Guillaume Carteaux

Zika Virus Associated with Meningoencephalitis

As Zika virus spreads, the associated clinical syndromes need to be defined. In this report, an 81-year-old man is found to have Zika virus–associated meningoencephalitis.

Patient-Ventilator Asynchrony During Noninvasive Ventilation: A Bench and Clinical Study

BACKGROUND Different kinds of ventilators are available to perform noninvasive ventilation (NIV) in ICUs. Which type allows the best patient-ventilator synchrony is unknown. The objective was to compare patient-ventilator synchrony during NIV between ICU, transport—both with and without the NIV algorithm engaged—and dedicated NIV ventilators. METHODS First, a bench model simulating spontaneous breathing efforts was used to assess the respective impact of inspiratory and expiratory leaks on cycling and triggering functions in 19 ventilators. Second, a clinical study evaluated the incidence of patient-ventilator asynchronies in 15 patients during three randomized, consecutive, 20-min periods of NIV using an ICU ventilator with and without its NIV algorithm engaged and a dedicated NIV ventilator. Patient-ventilator asynchrony was assessed using flow, airway pressure, and respiratory muscles surface electromyogram recordings. RESULTS On the bench, frequent auto-triggering and delayed cycling occurred in the presence of leaks using ICU and transport ventilators. NIV algorithms unevenly minimized these asynchronies, whereas no asynchrony was observed with the dedicated NIV ventilators in all except one. These results were reproduced during the clinical study: The asynchrony index was significantly lower with a dedicated NIV ventilator than with ICU ventilators without or with their NIV algorithm engaged (0.5% [0.4%-1.2%] vs 3.7% [1.4%-10.3%] and 2.0% [1.5%-6.6%], P < .01), especially because of less auto-triggering. CONCLUSIONS Dedicated NIV ventilators allow better patient-ventilator synchrony than ICU and transport ventilators, even with their NIV algorithm. However, the NIV algorithm improves, at least slightly and with a wide variation among ventilators, triggering and/or cycling off synchronization.

Esophageal and transpulmonary pressure in the clinical setting: meaning, usefulness and perspectives

PurposeEsophageal pressure (Pes) is a minimally invasive advanced respiratory monitoring method with the potential to guide management of ventilation support and enhance specific diagnoses in acute respiratory failure patients. To date, the use of Pes in the clinical setting is limited, and it is often seen as a research tool only.MethodsThis is a review of the relevant technical, physiological and clinical details that support the clinical utility of Pes.ResultsAfter appropriately positioning of the esophageal balloon, Pes monitoring allows titration of controlled and assisted mechanical ventilation to achieve personalized protective settings and the desired level of patient effort from the acute phase through to weaning. Moreover, Pes monitoring permits accurate measurement of transmural vascular pressure and intrinsic positive end-expiratory pressure and facilitates detection of patient–ventilator asynchrony, thereby supporting specific diagnoses and interventions. Finally, some Pes-derived measures may also be obtained by monitoring electrical activity of the diaphragm.ConclusionsPes monitoring provides unique bedside measures for a better understanding of the pathophysiology of acute respiratory failure patients. Including Pes monitoring in the intensivist’s clinical armamentarium may enhance treatment to improve clinical outcomes.

Results of noninvasive ventilation in very old patients

BackgroundNoninvasive ventilation (NIV) is frequently used for the management of acute respiratory failure (ARF) in very old patients (≥ 80 years), often in the context of a do-not-intubate order (DNI). We aimed to determine its efficacy and long-term outcome.MethodsProspective cohort of all patients admitted to the medical ICU of a tertiary hospital during a 2-year period and managed using NIV. Characteristics of patients, context of NIV, and treatment intensity were compared for very old and younger patients. Six-month survival and functional status were assessed in very old patients.ResultsDuring the study period, 1,019 patients needed ventilatory support and 376 (37%) received NIV. Among them, 163 (16%) very old patients received ventilatory support with 60% of them managed using NIV compared with 32% of younger patients (p < 0.0001). Very old patients received NIV more frequently with DNI than in younger patients (40% vs. 8%). Such cases were associated with high mortality for both very old and younger patients. Hospital mortality was higher in very old than in younger patients but did not differ when NIV was used for cardiogenic pulmonary edema or acute-on-chronic respiratory failure (20% vs. 15%) and in postextubation (15% vs. 17%) out of a context of DNI. Six-month mortality was 51% in very old patients, 67% for DNI patients, and 77% in case of NIV failure and endotracheal intubation. Of the 30 hospital survivors, 22 lived at home and 13 remained independent for activities of daily living.ConclusionsVery old patients managed using NIV have an overall satisfactory 6-month survival and functional status, except for endotracheal intubation after NIV failure.

Bedside adjustment of proportional assist ventilation to target a predefined range of respiratory effort.

Objectives:During proportional assist ventilation with load-adjustable gain factors, peak respiratory muscle pressure can be estimated from the peak airway pressure and the percentage of assistance (gain). Adjusting the gain can, therefore, target a given level of respiratory effort. This study assessed the clinical feasibility of titrating proportional assist ventilation with load-adjustable gain factors with the goal of targeting a predefined range of respiratory effort. Design:Prospective, multicenter, clinical observational study. Settings:Intensive care departments at five university hospitals. Patients:Patients were included after meeting simple criteria for assisted mechanical ventilation. Interventions:Patients were ventilated in proportional assist ventilation with load-adjustable gain factors. The peak respiratory muscle pressure, estimated in cm H2O as (peak airway pressure – positive end-expiratory pressure) × [(100 – gain)/gain], was calculated from a grid at the bedside. The gain adjustment algorithm was defined to target a peak respiratory muscle pressure between 5 and 10 cm H2O. Additional recommendations were available in case of hypoventilation or hyperventilation. Results:Fifty-three patients were enrolled. Median time spent under proportional assist ventilation with load-adjustable gain factors was 3 days (interquartile range, 1–5). Gain was adjusted 1.0 (0.7–1.8) times per day, according to the peak respiratory muscle pressure target range in 91% of cases and because of hypoventilation or hyperventilation in 9%. Thirty-four patients were ventilated with proportional assist ventilation with load-adjustable gain factors until extubation, which was successful in 32. Eighteen patients required volume assist-controlled reventilation because of clinical worsening and need for continuous sedation. One patient was intolerant to proportional assist ventilation with load-adjustable gain factors. Conclusions:This first study assessing the clinical feasibility of titrating proportional assist ventilation with load-adjustable gain factors in an attempt to target a predefined range of effort showed that adjusting the level of assistance to maintain a predefined boundary of respiratory muscle pressure is feasible, simple, and often sufficient to ventilate patients until extubation.

Effects of Pleural Effusion Drainage on Oxygenation, Respiratory Mechanics, and Hemodynamics in Mechanically Ventilated Patients

OBJECTIVES In mechanically ventilated patients, the effect of draining pleural effusion on oxygenation is controversial. We investigated the effect of large pleural effusion drainage on oxygenation, respiratory function (including lung volumes), and hemodynamics in mechanically ventilated patients after ultrasound-guided drainage. Arterial blood gases, respiratory mechanics (airway, pleural and transpulmonary pressures, end-expiratory lung volume, respiratory system compliance and resistance), and hemodynamics (blood pressure, heart rate, and cardiac output) were recorded before and at 3 and 24 hours (H24) after pleural drainage. The respiratory settings were kept identical during the study period. MEASUREMENTS AND MAIN RESULTS The mean volume of effusion drained was 1,579 ± 684 ml at H24. Uncomplicated pneumothorax occurred in two patients. Respiratory mechanics significantly improved after drainage, with a decrease in plateau pressure and a large increase in end-expiratory transpulmonary pressure. Respiratory system compliance, end-expiratory lung volume, and PaO2/FiO2 ratio all improved. Hemodynamics were not influenced by drainage. Improvement in the PaO2/FiO2 ratio from baseline to H24 was positively correlated with the increase in end-expiratory lung volume during the same time frame (r = 0.52, P = 0.033), but not with drained volume. A high value of pleural pressure or a highly negative transpulmonary pressure at baseline predicted limited lung expansion following effusion drainage. A lesser improvement in oxygenation occurred in patients with ARDS. CONCLUSIONS Drainage of large (≥500 ml) pleural effusion in mechanically ventilated patients improves oxygenation and end-expiratory lung volume. Oxygenation improvement correlated with an increase in lung volume and a decrease in transpulmonary pressure, but was less so in patients with ARDS.

Effect of pressure support on end-expiratory lung volume and lung diffusion for carbon monoxide.

Objectives:The level of pressure-support ventilation can affect mean airway pressure and potentially lung volume, but its increase is usually associated with a reduced respiratory rate, and the net effects on the gas exchange process and its components, including end-expiratory lung volume, have not been carefully studied. We measured pulmonary conductance for gas exchange based on lung diffusion for carbon monoxide in patients receiving pressure-support ventilation. Design:Prospective, randomized, crossover study. Setting:Medical intensive care unit of a university hospital. Patients:Sixteen patients mechanically ventilated in pressure-support ventilation mode and free from chronic obstructive pulmonary disease. Interventions:Two pressure-support ventilation levels (5 cm H2O difference) at the same level of positive end-expiratory pressure. Measurements and Main Results:End-expiratory lung volume, lung diffusion for carbon monoxide, and SpO2/Fio2 were evaluated. Increasing pressure-support ventilation by 5 cm H2O significantly increased the mean tidal volume from 6.8 to 8.5 mL/kg of predicted body weight and decreased the mean respiratory rate by 6.6 breaths per minute. Although SpO2/Fio2 did not change significantly, there was a slight but significant decrease in lung diffusion for carbon monoxide (average decay rate of 4.5%) at high pressure-support ventilation. The pressure-support ventilation level did not significantly affect end-expiratory lung volume (1737 ± 629 mL at 9.6 ± 2.5 cm H2O pressure-support ventilation level vs. 1749 ± 657 mL at 14.9 ± 2.1 cm H2O pressure-support ventilation level). Conclusions:A 5-cm H2O increase in pressure-support ventilation neither affected end-expiratory lung volume nor increased the pulmonary volume participating in gas exchange. A target tidal volume closer to 6 mL/kg of predicted body weight than to 8 mL/kg during pressure-support ventilation was associated with better gas exchange.

Prognostic Value of Relative Adrenal Insufficiency During Cardiogenic Shock: A Prospective Cohort Study with Long-Term Follow-Up.

Background: Relative adrenal insufficiency (RAI) is common in intensive care unit patients, particularly during septic shock (SS). Cardiogenic shock (CS) may share some pathophysiological features with SS. The aim of this study was to evaluate the prevalence and long-term prognosis of RAI during CS. Patients and Methods: Prospective observational study conducted in the intensive care and cardiology units in one university hospital in France. Patients meeting the criteria for CS without prior corticosteroid therapy were included. Total blood cortisol levels were assessed immediately before (T0) a short corticotropin stimulation test (0.25 mg i.v. of tetracosactrin) and 30 and 60 min afterward. &Dgr;max was defined as the difference between the maximal value after the test and T0. Results: Of the 92 patients enrolled, 42 (46%) (95% confidence interval [CI] [36%–56%]) died in hospital and 7 more died during a median follow-up of 616 [57–2,498] days, for an overall mortality rate of 53% (95% CI [43%–63%]). Three groups were identified based on the corticotropin test: group 1 (T0 ⩽798 nmol/L and &Dgr;max >473 nmol/L), group 2 ([T0 >798 nmol/L and &Dgr;max >473 nmol/L] or [T0 ⩽798 nmol/L and &Dgr;max ⩽473 nmol/L]), and group 3 (T0 >798 nmol/L and &Dgr;max ⩽473 nmol/L) with an overall survival of 76%, 43%, and 15%, respectively (log rank P = 0.003). In the multivariable analysis, adrenal nonresponse (group 3) was an independent predictor of mortality (P = 0.04), along with left ventricular ejection fraction, Simplified Acute Physiology Score II, and cardiac arrest. Conclusions: These data suggest that a short corticotropin test has a good prognostic value in CS and allows identifying patients at higher risk of death.

Neuroimaging findings of postnatally acquired Zika virus infection: a pictorial essay

Zika virus (ZIKV) is a mosquito-borne arbovirus from the Flaviviridae family, first discovered in 1947. There has been no report of severe complications caused by this virus in humans until recently. However, it is confirmed now that prenatally acquired ZIKV infection may cause severe congenital brain abnormalities in the infected fetuses. In addition, there has been an increasing number of reports during recent years about the causal relationship between postnatally acquired ZIKV infection and severe neurologic complications (mostly immune-mediated ones). Hence, ZIKV should not be considered as benign as it was initially thought, but it might be seen as a serious global threat to human health that may severely affect not only fetuses. In this pictorial essay, we aim to describe and illustrate the currently recognized spectrum of neuroimaging findings in postnatally acquired ZIKV infection. Although neurologic complications do not frequently occur in postnatal ZIKV infection, it is important to be aware of them because they may cause high morbidity and mortality in the affected patients. In addition to clinical and laboratory findings, neuroimaging may help in the diagnostic work-up to make the correct diagnosis, determine the extent of the disease, and follow the clinical course.

Pulmonary Vascular Dysfunction and Cor Pulmonale During Acute Respiratory Distress Syndrome in Sicklers.

Background: Acute chest syndrome (ACS) is the most common cause of death among sickle cell disease (SCD) adult patients. Pulmonary vascular dysfunction (PVD) and acute cor pulmonale (ACP) are common during acute respiratory distress syndrome (ARDS) and their prevalence may be even more important during ARDS related to ACS (ACS-ARDS). The objective of this study was to evaluate the prevalence and prognosis of PVD and ACP during ACS-ARDS. Patients and Methods: This was a retrospective analysis over a 10-year period of patients with moderate-to-severe ARDS. PVD and ACP were assessed by echocardiography. ARDS episodes were assigned to ACS-ARDS or nonACS-ARDS group according to whether the clinical insult was ACS or not, respectively. To evaluate independent factors associated with ACP, significant univariable risk factors were examined using logistic regression and propensity score analyses. Results: A total of 362 patients were analyzed, including 24 ACS-ARDS. PVD and ACP were identified, respectively, in 24 (100%) and 20 (83%) ACS-ARDS patients, as compared with 204 (60%) and 68 (20%) nonACS-ARDS patients (P < 0.0001). The mortality did not differ between ACS-ARDS and nonACS-ARDS patients. Both the crude (odds ratio [OR], 19.9; 95% confidence interval [CI], 6.6–60; P < 0.0001), multivariable adjustment (OR, 27.4; 95% CI, 8.2–91.5; P < 0.001), and propensity-matched (OR, 11.7; 95% CI, 1.2–110.8; P = 0.03) analyses found a significant association between ACS-ARDS and ACP. Conclusions: All SCD patients presenting with moderate-to-severe ARDS as a consequence of ACS experienced PVD and more than 80% of them exhibited ACP. These results suggest a predominant role for PVD in the pathogenesis of severe forms of ACS.