Acute on chronic respiratory failure complicated by acute lobar atelectasis (original) (raw)
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Respiratory failure in chronic obstructive pulmonary disease
European Respiratory Journal, 2003
Respiratory failure is still an important complication of chronic obstructive pulmonary disease (COPD) and hospitalisation with an acute episode being a poor prognostic marker. However, other comorbid conditions, especially cardiovascular disease, are equally powerful predictors of mortality. The physiological basis of acute respiratory failure in COPD is now clear. Significant ventilation/perfusion mismatching with a relative increase in the physiological dead space leads to hypercapnia and hence acidosis. This is largely the result of a shift to a rapid shallow breathing pattern and a rise in the dead space/tidal volume ratio of each breath. This breathing pattern results from adaptive physiological responses which lessen the risk of respiratory muscle fatigue and minimise breathlessness. Treatment is directed at reducing the mechanical load applied to each breath, correcting specific precipitating factors, e.g. bacterial infection, and maintaining gas exchange. Both bronchodilators and oral corticosteroids can improve spirometric results in exacerbations of COPD and should be routinely offered to patients with respiratory failure. Controlled oxygen is still not always prescribed appropriately and high inspired oxygen concentrations can lead to severe acidosis by either worsening ventilation/perfusion mismatching and/or inducing a degree of hypoventilation. Ventilatory support using noninvasive ventilation has revolutionised the approach to these patients. Acute respiratory failure due to chronic obstructive pulmonary disease remains a common medical emergency that can be effectively managed. More attention should be focused on the prevention of these episodes and identifying the factors which cause early relapse.
Hypercapnic Respiratory Failure in COPD Patients *
CHEST Journal, 2000
Introduction: The clinical course of patients with acute exacerbations of underlying COPD presenting with hypercapnic respiratory failure was reviewed. Methods: This was a retrospective review of 138 episodes of hypercapnic respiratory failure (PaCO 2 > 50 mm Hg and pH < 7.35). Patients were admitted to the West Los Angeles VAMC Medical Intensive Care Unit between 1990 and 1994. Results: Of the 138 hypercapnic episodes, 74 (54%) required intubation. Comparison was made with the 64 cases in which patients responded to medical therapy. Patients requiring intubation had a greater severity of illness, with a higher APACHE II (Acute Physiology and Chronic Health Evaluation II) score (18 ؎ 5 vs 16 ؎ 4; p < 0.01), higher WBC, higher serum BUN, and greater acidosis (pH, 7.26 ؎ 0.07 vs 7.28 ؎ 0.06; p ؍ 0.08). Those with the most severe acidosis (pH < 7.20) had the highest intubation rate (70%) and shortest time to intubation (2 ؎ 2 h), and they required the longest period of time to respond to medical therapy (69 ؎ 60 h). With an initial pH of < 7.25, there was a consistently higher intubation rate. Conversely, those with an initial pH of 7.31 to 7.35 were less likely to be intubated (45%), had a longer time to intubation (13 ؎ 18 h), and had a more rapid response to medical therapy (30 ؎ 18 h). Of those patients requiring intubation, most (78%) were intubated within 8 h of presentation, and the vast majority (93%) by 24 h. Of those patients responding to medical therapy, half (52%) recovered within 24 h and the vast majority (92%) recovered within 72 h. Conclusions: This study provides a better characterization of the response to therapy of COPD patients with hypercapnic respiratory failure. This should be useful in limiting or omitting medical therapy in high-risk patients, thereby avoiding delays in intubation as well as providing a framework for continued therapy in those more likely to improve.
Multidisciplinary Respiratory Medicine, 2016
Background: Hypoventilation produces or worsens respiratory acidosis in patients with hypercapnia due to acute exacerbations of chronic obstructive pulmonary disease (AECOPD). In these patients acid-base and hydroelectrolite balance are closely related. Aim of the present study was to evaluate acid-base and hydroelectrolite alterations in these subjects and the effect of non-invasive ventilation and pharmacological treatment. Methods: We retrospectively analysed 110 patients consecutively admitted to the Internal Medicine ward of Cava de' Tirreni Hospital for acute exacerbation of hypercapnic chronic obstructive pulmonary disease. On admission all patients received oxygen with a Venturi mask to maintain arterial oxygen saturation at least >90 %, and received appropriate pharmacological treatment. Non-Invasive Ventilation (NIV) was started when, despite optimal therapy, patients had severe dyspnea, increased work of breathing and respiratory acidosis. Based on Arterial Blood Gas (ABG) data, we divided the 110 patients in 3 groups: A = 51 patients with compensated respiratory acidosis; B = 36 patients with respiratory acidosis + metabolic alkalosis; and C = 23 patients with respiratory acidosis + metabolic acidosis. 55 patients received only conventional therapy and 55 had conventional therapy plus NIV. Results: The use of NIV support was lower in the patients belonging to group B than in those belonging to group A and C (25 %, vs 47 % and 96 % respectively; p < 0.01). A statistically significant association was found between pCO 2 values and serum chloride concentrations both in the entire cohort and in the three separate groups. Conclusions: Our study shows that in hypercapnic respiratory acidosis due to AECOPD, differently from previous studies, the metabolic alkalosis is not a negative prognostic factor neither determines greater NIV support need, whereas the metabolic acidosis in addition to respiratory acidosis is an unfavourable element, since it determines an increased need of NIV and invasive mechanical ventilation support.
The use of noninvasive mechanical ventilation in COPD with severe hypercapnic acidosis
Respiratory Medicine, 2007
Study Objectives: To compare the effect of noninvasive mechanical ventilation (NIV) in severely acidotic with mildly acidotic patients with acute hypercapnic chronic obstructive lung disease (COPD). Design: Comparison of NIV in consecutively enrolled patients with acute hypercapnic COPD with mild (pH 7.25-7.35) or severe (pHo7.25) acidosis on time to normalise pH and improve PaCO 2 , duration of NIV treatment, length of stay in hospital and survival. Results (meadian (IQR)): Twenty-nine patients had 36 episodes of acute hypercapnic respiratory failure: Seventeen with pHo7.25 and 19 with pH 7.25-7.34. Compared with the mildly acidotic group, the severely acidotic group took a similar length of time for pH to normalise and PaCO 2 improve (12 (6-34) vs 12 (4-28) h, respectively, P ¼ 0:42), with similar duration of NIV treatment (60 (35-96) vs 68 (36-48) h, respectively, P ¼ 0:25) and hospital length of stay (8 (7-18) vs 9 (5-17) days, respectively, P ¼ 0:61). Overall survival was 89%, with 95% in the mild and 82% in the severely acidotic groups. Conclusions: Noninvasive ventilation is effective in the treatment of patients with severe acidosis due to acute hypercapnic COPD.
DOAJ (DOAJ: Directory of Open Access Journals), 2018
Background: Hypoventilation produces or worsens respiratory acidosis in patients with hypercapnia due to acute exacerbations of chronic obstructive pulmonary disease (AECOPD). In these patients acid-base and hydroelectrolite balance are closely related. Aim of the present study was to evaluate acid-base and hydroelectrolite alterations in these subjects and the effect of non-invasive ventilation and pharmacological treatment. Methods: We retrospectively analysed 110 patients consecutively admitted to the Internal Medicine ward of Cava de' Tirreni Hospital for acute exacerbation of hypercapnic chronic obstructive pulmonary disease. On admission all patients received oxygen with a Venturi mask to maintain arterial oxygen saturation at least >90 %, and received appropriate pharmacological treatment. Non-Invasive Ventilation (NIV) was started when, despite optimal therapy, patients had severe dyspnea, increased work of breathing and respiratory acidosis. Based on Arterial Blood Gas (ABG) data, we divided the 110 patients in 3 groups: A = 51 patients with compensated respiratory acidosis; B = 36 patients with respiratory acidosis + metabolic alkalosis; and C = 23 patients with respiratory acidosis + metabolic acidosis. 55 patients received only conventional therapy and 55 had conventional therapy plus NIV. Results: The use of NIV support was lower in the patients belonging to group B than in those belonging to group A and C (25 %, vs 47 % and 96 % respectively; p < 0.01). A statistically significant association was found between pCO 2 values and serum chloride concentrations both in the entire cohort and in the three separate groups. Conclusions: Our study shows that in hypercapnic respiratory acidosis due to AECOPD, differently from previous studies, the metabolic alkalosis is not a negative prognostic factor neither determines greater NIV support need, whereas the metabolic acidosis in addition to respiratory acidosis is an unfavourable element, since it determines an increased need of NIV and invasive mechanical ventilation support.