title: Mixed acid-base disorders, hydroelectrolyte imbalance and lactate production in hypercapnic respiratory failure: the role of noninvasive ventilation.
abstract: BACKGROUND
  Hypercapnic Chronic Obstructive Pulmonary Disease (COPD) exacerbation in patients with comorbidities and multidrug therapy is complicated by mixed acid-base, hydro-electrolyte and lactate disorders. Aim of this study was to determine the relationships of these disorders with the requirement for and duration of noninvasive ventilation (NIV) when treating hypercapnic respiratory failure.
  
  
  METHODS
  Sixty-seven consecutive patients who were hospitalized for hypercapnic COPD exacerbation had their clinical condition, respiratory function, blood chemistry, arterial blood gases, blood lactate and volemic state assessed. Heart and respiratory rates, pH, PaO(2) and PaCO(2) and blood lactate were checked at the 1st, 2nd, 6th and 24th hours after starting NIV.
  
  
  RESULTS
  Nine patients were transferred to the intensive care unit. NIV was performed in 11/17 (64.7%) mixed respiratory acidosis-metabolic alkalosis, 10/36 (27.8%) respiratory acidosis and 3/5 (60%) mixed respiratory-metabolic acidosis patients (p = 0.026), with durations of 45.1 ± 9.8, 36.2 ± 8.9 and 53.3 ± 4.1 hours, respectively (p = 0.016). The duration of ventilation was associated with higher blood lactate (p<0.001), lower pH (p = 0.016), lower serum sodium (p = 0.014) and lower chloride (p = 0.038). Hyponatremia without hypervolemic hypochloremia occurred in 11 respiratory acidosis patients. Hypovolemic hyponatremia with hypochloremia and hypokalemia occurred in 10 mixed respiratory acidosis-metabolic alkalosis patients, and euvolemic hypochloremia occurred in the other 7 patients with this mixed acid-base disorder.
  
  
  CONCLUSIONS
  Mixed acid-base and lactate disorders during hypercapnic COPD exacerbations predict the need for and longer duration of NIV. The combination of mixed acid-base disorders and hydro-electrolyte disturbances should be further investigated.
authors.affiliation: Fondazione Eleonora Lorillard Spencer Cenci, Sapienza University of Rome, Rome, Italy.
authors.forename: Claudio
authors.initials: C
authors.lastname: Terzano
authors.forename: Fabio
authors.initials: F
authors.lastname: Di Stefano
authors.forename: Vittoria
authors.initials: V
authors.lastname: Conti
authors.forename: Marta
authors.initials: M
authors.lastname: Di Nicola
authors.forename: Gregorino
authors.initials: G
authors.lastname: Paone
authors.forename: Angelo
authors.initials: A
authors.lastname: Petroianni
authors.forename: Alberto
authors.initials: A
authors.lastname: Ricci
mesh_terms: D000142:Acidosis, Respiratory / Q000150:complications* / Q000378:metabolism; D000368:Aged; D000369:Aged, 80 and over; D000472:Alkalosis, Respiratory / Q000150:complications* / Q000378:metabolism; D001784:Blood Gas Analysis; D002245:Carbon Dioxide / Q000097:blood; D002712:Chlorides / Q000097:blood; D004573:Electrolytes / Q000097:blood*; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D006935:Hypercapnia / Q000150:complications*; D007010:Hyponatremia / Q000209:etiology; D007362:Intensive Care Units; D019344:Lactic Acid / Q000097:blood*; D008297:Male; D011237:Predictive Value of Tests; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications* / Q000378:metabolism; D012121:Respiration, Artificial; D012964:Sodium / Q000097:blood; D013997:Time Factors
chemical_list: D002712:Chlorides; D004573:Electrolytes; D002245:Carbon Dioxide; D019344:Lactic Acid; D012964:Sodium