A ventilation strategy during general anaesthesia to reduce postoperative atelectasis

Background. Atelectasis is common during and after general anaesthesia. We hypothesized that a ventilation strategy, without recruitment manoeuvres, using a combination of continuous positive airway pressure (CPAP) or positive end-expiratory pressure (PEEP) and a reduced end-expiratory oxygen fraction (F_ETO₂) before ending mask ventilation with CPAP after extubation would reduce the area of postoperative atelectasis.

Methods. Thirty patients were randomized into three groups. During induction and emergence, inspiratory oxygen fractions (F_IO₂) were 1.0 in the control group and 1.0 or 0.8 in the intervention groups. No CPAP/PEEP was used in the control group, whereas CPAP/PEEP of 6 cmH₂O was used in the intervention groups. After extubation, F_IO₂ was set to 0.30 in the intervention groups and CPAP was applied, aiming at F_ETO₂ < 0.30. Atelectasis was studied by computed tomography 25 min postoperatively.

Results. The median area of atelectasis was 5.2 cm² (range 1.6–12.2 cm²) and 8.5 cm² (3–23.1 cm²) in the groups given F_IO₂ 1.0 with or without CPAP/PEEP, respectively. After correction for body mass index the difference between medians (2.9 cm²) was statistically significant (confidence interval 0.2–7.6 cm², p = 0.04). In the group given F_IO₂ 0.8, in which seven patients were ex- or current smokers, the median area of atelectasis was 8.2 cm² (1.8–14.7 cm²).

Conclusion. Compared with conventional ventilation, after correction for obesity, this ventilation strategy reduced the area of postoperative atelectasis in one of the intervention groups but not in the other group, which included a higher proportion of smokers.     

Single-Molecule hsTnI and Short-Term Risk in Stable Patients With Chest Pain

Background

Evaluation of stable symptomatic outpatients with suspected coronary artery disease (CAD) may be challenging because they have a wide range of cardiovascular risk. The role of troponin testing to assist clinical decision making in this setting is unexplored.

Validation of diffuse correlation spectroscopy against 15O-water PET for regional cerebral blood flow measurement in neonatal piglets

Diffuse correlation spectroscopy (DCS) can non-invasively and continuously asses regional cerebral blood flow (rCBF) at the cot-side by measuring a blood flow index (BFI) in non-traditional units of cm²/s. We have validated DCS against positron emission tomography using ¹⁵O-labeled water (¹⁵O-water PET) in a piglet model allowing us to derive a conversion formula for BFI to rCBF in conventional units (ml/100g/min). Neonatal piglets were continuously monitored by the BabyLux device integrating DCS and time resolved near infrared spectroscopy (TRS) while acquiring ¹⁵O-water PET scans at baseline, after injection of acetazolamide and during induced hypoxic episodes. BFI by DCS was highly correlated with rCBF (R = 0.94, p < 0.001) by PET. A scaling factor of 0.89 (limits of agreement for individual measurement: 0.56, 1.39)×10⁹× (ml/100g/min)/(cm²/s) was used to derive baseline rCBF from baseline BFI measurements of another group of piglets and of healthy newborn infants showing an agreement with expected values. These results pave the way towards non-invasive, cot-side absolute CBF measurements by DCS on neonates.     

Multidetector-row computed tomography and magnetic resonance imaging of atherosclerotic lesions in human ex vivo coronary arteries

In the present study, we tested the ability of multidetector-row computed tomography (MDCT) and magnetic resonance imaging (MRI) to identify and retrospectively characterize atherosclerotic lesions in human ex vivo coronary arteries. Thirteen ex vivo hearts were studied with MDCT and MRI. MDCT-images were obtained with an isotropic voxel size of 0.6mm(3). MR images were obtained with an in-plane resolution of 195 microm and 3mm slice thickness. All images were matched with histopathology sections. For both modalities, the sensitivity for the detection of any atherosclerotic lesion was evaluated, and a retrospective analysis of plaque morphology according to criteria defined by the American Heart Association (AHA) was performed. At histopathology, 28 atherosclerotic lesions were found. 21 and 23 of these lesions were identified by MDCT and MRI, respectively. Both modalities detected a small number of false-positive lesions. After retrospective matching with histopathology, MDCT as well as MRI were able to differentiate typical morpholocigal features for fatty, fibrous or calcified plaque components. Using the information presented in this study, in vivo coronary artery wall imaging using MDCT as well as MRI could be facilitated and supported for future investigations on this subject.     

Detection of Lymphatic Micrometastases in Patients With Stages I and II Colorectal Cancer: Impact on Five-Year Survival

PURPOSE: Despite having removed the whole macroscopic disease (curative intent surgery), one of five patients with Stages I and II colorectal cancer will develop recurrence. Lymphatic micrometastases detected by immunohistochemistry could be one of explanation for recurrence and cancer-related death in patients without lymph node involvement at light microscopy. However, the biologic importance of micrometastases remains unclear. This study was designed to determine the impact of micrometastases in five-year survival in patients with Stages I and II colorectal cancer.METHODS: This retrospective study included patients operated on between May 1989 and January 1999 for colorectal cancer without histopathologic lymph node involvement. Patients who received any adjuvant therapy were excluded. Immunohistochemical staining of the lymph nodes was performed with antipancytokeratin antibodies. Follow-up data were obtained from the clinical database and death certificates. Survival was estimated by the Kaplan-Meier method and compared by the log-rank test.RESULTS: Micrometastases were observed in 26 of 90 patients (28.9 percent). The mean follow-up time was 90.7 (range, 11–160) months. Seventeen cancer-related deaths occurred during follow-up (18.9 percent), 6 of them in patients with micrometastases (23.1 percent) and 11 in patients without micrometastases (17.2 percent; P = 0.559). Cancer-specific five-year survival was 87 percent in the whole group and 81 percent in patients positive for micrometastases vs. 90 percent in negative patients (P = 0.489).CONCLUSIONS: The presence of micrometastases in patients with Stages I and II colorectal cancer seems not to have any impact on cancer-specific survival.Supported by the Apertus Research Program (Andromaco Pharmaceutical Company) and by The National Public Grant (FONDECYT #1000556).     

Antwort auf den Leserbrief von Valhaus et al. Zu unserer Kasuistik „Kardiogener Schock 4 Stunden nach akut-PTCA bei Hinterwandinfarkt“

Ohne Zusammenfassung