28 Fisioterapie, Ju n ie 1982, dee! 38, n r 2 THE EFFECTS OF CHEST PHYSIOTHERAPY AND TRACHEOBRONCHIAL SUCTIONING ON tcP02 IN MECHANICALLY VENTILATED NEWBORN INFANTS P. G O U N D E N , N .D .P . (S.A.), Dip- T.P .* S U M M A R Y This research p roject was planned to investigate the problem o f h y p oxaem ia which occurred in the n e o natal age group as a result o f chest physiotherapy. The stu d y was conducted on m echanically ven tila ted in fa n ts under the age o f one month. Nine studies were carried out, these being divided into 3 categories: ( I) The assessm ent studies, which were p la nned to investigate the e ffe ct o f the existing m e th o d o f chest phy sio th e ra p y to t c P 0 2 (transcutaneous oxygen tension). From the results it was d e a r th a t there was n e ed f o r revision in the e xisting m ethod. (2) The p relim inary studies were designed to establish the o p tim u m levels in the fo llo w in g com ponents o f chest physiotherapy: the correct oxygen concentration f o r hyperventilation during chest physiotherapy: the correct suction pressure fo r tracheobronchial suclioning in the neohate: the m ost suitable m anual ventilation system f o r the neonate. (3) The fin d in g s o f the p relim inary studies were used to fo r m u la te an upgraded method. This m e th o d was teste d against the new m e th o d which involved the use o f a m echanical vibrator. It was f o u n d that excessive handling o f the infant exposed it to significant f a lls in t c P 0 2. O P S O M M IN C , H ierdie navorsingsprojek is beplan out die probleem van h ip o ksie as g evolg van fis io te ra p ie in die neonatale ouderdomsgroep, te ondersoek. D ie ondersoek is gedoen op suigelinge, onder die ouderdom van een maand, wat meganies geventileer is. Nege studies is gedoen, verdeel in 3 kategoriee: (I) Evalueringsstudies, wat beplan is om die e ffe k van die liuidige borskasfisioterapie m elode op IcP O , ( transkutane s u u r s to f spanning) te ondersoek. Van die re su h a te was diti d uidelik dat die liuidige m elode hersien moes word. (2 p Voorlopige studies is onlw crp om die optim um v la k k e in die volgende k o m p o n en te van b orskasfisioterapie vas te stel: die k o r r e k te su u rsto fk o n se n tra sie vir hiperventilasie gcdurende borskasfisioterapie: die k o r r e k te su ig in g sd n /k vir irageo- brongiale suiging vir die pasgeborene: die m ees g e sk ik te ventilasie sisteem vir die pasgeborene. (3) D ie bevindings van die voorlopige stu d ies is g e b ru ik om 'n b e te r m etode te form uleer. H ierdie m e tode is v ergelyk m et die nuwe m etode w aar 'n m eganiese vibrator g e b ru ik word. D aar is g e vind dat o o rm atige bantering van die suigeling hom blo o tste l aan aansienlike doling in t c P 0 2. IN T R O D U C T IO N T h e m a n a g e m e n t o f the n e w b o r n infant with respi rat or y distress sy n d r o m e is one o f the m o re s tr ik ing success stories o f m o d e r n pe rin a ta l care o v e r the pa st tw o dccades. The i m p r o v e d care o f the ill n e on at e is largely d u e to the advances in the u n d e r s t a n d i n g o f the aetio logy a n d pa tho ge nes is of diseases th at ch all en ge this age grou p. T h e i n t r o d u c t i o n of m echanical ve ntilatio n has also assisted in lo we rin g the m o rt a l it y rates in this age gro up. H ow ev er , the a p p lic at io n o f this has given rise to many pr ob lem s. It has been fo un d th a t the success o f mechanical ve n til at io n in this age g r o u p de p e n d s largely on the m ai n t e n a n c e o f clear airways. I n t u b a t e d n e w b o r n in fants req uire special care, inclu din g i n te n s i v e c he s t p h y s i o t h e r a p y a n d t r a c h e o b r o n c h i a l s u c tio n in g to keep the air wa ys pa te n t. A l t h o u g h the need for this for m o f t h e r a p y is well recognised, it is no w a well- d o c u m e n t e d fact th a t in the n e o n a t e chest p hy si o t h e ra p y has a side effect in the for m o f a re su lta nt st ate o f te m p o ra r y hy p o x a em i a (H ol l o w a y et al, 1966 a n d 1969; G r e g o r y , 1974; D a n g m a n et at, 1976; Fox et al, 1978; C o r a d e l l o el al, 1979 a n d S i m b r u n e r et al, 1981.) H ow ev er . H o l l o w a y et a l (1969) s ho w ed t h a t h yp e r v e n t il a ti o n in the form of i n te rm itt en t bag ve n til at io n with 100 per cent oxygen o r with an oxygen- en ric hed gas c o u ld prevent a critical d r o p in P O , du ri n g th er a p y, t her eb y mini mis ing the effect o f hypox aem ia. S u bs eq u e nt ly hy pe r v e n t il a ti o n has b e co m e a routine pr actice in in fan ts d u r i n g the receipt o f chest physio ther ap y. ‘ L ect u re r, S u b - D e p a r t m e n t of Ph y s io t h e r ap y , University o f Du rb an -W es tv ill e. Received 30 April 1982. T H E P U R P O S E O F T H IS ST U D Y This st ud y was u n d e r ta k e n to e va lu at e every c o m p o n e n t o f chest p h y s io th er a py as app lie d to the n e o n a t e at King E d w a r d VIII H o s p ita l in D u r b a n (Sou th Africa). This was d on e with the i n te nt io n o f isolating the cause o f hyp oxaemia. M E T H O D P a tie n t population A total o f 134 p a ti e nt s were used in this study. Th ey w er ^ all in fants u n d e r the age o f o n e m o n th . F o r t y five w e r ^ d ia gn os ed as n e on at al r e sp ir at or y distress s yn d ro m e . 86 as t e t a n u s n e o n a t o r u m a n d 3 as p ost -o pe rat ive re spiratory co mp li cat io ns . M e a su rin g Index It is now widely a cce pt ed th a t the m e a su r e m e n t o f bl ood gases is one o f the mo st reliable m et h o d s o f assessing r e sp i r at o ry fu nc tion. In these studies t r a n s c u t a n e o u s oxygen m o n i t o r i n g was use d to assess the effect o f th era py. This is a non- inv as ive m e t h o d a n d has p r o v e d very reliable in the n e o n a t a l age gro up . C H E S T P H Y S IO T H E R A P Y T hi s co nsisted of; • I n t e rm i tt e n t Positive Pressure M a n u a l Ventilation ( I .P .P .M .V .) with the aid o f a locally m ad e mini ru bb er bag. • M a n u a l v i b ra ti on s ap p lie d to the chest. • T r a c h e o b r o n c h i a l suctioning. R ep ro du ce d by S ab in et G at ew ay u nd er li ce nc e gr an te d by th e P ub lis he r (d at ed 2 01 3. ) physiotherapy, Ju n e 1982, vol 38, no 2 29 t h e s t u d i e s Nine studies were c o n d u c t e d over a p e r io d o f six mo nth s. These were divide d into 3 categories: • As sessment studies • Preliminary studies • Final study The assessm ent stu d ies were desi gne d to investigate the effect of the ex isting m e t h o d o f chest p h y s i o t h e r a p y on t r an s cu t an e o us oxygen tension ( t c P 0 2). One o f the assess men t studies in vestigating the co m b i n e d effect o f chest p h y s i o t h e r a p y a n d s u c tio ni ng sh o w ed th at this form of th e r a p y c au s ed a fall in t cP O , in every infa nt used in the trial. T h e m ean fall was 37 m m H g in the 13 infants studied. T h e fall in tcP O, laste d up to 45 min ut es b e f o r e p r e ­ phy si ot her ap y levels were achieved. On ex am in in g the results o f all the assess men t studies it was clear that there was a ne ed for revision in the existing meth od o f chest ph y si o th er a py . The prelim inary studies were de signed to provide i n f o r m a t io n r e ga r di ng the o p t i m u m a n d safe levels in the various c o m p o n e n t s o f n e o n a t a l chest p h y si ot he r a p y . F o r example, one st u dy was p l a n n e d to investigate the rou tine use o f 100 per cent oxygen d u r i n g chest ph y si o th er a p y . The results o f this stu dy in dicated that it was totally unne cessary to expose every infan t to 100 per cent oxygen du ri n g ph ysi otherapy. T h is was highly significant because the da ngers o f oxygen toxicity is a very real pr o b lem . It was now possible to pr ovide so m e guidelines as to the percentage of oxygen r e q u ire m e n t in every infan t requiring therapy. Only those infants with re sting tc P O , below 100 m m H g requ ire d 100 p er cent oxyge n whereas infants with tePO, levels over 120 m m H g c ou ld easily be m a n a g e d with 60 per cent oxygen d u r i n g thera py . An o t h e r pre lim in a ry stu dy was desi gn ed to d e te rm in e the safe suc tio n pressures that c o ul d be app lie d t o the neo nat al airways. Three p r e ss ur e levels were tested, -350 m m H g , -250 m m H g, -150 m m H g . It was fo u nd th at there was considerable di st u r b an c e in o x yg e n at io n a n d that the hypoxa emi a c ou ld not be reversed even with 100 p e r c e n t oxygen il the negative suc tio n pressure was not regulated within safe levels. High su c tio n pressures ( o v e r - 1 5 0 m m H g ) caused a m a r k e d d r o p in tcP O. On the basis of resulting tcPO_, changes, a suc tio n pr ess ur e o f not more th an -155 m m H g was r e c o m m e n d e d when suc tio n in g neonatal |iirways. The last set o f p re li m in a r y studies were pl an n e d to d e te r m i n e the most effective m a n u a l b a g ve nt il at io n system for the neo nat e. In this st u d y 3 bags were c o m p a r e d : • T h e co n v en ti o n al locally m a d e mini bag, the size o f a toy ba lloon. • T h e S a m s o n N e o n at a ! Re su sc ita tio n Bag. • T h e Pa ed iat ric A m b u Bag. T w o i m p o r t a n t f e a t u r e s we re c o n s i d e r e d w h e n d e t e r m i n i n g the most suit able b a g ve nt il at io n system, th a t is, the i n sp i r at o r y pressu res g en era ted by the system a n d the t c P 0 2 levels achieved. T h e Pae diat ric A m b u Bag p r o v e d to be the safest when the ab o v e fa cto rs were considered. T he o u t c o m e o f the p r e li m in a r y studies was a d r a st ic revision in the existing m e t h o d o f chest p h y s i o t h e r a p y as ap pli ed to the n e o n a t e with r e sp ir at o r y d is tr e ss . T h e findings p r o v id ed the m u c h - n e e d e d in f o r m a t io n to f o r m u la t e a well- g r a d e d m e t h o d o f chest p h y s i o t h e r a p y which was best suited for the mec hanic ally ven tilated ne onate. W h en the efficacy o f this u p g r a d e d m e t h o d was tested it was f o u n d th at it was still no t possible t o e r ad ic a te the incidence o f hy p o x a em i a. Nevertheless the d r o p in t cP O , resulting f r o m the u p g r a d e d m e t h o d was far sm aller t h a n the fall in tc P O , res ulting f r om the c o nv en ti o na l m ethod. The c o m b i n e d effect o f chest p hy si o t h e r a p y a n d su ct io n in g resulting f r o m the u p g r a d e d m e t h o d c aus ed a mean fall o f 16 m m H g in a st u dy which involved 21 infants. T H E FIN AL ST U D Y This was a c o m p a r a t i v e stud y to investigate t cP O , changes b r o ug h t a b o u t by two different m e t h o d s o f chest p h y s io th er a p y in the neo nat e. T w e n ty - o ne mechanically ventilated infants were stud ied , diagno se s as sh o w n in T abl e I. M ethod ‘A ’ T his co nsi ste d o f a r o ut in e clinical assess men t c arr ied ou t for each infan t p r i o r to therapy. Only those wh o were clinically stable were used for the study. T c P O , was m on it o r e d d u r in g the co u rse o f the entire stu dy with m e a s u r e m e n t s b e i n g r e c o r d e d b e f o r e a n d a f t e r phy si ot her ap y. T he p r e - t h e r a p y m e a s u r e m e n t was mad e while the in fant was at rest. Su b s eq ue n tly the infant was t r ans fer re d to the m an u a l ve nti lat io n system usi ng the Mini A m b u Bag. T h e cot was then tilted to effect d r a in a g e o f the affected ar eas o f the lung. This was followed bv m anu al v ib rat io ns o n the chest a lt e r n a t e d with bag ventilation. After T A B L E I D I A G N O S I S O F P A T I E N T S D iagnosis P aralysed W ith o u t Paralysis T otal N u m b e r Severe Neo nat al T et an u s II g l 9 Neonatal Re spi rat or y Distress S y n d r o m e I I Ne onatal Post-O per at ive Co m p li c at i o n 1 I C O M P A R I S O N O F M E T H O D A A N D B: P R E - A N D P O S T - P H Y S I O T H E R A P Y t c P O , ( M E A N A N D S D V M E A N ------ ---------------O F T H E D I F F E R E N C E S O F t c P O , A N D S T A B I L I S A T I O N T I M E ( M E A N A N D S.D.)________ M a n n -W h itn e y l n ‘!lees M e th o d A M e th o d B P Value U -Test ‘T Value Pn , p ^ S1 ! r ap y t c P ° 2