Abstract:
Nasal cannula apparatus, includes in an inlet tubular fitting sized and configured to directly endwise connect to a source of oxygen, or oxygen and air. The fitting defines an inlet flow passage area A, having a 15 mm external diameter. A pair of tubular prongs is operatively connected with the inlet fitting, and receivable in an infant&#39;s nostrils to deliver oxygen, or oxygen and air flow to the infant, the prongs each having flow passing area A 3 , and A 1 &gt;&gt;A 3 .

Description:
BACKGROUND OF THE INVENTION 
     This invention relates generally to nasal cannula therapy, and more particularly to improvements concerning tubing flow in nasal cannula therapy systems. 
     An accepted modality for respiratory support of the newborn is via a mechanical ventilator. The interface is usually an endrotracheal tube which is passed via the mouth or nose, across the oropharynx, through the trachea and placed in the main stem bronchus. This placement, although physiologically effective, has many side effects such as irritation, trauma, infection, increased work of breathing and even bronchopulmonary dysplasia. In order to overcome the sequelae or shortcomings, a device is needed to deliver via the mechanical ventilator the needed pressures to support the newborn. The ventilator is necessary to support the breathing of those that cannot breath spontaneously on their own either because of prematurity of the breathing mechanism or other congenital pathological conditions which cannot maintain the oxygenation of the patent. Once the patient is able to breath spontaneously, the cannula can be adapted to less invasive modalities which include continuous, positive, airway pressure (CPAP), Bubble CPAP, High Flow or simple oxygen therapy. 
     There is need for a device that can be adapted to all of the above methods by applying specifically designated adapters. This increases the utility of the device. 
     Thus, the needed cannula can be used from the delivery room all the way to patient discharge and meet all the respiratory needs of the newborn. 
     SUMMARY OF THE INVENTION 
     It is a major object of the invention to provide solutions to the above problems and difficulties, and to provide a simple, reliable, adjustable connection or connections between air supply means and nasal cannula tubing, and particularly to provide means enabling assisted intermittent positive pressure in a non-invasive mode. 
     SUMMARY OF THE INVENTION 
     It is a further major object of the invention to provide an improved nasal cannula apparatus that comprises: 
     a) an inlet tubular fitting sized and configured to directly endwise connect to a source of oxygen, or oxygen and air, said fitting defining an inlet flow passage area A, having a 15 mm external diameter, 
     b) a pair of tubular prongs operatively connected with the inlet fitting, and receivable in an infant&#39;s nostrils to deliver oxygen, or oxygen and air flow to the infant, the prongs each having flow passing area A 3 , 
     c) and wherein A 1 &gt;&gt;A 3 . 
     As will be seen, all flow passages between A 1  and A 3  have flow passing cross sectional areas greater than A 3 . Also A 3 , the flow passing area of each prong, has a diameter greater than 1.0 mm, and may preferably be about 2.5 mm. 
     Another object is to provide an inlet fitting having two outlets respectively connected in series with two flexible tubes leading to the two prongs, those tubes typically being of equal length and there being ribbing in the tubes to resist their kinking. 
     A further object is to provide two nasal prongs that fit in an infant&#39;s nostrils, and that have matching curvature along the prong lengths, to match normal curvature of nasal canal. 
     Yet another object is to provide an adapter as for example may be selected from a set of adaptors, to enable ready connection of a nasal cannula inlet fitting to a source of O 2 , or air and O 2 . 
    
    
     
       DRAWING DESCRIPTION 
         FIG. 1  is a view of apparatus incorporating the invention; 
         FIG. 2  is a section taken on lines  2 - 2  of  FIG. 1 , the view of nasal prongs showing lengthwise angularity or curvature; 
         FIG. 3  is a perspective view showing internal ribbing in tubing; 
         FIG. 4  is an axial section taken through a fitting connectable to a ventilator; 
         FIG. 5  is an end view of the  FIG. 4  fitting; 
         FIG. 6  shows use of an intermediate adapter; and 
         FIG. 7  is an axial section taken through  FIG. 6 . 
     
    
    
     DETAILED DESCRIPTION 
     Referring first to  FIG. 1 , a basic form of the invention provides a rigid plastic tubular fitting  100  sized and configured to directly endwise connect at  101  with an oxygen supply ventilator or other oxygen, or oxygen and air, source,  102 , as via bore  102   a . The bore  102   a  is typically a 15 mm ID bore, with ability to connect to other devices and systems. 
     Referring also to  FIG. 4 , the fitting  100  has a flow inlet tubular stem  104  insertible into the bore  102   a  of a ventilator circuit or device  102  that supplies oxygen or mixed air and oxygen. The outer surface  104   a  of stem  104  may be configured, for interference fit, and frictional retention. The fitting has two flow outlets  106   a  and  107   a , extending in parallel relation, and aligned with two tubular stems  106  and  107 . Cannula tubings or ducts  108  and  109  are insertible into stems  106  and  107  for frictional retention, and stem bores  106   a  and  107   a  are sized to retain the typically plastic tubings  108  and  109 , which extend to nasal tubular prongs  110  and  111 , as seen in  FIG. 1 . A rigid plastic flange  112  merges with the two stems  106  and  107 , for finger manipulation of the fitting. 
     Nasal cannula plastic tubing is connected in series with the fitting  100 , and typically include like flexible tubular branches  108  and  109  connected to stems  106  and  107 , and leading to opposite ends of short length tubing connection  120  from which the two nasal prongs  110  and  111  extend sidewardly. See also  FIG. 2 . The prongs  110  and  111  have slight endwise deflection or curvature, to match anatomical curvature of nasal canal. See deviation angles α which are between 2° and 10°. A soft sealing cushion  200  may be employed adjacent the bases of the prongs, to abate leakage of air or O 2  delivered to the prong outlets, and to enhance comfort. 
       FIG. 3  shows ribbing  125 - 127  integral with and projecting radially inwardly in flexible plastic duct branch  109  to stiffen it against extreme bending or kinking that would restrict oxygen or air flow in that duct. Open flow space remains at  128 , within the duct or branch and between the ribs. Both of the flexible elongated branches  108  and  109  may contain such ribs, which are alike and extend lengthwise within the branches. 
     In order to secure a cannula around the patient&#39;s head  141 , the cannula utilizes a securing ring  140  seen in  FIG. 1 . This cannula O-ring uses a soft, silicone material that has four like annular rings  140   a . The soft material will not cause trauma to the head. The rings  140   a  allow the ring  140  to adjustably slide up and down the tubing securely, while providing a frictional grip to the tubing outside surfaces, making it easier to grasp the ring to move it. The securing rings  140   a  are typically also color coded, to differentiate or indicate which size prongs are on the cannula. the cannula tubing itself may have green coloring, to indicate use for oxygen flow. 
     Additional features of the invention include the following:
         i) The ID of the cannula adapter and tubing is larger than the ID opening of the cannula prongs. The prongs at their openings, have the smallest ID of the system. This allows for various oxygen therapy treatments to be effectively delivered through the device. Small bore i.e. less than 1 mm bore size prongs, which restricts flows and limits pressures, is typically not used.   ii) The nasal prongs having a slight curvature, are angled at and near their ends, which allows supplied air to flow precisely into the anatomical curve of the nasal passage. (If a prong rests against cannula wall it may traumatize that wall). The 15 mm adapter allows connection to various respiratory support systems, which in turn allows multiple respiratory support methods to be applied to the infant while in the hospital. The respiratory interface can be used upon the baby at delivery and then remain on the baby while multiple other respiratory support treatments are applied. The 15 mm inlet size allows the device to be used at birth, in labor and delivery, with manual resuscitation bag or automated delivery systems.   iii) With the addition of the unique oxygen adapter, the cannula can connect to oxygen tubing while remaining on the baby, i.e. with prongs in the nose, but also allowing transition from non-invasive mechanical ventilation or non-invasive continuous positive pressure to regular oxygen therapy without changing the O 2  delivery interface, as at a ventilator.   iv) The use of a 15 mm “Y” inlet connector or fitting allows connection of oxygen supply to the inspiratory limb and a supply to the inspiratory limb and a pressure relief valve to the expiratory limb.   v) With the addition of the disclosed oxygen adapter, one can utilize high frequency oscillatory ventilation, via cannula.   vi) The cannula tubing with support ribs on the ID, helps prevent the tube or tubing from kinking. The tubing also may have a translucent tint, preferably green for oxygen therapy.   vii) In order to secure a cannula around the patients head, a cannula embracing O-ring consists of a soft silicone material that has at least three ribs or rings spaced lengthwise of the tubing. The soft material will not cause trauma. The ribs allow a securing ring to slide lengthwise up and down the tubing, securely, while providing a grip to the outside surface, making it easier to grasp the ring to move it. The securing rings are also color coded, to indicate which size prongs are on the cannula.   viii) The device provides a utilitarian aspect to the respiratory needs of the newborn to ventilate the lungs. At birth, some newborns do not have the ability to spontaneously breath. Thus there is a need for the assistance of respiration with mechanical respiration. The inspiratory and expiratory phases are supplied by the ventilator. The delivery can be with an invasive endrotracheal tube or via an external cannula. Once the baby can breathe by itself, a constant pressure is applied by an external cannula to keep the lung airsacks open. With continued clinical improvements the applied constant pressure is substituted with a relative high flow of gas and as decreased. When the clinical condition is stabilized, all external assistance is discontinued.
           The device described herein satisfies the needs for respiratory support in each step described. Therefore, instead of multiple devices being applied, only one device need be utilized from delivery to patient discharge from the hospital.   
               

       FIGS. 6 and 7  show an inlet fitting  100 ′ of nasal cannula device  149  connected at  106 ′ and  107 ′ to cannula tubing  108 ′ and  109 ′ of  FIG. 1 . corresponding to tubing branches  108  and  109 . Fitting  100 ′ has an inlet internal diameter d 7  which is not 15 mm, and an external diameter d 10  which is not 15 mm. An adapter  153  is provided having tubular outlet  102   a ′ that fits the inlet internal diameter d 7  of fitting  100 ′. Intermediate adaptor  153  has a tubular inlet with external diameter d 8  equal to 15 mm, to be receivable in 15 mm bore  157  of air supply ventilator  158 . The area of the ventilator bore is indicated at A 8 . In this way, the cannula device  149 , similar to the  FIG. 1  device, can be adapted to the 15 mm outlet of the ventilator. As O 2  or air and O 2 , flows from the ventilator, through the adapter  153 , through the fitting  100 ′, through tubing  108 ′ and  109 ′ and to the cannula nasal prongs, it encounters flow passages of decreasing cross-sectional areas. 
     Accordingly, the following is provided for connection to the 15 mm bore of O 2  or air and O 2  supply means: 
     a) a nasal cannula device having an inlet fitting of external diameter d 10  where d 10  is not equal to 15 mm, 
     b) an adaptor having an external diameter d 8  equal to 15 mm connected to said supply means bore and an outlet bore of diameter d 9  connected to said device, 
     c) the flow areas of said adaptor and of said device being less than the flow area A 8  of said supply means bore and diminishing in the direction toward nasal prongs defined by said nasal cannula device. See also flow area A 6 .