A Protocol for Treating Atelectasis in the Chronically Ventilated Pediatric PatientEliezer Be’eri MBBCh, Nitay Fraenkel MD, Orit Bartov BSc. MPt. Ped, Noah Eisenberg BPT, Rachelle Lavi B Physio, Ofra Ginat BPT, Ma’ayan Shoffer BPT.Department of Respiratory RehabilitationAlyn Pediatric Rehabilitation HospitalJerusalem, IsraelPresented at the 2nd meeting of the International Society of Pediatric Respiratory Diseases (INSPiRED), 2024.ORCID ID (Eliezer Be’eri): 0000-0003-4935-6000Email addresses of authors:Eliezer Be’eri: [email protected] Fraenkel: [email protected] Bartov: [email protected] Lavi: [email protected] Eisenberg: [email protected] Ginat: [email protected]’ayan Shoffer: [email protected] should be addressed to:Eliezer Be’eri, MDALYN Hospital84 Shmaryahu Levin Street, Jerusalem, Israel 91090Phone: +972 [email protected] words: Atelectasis, physiotherapy, tracheostomy, mechanical ventilationAbbreviated title: Protocol for treating atelectasisTo the editor,Lung atelectasis is an important complication occurring in children and adolescents who are ventilator-dependent due to neuromuscular respiratory failure. It may occur if a “low tidal volume” ventilation strategy is used, as is commonly done to avoid barotrauma when ventilating subjects with parenchymal respiratory failure. However, the patient in respiratory failure due to neuromuscular disease, in contrast to the subject with parenchymal respiratory failure, is primarily at risk for alveolar de-recruitment, rather than barotrauma. Some authorities have therefore advocated using a “high tidal volume strategy” \RL1. In the short term, atelectasis causes ventilation-perfusion mismatch, but if left untreated it may become a focus of recurrent infection and eventual bronchiectasis. When atelectasis is identified, it is therefore essential to re-recruit the atelectatic lung segment as early as possible, prior to the atelectasis becoming permanent.A standardized protocol for treating newly diagnosed atelectasis in ventilator-dependent children has been developed and implemented in the Respiratory Rehabilitation Department of Alyn Pediatric Rehabilitation Hospital in Jerusalem, Israel. The protocol aims to achieve rational medical and physiotherapy (PT) resource management in a stepwise and time-limited manner. The protocol employs the full spectrum of medical and physiotherapy modalities available at Alyn Hospital, including alveolar recruitment by means of prolonged “sigh” inhalations, mechanical inexsufflation (MIE), intrapulmonary percussive ventilation (IPPV), Vest therapy, negative-pressure cuirass ventilation (RTX), “green-bag” manual hyperinflation and bronchoscopy, and is detailed in diagram 1.The initial step is to maximize the ventilator parameters (peak inspiratory pressure (PIP) or tidal volume (Vti), and peak end expiratory pressure (PEEP)) and add a sigh recruitment manoeuvre of 40 cmH2O for 10 seconds every 20 minutes. In our experience, addition of the sigh recruitment maneuver often succeeds in opening the atelectatic segment, and no further therapy is needed. After 24 hours a chest Xray is performed. If no clinical (oxygen saturation above 94% or return to pre-atelectasis baseline) or radiological improvement has occurred, physiotherapy treatments are then added in a stepwise manner every 48 hours. Our initial physiotherapy protocol comprises manual chest vibration and ventilation-enhancement maneuvers combined with patient positioning to enhance postural drainage. Such positioning may be prone, or lying on the side with the atelectatic lung superior, and may include use of an abdominal belt to improve diaphragmatic function. Manual physiotherapy is combined with MIE and either IPPV (for tracheostomized subjects) or Vest therapies (if the subject is using non-invasive positive-pressure ventilation (NIPPV)), all performed three times a day. Whereas the Vest and IPPV achieve secretion mobilization (essentially, shaking secretions free of the tracheo-bronchial wall), MIE performs secretion removal (moving the secretions up the airways towards the pharynx). The protocol aims to combine mobilization and removal modalities synergistically. If no clinical improvement has occurred after 48 hours, the physiotherapy modality is changed to use of a negative-pressure cuirass (RTX) in secretion removal mode. Our rationale in choosing this technique is that during negative-pressure ventilation, chest wall expansion occurs in a manner that is morphologically different from the manner in which the thorax expands during positive-pressure ventilation, reflecting the difference between “inflating” the lungs from within versus expanding the chest wall from without. We postulate that this morphological difference manifests also at the level of the airways, meaning that there may be differences between positive-pressure and negative-pressure ventilation in terms of how airways physically expand when exposed to these two modalities. If that is in fact true, negative-pressure ventilation may succeed in achieving alveolar recruitment when positive-pressure ventilation has failed to do so. Indeed, in our experience we have witnessed successful recruitment of an atelectatic segment within 24 hours of initiating negative-pressure ventilation, in cases in which the initial positive-pressure ventilation combined with secretion-mobilization methodologies for 72 hours had failed to achieve such. In particularly resistant cases we have also combined RTX ventilation with simultaneous and synchronous positive-pressure ventilation.In children younger than 2 years of age it may be difficult to successfully fit a negative-pressure cuirass to a small thorax, which precludes using that therapy as a next step after failure of first-line PT techniques. In such circumstances, we employ a technique for achieving prolonged lung insufflation using an anesthesiology “green bag” manual resuscitator. In this technique, a slow, prolonged inspiration with a sustained inspiratory pause is followed by rapid release during the expiratory phase. As small children generally still have a pliable chest wall, this technique can often be effective in achieving sustained and high PEEP levels, encouraging alveolar recruitment.We reserve bronchoscopy for those cases in which no ongoing improvement has been achieved after one week of recruitment-enhancing therapies. This is due to a combination of the invasiveness of the procedure with the low likelihood (in our experience) that bronchoscopy alone will achieve re-expansion of an atelectatic lung segment (unless such atelectasis has been caused by a solid, aspirated foreign body that can be removed).In summary, the described protocol is a pathway for opening a newly diagnosed atelectasis in a chronically ventilated child, in a manner that maximizes the number of potentially beneficial treatment modalities employed in a time-limited and rational framework.Abbreviations:PT: physiotherapyMIE: mechanical inexsufflationIPPV: intrapulmonary percussive ventilationNIPPV: non-invasive positive-pressure ventilationRTX: negative-pressure cuirass ventilationPIP: peak inspiratory pressureVti: inspired tidal volumePEEP: peak end expiratory pressure