The effects of airway pressure and inspiratory time on bacterial translocation.

BACKGROUND: Mechanical ventilation with high peak inspiratory pressure (PIP) induces lung injury and bacterial translocation from the lung into the systemic circulation. We investigated the effects of increased inspiratory time on translocation of intratracheally inoculated bacteria during mechanical ventilation with and without extrinsic positive end-expiratory pressure (PEEP). METHODS: Rats were ventilated in pressure-controlled mode with 14 cm H2O PIP, 0 cm H2O PEEP, I:E ratio 1/2, and Fio2 1.0. Subsequently, 0.5 mL of 10(5) cfu/mL Pseudomonas aeruginosa was inoculated through tracheostomy and rats were randomly assigned to six groups; two low-pressure groups (LP)1/2, 14 cm H2O PIP, 0 cm H2O PEEP, I:E = 1/2, and LP2/1 14 cm H2O PIP, 0 cm H2O PEEP, I:E = 2/1; two high-pressure groups (HP)1/2, 30 cm H2O PIP, 0 cm H2O PEEP, I:E = 1/2, and HP2/1, 30 cm H2O PIP, 0 cm H2O PEEP, I:E = 2/1; two HP PEEP groups (HPP)1/2, 30 cm H2O PIP, 10 cm H2O PEEP, I:E = 1/2, and HPP2/1, 30 cm H2O PIP, 10 cm H2O PEEP, I:E = 2/1. Blood cultures were obtained every 30 min. The rats were killed and their lungs were processed. RESULTS: When compared with baseline values, Pao2 decreased in the LP1/2, LP2/1, HP1/2, and HP2/1 groups at the last time point, but the decline in Pao2 reached statistical significance in only the HP1/2 group. The bacterial translocation rate was greater in group HPP2/1 than group HPP1/2 (P = 0.01). CONCLUSIONS: We found that high PIP, with or without prolonged inspiratory time, increased the rate of bacterial dissemination. PEEP prevented bacterial translocation in the high PIP group. However, the protective effect of PEEP was lost when inspiratory time was prolonged.

Assessment of the success of cardiopulmonary resuscitation attempts performed in a Turkish university hospital.

The success rate of cardiopulmonary resuscitation (CPR) may differ from institution to institution, even within different sites in the same institution. A variety of factors may influence the outcome. In this study, we assessed the adequacy of CPR attempts guided by the current standards and aimed to define the factors influencing the outcome following in-hospital cardiac arrest. One hundred and thirty-four patients who required CPR were studied prospectively. Different variables for the CPR performance were recorded using forms designed for this study in the light of the guidelines. In these CPR forms various data including the demographics, history, monitoring, number, composition and experience of the anaesthesiologists, the site of CPR, time of day, the delay before onset of CPR, tracheal intubation, duration of arrest, initial rhythm in ECG monitored patients, management of CPR, drug administration and reversible causes of cardiac arrest were recorded. Our rates of immediate survival, survival at 24 h and survival to discharge 49.3%, 28.5% and 13.4%, respectively. The extent of monitoring prior to arrest, the attendance of one or more experienced anesthesiologists in the CPR team, CPR during office hours, CPR in ICU or operating room, early initiation of CPR and tracheal intubation prior to arrest were found as the factors increasing discharge survival. We conclude that early initiation of CPR with an experienced team in a well-equipped hospital sites increases the discharge survival rate following cardiac arrest.

Time required for equilibration of arterial oxygen pressure after setting optimal positive end-expiratory pressure in acute respiratory distress syndrome.

OBJECTIVE: To evaluate the time course of Pao2 change following the setting of optimal positive end-expiratory pressure (PEEP) in patients with acute respiratory distress syndrome (ARDS). DESIGN: Prospective clinical study. SETTING: Multidisciplinary intensive care unit of a university hospital. PATIENTS: Twenty-five consecutive patients with ARDS. INTERVENTIONS: ARDS was diagnosed during pressure-regulated volume control ventilation with tidal volume of 7 mL/kg actual body weight, respiratory rate of 12 breaths/min, inspiratory/expiratory ratio of 1:2, Fio2 of 1, and PEEP of 5 cm H2O. A critical care attending physician obtained pressure volume curves and determined the lower inflection point. Following a rest period of 30 mins with initial ventilation variables, PEEP was set at 2 cm H2O above the lower inflection point, and serial blood samples were collected during 1-hr ventilation with optimal PEEP. Arterial blood gas analyses were performed at 1, 3, 5, 7, 9, 11, 15, 20, 30, 45, and 60 mins. MEASUREMENTS AND MAIN RESULTS: Twenty-five patients were found eligible for the study. Three patients were excluded due to deterioration of oxygen saturation and hemodynamic instability following the initiation of optimal PEEP. Eight cases (36%) were considered to be of pulmonary origin and 14 cases (64%) of extrapulmonary origin. Optimal PEEP levels were 14 +/- 3 cm H2O and 14 +/- 4 cm H2O in pulmonary and extrapulmonary ARDS, respectively. Pao2 demonstrated a 130 +/- 101% increase at the end of 1-hr period in total study population. This improvement did not differ significantly between pulmonary and extrapulmonary forms of ARDS (135 +/- 118% vs. 127 +/- 95%, p = .8). Mean 90% oxygenation time was found to be 20 +/- 19 mins. In the subset of patients with ARDS of pulmonary origin, 90% oxygenation time was 25 +/- 26 mins, whereas it was 17 +/- 15 mins in patients with ARDS of extrapulmonary origin (p = .8). CONCLUSIONS: Our data showed that 20 mins would be adequate for obtaining a blood gas sample in ARDS patients with pulmonary and extrapulmonary origin after application of optimal PEEP 2 cm H2O above the lower inflection point.

Effects of sustained inflation and postinflation positive end-expiratory pressure in acute respiratory distress syndrome: focusing on pulmonary and extrapulmonary forms.

OBJECTIVE: To investigate whether the response to sustained inflation and postinflation positive end-expiratory pressure varies between acute respiratory distress syndrome with pulmonary (ARDS(exp)) and extrapulmonary origin (ARDS(exp)). DESIGN: Prospective clinical study. SETTING: Multidisciplinary intensive care unit in a university hospital. PATIENTS: A total of 11 patients with ARDS and 13 patients with ARDS. INTERVENTIONS: A 7 ml/kg tidal volume, 12-15 breaths/min respiratory rate, and an inspiratory/expiratory ratio of 1:2 was used during baseline ventilation. Positive end-expiratory pressure levels were set according to the decision of the primary physician. Sustained inflation was performed by 45 cm H2O continuous positive airway pressure for 30 secs. Postinflation positive end-expiratory pressure was titrated decrementally, starting from a level of 20 cm H2O to keep the peripheral oxygen saturation between 92% and 95%. Fio2 was decreased, and baseline tidal volume, respiratory rate, inspiratory/expiratory ratio were maintained unchanged throughout the study period. MEASUREMENTS AND MAIN RESULTS: Blood gas, airway pressure, and hemodynamic measurements were performed at the following time points: at baseline and at 15 mins, 1 hr, 4 hrs, and 6 hrs after sustained inflation. After sustained inflation, the Pao2/Fio2 ratio improved in all of the patients both in ARDS(p) and ARDS(exp). However, the Pao2/Fio2 ratio increased to >200 in four ARDS(p) patients (36%) and in seven ARDS(p) patients (54%). In two of those ARDS patients, the Pao2/Fio2 ratio was found to be <200, whereas none of the ARDS(p) patients revealed Pao2/Fio2 ratios of <200 at the 6-hr measurement. Postinflation positive end-expiratory pressure levels were set at 16.7 +/- 2.3 cm H O in ARDS(p) and 15.6 +/- 2.5 cm H2O in ARDS. The change in Pao /Fio ratios was found statistically significant in patients with ARDS(p) (p =.0001) and with ARDS(p) (p =.008). Respiratory system compliance increased in ARDS patients (p =.02), whereas the change in ARDS was not statistically significant. CONCLUSIONS: Sustained inflation followed by high levels of postinflation positive end-expiratory pressure provided an increase in respiratory system compliance in ARDS; however, arterial oxygenation improved in both ARDS forms.

[Is jejunal feeding efficient in critically ill patients?]. / Kritik hastada jejunal beslenme etkin midir?

BACKGROUND: The aim of this study is to compare the results of jejunal and gastric nutrition in the ICU. METHODS: Caloric intake and nutritional complications were recorded for ten days period in patients receiving gastric (n = 21) and jejunal (n = 22) feeding. RESULTS: Caloric requirements were reached on the 3rd day of nutrition in 86% of jejunal and 28% of gastric feeding patients (p 0.001). In jejunal group, delivered calorie/goal calorie ratio was found 15-20% higher than the gastric group. Serum albumin, triglyceride, cholesterol levels and nitrogen balance did not show significant differences between groups. Vomiting (p 0.01) and colouring of tracheal aspirates (p 0.05) were more frequent in gastric group, however positive tracheal culture frequency did not differ between the groups. CONCLUSION: It is concluded that higher caloric intakes could be tolerated earlier in patients receiving jejunal feeding.