title: The efficacy of postoperative incentive spirometry is influenced by the device-specific imposed work of breathing.
abstract: OBJECTIVE
  The study evaluated the impact of the additional imposed work of breathing (WBimp) generated by two different spirometers on postoperative incentive spirometry performance in patients at high risk and moderate risk for postoperative pulmonary complications (PPCs). Additionally, we investigated whether maximal inspiratory pressure (PImax) is an easy estimate of the WBimp imposed by incentive spirometers.
  
  
  METHODS
  Prospective, randomized, single-blind clinical trial.
  
  
  METHODS
  ICU of a university hospital.
  
  
  METHODS
  Thirty male patients were assigned to a group at high risk for PPCs (group A; inspiratory capacity [IC], < 1.6 L) or to a group at moderate risk for PPCs (group B; IC, 1.6 to 2.5 L) after upper-abdominal, thoracic, or two-cavity surgery. On the first or second postoperative day WBimp, IC, and PImax were recorded without spirometers (baseline) and during incentive spirometry with the Mediflo spirometer (Medimex; Hamburg, Germany) (high WBimp) and the Coach spirometer (Kendall; Neustadt, Germany) (low WBimp) using a pneumotachograph. In group A, the baseline and the ICs for both spirometers only differed slightly. In group B, the IC was significantly reduced for the Mediflo (p < 0.05), which imposed a WBimp twice as high as the Coach (p < 0.01). PImax was significantly increased for both the Mediflo and the Coach (p < 0.01). PImax was positively correlated with WBimp (r = 0.8).
  
  
  CONCLUSIONS
  Incentive spirometers differ considerably in their additional Wbimp with a potential impact on the efficacy of postoperative incentive spirometry performance. PImax might be an easy clinical estimate for the WBimp during incentive spirometry. Incentive spirometers with low WBimp permit increased maximal sustained inspiration and, thus, enhanced incentive spirometry performance, and, therefore, it might be more suitable for use in postoperative respiratory care.
authors.affiliation: Department of Ophthalmology, University of the Saarland, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Weindler
authors.forename: R T
authors.initials: RT
authors.lastname: Kiefer
mesh_terms: D006801:Humans; D008297:Male; D008875:Middle Aged; D011182:Postoperative Care; D011184:Postoperative Period; D011446:Prospective Studies; D016037:Single-Blind Method; D013147:Spirometry / Q000295:instrumentation*; D014939:Work of Breathing