Acidemia does not affect outcomes of patients with acute cardiogenic pulmonary edema treated with continuous positive airway pressure

Decompensated metabolic acidosis in the emergency department: Epidemiology, sodium bicarbonate therapy, and clinical outcomes

Objective

This article aims to describe the epidemiology of decompensated metabolic acidosis, the characteristics of sodium bicarbonate (SB) administration and outcomes in emergency department (ED) patients.

Design

This is a retrospective cohort study.

Setting

ED of a tertiary referral hospital in Melbourne, Australia.

Participants

Adult patients presenting to the ED between 1 July 2011 and 20 September 2020 with decompensated metabolic acidosis diagnosed on arterial blood gas (ABG).

Main outcome measures

We compared characteristics between those treated with or without SB. We studied SB administration characteristics, change in laboratory variables, factors associated with use and dose, and clinical outcomes.

Results

Among 753,613 ED patients, 314 had decompensated metabolic acidosis on ABG, with 17.8% receiving SB. Patients in the SB group had lower median pH, CO2, bicarbonate, and base excess (BE) levels compared with the No SB group (P < 0.01). The median number of SB doses in the SB group was one treatment. This was given at a median total dose of 100 mmol and at a median of 2.8 h after the diagnostic blood gas results. Only 42% of patients in the SB group had a subsequent blood gas measured. In such patients, there was no significant change in pH, bicarbonate, or BE. SB therapy was not independently associated with mortality.

Conclusions

ABG-confirmed decompensated metabolic acidosis was rare but associated with a high mortality. SB administration occurred in a minority of patients and in more acidaemic patients. However, SB dose was stereotypical and not tailored to acidosis severity. Assessment of SB effect was infrequent and showed no correction of acidosis. Systematic studies of titrated SB therapy are required to inform current practice.

Continuous positive airway pressure therapy in the management of hypercapnic cardiogenic pulmonary edema

Continuous positive airway pressure (CPAP) therapy or non-invasive ventilation (NIV) represent the first line therapy for acute cardiogenic pulmonary edema (CPE) together with medical therapy. CPAP benefits in acute CPE with normo-hypocapnia are known, but it is not clear whether the use of CPAP is safe in the hypercapnic patients. The aim of this study is to evaluate CPAP efficacy in the treatment of hypercapnic CPE. We enrolled 9 patients admitted to the emergency room with diagnosis of acute CPE based on history, clinical examination, arterial blood gas analysis (ABG) and lung-heart ultrasound examination. We selected patients with hypercapnia (pCO2 >50 mmHg) and bicarbonate levels <30 mEq/L. All patients received medical therapy with furosemide and nitrates and helmet CPAP therapy. All patients received a second and a third ABG, respectively at 30 and 60 min. Primary end-points of the study were respiratory distress resolution, pCO2 reduction, pH improvement, lactates normalization and the no need for non-invasive ventilation or endo-tracheal intubation. All patients showed resolution of respiratory distress with CPAP weaning and shift to Venturi mask with no need for NIV or endo-tracheal intubation. Serial ABG tests showed clear reduction in CO2 levels with improvement of pH and progressive lactate reduction. CPAP therapy can be effective in the treatment of hypercapnic CPE as long as the patients have no signs of chronic hypercapnia on ABG and as long as the diagnosis of heart failure is supported by bedside lung-heart ultrasound examination.

Validity of a clinical scale in predicting the failure of non-invasive ventilation in hypoxemic patients

INTRODUCTION

The HACOR scale is a clinical score that can predict early failure of NIV in hypoxemic acute respiratory failure (ARF) The aim of this study is to analyze the validity of the HACOR scale.

METHODS

A retrospective study of a cohort of over 2749 episodes on 2711 consecutive patients requiring NIV for hypoxemic ARF in a polyvalent intensive care unit. The scale was measured before starting NIV and at 1, 6, 12, 24 and 48 h after the initiation of NIV.

RESULTS

NIV failure occurred in 963 patients (35%). The value of the HACOR scale before NIV did not differ between success and failure. However, at 1, 6, 12, 24 and 48 h of NIV, the scale values clearly differed between the two groups. The HACOR scale at NIV initiation accurately predicts NIV failure in the first hour, with an optimal cut-off value of 8 points. The AUC for predicting NIV failure with HACOR at 1 h is greater than 0.9 in patients with pneumonia and adult respiratory distress syndrome (ARDS).

CONCLUSIONS

The HACOR scale measured at 1 h after NIV initiation accurately predicts NIV failure, especially in pneumonia and ARDS.

Non-Invasive Mechanical Ventilation Versus Continuous Positive Airway Pressure Relating to Cardiogenic Pulmonary Edema in an Intensive Care Unit

BACKGROUND

To compare the application of non-invasive ventilation (NIV) versus continuous positive airway pressure (CPAP) in the treatment of patients with cardiogenic pulmonary edema (CPE) admitted to an intensive care unit (ICU).

METHODS

In a prospective, randomized, controlled study performed in an ICU, patients with CPE were assigned to NIV (n=56) or CPAP (n=54). Primary outcome was intubation rate. Secondary outcomes included duration of ventilation, length of ICU and hospital stay, improvement of gas exchange, complications, ICU and hospital mortality, and 28-day mortality. The outcomes were analyzed in hypercapnic patients (PaCO₂>45mmHg) with no underlying chronic lung disease.

RESULTS

Both devices led to similar clinical and gas exchange improvement; however, in the first 60min of treatment a higher PaO₂/FiO₂ ratio was observed in the NIV group (205±112 in NIV vs. 150±84 in CPAP, P=.02). The rate of intubation was similar in both groups (9% in NIV vs. 9% in CPAP, P=1.0). There were no differences in duration of ventilation, ICU and length of hospital stay. There were no significant differences in ICU, hospital and 28-d mortality between groups. In the hypercapnic group, there were no differences between NIV and CPAP.

CONCLUSIONS

Either NIV or CPAP are recommended in patients with CPE in the ICU. Outcomes in the hypercapnic group with no chronic lung disease were similar using NIV or CPAP.

Risk factors for noninvasive ventilation failure in patients with acute cardiogenic pulmonary edema: A prospective, observational cohort study

PURPOSE

We identified risk factors for noninvasive ventilation (NIV) failure in patients with acute cardiogenic pulmonary edema (ACPE).

MATERIALS AND METHODS

We conducted an observational cohort study over a 3-year period in a 28-bed emergency intensive care unit (EICU) and prospectively included all consecutive patients in whom NIV was attempted as initial ventilatory support for ACPE. The primary outcome variables were NIV failure rate and risk factors for NIV failure.

RESULTS

Among the 118 patients in the study, NIV failed for 44 (37.3%) patients. Risk factors for NIV failure were Killip class IV (odds ratio [OR], 28.56; 95% confidence interval [CI], 2.17-375.73; p=0.011), left ventricular ejection fraction (LVEF) <30% (OR, 9.54; 95% CI, 1.01-90.55; p=0.050) and B-type natriuretic peptide (BNP) ≥3350pg/mL (OR, 39.63; 95% CI, 3.92-400.79; p=0.002) at baseline, and fluid balance ≥400mL within 24h after ACPE (OR, 13.19; 95% CI, 1.18-147.70; p=0.036).

CONCLUSIONS

NIV failure occurred in 37.3% of ACPE patients in a real-world EICU. When patients had Killip class IV, a lower LVEF, a higher BNP, and a more positive fluid balance within 24h after ACPE, the risk of failure was higher. TRIAL REGISTRATION CLINICALTRIALS.

GOV IDENTIFIER

NCT02653365.

The effect of CPAP treatment on venous lactate and arterial blood gas among obstructive sleep apnea syndrome patients

PURPOSE

The aim of this observational study was to investigate the influence of continuous positive airway pressure (CPAP) on arterial blood gas and venous lactate, markers of tissue hypoxia, among obstructive sleep apnea syndrome (OSAS) patients, and determine the risk factor of serum lactate and hydrogen ion concentration (PH) in OSAS patients.

MATERIALS AND METHODS

One-hundred and nine patients with newly diagnosed OSAS were enrolled in the study. All individuals were treated with CPAP for one night. Venous lactate and arterial blood gas were gathered from all subjects in the morning at the end of polysomnography and the next morning after CPAP treatment.

RESULTS

Of the 109 selected subjects, the average lactate level was 2.23 ± 0.59 mmol/L, and the mean PH, PaO₂, and PaCO₂ were 7.380 ± 0.23, 88.14 ± 17.83 mmHg, and 38.70 ± 4.28 mmHg, respectively. Compared to baseline, lactic acid significantly decreased (2.10 ± 0.50 mmol/L, p = 0.03), while PH increased (7.388 ± 0.27, p < 0.05) after CPAP treatment. In addition, neck circumference and the polysomnographic parameters, including apnea-hypopnea index, oxygen desaturation index (ODI), mean oxygen saturation (SpO₂), and the percentage of sleep time with SpO₂ <90 % (TS90 %), positively correlated with lactate, while age correlated negatively with lactate (all p < 0.05). Significantly positive associations were found between age, neck circumference, and PH; furthermore, a negative correlation was found between ODI and PH. Finally, after adjusting for confounding factors, TS90 % was the major contributing predictor for elevated lactate (p < 0.05), and age was a predictor for an increase in PH (p < 0.05).

CONCLUSIONS

The results indicated that CPAP treatment could reduce serum lactate and increase PH in OSAS patients and might alleviate acid-base balance disorders in OSAS. Furthermore, TS90 % was a risk factor for elevated lactate, and age was independently associated with PH.

Acidemia in severe acute cardiogenic pulmonary edema treated with noninvasive pressure support ventilation: a single-center experience

In clinical practice, acidotic patients with acute cardiogenic pulmonary edema (ACPE) are commonly considered more severe in comparison with nonacidotic patients, and data on the outcome of these patients treated with noninvasive pressure support ventilation (NIV) are lacking.The present investigation was aimed at assessing whether acidosis on admission (pH < 7.35) was associated with adverse outcome in 65 consecutive patients with ACPE treated with NIV and admitted to our Intensive Cardiac Care Unit (ICCU).In our population, 28 patients were acidotic (28 of 65, 43.1%), whereas 41 patients were not (37 of 65, 56.9%). According to the Repeated Measures General Linear Model, pCO2 values significantly changed throughout the 2-h NIV treatment (P = 0.019) in both groups (P = 0001). In acidotic patients, pCO2 significantly decreased (51.9 ± 15.3 → 47.0 ± 12.8 → 44.8 ± 12.7), whereas they increased in the nonacidotic subgroup (36.8 ± 6.5 → 36.9 ± 7.2 → 37.6 ± 6.4). No difference was observed in intubation rate between acidotic (eight patients, 28.6%) and nonacidotic patients (12 patients, 32.4%) (P = 0.738). In-ICCU mortality rate did not differ between (13 patients, 35.1%) and nonacidotic patients (nine patients, 32.1%) (P = 0.801).Our data strongly suggest that in patients with severe ACPE treated with NIV, the presence of acidosis is not associated with adverse outcomes (early mortality and intubation rates) in these patients.

Severe but not mild hypercapnia affects the outcome in patients with severe cardiogenic pulmonary edema treated by non-invasive ventilation

Background

Patients with severe cardiogenic pulmonary edema (CPE) are frequently hypercapnic, possibly because of associated underlying chronic lung disease (CLD). Since hypercapnia has been associated with outcome, we aimed to identify factors associated to hypercapnia and its role on outcome of patients with CPE and no underlying CLD.

Methods

Observational cohort study using data prospectively collected over a 3-year period. After excluding patients with any CLD or obstructive sleep apneas, all patients treated by non-invasive ventilation (NIV) for severe CPE were included. Hypercapnia was defined as PaCO₂ >45 mmHg and non-rapid favorable outcome was defined as the need for intubation or continuation of NIV for more than 48 h.

Results

After excluding 60 patients with underlying CLD or sleep apneas, 112 patients were studied. The rates of intubation and of prolonged NIV were 6.3 % (n = 7) and 21.4 % (n = 24), respectively. Half of the patients (n = 56) had hypercapnia upon admission. Hypercapnic patients were older, more frequently obese, and were more likely to have a respiratory tract infection than non-hypercapnic patients. Hypercapnia had no influence on intubation rate or the need for prolonged NIV. However, patients with severe hypercapnia (PaCO₂ >60 mmHg) needed longer durations of NIV and intensive care unit (ICU) stay than the others.

Conclusions

Among the patients admitted for severe CPE without CLD, half of them had hypercapnia at admission. Hypercapnic patients were older and more frequently obese but their outcome was similar compared to non-hypercapnic patients. Patients with severe hypercapnia needed longer durations of NIV than the others without increase in intubation rate.

Year in review 2010: Critical Care--Respirology

In this review, 21 original papers published last year in the respirology and critical care sections of Critical Care are classified and analyzed in the following categories: mechanical ventilation, lung recruitment maneuvers, and weaning; the role of positive end-expiratory pressure in acute lung injury models; animal models of ventilator-induced lung injury; diaphragmatic dysfunction; the role of mechanical ventilation in heart-lung interaction; and miscellanea.

Prognostic indicators in patients presenting with acute cardiogenic pulmonary edema treated with CPAP: it's not the acid that matters, it's back to basics

Several prognostic markers have been identified for patients admitted with acute cardiogenic pulmonary edema. Most of the markers are based on clinical risk scores. Unlike hypercapnic respiratory failure, acidosis is not an adverse predictor in these patients. Hemodynamic variables that assess pathophysiological mechanisms may be more helpful to guide appropriate management.