A sealed abdominal interface was positioned below the diaphragm (the “NeoVest”) to apply synchronized and proportional negative pressure ventilation (NPV) and was compared to positive pressure ventilation (PPV) using neurally adjusted ventilatory assist (NAVA). Both modes were controlled by the diaphragm electrical activity (Edi).
Eleven rabbits (mean weight 2.9 kg) were instrumented, tracheotomized, and ventilated with either NPV or PPV (sequentially) with different loads (resistive, dead space, acute lung injury). Assist with either PPV or NPV was titrated to reduce Edi by 50%.
In order to achieve a 50% reduction in Edi, NPV required slightly more negative pressure (−8 to −12 cm H2O) than observed in PPV (+6 to +10 cm H2O). The efficiency of pressure transmission from the NeoVest into gastric pressure was 69.6% (range 61.3–77.4%). Swings in esophageal pressure were more negative during NPV than PPV, for all conditions, due to transmission of negative pressure. Transpulmonary pressure was lower during NPV. Transdiaphragmatic pressure swings were reduced similarly for PPV and NPV, suggesting equivalent unloading of the diaphragm. NPV did not affect hemodynamics.
It is feasible to apply NPV sub-diaphragmatically in synchrony and in proportion to Edi in an animal model of respiratory distress.
Negative pressure ventilation (NPV), for example, the “Iron Lung,” may offer advantages over positive pressure ventilation.
In the present work, we describe the “NeoVest,” a system consisting of a sealed abdominal interface and a ventilator that applies NPV in synchrony and in proportion to the diaphragm electrical activity (Edi).
This is a preview of subscription content, access via your institution
Subscribe to Journal
Get full journal access for 1 year
only $9.15 per issue
All prices are NET prices.
VAT will be added later in the checkout.
Tax calculation will be finalised during checkout.
Get time limited or full article access on ReadCube.
All prices are NET prices.
The datasets generated during and/or analyzed during the current study are available from the corresponding author on reasonable request.
Newnam, K. M. et al. An integrative review of skin breakdown in the preterm infant associated with nasal continuous positive airway pressure. J. Obstet. Gynecol. Neonatal Nurs. 42, 508–516 (2013).
Thomson, A. The role of negative pressure ventilation. Arch. Dis. Child. 77, 454–458 (1997).
Takahashi, D., Liu, L., Sinderby, C. & Beck, J. Feasibility of neurally synchronized and proportional negative pressure ventilation in a small animal model. Physiol. Rep. 8, e14499 (2020).
Heldt, G. P. & McIlroy, M. B. Distortion of chest wall and work of diaphragm in preterm infants. J. Appl. Physiol. 62, 164–169 (1987).
Guslits, B. G., Gaston, S. E., Bryan, M. H., England, S. J. & Bryan, A. C. Diaphragmatic work of breathing in premature human infants. J. Appl. Physiol. 62, 1410–1415 (1987).
Liu, L. et al. Feasibility of neurally adjusted positive end-expiratory pressure in rabbits with early experimental lung injury. BMC Anesthesiol. 15, 124 (2015).
Brander, L. et al. Neural control of ventilation prevents both over-distension and de-recruitment of experimentally injured lungs. Respir. Physiol. Neurobiol. 237, 57–67 (2017).
Rochon, M. E. et al. Continuous neurally adjusted ventilation: a feasibility study in preterm infants. Arch. Dis. Child. Fetal Neonatal Ed. 105, 640–645 (2020).
Chernick, V. & Vidyasagar, D. Continuous negative chest wall pressure in hyaline membrane disease: one year experience. Pediatrics 49, 753–760 (1972).
Bancalari, E., Gerhardt, T. & Monkus, E. Simple device for producing continuous negative pressure in infants with IRDS. Pediatrics 52, 128–131 (1973).
Fanaroff, A., Cha, C., Sosa, R., Crumrine, R. S. & Klaus, M. H. Controlled trial of continuous negative external pressure in the treatment of severe respiratory distress syndrome. J. Pediatr. 82, 921–928 (1973).
Yoshida, T. et al. Continuous negative abdominal pressure recruits lungs at lower distending pressures. Am. J. Respir. Crit. Care Med 197, 534–537 (2018).
Smith, I. E., King, M. A. & Shneerson, J. M. Choosing a negative pressure ventilation pump: are there any important differences? Eur. Respir. J. 8, 1792–1795 (1995).
Stahlman, M. T. et al. Negative pressure assisted ventilation in infants with hyaline membrane disease. J. Pediatr. 76, 174–182 (1970).
Linton, D. M. Cuirass ventilation: a review and update. Crit. Care Resusc. 7, 22–28 (2005).
Stern, L., Ramos, A. D., Outerbridge, E. W. & Beaudry, P. H. Negative pressure artificial respiration: use in treatment of respiratory failure of the newborn. Can. Med. Assoc. J. 102, 595–601 (1970).
Hassinger, A. B., Breuer, R. K., Nutty, K., Ma, C. X. & Al Ibrahim, O. S. Negative-pressure ventilation in pediatric acute respiratory failure. Respir. Care 62, 1540–1549 (2017).
D’Angelo, E., Pecchiari, M., Acocella, F., Monaco, A. & Bellemare, F. Effects of abdominal distension on breathing pattern and respiratory mechanics in rabbits. Respir. Physiol. Neurobiol. 130, 293–304 (2002).
Blankman, P., Hasan, D., van Mourik, M. S. & Gommers, D. Ventilation distribution measured with EIT at varying levels of pressure support and neurally adjusted ventilatory assist in patients with ALI. Intensive Care Med. 39, 1057–1062 (2013).
Levy, R. D., Bradley, T. D., Newman, S. L., Macklem, P. T. & Martin, J. G. Negative pressure ventilation. Effects on ventilation during sleep in normal subjects. Chest 95, 95–99 (1989).
Alexander, G., Gerhardt, T. & Bancalari, E. Hyaline membrane disease. Comparison of continuous negative pressure and nasal positive airway pressure in its treatment. Am. J. Dis. Child 133, 1156–1159 (1979).
Easa, D., Mundie, T. G., Finn, K. C., Hashiro, G. & Balaraman, V. Continuous negative extrathoracic pressure versus positive end-expiratory pressure in piglets after saline lung lavage. Pediatr. Pulmonol. 17, 161–168 (1994).
Mahmood, S. S. & Pinsky, M. R. Heart-lung interactions during mechanical ventilation: the basics. Ann. Transl. Med. 6, 349 (2018).
Shekerdemian, L. & Bohn, D. Cardiovascular effects of mechanical ventilation. Arch. Dis. Child. 80, 475–480 (1999).
Bancalari, E., Garcia, O. L. & Jesse, M. J. Effects of continuous negative pressure on lung mechanics in idiopathic respiratory distress syndrome. Pediatrics 51, 485–493 (1973).
Cvetnic, W. G., Cunningham, M. D., Sills, J. H. & Gluck, L. Reintroduction of continuous negative pressure ventilation in neonates: two-year experience. Pediatr. Pulmonol. 8, 245–253 (1990).
The authors wish to thank M. Norman Comtois for his help with the analysis software and M. Greg Phillips for his work on the 3D printing of the NeoVest.
The study was supported by the St. Michael’s Hospital Foundation (Angels Den Award), The Global Health Innovation Award, and the RS McLaughlin Fund.
D.B. and C.S. have made inventions related to neural control of mechanical ventilation that are patented. The patents are assigned to the academic institution(s) where inventions were made. The license for these patents belongs to Maquet Critical Care. Future commercial uses of this technology may provide financial benefit to D.B. and C.S. through royalties. D.B. and C.S. each own 50% of Neurovent Research Inc. (NVR). NVR is a research and development company that builds the equipment and catheters for research studies. NVR has a consulting agreement with Maquet Critical Care. St. Michael’s Hospital has a research agreement with Maquet Critical Care AB (Solna, Sweden) and receives royalty and overhead from this agreement. The remaining authors have no competing interests to declare.
Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
About this article
Cite this article
Beck, J., Li, HL., Lu, C. et al. Synchronized and proportional sub-diaphragmatic unloading in an animal model of respiratory distress. Pediatr Res (2022). https://doi.org/10.1038/s41390-022-02238-x