Expiratory Residual Volume Research Articles

Abstract 172: Ultra-Fast Cooling Through Total Liquid Ventilation is Safe and Feasible in Non-Human Primates

Introduction: Total liquid ventilation (TLV) with temperature-controlled perfluorocarbons (PFC) provides ultra-rapid and protective cooling in animal models of cardiac arrest. However, the ideal ventilatory parameters still need to be determined for a perfectly safe translation of the procedure in humans, especially regarding expiratory residual volume (RV) and tidal volume of PFC (TV) during TLV. Hypothesis: We hypothetised that TLV with low RV and TV of PFC is safe and efficient for ultra-fast cooling induction in non-human primates. Method: We enrolled two 13-years monkeys ( Macaca Fascicularis ) weighting 10.6 and 11.7 kg, respectively. Lung functional residual capacity (FRC) was measured by CT-scan and 3D-reconstruction of the lung. Two weeks later, animals were anesthetised and submitted to 20 min of TLV with end-expiratory volume of ≈50% of the FRC and TV = 8 ml/kg. The respiratory rate was set to 8/min and the target temperature was 33°C. After the TLV procedure, animals were weaned by prolonged exhalation followed by 6 hours under conventional mechanical ventilation (PEEP = 5 mmHg) before awakening. Three weeks later, they were ansthestized again for blood gases measurement and CT-scan examination for evaluation of the lung parenchyma integrity. Result: The initial CT-scan revealed a FRC of 26 and 32 ml/kg in the two animals, respectively. RV was then set at 15 ml/kg for TLV in both animals. During TLV, gas exchanges were normal (arterial partial pressure of CO 2 was 34 and 43 mmHg, respectively). Pulse oxymetry also remained above 97% throughout TLV. The target temperature of 33°C was achieved in the entire body within 15 min for both animals. Additionally, lung static compliance was not altered during or after TLV. After animal weaning, no any sign of respiratory discomfort was evidenced despite careful clinical monitoring. After three weeks, CT-scan examination revealed no structural abnormality of the lung parenchym and arterial partial pressure of CO 2 was normal (35 and 46 mmHg). Based on their excellent health status, animals were transferred to a rehabilitation center. Conclusion: Total liquid ventilation below FRC is feasible and safe, without any impairement of the cooling performance in a clinically relevant non-human primate model.

Fonction pulmonaire du patient diabétique

Diabetes mellitus is a disease affecting a lot of organs. One of the little known diabetes complication is impairment of pulmonary function. The aim of this study was to compare pulmonary function in two groups: diabetic individuals and obese non-diabetic individuals and to investigate predictive factors of alteration of diffusing capacity of lung for carbon monoxide (DLCO). We retrospectively included all patients hospitalized in department of endocrinology between 1st July 2013 and 31 December 2013 and who underwent pulmonary function tests. All these medical charts of patients were reviewed and patients were classified in two groups: diabetic and obese non-diabetic individuals. Overall, 89 patients were included, 62 diabetic patients and 27 obese non-diabetic patients. Forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), medium expiratory flow, expiratory residual volume, total lung capacity (TLC) and DLCO were significantly lower in patients with diabetes mellitus compared to obese non-diabetic patients. A low DLCO was significantly associated with diabetic neuropathy, macrovascular complication (carotid atheroma), impairment of renal function, and insulin treatment. Respiratory function is impaired in diabetes mellitus, with a significant decrease in FVC, FEV1, TLC and DLCO.

Effect of forward shoulder posture on pulmonary capacities of women

Objective:To evaluate if forward shoulder posture (FSP) would alter pulmonary capacities.Design and setting:A blinded, controlled design was used.Subjects:40 female subjects with FSP recruited from university students.Methods and main outcome measurements:Saggital...

Respiratory function in pregnancy at sea level and at high altitude.

To determine the effect of pregnancy on respiratory function in a non-Caucasian group and determine whether there was an interaction between pregnancy and altitude of residence. Prospective cross sectional study. Antenatal clinics in Peru, at sea level in Lima and at high altitude in Cerro de Pasco. Peruvian women with singleton pregnancies; 122 living at sea level and 192 living at 4300 m altitude in the Peruvian Andes. At each location, 19 non-pregnant women were also studied. Respiratory function was measured in pregnant and non-pregnant women living at sea level and at 4300 m. Forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), peak expiratory flow rate (PEFR), total lung capacity (TLC), inspiratory capacity (IC), residual volume (RV), expiratory residual volume (ERV) and functional residual capacity (FRC). At sea level, RV and TLC were higher in the third compared with the first trimester (P < 0.05). At high altitude, FEV1 (P < 0.01), ERV (P < 0.01) and FRC (P < 0.01) were lower in the third compared with the first trimester. Pregnant and non-pregnant women at high altitude were 4 cm shorter (P < 0.0001) and had larger lung volumes (P < 0.01); their total lung capacities were approximately 1 L greater than women living at sea level (P < 0.0001). These results suggest that the effect of pregnancy on the respiratory function of healthy women is influenced by altitude of residence.

Chest mechanics in morbidly obese non-hypoventilated patients

Seventy-seven patients with morbid obesity, body mass index (BMI) 40–69·9 kg m−2, who were candidates for gastroplasty, were studied in our laboratory as part of a pre-operative survey. They had no complaints other than obesity and were not cyanotic. A group of 28 lean subjects (BMI 20–29·8 kg m−2) who were candidates for abdominal surgery, without any respiratory complaint, were included as controls. For each patient a pulmonary function test was performed, measuring slow vital capacity with expiratory residual volume (ERV), forced vital capacity (flow/volume) and maximal voluntary ventilation (MVV).In obese patients the MVV is reduced as BMI increases. This results in the reduction of expiratory flows and volumes. Forced expiratory volume in 1 sec (FEV1) is reduced in proportion to the FVC reduction and is related to MVV. It is suggested that the main consequence of the burden of the chest wall by increased adipose mass is a reduction in its compliance, making inspiration increasingly difficult, and resulting in lower static volumes and flows.