# Chest Physiotherapy > Chest physiotherapy for Respiratory Therapy: ACBT, postural drainage positions, percussion, huffing, incentive spirometry, indications and precautions. - Canonical URL: https://prepelephant.com/topics/allied/respiratory-therapy/chest-physiotherapy-rt - Exam / course: Allied Health · Subject: Respiratory Therapy - Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team - First published: 2026-10-02 - Last updated: 2026-10-02 - How to cite: "Chest Physiotherapy", PrepElephant, https://prepelephant.com/topics/allied/respiratory-therapy/chest-physiotherapy-rt ## Direct answer Gravity, oscillation and controlled breathing clear the secretions a cough cannot reach. The backbone of modern chest physiotherapy is the active cycle of breathing techniques (ACBT) — breathing control, thoracic expansion exercises, and the forced expiration technique or "huff" — performed in postural drainage positions that place the target segment uppermost so mucus travels downhill toward the trachea. Percussion and vibration add mechanical energy, incentive spirometry prevents the basal atelectasis of surgery, and the whole prescription is timed around meals, pain relief and the patient's own cough. What examiners test is not the menu of techniques but the reasoning: which position drains which segment, when head-down is forbidden, and why a huff succeeds where a cough collapses. ## What you must remember - ACBT cycle: breathing control at normal tidal volume, then three to five thoracic expansions with a three-second hold, then breathing control again, then a huff from mid lung volume, coughing only when secretions reach the large airways. - A huff is forced expiration through an open glottis at mid-to-low lung volume: it mobilises peripheral secretions with less airway collapse than a cough — the technique of choice in collapse-prone airways (COPD, bronchiectasis). - Postural drainage positions: head-down (about 15-25 degrees) for basal segments; sitting and leaning forward for apical segments; the segment to be drained is placed uppermost. - Head-down contraindications: raised intracranial pressure, haemodynamic instability, active haemoptysis, recent thoracic or abdominal surgery, gross reflux and late pregnancy — schedule sessions before meals or 1-1.5 hours after. - Percussion: cupped hand over the rib cage of the draining segment, avoiding the spine, kidneys, clavicles, wounds and fractured ribs; contraindicated or modified with osteoporosis, coagulopathy and anticoagulation. - Vibration and shaking: manual oscillation applied through the chest wall during expiration — the gentler option for painful chests. - Incentive spirometry: sustained maximal inspiration with a three-to-five second hold, about ten breaths hourly while awake — post-operative atelectasis prophylaxis after thoracic and upper abdominal surgery. - Sessions run 15-30 minutes, two to four times daily for retained secretions; acute lobar atelectasis should respond within 24-48 hours of frequent treatment plus early mobilisation, or escalation is due. - An effective cough is taught, not assumed: deep inhalation, brief closure, then two or three staged coughs from mid volume, supporting surgical incisions with a pillow. ## Day one after upper abdominal surgery A 58-year-old man, first morning after open cholecystectomy, respiratory rate 24, SpO2 93% on air, basal crackles at the left base, refusing to cough because the incision hurts. Time the session for 30-45 minutes after analgesia, so effort is possible. Sit him on the edge of the bed and put a pillow against the incision. Two ACBT cycles — breathing control to settle, expansions with hold to reopen basal alveoli, then a huff at mid volume, which he tolerates far better than a cough. Teach incentive spirometry: ten sustained breaths hourly while awake. Get him standing and walking — mobilisation is the strongest physiotherapy on the ward. Reassess tomorrow: saturation up, crackles clearing, regimen continuing until discharge. Contrast the bronchiectasis outpatient, whose morning routine is the drainage pyramid in slow motion: head-down side-lying for the lower lobes, tipped prone for posterior segments, sitting forward for apices, with ACBT in each position and the whole session finished before breakfast. ## Where students slip The position rule reverses under exam stress: the affected segment goes uppermost, because mucus drains downhill to the trachea only from an elevated segment — anchor it as "put the pus uphill". Second error: postural drainage immediately after a meal, which converts a therapy session into an aspiration risk; the ward timetable, not convenience, sets the schedule. Third: percussion applied over the spine or the lower back over the kidneys — the exam answer is rib cage over the draining segment only, with vibration substituted wherever bone, wound or fracture intervenes. Finally, the huff is not a "soft cough" — the open glottis and mid-to-low lung volume are the entire mechanism, and saying so earns the mark. ## Frequently asked questions ### What are the three components of the active cycle of breathing techniques? Breathing control, thoracic expansion exercises, and the forced expiration technique (huff), cycled with rest periods. ### When is head-down postural drainage contraindicated? Raised intracranial pressure, haemodynamic instability, active haemoptysis, recent thoracic or abdominal surgery, gross reflux and late pregnancy. ### What is a huff, and when is it preferred to coughing? Forced expiration through an open glottis from mid lung volume; it moves peripheral secretions with less airway collapse, suiting COPD and bronchiectasis. ### When should incentive spirometry start after surgery? As soon as the patient is awake and able, from day zero, ten breaths hourly while awake, alongside early mobilisation. ### How long and how often should clearance sessions run? Fifteen to thirty minutes, two to four times a day for retained secretions, positioned to the affected segments. ### Where should percussion never be applied? Over the spine, kidneys, clavicles, surgical wounds or fractured ribs — use vibration instead when the chest wall is vulnerable.