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166 INDIAN PEDIATRICS VO LUME 34 FEBRU

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					INDIAN PEDIATRICS                                                     VO LUME 34 - FEBRU AR Y 1997



       Selected Summaries


Partial Liquid Ventilation in                      cheal tube during momentary discon nec-
Neonates                                           tion from the ventilator . The volume of liq-
                                                   uid thus required represented the infant' s
                                                   functional residual capacity (FRC). Ten in-
[Leach CL, Greenspan JS, Rubenstein SD, et al.     fants received PLV for 42±5 h (range 24-
Partial liquid ventilation with perflubron in      76h). Three infants who had received high
premature infants with severe respirator]/ dis-    frequency ventilation prior to enrollment
tress syndrome. N Ehgl J Med 1996; 335: 761-       were withdrawn from the trial within four
767]                                               hour s du e to continued refractory
                                                   hyperc apnia and were pu t back on high
     Experim enta l evid ence has sug gested       frequency ventilation. The initial volume of
that instillation of perfluorocarb on liquid       perflu bron instilled was 15±4 ml/kg. With -
into the lungs during cont inuous positive         in one hour of instillat ion of perflubron,
pressu re gas ventila tion [partial liquid ven -   theart erial PaO 2 rose from a bas eline of
tilation (PLV)] improves lung function in          60±34 mmHg to 143±99 mmHg (p=.O2), the
animals with surfactan t defic iency( l). The      dynamic compl ianc e from 0.18± 0.12 ml/
present uncontrolled clinica l trial assessed      cm H2O/kg to 0.29±0.12 ml/cm H2O/kg.
the efficacy of PLV in 13 premature infants        During the first 24 h there was a significant
(gestationa l age, 24 to 34 we eks ; birth         reduction in oxygen index and mean air -
weight, 600 to 2000 g) with severe respira -       way pressure, arterial pCO 2 value and an
tory dis tress syndrome who were less than         increas e in tidal volume. In most infant s
5 da ys old and were considered to have a          chest skiagrams revealed scant traces of
high risk of death on the basis of lack of         perflubr on 48 h after return to gas venti la-
sust ained respons e to surf actan t ther ap y     tion. No adverse effects clearly attributable
and the cont inued requirem ent for a high         to PLV were observ ed. Inf ants were
level of supplemental oxygen and ventila -         weaned from PLV without complications.
tor support. All 13 infants had PaO 2 values       Eight of 10 infants survived.
< 60 mm Hg or PaCO 2 > 60 mm Hg on two             Comments
consecutiv e determ inations and required
oxygen therapy with a fra ction of inspired            Perfluorocarbon liquids have low sur -
oxygen of 1.0 and a mean airway pressure           face tension and high density and at atmo-
of more than 10, 12 and 14 cm wat er for           spheric pressure large amount of oxygen
birth weights 600 to 1000 g, 1001 to 1500 g        and carbon dioxide dissolve in them. Re-
and 1501 to 2000 g, respectively. PLV was          placement of the gas functional residual ca-
initiated by instilling perflub ron at a rate of   pacity by perfluorocarbon liquid eliminates
1 ml per kilogram of body weight pe r              the alveolar membrane air liquid interface,
minut e, through the side port of endotr a-        reduces surface tension in the surfac tant
cheal tube without interrupting mechanica l        deficient lung and physica lly keep s the al-
gas ventil ation, maintaining a posit ive and      veoli opn(2). Perflubron is not absorbed
exp iratory pressure of 4 cm of water unt il       from the lungs into the system ic circul a-
a column of fluid welted u p in the en dotra -     tion. Further, perflubron is not inact ivated

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INDIAN PEDIATRICS                                                          VOLUME 34 - FEBRUARY 1 997


by protein an d thus will reduce sur face ten -      technique. While PLV may appear a prom-
sion in a proteinaceous alveolar environ-            ising alternative to avai lable ventil atory
ment less responsive to surfactant. This is          modalites, it is still to be considere d inves-
perhaps the reason why the infants in the            tigational and one w ould have to a wait the
present s tudy did not respond to surfac tant        result of more ran domized trials.
therapy and PLV may prove an effective al-
                                                                                    K. R ajesh wari,
ternat ive.
                                                                            Department of Pediatrics,
    However, several questions still rema in                                    Hindu R ao Hosp ital,
unanswered . The discontinuation of PLV                                              Delhi 110 007.
after 24 to 72 hou rs leaves the optimum d u-
ration for part ial liquid vent ilation unan -       REFERENCES
swered. All the infants had received prior            1.   Gree nspan JS, Welfson MR, Rube nstein
surfactant therapy and the possible benefits               SD, Shaffer TH. Liquid ventilation o f hu-
of PLV as an alternative to surfactant thera-              man preterm neo nates. J P ediatr 1990 ;
py rema in unkn own, as also it's ab ility to              117:106-111.
prevent chronic lung dis ease in pret erms
                                                      2.   Hirschl RB, Pranikoff T, Ganger P,
ventila ted for RDS. The unco ntrolled de-                 Schreiner RJ, Dechert R, Bartlett RH. Liq-
sign and small sample size precludes at the                uid ventilation in adults, childr en and full
present drawi ng firm conclusions on the ef-               term neonat es. Lancet 1995; 346: 1201 -
ficacy and safety o f this n ew v en tilatory              1202.




Withdrawal of Antiepileptic Drugs                    ed details of seizures and neuro-develop -
After One Year?                                      ment status of child. Medica tion was dis-
                                                     continued gradually over 4 to 6 weeks. Be-
                                                     fore discontinuation of drug, every patient
                                                     had electroencephalography (EEG); how -
[Dooley J, Gordon K, Camfield P, Camfield C,
Smith E. Discontinu ation of antico nvulsan t
                                                     ever, results of EEG did not influence the
                                                     decision to withdr aw. Th e pr imary end
therapy in children free of seizures for 1 year: A
prospective study. Neurology 1996; 46: 969-
                                                     point of the study was the recurre nce of a
                                                     clinical seizure. All children were followed
974]
                                                     at 6,12,18 and 20 months after AED with-
                                                     drawal, or a seizure relapse occur red.
    In an attemp t to study wh ether
anticonvulsant can be withdraw n after one               Out of total 97 patients, 50 were boys
year of seizure free period, authors includ-         and 47 were girls. The age at seizure onset
ed 97 children wh o had two or mor e                 was from 1 to 198 months (mean 65.9±43.89
afebril e seizures, and subsequently wer e           month). The mean age at attaining seizure
seizure free fo r 12 to 13 mon ths on                control (date of last seizure) was 86.95 ±49.2
antiepi leptic drug (AED) monotherapy. At            months . The patients were followed for 12
the time of inclusion, all patients were sub-        to 57 months (32.4±13.1 months), or until
jected to de tailed neurologica l his tory and       seizure recurre nce. The overall probability
exam ination. Info rmation recorded includ -         of remaining seizure free was 78% at 3
                                                                                                    16 7
SELECTED SUMMARIES


mon ths, 71% at 6 mon ths, 66% at 12               withdrawn are those who have had no se i-
months , and 61% at 24 months. Four im -           zures for a long period, those who had few
portant factors were noted to be important         seizures before control was achi eved, and
for predicting seizure recurrence ; Thes e         those with a nor mal neurological examina -
factors were female sex, age at seizure on -       tion and no structural brain lesion(4). The
set over 120 mon ths, seizure type, and clin-      observations of present study also suggest
ical ev idenc e of neurolog ical abnorma li-       that in these similar groups of patients, the
ties. Of those over age 10 years, 72% had          withdrawal of antiep ileptic drugs may be
further seizures, wh ereas on ly 33% of            considere d even after 1 year of seizure free
youn ger ch ildr en had recu rren ces. Girls       period . Consideration of the earliest with-
did less well than boys. Patients with 'non -      drawal is worthwhile because of the poten-
rolandi c' par tial seizures did poorl y when      tial of antiepileptic drugs to adversely af -
                                                   fect co gnition and beh av ior in ch ildr en
compared with ch ildren who had genera l-
                                                   who are already at risk for disability.
ized seizures. Authors concluded that
treatment for only 1 year after last seizure           Another important issue of withdrawal
is sufficient f or many child ren with a recu r-   of antiepileptic medicat ions is the optimal
rence risk sim ilar to studi es that have re-      regimen for tapering of antiepileptic medi -
quired 2 or more years befo re withdrawa l         cations in children with epilepsy. Recom -
was attempted. It is possible to select the        mendations for tapering the antiepi leptic
children who are at least risk and to identi-      dru gs h ave r an ged from ab rup t
fy thos e whos e ch anc e of recur ren ce is       discontinuation of therapy to gradual ta-
high-Commen ts                                     pering over a period of two years. In most
                                                   studies, the taper per iod was thre e to six
    In patien ts with ep ilepsy who have           months reflecting the usual practice in vari -
been seizure free for sometime while taking        ous epilepsy centers. A recent study(5) ob-
antiepileptic medicat ions, the question of        served that the risk of seizure recurrence
'when to discontinue medi cations' invari -        du ring dru g tapering and after dis-
ably arises. There is general agreement that       continuat ion of antiepileptic drug therap y
most children who are seizure free for sev-        in children with epileps y is not different
eral years on an tiepilep tic dru g therap y       whether the medications are tapered over a
will remain so when medica tions are with -        six -week of nine -mon th pe riod. In the
dr awn (1). Ch ildr en who hav e b en ign ep i-    study under discussion, the authors have
lepsy with rolandic spikes or benign famil-        demon strated that a tap ering period of
ial neonatal convulsions usually do well af-       even 4 to 6 wee ks for child ren who have no
ter drug withdrawal whereas those with ju-         risk factors pr ed ictive of seizure recur -
venile myoclonic epilepsy often have re-           rence, is sufficient .
lapses(2,3) . Children with idiopathic gener-          However, one should be cautious while
alized seizures whether 'absence ' or 'tonic -     cons idering early withdr awa l of an ti-
clonic seizures' are least likely to have a re-    epileptic drugs in patients with clinical evi-
currence after control has been achieved           den ce of neuro logical ab nor malities.
and medication withdrawn . Even, complex           Delgado et al.(6) in a similarly designed
partia l seizures can disappear after a long       "antiepileptic drug withdrawal study" ob -
period of seizure control. The patients with       served that epileptics among pa tients of
the highes t probabil ity of rema ining sei-       cerebral pals y could also have long term
zure free after the medication has been            seizure remission. However, they needed a
16 8
INDIAN PEDIATRIC S                                                      VOLUME 34 - FEBRUARY 1 997


minimu m of two years of seizure free peri -       2.   Shinnar S, Berg AT, Moshe SL, et al. Dis-
od. In such patients of cerebral palsy spas-            continuing antiepile ptic drugs in childre n
tic hemiparesis signific antly increases the            with epilepsy: A pros pecti ve stud y. Ann
risk of relapse.                                        Neurol 1994, 35: 534-545.
    Symptomatic epileps ies are inherently         3.   Antie pile ptic drug with drawal-Haw ks or
difficult to treat and frequently seizures re-          Doves? Lancet 1991; 337:1193-1194.
cur on attempt ed withdraw al of drugs. In
India, singl e enhancing (rin g/disc) CT le-       4.   Chadwick D. A practical guide for discon-
sions are the commonest cause of epilepsy               tinui ng antiepileptic dru gs. CN S Dru gs
                                                        1994, 2: 423-428.
in children and adoles cents. In such case s
seizures are easily controllable as CT le-
                                                   5.   Tennison M, Greenwood R, Lewis D,
sion s usu ally disapp ear in 12-20 we ek s             Thorn M. Discontinuati on of antiepileptic
time. There is feeling from different Indian            drug s in children with epile psy: A com -
Neurological Centers(7,8) that a short term             pariso n of a six week and a nine mo nth
(6 months to 1 year) an tiepileptic dru g               taper perio d. N Engl J Med 1994 , 330 :
therapy is suffici ent for long term rem is-            1407-1410.
sion of seizures. However, there is need to
study the long term course of epileps y in         6.   Del gado MR, Ri ela AR, Mills J, Pit t A,
these patients before recommending short                Browne R. Discontinuation of anti-
course of antiepileptic treatment.                      epileptic drug treatment after two sei -
                                                        zure-free years in children wit h cerebral
                          Ravind ra Kr. Garg,           palsy. Pediatrics 1996, 97:192-197.
                     Department of Neur ology,
                 King George's Medical College,    7.   Shrini vas HV. Disa ppearing CT lesions -
                             Lucknow 226 003.           Clinical features. J Trop Geograph Neu rol
                                                        1992, 2: 88-91.
REFERENCES                                         8.   Sawhney IMS, Lai V. Single seizure: To
 1. Berg AT, Shinnar S. Relaps e follow ing             treat or not to treat? In: Reviews of Neu -
     discontinuation of anti epile ptic drugs: A        rology, Vol 3. Ed. Murth y. JMK
     meta analysis. Neurology 1994, 44: 601-            Hyderabad, Indian Academy of Neu ro -
     608.                                               logy 1996, pp 65-75.




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