Beate Sedemund-Adib

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.

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.

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 (Fio2) (&Dgr;Fio2) may impede the clinical use in patients ventilated with high Fio2. We investigated the repeatability of FRC measurements and the impact of different &Dgr;Fio2 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 &Dgr;Fio2. In 20 postoperative cardiac surgery patients, FRC was measured in duplicate using &Dgr;Fio2 of 0.1, 0.2, and 0.6. RESULTS:There were no differences between repeated measurements of FRC, neither using a &Dgr;Fio2 of 0.1, 0.2 nor 0.6(&Dgr;0.1: 2.62 L ± 0.58, 2.62 L ± 0.59, P = 0.995; &Dgr;0.2: 2.70 L ± 0.59, 2.66 L ± 0.56, P = 0.258; &Dgr;0.6: 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 &Dgr;Fio2 of 0.1, 0.2, or 0.6.

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 O2 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). Paco2 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.

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.

Correlation of Noninvasive Cerebral Oxygenation with Mixed Venous Oxygen Saturation in Patients undergoing ECMO-Therapy - A Pilot Study

Approximately 1% of patients require temporary circulatory support due to cardiogenic shock following cardiac surgery. These patients are at risk of a mismatch between oxygen delivery and demand and carry a substantial mortality and morbidity risk. Mixed venous oxygen saturation (SvO2) is the still the “gold standard” for the determination of the ratio between systemic oxygen delivery and consumption (DO2/VO2 ratio) in cardiac surgery patients. However, in patients undergoing prolonged extracorporeal membrane oxygenation (ECMO), a noninvasive and continuous technique for early detection of a systemic DO2/VO2 ratio would be desirable. One such technique is thought to be cerebral near-infrared spectroscopy (cNIRS) determining cerebral oxygen saturation (rSO2). The present analysis aims to compare rSO2 and SvO2 levels in adult patients undergoing ECMO therapy for postoperative cardiogenic shock. Data were collected hourly for the first 24 hours post operatively. Each patient was equipped with a pulmonary artery catheter (PAC) for continuous determination of SvO2 connected to a Vigilance II® - monitor (Edwards Lifesciences, Irvine, USA) and an INVOS 5100 monitoring system (Somanetics, Troy, USA) to determine rSO2. Data were analyzed by parametric testing and Bland-Altman analysis. Up to now 5 patients could be included in this ongoing prospective, observational study. SvO2 and rSO2 did not change significantly throughout the observation period. The correlation coefficient between both methods was 0.96 (95% CI: 0.98 to 0.99; p < 0.0001). Bland-Altman analysis showed a mean difference (bias) of -0.16% and limits of agreement of 0.06% to - 0.39. These data suggest for the first time that rSO2 highly correlates with SvO2 in patients undergoing ECMO therapy and therefore determining rSO2 may be a noninvasive alternative to monitor the DO2/VO2 ratio during this condition.