Continuous positive airway pressure breathing (CPAP)

Size: px

Start display at page:

Download "Continuous positive airway pressure breathing (CPAP)"

Cuthbert Little
5 years ago
Views:

Anaesthesia, 1975, Volume 30, pages 67-72 APPARATUS Continuous positive airway pressure breathing (CPAP) Apparatus for use in neonates or adults A. D. CREW, E. WALL AND P. I.

1 Anaesthesia, 1975, Volume 30, pages APPARATUS Continuous positive airway pressure breathing (CPAP) Apparatus for use in neonates or adults A. D. CREW, E. WALL AND P. I. VARKONYI Since the report by Gregory' of an improvement in the mortality of respiratory distress syndrome of the newborn, associated with the use of spontaneous ventilation at a positive airway pressure (CPAP); these results have been confirmed by other investigators using either a head endotracheal int~bation~-~ or continuous negative pressure (CNP) to the trunk below the The mechanism of CPAP and CNP is essentially the same. Others have attempted to avoid the inconveniences of the headbox technique, and the potential complications of endotracheal intubation, and applied CPAP in neonates via a face mask"*'2 or twin nasal or nasopharyngeal tubes.i3-l7 The use of the technique in adults has been described'* and the authors have found CPAP to be frequently of value in the adult patient following cardiothoracic operations (unpublished data). CPAP is undoubtedly of value in the post-operative care of children following cardiac s~rgery,'~-~' becoming a suitable alternative to mechanical ventilation when the cardiovascular state becomes stable,lg however, limitations to its use following cardiothoracic operations in children have been de~cribed.'~ The authors consider that the fluctuating airway pressure produced by a mechanical resistance to expiratory flow is not entirely satisfactory, particularly in larger patients, because it is dependent on the fresh gas supply rate and inspiratory flow rates achieved by the patient. A circuit has therefore been devised which is essentially a modified T-piece (Fig. 1). The positive airway pressure is applied by leading the expiratory limb to an underwater blow-off, the depth of the water in the reservoir being variable. A fresh gas flow sufficient to maintain the underwater blow-off bubbling continuously during all phases of the respiratory cycle will produce a constant positive airway pressure. Undoubtedly this circuit can be improvised but great care must be taken in the selection of apparatus, particularly with respect to humidification, dead space, airway resistance, and gas flows. There is an oxygen and an air flowmeter on the apparatus but standard flowmeters do not supply sufficient gas flow within their calibrated range to cope with the peak inspiratory flow rates of older patients. A supplemental gas inlet (Fig. 1) allows high A. D. Crew, FFARCS, Consultant Anaesthetist and E. Wall, Physics Technician, Leeds Regional Thoracic Surgical Centre, Killingbeck Hospital, Leeds LS14 6UQ and P. I. Varkonyi, MD, Orzagos Kardiologiai Intezet, Budapest. (Correspondence to be addressed to Dr A. D. Crew.) 67

2 68 A. D. Crew, E. Wall and P. I. Varkonyi 1 Humidified fresh Supplementary Reservoir t Water reservoir and blow -off Fig. 1. Diagramatic representation of the CPAP circuit. flows of air to be injected into the system from an alternative source such as an air compressor. The resistance to flow of the expiratory limb of the apparatus is not practically significant at flows up to 50 litres per minute (Fig. 2). The oxygen content of the inspired gas taken from the flowmeters is unaffected by the injection of supplemental air because the volume of the expiratory limb is in the order of 400 ml. A reservoir bag (Fig. 1) has been included in the circuit in order to accommodate the occasional high peak flows of larger patients and prevent a negative airway pressure occuring during inspiration. If the reservoir bag is removed the patient breathes the same humidified oxygen and air mixture, but at ambient pressure. A robust, lightweight, disposable double-lumen tube (British Oxygen Company) (Fig. 3) carries the inspiratory line inside the expiratory limb of the circuitz4 (Fig. 1) the inspired gas maintains its temperature and humidity with less condensation in the inspiratory line. The heated humidifier (Ohio) can produce a relative humidity quoted as 96% at body temperat~re.~~ The effective dead space of this system is in the order of 4 ml. The fresh gas should be supplied warmed and humidified, and the dead space of the apparatus reduced to a minimum for the treatment of neonates. The extension of 2 0 I N Fresh gas flow rate (1 /minute) Fig. 2. Resistance to flow of the expiratory limb measured with a vernier reading water manometer.

3 CPAP for neonates or adults 69 Fig. 3. Seven-day-old patient breathing spontaneously on CPAP following the repair of a diaphragmatic hernia. The nipple for the injection of supplementary air is not visible in this illustration. the inspiratory gas supply line through the wall of the expiratory limb of the double lumen tube and the use of an adaptor to the head-harness (Figs 3 and 4)26 reduces the dead space of the system to less than I m1.26 The resistance to expiration of the circuit at fresh gas flows of 20 litres per minute is 1 cm water with this modification. A headharness (Fig. 5) has been designed to apply CPAP to neonates via twin nasai or nasopharyngeal tubes, the flow resistance of which is in the order of that of a 7 mm endo-

4 70 A. I?. Crew, E. Wall and P. I. Varkonyi Fig. 4. Modification of the double lumen tube to give minimal dead space, complete with head-harness. Fig. 5. Head-harness for the application of CPAP via twin nasal or nasopharyngeal tubes. Nasal tubes of different sizes have been used in this illustration.

CPAP for neonates or adults 71 tracheal tube. Nasal tubes of different sizes may be used if necessary. The dead space of the system is less than 1.5 ml.

5 CPAP for neonates or adults 71 tracheal tube. Nasal tubes of different sizes may be used if necessary. The dead space of the system is less than 1.5 ml. No need has been found for high or low pressure alarms; obstruction of the expiratory pathway of the circuit is unlikely because of the design of the double lumen tube; the cessation of the underwater blow-off gives adequate audible warning of accidental disconnection. Summary CPAP is a technique of respiratory care which was originally described in the management of the respiratory distress syndrome of the newborn and later in the post operative management of the cardiac infant following surgery. It has potential value in the respiratory management of older children and adults. Apparatus is described suitable for the application of continuous airway pressure during spontaneous ventilation via endotracheal tube in either neonates or adults. The inspired oxygen content is adjustable and the fresh gas warmed and humidified. High and low pressure alarms are not considered necessary. A head-harness is described for the application of CPAP in neonates via twin nasal or nasopharyngeal tubes. This equipment may be obtained from Messrs. Lusterlite Products Limited, 56 Devon Road, Leeds 2. References 1. GREGORY, G.A., KITTERMAN, J.A., PHIBBS, R.H., TOOLEY, W.H. & HAMILTON, W.K. (1971) Treatment of the idiopathic respiratory distress syndrome with continuous airway pressure. New England Journal of Medicine, 284, BARRIE, H. (1972) Simple method of applying continuous positive airway pressure in respiratorydistress syndrome. Lancet, i, DUNN, P.M., THEARLE, M.J., PARSONS, A.C. &WATTS, J.L. (1971) Respiratory distress syndrome and continuous positive airway pressure. Lancet, 2, CUMARASAMY, N., NUSSLI, R., VISCHER, D., DANGEL, P.H. & Duc, G.V. (1973) Artificial ventilation in hyaline membrane disease; the use of positive end-expiratory pressure and continuous positive airway pressure. Pediatrics, 51, MACDONALD, T.H. & SPIERS, A.L. (1971) Continuous positive airway pressure in respiratorydistress syndrome. Lancet, ii, DELEMOS, R.A., MCLAUGHLIN, G.W., DISERENS, H.W. & KIRBY, R.R. (1972) Assisted ventilation in the treatment of hyaline membrane disease. The use of C.P.A.P. with or without assisted ventilation utilising a single ventilator. Pediatric Research, 6, BANCALARI, E., GARCIA, O.L. & JESSE, M.J. (1973) Effects of continuous negative pressure on lung mechanics in idiopathic respiratory distress syndrome. Pediatrics, 51, VIDYASAGAR, D. & CHERNICK, V. (1971) Continuous positive transpulmonary pressure in hyaline membrane disease, a simple device. Pediatrics, 48, FANAROFF, A.A., CHA, C.C., SOSA, R., CRUMRINE, R.S. & KLAUS, M.H. (1973)Controlled trial of continuous negative external pressure in the treatment of severe respiratory distress syndrome. Journal of Pediatrics, 82, CHERNICK, V. (1973) Continuous negative chest wall pressure therapy for hyaline membrane disease, Pediatric Clinics of North America, 20,2, HARRIS, T.R. (1972) Continuous positive airway pressure applied by face mask. Pediatric Research, 6, SHANNON, D.C., LUSSER, M., GOLDBATT, A. & BUNNEL, J.B. (1972) The cyanotic infant. Heart disease or lung disease. New England Journal of Medicine, 287, CALIUMI-PELLEGRINI, G., AGOSTINO, R., ORZALESI, M., NODARI, s., MARZETTI, G., SAVIGNONI, P.G. & BUCCI, G. (1974) Twin nasal cannula for administration of continuous positive airway pressure to newborn infants. Archives of Disease in Childhood, 49,228.

6 72 A. D. Crew, E. Wall and P. I. Varkonyi 14. BUCCI, G., MARZETTI, G., PICECE-BUCCI, S., NODARI, S., AGOSTINO, R. & MORETTI, C. (1974) Phrenic nerve palsy treated by continuous positive pressure breathing by nasal cannula. Archives of Disease in Childhood, 49, AGOSTINO, R., ORZALESI, M., NODARI, S., MENDICINI, M., CONCA, L., SAVIGNONI, P.G., PICECE- Buccr, S., GALLIUMI, G. & BUCCI, G. (1973) Continuous positive airway pressure (CPAP) by nasal cannula in the respiratory distress syndrome (RDS) of the newborn. Pediatric Research, 7, KATTWINKEL, J., FANAROFF, A., CHA, C., FLEMING, D., SOSA, R., CRUMRINE, R. & KLAUS, M. (1973) Controlled trial of continuous positive airway pressure (C.P.A.P.) in R.D.S., and a simplified application by the nasal route. Pediatric Research, 7, NOVOGRODER, M., MACKUANYING, N., EIDELMAN, A.I. & GARTNER, L.M. (1973) Nasopharyngeal ventilation in respiratory distress syndrome (a simple and efficient method of delivering continuous positive airway pressure). The Journal of Pediatrics, 82, SCHMIDT, G.B., BENNETT, E.J. & BOMBECK, C.T. (1974) The use of continuous positive airway pressure (CPAP) in the aduit respiratory distress syndrome. In: First World Congress On Intensive Care Scientific Abstracts (Ed. by I. M. Ledingham), p. 70. Bell & Bains Limited, Glasgow. 19. CREW, A.D., VARKONYI, P.I., GARDNER, L.G., ROBINSON, Q.L.A., WALL, E. & DEVERALL, P.B. (1974) Continuous positive airway pressure breathing in the post operative management of the cardiac infant. Thorax, 29, HALLER, J.A., DONAHOO, J.S., WHITE, J.J., MOYNIHAN, P.C. & GALVIS, A.C. (1973) Use of continuous positive airway pressure in the improved post operative management of neonatal respiratory emergencies. Annals of Thoracic Surgery, 15, HATCH, D.J., TAYLOR, B.W., GLOVER, W.J., COGSWELL, J.J., BATTERSBY, E.F. & KERR, A.A. (1973) Continuous positive airway pressure after open heart operations in infancy. Lancet, 2, STEWART, S., EDMONDS, L.H., KIRKLIN, J.W. & ALLARDE, R.R. (1973) Spontaneous breathing with continuous positive airway pressure after open intracardiac operations in infants. Journal of Thoracic and Cardiovascular Surgery, 65, DEVERALL, P.B. & CREW, A.D. (1974) Intensive care of infants with special reference to respiratory management. British Health Care and Technology. Intensive Care. p. 30 Health & Social Service Journal/Hospital International. London. 24. BUSHMAN, J.A. & ROBINSON, J.S. (1968) A single ventilator hose. British Journal of Anaesthesia, 40, HAYES, B. & ROBINSON, J.S. (1970) An assessment of methods of humidification of inspired gas. British Journal of Anaesthesia, 42, CREW, A.D., WALL, E. & WRIGHT, C.J. (1971) A paediatric nasotracheal tube connection (for use in prolonged nasotracheal intubation and ventilation of neonates). Anaesthesia, 26, 372.

Continuous positive airway pressure breathing in the

Thorax (1974), 29, 437. Continuous positive airway pressure breathing in the postoperative management of the cardiac infant A. D. CREW, P. I. VARKONYI', L. G. GARDNER2, Q. L. A. ROBINSON3, E. WALL, and