Electrical impedance tomography may optimize ventilation in a postpartum woman with respiratory failure.

Amniotic fluid embolism is a rare peripartum complication with the sudden onset of haemodynamic instability, respiratory failure and coagulopathy during labour or soon after delivery. A 31-year-old woman with amniotic fluid embolism was treated with vasopressors, inotropes, intravenous fluid, tranexamic acid and ventilatory support. Assessment of respiratory impairment was made using conventional chest X-ray, computed tomography and electrical impedance tomography. The potential for electrical impedance tomography to improve monitoring and guide respiratory therapy is explored.

[Outbreak of Burkholderia cepacia complex caused by contaminated alcohol-free mouthwash]. / Ausbruch mit Burkholderia-cepacia-Komplex durch kontaminierte Mundspüllösung.

BACKGROUND: A total of three intensive care units (ICU) at a German university hospital were involved in an outbreak of Burkholderia cepacia complex (Bcc). METHODS: Patients with microbiological detection of Bcc were evaluated. Products used for mouth hygiene were microbiologically tested. The clonal identity of Bcc was proven by pulse-field gel electrophoresis (PFGE). RESULTS: On 3 ICUs 12 cases were identified whereby the first detection of Bcc was in respiratory specimens of 11 patients and 1 in a wound swab from the oral cavity. Of these patients six developed ventilator-associated pneumonia (VAP). Investigations revealed that five different batches of an alcohol-free mouthwash containing hexetidine were highly contaminated. Isolates of Bcc from patients and mouthwashes were genetically indistinguishable. A recall of the product was initiated. After elimination of the product from the ICUs no more cases were identified. CONCLUSIONS: The source of the outbreak was an intrinsically contaminated alcohol-free mouthwash. Detection of Bcc in specimens from ICU patients should lead to further investigations. Antiseptic oral care products are recommended for reducing the risk of VAP but they may be microbiologically contaminated and, in consequence, increase the risk. The safety of patient care products should be increased by stricter regulations.

Relationship between mixed venous oxygen saturation and regional cerebral oxygenation in awake, spontaneously breathing cardiac surgery patients.

BACKGROUND: In search of a non-invasive method for estimation of the oxygen balance this prospective study evaluates the relationship between regional cerebral oxygenation (rScO2) and mixed venous oxygen saturation in awake, spontaneously breathing patients after cardiac surgery. METHODS: After approval by the local ethical committee and written informed consent, 26 consecutive patients after cardiac surgery with cardiopulmonary bypass were enrolled. On intensive care unit (ICU), several hours after extubation, patients were connected to the INVOS 5100 cerebral monitor. Blood samples for determination of mixed venous oxygen saturation (SvO2) and central venous oxygen saturation (ScvO2) were drawn successively and rScO2 was documented. Patients were studied twice, breathing room air for the first measurement cycle, and breathing 4L/min supplemental oxygen by face mask, achieving a transcutaneous oxygen saturation above 98%, for a second measurement. RESULTS: Hemodynamic variables, hemoglobin and arterial carbon dioxide tension (PaCO2) remained stable between the two measurement cycles. Without oxygen, SvO2 and rScO2 showed a bias of -2.0%, limits of agreement (LOA) of -15.0 to 10.9% and a percentage error (PE) of 20.3%. SvO2 and ScvO2 showed a bias of -3.9%, LOA of -13.9 to 6.2% and PE 15.7%. With oxygen, the bias between SvO2 and rScO2 was -2.5%, LOA -14.2 to 9.2%, PE 17.2%. Between SvO2 and ScvO2 the bias was -4.1%, LOA -10.2 to 2.1%, PE 9.0%. CONCLUSION: The rScO2 measured by near infrared spectroscopy was sufficiently representing mixed venous oxygen saturation in awake, hemodynamically stable, spontaneously breathing patients after cardiac surgery. The agreement was comparable to the agreement between SvO2 and ScvO2 with smaller differences in the lower ranges of SvO2.

Cognitive function after sevoflurane- vs propofol-based anaesthesia for on-pump cardiac surgery: a randomized controlled trial.

BACKGROUND: Cognitive dysfunction is a frequent complication after cardiac surgery and has been found to be associated with decreases in cerebral oxygen saturation measured with near-infrared spectroscopy. Sevoflurane has neuroprotective properties in vitro and in animal models. This study was designed to determine cognitive and clinical outcomes after sevoflurane- compared with propofol-based anaesthesia for on-pump cardiac surgery and the impact of decreases in under different anaesthesia regimens. METHODS: One hundred and twenty-eight patients were randomly assigned to either i.v. anaesthesia with propofol- (PROP) or sevoflurane-based anaesthesia (SEVO). An intraoperative was defined as desaturation. The Abbreviated Mental Test, Stroop Test, Trail-Making Test, Word Lists, and mood-assessment tests were performed before, 2, 4, and 6 days after cardiac surgery. Markers of general outcome were obtained. RESULTS: The analysis groups had differences in baseline cognitive performance. Analysis of variance for repeated measures (incorporating covariance of baseline scores) showed that in three of four cognitive tests, patients with cerebral desaturation showed worse results than patients without desaturation. Patients assigned to sevoflurane-based anaesthesia showed better results in all cognitive tests than patients after propofol. Interactions between the anaesthetic regimen and desaturation were found in all four cognitive tests. There were no differences in markers of organ dysfunction or general clinical outcome. CONCLUSIONS: Patients with impaired cognitive performance before operation may be at particular risk for intraoperative cerebral insult. A sevoflurane-based anaesthesia was associated with better short-term postoperative cognitive performance than propofol.

Lack of agreement between pulmonary arterial thermodilution cardiac output and the pressure recording analytical method in postoperative cardiac surgery patients.

BACKGROUND: Pulse-contour analysis method (PCM) cardiac output (CO) monitors are increasingly used for CO monitoring during anaesthesia and in the critically ill. Very recently, several systems have been introduced that do not need calibration; among them the pressure recording analytical method (PRAM). Sparse data comparing the accuracy of the PRAM-CO with conventional thermodilution CO (ThD-CO) in cardiac surgery patients are available. METHODS: In this prospective comparison study, paired CO measurements with a pulmonary artery catheter and a PRAM monitoring set were obtained 20-30 min apart (t1, t2) in 23 extubated patients on the first postoperative day after cardiac surgery. Data were analysed by the Bland-Altman method. RESULTS: A total of 46 paired CO measurements (23 for each interval) were collected. The Bland-Altman analysis showed a mean difference (bias) of 0.0 litre min(-1) and limits of agreement (1.96 sd) of 4.53 to -4.54 litre min(-1) [upper 95% confidence interval (CI), 3.26-5.80; lower 95% CI, -5.8 to -3.27]. The percentage error (1.96 sd/mean of the reference method) was 87%. CONCLUSIONS: These results question the reliability of the PRAM technology for the determination of CO in postoperative cardiac surgery patients.

[Confusion Assessment Method for the Intensive Care Unit (CAM-ICU): diagnosis of postoperative delirium in cardiac surgery]. / Confusion Assessment Method for the Intensive Care Unit (CAM-ICU): diagnostik des postoperativen delirs bei kardiochirurgischen Patienten.

OBJECTIVE: Since 2001 the Confusion Assessment Method for the Intensive Care Unit (CAM-ICU), a method for the diagnosis of delirium, has been available for the Anglo American area which can also be applied to mechanically ventilated patients. This study was conducted to answer the following questions: 1. Can a German version of the CAM-ICU be applied to patients after cardiac surgery? 2. What is the prevalence rate of postoperative delirium after cardiac surgery diagnosed by the CAM-ICU? 3. Do patients with and without the diagnosis delirium differ in the clinical variables usually associated with this disorder in cardiac surgery? METHODS: A total of 194 patients undergoing cardiac surgery served as the analysis sample (85.5% of the total group). The CAM-ICU was carried out every day for 5 days after the operation. Sociodemographic and clinical variables were collected to examine the validity of CAM-ICU. Postoperative complaints were assessed by the Anaesthesiological Questionnaire for Patients (ANP). RESULTS: Postoperatively, the CAM-ICU could be applied to almost all patients without any problems. The prevalence rate of delirium was 28.4% and 85.5% of the delirium diagnosed was a hypoactive subtype when diagnosed for the first time. Patients with delirium diagnosed by CAM-ICU were older (p<0.001), had a lower educational level (p<0.05), longer anaesthesia time and operation time (p<0.05), a longer postoperative ICU stay (p<0.001), were mechanically ventilated for a longer time postoperatively (p<0.001), more often reintubated (p<0.01) and had higher leucocytes postoperatively (p<0.10). More patients with delirium had the lowest postoperatively measured oxygen saturation below 95% (p<0.01). CONCLUSION: The CAM-ICU is an economic method for the assessment of delirium which can easily be learned. It can be applied to patients after cardiac surgery without any problems.

[Diagnosis, procedures and conservative therapy of a bronchial rupture after intubation with double-lumen tube]. / Diagnostik, Procedere und konservative Therapie einer Bronchialruptur nach Doppellumentubusintubation.

Bronchial rupture is a rare but severe complication of intubation with a double-lumen tube. Cardinal symptoms are mediastinal and subcutaneous emphysema as well as pneumothorax. Larger injuries result in an air leak and the endtidal carbon dioxide decreases. The gas exchange may worsen drastically when mucosal prolapse or bronchial haemorrhagia lead to bronchial occlusion. Mediastinitis or sepsis can be the sequel of the opened mediastinum. If bronchial injury is suspected probably fibreoptic bronchoscopy is indicated. We report on a case of bronchial rupture due to overinflation of the endobronchial cuff or movement of the inflated cuff when repositioning the patient. The conservative therapy was successful in spite of the fact that surgical intervention is recommended in the literature following bronchial rupture. To avoid tracheobronchial injuries an adequate tubus size must be selected. The more flexible polyvinylchloride (PVC) tubes without a carinal hook should be preferred to the Carlens tube. An atraumatic intubation is promoted by leaving the stylet inside after the tip of the tube has passed the vocal cords. To identify the minimum occlusive pressure of the endobronchial cuff for lung isolation different methods are described and should be used. The cuff has to be deflated when the patient is repositioned and when one-lung-ventilation is not required. Tumours of the tracheobronchial tree and weakness of the bronchial wall caused by steroid hormone therapy or COPD may increase the risk of tracheobronchial laceration.

Effects of propofol vs isoflurane on respiratory gas exchange during laparoscopic cholecystectomy.

BACKGROUND: Respiratory function and pulmonary gas exchange are affected in laparoscopic procedures where a pneumoperitoneum is introduced using CO2. Previous studies have shown differing results concerning pulmonary gas exchange during laparoscopic procedures: Whereas in patients undergoing isoflurane anaesthesia decreases in PaO2 are demonstrated, this factor remains unchanged in patients undergoing propofol anaesthesia. In the present study, the effects of propofol on pulmonary gas exchange were compared with those of isoflurane in patients undergoing elective laparoscopic cholecystectomy in a prospective randomised manner. METHODS: Twenty ASA patients with physical status I and II were divided randomly between isoflurane (IG) and propofol groups (PG). After induction of anaesthesia patients were moderately hyperventilated. Respirator settings remained unchanged during pneumoperitoneum (PP) until 10 min after deflation of the peritoneal cavity. Blood gas analyses were performed at 5 time points: 15 min after induction of anaesthesia (giving pre-PP values), immediately before carbon dioxide insufflation (0 min PP), after both 30 and 60 min of PP and 10 min post PP. Inspiration plateau pressure (Pplat), compliance of the respiratory system, and both ins- and expiratory gas concentrations were continuously recorded by an Ultima V monitor (Datex Corp., Helsinki, Finland). The difference between arterial and end-tidal CO2 partial pressure (P(a-et)CO2) was calculated so as to allow assessment of physiological dead space by the modified Bohr equation. RESULTS: Pulmonary gas exchange differed significantly after 30 min of PP between the IG and the PG. At this time, PaO2 was 19.5 +/- 2.9 kPa (mean +/- SD) in the IG and 23.1 +/- 1.8 kPa in the PG (P < 0.01), whereas PaCO2 was 5.5 +/- 0.37 kPa in the IG and 4.9 +/- 0.27 kPa in the PG (P < 0.01). These discrepancies remained until after carbon dioxide desufflation. At 10 min post PP, PaO2 was 18.3 +/- 2.6 kPa in the isoflurane group and 21.9 +/- 2.2 kPa in the propofol group (P < 0.01), whereas PaCO2 was 5.4 +/- 0.46 kPa in the IG and 4.8 +/- 0.22 kPa in the PG (P < 0.01). During carbon dioxide insufflation the P(a-et)CO2 increased significantly in the IG from 0.47 +/- 0.13 kPa to 0.76 +/- 0.37 kPa (P < 0.05), while the values in the PG remained constant. CONCLUSION: This study demonstrates that pulmonary gas exchange in patients with laparoscopic cholecystectomy is affected by the choice of anaesthetic procedure. During and after laparoscopic cholecystectomy using isoflurane as the anaesthetic, the PaCO2 is significantly higher and the PaO2 significantly lower than they are with propofol.