Manual hyperinflation partly prevents reductions of functional residual capacity in cardiac surgical patients - a randomized controlled trial

Abstract

IntroductionCardiac surgery is associated with post-operative reductions of functional residual capacity (FRC). Manual hyperinflation (MH) aims to prevent airway plugging, and as such could prevent the reduction of FRC after surgery. The main purpose of this study was to determine the effect of MH on post-operative FRC of cardiac surgical patients.MethodsThis was a randomized controlled trial of patients after elective coronary artery bypass graft and/or valve surgery admitted to the intensive care unit (ICU) of a university hospital. Patients were randomly assigned to a "routine MH group" (MH was performed within 30 minutes after admission to the ICU and every 6 hours thereafter, and before tracheal extubation), or a "control group" (MH was performed only if perceptible (audible) sputum was present in the larger airways causing problems with mechanical ventilation, or if oxygen saturation (SpO2) dropped below 92%). The primary endpoint was the reduction of FRC from the day before cardiac surgery to one, three, and five days after tracheal extubation. Secondary endpoints were SpO2 (at similar time points) and chest radiograph abnormalities, including atelectasis (at three days after tracheal extubation).ResultsA total of 100 patients were enrolled. Patients in the routine MH group showed a decrease of FRC on the first post-operative day to 71% of the pre-operative value, versus 57% in the control group (P = 0.002). Differences in FRC became less prominent over time; differences between the two study groups were no longer statistically significant at Day 5. There were no differences in SpO2 between the study groups. Chest radiographs showed more abnormalities (merely atelectasis) in the control group compared to patients in the routine MH group (P = 0.002).ConclusionsMH partly prevents the reduction of FRC in the first post-operative days after cardiac surgery.Trial registrationNetherlands Trial Register (NTR): NTR1384. http://www.trialregister.nl

Benefits and risks of manual hyperinflation in intubated and mechanically ventilated intensive care unit patients: a systematic review

“…However, in another study of postcardiac surgery patients, this could not be confirmed [24], nor in studies of patients with atelectasis [5], nor in a study of brain-injury patients [23]. Notably, although no effect of MH on arterial oxygenation was found in a study of patients with acute lung injury [20], another study found MH to improve arterial oxygenation in patients with indirect acute lung injury but not in patients with direct acute lung injury [7,33].…”

“…We included 13 interventional studies (six randomized controlled trials of MH [5,20-24], two randomized crossover trials comparing MH with endotracheal suctioning [25,26], four randomized crossover trials comparing MH with hyperinflation by the mechanical ventilator [27-30], and one randomized crossover trial comparing two different manual-ventilation bags [31]), and six observational studies [7,8,32-35]. Physiological end points were respiratory mechanics [20-22,25,27-31], arterial oxygenation [5,20-24,26-28,30,31], and clearance of airway secretions [5,26,27,29-31].…”

“…Physiological end points were respiratory mechanics [20-22,25,27-31], arterial oxygenation [5,20-24,26-28,30,31], and clearance of airway secretions [5,26,27,29-31]. Clinical end points included duration of mechanical ventilation [21,23], length of stay [21,23], and incidence of pneumonia [23].…”

Year in review 2011: Critical Care - respirology

“…The patient is disconnected from the ventilator and the lungs are inflated by using a resuscitation bag with a larger-than-normal breath at a slow inspiratory flow rate, an inspiratory pause, and a high peak expiratory flow that is achieved by the rapid release of the resuscitation bag. Paulus and colleagues [61] conducted a randomized controlled trial in 100 patients admitted to a single ICU after elective coronary artery bypass graft or cardiac valve surgery or both. In the treatment group, manual hyperinflation was performed within 30 minutes after ICU admission and every 6 hours thereafter as well as before extubation.…”

The removal-associated sepsis prevention trial in preterm newborns was ended in an untimely manner

“…The catheter-transducer systems are connected to the patient's circulation via fluid-filled tubing, which may have other components attached (e.g., stopcocks or extensions). System reliability is best when the catheters and tubing are stiff, the mass of the fluid is small, the number of stopcocks limited, and the length of the connecting tubing is not excessive (3,4). Even if these conditions are taken into account, dynamic response artifacts are frequently encountered in patients admitted to intensive care units, catheterization laboratories, and operating rooms (2).…”