Daniel Deheinzelin

Effect of a Protective-Ventilation Strategy on Mortality in the Acute Respiratory Distress Syndrome

BACKGROUND In patients with the acute respiratory distress syndrome, massive alveolar collapse and cyclic lung reopening and overdistention during mechanical ventilation may perpetuate alveolar injury. We determined whether a ventilatory strategy designed to minimize such lung injuries could reduce not only pulmonary complications but also mortality at 28 days in patients with the acute respiratory distress syndrome. METHODS We randomly assigned 53 patients with early acute respiratory distress syndrome (including 28 described previously), all of whom were receiving identical hemodynamic and general support, to conventional or protective mechanical ventilation. Conventional ventilation was based on the strategy of maintaining the lowest positive end-expiratory pressure (PEEP) for acceptable oxygenation, with a tidal volume of 12 ml per kilogram of body weight and normal arterial carbon dioxide levels (35 to 38 mm Hg). Protective ventilation involved end-expiratory pressures above the lower inflection point on the static pressure-volume curve, a tidal volume of less than 6 ml per kilogram, driving pressures of less than 20 cm of water above the PEEP value, permissive hypercapnia, and preferential use of pressure-limited ventilatory modes. RESULTS After 28 days, 11 of 29 patients (38 percent) in the protective-ventilation group had died, as compared with 17 of 24 (71 percent) in the conventional-ventilation group (P<0.001). The rates of weaning from mechanical ventilation were 66 percent in the protective-ventilation group and 29 percent in the conventional-ventilation group (P=0.005): the rates of clinical barotrauma were 7 percent and 42 percent, respectively (P=0.02), despite the use of higher PEEP and mean airway pressures in the protective-ventilation group. The difference in survival to hospital discharge was not significant; 13 of 29 patients (45 percent) in the protective-ventilation group died in the hospital, as compared with 17 of 24 in the conventional-ventilation group (71 percent, P=0.37). CONCLUSIONS As compared with conventional ventilation, the protective strategy was associated with improved survival at 28 days, a higher rate of weaning from mechanical ventilation, and a lower rate of barotrauma in patients with the acute respiratory distress syndrome. Protective ventilation was not associated with a higher rate of survival to hospital discharge.

Effect of acute kidney injury on weaning from mechanical ventilation in critically ill patients.

Objectives: Acute kidney injury (AKI) worsens outcome in various scenarios. We sought to investigate whether the occurrence of AKI has any effect on weaning from mechanical ventilation. Design and Setting: Observational, retrospective study in a 23‐bed medical/surgical intensive care unit (ICU) in a cancer hospital from January to December 2003. Patients: The inclusion criterion was invasive mechanical ventilation for ≥48 hrs. AKI was defined as at least one measurement of serum creatinine of ≥1.5 mg/dL during the ICU stay. Patients were then separated into AKI and non‐AKI patients (control group). The criterion for weaning was the combination of positive end‐expiratory pressure of ≤8 cm H2O, pressure support of ≤10 cm H2O, and Fio2 of ≤0.4, with spontaneous breathing. The primary end point was duration of weaning and the secondary end points were rate of weaning failure, total length of mechanical ventilation, length of stay in the ICU, and ICU mortality. Results: A total of 140 patients were studied: 93 with AKI and 47 controls. The groups were similar in regard to age, sex, and type of tumor. Diagnosis of acute lung injury/acute respiratory distress syndrome as cause of respiratory failure and Simplified Acute Physiology Score II at admission did not differ between groups. During ICU stay, AKI patients had markers of more severe disease: increased occurrence of severe sepsis or septic shock, higher number of antibiotics, and longer use of vasoactive drugs. The median (interquartile range) duration of mechanical ventilation (10 [6–17] vs. 7 [2–12] days, p = .017) and duration of weaning from mechanical ventilation (41 [16–97] vs. 21 [7–33.5] hrs, p = .018) were longer in AKI patients compared with control patients. Cox regression analysis demonstrated that a ≥85% increase in baseline serum creatinine (hazard rate, 2.30; 95% confidence interval, 1.30–4.08), oliguria (hazard rate, 2.51; 95% confidence interval, 1.24–5.08), and the number of antibiotics (hazard rate, 2.64; 95% confidence interval, 1.51–4.63) predicted longer duration of weaning. The length of ICU stay and ICU mortality rate were significantly greater in the AKI patients. After adjusting for Simplified Acute Physiology Score II, oliguria (odds ratio, 30.8; 95% confidence interval, 7.7–123.0) remained as a strong risk factor for mortality. Conclusion: This study shows that renal dysfunction has serious consequences in the duration of mechanical ventilation, weaning from mechanical ventilation, and mortality in critically ill cancer patients.

Inspiratory muscle training is ineffective in mechanically ventilated critically ill patients

PURPOSE Invasive mechanical ventilation is associated with complications, and its abbreviation is desirable. The imbalance between increased workload, decreased inspiratory muscle strength and endurance is an important determinant of ventilator dependence. Low endurance may be present due to respiratory muscle atrophy, critical illness, or steroid use. Specific inspiratory muscle training may increase or preserve endurance. The objective of the study was to test the hypothesis that inspiratory muscle training from the beginning of mechanical ventilation would abbreviate the weaning duration and decrease reintubation rate. As a secondary objective, we described the evolution of inspiratory muscle strength with and without inspiratory muscle training. METHODS Prospective, randomized clinical trial in an adult clinical-surgical intensive care unit. Twelve patients trained the inspiratory muscles twice a day, and 13 patients did not (control). Training was performed adjusting the sensitivity of the ventilator based on the maximal inspiratory pressure. Patients underwent daily surveillance of the maximal inspiratory pressure. RESULTS The weaning duration (31 +/- 22 hr, control and 23 +/- 11 hr, training group; P = .24) and reintubation rate (5 control and 3 training group; P = .39) were not statistically different. The maximal inspiratory pressure of the control group showed a trend toward a modest increase. In contrast, the training group showed a small decrease (P = .34). CONCLUSIONS In acute critically ill patients, inspiratory muscle training from the beginning of mechanical ventilation neither abbreviated the weaning duration, nor decreased the reintubation rate. Inspiratory muscle strength tended to stay constant, along the mechanical ventilation, with or without this specific inspiratory muscle training.

Saline instillation before tracheal suctioning decreases the incidence of ventilator-associated pneumonia

Objectives:To compare the incidence of ventilator-associated pneumonia (VAP) with or without isotonic saline instillation before tracheal suctioning. As a secondary objective, we compared the incidence of endotracheal tube occlusion and atelectasis. Design:Randomized clinical trial. Setting and Patients:The study was conducted in a medical surgical intensive care unit of an oncologic hospital. We selected consecutive patients needing mechanical ventilation for >72 hrs. Patients were allocated into two groups: a saline group that received instillation of 8 mL of saline before tracheal suctioning and a control group which did not. VAP was diagnosed based on clinical suspicion and confirmed by bronchoalveolar lavage quantitative culture. The incidence of atelectasis on daily chest radiography and endotracheal tube occlusions were recorded. The sample size was calculated to a power of 80% and a type I error probability of 5%. Measurements and Main Results:One hundred thirty patients were assigned to the saline group and 132 to the control group. The baseline demographic variables were similar between groups. The rate of clinically suspected VAP was similar in both groups. The incidence of microbiological proven VAP was significantly lower in the saline group (23.5% × 10.8%; p = 0.008) (incidence density/1.000 days of ventilation 21.22 × 9.62; p < 0.01). Using the Kaplan-Meier curve analysis, the proportion of patients remaining without VAP was higher in the saline group (p = 0.02, log-rank test). The relative risk reduction of VAP in the saline instillation group was 54% (95% confidence interval, 18%–74%) and the number needed to treat was eight (95% confidence interval, 5–27). The incidence of atelectases and endotracheal tube occlusion were similar between groups. Conclusions:Instillation of isotonic saline before tracheal suctioning decreases the incidence of microbiological proven VAP.

When to remove a chest tube? ☆: A randomized study with subsequent prospective consecutive validation

BACKGROUND Operative procedures on the pleural space are usually managed by chest tube drainage. Timing for removing the tube is empirically established, with wide variation among surgeons. Our objective was to evaluate the effectiveness and safety of establishing a volume of 200 mL/d of uninfected drainage as a threshold for removal of chest tube, as compared with more frequently used volumes of 100 and 150 mL/d. STUDY DESIGN A prospective randomized study was performed in a single institution. Patients (n = 139) submitting to pleural drainage after surgical procedures were randomized to one of three groups, defined by the planned timing of chest tube removal (depending on the threshold volume per day of pleural fluid drained): G-100 (< or = 100 mL/d, n = 44); G-150 (< or =150 mL/d, n = 58); and G-200 (< or = 200 mL/d, n = 37). Subsequently, another 91 consecutive patients had chest tubes removed when drainage was less than 200 mL/d (G-val, prospective validation group). All patients had similar discharge and 60-day followup. Drainage time, hospital stay, and reaccumulation rate were registered. RESULTS Drainage time (median days: 3.5 for G-100, 3 for G-150, 3 for G-200, 3 for G-val) and hospital stay (median days: 4 for G-100, 3 for G-150, 3 for G-200, 3 for G-val) were not statistically different among groups. Radiologic reaccumulation rates were 9.1% for G-100, 13.1% for G-150, 5.4% for G-200, and 10.9% for G-val, and the thoracenteses rates were 2.3%, 0.8%, 2.7%, and 3.3%, respectively, with no major differences among groups (G-100 versus G-150 versus G-200; G-200 versus G-val). CONCLUSIONS Increasing the threshold of daily drainage to 200 mL before removing the chest tube did not markedly affect drainage, hospitalization time, or overall costs, nor did it increase the likelihood of major pleural fluid reaccumulation. This volume (200 mL/d) could be recommended for chest tube withdrawal decision for uninfected pleural fluid with no evidence of air leaks.

Centrilobular Fibrosis: A Novel Histological Pattern of Idiopathic Interstitial Pneumonia

The classification of idiopathic interstitial pneumonias (IIP) is still under debate. In this context, we observed in some of our patients with a clinical and radiological diagnosis of IIP a different histological picture with an aggressive centrilobular scarring centered in the bronchiolar epithelia, but involving the surrounding parenchyma, which underwent extensive remodeling. We hypothesized that this pattern is a form of IIP that could be separated out histologically from the previously described patterns, in particular from usual interstitial pneumonia (UIP) and non-specific interstitial pneumonia (NSIP). Forty-nine patients with clinical and radiological diagnosis of IIP and open-lung biopsies were retrospectively selected from 1982 to 1998. The biopsies were reviewed according to the following criteria: derangement of lobular architecture, temporal homogeneity and subpleural or bronchocentric distribution of the lesions, fibroblast foci, bronchial epithelium necrosis and regeneration, exposure of the basal membrane, squamous metaplasia, basophilic intraluminal contents, and foreign bodies within the remodeling airspaces. Three groups were found: UIP (24 patients), NSIP (13), and a third that we named centrilobular fibrosis (CLF) (12). All histological parameters were significantly different among the three groups (p < 0.001). CLF is a specific, homogeneous, and recognizable histological pattern of IIP, and can be isolated from UIP and NSIP.

Families' interactions with physicians in the intensive care unit: the impact on family's satisfaction ☆

PURPOSE The objective of this study is to correlate the levels of satisfaction of family members, with their perception of the way information was offered and assistance delivered during the patients stay in the intensive care unit (ICU). MATERIALS AND METHODS This is a prospective study conducted in a 13-bed mixed ICU in a tertiary cancer. Family members were enrolled 2 days after admission if the patient remained in the ICU. Questions derived from a previous study assessed the quality of the information and support received (Crit Care Med 1998; 26:1187). To generate the satisfaction criteria, families fulfilled a Portuguese version of the Critical Care Family Needs Inventory. RESULTS One hundred sixty-four families were interviewed between May 2002 and May 2003. Insufficient information concerning the consequences of disease was a determinant of dissatisfaction (odds ratio [OR], 3.35; confidence interval [CI], 1.3-8.8), as well as insufficient information given by the ICU doctors (OR, 3.85; CI, 1.2-12.2). Accessibility of doctors was a major determinant of dissatisfaction when considered inadequate (OR, 6.92; CI, 2.3-20.6), and it was associated to a conflict regarding prognosis (P = .017). CONCLUSION Family satisfaction and understanding in the ICU may improve if the doctors are more accessible to provide information and the staff strive to better explain the patients condition.

Surgical resection of unilateral lung metastases: is bilateral thoracotomy necessary?

Abstracturgical resection of lung mestastases is routine procedure for selected patients with pulmonary nodules and solid tumors. In some cases, patients present with unilateral pulmonary metastases amenable to surgical resection. Surgeons are still divided between unilateral approach directed to the radiologically detected nodules, or bilateral exploratory thoracotomy. This study evaluates the need for bilateral thoracotomy in patients diagnosed with unilateral lung metastases. A retrospective evaluation was made of a prospective database from a single institution (1990–1997) of all consecutive patients (n = 267) diagnosed on admission with unilateral (n = 179) or bilateral (n= 88) lung nodules. Ipsilateral thoracotomy was performed on all patients with unilateral disease. Bilateral thoracotomy was performed on all patients with bilateral lung metastases. Histology: adenocarcinoma (25%), osteosarcoma (23%), squamous cell carcinoma (18%), soft-tissue sarcoma (18%), and other (16%). Median follow-up was 17 months. Contralateral disease-free survival and overall survival were determined. Univariate and multivariate analyses were performed to determine prognostic factors for overall and contralateral disease-free survival. The two groups of patients with confirmed bilateral metastases (synchronous or metachronous) were compared. Actuarial overall 5-year survival was 34.9%. Contralateral recurrence-free 6-month, 12-month, and 5-year survival were 95%, 89%, and 78%, respectively. Patients who experienced recurrence in the contralateral lung within 3, 6, or 12 months had an overall 5-year survival rate of 24%, 30%, and 37%, respectively. When patients with recurrence in the contralateral lung were compared to patients with bilateral metastases on admission, there was no significant difference in overall survival. Only histology and the number of pathologically proven metastases significantly (p <0.05) predicted recurrence in the contralateral lung. Bilateral exploration of unilateral lung metastases is not warranted in all cases. Most patients will have only unilateral disease, and delaying contralateral thoracotomy until disease is detected radiologically does not appear to affect outcome.

Pleurodesis in Patients with Malignant Pleural Effusions: Talc Slurry or Bleomycin? Results of a Prospective Randomized Trial

The purpose of this study was to evaluate the efficacy, safety, and cost of bedside pleurodesis for malignant pleural effusions using talc slurry (TS) or bleomycin (BL) in a prospective randomized trial, and to determine prognosticators for procedure failure. From June 1997 to June 1999 a series of 71 patients entered this trial. They underwent 37 procedures with TS (4 g) and 34 with BL (60 units) via tube thoracostomy. Success was defined as no recurrence of pleural effusion or asymptomatic recurrence of a small amount of effusion. Pleural effusion-free survival curves were used to analyze the success rates and the prognosticators of failure. Follow-up ranged from 3 days to 26 months (median 2.5 months). No difference in success rates was detected between TS or BL (log-rank test: p = 0.724). There were no major complications related to the procedure. The independent prognosticators of failed pleurodesis were the use of steroids (p = 0.004) and the volume of pleural fluid drained during the first thoracentesis when it was more than 900 ml (p = 0.029). The average cost of intervention per patient was significantly lower for TS (p < 0.001). There was no significant difference between the success rates for TS and BL as agents of bedside pleurodesis for malignant pleural effusions. Because of its significantly lower cost, TS should be considered the agent of choice. The use of steroids and the volume drained during the first thoracentesis (if more than 900 ml) were independent prognosticators of pleurodesis failure. The role of this latter finding as a marker of pleurodesis failure awaits more data.

What increases type III procollagen mRNA levels in lung tissue: stress induced by changes in force or amplitude?

We hypothesized that stress determined by force could induce higher type III procollagen (PCIII) mRNA expression than the stress determined by amplitude. To that end, rat lung tissue strips were oscillated for 1h under different amplitudes [1, 5 and 10% of resting length (L(B)), at 0.5 x 10(-2) N] and forces (0.25 x 10(-2), 0.5 x 10(-2) and 10(-2)N, at 5% L(B)). Resistance (R), elastance (E) and hysteresivity (eta) were analysed during sinusoidal oscillations at 1Hz. After 1h of oscillation, PCIII mRNA expression was determined by Northern-blot and semiquantitative RT-PCR. Control value of PCIII mRNA was obtained from unstressed strips. E and R increased with augmenting force and decreased with increasing amplitude, while eta remained unaltered. PCIII mRNA expression increased significantly after 1h of oscillation at 10(-2)N and 5% L(B) and remained unchanged for 6h. In conclusion, the stress induced by force but not by amplitude led to the increment in PCIII mRNA expression.