[Risk Factors for Postoperative Delirium after Cardiac Surgery]. / Risikofaktoren des postoperativen Deliriums in der Herzchirurgie.

Background Delirium is a common psychiatric disorder after cardiac surgery and predisposes patients to increased mortality and morbidity. Its prevention requires knowledge of the risk factors involved. Objective What are preoperative risk factors for postoperative delirium after cardiac surgery? Methods Prospective longitudinal study of 241 elective cardiac surgical patients with preoperative assessment of potential risk factors and delirium assessment twice daily over five postoperative days. Results 13 % of the patients experienced delirium. Reduced cognitive performance (OR: 3.80; 95 % CI: 1.66 - 8.66), higher comorbidity (OR: 1.36; 95 % CI: 1.07 - 1.7) and higher age (OR: 1.08; 95 % CI: 1.02 - 1.13) increased the risk of delirium. Conclusion Delirium after cardiac surgery is common. It occurs in particular in patients with low cognitive performance, higher comorbidity and higher age.

Functional residual capacity-guided alveolar recruitment strategy after endotracheal suctioning in cardiac surgery patients.

OBJECTIVE: To determine whether the results of functional residual capacity measurements after endotracheal suctioning could guide the decision to perform an alveolar recruitment maneuver and thus improve lung function. DESIGN: Prospective, randomized, controlled interventional study. SETTING: Intensive care unit of a university hospital. PATIENTS: Fifty-nine mechanically ventilated patients within 2 hrs after elective cardiac surgery without preexisting lung diseases. INTERVENTIONS: Patients received a standard suctioning procedure with disconnection of the ventilator (20 secs, 14 F catheter, 200 cm H2O negative pressure). Prospectively, patients were stratified into two groups by the postsuctioning functional residual capacity value (group A: functional residual capacity >94% of baseline; group B: functional residual capacity <94% of baseline). Both groups were randomized into either a recruitment maneuver (RM) group (positive end-expiratory pressure 15 cm H2O, peak inspiratory pressure 35-40 cm H2O for 30 secs, group RM) or a non-RM group, in which ventilation was resumed without an RM (group NRM), resulting in four groups. MEASUREMENTS AND MAIN RESULTS: Functional residual capacity and arterial blood gases were recorded for up to 1 hr. In addition, distribution of ventilation was measured by means of electrical impedance tomography. The RM had an impact on distribution of ventilation, functional residual capacity, and oxygenation in patients with a decrease of functional residual capacity after suctioning. In contrast, the RM showed no impact on these parameters in patients with no decrease of functional residual capacity after suctioning. CONCLUSIONS: By measurements of functional residual capacity after endotracheal suctioning, patients profiting from a consecutive recruitment maneuver could be identified. Guiding the recruitment strategy on changes of functional residual capacity may improve patient care.

Relationship between functional residual capacity, respiratory compliance, and oxygenation in patients ventilated after cardiac surgery.

BACKGROUND: Measurement of functional residual capacity (FRC) is now possible at bedside, during mechanical ventilation. OBJECTIVES: To determine the relationship of measured absolute and relative predicted FRC values to oxygenation and respiratory-system compliance, and to identify variables that influence FRC in ventilated patients after cardiac surgery. METHODS: We retrospectively analyzed data from 99 patients ventilated after cardiac surgery. Each patient underwent an alveolar recruitment maneuver and was then ventilated with a positive end-expiratory pressure of 10 cm H2O and a tidal volume of 6-8 mL/kg predicted body weight. We measured quasi-static 2-point compliance of the respiratory system, FRC (with the oxygen-wash-out method), PaO2, and fraction of inspired oxygen (F(I)O2). We indexed the FRC values to predicted FRC reference values from sitting and supine healthy volunteers. RESULTS: Correlation analyses revealed no meaningful association between FRC and PaO2/F(I)O2 (r2 0.20, P < .001). There was a moderate association between absolute FRC and respiratory-system compliance (r2 0.50, P < .001). Indexing the absolute measured FRC values to the predicted FRC values did not improve the correlation. We conducted multiple linear regression analyses of height, weight, age, sex, presence of mild chronic obstructive pulmonary disease, minute volume, and peak inspiratory pressure during ventilation, and revealed weight, minute volume, and peak inspiratory pressure (r2 = 0.65) as independent covariates of FRC. CONCLUSIONS: Indexing the measured FRC values to the predicted supine and sitting FRC values does not improve the association between PaO2/F(I)O2 and respiratory-system compliance. In mechanically ventilated patients after cardiac surgery, FRC is influenced more by the ventilator settings than by physiologic variables (as in spontaneously breathing persons).

Changes in functional residual capacity during weaning from mechanical ventilation: a pilot study.

BACKGROUND: Reduction of high positive end-expiratory pressure levels and pressure support ventilation (PSV) are frequently used before tracheal extubation in critically ill patients, but the impact of PSV on functional residual capacity (FRC) is unknown. In this study, we sought to detect the changes of FRC and pulmonary function during a weaning protocol in patients ventilated after cardiac surgery. METHODS: The LUFU system (Dräger Medical, Lübeck, Germany) estimates FRC by oxygen washout, a variant of multiple breath nitrogen washout, using a sidestream O(2) analyzer. Postoperative cardiac surgery patients were initially ventilated using biphasic positive airway pressure ventilation (BiPAP) with a positive end-expiratory pressure of 10 mbar. The upper pressure limit was adjusted to deliver a tidal volume of 6-8 mL/kg (BIPAP 10). After 30 min, the upper and lower pressure limits were both reduced by 3 mbar (BIPAP 7). When spontaneous breathing efforts were detected, ventilation mode was switched to continuous positive airway pressure (CPAP) with PSV using the former lower pressure limit as the CPAP level and the corresponding pressure support of the former BIPAP adjustment (CPAP 7_1). Measurements were repeated after 30 min (CPAP 7_2). RESULTS: Ten patients were studied. FRC decreased (BIPAP 10: 3.6 [1.0] L; BIPAP 7: 3.1 [0.9] L; CPAP 7_1: 2.9 [0.9] L; CPAP 7_2: 2.7 [0.6] L [Mean (SD)]; MANOVA: P = 0.017), as did PF ratio (BIPAP 10: 420 [114] mm Hg; BIPAP 7: 405 [110] mm Hg; CPAP 7_1: 353 [70] mm Hg; CPAP 7_2: 340 [70] mm Hg [Mean (SD)]; MANOVA: P = 0.045). PaCO(2) did not change significantly over time (P = 0.221). CONCLUSION: Decreasing FRC during the weaning process after cardiac surgery may, at least in part, be explained by alveolar derecruitment. Whether this variable could help guide a weaning protocol has to be studied further.

Increased mortality in long-term intensive care patients with active cytomegalovirus infection.

OBJECTIVE: To determine the prevalence and impact on patient outcome of active human cytomegalovirus infections in patients with prolonged treatment in an intensive care unit. DESIGN: Retrospective analysis of stored plasma samples. SETTING: Anesthesiological intensive care unit of a university hospital. PATIENTS: All 138 patients treated for at least 14 days (of a total of 4940 patients admitted during the study period). Immunocompromised patients and patients with inconclusive results for cytomegalovirus DNA were excluded. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Stored plasma samples of patients with prolonged intensive care unit stay were tested for cytomegalovirus DNA. Sixty-four of 255 evaluable samples from 99 immunocompetent patients tested cytomegalovirus DNA-positive with a mean DNA concentration of 8,600 genome equivalents per milliliter. Active cytomegalovirus infection was diagnosed by reproducibly positive results in 35 patients (35%). Only one case had been diagnosed clinically. Patients with and without active cytomegalovirus infection were not significantly different in parameters, such as age, sex, admission category, source of admission, or comorbidities. Even review of specific surgical procedures or the use of a heart-lung-machine showed no significant differences between the groups. The mortality rate in patients with cytomegalovirus infection was significantly increased (28.6% vs. 10.9%, p = 0.048), and surviving patients had a longer intensive care unit stay (32.6 vs. 22.1 days, p <0.001). CONCLUSIONS: Active cytomegalovirus infection is a frequent but seldom diagnosed finding in surgical patients with prolonged intensive care unit stay, which is associated with increased mortality and prolonged intensive care unit stay of surviving patients.

Functional residual capacity changes after different endotracheal suctioning methods.

BACKGROUND: Our primary objective was to investigate the effects of three different endotracheal suctioning procedures on functional residual capacity (FRC). METHODS: Using a crossover design, postoperative cardiac surgery patients (n = 20) received three different suctioning methods in randomized order: closed suctioning during pressure-controlled ventilation, closed suctioning during volume-controlled ventilation, and open suctioning. FRC was measured before and 20 min after the intervention. RESULTS AND CONCLUSIONS: FRC is reduced in postcardiac surgery patients after suctioning, regardless of which method is used. Certain patients may have very pronounced changes of FRC. Routine FRC measurements could complement respiratory monitoring to optimize respiratory therapy.

The impact of different step changes of inspiratory fraction of oxygen on functional residual capacity measurements using the oxygen washout technique in ventilated patients.

BACKGROUND: Functional residual capacity (FRC) measurements may help to guide respiratory therapy. Using the oxygen washout technique, FRC can be assessed at bedside during spontaneous breathing. High repeatability, crucial for monitoring, has not been shown in ventilated patients. A large step change of inspiratory fraction of oxygen (FiO(2)) (DeltaFiO(2)) may impede the clinical use in patients ventilated with high FiO(2). We investigated the repeatability of FRC measurements and the impact of different DeltaFiO(2) on this repeatability. METHODS: The LUFU system (Draeger Medical, Luebeck, Germany) estimates FRC by oxygen washout, a variant of multiple-breath-nitrogen-washout during a fast DeltaFiO(2). In 20 postoperative cardiac surgery patients, FRC was measured in duplicate using DeltaFiO(2) of 0.1, 0.2, and 0.6. RESULTS: There were no differences between repeated measurements of FRC, neither using a DeltaFiO(2) of 0.1, 0.2 nor 0.6(Delta0.1: 2.62 L +/- 0.58, 2.62 L +/- 0.59, P = 0.995; Delta0.2: 2.70 L +/- 0.59, 2.66 L +/- 0.56, P = 0.258; Delta0.6: 2.61 L +/- 0.58, 2.59 L +/- 0.58, P = 0,639). Coefficients of variation were 6.6%, 5.6%, and 6.6%, respectively. CONCLUSIONS: FRC can be measured in ventilated patients using the oxygen washout technique with a clinically acceptable repeatability. Repeatability is not significantly influenced whether using a DeltaFiO(2) of 0.1, 0.2, or 0.6.

Acetylcholinesterase and butyrylcholinesterase in cardiosurgical patients with postoperative delirium.

BACKGROUND: Patients in intensive care units (ICU) are often diagnosed with postoperative delirium; the duration of which has a relevant negative impact on various clinical outcomes. Recent research found a potentially important role of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) in delirium of critically ill patients on non-surgical ICU or in non-cardiac-surgery patients. We tested the hypothesis that AChE and BChE have an impact on patients after cardiac surgery with postoperative delirium. METHODS: After obtaining approval from the local ethics committee, this mechanistic study gathered data of all 217 patients included in a randomized controlled trial testing non-pharmacological modifications of care in the cardiac surgical ICU to reduce delirium. Delirium was assessed with the Confusion Assessment Method for the Intensive Care Unit (CAM-ICU) and the Nursing Delirium Screening Scale (Nu-DESC) twice a day for the first 3 days after surgery. Further outcome variables were somatic laboratory parameters and variables regarding surgery, anesthesia, and postsurgical recovery. 10 µl venous or arterial blood was drawn and AChE and BChE were determined with ChE check mobile from Securetec. RESULTS: Of 217 patients, 60 (27.6%) developed postsurgical delirium (POD). Patients with POD were older (p = 0.005), had anemia (p = 0.01), and worse kidney function (p = 0.006). Furthermore, these patients had lower intraoperative cerebral saturation (NIRS) (p < 0.001) and higher intraoperative need of catecholamines (p = 0.03). Delirious patients showed more inflammatory response (p < 0.001). AChE and BChE values were mainly inside the norm. Patients with values outside the norm did not have POD more often than others. Regarding AChE and BChE patients did not differ in having delirium or not (p > 0.10). CONCLUSIONS: Postoperative measurement of AChE and BChE did not discern between patients with and without POD. The effect of the cardiac surgical procedure on AChE and BChE remains unclear. Further studies with patients in cardiac surgery are needed to evaluate a possible combination of delirium and the cholinergic transmitter system. There might be possible interactions with AChE/BChE and blood products and the use of cardiopulmonary bypass, which should be investigated more intensively. TRIAL REGISTRATION: German Clinical Trials Register, DRKS00006217.

[Indication for antimycotic therapy for tracheobronchial candidosis under artificial ventilation]. / Indikationsstellung zur antimykotischen Therapie bei der tracheobronchialen Candidose unter Beatmung.

Tracheobronchial candidosis is an impetuous complication in intensive care medicine. This article presents a concept to compare diagnostic procedure, Candida species and resistant species of different intensive care units with each other. This concept should encourage bench marking between similar intensive care units. The report and retrospective analysis of the intensive care course offer the opportunity to reflect own decisions and to adjust them to the current therapy strategies. Both procedures should improve the antimycotic therapy for intensive care units and should avoid the occurrence of resistant species. Candida species are often detected in the respiratory system of ventilated patients in intensive care, but this alone is no indication for antimycotic therapy. A strict retention is recommended, but this retention is diminished by an unclear infection, critical situation of the patient in the case of multiple organ failure, additional infection and long term ventilation. A therapy strategy for individual situations should be established and a close diagnostic procedure should be performed. A positive blood culture or detection of Candida species in two or more diagnostic materials indicate an early antimycotic therapy.

Bronchial stenting and high-frequency percussive ventilation treatment of descending aortic aneurysm-induced atelectasis of the left lung.

IMPLICATIONS: This case report shows that atelectasis of the left lung-induced by extrinsic compression of the left main bronchus by an aortic aneurysm and persisting despite aggressive conservative treatment-may be effectively treated by bronchial stenting and high-frequency percussive ventilation.