Emmanuel Guerot

Effects of pressure-controlled with different I:E ratios versus volume-controlled ventilation on respiratory mechanics, gas exchange, and hemodynamics in patients with adult respiratory distress syndrome.

Background:Pressure-controlled (PCV) and pressure-controlled inverse ratio ventilation (PCIRV) have been proposed instead of volume-controlled conventional ratio ventilation (VC) with positive end-expiratory pressure (PEEP) for patients with adult respiratory distress syndrome (ARDS). The advantages advocated with the use of PCIRV are to decrease airway pressures and to improve gas exchange. However, most studies did not compare PCIRV and VC while keeping both the level of ventilation and end-expiratory alveolar pressure (total-PEEP) constant. Methods:Nine patients with moderate to severe ARDS (lung injury score 2.83 ± 0.18) had their lungs ventilated with VC, PCV with a conventional ratio (I:E 1:2; PC 1/2), and PCIRV (I: E 2:1 and 3:1; PC 2/1 and PC 3/1, respectively). Ventilator settings were adjusted to keep tidal volume, respiratory rate, Fio2, and total-PEEP constant in every mode. With each mode, a complete set of ventilatory, hemodynamic, and gas exchange parameters was obtained after 30 min. Results:In PC 3/1, the data obtained could not be strictly compared to the other modes because total-PEEP was higher despite external-PEEP being set at zero. For the other modes (VC, PC 1/2, and PC 2/1), despite differences in peak airway pressures, no difference was noted for end-inspiratory and end-expiratory static airway pressures (which better reflect alveolar pressures) nor for lung and respiratory system compliance. Arterial oxygenation deteriorated slightly with PC 2/1 despite a higher mean airway pressure, whereas alveolar ventilation tended to be slightly, but not significantly, improved (lower Paco2). A decrease in systolic and mean arterial pressure also was observed with PC 2/1 without other significant hemodynamic change. Conclusions:In this prospective controlled study, no short-term beneficial effect of PCV or PCIRV could be demonstrated over conventional VC with PEEP in patients with ARDS.

Clinically significant gastrointestinal bleeding in critically ill patients with and without stress-ulcer prophylaxis

ObjectiveTo compare the rates of clinically significant gastrointestinal bleeding and the number of blood units and endoscopies required for gastrointestinal hemorrhage between patients receiving or not receiving stress-ulcer prophylaxis.DesignHistorical observational study comparing two consecutive periods: with (phase 1) and without stress-ulcer prophylaxis (phase 2).Design and settingA 17-bed intensive care unit in a university teaching hospital.PatientsIn phase 1 there were 736 patients and in phase 2 737. Those in the two phases were comparable in age and reason for admission; clinically significant gastrointestinal bleeding rates did not differ between the two phases, but patients in phase 2 were more severely ill.Measurements and resultsComparable numbers of blood units were transfused per bleeding patient in the two phases, especially for patients with significant gastrointestinal bleeding. During each phase 19 fibroscopies were performed for significant bleeding, and two patients required surgery. The clinically significant gastrointestinal bleeding rate and outcome did not differ in patients with at least one risk factor. Total expenditures directly related to gastrointestinal bleeding were similar during the two phases; the total cost incurred by stress-ulcer prophylaxis was estimated at €6700.ConclusionsOur results suggest that stress-ulcer prophylaxis does not influence the clinically significant gastrointestinal bleeding rate in intensive care unit patients or the cost of its management.

Increased intensity of treatment and decreased mortality in elderly patients in an intensive care unit over a decade

Objectives:Data collected from two cohorts of patients aged ≥80 yrs and admitted to an intensive care unit in France were compared to determine whether intensive care unit care and survival had evolved from the 1990s to the 2000s. Design:Retrospective cohort study on patient data attained during intensive care unit stays. Setting:18-bed intensive care unit in an academic medical center. Patients:Two cohorts of patients aged ≥80 yrs, admitted to an intensive care unit at a 10-yr interval. Interventions:None. Measurements and Main Results:The first cohort comprised 348 patients admitted between January 1992 and December 1995, and the second cohort, 373 patients admitted between January 2001 and December 2004. There was no difference in age between the two cohorts, but patients in the second had significantly less history of functional limitation and significantly more acute illness (Simplified Acute Physiology Score II 43 ± 18 vs. 57 ± 25, respectively, p < .0001). Patients in the second cohort had a significantly higher Omega Score, had a higher occurrence of renal replacement therapy, and received vasopressors more frequently than the patients in the first cohort, even when adjusted for age, sex, Knaus classification, Simplified Acute Physiology Score II, and intensive care unit admission cause. Intensive care unit mortality was 65% and 64% for the first and second cohorts, respectively. In multivariate analysis (including age, Knaus classification, Simplified Acute Physiology Score II and first vs. second period) for association with intensive care unit survival, the 2001–2004 period was associated with a near tripling of chances of survival (odds ratio 2.9; 95% confidence interval, 1.92–4.47, p < .0001). Conclusions:The characteristics and intensity of treatment for elderly people admitted to the intensive care unit changed significantly over a decade. The intensity of treatments has increased over time and survival has improved over time as well. A potential link between increased treatment and improved survival in the elderly may be evoked.

Ultrasonographic Diagnostic Criterion for Severe Diaphragmatic Dysfunction After Cardiac Surgery

BACKGROUND Severe diaphragmatic dysfunction can prolong mechanical ventilation after cardiac surgery. An ultrasonographic criterion for diagnosing severe diaphragmatic dysfunction defined by a reference technique such as transdiaphragmatic pressure measurements has never been determined. METHODS Twenty-eight patients requiring mechanical ventilation > 7 days postoperatively were studied. Esophageal and gastric pressures were measured to calculate transdiaphragmatic pressure during maximal inspiratory effort and the Gilbert index, which evaluates the diaphragm contribution to respiratory pressure swings during quiet ventilation. Ultrasonography allowed measuring right and left hemidiaphragmatic excursions during maximal inspiratory effort. Best E is the greatest positive value from either hemidiaphragm. Twenty cardiac surgery patients with uncomplicated postoperative course were also evaluated with ultrasonography preoperatively and postoperatively. Measurements were performed in semirecumbent position. RESULTS Transdiaphragmatic pressure during maximal inspiratory effort was below normal value in 27 of the 28 patients receiving prolonged mechanical ventilation (median, 39 cm H(2)O; interquartile range [IQR] 28 cm H(2)O). Eight patients had Gilbert indexes <or= 0 indicating severe diaphragmatic dysfunction. Best E was lower in patients with Gilbert index <or= 0 than > 0 (30 mm; IQR, 10 mm; vs 19 mm; IQR, 7 mm, respectively; p = 0.001). Best E < 25 mm had a positive likelihood ratio of 6.7 (95% confidence interval [CI], 2.4 to 19) and a negative likelihood ratio of 0 (95% CI, 0 to 1.1) for having a Gilbert index <or= 0. None of the patients with uncomplicated course had Best E < 25 mm either preoperatively or postoperatively. CONCLUSIONS Ultrasonographic-based determination of hemidiaphragm excursions in patients requiring prolonged mechanical ventilation after cardiac surgery may help identify those with and without severe diaphragmatic dysfunction as defined by the Gilbert index.

Validation of a predictive method for an accurate assessment of resting energy expenditure in medical mechanically ventilated patients.

Objective:Use comparison with indirect calorimetry to confirm the ability of our previously described equation to predict resting energy expenditure in mechanically ventilated patients. Design:Prospective, validation study. Setting:Eighteen-bed, medical intensive care unit at a teaching hospital. Patients:All adult patients intubated >24 hrs were assessed for eligibility. Exclusion criteria were clinical situations that could contribute to erroneous calorimetric measurements. Interventions:Resting energy expenditure was calculated using the original Harris-Benedict equations and those corrected for usual stress factors, the Swinamer equation, the Fusco equation, the Ireton-Jones equation, and our equation: resting energy expenditure (kcal/day) = 8 × weight (kg) + 14 × height (cm) + 32 × minute ventilation (L/min) + 94 × temperature (°C) − 4834. Measurements and Main Results:Resting energy expenditure was measured by indirect calorimetry for the 45 included patients. Resting energy expenditure calculated with our predictive model correlated with the measured resting energy expenditure (r2 = .62, p < .0001), and Bland-Altman analysis showed a mean bias of −192 ± 277 kcal/day, with limits of agreement ranging from −735 to 351 kcal/day. Resting energy expenditure calculated with the Harris-Benedict equations was more weakly correlated with measured resting energy expenditure (r2 = .41, p < .0001), with Bland-Altman analysis showing a mean bias of 279 ± 346 kcal/day between them and the limits of agreement ranging from −399 to 957 kcal/day. Applying usual stress-correction factors to the Harris-Benedict equations generated wide variability, and the correlation with measured resting energy expenditure was poorer (r2 = .18, p < .0001), with Bland-Altman analysis showing a mean bias of −357 ± 750 kcal/day and limits of agreement ranging from −1827 to 1113 kcal/day. The use of the Swinamer, Fusco, or Ireton-Jones predictive methods yielded weaker correlation between calculated and measured resting energy expenditure (r2 = .41, p < .0001; r2 = .38, p < .0001; r2 = .39, p < .0001, respectively) than our equation, and Bland-Altman analysis showed no improvement in agreement and variability between methods. Conclusions:The Faisy equation, based on static (height), less stable (weight), and dynamic biometric variables (temperature and minute ventilation), provided precise and unbiased resting energy expenditure estimations in mechanically ventilated patients.

Two-Dimensional Strain Rate and Doppler Tissue Myocardial Velocities: Analysis by Echocardiography of Hemodynamic and Functional Changes of the Failed Left Ventricle during Different Degrees of Extracorporeal Life Support

BACKGROUND To evaluate hemodynamic and functional changes of the failed left ventricle by Velocity Vector Imaging (VVI) and tissue Doppler, 22 patients with cardiogenic shock supported by extracorporeal life support (ECLS) were imaged during ECLS output variations inducing severe load manipulations. METHODS The following data were acquired: (1) mean arterial pressure, aortic Doppler velocity-time integral, left ventricular end-diastolic volume, and mitral Doppler E wave; (2) tissue Doppler systolic (Sa) and early diastolic (Ea) velocities; and (3) systolic peak velocity (Sv), strain, and strain rate using VVI. RESULTS Load variations were documented by a significant decrease in afterload (mean arterial pressure, -21%), an increase in preload (left ventricular end-diastolic volume, +12%; E, +46%; E/Ea ratio, +22%), and an increase in the velocity-time integral (+45%). VVI parameters increased (Sv, +36%; strain, +81%; and strain rate, +67%; P < .05), unlike tissue Doppler systolic velocities (+2%; P = NS). Whatever the ECLS flow, Sa was higher in patients who survived. CONCLUSIONS VVI parameters are not useful in characterizing the failed left ventricle with rapidly varying load conditions. Tissue Doppler systolic velocities appear to be load independent and thus could help in the management of ECLS patients.

Helium/oxygen mixture reduces the work of breathing at the end of the weaning process in patients with severe chronic obstructive pulmonary disease.

ObjectiveTo test the hypothesis that helium/oxygen mixture can reduce the work of breathing at the end of the weaning process in patients with chronic obstructive pulmonary disease. DesignProspective, randomized, crossover study. SettingTwo medical intensive care units at two university tertiary care centers. PatientsThirteen patients with chronic obstructive pulmonary disease evaluated just before and after extubation. InterventionsHelium/oxygen and air/oxygen mixtures were administered sequentially, for 20 mins each, in a randomized order, just before extubation. It was possible to repeat the study after extubation in five patients. Measurements and Main ResultsBefore extubation, the helium/oxygen mixture induced no significant variation in the breathing pattern. By contrast, it reduced the work of breathing from 1.442 ± 0.718 J/L (mean ± sd) to 1.133 ± 0.500 J/L (p < .05). This reduction was explained mainly by a reduction in the resistive component of the work of breathing from 0.662 ± 0.376 to 0.459 ± 0.256 J/L (p < .01). We also observed a slight reduction in the intrinsic positive end-expiratory pressure from 2.9 ± 2.1 cm H2O to 2.1 ± 1.8 cm H2O (p < .05). Similar results were also observed after extubation in five patients in whom the repetition of the study was possible. ConclusionsIn spontaneously breathing intubated patients with chronic obstructive pulmonary disease recovering from an acute exacerbation, helium/oxygen mixture reduces the work of breathing as well as intrinsic positive end-expiratory pressure without modifying the breathing pattern.

Hyperoxia and hypertonic saline in patients with septic shock (HYPERS2S): a two-by-two factorial, multicentre, randomised, clinical trial

BACKGROUND There is insufficient research into the use of mechanical ventilation with increased inspiratory oxygen concentration (FiO2) and fluid resuscitation with hypertonic saline solution in patients with septic shock. We tested whether these interventions are associated with reduced mortality. METHODS This two-by-two factorial, multicentre, randomised, clinical trial (HYPERS2S) recruited patients aged 18 years and older with septic shock who were on mechanical ventilation from 22 centres in France. Patients were randomly assigned 1:1:1:1 to four groups by a computer generated randomisation list stratified by site and presence or absence of acute respiratory distress syndrome by use of permuted blocks of random sizes. Patients received, in an open-labelled manner, mechanical ventilation either with FiO2 at 1·0 (hyperoxia) or FiO2 set to target an arterial haemoglobin oxygen saturation of 88-95% (normoxia) during the first 24 h; patients also received, in a double-blind manner, either 280 mL boluses of 3·0% (hypertonic) saline or 0·9% (isotonic) saline for fluid resuscitation during the first 72 h. The primary endpoint was mortality at day 28 after randomisation in the intention-to-treat population. This study was registered with ClinicalTrials.gov, number NCT01722422. FINDINGS Between Nov 3, 2012, and June 13, 2014, 442 patients were recruited and assigned to a treatment group (normoxia [n=223] or hyperoxia [n=219]; isotonic [n=224] or hypertonic [n=218]). The trial was stopped prematurely for safety reasons. 28 day mortality was recorded for 434 patients; 93 (43%) of 217 patients had died in the hyperoxia group versus 77 (35%) of 217 patients in the normoxia group (hazard ratio [HR] 1·27, 95% CI 0·94-1·72; p=0·12). 89 (42%) of 214 patients had died in the hypertonic group versus 81 (37%) of 220 patients in the isotonic group (HR 1·19, 0·88-1·61; p=0·25). We found a significant difference in the overall incidence of serious adverse events between the hyperoxia (185 [85%]) and normoxia groups (165 [76%]; p=0·02), with a clinically relevant doubling in the hyperoxia group of the number of patients with intensive care unit-acquired weakness (24 [11%] vs 13 [6%]; p=0·06) and atelectasis (26 [12%] vs 13 [6%]; p=0·04) compared with the normoxia group. We found no statistical difference for serious adverse events between the two saline groups (p=0·23). INTERPRETATION In patients with septic shock, setting FiO2 to 1·0 to induce arterial hyperoxia might increase the risk of mortality. Hypertonic (3%) saline did not improve survival. FUNDING The French Ministry of Health.

High Prevalence of Respiratory Viral Infections in Patients Hospitalized in an Intensive Care Unit for Acute Respiratory Infections as Detected by Nucleic Acid-Based Assays

ABSTRACT Forty-seven bronchoalveolar lavages (BAL) were obtained from 41 patients with acute pneumonia attending an intensive care unit. By molecular diagnosis, 30% of total BAL and 63% of bacteria-negative BAL were positive for respiratory viruses. Molecular detection allows for high-rate detection of respiratory viral infections in adult patients suffering from severe pneumonia.

Drowning associated pneumonia: A descriptive cohort☆

PURPOSE Pneumonia is the most common infectious complication of drowning. Pneumonia is potentially life threatening and should be treated by effective antibiotic therapy. However the risk factors, microbiological causes, diagnostic approach and appropriate therapy for pneumonia associated with drowning are not well described. The microbiological ecology of the body of water where immersion occurred could be of import. The aim of this study was to report on microorganisms involved in pneumonia associated with drowning and out of hospital cardiac arrest after successful cardiopulmonary resuscitation. Additionally, we retrieved and undertook microbiological analysis on samples of water from our local river. METHODS This retrospective study included all patients having suffered an out of hospital cardiac arrest due to drowning and admitted to our tertiary care academic hospital between 2002 and 2010. Data concerning bacteriological lung samples (tracheal aspirate or bronchoalveolar lavage) at admission were reported and compared to bacteriological samples obtained from our local river (the river Seine). RESULTS A total of thirty-seven patients were included in the study. Lung samples were obtained for twenty-one of these patients. Lung samples were positive in nineteen cases, with a high frequency of multi-drug resistant bacteria. Samples from the Seine River found microorganisms similar to those found in drowning associated pneumonia. CONCLUSIONS Drowning associated pneumonia can be due to multi drug resistant bacteria. When treating drowning associated pneumonia, antibiotics should be effective against bacteria similar to those found in the body of water where immersion occurred.