Usability of the SedLine® electroencephalographic monitor of depth of anaesthesia in pigs: a pilot study.

To investigate the usability of the SedLine® monitor in anaesthetized pigs. Five juvenile healthy pigs underwent balanced isoflurane-based general anaesthesia for surgical placement of a subcutaneous jugular venous port. The SedLine® was applied to continuously monitor electroencephalographic (EEG) activity and its modulation during anaesthesia. Computer tomography and magnetic resonance were performed to investigate the relationship between electrodes' positioning and anatomical structures. The pediatric SedLine® EEG-sensor could be easily applied and SedLine®-generated variables collected. An EEG Density Spectral Array (DS) was displayed over the whole procedure. During surgery, the EEG signal was dominated by elevated power in the delta range (0.5-4 Hz), with an underlying broadband signal (where power decreased with increasing frequency). The emergence period was marked by a decrease in delta power, and a more evenly distributed power over the 4-40 Hz frequency range. From incision to end of surgery, mean SedLine®-generated values (± standard deviation) were overall stable [23.0 (± 2.8) Patient State Index (PSI), 1.0% (± 3.8%) Suppression Ratio (SR), 8.8 Hz (± 2.5 Hz) Spectral Edge Frequency 95% (SEF) left, 7.7 Hz (± 2.4 Hz) SEF right], quickly changing during emergence [75.3 (± 11.1) PSI, 0.0 (± 0.0) SR, 12.5 (± 6.6) SEF left 10.4 (± 6.6) SEF right]. Based on the imaging performed, the sensor does not record EEG signals from the same brain areas as in humans. SedLine®-DSA and -generated variables seemed to reflect variations in depth of anaesthesia in pigs. Further studies are needed to investigate this correlation, as well as to define the species-specific brain structures monitored by the EEG-sensor.

[The quantitative EEG in electroencephalogram-based brain monitoring during general anesthesia]. / Das quantifizierte EEG im elektroenzephalogrammbasierten Monitoring während Allgemeinanästhesie.

The electroencephalogram (EEG) is increasingly being used in the clinical routine of anesthesia in German-speaking countries. In over 90% of patients the frontal EEG changes somewhat predictably in response to administration of the normally used anesthetic agents (propofol and volatile gasses). An adequate depth of anesthesia and appropriate concentrations of anesthetics in the brain generate mostly frontal oscillations between 8 and 12 Hz as well as slow delta waves between 0.5 and 4 Hz. The frontal EEG channel is well-suited for avoidance of insufficient depth of anesthesia and excessive administration of anesthetics. This article explains the clinical interpretation of the most important EEG patterns and the biophysical background. Also discussed are important limitations and pitfalls for the clinical routine, which the anesthetist should know in order to utilize the EEG as an admittedly incomplete but clinically extremely important parameter for the level of consciousness.

Association of electroencephalogram trajectories during emergence from anaesthesia with delirium in the postanaesthesia care unit: an early sign of postoperative complications.

BACKGROUND: Postoperative delirium is associated with an increased risk of morbidity and mortality, especially in the elderly. Delirium in the postanaesthesia care unit (PACU) could predict adverse clinical outcomes. METHODS: We investigated a potential link between intraoperative EEG patterns and PACU delirium as well as an association of PACU delirium with perioperative outcomes, readmission and length of hospital stay. The risk factors for PACU delirium were also explored. Data were collected from 626 patients receiving general anaesthesia for procedures that would not interfere with frontal EEG recording. RESULTS: Of the 626 subjects enrolled, 125 tested positive for PACU delirium. Whilst age, renal failure, and pre-existing neurological disease were associated with PACU delirium in the univariable analysis, the multivariable analysis revealed the importance of information derived from the EEG, anaesthetic technique, anaesthesia duration, and history of stroke or neurodegenerative disease. The occurrence of EEG burst suppression during maintenance [odds ratio (OR)=1.86 (1.13-3.05)] and the type of EEG emergence trajectory may be predictive of PACU delirium. Specifically, EEG emergence trajectories lacking significant spindle power were strongly associated with PACU delirium, especially in cases that involved ketamine or nitrous oxide [OR=6.51 (3.00-14.12)]. Additionally, subjects with PACU delirium were at an increased risk for readmission [OR=2.17 (1.13-4.17)] and twice as likely to stay >6 days in the hospital. CONCLUSIONS: Specific EEG patterns were associated with PACU delirium. These findings provide valuable information regarding how the brain reacts to surgery and anaesthesia that may lead to strategies to predict PACU delirium and identify key areas of investigation for its prevention.

Frontal alpha-delta EEG does not preclude volitional response during anaesthesia: prospective cohort study of the isolated forearm technique.

BACKGROUND: The isolated forearm test (IFT) is the gold standard test of connected consciousness (awareness of the environment) during anaesthesia. The frontal alpha-delta EEG pattern (seen in slow wave sleep) is widely held to indicate anaesthetic-induced unconsciousness. A priori we proposed that one responder with the frontal alpha-delta EEG pattern would falsify this concept. METHODS: Frontal EEG was recorded in a subset of patients from three centres participating in an international multicentre study of IFT responsiveness following tracheal intubation. Raw EEG waveforms were analysed for power-frequency spectra, depth-of-anaesthesia indices, permutation entropy, slow wave activity saturation and alpha-delta amplitude-phase coupling. RESULTS: Volitional responses to verbal command occurred in six out of 90 patients. Three responses occurred immediately following intubation in patients (from Sites 1 and 2) exhibiting an alpha-delta dominant (delta power >20 dB, alpha power >10 dB) EEG pattern. The power-frequency spectra obtained during these responses were similar to those of non-responders (P>0.05) at those sites. A further three responses occurred in (Site 3) patients not exhibiting the classic alpha-delta EEG pattern; these responses occurred later relative to intubation, and in patients had been co-administered ketamine and less volatile anaesthetic compared with Site 1 and 2 patients. None of the derived depth-of-anaesthesia indices could robustly discrimate IFT responders and non-responders. CONCLUSIONS: Connected consciousness can occur in the presence of the frontal alpha-delta EEG pattern during anaesthesia. Frontal EEG parameters do not readily discriminate volitional responsiveness (a marker of connected consciousness) and unresponsiveness during anaesthesia. CLINICAL TRIAL REGISTRATION: NCT02248623.

[Processed EEG for personalized dosing of anesthetics during general anesthesia]. / Das prozessierte EEG zur personalisierten Dosierung von Anästhetika während Allgemeinanästhesie.

Electroencephalogram (EEG)-guided anesthesia is indispensable in modern operating rooms and has become established as the standard form of monitoring. Many anesthesiologists rely on processed EEG indices in the hope of averting anesthesia-related complications, such as intraoperative awareness, postoperative delirium and other cognitive complications in their patients. This educational review aims to provide information on the five most prevalent monitors used to guide depth of sedation during general anesthesia. This article elucidates the principles underpinning the application of these monitors where known, which are generally based on power in various EEG frequency bands and on the burst suppression pattern. Convinced that EEG-guided anesthesia has the potential of benefitting many surgical patients, it is felt that many basic principles and shortcomings of processed EEG indices need to be better understood in the clinical practice. After discussing the different monitors and clinically relevant data from the literature, the article gives a short practical guidance on how to critically interpret processed EEG information and troubleshooting of confounded indices in the context of clinical situations.

Intermittent diaphragmatic hernia of Bochdalek: report of a case and literature review.

Congenital diaphragmatic hernias appearing in late infancy or childhood are entities distinct from the more common newborn disorder. "Delayed" diaphragmatic hernias are associated with prior normal chest roentgenograms. Symptomatic intermittent herniation of abdominal viscera through a congenital posterolateral defect has not been previously reported in 17 cases of late-onset diaphragmatic herniation and may explain the latency period seen in older children.

Sonography in the diagnosis and management of hydrops of the gallbladder in children with mucocutaneous lymph node syndrome.

Acute hydrops of the gallbladder is described in four patients who had mucocutaneous lymph node syndrome. Diagnosis was readily made with gray-scale ultrasound, and the patients were followed with this technique. The gallbladder returned to normal size in all of the patients within 15 days, and none of the patients needed surgery. The role of surgery in acute hydrops of the gallbladder is for the complications of the hydrops and not for distention alone.

Congenital cystic adenomatoid malformation.

Congenital cystic adenomatoid malformation is an uncommon congenital anomaly. We present four additional children with CCAM and review the literature. Two of these children had unusual manifestations of CCAM--one presented with a "cavitary lesion" while the other is suspected of having bilateral disease.

Changing clinical trends in patients with peripheral arterial emboli.

One hundred and twenty-four patients treated by Fogarty balloon catheter embolectomy from 1964 through 1973 were reviewed and compared to an earlier series of 82 patients treated by direct extraction during the interval from 1948 to 1963. In patients undergoing embolectomy, the incidence of rheumatic heart disease (RHD) declined from 55 to 27 percent, and that of arteriosclerotic heart disease (ASHD) rose from 39 to 55 percent. The operative mortality rate of those with RHD was unchanged and that of patients with ASHD declined from 74 to 36 percent. This was attributed, in part, to the lesser degree of operative stress entailed by the Fogarty catheter and the local anesthesia. Limb salvage was 82 percent when ischemic symptoms were less than 24 hours in duration and 66 percent when such symptoms were more than 24 hours in duration. The amputation rate for the entire group was 22 percent. The low 2 year survival of patients with ASHD and of amputees was ascribed to the wide extent of their atherosclerotic cardiovascular disease. This was emphasized by the fact that 44 percent of late deaths were due to myocardial infarction.

Management of mucosal perforation during pyloromyotomy for infantile pyloric stenosis.

Mucosal perforation during Fredet-Ramstedt pyloromyotomy is the cause of unnecessary morbidity and death if unrecognized. Previously, a variety of closure have been advocated. In 1,777 cases there has been 42 (2.3%) intraoperative perforations. One unrecognized perforation led to a postoperative death. Closure of a mucosal tear is accomplished safely by a simplified suture technique without prolonged convalescence or death.

Atresia of the esophagus. New trends in the management of high-risk neonates.

Once the reconstruction of esophageal atresia in infancy was reported, immediate repair became standard practice. High-risk infants carry an operative mortality of 30% to 80%. Staged surgical procedures were introduced to improve survival. "Delayed" reconstruction of esophageal atresia in selected cases has been reported to improve survival and eliminate staged surgical procedures. Between 1982 and 1986, 21 newborns were diagnosed as having esophageal atresia. Eight infants (32%) underwent "immediate" repair. In 13 infants repair was "delayed" for seven to 252 days. Four neonates with "pure" esophageal atresia underwent primary anastomosis, one was awaiting surgery, and another died in the postnatal period. As more high-risk infants survive the perinatal period, surgical reconstruction must be planned to maximize operative survival. The goal of delayed management of esophageal atresia is to restore intrinsic esophageal continuity.

Repair of pectus excavatum deformities in children: a new perspective of treatment using minimal access surgical technique.

HYPOTHESIS: Minimally invasive correction of pectus excavatum (PE) deformities of the anterior chest wall in children is safe and effective. DESIGN: Prospective cohort study. SETTING: Tertiary pediatric referral center. PATIENTS: Between February 1996 and July 2000, 36 patients underwent minimally invasive repair (MIR) of PE deformities, and 6 patients had traditional Ravitch repairs (RR). MAIN OUTCOME MEASURES: Morbidity, operating time, estimated blood loss, days to tolerating a regular diet, and length of hospital stay. RESULTS: Thirty-six children underwent MIR for moderate to severe chest wall deformities, with a mean operative time of 1.6 hours, a mean blood loss of 22 mL, a mean time to tolerating a regular diet of 2.9 days, no intensive care unit admissions, and a mean length of hospital stay of 5.5 days. Six children had RR procedures performed for moderate to severe deformity, with a mean operative time of 5.2 hours, a mean blood loss of 222 mL, a mean time to tolerating a regular diet of 3.3 days, 2 patients admitted to the intensive care unit, and a mean length of hospital stay of 4.5 days. Complications for both procedures consisted mainly of postoperative pneumothorax. CONCLUSIONS: The MIR technique for PE is less invasive, less morbid, and better tolerated than traditional open RR of this common pediatric chest wall deformity. Elective surgical reconstruction can be safely performed in children rather than limiting repair to only symptomatic patients with severe deformities.

Congenital pulmonary lymphangiectasia: a case report of thoracic duct agenesis.

We present a 17-year-old Caucasian male with congenital pulmonary lymphangiectasia and an absent thoracic duct. This patient is unique as he did not present with the disorder until age 9.5 years. Since his initial presentation he has had recurrent chylothoraces and has been treated symptomatically. We discuss the possible implications of his disorder as well as some of the limited treatment that is available.

Early laminar excision: improved control of burn wound sepsis by partial dermatome debridement.

The large mass of devitalized tissue that comprises the burn eschar is gradually becoming recognized as the principal source of complications in the burn patient. Clinical observations suggest that the topical agent silver sulfadiazine does not penetrate the eschar sufficiently to prevent bacterial infection from becoming established in the deeper levels of the wound but does penetrate to a depth of approximately 1.5 mm in bactericidal concentrations. A new technique that takes advantage of this fact, early laminar excision, has been developed at the Children's Hospital of Michigan Burn Center. The eschar is excised layer by layer with the electric dermatome under general anesthesia within the first 72 hr post burn, and the thickness of the devitalized tissue is reduced to a remnant of less than 1 mm. This is less than the depth to which silver sulfadiazine is capable of penetrating in bactericidal concentrations, and greatly enhanced control of burn wound sepsis is achieved. Early laminar excision of the eschar, combined with silver sulfadiazine dressings, aggressive resurfacing of the wound, and increased emphasis on nutrition, is an approach to management of the victims of thermal trauma that should significantly improve survival in patients with burn injuries greater than 60% body surface area.

Testicular epidermoid cysts in prepubertal children: case report and review of the world literature.

Epidermoid cysts of the testes are rare, benign lesions that account for approximately 1% of all testicular tumors. They present most often between the second and fourth decade of life, and have been reported in prepubertal children rarely. The authors report the clinical and sonographic findings in a 4 1/2-year-old child with a testicular epidermoid cyst, and they analyze the 22 prepubertal cases found in the world literature. As described below, the clinical and sonographic features of this tumor are not specific for an epidermoid cyst and do not preclude a teratomatous or malignant neoplasm. This case adds to the varied sonographic appearance of prepubertal testicular epidermoid cysts. The lack of either unique clinical or sonographic features would suggest that extreme caution be used if local excision is considered for a patient with presumed epidermoid cyst of the testicle.

The treatment of retained peripheral foreign bodies in the pediatric airway.

Aspiration of foreign bodies into the pediatric airway is a common surgical emergency condition. Once impacted into the peripheral airway, repeated attempts at removal may push these objects into segmental bronchi, causing endobronchial bleeding, and prolonged anesthesia time. In addition to standard endoscopic techniques, the use of fluoroscopy, endobronchial contrast material, topical vasoactive medications, and diverse retrieval instruments in eight such cases has avoided the need for either bronchotomy or segmental pulmonary resection. By using such supportive intraoperative techniques, the morbidity and mortality from impacted airway foreign bodies can be greatly reduced.

Balloon dilation of esophageal strictures in children.

Esophageal strictures in children may develop as a primary constriction, secondary to a surgically repaired esophageal atresia (with or without tracheoesophageal fistula), as a result of chemical injury after caustic ingestion, or following esophageal surgery. Traditional treatment of esophageal strictures has been limited to dilation (using bougie dilators) with esophagoscopy under general anesthesia. Recent reports have shown success with fluoroscopically guided balloon catheter dilation. Eight children (aged 2 months to 14 years) were treated with balloon catheter dilation for focal strictures of the esophagus. In six of the eight cases, complete resolution of the strictures was achieved after an average of 7.5 dilations (range, 1 to 14). Two of the eight patients moved to another part of the country and did not complete treatment. There has been no morbidity or mortality. In selected centers, balloon catheter dilation under fluoroscopic guidance has become a safe treatment of benign esophageal strictures in children. It should be considered the treatment of choice in the initial management of esophageal narrowing and appears to be safer than the more traditional methods of esophageal dilation.