title: Remifentanil improves breathing pattern and reduces inspiratory workload in tachypneic patients.
abstract: BACKGROUND
  Properly titrated opiates decrease respiratory rate but do not affect tidal volume or induce respiratory acidosis.
  
  
  OBJECTIVE
  To determine whether remifentanil improves breathing pattern or reduces inspiratory effort in patients with acute respiratory failure and tachypnea or rapid shallow breathing.
  
  
  METHODS
  We studied 14 patients who developed tachypnea and/or rapid shallow breathing if the pressure support level was reduced. During pressure support ventilation, each patient received 30-min infusions, separated by 30 min, of remifentanil and placebo. Measurements were obtained before commencing and before stopping each infusion, and after 3 min of unassisted breathing. The main outcomes were rapid shallow breathing index and change in pressure-time product.
  
  
  RESULTS
  Remifentanil did not significantly affect tidal volume. During pressure support ventilation, remifentanil infusion reduced respiratory rate, pressure-time product, and cardiovascular double product (heart rate × systolic arterial pressure) without modifying the sedation score. Mean P(aCO(2)) showed a small and clinically negligible increase during remifentanil, but P(aCO(2)) increased more in the hypercapnic patients than in the normocapnic patients. Remifentanil reduced the rapid shallow breathing index after 3 min of unassisted breathing.
  
  
  CONCLUSIONS
  Remifentanil improved respiratory pattern and decreased inspiratory muscles effort in patients with tachypnea or rapid shallow breathing, but did not affect oxygenation or sedation. Though the acid-base balance did not show clinically relevant changes on average, we cannot exclude the possibility that remifentanil might prolong weaning in hypercapnic patients. (Clinical-Trials.gov registration NCT00665119.)
authors.affiliation: Unità di Terapia Intensiva Polifunzionale, Fondazione Poliambulanza Istituto Ospedaliero, 25124 Brescia, Italy. giuseppe.natalini@gmail.com
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Natalini
authors.forename: Antonella
authors.initials: A
authors.lastname: Di Maio
authors.forename: Antonio
authors.initials: A
authors.lastname: Rosano
authors.forename: Pierluigi
authors.initials: P
authors.lastname: Ferretti
authors.forename: Michele
authors.initials: M
authors.lastname: Bertelli
authors.forename: Achille
authors.initials: A
authors.lastname: Bernardini
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D004417:Dyspnea / Q000188:drug therapy*; D005260:Female; D006801:Humans; D006993:Hypnotics and Sedatives / Q000627:therapeutic use*; D008297:Male; D010880:Piperidines / Q000627:therapeutic use*; D000077208:Remifentanil; D012121:Respiration, Artificial; D018709:Statistics, Nonparametric; D015300:Ventilator Weaning; D014939:Work of Breathing
chemical_list: D006993:Hypnotics and Sedatives; D010880:Piperidines; D000077208:Remifentanil