Evaluation of hyperoxia-induced hypercapnia in obese patients after cardiac surgery: a randomized crossover comparison of conservative and liberal oxygen administration.

PURPOSE: Recent studies on patients with stable obesity-hypoventilation syndrome have raised concerns about hyperoxia-induced hypercapnia in this population. This study aimed to evaluate whether a higher oxygen saturation target would increase arterial partial pressure of carbon dioxide (PaCO2) in obese patients after coronary artery bypass grafting surgery (CABG). METHODS: Obese patients having CABG were recruited. With a randomized crossover design, we compared two oxygenation strategies for 30 min each, immediately after extubation: a peripheral oxygen saturation (SpO2) target of ≥ 95% achieved with manual oxygen titration (liberal) and a SpO2 target of 90% achieved with FreeO2, an automated oxygen titration device (conservative). The main outcome was end-of-period arterial PaCO2. RESULTS: Thirty patients were included. Mean (standard deviation [SD]) body mass index (BMI) was 34 (3) kg·m-2 and mean (SD) baseline partial pressure of carbon dioxide (PCO2) was 40.7 (3.1) mmHg. Mean (SD) end-of-period PaCO2 was 42.0 (5.4) mmHg in the conservative period, compared with 42.6 (4.6) mmHg in the liberal period [mean difference - 0.6 (95% confidence interval - 2.2 to 0.9) mmHg; P = 0.4]. Adjusted analysis for age, BMI, narcotics, and preoperative PaCO2 did not substantively change the results. Fourteen patients were retainers, showing an elevation in mean (SD) PaCO2 in the liberal period of 3.3 (4.1) mmHg. Eleven patients had the opposite response, with a mean (SD) end-of-period PaCO2 decrease of 1.8 (2.2) mmHg in the liberal period. Five patients had a neutral response. CONCLUSION: This study did not show a clinically important increase in PaCO2 associated with higher SpO2 values in this specific population of obese patients after CABG. Partial pressure of carbon dioxide increased with liberal oxygen administration in almost half of the patients, but no predictive factor was identified. TRIAL REGISTRATION: www.clinicaltrials.gov (NCT02917668); registered 25 September, 2016.

Metastatic pattern of invasive lobular carcinoma of the breast-Emphasis on gastric metastases.

BACKGROUND AND OBJECTIVES: Breast invasive ductal carcinoma (IDC) and invasive lobular carcinoma (ILC) have different metastatic patterns, but the exact pattern of metastases from ILC is poorly known. This study aimed to determine the frequency of ILC metastases in atypical locations, with an emphasis on gastric metastases. METHODS: Patients with ILC treated at the Saint-Sacrement Hospital (Quebec City, Canada) and the Maisonneuve-Rosemont Hospital (Montreal, Canada) between January 2003 and December 2009 were retrospectively reviewed. Demographic, clinical, and follow-up data were retrieved from the medical charts. Metastases that were diagnosed during follow-up were recorded. RESULTS: Among the 481 patients with ILC, 74 (15.4%) were diagnosed with metastases after a median follow-up of 46 months. Among these 74 patients, 41.9% had metastases in atypical sites. Five patients were diagnosed with histologically confirmed gastric metastases of ILC. CONCLUSION: Metastases of breast ILC to atypical sites might be more frequent than previously reported. Clinicians should keep a high level of suspicion when a patient with a history of ILC develops digestive symptoms. It is important to differentiate metastases from a primary GI tumor by using immunohistochemical markers. J. Surg. Oncol. 2016;114:543-547. © 2016 Wiley Periodicals, Inc.