min prior to induction of anesthesia and atropine, either 0.01 mg/kg i.v. 10 min or 0.01 mg/kg i.m. 30 min prior to a standardized anesthetic induction with alcuronium (precurarizing dose), thiopental, and succinylcholine. In the control groups (20 patients each), no atropine was given. Systolic, diastolic, and mean arterial pressures (MAP) were measured. The ECG was monitored for arrhythmias. Salivation was assessed semiquantitatively using swabs positioned within the pharyngeal space. RESULTS. Ten minutes after the administration of atropine i.v., a significant increase in heart rate (HR) was observed; this did not occur within 30 min after administration of atropine i.m. At the time of tracheal intubation, HR was significantly increased in both i.v. atropine risk groups. After atropine i.m., an increase in heart rate during intubation was observed in ASA class II patients only. No increase in heart rate occurred in the control groups during tracheal intubation. Neither i.m. nor i.v. atropine had any significant effect on blood pressure. Arrhythmias occurred in a few cases with both routes of administration; several instances of marked tachycardia were recorded.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

[Post spinal headache. Its incidence following the median and paramedian techniques].

A lack of uniform methodology used by different authors in the assessment of different puncture techniques in spinal anesthesia formed the basis of the current study, which compared under randomized conditions the incidence of post spinal headache after a median or paramedian (lateral) approach. MATERIALS AND METHODS. Two hundred and fifty ASA physical status II and III patients, aged 50-85 years, scheduled for transurethral prostate surgery under spinal anesthesia were investigated. The patients were comparable with regard to weight and height (Table 1). No premedication was given and, 30 min prior to surgery, all patients received normal saline 400-500 ml i.v. The patients were randomly divided into two groups of 125 patients each to receive 4 ml 0.5% bupivacaine in 5% glucose (specific gravity 1.017 at 20 degrees C) using the median or paramedian (lateral) approach according to the following scheme (Table 2): I: 4 ml 0.5% bupivacaine/median approach; II: 4 ml 0.5% bupivacaine/paramedian approach. The study was carried out in a double-blind fashion. Neither the patient nor the investigator evaluating the post spinal headache was aware of which technique had been used. Lumbar puncture was performed by a midline approach at the L3-4 interspace using a 25-gauge (Whitacre) spinal needle with the patient in the sitting position group I. The bevel of the spinal needle was directly laterally, so that the dural fibers that run longitudinally were spread rather than transected. When using the paramedian approach (group II), patients were placed in the flexed lateral decubitus position and the spinal needle inserted 1 cm medial and 1 cm lateral and caudad to the lowest part of the posterior superior iliac spine and then directed medially and cephalad at an angle of 55 degrees into the subarachnoid space. Postoperatively, patients were allowed to move as soon as possible; no prophylactic bed rest was ordered. Starting from the 1st postoperative day, patients were evaluated by an independent observer and asked whether they were suffering from any problems concerning anesthesia. Typical post-puncture headache was defined as invariably bifrontal and occipital, frequently involving the neck and upper shoulders, and being aggravated by the upright position. Statistical analysis of the data was performed using the Mann-Whitney rank-sum test for unpaired samples. A P value of less than 0.05 was considered statistically significant. RESULTS. Twenty-six of 250 patients (10.4%) developed post spinal headaches. Comparing both groups, 11/125 (8.8%) patients in the median group (group I) versus 15/125 (12%) in the paramedian group (group II) had typical post-puncture headaches. Within the group of patients aged 50-60 years, the paramedian approach (group II) showed a significantly higher headache rate compared with group I (P less than 0.05). Neurologic sequelae were not observed; 6 patients received epidural injections of autologous blood while the rest of the patients suffering from post spinal headache were treated conservatively with bed rest, analgesics, and fluids. CONCLUSIONS. The results indicate that the incidence of post spinal headache is higher in younger patients when using the paramedian (lateral) approach. However, our findings suggest that the choice of lumbar puncture technique--median or paramedian--is of little importance in regard to post-puncture headache in elderly patients. The paramedian approach is especially useful when degenerative changes are encountered in the interspinous structures in elderly patients, when an ideal position is difficult to achieve.

Aged↗
PubMed1992

[The emergency telephone number--the essential weak link in an emergency system. Prospective studies involving cardiac arrests observed by bystanders].

The first link in the "chain of survival" concept is the activation of the emergency medical system (EMS) by a bystander after recognition of cardiac arrest (CA) or its immediate prodrome. Our ongoing study is aimed at evaluating the current effectiveness of bystander EMS activation for all cases of CA in the city and area of Mainz. Methods. Starting February 1991, we began to prospectively examine collapse-intervention intervals in all cases of CA treated by our physician-manned ambulance. Precision voice recorders carried by the ambulance crews are activated and linked to the EMS dispatcher to time the arrival of the ambulance vehicle. Time intervals starting from the time of collapse are then reconstructed from the dispatcher's time and the tapes. The emergency phone number dialled initially by the bystander and the time of collapse in witnessed cardiac arrests are identified. RESULTS. Sixty-six CAs were witnessed and included in this study. In 20% of those cases, the number dialled initially by the bystander was 19222 (EMS dispatcher), in 38% 110 (police), and in 42% other numbers (family practitioners or their on-call service, fire department). The time interval, as median (25th percentile; 75th percentile), between collapse and receipt call by the emergency dispatchers was 4 min (2; 8) for all patients (n = 66), and 6.5 min (3; 12) whenever numbers other than emergency phone numbers were dialled. All following time intervals (start of BLS or ACLS procedures) showed differences (P less than 0.05) between the 110 or 19222 group [BLS: 8.5 min (4.8; 13.1) or 10 min (7.35; 12.1); ACLS: 11.3 min (9.1; 13.45) or 12.9 min (10.6; 21.5)] vs the group, in which other phone numbers were initially dialled [BLS: 15.25 min (9.25; 19.4); ACLS: 20.11 min (12.6; 28.3)]. The first ECG rhythm showed VF in 56% and 54% in case 110 and 19222 were dialled, but only in 32% in the other group. CONCLUSION. Even one single weak link in the "chain of survival" can lower overall survival rates. An indispensable, but apparently underrated component of an effective EMS includes an informed citizenry able to call swiftly for help. Lack of an unequivocal emergency number, well known and accepted by the citizens, produces confusion and delays. In our systems, the correct medical emergency phone number (19222) was dialled in 20% of the cases only, thus demonstrating clearly the lack of public awareness of this 5-digit number. In a higher percentage, the three-digit police number (110) was dialled. In cases where numbers other than emergency numbers were dialled (42%), the longest time intervals between collapse and receipt of call by the dispatchers occurred, associated with the longest time intervals until initiation of CPR and the lowest percentage of patients found in ventricular fibrillation. We conclude that establishment of a simple three-digit EMS phone number, preferentially Europe-wide, in combination with an intensification of public awareness, could be a vital step not only to reduce time intervals between collapse and CPR in our EMS system but also to improve survival.

Emergency Medical Service Communication Systems↗
PubMed1992

General anaesthesia versus epidural anaesthesia for primary caesarean section--a comparative study.

Forty-seven healthy parturients undergoing elective Caesarean section were randomly allocated to either general anaesthesia (n = 24) or epidural anaesthesia (n = 23) under standardized anaesthetic and surgical conditions. Seven women of the epidural group required additional systemic analgesia or sedation following delivery of the neonate. Nine of 24 newborns obtained 1-min Apgar scores below 7 after general anaesthesia compared to only 3/23 after epidural anaesthesia. The time period to establish normal colour in the babies was 2.2 min after epidural and 4.9 min after general anaesthesia. Three of the 24 general-anaesthesia newborns demonstrated a tendency to hypotonia compared to only one in the epidural group. Twenty-four hours and 7 days after delivery all infants of both groups were completely normal. At the time of delivery maternal PO2 was higher in the general anaesthesia compared to the epidural group, due to higher inspired oxygen concentrations. Comparable results were obtained in umbilical PO2 venous values; lower pH values, however, were observed in the umbilical artery after general anaesthesia. There were no significant differences in the glucose levels between the groups. A significant correlation was established between uterine incision-delivery interval and 1-min neonatal Apgar scores in the general-anaesthesia group, but not in the epidural group. Our investigation did not show either the incision-delivery interval or the start of operation-delivery interval to play a role in neonatal outcome. Epidural anaesthesia is superior to general anaesthesia in Caesarean section under normal conditions with regard to neonatal outcome. Whether this is also true for critical conditions cannot be concluded from this study.

Adolescent↗
PubMed1991

Controlled clinical trials and cross-sectional studies with plasma histamine measurements and histamine receptor antagonists: solving the problem of preoperative H1- + H2-prophylaxis by asking new questions?

The problem of a preoperative histamine H1- + H2 - prophylaxis was tackled by a group of new studies including randomized controlled clinical trials and cross-sectional studies with plasma histamine measurements and administration of H1- + H2 - antagonists to a control group. The first study demonstrated serial histamine release in the induction of anaesthesia up to 4 times in a single patient. Basal plasma histamine levels in resting subjects fell below 100 pg/ml during the time necessary for preparation of the surgical patient. Hence, spikes of elevated plasma histamine concentrations corresponded to histamine release. Although this histamine release very often was less than 1 ng/ml plasma histamine, it created systemic reactions after atracurium. The cut-off point of 1 ng/ml for such anaphylactoid reactions does no longer exist, also lower plasma levels are of patho-physiological significance. The clinical signs of histamine release in the induction of anaesthesia vary from drug to drug. Sometimes tachycardia and hypertension produce the highest likelihood ratio, sometimes tachy- and bradycardia, but no changes in blood pressure as in the case of atracurium. It is concluded that the reasons why histamine release in anaesthesia and surgery is so much underreported and under-estimated include the present paradigms about plasma histamine levels and the "classical picture" of histamine release. Both are no longer valid and need a re-assessment.

Adolescent↗
PubMed1991

The fixateur interne in the reduction and stabilization of thoracolumbar spine fractures in patients with neurologic deficit.

A prospective analysis of 80 consecutive patients who underwent stabilization with the fixateur interne for thoracolumbar spine fractures with complete or incomplete paraplegia was undertaken to determine the results after bone healing. Follow-up examination at an average of 35 months (minimum, 24 months) included all 76 patients still alive. One patient died from a pulmonary embolism, and there were three other unrelated deaths. The mean wedge angle of the fractured vertebra was corrected from 17.4 degrees to 7.9 degrees and remained almost unchanged after 1 year (8.4 degrees) and 2 years, or 1 year after implant removal (8.2 degrees). Also, the wedge index showed nearly no bony loss of correction within the reduced fracture vertebra (0.61 before operation, 0.83 after operation; 0.81 at 1-year follow-up, 0.81 at 2-year follow-up, respectively). In the kyphosis angle measured by the Cobb method, however, there was a loss of 5 degrees after implant removal within the next year because of the disc space collapsed above the fractured vertebra. In this series, 70% of the cases had no formal fusion. All 29 cases of translational displacement of 4-36 mm were anatomically reduced. No neurologic or vascular complication occurred. Posterolateral fusion or transpedicular interbody fusion in the disrupted disc space is recommended.

Adult↗
PubMed1991

Carbapenem resistance in Enterobacter aerogenes is due to lipopolysaccharide alterations.

The extensive characterization of 2 clinical Enterobacter aerogenes isolates resistant to all beta-lactam antibiotics including imipenem revealed that imipenem resistance could not be attributed to overproduction of the chromosomal beta-lactamase; moreover, it was lost after subcultivation and can be thus considered as unstable. The comparison of sensitive and resistant clones revealed that the beta-lactamase in the resistant clones was less inducible in the resistant clones and moreover, there was an altered 2-keto-3-deoxyoctonate/carbohydrate ratio in the resistant clones as compared to the imipenem-sensitive clones, thus suggesting alterations in the lipopolysaccharide (LPS). Neither enzymatic degradation of both imipenem and meropenem nor alterations of the outer membrane proteins could be observed. These findings make it apparent that this type of resistance is likely due to an impaired uptake of the agents due to LPS alterations.

Bacterial Outer Membrane Proteins↗
PubMed1991

[Postoperative analgesia following spondylodesis using a peridural catheter placed during surgery. Results of a pilot study].

For the treatment of postoperative (p.o.) pain following vertebral surgery, systemic analgesics are frequently used in high doses with a variety of side effects. It was the aim of this study to investigate p.o. epidural catheter analgesia in 20 patients following surgical correction of scoliosis using the Cotrel and Dubousset technique. METHODS. The patients received balanced general anesthesia with fentanyl and isoflurane. At the end of the operation, before closing the fascia, an epidural catheter was placed by the orthopedic surgeon. After extubation and following evaluation of the motor function of all extremities. 6-10 ml bupivacaine 0.25% was injected into the epidural catheter followed by continuous administration of 0.25% bupivacaine 4-8 ml/h. Analgesic level and hemodynamic parameters were monitored. Pain was measured by the visual analogue scale. If analgesia was not sufficient, the patients received tramadol or piritramide intravenously. RESULTS. In 11 of 20 patients epidural analgesia was rated adequate; 5 needed additional systemic analgesics, and in 4 effective analgesia was not achieved with either epidural analgesia or systemic opioids. No complications were observed. DISCUSSION. The pilot study documented that epidural analgesia using an intraoperatively placed epidural catheter can be used for p.o. pain relief after vertebral surgery using the Cotrel and Dubousset technique. Additional studies will compare the method described to other pain-relieving procedures.

Adolescent↗
PubMed1991

[The use of the laryngeal mask--a practical method?].

In 1985 Brain et al. published their first experience with the laryngeal mask, developed by themselves. With this mask it is possible to seal the larynx and ventilate a patient during anesthesia without endotracheal intubation. Meanwhile, further reports of successful use have been published, especially in Great Britain. We decided to investigate this new anesthetic device. In 15 patients (ASA groups I and II) undergoing elective operations in the supine position the laryngeal mask was inserted after induction of anesthesia with propofol and alfentanil (Fig. 1). Positioning of the laryngeal mask was carried out as described by Brain. In all patients the laryngeal masks could be inserted without any problems, manual ventilation of the patient was performed immediately, and ventilating pressures never exceeded 15 cm H2O. We observed neither complications related to airway control nor technical problems. Cardiovascular parameters and arterial oxygen saturations were always in the normal range (Fig. 2). In 3 patients quick movements of the head were carried out during repositioning of a fractured zygomatic arch, but no complications due to a possible changed position of the laryngeal mask occurred. Postoperatively two patients reported airway complaints such as sore throat. Our investigation confirmed the previously described advantages of the laryngeal mask. We consider its use to be especially indicated in general anesthesia for short surgical or diagnostic procedures or if specific complications of endotracheal intubation should be avoided. A critical aspect in the use of the laryngeal mask is the fact that there is no complete isolation of the trachea and, therefore, an insufflation of the stomach or aspiration could occur, especially during critical situations (e.g. bronchospasms).(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesiology↗