[Silexan and narcosis : case report and possibilities of preoperative and perioperative management]. / Silexan und Narkose : Fallbericht und Möglichkeiten des prä- sowie perioperativen Managements.

The increased use of phytotherapeutic drugs means that anesthetists are more often confronted with these drugs. In this case report possible problems which can occur are demonstrated exemplified by silexan. Silexan is a phytotherapeutic anxiolytic which is used in anxiety disorders. Because of its potential mechanism of action via the neurotransmitter gamma-aminobutyric acid (GABA) receptors interactions with narcotic drugs are possible. The case of an 18-year-old girl who underwent an operation under general anesthesia while taking silexan as long-term medication is presented. The desired depth of narcosis could only be reached by inhalative induction with sevoflurane after unsuccessful induction attempts using intravenous propofol and thiopental. Possible explanations for this route and inhalative induction as a possible alternative are discussed.

Intraocular pressure more reduced during anesthesia with propofol than with sevoflurane: both combined with remifentanil.

BACKGROUND: Short-acting anesthetic agents are suitable and commonly used in ocular surgery. Propofol and remifentanil are known to reduce intraocular pressure (IOP), but no information is available regarding the effects of sevoflurane combined with remifentanil on IOP. METHODS: Therefore, a prospective, randomized study was conducted to compare the effects on IOP of two different anesthetic techniques: one based on a total intravenous anesthesia with propofol (Group P, bolus 1.5-2.0 mg/kg, maintenance 3.0-7.0 mg/kg/h); and the other based on sevoflurane (Group S, inhalational induction, end-tidal concentration 0.7-1.2 vol.%). An infusion of remifentanil (10 microg/kg/h) was used with both techniques. In ASA I-III patients with normal IOP undergoing elective cataract surgery, using an applanation tonometer, IOP was measured contralateral to the operated eye at nine predefined time points before, during and after anesthesia. RESULTS: The two groups (n=20 each) were comparable with regard to demographic data and hemodynamic variables. Baseline IOP was 14.2+/-2.8 mmHg (Group P) and 14.1+/-2.4 mmHg (Group S; NS). During and following the induction of anesthesia, IOP was reduced in both groups. Intraocular pressure was significantly lower in Group P (6.0+/-3.2 mmHg) than in Group S (8.9+/-3.4 mmHg) during the induction of anesthesia. CONCLUSION: In patients undergoing cataract surgery under general anesthesia with tracheal intubation, anesthetic regimens with propofol as well as with sevoflurane, both combined with remifentanil, decrease IOP significantly. The decrease in IOP was significantly more pronounced in the propofol group than in the sevoflurane group.

Immunomodulating effects of surgical intervention in tumors of the head and neck.

The immunomodulating effect of primary surgical intervention in 33 patients with squamous cell carcinoma of the oral cavity, pharynx, and larynx was analyzed prospectively. An operation time of longer than 7 hours was significantly associated with a decrease of total lymphocyte counts, CD4(+) T lymphocytes, and CD8(+) T lymphocytes. The CD4/CD8 ratio as a marker for the downregulation of the cellular immune response was slightly decreased but still in the normal range. CD4(+) lymphocyte counts increased within 7 days, and CD8(+) lymphocytes increased 4 weeks after the operation. The in vitro stimulation of the lymphocytes was impaired for 1 to 4 weeks. Release of interleukins, interferon-gamma, and tumor necrosis factor-alpha remained low despite the surgical trauma. The decreased lymphocyte counts, especially CD4(+) and CD8(+) lymphocytes, were significantly associated with duration of operation and volume of blood loss. Extension of trauma, age, type of anesthesia, and type of intensive care intervention were not associated with specific immunomodulating effects. However, these factors might be responsible for suppression of the immune system, which is expressed by lymphocyte depletion, lymphocyte dysfunction, and impaired upregulation of cytokine secretion.

Image guided excision of a ruptured feeding artery "pedicle aneurysm" associated with an arteriovenous malformation in a child: case report.

Excision of a ruptured aneurysm located at a lenticulostriate feeding artery associated with an arteriovenous malformation was performed using image guided neuronavigation in an 8-year-old child. The management of this lesion, which is rare in childhood, demonstrates the potential of combining frameless stereotaxy for precise target approach with conventional open microneurosurgery to minimize morbidity. Because of the unavoidable shifting of the brain that occurs during surgery, a catheter pointing towards the dome of the aneurysm was placed using image guidance prior to insertion of spatulae.

[Behavior of intraocular pressure in anesthesia with isoflurane in comparison with propofol/alfentanil]. / Verhalten des intraokularen Druckes unter Anästhesie mit Isofluran im Vergleich zu Propofol/Alfentanil.

AIM: To investigate the influence of isoflurane anaesthesia versus total intravenous anaesthesia with propofol/alfentanil on intraocular pressure (IOP). METHODS: 40 patients undergoing ophthalmic surgery were randomly allocated to two study groups. In group 1 (n = 20), anaesthesia was induced with thiopentone 4 mg/kg and alfentanil 15 micrograms/kg. Maintenance of anaesthesia was achieved with isoflurane 0.5-0.8 Vol.% and 70% nitrous oxide in oxygen. Patients in group 2 (n = 20) received propofol 1.5 mg/kg, which was followed by a continuous infusion of 6 mg/kg/h. In addition, alfentanil 15 micrograms/kg was administered, followed by a continuous infusion of 15 micrograms/kg/h. In both groups, endotracheal intubation was facilitated by succinylcholine 1 mg/kg, and further muscle relaxation was achieved with vecuronium 0.07 mg/kg. Measurements of IOP using an applanation tonometer were taken in each patient at 10 different time points. RESULTS: In both groups, there was a significant decrease in IOP after induction of anaesthesia. No significant differences in IOP occurred between groups, with patients in group 2 showing a trend towards lower IOP values. CONCLUSION: We conclude from our results that both anaesthetic techniques can be administered if increases in IOP have to be avoided.

Comparative effects of atracurium and vecuronium on intraocular pressure.

The non-depolarising muscle relaxants atracurium and vecuronium have been found to exert variable effects on intraocular pressure (IOP). The aim of the present study was to assess the influence of atracurium and vecuronium on IOP under standardized clinical conditions. A total of 40 patients undergoing ophthalmic surgery were randomly allocated to 2 study groups. Following oral premedication with dipotassium clorazepate (0.3 mg/kg), anaesthesia was induced with thiopentone (3-4 mg/kg) and alfentanil (15 micrograms/kg). Muscle relaxation was provided according to randomisation, with patients in group 1 receiving 0.3 mg/kg atracurium and patients in group 2 0.07 mg/kg vecuronium. Anaesthesia was maintained with isoflurane (0.5-0.8 vol%) and 70% nitrous oxide in oxygen. The trachea was intubated 4 min after induction and muscle relaxation. A total of nine measurements of IOP were taken in each patient, starting before premedication and ending 5 min after endotracheal intubation. In both groups, there was a significant decrease in IOP after induction of anaesthesia with thiopentone, alfentanil, and atracurium or vecuronium. No difference in IOP was found between the groups. We conclude that both muscle relaxants can be given when increases in IOP have to be avoided.

Evoked potential monitoring during repeatedly induced ventricular fibrillation for internal defibrillator implantation.

Repeated induction of ventricular fibrillation (VF) with circulatory compromise during implantable cardioverter defibrillator (ICD) testing may cause cerebral injury. To test this hypothesis, somatosensory evoked potentials (SEP), a more sensitive marker of injury, were recorded in patients (N = 10) undergoing ICD implantation. SEP were recorded before induction of anesthesia, after induction of anesthesia, before and at several times following induction of VF. Possible modifying factors of the SEP measurements such as anesthetic application, blood pressure, body temperature, and hematocrit remained constant throughout the operations. Central conduction time was unaffected by ICD defibrillation testing. Amplitude of SEP primary complexes was transiently reduced at 34.9% (P < 0.01) by defibrillation testing, but returned to control within 10 minutes after testing. It is concluded that while ICD defibrillation testing may produce transient changes in SEP, there is no evidence of residual cerebral injury.

Hemodynamic and respiratory effects of pneumoperitoneum and PEEP during laparoscopic pelvic lymphadenectomy in dogs.

Extended laparoscopic operations are being performed increasingly in high-risk patients. To assess the effects of increased intraabdominal pressure (IAP) and positive end-expiratory pressure (PEEP) on the hemodynamic and respiratory system during extended procedures a carbon dioxide pneumoperitoneum was artificially induced in 10 dogs undergoing laparoscopic pelvic lymphadenectomy. An increase in IAP up to 15 mmHg had no negative effect on the cardiovascular system. However, the combination of an increased IAP (10-15 mmHg) with PEEP (8 cmH2O) markedly depressed the hemodynamic variables. Measurement of arterial carbon dioxide and fractional end-tidal carbon dioxide revealed significant CO2 retention. We conclude from the results that laparoscopic pelvic lymphadenectomy should be performed in high-risk patients only under general anesthesia with expanded cardiopulmonary monitoring.

[Cognitive function of geriatric ophthalmology patients after local and general anesthesia]. / Untersuchung der kognitiven Funktion bei geriatrischen ophthalmologischen Patienten nach Lokal-bzw. Allgemeinanästhesie.

Since there will be an increase in the number of geriatric patients who undergo surgery and anesthesia over the next few years, studies comparing the effects of general and local anesthesia on cognitive functioning in elderly persons are mandatory. One hundred eleven ophthalmological patients, all over the age of 64 years, were assessed preoperatively, on the first and on the fourth postoperative day using a battery of standardized cognitive tests. Of the initial sample, 47 patients undergoing local and 54 undergoing general anesthesia completed the assessment. The performance of the patients in six tests did not change perioperatively. In both anesthesia groups, two tests revealed a cognitive deficit postoperatively, which only became evident on the first postoperative day. The two other tests showed a significant difference between the two anesthesia groups on the first postoperative day. The performance of patients with general anesthesia decreased transiently and returned to the initial levels within 3 days. We conclude from our results that postoperative cognitive deficits may occur in geriatric patients. However, general anesthesia poses no more risk to cognitive function than local anesthesia.

Oral clonidine premedication prevents the rise in intraocular pressure following succinylcholine administration.

The objective of the study was to assess the effects of premedication with clonidine on intraocular pressure (IOP) after the administration of succinylcholine. Fifty elderly patients undergoing ophthalmic surgery were randomly allocated to two study groups. Group 1 patients (n = 25) received clonidine, 300 micrograms p.o. In group 2 (n = 25), the benzodiazepine dipotassium clorazepate was given p.o. at a dose of 0.3 mg.kg-1. Anesthesia was induced with thiopental 3-4 mg.kg-1, alfentanil 10 micrograms.kg-1, atracurium 0.07 mg.kg-1, and succinylcholine 1 mg.kg-1. Nine IOP measurements were taken in each patient starting before premedication and ending 3 min after endotracheal intubation. In both groups, there was a decrease in IOP after induction of anesthesia with thiopental and alfentanil. Succinylcholine administration and endotracheal intubation had no further effect on IOP in the clonidine group. In group 2, succinylcholine caused an increase in IOP when compared with the post induction value. We conclude that clonidine premedication can prevent the increase in IOP following succinylcholine administration.

[Suture fixation of a Swan Ganz catheter to the left brachiocephalic vein during re-thoracotomy]. / Nahtfixation eines Swan-Ganz-Katheters an die V. brachiocephalica sinistra bei Rethorakotomie.

This case report describes the intraoperative fixation of a Swan-Ganz catheter at the left brachiocephalic vein by a suture during rethoracotomy in a cardiac surgical patient. In case of a rethoracotomy by median sternotomy the right-sided veins should be preferred for the insertion of a Swan-Ganz-catheter. Furthermore the free mobility of the catheter should be controlled before closure of the thorax.

Effects of thiopentone/suxamethonium on intraocular pressure after pretreatment with alfentanil.

The effects of pretreatment with alfentanil on intraocular pressure (IOP) were investigated in 40 patients undergoing ophthalmic surgery. Patients were randomly allocated to two study groups. Group 1 patients (n = 20) received alfentanil 15 micrograms.kg-1, vecuronium 0.01 mg.kg-1, thiopentone 3-4 mg.kg-1, and suxamethonium 1 mg.kg-1 for anaesthetic induction, whereas patients in group 2 (n = 20) received vecuronium 0.01 mg.kg-1, thiopentone 3-4 mg.kg-1, and suxamethonium 1 mg.kg-1. A total of seven measurements of intraocular pressure were taken in each patient, starting before premedication and ending after extubation of the trachea. In group 2 patients, there was an increase in IOP after endotracheal intubation. In group 1 patients, a decrease in IOP occurred which was related to the decrease in arterial blood pressure. We conclude that alfentanil pretreatment can prevent the increase in IOP following suxamethonium administration.

Hazards of high dose barbiturate therapy in head-injury patients.

Despite of controversial findings, High-Dose-Barbiturate Therapy is advocated by many authors for treatment of postischemic/anoxic encephalopathy and head trauma with elevated intracranial pressure. The adverse effects to thiopentone are analyzed in a retrospective study including 30 patients treated by high-dose thiopentone for raised intracranial pressure after severe head injury. The pathophysiology and occurrence of clinical complications in many systems of the organism are illustrated. The specific prevention measures and the extended monitoring of barbiturate-treated patients are described. Considering the high incidence of clinical complications the indication for HDBT has to be reevaluated.