Pulmonary embolism and myocardial hypoxia during extracorporeal membrane oxygenation.

The treatment of a newborn with severe meconium aspiration by venoarterial extracorporeal membrane oxygenation (ECMO) was complicated by myocardial hypoxia with a marked decrease of myocardial contractility. The onset of the cardiac hypoxia was related to a pulmonary artery embolus. The origin of the embolus was a deep femoral vein thrombosis, caused by a central vein catheter, which was inserted 1 day before ECMO by venous cutdown. The possible pathophysiology of myocardial hypoxia in this patient is discussed, especially with regard to myocardial perfusion, supporting the hypothesis of coronary perfusion occuring with blood from the left ventricle and not from the arterial cannula in the aorta.

Laryngo-pharyngeal complaints following laryngeal mask airway and endotracheal intubation.

STUDY OBJECTIVE: To investigate the incidence and severity of laryngo-pharyngeal complaints following anesthesia with the use of a laryngeal mask airway (LMA) compared with endotracheal intubation in adults. DESIGN: Prospective study with randomized patient selection. SETTING: University medical center. PATIENTS: 202 adult ASA physical status I, II, and III patients scheduled for elective surgery of either an extremity or breast, or a transurethral resection. INTERVENTIONS: Following intravenous induction of anesthesia, a standard LMA size #3, #4, or #5 corresponding to the patient's body weight, was inserted in 103 patients; 99 patients were intubated with a polyvinylchloride endotracheal tube [7.5 mm inner diameter (ID) in women and 8.0 mm ID in men]. Cuff pressures in the LMA group were initially reduced to a minimum pressure at which an air-tight seal between the LMA and the laryngeal inlet was provided at a positive pressure of 20 cm H2O during manual bag ventilation. Cuffs of endotracheal tubes were inflated and controlled to a volume needed to prevent gas leak at 35 cm H2O pressure. MEASUREMENTS AND MAIN RESULTS: Cuff pressures were continuously monitored in both groups. Patients assessed their laryngo-pharyngeal complaints on a 101-point numerical rating scale on the evening after surgery and the following two days. No difference was found in the incidence and severity of sore throat on the evening following surgery or on the two following days. Dysphonia was more frequent following intubation than following LMA insertion on the day of surgery (46.8% vs. 25.3%) and on the first postoperative day (28.1% vs. 11.6%) (p < 0.05). However, the incidence of dysphonia increased with the duration of anesthesia in LMA patients but not in intubated patients. The incidence of dysphagia was significantly higher following LMA insertion compared with endotracheal intubation on the day of surgery (23.8% vs. 12.5%), and on the first postoperative day (22.3% vs. 10.4%). The severity of the individual complaints of minor laryngo-pharyngeal morbidity was comparable between groups. The type of airway management during anesthesia did not affect patient satisfaction with the anesthesia received. CONCLUSIONS: There is a distinct pattern of laryngo-pharyngeal complaints following the use of the LMA and endotracheal intubation. With regard to minor laryngo-pharyngeal morbidity, the advantage of the LMA to endotracheal intubation is questionable.

Distinct central anticholinergic syndrome following general anaesthesia.

The purpose of this prospective study was to identify the incidence of a distinct central anticholinergic syndrome following routine anaesthesia. For 2 months, all inpatients aged more than 15 years scheduled for elective procedures and cared for in the recovery room were investigated for symptoms of the syndrome. Patients with neuropsychiatric disease or other disorders that could alter consciousness were excluded. Prolonged action of anaesthetics or relaxants, respiratory depression and metabolic disorder were ruled out before making the diagnosis. Out of 962 patients (366 men, 596 women), 18 (4 men, 14 women) developed the syndrome. The difference between men and women was not statistically significant. Six out of 60 women developed the syndrome after a hysterectomy with or without adnectomy/oophorectomy, and this high incidence was significantly different from that observed after all other procedures in women (P = 0.003) or all other gynaecological procedures (P = 0.013). The reason for this is unknown. In six of the 18 cases, untreated prolonged somnolence lasted for more than 2 h. All patients woke up after an injection of physostigmine, but six of them relapsed into somnolence and needed a second, and in one case a third, injection. The findings of the study emphasize that, when there is delayed recovery from anaesthesia, the diagnosis of central anticholinergic syndrome should be considered if other accessible causes for that condition have been excluded.

Marked increases in heart rate associated with sevoflurane but not with halothane following suxamethonium administration in children.

The changes in heart rate and arterial blood pressure following the administration of suxamethonium in healthy children (mean age 3.8 +/- 0.3 years) during inhalational induction with either sevoflurane (n = 22) or halothane (n = 19) were studied. Heart rate 60s following suxamethonium administration increased significantly in the sevoflurane but not in the halothane group. In the halothane group, four children required intravenous (i.v.) atropine as as result of bradycardia. None of the children in the sevoflurane group developed bradycardia following suxamethonium (P < 0.05). Values of oxygenation, ventilation and age corrected minimal alveolar concentration were comparable at all measurement times. The haemodynamic response to the administration of suxamethonium in children anaesthetized with sevoflurane seems to reflect the stimulation of the autonomic ganglia by suxamethonium whereas this positive chronotropic effect is attenuated or reversed by halothane.

[Intubation trauma of the larynx--a literature review with special reference to arytenoid cartilage dislocation]. / Intubationstraumen des Larynx--eine Literaturübersicht unter besonderer Berücksichtigung der Aryknorpelluxation.

Trauma to the cricoarytenoid joint represents a rare but serious complication of endotracheal intubation. Subluxation and luxation of the arytenoid cartilage may occur during difficult but also following uncomplicated intubation. Forces on the arytenoid cartilage exerted by the laryngoscope blade or by the distal part of the endotracheal tube may cause anterior and inferior displacement of the arytenoid cartilage. Due to the conventional intubation technique the left arytenoid cartilage is affected most frequently. Posterolateral subluxation is attributed to the pressure exerted on the posterior glottis by the convex part of the shaft of the tube. Systemic diseases (e.g. terminal renal insufficiency, bowel diseases, acromegaly) may cause degeneration of the cricoarytenoid ligaments, thus making the cricoarytenoid joint more susceptible to traumatic dislocation. Persisting alterations of voice, sore throat and pain on swallowing may hint to the diagnosis of arytenoid dislocation. However, stridor and shortness of breath have also been observed. If pharyngo-laryngeal complaints persist, evaluation by laryngologists is mandatory. In addition to indirect and direct laryngoscopy, computerised tomography and electromyography of the larynx play an important role in differentiating arytenoid dislocation from true vocal cord paralysis due to nerve damage. Early operative reposition results in fair prognosis, whereas delayed diagnosis may lead to ankylosis of the cricoarytenoid joint with permanent impairment of the voice and possibly compromised airway protection.

A comparison of sevoflurane with halothane in outpatient adenotomy in children with mild upper respiratory tract infections.

STUDY OBJECTIVE: To investigate the efficacy and safety of sevoflurane compared with halothane in pediatric outpatient ear-nose-throat (ENT) surgery during the induction, maintenance, emergence, and recovery of anesthesia. DESIGN: Prospective, randomized, comparative, open-label study. SETTING: ENT operating room and postoperative recovery room at a university medical center. PATIENTS: 41 ASA status I and II children between the ages of 2 to 10 years, with mild upper respiratory tract infection (URI). INTERVENTIONS: Induction and maintenance of anesthesia with either sevoflurane or halothane for outpatient adenotomy, otomicroscopy, and myringotomy. MEASUREMENTS AND MAIN RESULTS: Induction (means +/- SEM) was significantly shorter in the sevoflurane group (2.6 +/- 0.2 minutes) than in the halothane group (3.2 +/- 0.2 minutes). There was no difference between the two groups with regard to complications that occurred during the induction and maintenance period. The time to emergence and recovery was significantly shorter with sevoflurane than with halothane (means +/- SEM; time to extubation 9.9 +/- 0.98 minutes vs. 13.4 +/- 1.06 minutes, time to eye opening 12.9 +/- 1.6 minutes vs. 24.5 +/- 1.8 minutes, command response time 20.7 +/- 2.5 minutes vs. 36.4 +/- 2.8 minutes). No difference in the incidence of complications during emergence and recovery was found. Evaluation of recovery as assessed by a modified Aldrete score showed that children who had received sevoflurane reached higher scores in the first 30 minutes following the discontinuation of the anesthetic. The Pain/Discomfort Scale demonstrated a difference in the sevoflurane group, with more children being agitated and restless. CONCLUSION: Sevoflurane provides a safe and rapid anesthetic induction with no differences in complications during the induction, maintenance, and emergence period. With sevoflurane, the time of emergence and recovery was significantly shorter. The characteristics of sevoflurane as evaluated in the present study make it a suitable anesthetic in pediatric outpatient surgery even in the presence of mild URI.

[Intraoperative contrast echocardiography for detection of a patient foramen ovale using a provocation test and ventilation with PEEP respiration]. / Intraoperative Kontrast-echokardiographie zum Nachweis eines funktionell offenen Foramen ovale unter Durchführung eines Provokationstests mit PEEP-Beatmung.

UNLABELLED: Intraoperative paradoxical air embolism may occur even if a patent foramen ovale (PFO) is excluded by contrast transoesophageal echocardiography (TEE) under 20 cm H2O positive airway pressure. It is questionable whether the combination of PEEP and ventilation with a large tidal volume increases the sensitivity of contrast TEE in detecting a PFO. METHODS: Eighty healthy patients (ASA status I, II) scheduled for surgery in the supine position and ranging from 25 to 72 years of age were investigated by TEE, which was performed in the biatrial viewing mode (short axis). Echocardiographic contrast (10 ml agitated gelatine solution) was injected during two different ventilation manoeuvres. Manoeuvre I: Contrast injection during the application of 20 cm H2O positive airway pressure for 5 s. The pressure was released when the right atrium became completely opacified by echo targets. The injected bolus was observed throughout the ventilatory cycle, with special attention being given to early expiration and systole. A right-to-left shunt was assumed if five echo targets were observed in the left atrium. Manoeuvre II: Contrast injection during ventilation with PEEP (15 cm H2O), a tidal volume of 1,200 ml, and a respiratory rate of 6/min. RESULTS: The frequency of a PFO causing a right-to-left interatrial shunt was 8.7% (7 cases) in manoeuvre I and 15% (12 cases) in manoeuvre II. In one case a PFO was diagnosed intraoperatively by chance. DISCUSSION: The use of provocation manoeuvres including ventilation with PEEP and high tidal volumes might improve the ability to detect a PFO presenting with right-to-left interatrial shunt by intraoperative contrast TEE, but does not have 100% sensitivity. However, our results clearly indicate that ventilation with PEEP and high tidal volumes may predispose to paradoxical embolism.

[Intraoperative airway obstruction during use of a laryngeal mask. A case report and fiber optic findings]. / Intraoperative Atemwegs-obstruktion bei Anwendung der Larynxmaske. Fallbericht und fiberoptische Befunde.

Laryngeal obstruction is a challenging complication during anaesthesia with a face mask or laryngeal mask and is due to insufficient analgesia in most cases. However, with a laryngeal mask in place it must be differentiated whether the airway obstruction is caused by the laryngeal mask itself or by other factors. Knowledge of the pathophysiology of the laryngeal closure and experience with the use of the laryngeal mask are essential for adequate treatment. Not the removal of a correctly inserted laryngeal mask which initially provided a satisfying airway, but the relaxation of laryngeal muscle activity by adequate anaesthesia is the first mandatory treatment if intraoperative airway obstruction occurs.

Feasibility and rate of leucocyte depletion with a single leucocyte depletion filter during massive transfusion.

BACKGROUND: The study examines the feasibility and rate of leucocyte depletion with a single leucocyte depletion filter in combination with the Level 1 heat exchanging infusion/transfusion device H-500/H-25i during massive transfusions. MATERIALS AND METHODS: LeukoGuard-6 filters (LG-6) were manufactured to fit the infusion sets of the Level 1 H-500/H-25i. This modified device was used intraoperatively in six patients with severe haemorrhage. Following determination of the white cell counts (WCC) in each buffy coat poor red cell concentrate prior to administration, WCC were then obtained from blood sampled directly distal to the filter after the first and after the last red cell concentrate was given. Leucocytes were determined in the Nageotte chamber and then calculated to determine leucocytes/250 ml (therapeutic unit). Parameters of feasibility (time for preparation of the system, the amount of transfused red cell concentrates, time interval of transfusions) were recorded. RESULTS: The mean volume of red cell concentrates which were transfused and filtered by a single filter was 2,708 ml (S.D. +/- 797 ml) within a mean time interval of 42.5 min (S.D. +/- 26 min). With a mean WCC of 1.17 +/- 0.68 x 10(9) leucocytes/250 ml in the red cell concentrate prior to filtration the LG-6 achieved a log-3 reduction of leucocyte counts. During the transfusion the WCC distal to the filter increased on average by a factor of 3 (from 0.9 x 10(6) leucocytes/250 ml following the first blood unit to 2.7 x 10(6) leucocytes/250 ml following the last), but remained below 5 x 10(6). CONCLUSION: Modification of the Level 1 H-500/H-25i system by incorporating the LG-6 leucocyte depletion filter provides a significant reduction of the WCC in the transfused red cell concentrates during massive transfusion. The rate of leucocyte depletion by a single leucocyte depletion filter achieves low leucocyte counts which are documented to be of therapeutical value. As the significance of leucocyte-reduced blood products for patients with haemorrhagic shock following trauma or major surgery has still to be elucidated, the presented device may be useful in the performance of future studies related to this subject.

[Extracorporeal membrane oxygenation of the newborn infant--an example of interdisciplinary project management]. / Extrakorporale Membranoxigenierung des Neugeborenen--ein Beispiel für interdisziplinäres Projektmanagement.

In the last three years an interdisciplinary ECMO (extracorporeal membrane oxygenation) team has been set up at the Free University of Berlin in the Steglitz clinic. With this form of management, newborns only a few hours or days old who present with pulmonary failure can temporarily be managed with extracorporeal oxygenation until normal lung function is restored. The set up of this ECMO team, starting with experimental training in animal models, to the bedside clinical use is discussed. The following presentation of the first four cases managed here with ECMO aims to clarify the problems which may be encountered as well as amplifying its use as a life-saving measure.

[Loss of brain stem auditory evoked potential waves I and II during controlled hypotension]. / Ausfall der FAEP-Wellen I und II während tiefer Hypotension.

For surgical removal of a malignant choroid melanoma, it is necessary to reduce systolic blood pressure to around 50-60 mmHg in order to prevent choroidal haemorrhages. However, blood pressure reduction is associated with the risk of cerebral ischaemia. We report a patient with a malignant choroid melanoma in whom waves I and II of the brainstem auditory evoked potentials (BAEP) disappeared during surgery under controlled arterial hypotension and hypothermia (31.1 degrees C). The waves could be recorded again immediately after the mean arterial pressure was increased from 48 to 77 mmHg. The oesophageal temperature had dropped by 0.3 degrees C at this time. The 2-channel electroencephalogram (EEG) showed no irregularities during this time period. A bilateral, reversible, apparently blood-pressure-dependent loss of waves I and II during arterial hypotension despite a normal EEG has to our knowledge not been previously described in the literature. The isolated loss of waves I and II with maintenance of waves III, IV, and V is unusual. The literature contains reports of acoustic neurinoma patients in whom only wave V could be recorded. This is regarded as an indication of continued impulse conduction despite the loss of waves I to IV. Others have observed a patient with temporary and reversible loss of BAEP wave I due to vasospasm of the internal auditory artery that apparently occurred during or shortly after manipulation of the internal auditory meatus. Assuming anatomic peculiarities in the blood supply to the generators of the BAEP waves, a stenosis of the basilar artery could be considered as the cause of the bilateral reversible loss of waves I and II. Another potential source could be induced hypothermia, but this does not seem very likely because the patient's temperature was 0.3 degrees C lower at the return of the waves than at their loss.

The influence of lung injury due to mechanical ventilation on the initiation of ECMO.

Before the entry criteria for extracorporeal membrane oxygenation (ECMO) are met, newborns may require aggressive mechanical ventilation which may result in lung injury. The question arises whether the presence of a pneumothorax in these infants plays a role in the prognosis. Of the 21 newborns transferred to our hospital for ECMO, 8 were treated with ECMO. 9 of the 21 newborns developed a pneumothorax with conventional ventilation and 6 of these 9 newborns subsequently required ECMO. Infants who developed a pneumothorax but did not meet ECMO criteria and remained in the oxygenation index (OI) range between 25 and 40 for more than 2 days had a poorer prognosis. If adequate oxygenation cannot be attained with acceptable mechanical ventilation and a more aggressive ventilation results in a pneumothorax, ECMO should be considered even if the oxygenation index is below 40.

Safe and normothermic massive transfusions by modification of an infusion warming and pressure device.

A fluid-warming pressure infusion device (H-500/H25i, Level 1) was modified to meet the demands for safe, normothermic, and effective massive transfusions. By incorporating an autoventing 40 microns filter (Pall AV-SP), which was originally manufactured for use in an extracorporal circulation, the risk of accidental air embolism can be eliminated. Feasibility and efficiency of this model were tested in ten patients. The mean volume transfused and infused (packed red cells and colloids) was 6750 mL (SD +/- 2519) during a mean period of acute volume resuscitation of 55 minutes (SD +/- 30). Calculated flow rates averaged 140 mL/min, which were sufficient to stabilize all but one patient. This patient subsequently died because of uncontrollable surgical bleeding. Body temperature remained stable with a minimal mean drop of -0.3 degrees C. Supplying the Level 1 warming and pressure device with a Pall AV-SP filter allows for safe, effective, and demand-adapted massive transfusions in a large number of trauma patients at a reasonable cost.

[Cardiac effects of atropine in patients treated with antidepressive medication]. / Kardiale Atropinwirkungen bei Patienten mit Antidepressiva-Medikation.

UNLABELLED: It is often suggested that atropine should be avoided in patients on treatment with tricyclic or tetracyclic antidepressants. It is feared that the strong anticholinergic side effects of these drugs could exaggerate the effects of atropine on the heart. METHODS: In a controlled prospective study, 31 patients on treatment with tri- or tetracyclic antidepressants were given atropine in incremental doses. ECG-changes and changes in heart rate were recorded and compared to a control group. Atropine 2 micrograms/kg was administered in 60 sec. intervals up to a total dose of 10 micrograms/kg. RESULTS: The patients on antidepressant treatment had a higher incidence of common anticholinergic side effects (dryness of mouth, accommodation disorders, constipation) due to the anticholinergic properties of the antidepressants. In addition, the basal heart rate of these patients was significantly higher compared to the control group (81/min vs. 73/min). After administration of 2 and 4 micrograms/kg of atropine the patients of the control group showed a 5% resp. 4% decrease in heart rate. 26% of these patients developed conduction disturbvances. These changes could be explained by the parasympathetic effect of low doses of atropine. They were less pronounced in the patients on treatment with antidepressants. Here, only the administration of 2 micrograms/kg of atropine led to a 2% decrease in heart rate. Only 6% of these patients developed conduction disturbances. Both groups showed an increase in heart rate when higher doses of atropine were administered (8 and 10 micrograms/kg). However, the increase in heart rate after administration of 10 micrograms/kg was significantly less in the patients on antidepressant treatment compared to the control group (11.4% vs. 16.2%). There were no changes of blood pressure during these investigations. CONCLUSION: The results of this study suggest that the anticholinergic properties of tri- and tetracyclic antidepressants include an increase in basal heart rate, but do not render the heart more susceptible to the cardiac effects of atropine.

[Intraoperative transesophageal versus preoperative transthoracic contrast echocardiography. A method for detection of patent foramen ovale in neurosurgical patients]. / Intraoperative transösophageale versus präoperative transthorakale Kontrast-Echokardiographie. Eine Methode zum Nachweis eines funktionell offenen Foramen ovale bei neurochirurgischen Patienten.

Preoperative detection of a patent foramen ovale (PFO) may be achieved employing either transthoracic echocardiography (TTE) with the Valsalva manoeuvre in the awake patient or trans-oesophageal echocardiography (TEE) in the anaesthesised patient. Our study was undertaken to validate these methods with regard to their efficacy in identifying patients at risk for paradoxical air embolism (PAE). METHODS. In 67 patients ranging from 28 to 70 years of age, TTE was performed utilising the Valsalva manoeuvre prior to surgery. The patients were informed about all procedures and agreed to take part in the study. After induction of anaesthesia the patients were evaluated with TEE in the supine and sitting positions. At end-inspiration 10 ml agitated gelatine solution (Gelafundin) was injected through a central venous catheter into the right atrium after airway pressure of 20 cm H2O had been maintained for 5 s. The injected bolus was observed throughout the ventilatory cycle, with special attention being given to early expiration and systole. A right-to-left shunt was assumed if five echo targets were observed in the left atrium. RESULTS. The prevalence of PFO detected by TTE/Valsalva was 9%. The diagnosis was confirmed by TEE in 2 patients in the supine and 1 in the sitting position. An echocardiogram in these patients showed bulging of the septum to the left, which was not seen in those patients in whom PFO was detected only by TTE. DISCUSSION. The reason for the lower incidence of PFO detected by TEE during airway pressure 20 cm H2O may have been an insufficient increase of pressure in the right atrium with a negative right-to-left atrial pressure gradient. A standardised ventilation manoeuvre with supra-atmospheric airway pressure of 20 cm H2O is not sufficient. Bulging of the intra-atrial septum from right to left during airway pressure is a possible indication of the efficacy of the manoeuvre, regardless of the influence of the breathing pattern.

[The relevance of CDT (carbohydrate-deficient transferrin). Preoperative diagnosis of chronic alcohol abuse in intensive care patients following elective tumor resection]. / Der Stellenwert des kohlenhydratdefizienten Transferrin (CDT). Präoperative Diagnostik des chronischen Alkoholabusus bei intensivmedizinischen Patienten nach elektiver Tumorresektion.

The increase of alcoholism-related problems is associated with vital postoperative clinical complications in chronic alcohol abusers. In particular, the alcohol withdrawal syndrome (AWS) may provoke potentially life-threatening complications in alcohol-dependent patients. Hence, a precise diagnosis of alcohol dependence is mandatory preoperatively, requiring an extensive case history using alcoholism-associated questionnaires. Additional new biological markers for detecting alcoholism could improve the accuracy of preoperative diagnosis. Carbohydrate-deficient transferrin (CDT) reflects increased alcohol consumption. The aim of our interdisciplinary study was to investigate whether the validity of the preoperative diagnosis of chronic alcohol abuse might be improved by measuring CDT. METHODS. A total of 45 patients from the departments of Otorhinolaryngology, Maxillofacial Surgery, and Abdominal and Thoracic Surgery were included in our prospective clinical study. Patients underwent resection of malignant oral, pharyngeal, laryngeal, or oesophageal tumours and were transferred to the intensive care unit for postoperative management. Routine preoperative history, examinations, and laboratory tests including GGT, MCV, ASAT, and ALAT, were supplemented by a specific alcohol-related questionnaire and CDT measurement. The patients were categorised in four groups based on history and the questionnaire: continuously abstinent subjects; sober subjects for at least 7 days; chronic abusers; and dependent subjects. CDT was separated by isocratic anion exchange chromatography and quantified by turbidimetric determination. Statistical analysis was performed by the Kruskal-Wallis test. RESULTS. Preoperatively, 21 patients were at major risk for alcoholism-related complications: 12 were chronic abusers and 9 were diagnosed as dependent. CDT was significantly increased in both groups, and was pathologically elevated in 16 of the 21 patients. Sampling occurred significantly long after the last alcohol intake in the 5 patients with normal CDT values (median: 6.0 days; range: 2-12 days) compared with the 16 with pathologically elevated CDT levels (median: 1.0 day; range: 0-4 days; P = 0.002). The sensitivity of CDT elevation was 16 out of 24 (76%), the specificity 16 out of 16 (100%). Sixteen patients had no previous history of alcohol consumption (sober for at least 7 days) and 8 were definitely abstinent. Both of these groups had normal CDT values. CONCLUSIONS. CDT was a sensitive and specific marker for chronic alcohol consumption in our patient population. Since CDT is a state marker, repeated determinations might be useful to estimate a patient's drinking habits. The combination of CDT and an alcohol-related questionnaire was reliable for detecting alcohol-dependent patients preoperatively.

Venous and paradoxical air embolism in the sitting position. A prospective study with transoesophageal echocardiography.

This prospective study investigates the frequency of patent foramen ovale (PFO), venous air embolism (VAE) and paradoxical air embolism (PAE) by transoesophageal echocardiography (TOE) in neurosurgical patients operated on in the sitting position. The risk of PAE after exclusion of PFO is assessed. A PFO was identified by pre-operative TOE and VAE and PAE by continuous intraoperative TOE. Sixty-two patients were divided into two groups, 22 patients were studied in group 1 (posterior fossa surgery) and group 2 (cervical surgery) contained 40 patients. Pre-operative TOE demonstrated a PFO in 5 of the 22 patients in group 1 (23%). Patients with proven PFO were excluded from the sitting position. Two further patients of this group (12% of 17 patients), in whom a PFO had been excluded pre-operatively, nevertheless had PAE, air occurring in all cavities of the heart. In group 2 the incidence of PFO was 4 out of 40 patients (10%). No PAE was observed in this group. Three morphological types of VAE with different haemodynamic and ventilation changes were demonstrated. VAE was observed in 76% of all posterior fossa operations and in 25% of cervical laminectomies. We conclude that a pre-operative search for PFO is mandatory considering its incidence of 23% in group 1 and of 10% in group 2, and the risk of PAE. If a PFO is detected, the sitting position should be avoided. A residual risk for PAE remains despite exclusion of PFO because the reliability of TOE is limited. TOE is the method of choice for detecting VAE and PAE.

[Postoperative air embolism caused by pneumatocephalus following occlusion of the posterior fossa. A rare complication indicative of a bridging vein disruption]. / Postoperative Luftembolie durch Pneumatozephalus nach Verschluss der hinteren Schädelgrube. Eine seltene Komplikation als Hinweis auf einen Brückenvenenabriss.

Many neurosurgeons prefer the sitting position for patients undergoing surgery in the posterior fossa because of the easier access and better conditions for haemostasis. Pneumatocephalus is a possible consequence of surgery in the posterior fossa with the patient in the sitting position. When this occurs air may enter the subarachnoid space, the cisternae, the ventricular system or the subdural space; it becomes more likely when any of the following is/are present: loss of CSF, a large cavity resulting from surgery, external or internal drainage of CSF, osmotic diuresis, and hyperventilation. Distances of 1-2 cm between cranium and brain may be found. The rupture of bridging veins may cause a subsequent subdural haematoma. Air embolism due to pneumatocephalus via the same vein after closure of the cranium is in this paper for the first time. Case report. A 37-year-old man with known Hippel-Lindau disease presented for posterior fossa surgery for treatment of a haemangioblastoma of the right cerebellar hemisphere. Surgery was done with the patient in a sitting position. Apart from one short episode of air embolism without haemodynamic changes no intraoperative complications occurred. After closure of the cranium and galea an unexpected and inexplicable air embolism of 10 min duration occurred again. TEE demonstrated the air looking like a string of beads in the right atrium. As complete skin had already been closure no explanation for the air embolism could be found. The patient was positioned supine, and air was no longer detectable in the right heart after 1 min. Approximately 1 h later both pupils were dilated and unreactive to light.(ABSTRACT TRUNCATED AT 250 WORDS)

[Perioperative cardiovascular reactions and the noradrenaline plasma level in patients on chronic antidepressant medication]. / Perioperative Kreislaufreaktionen und Noradrenalin-Plasmaspiegel bei antidepressiver Dauermedikation.

UNLABELLED: It is still controversial whether the perioperative incidence of cardiovascular complications is increased in patients on chronic treatment with cyclic antidepressants (AD) and whether AD medication should be discontinued prior to surgery. METHODS. We measured perioperative cardiovascular variables in 31 patients on chronic treatment with tri- and tetracyclic AD and 31 patients without AD medication. Heart rate, blood pressure, and noradrenaline plasma concentrations were compared between the two groups at nine points in time. During induction of anaesthesia, the ECG was recorded continuously. After the administration of 0.01 mg/kg atropine i.v., all patients received opiate-supplemented enflurane anaesthesia. RESULTS: Re-uptake inhibition of noradrenaline by AD resulted in significantly higher noradrenaline plasma concentrations before and during anaesthesia in the AD-treated group. The incidence of arrhythmias, blood pressure elevations, and tachycardia was not increased in patients in AD treatment. Arrhythmias during induction of anaesthesia were seen in 6 of the AD-treated patients and 5 of the controls. Blood pressure elevations by more than 35% were seen in 10 patients on AD treatment and 8 controls. The heart rate prior to induction of anaesthesia and 2 h after the end of surgery was significantly higher in the AD-treated group. During anaesthesia the heart rate was higher at two points in time only. The incidence of tachycardia was similar in both groups. Intravenous administration of 0.01 mg/kg atropine prior to induction of anaesthesia increased the heart rate of the patients on chronic AD medication by 11.4%. This increase was significantly higher in the control group (16.2%), suggesting that patients with chronic AD treatment do not have a higher sensitivity to atropine. CONCLUSION: The elevated noradrenaline plasma levels in patients on chronic AD treatment did not result in a higher incidence of arrhythmias, blood pressure elevations, or tachycardia perioperatively. Taking these results into account, we do not consider it necessary to discontinue chronic AD medication prior to surgery in patients without cardiovascular disease.