Frédéric Vargas

Noninvasive Ventilation in Immunosuppressed Patients with Pulmonary Infiltrates, Fever, and Acute Respiratory Failure

BACKGROUND Avoiding intubation is a major goal in the management of respiratory failure, particularly in immunosuppressed patients. Nevertheless, there are only limited data on the efficacy of noninvasive ventilation in these high-risk patients. METHODS We conducted a prospective, randomized trial of intermittent noninvasive ventilation, as compared with standard treatment with supplemental oxygen and no ventilatory support, in 52 immunosuppressed patients with pulmonary infiltrates, fever, and an early stage of hypoxemic acute respiratory failure. Periods of noninvasive ventilation delivered through a face mask were alternated every three hours with periods of spontaneous breathing with supplemental oxygen. The ventilation periods lasted at least 45 minutes. Decisions to intubate were made according to standard, predetermined criteria. RESULTS The base-line characteristics of the two groups were similar; each group of 26 patients included 15 patients with hematologic cancer and neutropenia. Fewer patients in the noninvasive-ventilation group than in the standard-treatment group required endotracheal intubation (12 vs. 20, P=0.03), had serious complications (13 vs. 21, P=0.02), died in the intensive care unit (10 vs. 18, P=0.03), or died in the hospital (13 vs. 21, P=0.02). CONCLUSIONS In selected immunosuppressed patients with pneumonitis and acute respiratory failure, early initiation of noninvasive ventilation is associated with significant reductions in the rates of endotracheal intubation and serious complications and an improved likelihood of survival to hospital discharge.

Strategy of antibiotic rotation: long-term effect on incidence and susceptibilities of Gram-negative bacilli responsible for ventilator-associated pneumonia.

ObjectiveTo evaluate the long-term effect of a program of rotating antibiotics on the incidence of ventilator-associated pneumonia and the susceptibilities of Gram-negative bacilli responsible for ventilator-associated pneumonia. DesignProspective program for the surveillance of antibiotic susceptibilities of microorganisms responsible for ventilator-associated pneumonia. SettingAcademic, university-based, medical intensive care unit (16 beds). Subjects2,856 mechanically ventilated patients. InterventionsA new program of antibiotic use was introduced at the end of 1996 that involved the rotation of antibiotics in empirical and therapeutic use of the treatment of ventilator-associated pneumonia. The rotation concerned the &bgr;-lactam and aminoglycoside classes, with a rotation interval of 1 month. The use of antibiotics was monitored monthly. No preference was given to any particular antibiotic. In a previous study, the period before the introduction of this protocol (1995–1996) was compared with the period 2 yrs after (1997–1998): The results indicated a decreased incidence of ventilator-associated pneumonia, a lower incidence of potentially resistant Gram-negative bacilli, and increased sensitivities of Gram-negative bacilli, especially Pseudomonas aeruginosa and Burkholderia cepacia. After 1998, we decided to continue a routine for this rotation. The long-term effect of this program was studied by comparing the incidence of Gram-negative bacilli responsible for ventilator-associated pneumonia and their susceptibilities obtained in a third period: 1999–2001. The long-term effect (5 yrs) of such a strategy—2-yr protocol period (1997–1998) and 3-yr routine period (1999–2001)—could be evaluated. Measurements and Main ResultsDuring the 7-yr study period, 2,856 patients were mechanically ventilated for >48 hrs. The incidence of ventilator-associated pneumonia remained significantly lower in period 3 (1999–2001): 23% (period 1, 1995–1996) vs. 15.7% (period 2, 1997–1998) vs. 16.3% (period 3, 1999–2001; p = .002). Late-onset ventilator-associated pneumonia occurred in 86.6% and 94% of cases, respectively, in periods 1 and 3 (p = .02). The decrease of the incidence of early-onset ventilator-associated pneumonia was statistically significant during the 7-yr study period: 13% vs. 9% vs. 5.9% (p = .02). Combined with a higher incidence of late-onset ventilator-associated pneumonia, the incidence of potentially resistant Gram-negative bacilli increased in period 3: 42.2% vs. 34.5% vs. 41.7% (nonsignificant), except for B. cepacia: 11.7% vs. 7.4% vs. 3.7% (p = .005). Nevertheless, the potential antibiotic-resistant Gram-negative bacilli were more sensitive to most of the &bgr;-lactams, especially piperacillin-tazobactam and cefepime. ConclusionsRotation of antibiotics could help to avoid ventilator-associated pneumonia. It could greatly improve the susceptibilities of the potentially antibiotic-resistant Gram-negative bacilli responsible for late-onset ventilator-associated pneumonia. This program could be applied in routine with good results 5 yrs after its introduction. Further studies, especially multiple-center trials, are necessary to confirm this result and better define the rotation type and intervals.

Noninvasive continuous positive airway pressure in neutropenic patients with acute respiratory failure requiring intensive care unit admission.

ObjectiveTo evaluate the tolerance and the efficacy of noninvasive continuous positive airway pressure (CPAP) in severe acute respiratory failure occurring in intensive care unit (ICU) neutropenic patients with hematologic malignancies, and to establish predictive variables of efficacy of this method. DesignProspective study over a 5-yr period. SettingHematologic and medical intensive care unit of a teaching hospital. MethodsAmong 129 neutropenic patients admitted to the ICU, 64 patients presented with febrile acute hypoxemic normocapnic respiratory failure (Pao2/Fio2 ratio <200) and were enrolled. In addition to standard therapy, patients received CPAP with a facial mask. The initial settings of the CPAP were 6 cm H2O positive end-expiratory pressure and Fio2 0.8 (80%). Physiologic measurements were performed at the end of 45 mins of ventilation with first adjustments. CPAP was used with a sequential mode (45 mins/3 hrs). CPAP was efficient if intubation was avoided. ResultsThe setting of CPAP, after adjustments, was as follows: positive end-expiratory pressure 7 ± 1 cm H2O and Fio2 0.7 ± 0.1 (70% ± 10%). For the 64 patients, CPAP was administered for a total of 6 ± 2 hrs during the first 24 hrs. The mean duration of CPAP was 7 ± 3 days. A reduction in respiratory rate to less than 25 breaths/min was achieved in 53% of patients. Pao2/Fio2 ratio increased from 128 ± 32 to 218 ± 28. CPAP was successful in avoiding endotracheal intubation in 16/64 patients. A total of 16 responders and four nonresponders survived. Hepatic failure was a criterion indicating the failure of CPAP1/16 vs. 26/48 (p = .001). In multivariate analysis, two variables were predictive of failure of CPAPSimplified Acute Physiology Score II (58 ± 14 vs. 41 ± 11) and a hepatic failure at the entry into the study. ConclusionCPAP was efficient in 25% of cases. All the responders survived. This noninvasive method was used as a way to avoid mechanical ventilation, which is well correlated with a poor prognosis in neutropenic ICU patients. Further controlled studies are needed to confirm the efficacy of noninvasive CPAP and to evaluate the most appropriate selection of immunocompromised patients.

Utility of fiberoptic bronchoscopy in neutropenic patients admitted to the intensive care unit with pulmonary infiltrates.

Objective To analyze the impact of fiberoptic bronchoscopy and bronchoalveolar lavage (BAL) on guiding the treatment and intensive care unit (ICU) clinical outcome in neutropenic patients with pulmonary infiltrates admitted to the ICU. Design Prospective collection of data. Setting Medical ICU in a teaching hospital. Patients During a 6-yr period, we analyzed the results of 93 fiberoptic bronchoscopies plus BALs performed in 93 consecutive neutropenic ICU patients. We separated the patients into two groups according to the cause of neutropenia (high-dose chemotherapy [n = 41] or stem cell transplantation [SCT; n = 52]). Results Of the 93 BALs, 53 were performed to evaluate diffuse infiltrates and 42 were performed on mechanically ventilated patients. Forty-nine percent of BALs (46 patients) were diagnostic, with a significantly better yield in ICU patients with high-dose chemotherapy-induced neutropenia (26 of 41 BALs). The number of cases of proven infectious pneumonia was significantly higher in this group of ICU neutropenic patients. In patients who underwent SCT, diffuse infiltrates were statistically correlated with a negative result of BAL. Twenty-six patients who underwent diagnostic BALs changed therapy. Sixteen complications (17%) occurred with only two intubations. The overall mortality rate in the ICU and the mortality rate in mechanically ventilated neutropenic patients were 71% and 93%, respectively. In neutropenic patients who underwent SCT, the mortality rate was statistically higher in patients in whom no diagnosis was established. Patients who had a diagnostic BAL that changed therapy did not have an increased probability of survival compared with patients who had a BAL that did not change therapy. Conclusions The use of routine diagnostic BAL in ICU neutropenic patients with pulmonary infiltrates is difficult to establish, even if BAL is helpful in the management of these critically ill patients. BAL in our ICU neutropenic patient population had an acceptable overall diagnostic yield (49%), which was higher in ICU patients with chemotherapy-induced neutropenia. Nevertheless, in the ICU, if BAL had a low complication rate, it had infrequently led to changed treatment and was not associated with improved patient survival.

Intrapulmonary percussive ventilation in acute exacerbations of COPD patients with mild respiratory acidosis: a randomized controlled trial [ISRCTN17802078]

IntroductionWe hypothesized that the use of intrapulmonary percussive ventilation (IPV), a technique designed to improve mucus clearance, could prove effective in avoiding further deterioration in patients with acute exacerbations of chronic obstructive pulmonary disease (COPD) with mild respiratory acidosis.MethodsThe study was performed in a medical intensive care unit of a university hospital. Thirty-three patients with exacerbations of COPD with a respiratory frequency ≥ 25/min, a PaCO2 > 45 Torr and 7.35 ≤ pH ≤ 7.38 were included in the study. Patients were randomly assigned to receive either standard treatment (control group) or standard treatment plus IPV (IPV group). The IPV group underwent two daily sessions of 30 minutes performed by a chest physiotherapist through a full face mask. The therapy was considered successful when both worsening of the exacerbation and a decrease in pH to under 7.35, which would have required non-invasive ventilation, were avoided.ResultsThirty minutes of IPV led to a significant decrease in respiratory rate, an increase in PaO2 and a decrease in PaCO2 (p < 0.05). Exacerbation worsened in 6 out of 17 patients in the control group versus 0 out of 16 in the IPV group (p < 0.05). The hospital stay was significantly shorter in the IPV group than in the control group (6.8 ± 1.0 vs. 7.9 ± 1.3 days, p < 0.05).ConclusionIPV is a safe technique and may prevent further deterioration in patients with acute exacerbations of COPD with mild respiratory acidosis.

Helmet with specific settings versus facemask for noninvasive ventilation.

Objective:To compare the physiologic effects of noninvasive pressure-support ventilation (NPSV) delivered by a facemask, a helmet with the same settings, and a helmet with specific settings. Inspiratory muscle effort, gas exchange, patient-ventilator synchrony, and comfort were evaluated. Design:Prospective crossover study. Setting:A 13-bed medical intensive care unit in a university hospital. Patients:Eleven patients at risk for respiratory distress requiring early NPSV after extubation. Intervention:One hour after extubation, three 20-minute NPSV periods were delivered in a random order by facemask, helmet, and helmet with 50% increases in both pressure support and positive end-expiratory pressure and with the highest pressurization rate (95% max). Measurements and Main Results:Flow and airway, esophageal, and gastric pressure signals were measured under the three NPSV conditions and during spontaneous breathing. Compared with the facemask, the helmet with the same settings resulted in a greater inspiratory muscle effort, but this difference was abolished by the specific settings (pressure-time product in cm H2O·s·min−1, 63.8 [27.3–85.9], 81.8 [36.0–111.5], and 58.0 [25.4–79.5], respectively, p < 0.05, compared with 209.3 [29.8–239.6] during spontaneous breathing). Compared with the facemask, the helmet with the same settings worsened patient-ventilator synchrony, as indicated by longer triggering-on and cycling-off delays (0.14 [0.11–0.20] seconds vs. 0.32 [0.26–0.43] seconds, p < 0.05; and 0.20 [0.08–0.24] seconds vs. 0.27 [0.25–0.35] seconds, p < 0.01, respectively). The specific settings significantly improved the triggering-on delay compared with the helmet without specific settings (p < 0.01). Tolerance was the same with the three methods. Conclusions:Our results suggest that increasing both the pressure-support level and positive end-expiratory pressure and using the highest pressurization rate may be advisable when providing NPSV via a helmet.

Bronchoscopy with bronchoalveolar lavage via the laryngeal mask airway in high-risk hypoxemic immunosuppressed patients.

ObjectiveFiberoptic bronchoscopy (FOB) and bronchoalveolar lavage (BAL) are major tools in the diagnosis of pulmonary complications in immunocompromised patients. Nevertheless, severe hypoxemia is an accepted contraindication to FOB in nonintubated patients. The purpose of this study was to evaluate the feasibility and safety of laryngeal mask airway (LMA)-supported FOB with BAL in immunosuppressed patients with suspected pneumonia and severe hypoxemia. DesignProspective, clinical investigation. SettingMedical intensive care unit of a university hospital. PatientsForty-six immunosuppressed patients admitted to our intensive care unit with suspected pneumonia and Pao2/Fio2 ≤ 125. InterventionsAfter the administration of 0.3 mg·kg−1 of etomidate, the patients were ventilated manually while receiving 1.0 Fio2. After the administration of 2.5 mg·kg−1 of propofol, followed by an infusion of 9.1 ± 2.3 mg·kg−1·hr−1of propofol, the LMA (size 3 or 4) was placed and connected to a bag-valve unit to allow manual ventilation with 1.0 Fio2. The FOB was introduced through a T-adapter attached to the LMA, and BAL was carried out with 150 mL of sterile 0.9% saline solution by sequential instillation and aspiration of 50-mL aliquots. Measurements and Main Results Three patients developed transient laryngospasm during passage of the bronchoscope via the LMA, which resolved with deepening of anesthesia. Changes in mean blood pressure, heart rate, Pao2/Fio2, and Paco2 values induced by the procedure did not reach significance. Seven patients (15%) presented hypotension (mean blood pressure, <60 mm Hg) maintained for 120 ± 40 secs, which required plasma expanders in three cases. Oxygen desaturation to <90% occurred in six patients (13%) during BAL. Nevertheless, the lowest Sao2 during the procedure was significantly higher than the initial Sao2 (94% ± 4% vs. 90% ± 2%). No patient required tracheal intubation during the 8 hrs after the procedure. BAL had an overall diagnostic yield of 65%. Because of the results obtained by using the BAL analysis, treatment was modified in 33 (72%) cases. ConclusionApplication of the LMA appears to be a safe and effective alternative to intubation for accomplishing FOB with BAL in immunosuppressed patients with suspected pneumonia and severe hypoxemia.

Fulminant Guillain-Barré syndrome mimicking cerebral death: case report and literature review.

Abstract A 45-year-old woman was admitted to the intensive care unit (ICU) for respiratory arrest. One day prior to admission, she had been nauseated and in a state of total exhaustion. On the night of admission she was unresponsive and developed gasping respiration. The patient was comatose with absent brainstem reflexes and appeared brain dead. Blood chemistry findings and brain magnetic resonance imaging were normal. Electroencephalogram revealed an alpha rhythmical activity unresponsive to painful or visual stimuli. The cerebrospinal fluid showed an albuminocytological dissociation. Guillain-Barré syndrome (GBS) was suspected. The electrophysiological evaluation revealed an inexcitability of all nerves. The pathological findings of the sural nerve biopsy indicated an axonal degeneration secondary to severe demyelination. GBS can very rarely present with coma and absent brainstem reflexes. This case illustrates the importance of electrophysiological tests and laboratory and imaging studies in patients with suspected brain death where a cause is not clearly determined.

Comparison of B-mode ultrasound and computed tomography in the diagnosis of maxillary sinusitis in mechanically ventilated patients.

ObjectiveTo compare B-mode ultrasound with sinus computed tomograph (CT) scan in the diagnosis of sinusitis in intubated patients undergoing mechanical ventilation. DesignProspective, clinical investigation. SettingMedical intensive care unit of a university hospital. PatientsFifty patients undergoing intubation and mechanical ventilation more than 2 days, with a clinical suspicion of paranasal sinusitis with purulent nasal discharge. InterventionsOne hundred paranasal sinuses were examined. A paranasal CT scan and a B-mode ultrasound were performed the same day. Radiologic maxillary sinusitis (RMS) was defined as complete opacification of the sinus or as the presence of an air-fluid level. Absence of RMS was defined as normal sinus or as the presence of mucosal thickening. Important RMS was defined by total opacity or air-fluid level larger than half of the sinus area. Moderate RMS was defined by air-fluid level inferior than half of the sinus area. For ultrasonographic procedure, the image defined as normal was an acoustic shadow arising from the front wall. Two levels of positive echography were described: 1) a moderate lesion was defined as the visualization only of the hyperechogenic posterior wall of the sinus; 2) an important lesion was defined as the hyperechogenic visualization of posterior wall and the extension by the internal wall of the sinus outlining the hypoechogenic sinus cavity. Measurements and Main Results Sensibility, specificity, positive predictive value, and negative predictive value of B-mode ultrasound compared with CT were, respectively: 100% (95% confidence intervals [95% CI] = 94.9–100.0), 96.7% (95% CI = 82.8–99.9), 98.6% (95% CI = 92.4–99.9), and 100% (95% CI = 88.1–100). The concordance between a moderate B-mode ultrasound lesion and a moderate RMS on CT, and between an important B-mode ultrasound lesion and an important RMS on CT, assessed using kappa statistics was 93%. The concordance between B-mode ultrasound’s results and CT’s results assessed using weighted kappa statistics was 97%. ConclusionB-mode ultrasound may be proposed first-line in a ventilated patient with suspicion of maxillary sinusitis.

Prognostic impact of high-flow nasal cannula oxygen supply in an ICU patient with pulmonary fibrosis complicated by acute respiratory failure

Dear Editor, Pulmonary fibrosis (PF) complicated by acute respiratory failure (ARF) requiring ventilatory support has a poor prognosis, challenging the opportunity for intensive care unit (ICU) admission [1]. A new device called a high-flow nasal cannula (HFNC) is used increasingly in hypoxemic ARF [2]. We report the case of a patient who was admitted with PF-related ARF and received HFNC oxygen during his ICU stay. A 73-year-old man was admitted to the emergency department with subfebrile ARF in the context of chronic ischemic and valvular myocardiopathy treated routinely with trinitrine, spironolactone, bisoprolol and lisinopril. Amiodarone had been introduced 1 month previously. Oxygen therapy (10 l/min) with a reservoir mask was started, and transthoracic echocardiography rapidly eliminated a cardiac origin of the diffuse alveolo-interstitial infiltrate. Antibiotic treatment was introduced, but he was transferred to the ICU after deterioration of his respiratory status. His respiratory rate fluctuated between 25 and 30 breaths/min despite 15 l/min oxygen therapy. Arterial blood gas analysis revealed a PaO2 of 55 mmHg without respiratory acidosis. HFNC (OptiflowTM system; Fisher and Paykel Healthcare Ltd., Auckland, New Zealand) was introduced with an air/oxygen blender at 40 l/min and 80% FiO2. His PaO2 improved to 82 mmHg. Thoracic computed tomography revealed PF. The recent introduction of amiodarone was considered to be responsible for the PF as no other alternative etiology could be identified. As no improvement was observed after the introduction of 2 mg/kg corticosteroids on day 5 (D5), cyclophosphamide (600 mg/m) was administered on D12. The change in PaO2/FiO2 ratio over time is shown in Fig. 1. It was decided to withhold invasive ventilation on D22, and palliative care was initiated; HFNC oxygen was continued. Cyclophosphamide administration was repeated on D26. Ten days later, his PaO2/FiO2 ratio and radiographic infiltrates had improved so dramatically that the withhold order was cancelled (Fig. 1). HFNC oxygen was stopped. The patient was discharged from the ICU on D46 with 4 l/min nasal oxygen and returned home 2 weeks later. He died 3 months later with homebased palliative care. The prognosis of acute exacerbation of PF is extremely poor, particularly if ventilatory support is required (in-hospital mortality up to 87%) [1]. The few survivors all have a specific (diagnosis [3] or surgical procedure-related ARF [4]) or reversible cause [1]. In other cases, it has been suggested that mechanical ventilation is futile and that palliative care should be initiated promptly [1, 4]. Non-invasive means of providing oxygen can then be proposed until patients with potentially reversible causes of ARF are identified. We report the exceptional case of an elderly patient who improved only 1 month after ICU admission. Oxygen was first provided by noninvasive ventilation, but this was poorly tolerated [2] as was high oxygen supply with a reservoir mask. HFNC promotes comfort (in part by improving the heating and