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Biomedical subjects

M Doehn

Publications and source records attributed to M Doehn.

At least 55 records · Page 3Linked to original sources
PubMed1990

Diabetic autonomic neuropathy: abnormal cardiovascular reactions under general anesthesia.

The influence of diabetic autonomic neuropathy upon the behavior of the circulatory system was investigated in 56 patients who had undergone ophthalmological surgery. A standardized test combination (variability in heart rate during deep breathing. Valsalva ratio, 30:15 ratio, change in blood pressure from lying to standing, sustained handgrip test) was used to study the patients' cardiovascular reflectory reactions. The patients were then divided into the following groups: Group I, non-diabetics. Group II, diabetics without autonomic neuropathy. Group III, diabetics with autonomic neuropathy. The anesthetic (induction by barbiturates and conduction by inhalation agents) and the surgical procedure (pars plana vitrectomy) were standardized and always identical. During anesthesia patients in group III experienced hypotensive reactions (systolic blood pressure below 90 mm Hg) significantly more often (72.2%) than patients in group I (25%). In order to achieve stability in blood pressure the patients of group III had to be given vasoactive drugs much more often (77.8%) than the patients of group I (12.5%) and those of group II (35.7%). We found a significant correlation between the degree of autonomic dysfunction and the largest drop in blood pressure under narcosis (r = -0.60, P less than 0.001). However, marked variability in heart rate and cardiac rhythm disorders during anesthesia were seen only in patients of groups I and II. These results prove the atypical hemodynamic behavior and especially the extreme instability in blood pressure in diabetic autonomic neuropathy under general anesthesia. Therefore we consider it to be very helpful to check the cardiovascular reflectory status of diabetics preoperatively.

Adult↗
PubMed1990

Restoring sinus rhythm after intraoperatively occurring isorhythmic AV dissociation by the use of K-Mg aspartate or Mg aspartate.

In a prospective randomized clinical trial we tested the efficiency of different electrolyte infusions for the treatment of intraoperatively occurring isorhythmic AV dissociation (ID). Only infusions containing Mg were effective in restoring sinus rhythm: the infusion of K-Mg aspartate led to a conversion of intraoperatively occurring ID into sinus rhythm in 72% (p less than 0.01) of the patients and the infusion with Mg aspartate alone did so in 67% (p less than 0.01) of the patients. The rate of spontaneous conversion was 22% in the control group treated with Ringer's solution. The use of infusions containing K aspartate was ineffective in restoring sinus rhythm.

Adolescent↗
PubMed1990

[Unstable blood pressure during anesthesia in diabetic patients with autonomic neuropathy].

Diabetic autonomic neuropathy (AN) as a risk factor of surgical procedures has so far been described in case reports, but no controlled clinical studies are known. Therefore, we intended to study systematically the perioperative relevance of the autonomic dysfunction. 32 ophthalmosurgical patients (20 diabetics, 12 non-diabetics) were investigated. Cardiovascular autonomic function was examined preoperatively by a combination of tests (heart rate variations during deep breathing, Valsalva ratio, 30:15 ratio, postural hypotension, sustained hand grip). A scoring system based on these tests provided the staging of the autonomic involvement of the patients (AN score). The anaesthesiological management (thiopentone, N2O, halothane) and the operative procedure (vitrectomy) were uniform. A significant correlation was found between the AN score and the coefficient of variation of the systolic (r = 0.70, p less than 0.001) resp. the diastolic (r = 0.52, p less than 0.01) blood pressure during anaesthesia. No correlation was found between the intraoperative variability of the arterial blood pressure (coefficient of variation) and the age of the patients resp. the preoperative value of the blood pressure. In diabetics with severe autonomic neuropathy (AN score greater than 5) hypotensive reactions were seen very often during the operation. The results demonstrate that the haemodynamic stability in the perioperative period depends on the severity of the autonomic dysfunction. Diabetics with severe autonomic neuropathy have a high risk of blood pressure instability. Non-invasive diagnostic methods allow to identify these patients preoperatively.

Adult↗
PubMed1989

[Air embolism in the sitting position. Oxygen/nitrogen versus oxygen/laughing gas].

UNLABELLED: Venous air embolism (VAE) is a well-known complication of neurosurgical procedures performed in the sitting position. Nitrous oxide (N2O) intensifies the hemodynamic alterations conditioned by VAE. Therefore the administration of N2O must be discontinued immediately if VAE occurs. Nevertheless, it is still not clear whether N2O should be avoided in such operations as a general policy. The aim of the present study was to investigate the incidence and severity of VAE with O2/N2 as opposed to O2/N2O anesthesia. METHODS. In all, 42 patients (19 men, 23 women) aged 23-80 years were investigated in a randomized order. In all cases an intracranial operation was carried out with the patient in the sitting position. The anesthesiologic management was uniform: modified neuroleptanalgesia (fentanyl, flunitrazepam, droperidol), relaxation with pancuronium, endotracheal intubation, moderate hyperventilation (PaCO2 30-35 mmHg) without PEEP. Half (21) of the patients (group 1) were ventilated with O2/N2 (1:1) and the remaining patients (group 2) with O2/N2O (1:1). Heart rate (HR) arterial blood pressure (AP), central venous pressure (CVP), end-tidal CO2 tension (PE'CO2), and body temperature were monitored continuously. Arterial blood gases were checked once per hour at least. VAE was signaled by changes in the ultrasonic Doppler sounds or a rapid decrease in the end-tidal CO2 tension. The diagnosis of VAE was confirmed by aspirating air bubbles through the right atrial catheter. A vacuum-driven device was used to suction off the embolized air and measure the aspirated air volume. Pulmonary gas exchange was defined by the arterial to end-tidal CO2 difference (PaCO2 - PE'CO2) and by the alveolar arterial O2 quotient (PAO2 - PaO2/PAO2). If a VAE was recognized N2O administration was stopped immediately and ventilation was continued with pure oxygen. Postoperatively all patients were ventilated. RESULTS: The incidence of VAE was similar in both groups: VAE occurred in five patients in group 1 and in six patients in group 2. In isolated cases distinct increases in the CO2 difference (PaCO2 - PE'CO2) or the O2 quotient (PAO2 - PaO2/PAO2) resulted, with no significant difference between the groups. In patients with VAE the aspirated gas volume (median 6.0 ml in group 1, 75.5 ml in group 2; P less than 0.01) and the duration of aspiration (median 5.0 min in group 1, 22.5 min in group 2; P less than 0.05) were significantly different in the two groups. HR was significantly lower in group 2 1 and 4 h after the beginning and at the end of the operation. MAP was significantly lower in group 2 3 and 4 h after the beginning and at the end of the operation. CVP was significantly higher in group 2 3 h after the start of the operation. The total dose of fentanyl, flunitrazepam and droperidol administered was higher in group 1 than in group 2 (P less than 0.05). The duration of postoperative ventilation was similar in both groups.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1989

[An increase in intracranial pressure following fentanyl].

We report an unusual fentanyl-induced reaction in an 8-year-old boy who had to be sedated and hyperventilated because of a severe head injury. Following the intravenous administration of a bolus of fentanyl, the intracranial pressure rose markedly for about 10 min. Simultaneously, the arterial blood pressure fell and heart rate increased, critically reducing the cerebral perfusion pressure temporarily. This reaction could be due to histamine-induced vasodilation.

Child↗
PubMed1988

[Etomidate versus etomidate and hydrocortisone for anesthesia induction in abdominal surgical interventions].

The imidazole derivative etomidate has been shown to block (reversibly) adrenocortical steroid synthesis. Long-term sedation with etomidate has been associated with adrenocortical insufficiency and increased mortality in severely ill patients. The significance of adrenocortical blockade after a single induction dose of etomidate remains a matter of debate. This study was designed to analyze the role of glucocorticoid deficiency after a single induction dose of etomidate for major surgery. In a prospective controlled double-blind study, 20 consecutive patients scheduled for colorectal surgery were randomly allocated to either hydrocortisone substitution or placebo (glucose 5%). Hydrocortisone was given as a continuous infusion in a dose of 100 mg dissolved in 5% glucose over 10 h. We combined general anesthesia and epidural anesthesia (L3-4) using bupivacaine (0.5%). Induction of anesthesia: etomidate (0.2-0.3 mg/kg), fentanyl (0.1-0.2 mg), pancuronium (2 mg), and succinyl-choline (1.0-1.5 mg/kg), with endotracheal intubation and mechanical ventilation. Anesthesia was maintained at N2O/O2 2:1 and fluothane (0.4-0.6 vol%). At the end of surgery patients were extubated after oxygenation. In all patients blood pressure, heart rate, central venous pressure, and ECG were monitored continuously, both intra- and postoperatively. During induction, patients received 1,000 ml 0.9% NaCl, followed by continuous administration of 0.9% NaCl, 6 ml/kg per hour intraoperatively and 40 ml/kg per 24 hours post-operatively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Insufficiency↗
PubMed1987

[Atropine in intraoperative isorhythmic AV dissociation].

40 patients of the ASA groups I and II in whom intra-operatively an isorhythmic AV dissociation occurred under inhalation narcosis with halothane or enflurane, were examined in a randomized study. Within an observation period of 15 minutes the spontaneous rate of return to the sinus rhythm was 20 per cent (group A, n = 20). Intravenous administration of 0.01 mg/kg atropine sulphate produced a significantly higher rate of return of 80% within the same period. On the whole, no influence on arterial blood pressure was noted. Atropine increases the heart rate by 32%, and this is considered to be an important drawback. The possibility of influencing the AV dissociation via atropine points to the pathogenetic importance of the vagus in so far as it acts as a depressant on the sinus node.

Adolescent↗
PubMed1987

[Involvement of the growth hormone in rapid increases of the potassium concentration of the serum].

As a rule, the infusion of arginine hydrochloride is followed by an increase in serum potassium. The investigation is concerned with the short-term effect of growth hormone, which can be stimulated by arginine (0.6 g/kg body weight), on potassium concentrations in rats and patients with cerebral death. The administration of human somatotropin causes a significant rise in potassium concentrations in patients with cerebral death (0.4 IU/kg body weight) and in rats (4.0 IU/kg body weight). In comparison, the infusion of arginine hydrochloride will produce only a slight increase in serum potassium in both hypophysectomized rats and patients after cerebral death. Four of the ten animals even exhibited decreases in serum potassium content. Investigations of the cationic property of arginine are used to interpret the potassium increases in the extracellular space. The transport of amino acids through the cell membrane, which can be affected by somatotropin, is put forward as a further explanation. All findings are based on measurements carried out 10-30 min after termination of the infusion.

Anesthesia↗
PubMed1987

[Continuous block of the celiac plexus].

We describe a new method for the insertion of an indwelling catheter into the region of the celiac ganglion in order to achieve long-lasting pain relief. A simple nylon catheter, of the type usually used for performing epidural catheter techniques, is placed into the prevertebral space opposite the first lumbar vertebra. The applications of the catheter were tested in a prospective study. Catheter insertion was performed in five patients suffering from carcinoma or pancreatitis. The catheter remained in place for an average of 5.8 days. The new technic was found to be successful not only for pain therapy but also to be a useful supplement for anaesthesia during laparotomy.

Adult↗
PubMed1987

[What is the benefit of subglottic suction?].

Bronchopulmonary infections are the main cause of morbidity and mortality in intensive care wards. Since the usual anatomical and physiological barrier is missing in the intubated patient, oropharyngeal secretion will reach the subglottic space between glottis and upper rim of the low-pressure cuff. Starting from there, continuous microaspiration between cuff and tracheal mucosa leads to bacterial contamination of the upper respiratory tract. In patients with a disturbed immune system from that point on colonization and infection may follow. Therefore one is called upon to search for measures to prevent infection in ventilated patients. Selective decontamination of oropharynx and gastrointestinal tract has been described as an effective method. Others are recommending the application of aminoglycosides in the tracheobroncheal system. Removing retained secreted material is a general surgical principle. Therefore we tested the practicability and effectiveness of a continuous subglottic drainage. At this point we are mainly interested in its clinical aspects and in the method. We investigated the subglottic drainage in 10 intensive care patients who were on long-term mechanical ventilation and had undergone tracheostomy. All patients had an Ultratracheoflex cannula Nr. 9-11 (Rüsch Company, West Germany). It was modified by a suction catheter Ch. 12 (Uno Plast Company, West Germany): We cut two additional small holes in the curved catheter tip and attached the catheter with this part above the cuff at the dorsal convexity to the tracheoflex cannula (see illustration 1). An infusion pump was used for suctioning secretion from the subglottic space by an ordinary infusion set and at a suction flow of 100-125 ml/h.(ABSTRACT TRUNCATED AT 250 WORDS)

Critical Care↗
PubMed1987

["Self-taming": an alternative to the prevention of succinylcholine-induced pain].

Muscle pain associated with single-bolus administration of suxamethonium is reported to be one of the common complications of this technique. Since suxamethonium is the most commonly used relaxant in our department and priming with nondepolarizing muscle relaxants is also reported to be linked with complications, while the literature concerning this problem is very contradictory, we wondered if the so-called "self-taming" method represents an alternative to pretreatment with nondepolarizing muscle relaxants. One hundred thirty-two patients (69 male, 63 female) were randomly allocated to three groups. Anesthesia was induced with thiopentone 7 mg/kg body weight. Group 1 (n = 44) was pretreated with 2 mg pancuronium bromide 3 min prior to full relaxation with suxamethonium 1.5 mg/kg. Group 2 (n = 43) received no pretreatment. Group 3 (n = 45) received 4 mg suxamethonium i.v. after induction. One minute later the remaining dose of suxamethonium was applied ("self-taming"). Muscle fasciculation and postoperative myalgia were verified by means of a score. Neuromuscular transmission was recorded on a monitor after controlled train-of-four stimulus and time of onset of neuromuscular blockade was measured. With regard to muscle fasciculation, postoperative pain, and onset of neuromuscular blockade, "self-taming" with suxamethonium yielded results identical to pretreatment with pancuronium bromide. It may therefore be considered as an alternative to pretreatment with nondepolarizing muscle relaxants.

Adult↗
PubMed1987

[Pindolol in intraoperatively developing isorhythmic AV dissociation].

The pathogenetic mechanism of isorhythmic AV dissociation (ID)--the often so-called nodal rhythm--developing during anesthesia is unclear. It has been proposed that stimulation of the AV node is caused by elevated sympathetic tone and a simultaneous blockade of the sinus node. In our prospective, randomized study the effect of the beta-blocking agent pindolol in converting ID into normal sinus rhythm has been investigated. Methods. Fourty patients (27 men, 13 women) aged 17 to 81 years, ASA class I and II, who developed ID during an elective surgical procedure were divided into four equal, randomized groups. The biometric data, type of operation, and anesthesia technique were comparable: induction of anesthesia with thiopental, intubation, and continuation with N2O/O2 combined with halothane or enflurane. The patients in group A formed the control group. The other patients received pindolol in a dose of 0.5 (group B), 1.0 (group C), and 2.0 (group D) micrograms/kg over a period of 30 s intravenously. The frequency of restoration of sinus rhythm during a testing period of 15 min in the pindolol-treated patients was compared with the frequency of the spontaneous converting rate in the control group. Results. A spontaneous return to sinus rhythm occurred in 2 of 10 (20%) patients of the control group, whereas with pindolol the restoration of sinus rhythm was effected in 25 of 30 (83.3%) patients during the observation period of 15 min (p less than 0.001). The dose of 2.0 micrograms/kg pindolol (group D) was most effective.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

Epidural catheters of the multi-orifice type: dangers and complications.

A study on epidural catheters of the multi-orifice type, investigating their tendency to epidurovasal (with an intravascularly positioned catheter tip) and epidurosubarachnoid (with the catheter tip inserted in the subarachnoid space) malpositioning, was conducted on 113 patients using clinical and radiological criteria as controls. Of the improperly placed catheters, 13 were in an epidurovasal (11.5%) and one was in an epidurosubarachnoid (0.9%) position. The findings demonstrate the occasional hazardous dual compartmental misplacement of multi-orifice catheters, in which a distal opening can lie intravascularly or within the subarachnoid space, while a proximal orifice simultaneously retains normal access to the epidural space. The insufficiency of controlling or even recognizing such improperly placed catheters which are only partially in the epidural space, as well as the danger of causing a secondary dural or vascular perforation with epidural catheters, is discussed. Since epidural catheters of the multi-orifice type apparently represent an inherent, vital danger due to their construction (regardless of the catheter material and workmanship), they should no longer be used.

Aged↗
PubMed1985

[Pulmonary artery perforations as typical complication in the use of Swan-Ganz catheters].

Two cases of pulmonary artery perforation are reported in association with the use of the Swan-Ganz catheter. A 71- and a 95-year-old woman were monitored by a flow-directed catheter pre- and intraoperatively. Both of them died. After taking other cases in the literature into consideration, this severe complication can be classified as "typical" for this examination technique. Possible means of prevention, diagnosis, and treatment of these complications are discussed. A review of incidence and genesis is given.

Aged↗
PubMed1985

[Collecting end-expiratory air for capnography in high-frequency jet ventilation].

By means of an ejector attachment to the endotracheal tube a negative intratracheal pressure of approx. -1 mmHg is created during an interruption of HFJV. Within 4 to 10 sec. this suction supplies alveolar air to the distal end of the endotracheal tube where capnographic analysis is possible in the mainstream or bystream. The end-tidal pCO2 differs by 0.1 mmHg (mean) from the arterial carbon dioxide partial pressure with a highly positive correlation (R = 0.98).

Carbon Dioxide↗
PubMed1985

[Introduction of an insertion aid for nasal intubation].

Naso-tracheal intubation can lead to complications. We describe a device for protecting the nasal passage and preventing a false passage. Clinical studies show that this significantly reduces the incidence of bleeding, mucosal damage, failure and mucosal erosion.

Catheterization↗
PubMed1984

[Animal experiment studies of chronic thiamine deficiency. Changes in carbohydrate and amino acid metabolism under resting and load conditions].

The metabolic effects of thiamine deficiency on the metabolism of lactate, acid-base and amino acids were evaluated both with and without muscular exercise in a controlled animal experiment. Thiamine deficiency - in good correlation with its biologic halftime and also with reports in the literature - caused with a latency of 17-56 days and statistically proven in parallel the following effects: hyperlactemia; in comparison to controls elevated plasma concentrations of threonine, alanine, glutamic acid, glutamine, histidine, methionine, taurine, valine, isoleucine and leucine; distinctly lowered - also in comparison to controls - plasma concentrations of arginine and tryptophan. Furthermore, in the thiamine deficient rats predetermined muscular exercise caused the following effects, also occurring concomitantly: life threatening lactacidosis; marked - statistically prover - disturbance of the homeostasis of alanine, glycine, methionine and arginine; distinctly - and statistically significant - elevated plasma concentration of proline; statistically significantly lowered plasma concentrations of taurine. The reasons for all these changes under thiamine deficiency is most likely a metabolic one primarily due to a disturbance of the utilization of pyruvate in the liver. An additional disturbance of both the transsulfuration pathway and the Krebs-Henseleit-cycle seems probable. The physiologic regulation of pyruvate, lactate, alanine, serine and tyrosine during muscular exercise in correlation to the controls is being discussed.

Amino Acids↗