Giorgio Conti

A multiple-center survey on the use in clinical practice of noninvasive ventilation as a first-line intervention for acute respiratory distress syndrome

Objective: In randomized studies of heterogeneous patients with hypoxemic acute respiratory failure, noninvasive positive pressure ventilation (NPPV) was associated with a significant reduction in endotracheal intubation. The role of NPPV in patients with acute respiratory distress syndrome (ARDS) is still unclear. The objective was to investigate the application of NPPV as a first‐line intervention in patients with early ARDS, describing what happens in everyday clinical practice in centers having expertise with NPPV. Design: Prospective, multiple‐center cohort study. Setting: Three European intensive care units having expertise with NPPV. Patients: Between March 2002 and April 2004, 479 patients with ARDS were admitted to the intensive care units. Three hundred and thirty‐two ARDS patients were already intubated, so 147 were eligible for the study. Interventions: Application of NPPV. Measurements and Main Results: NPPV improved gas exchange and avoided intubation in 79 patients (54%). Avoidance of intubation was associated with less ventilator‐associated pneumonia (2% vs. 20%; p < .001) and a lower intensive care unit mortality rate (6% vs. 53%; p < .001). Intubation was more likely in patients who were older (p = .02), had a higher Simplified Acute Physiology Score (SAPS) II (p < .001), or needed a higher level of positive end‐expiratory pressure (p = .03) and pressure support ventilation (p = .02). Only SAPS II >34 and a Pao2/Fio2 ≤175 after 1 hr of NPPV were independently associated with NPPV failure and need for endotracheal intubation. Conclusions: In expert centers, NPPV applied as first‐line intervention in ARDS avoided intubation in 54% of treated patients. A SAPS II >34 and the inability to improve Pao2/Fio2 after 1 hr of NPPV were predictors of failure.

Noninvasive vs. conventional mechanical ventilation in patients with chronic obstructive pulmonary disease after failure of medical treatment in the ward: a randomized trial

Abstract Objective. We conducted a randomized prospective study comparing noninvasive positive pressure ventilation (NPPV) with conventional mechanical ventilation via endotracheal intubation (ETI) in a group of patients with chronic obstructive pulmonary disease who failed standard medical treatment in the emergency ward after initial improvement and met predetermined criteria for ventilatory support. Design and setting. Prospective randomized study in a university hospital 13-bed general ICU. Patients. Forty-nine patients were randomly assigned to receive NPPV (n=23) or conventional ventilation (n=26). Results. both NPPV and conventional ventilation significantly improved gas exchanges. The two groups had similar length of ICU stay, number of days on mechanical ventilation, overall complications, ICU mortality, and hospital mortality. In the NPPV group 11 (48%) patients avoided intubation, survived, and had a shorter duration of ICU stay than intubated patients. One year following hospital discharge the NPPV group had fewer patients readmitted to the hospital (65% vs. 100%) or requiring de novo permanent oxygen supplementation (0% vs. 36%). Conclusions. The use of NPPV in patients with chronic obstructive pulmonary disease and acute respiratory failure requiring ventilatory support after failure of medical treatment avoided ETI in 48% of the patients, had the same ICU mortality as conventional treatment and, at 1-year follow-up was associated with fewer patients readmitted to the hospital or requiring for long-term oxygen supplementation. An editorial regarding this article can be found in the same issue (http://dx.doi.org/10.1007/s00134-002-1503-3).

A Comparison of Noninvasive Positive-Pressure Ventilation and Conventional Mechanical Ventilation in Patients with Acute Respiratory Failure

BACKGROUND AND METHODS The role of noninvasive positive-pressure ventilation delivered through a face mask in patients with acute respiratory failure is uncertain. We conducted a prospective, randomized trial of noninvasive positive-pressure ventilation as compared with endotracheal intubation with conventional mechanical ventilation in 64 patients with hypoxemic acute respiratory failure who required mechanical ventilation. RESULTS Within the first hour of ventilation, 20 of 32 patients (62 percent) in the noninvasive-ventilation group and 15 of 32 (47 percent) in the conventional-ventilation group had an improved ratio of the partial pressure of arterial oxygen to the fraction of inspired oxygen (PaO2:FiO2) (P=0.21). Ten patients in the noninvasive-ventilation group subsequently required endotracheal intubation. Seventeen patients in the conventional-ventilation group (53 percent) and 23 in the noninvasive-ventilation group (72 percent) survived their stay in the intensive care unit (odds ratio, 0.4; 95 percent confidence interval, 0.1 to 1.4; P=0.19); 16 patients in the conventional-ventilation group and 22 patients in the noninvasive-ventilation group were discharged from the hospital. More patients in the conventional-ventilation group had serious complications (66 percent vs. 38 percent, P=0.02) and had pneumonia or sinusitis related to the endotracheal tube (31 percent vs. 3 percent, P=0.003). Among the survivors, patients in the noninvasive-ventilation group had shorter periods of ventilation (P=0.006) and shorter stays in the intensive care unit (P=0.002). CONCLUSIONS In patients with acute respiratory failure, noninvasive ventilation was as effective as conventional ventilation in improving gas exchange and was associated with fewer serious complications and shorter stays in the intensive care unit.

New treatment of acute hypoxemic respiratory failure: Noninvasive pressure support ventilation delivered by helmet: A pilot controlled trial

OBJECTIVE To assess the efficacy of noninvasive pressure support ventilation (NPSV) using a new special helmet as first-line intervention to treat patients with hypoxemic acute respiratory failure (ARF), in comparison to NPSV using standard facial mask. DESIGN AND SETTING Prospective clinical pilot investigation with matched control group in three intensive care units of university hospitals. PATIENTS AND METHODS Thirty-three consecutive patients without chronic obstructive pulmonary disease and with hypoxemic ARF (defined as severe dyspnea at rest, respiratory rate >30 breaths/min, PaO2:FiO2 < 200, and active contraction of the accessory muscles of respiration) were enrolled. Each patient treated with NPSV by helmet was matched with two controls with ARF treated with NPSV via a facial mask, selected by simplified acute physiologic score II, age, PaO2/FiO2, and arterial pH at admission. Primary end points were the improvement of gas exchanges, the need for endotracheal intubation, and the complications related to NPSV. RESULTS The 33 patients and the 66 controls had similar characteristics at baseline. Both groups improved oxygenation after NPSV. Eight patients (24%) in the helmet group and 21 patients (32%) in the facial mask group (p = .3) failed NPSV and were intubated. No patients failed NPSV because of intolerance of the technique in the helmet group in comparison with 8 patients (38%) in the mask group (p = .047). Complications related to the technique (skin necrosis, gastric distension, and eye irritation) were fewer in the helmet group compared with the mask group (no patients vs. 14 patients (21%), p = .002). The helmet allowed the continuous application of NPSV for a longer period of time (p = .05). Length of stay in the intensive care unit, intensive care, and hospital mortality were not different. CONCLUSIONS NPSV by helmet successfully treated hypoxemic ARF, with better tolerance and fewer complications than facial mask NPSV.

Intrinsic positive end-expiratory pressure (PEEPi)

Positive end-expiratory pressure (PEEP) is one of the most frequently discussed topics in critical care medicine. However, alveolar pressure can remain positive throughout expiration without PEEP set by the ventilator whenever the time available to breathe out is shorter than the time required to decompress the lungs to the elastic equilibrium volume of the total respiratory system (Vr). The end-expiratory elastic recoil (Pel,rs) due to incomplete expiration has been termed auto PEEP, occult PEEP [1], inadvertent PEEP [2], endogenous PEEP, internal PEEP and intrinsic PEEP [3, 4] owing to its similarity and contrast with PEEP set by the ventilator. The purpose of this article is to provide a comprehensive review of the studies on this interesting aspect of critical care medicine, from the underlying physiological mechanism(s) to the clinical and therapeutic implications, through measurement and monitoring in the intensive care setting.

Noninvasive positive pressure ventilation using a helmet in patients with acute exacerbation of chronic obstructive pulmonary disease : a feasibility study

BackgroundNoninvasive positive pressure ventilation (NPPV) with a facemask (FM) is effective in patients with acute exacerbation of their chronic obstructive pulmonary disease. Whether it is feasible to treat these patients with NPPV delivered by a helmet is not known. MethodsOver a 4-month period, the authors studied 33 chronic obstructive pulmonary disease patients with acute exacerbation who were admitted to four intensive care units and treated with helmet NPPV. The patients were compared with 33 historical controls treated with FM NPPV, matched for simplified acute physiologic score (SAPS II), age, Paco2, pH, and Pao2:fractional inspired oxygen tension. The primary endpoints were the feasibility of the technique, improvement of gas exchange, and need for intubation. ResultsThe baseline characteristics of the two groups were similar. Ten patients in the helmet group and 14 in the FM group (P = 0.22) were intubated. In the helmet group, no patients were unable to tolerate NPPV, whereas five patients required intubation in the FM group (P = 0.047). After 1 h of treatment, both groups had a significant reduction of Paco2 with improvement of pH; Paco2 decreased less in the helmet group (P = 0.01). On discontinuing support, Paco2 was higher (P = 0.002) and pH lower (P = 0.02) in the helmet group than in the control group. One patient in the helmet group, and 12 in the FM group, developed complications related to NPPV (P < 0.001). Length of intensive care unit stay, intensive care unit, and hospital mortality were similar in both groups. ConclusionsHelmet NPPV is feasible and can be used to treat chronic obstructive pulmonary disease patients with acute exacerbation, but it does not improve carbon dioxide elimination as efficiently as does FM NPPV.

Effects of levosimendan on right ventricular afterload in patients with acute respiratory distress syndrome: a pilot study.

Objective:Acute respiratory distress syndrome (ARDS) is frequently associated with increased pulmonary vascular resistance and thus with systolic load of the right ventricle. We hypothesized that levosimendan, a new calcium sensitizer with potential pulmonary vasodilator properties, improves hemodynamics by unloading the right ventricle in patients with ARDS. Design:Prospective, randomized, placebo-controlled, pilot study. Setting:Twenty-two-bed multidisciplinary intensive care unit of a university hospital. Patients:Thirty-five patients with ARDS in association with septic shock. Interventions:Patients were randomly allocated to receive a 24-hr infusion of either levosimendan 0.2 &mgr;g/kg/min (n = 18) or placebo (n = 17). Data from right heart catheterization, cardiac magnetic resonance, arterial and mixed venous oxygen tensions and saturations, and carbon dioxide tensions were obtained before and 24 hrs after drug infusion. Measurements and Main Results:At a mean arterial pressure between 70 and 80 mm Hg (sustained with norepinephrine infusion), levosimendan increased cardiac index (from 3.8 ± 1.1 to 4.2 ± 1.0 L/min/m2) and decreased mean pulmonary artery pressure (from 29 ± 3 to 25 ± 3 mm Hg) and pulmonary vascular resistance index (from 290 ± 77 to 213 ± 50 dynes/s/cm5/m2; each p < .05). Levosimendan also decreased right ventricular end-systolic volume and increased right ventricular ejection fraction (p < .05). In addition, levosimendan increased mixed venous oxygen saturation (from 63 ± 8 to 70 ± 8%; p < .01). Conclusions:This study provides evidence that levosimendan improves right ventricular performance through pulmonary vasodilator effects in septic patients with ARDS. A large multiple-center trial is needed to investigate whether levosimendan is able to improve the overall prognosis of patients with sepsis and ARDS.

Noninvasive versus invasive ventilation for acute respiratory failure in patients with hematologic malignancies: A 5-year multicenter observational survey

Background:Mortality is high among patients with hematologic malignancies admitted to intensive care units for acute respiratory failure. Early noninvasive mechanical ventilation seems to improve outcomes. Objective:To characterize noninvasive mechanical ventilation use in Italian intensive care units for acute respiratory failure patients with hematologic malignancies and its impact on outcomes vs. invasive mechanical ventilation. Design, Setting, Participants:Retrospective analysis of observational data prospectively collected in 2002–2006 on 1,302 patients with hematologic malignancies admitted with acute respiratory failure to 158 Italian intensive care units. Measurements:Mortality (intensive care unit and hospital) was assessed in patients treated initially with noninvasive mechanical ventilation vs. invasive mechanical ventilation and in those treated with invasive mechanical ventilation ab initio vs. after noninvasive mechanical ventilation failure. Findings were adjusted for propensity scores reflecting the probability of initial treatment with noninvasive mechanical ventilation. Results:Few patients (21%) initially received noninvasive mechanical ventilation; 46% of these later required invasive mechanical ventilation. Better outcomes were associated with successful noninvasive mechanical ventilation (vs. invasive mechanical ventilation ab initio and vs. invasive mechanical ventilation after noninvasive mechanical ventilation failure), particularly in patients with acute lung injury/adult respiratory distress syndrome (mortality: 42% vs. 69% and 77%, respectively). Delayed vs. immediate invasive mechanical ventilation was associated with slightly but not significantly higher hospital mortality (65% vs. 58%, p = .12). After propensity-score adjustment, noninvasive mechanical ventilation was associated with significantly lower mortality than invasive mechanical ventilation. Limitations:The population could not be stratified according to specific hematologic diagnoses. Furthermore, the study was observational, and treatment groups may have included unaccounted for differences in covariates although the risk of this bias was minimized with propensity score regression adjustment. Conclusions:In patients with hematologic malignancies, acute respiratory failure should probably be managed initially with noninvasive mechanical ventilation. Further study is needed to determine whether immediate invasive mechanical ventilation might offer some benefits for those with acute lung injury/adult respiratory distress syndrome.

Noninvasive mechanical ventilation as a palliative treatment of acute respiratory failure in patients with end-stage solid cancer

Noninvasive ventilation (NIV) is widely used in the treatment of acute respiratory failure (ARF), but not in patients with end-stage solid cancer in whom any form of mechanical ventilation tends to be avoided. In a prospective study, we investigated the use of NIV in 23 patients with solid malignancies receiving palliative care and who were affected by severe hypoxic or hypercapnic ARF. The most frequent causes of ARF were exacerbations of preexisting pulmonary diseases and pneumonia. After one hour, NIV significantly improved PaO2/FiO2 (from 154±48 to 187±55) and the Borg dyspnoea score (from 5.59±1.2 to 2.3±0.3). NIV also improved pH, but only in the subset of hypercapnic patients. Thirteen of 23 (57%) patients were successfully ventilated and discharged alive, while 10/23 patients (43%) met the criteria for intubation or died after an initial trial of NIV. Only two of these patients accepted invasive ventilation. The mortality rate in this subgroup was 9/10 (90%). A higher Simplified Acute Physiology Score (SAPS II) and a lower PaO2/FiO2 on admission were associated with a lower probability of survival. Patients with ARF and end-stage solid malignancies have an overall ICU and 1-year mortality rate of 39% and 87%, respectively, but despite this, a consistent subset of patients may still be successfully treated with NIV, if the cause of ARF is reversible.

Prophylactic fenoldopam for renal protection in sepsis: a randomized, double-blind, placebo-controlled pilot trial.

Objective:Acute renal failure is common in septic patients. Fenoldopam, a dopamine-1 receptor agonist, increases renal blood flow and may, therefore, reduce the risk of acute renal failure in such patients. Accordingly, we sought to determine the safety and efficacy of fenoldopam for the prevention of acute renal failure in septic patients. Design:Prospective, double-blind, placebo-controlled trial. Setting:Three multidisciplinary intensive care units at a university hospital. Patients:Three hundred septic patients with baseline serum creatinine concentrations <150 &mgr;mol/L. Interventions:We randomized patients to a continuous infusion of either fenoldopam (n = 150) at 0.09 &mgr;g·kg−1·min−1 or placebo (n = 150) while in the intensive care unit. The primary outcome measure was the incidence of acute renal failure, defined as a serum creatinine concentration increase to >150 &mgr;mol/L, during study drug infusion. Measurements and main results:The incidence of acute renal failure was significantly lower in the fenoldopam group compared with the control group (29 vs. 51 patients; p = .006). The odds ratio of developing acute renal failure for patients treated with fenoldopam was estimated to be 0.47 (p = .005). The difference in the incidence of severe acute renal failure (creatinine >300 &mgr;mol/L), however, failed to achieve statistical significance (10 vs. 21; p = .056). The length of intensive care unit stay in surviving patients was significantly lower in the fenoldopam group compared with the control group (10.64 ± 9.3 vs. 13.4 ± 14.0; p < .001). There were no complications of fenoldopam infusion. A direct effect of treatment on the probability of death, beyond its effect on acute renal failure, was not significant (odds ratio = 0.68, p = .1). Conclusions:Compared with placebo, low-dose fenoldopam resulted in a smaller increase in serum creatinine in septic patients. The clinical significance of this finding is uncertain. A large multiple-center trial is now needed to confirm these findings.