Biomedical subjects
W Dick
Publications and source records attributed to W Dick.
[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.
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.
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.
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.
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.
Recommended guidelines for uniform reporting of data from out-of-hospital cardiac arrest: the Utstein Style. Task Force of the American Heart Association, the European Resuscitation Council, the Heart and Stroke Foundation of Canada, and the Australian Resuscitation Council.
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[Transfusion of blood and blood products].
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[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.
[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)
Undergraduate education in emergency medicine.
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Cefpodoxime: comparable evaluation with other orally available cephalosporins. With a note on the role of beta-lactamases.
The antibacterial activity of cefpodoxime, a new orally active methoxy-imino cephalosporin was evaluated in 470 recent isolates of gram-positive cocci and gram-negative rods from clinical specimens and compared to that of other orally active beta-lactam compounds. Cefpodoxime was highly active against ampicillin-resistant enterobacteria producing the plasmid-mediated TEM-1, TEM-2 or OXA-1 enzymes, as was the case for the other newer compounds. However, it was poorly active against cefuroxime-resistant (MIC greater than or equal to 16 mg/l) E. coli isolates, thus resembling cefetamet and cefixime. It was inactive against isolates exhibiting a production of large amounts of class I beta-lactamase, as was the case with all other compounds studied. Cefpodoxime was highly active against beta-hemolytic streptococci and against Haemophilus influenzae, resembling the related agents. Moreover, its activity against Staphylococcus aureus was comparable to that of cefotaxime and exceeded that of cefetamet and cefixime. Cefpodoxime and the other methoxyimino cephalosporins exhibited a poor affinity to the plasmid-mediated TEM-2 and OXA-1 enzymes. The hydrolysis of cefpodoxime by class I beta-lactamases was barely detectable, whereas it served as a moderate substrate for the enzyme from Klebsiella oxytoca 3951. Cefpodoxime, cefetamet and cefixime were slowly inactivated by the enzyme from Proteus vulgaris 4917 (an enzyme with cefuroximase activity) and much poorer substrates than cefotaxime.
Heterogeneity of beta-lactamase production in Pseudomonas maltophilia, a nosocomial pathogen.
Twenty Pseudomonas maltophilia isolates were examined for susceptibility to beta-lactam antibiotics, including carbapenems, and for beta-lactamase production. All the isolates were resistant to imipenem (MICs 64-512 mg/l) and to a lesser extent, to meropenem (MICs 16-256 mg/l). None of the isolates produced significant amounts of beta-lactamase without induction. Among the beta-lactams studied imipenem proved to be the most potent inducer; meropenem was a weaker inducer. Interestingly, 6-amino-penicillanic acid, even in concentrations up to 100 mg/l, entirely lacked induction activity. In any case enzyme production was drug concentration dependent and transient. Isoelectric focusing revealed 6 different enzymes distinguished by their different isoelectric points (pH 6.2, 8.3, 8.5, 9.0, 9.2 and 9.4). This suggested the lack of a unique beta-lactamase profile in P. maltophilia. Addition of 5 mM cyclic AMP (cAMP) or 0.5 mM cAMP-N6, O2-dioctanoyl (a lipophilic derivative) resulted in a marked drop of beta-lactamase induction by imipenem as compared to the control assay. Monitoring of carbapenem hydrolysis by cell-free supernatants revealed inactivation of both carbapenems. Meropenem was inactivated about 5 times more rapidly than imipenem. Our studies revealed that beta-lactamase production in P. maltophilia as well as growth kinetics were influenced to a considerable extent by the nutrient medium employed.
Influence of temperature on beta-lactamase production and outer membrane proteins in gram-negative rods.
The influence of temperature (ranging from 28 to 42 degrees C) was studied on the phenotypic expression of chromosomally mediated beta-lactamases in gram-negative clinical isolates and in their beta-lactamase-depressed resistant counterparts. The enzymes were expressed most intensely at lower temperatures (28 or 32 degrees C). In most strains the enzyme was barely detectable at growth temperatures of 42 degrees C independent of the inducer employed. The release of the enzyme into the surrounding medium was marginal even at a growth temperature of 42 degrees C. The major outer membrane proteins revealed discrepancies dependent on the growth temperature only for the Providencia rettgeri W 862 strain. Thus, it can be concluded that the phenotypic expression of chromosomal beta-lactamase is temperature dependent to the effect that the enzymes are most expressed at 28 or 32 degrees C. This agrees well with the increased susceptibility to most beta-lactams due to the lowered beta-lactamase production at higher temperatures. This effect was pronounced most strikingly in Proteus vulgaris.
[Analysis of risk in the perioperative period].
Operative risks should be assessed before surgical intervention not only by heuristic means, but in addition also by quantitative methods. ASA-classification and Recovery Index (McPeek) are offered for a critical routine assessment of global perioperative risk.
[Anaphylactoid reaction to a non-ionic roentgen contrast medium in general anesthesia].
The occurrence of adverse reactions is decreasing since the introduction of non-ionic contrast media. Anaphylactoid reactions during general anaesthesia are rare and hitherto only documented with the administration of ionic compounds. We report an episode of hypotension, tachycardia, bronchospasm and urticaria following application of a non-ionic contrast medium (Iopamidol) during isoflurane anaesthesia. We conclude that a combinent use of anaesthesia and non-ionic contrast media does not guaranty protection from anaphylactoid reactions to iodinated radiopaque compounds.
[Characteristics of cardiopulmonary resuscitation in pregnant women].
Cardiopulmonary resuscitation (CPR) during pregnancy is a rare event, but due to the increasing number of pregnant women with significant medical disorders it will gain more importance in the near future. Effective CPR with respect to survival of mother and infant can only be accomplished under optimal conditions. We discuss important pathophysiological alterations during pregnancy and, including recommendations in the available literature, we present a standardized protocol for life support for mother and infant. The protocol depends on the progress of the pregnancy. Compared to non-pregnant patients, pregnant women must be placed in a left lateral position immediately. If possible, the decision to perform open-chest CPR has to be made within 15 min of unsuccessful closed-chest CPR. In addition, during late pregnancy there should be no delay in performing an emergency cesarean section, even during CPR.