Intensive Care Medicine

lntens. Care Med. 4, 149 - 153 (1978)

9 by Springer-Verlag 1978

Nasal CPAP Treatment of the Respiratory Distress Syndrome A Prospective Investigation of 10 NewBorn Infants Dorit Theilade The Department of Anaesthetics, Odense University Hospital. Odense, Denmark

Abstract. Ten newborn infants with the idiopathic respiratory distress syndrome (IRDS) or foetal aspiration (FA) were treated with a simplified nasal CPAP system (continuous positive airway pressure). The system consists of a Hudson binasal cannula and a Benveniste pediatric jet device (weight 5 g). The desired airway pressures are obtained by adjustment of the jet flow in accordance with the naso-pharyngeal flow/pressure relationship. The system was found to be effective in the treatment of 9 of the I 0 children, as demonstrated by improved blood gas values, and improved respiration; the latter was also evident in infants with pronounced apnea. In one child pneumothorax, occuring after about 24 hours of successful CPAP treatment, necessitated respirator treatment. The system is quick and simple to use, and permits feeding, lung physiotherapy and routine nursing of the child during treatment. Key words: Nasal CPAP, Respiratory distress syndrome, Apnea in RDS,

The idiopathic respiratory distress syndrome (IRDS) and foetal aspiration (FA) can cause life-threatening lung conditions. Typical symptoms are: cyanosis, inspiratory strider, flaring of the alae nasi together with grunting respiration, brought about by expiration against a partly closed glottis. X-ray examination of the chest shows opacification of the lung fields and an air bronchogram. In 1971 Gregory et al. [10] introduced the use of continuous positive airway pressure (CPAP) for the treatment of atelectases and hypoxaemia in newborn infants with severe IRDS. The treatment was given either via an endotracheal tube, or by means of a plastic pressure chamber. The arterial oxygen tension (PaO2) was improved by this means and consequently the oxygen content of the inspiratory air (FIO:) could be reduced. The pressure chamber has since been employed with various modifications. Some investigators have used a continuous negative pressure (CNP) around the body of the child in order to obtain the

CPAP effect I6, 8, 13]. Others [2, 14] used a close fitting pressurised face chamber or mask. However, such chambers or masks complicate the nursing of the child. The use of an endotracheal tube involves the risk of obstruction, accidental extubation or displacement, as well as pneumonia [41. Several authors [4, 5, 12, 15, 16, 18] have therefore used CPAP administered through specially shaped nasal catheters, thus profiting from the fact that newborn infants only breath through the nose. in the main the pressure systems previously employed consisted of a ventilation balloon with a tube connected to a control manometer, and an excess pressure safety valve consisting of a glass tube with its outlet below the surface ofacolumn of water. The gas flow was adjusted by a regulating screw providing the required positive pressure in the system. In 1968 Benveniste et al. [3 ] described a pediatric gas valve substitute for anaesthesia and artificial ventilation. Brendstrup and Kamper [5] replaced the previous positive pressure systems with the Benveniste valve substitute, and connected this with a Hudson nasal cannula for CPAP treatment of newborn infants with respiratory distress syndrome (RDS). The present author [19] investigated the relationship between various jet flows of the valve substitute and the pressures obtained in the nasopharynx and in the oesophagus while using this system for CPAP treatment. The resulting nasopharyngeal flow/pressure curve makes the use of manometers and excess pressure safety valves unnecessary. The system appeared to possess a stimulating effect in the treatment of apnea, possibly due to an automatically rising pressure effect. This study reports the results of the nasal CPAP treat. ment of RDS in newborn infants, using the Benveniste jet device with the positive airway pressures established according to the nasopharyngeal flow/pressure curve.

Material The investigation includes 10 newborn infants with RDS. Their sex, gestational age, and birth weights are shown in Table 1. All of the I0 patients suffered from respiratory insufficiency and hypoxia and had a Silverman's score of 0342-4642/78/0004/0149/$ 01.00

150

D. Theilade: Nasal CPAP Treatment

Table 1. The physical and clinical data of 10 newborn infants with RDS treated with nasal CPAP Child number

a b c d

Sex

Diagnosis Gesta- Birth tional weight age weeks

grams

Birth CPAP interval h

FiO2 a before Oxygenation in blood l and at commence- Before CPAP After ~-2 men[ of CPAP b h of CPAP PaO2 SOs PaO2 SOs mm Hg % mm Hg %

Dura[ion of CPAP h

Complications

1

9

FA

31

1200

2

0,80

50

122

122

2

r

IRDS

31

1700

9

0,50

49

144

12

sepsis ~ dead (see text)

3

9

IRDS

30

1200

13

0,50

72

82

150

ulceration of nares

4

r

IRDS

32

1900

I

0,55

50

89

13

5

c~

IRDS

37

2100

58

0,60

45

100

65

6

Q

IRDS

39

3550

10

1,00 c 0,60

68

91

22

bilateral pncumothorax. (tubulat, and respirator)

7

~

FA

40

3350

10

0.60

66

77

64

pneumothorax tubulation)

8

d

IRDS

35

2800

6

0,60

69

94

60

slight pneumothorax (no treatment)

9

r

IRDS

36

2670

130

0,60

64

98

42

10

d

FA + IRDS

37

2600

2 I/2

0,60

fraction of inspired oxygen corrected to a temperature of 37 ~ C 1,0 before CPAP; decreased to 0,60 at onset of CPAP-treatment no clinical improvement on CPAP (see text)

more than 5. Blood gas analyses showed a Pa02 o f < 60 mm Hg, or an SO2 (oxygen saturation o f capillary blood) < 80% with 50% oxygen in the inspiratory air or/and a pH < 7.20.

56

I/4 d later (Respirator) 72

o f the jet flow in accordance with the nasopharyngeal flow/pressure relationship (Fig. 1). A jet flow o f 18-20 l/rain was applied at the start o f the CPAP treatment, this resulting in a maximum peak expiratory pressure o f 8 cm H20 in the naso-pharynx (Fig, 1). The same oxygen percentage was used, as that employed in the incubator, prior to the CPAP treatment. In most cases these air flows resulted in a diminution or disappearance ofcyanosis and inspira12

Pressure [cmH20]

Methods

A practically convenient nasal CPAP system constructed from a pediatric jet device (DB valve, Dameca, Denmark) connected to a binasal nose-piece (Hudson pediatric nasal cannula, Hudson Sales Company) was employed for the CPAP treatment; Figure 1 shows the relationship between the jet flows and the nasophryngeal pressures as reported (19). No CPAP effect was registered with flows less than 6 1/min. Oxygen enriched air - supplied from 2 rotameters was brought to the jet device via a thermostatically regulated humidifier. The positive pressure in the airways was created by the air jet: most o f the flow is despersed into the surroundings. The open j e t device allows escape o f condensed water before inflation o f the gas-mixture into the airways. The desired airway pressures were obtained by adjustment

10

O

'

~

'

! 8

FLOW,, [L/mini '

~'2

'

;8

2o

....

Fig. I. The flow/pressure relationship according to pressures recorded in the nasopharynx at various jet flows during nasal CPAP treatment of 11 infants. (From [ 19])

D. Theilade: Nasal CPAP Treatment

tory retractions within a few minutes. A flow of more than 20 1/min was required in only 3 infants, for 3,4 and 7 h, respectively. The flow employed was gradually reduced following improvement in the blood gas analyses. An attempt to reduce the oxygen content of the inspiratory air by I0%, was made after every 2 1 reduction in the flow. When blood gases were normal, with a gas flow of I0 litres/min and inspired oxygen concentration of 40%, and respirations were satisfactory the CPAP trea(ment was discontinued, and the treatment of the child continued in an incubator with 40% oxygen. If pronounced cyanosis persisted during the CPAP treatment despite an inspired oxygen percentage of 80 or if there were repeated periods of apnea of more than 20 s, then this treatment was considered to be insufficient. In such cases ventilation is required. X-ray examination of the lungs was carried out daily during treatment. Blood gas analyses were carried out from 30 min to 2 h after the start of treatment and necessary changes in the flow and oxygen percentage were made accordingly. In the majority of patients the analyses were carried out on capillary blood removed from a heel. At a later period of the investigation a catheter was routinely inserted into the umbilical artery for blood sampling and parenteral infusion. The results are therefore shown as either oxygen saturation of capillary blood or arterial oxygen tension. To determine if the changes in arterial oxygenation during CPAP treatment were due to this treatment, or were spontaneous, the CPAP treatment was discontinued in 4 patients, by reducing the air jet flow to 6 l/rain. The oxygen percentage in the inspiratory air was kept unchanged. The treatment was resumed after a period of 10 min. Before the pause in treatment and at the end, as well as after CPAP treatment had been resumed, samples were taken for blood gas analyses and a clinical evaluation was carried out using Silverman's score. Silverman [17] classified the severity of RDS on a points system of 0 - 10. He distinguished between absent, slight and pronounced inspiratory retractions in the upper chest, intercostal muscles and xiphoid area, with points from 0 - 2 for retractions in each of these sites. Granting and flaring of the nostrils were also graded individually according to their severity, from 0 - 2. The majority of infants were fed parenterally. However, the nasal CPAP treatment did not prevent simultaneous tube feeding. Aspiration to the lungs did not occur. Lung physiotherapy and suction in the pharynx, was carried out hourly throughout the treatment.

Results In 9 infants the oxygen saturation of capillary blood or arterial oxygen tension showed a rise after the start of the CPAP treatment (Table 1). Full restitution under nasal CPAP treatment alone, was observed in 7 infants after an average duration of treatment of 60 h. In child no. 4, with severe initial symptoms (pH 7.06, SO: 50% and pCO2 80 mm Hg), the CPAP could be discontinued after 13 h; this

15 t

child had received CPAP treatment from one h after birth. Child no. 1 (birth weight 1200 g) was similarly subjected to treatment shortly after birth, because of extensive opacification of the lung fields. In this case the chest x-ray was normal 20 h later; however, apnea necessitated the continuation of CPAP treatment. Recurring apnea occurred in all 5 infants with a low birth weight (1200 - 2100 g). Both the respiration and the oxygen saturation or arterial oxygen tension was improved initially in all 5 patients. In cases where apnea alone was present, a maximum flow of 16 1/min was sufficient. One of the 5 children (no. 2), later developed a condition sugestive of ceptic shock and had to be ventilated. Death occurred on the 3rd day and a post-mortem examination showed considerably enlarged lungs with severe hyaline membranes and massive infiltration by coliform bacteria. In addition to this case respirator treatment was necessary for 2 more children; in the one child (no. 6), because of bilateral pneumothoraces, occuring several hours after a reduction in gas flow from 20 l/min, to 16/min. The last child {no. 10) had severe respiratory acidosis (pCO: 136 mm Hg, pH 6.92 and PaO2 56 mm Hg), and after only 15 rain of CPAP treatment it became obvious that this treatment was insufficient. After 3 days of respirator treatment the CPAP treatment was effectively resumed. After approximately only 24 h of CPAP treatment pneumothorax occurred in a total of 3 infants. Two of them were able to continue CPAP treatment; one of them without an intemtal drain. Other complications were: ulceration of the nostrils in one child (no. 3) attributable to the use of the nose-piece. The wound healed without any defect. Additionally, gaseous distension of the stomach necessitated the introduction of a feeding tube in one child. In 8 of the children the pC(3: values were followed during CPAP treatment. A fall in pCO: was seen in all these patients; however, in 3 of them the fall was preceded by a slight rise (Fig. 2). pCO: approximated to normal values after 2 - 5 h of CPAP treatment. Child no. 9 had a high pCO2 throughout the first 4 days of life; this fell within 5 h after the commencement of CPAP treatment to normal values. Too pc~ Cram~] 90

~

80

/

I.,,oo, somo.

~

""8.

I NumbersaccQrdingtO ,abet

1

\4

6O 5O

30

Time [hours] Onset of, PAP

Fig. 2. Changes in PCO2 in 8 infants, following the application of nasal CPAP; the numbers refer to those in Table 1

152

D. Theilade: Nasal CPAP Treatment

Table 2. The effect of CPAP on 4 children (numbered according to Table i) as evaluated before the pause in treatment and at the end, as well as after restarting the CPAP treatment 1.

PaO2 (mm Hg) Silverman Score

CPAP 105 3

No CPAP 87.5 7

CPAP 104 3

2.

PaO2Imm Hg) Silverman Score

65 1

49,8 4

60 t

5.

SO2 (%) Silverman Score

100 3

59 7

98 3

8.

SO: (%) Silverman Score

94 4

83 9

89 2

In 4 patients, control of the effect of CPAP treatment was carried out by evaluation before, during and after a 10 minutes pause in the treatment and this showed a rise in the Silverman's score and a fall in the oxygen saturation or oxygen tension at the end of this interval (Table 2). Following resumption of the CPAP treatment, the values returned to previous levels.

Discussion The value of the nasal CPAP treatment used, has been demonstrated by the clinical results. Further, the control pauses in the treatment, with return to pathologic values of the oxygen saturation or oxygen tension, would also indicate that this type of CPAP treatment is effective. The system is easy to use and treatment can be applied rapidly; furthermore, fixation is simplified by the small size and weight of the nose-piece and the jet device. Accidental compression of the air tube to the jet device, will not prevent the child from inspiring free atmospheric air under normal pressure via the jet device [5]. In addition the open jet device permits condensed water to leave the system prior to inspiration. The CPAP system used facilitates the nursing of the child, in respect of feeding, lung physiotherapy and routine nursing. The most serious complication, excluding those of the child that died, from presumed sepsis due to foetal aspiration, was pneumothorax, which occured in 3 of the I0 infants. Hall and Rhodes [11] demonstrated pneumothorax during CPAP treatment in 20% of their patients. Adler and Wyszogrodski [ 1] showed an increasing incidence of spontaneous pneumothorax, with rising birth weight in patients with RDS. Cohen et al. [7] found pneumothorax in 24 of 234 children with IRDS. Pneumothorax occurred at the earliest, 12 h after birth, and most frequently in association with a high gestational age, inasmuch as the frequency was 26% of infants born in the 39th to 40th week, against 10% of the total. In agreement with this, pneumothorax also occurred in the present investigation in the 3 children with the highest birth weight (2800 - 3550 g). The positive pressure with CPAP treatment (maximum 10 - 12 cm H2 O) may also be thought to contribute to the cause of the pneumothorax. However, pressure measure-

ments in the oesophagus showed positive pressures up to 60 cm H20 or even more during crying and increased muscular tone [19]. It appears most probable that the pneumothorax occurs during such variations in pressure, possibly being accentuated by the CPAP treatment. Thus, reduction of the flow and hence of the CPAP pressure as early as is possible, is considered of great importance, by the author. The importance of early treatment to minimize the rate of complications and the duration of treatment was demonstrated by Mockrim and Bancalari [13]. The rapid recovery of children no. 1 and 4 in this series may indicate that, too. In 4 children, the presence of apnea necessitated continuing CPAP treatment even after a normal chest x-ray had been obtained. This did not require flows exceeding 16 litres/minute. CPAP has thus been found to be indicated for the treatment of moderate attacks of apnea in premature infants. This being in agreement with the findings of Speidel and Dunn [18]. The system employed by the present author furthem~ore has a presumed advantage of the automatically rising pressure in apnoic spells [ 19]. This presumed stimulating pressure effect on the respiration, may however, result in pressures far in excess of those registered in the naso-pharynx during normal respiration [ t9]. Consequently the author must warn against using flows greater than 16 I/min when treating apnea. An increased pCO2 does not appear to be a contraindication to CPAP treatment. Fenner and yon Stockhausen [9] found a significant fall in pCO2 after 30 min of CPAP treatment. The present investigation also showed normalization of an increased pCO: within a few hours. The employed nasal CPAP system provides a non-traumatic and effective treatment of RDS. However, there are several other indications for treatment using this system. It has been employed by the author with good remits for the treatment of respiratory insufficiency in larger infants with pneumonia and atelectasis, as well as in a 3 weeks old child with whooping cough [20]. In addition, the author has found the system well-suited to the treatment of apnea in the newborn with a low birth weight, as well as for the prophylaxis of postoperative ateleetasis in the newborn, after thoraco-abdominat surgery.

References 1. Adler, S.M., Wyszogrodski, I.: Pneumothorax as a function of gestational age; clinical and experimental studies. Pediatrics 87,771 (1975) 2o Ahlstr6m, H., Jonson, B., Svenningsen, N.W.: Continuous positive airway pressure with a face chamber in early treatment of idiopathic respiratory distress syndrome. Acta pediat. stand. 62,433 (1973) 3. Benvieniste, D., Pedersen, J.E.P.: A valve substitute with no moving parts for artificial ventilation in newborn and small infants. Brit. J. Anaesth. 40, 464 (1968) 4. Bossi, E.: Spontanatmung mit kontinuerlichem endexpiratorischem Druck mittels doppelseitiger Nasenkaniile beim Neugeborenen. Mschr. Kinderheitk. 123, 141 (1975) 5. Brendstrup, A., Kamper, J.: Kontinuerligt luftvejsovertryk (CPAP) hoe nyf~bdte red hj~lp af binasalt kateter og gasdyse. Lecture in Dansk p~diatrisk Selskab (1977)

D. Theilade: Nasal CPAP Treatment 6. Chernick, V., Vidyasagar, D.: Continuous negative chest wall pressure for HMD. Pediatrics 49,753 (1972) 7. Cohen, D., Cochran, W., Griscom, N.T., Harris, G.B.C.: Naturally occuring pneumothorax in hyaline membrane disease. Pediat. Res. 7,400 (1973) 8. Fanaroff, A.A., Cha, C.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. Pediat. 82, 921 (1973) 9. Fenner, A., yon Stockhausen, H.B.: Konstanter positiver transpulmonaler Druck bei Patienten mit Atemnotsyndrom w~ihrend Spontanatmung. Z. Geburtsh. Perinat. 177, 215 (1973) I0. Gregory, G.A., Kitterman, J.A., Phibbs, R.H., Tooley, W.H., Hamilton, W.K.: Treatment of the idiopathic respiratory distress syndrome with continuous positive airway pressure. N. Engl. J. Med. 284, 1333 (1971) 11. Hall, R.T., Rhodes, Ph.G.: Pneumothorax and pneumomediastinum in infants with idiopathic respiratory distress syndrome receiving continuous positive airway pressure. Pediatrics 55, 4 (1975) 12. Kattwinket, J.: A device for administration of continuous positive airway pressure by the nasal ronte. Pediatrics 52, l 3 I (1973) 13. Mockrin, L.D., Banealari, E.H.: Early vcrsug de "layed initiation of continuous negative pressure in infants with hyaline membrane disease. Pediatrics 87, 596 (1975)

153 14. Rhodes, P.G., Hall, R.T.: Continuous positive airway pressure delivered by face mask in infants with the idiopathic respiratory distress syndrome. A controlled study. Pediatrics 52, 17 (1973) 15. Risemberg, H.M., Fomufod, A., Hazelbake, N., Nishida, H., Peralta, M.J.: Assisted ventilation with nasal continuous positive airway pressure and its effects on morbidity and mortality in RDS. Johns Hopkins Med. J. 135, 171 (1974) 16. Schmid, E.R., Dangel, P.H.: The use of nasal CPAP in newborns with respiratory distress syndrome. Europ. J. lntens. Care Med. 2, 125 (1976) 17. Silverman, W.A., Andersen, D.H.: A controlled clinical trial of effects of water mist on obstructive respiratory signs, death rate and necropsy findings among premature infants. Pediatrics 17, I 11956) 18. Speidel, B.D., Dunn, P.M.: Use of nasal continuous positive airway pressure to treat severe Recurrent apnea in very preterm infants. Lancet, 1976 II, 658 19. Theilade. D.: Nasal CPAP employing a jet device for creating positive pressure, lntens. Care Med. 4, 145 { 1978} 20. Theilade. D.: Nasal continuous positive airway pressure in the treatment of whooping cough. In print Dorit Theilade, MD Department of Anaesthetics University Hospital D K-5000 ()dense Denmark

Nasal CPAP treatment of the respiratory distress syndrome: a prospective investigation of 10 new born infants.

Intensive Care Medicine lntens. Care Med. 4, 149 - 153 (1978) 9 by Springer-Verlag 1978 Nasal CPAP Treatment of the Respiratory Distress Syndrome A...
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