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Volume Uie} Number I, Part 2

COMPARISON OF VISUAL AND AUTOMATED ANALYSES OF RESTING FETAL HEART RATE. L.D. Devoe, A.K. Hiett,"'J.B. Bartelsmeyer~ Dcpts of Ob­Gyn, Medical College of Georgia and Washington University School of Medicine, Augusta, GA and St. Louis, MO

The Oxford Sonicaid System 8000 provides computerized archiving and analysis of resting fetal heart rate (FHR) records. We compared System 8000 wIlh visual analysis (V A) of nonstress tests, performed between 32 and 42 weeks and < 7 days of delivery, in 500 high nsk pregnancies for test rating, Influence on management strategy, and outcome predictIOn. VA used a reactIvity criterion of ;::2 acceleratIOns >15 hpm In 20', System 8000 used a mean variation critenon of > 30 msec. Management strategy was based only on V A interpretations. ReView of System 8000 records and strategy selection were retrospective and blinded to V A and delivery outcome. V A and System 8000 had SimIlar sensitivity «50%), ;pecificity (97%), negative predictive value (99%), and positive predictIve values «50%). Cramer's statistics for both methods were 0.30 (test rating) and 0.13 (strategy selection). CONCLUSION: System 8000 provides diagnostic accuracy comparable to that of V A; thiS IS achieved with a considerably different rating scheme. The differences in strategy which might have been influenced by System 8000 would not have been clinically important.

SUBCUTANEOUS TERBUTALINE TOCOLYSIS FOR RECURRENT PRETERM LABOR VIA INFUSION PUMP, JR AllbertX , C Johnsonx , WE Roberts, RW Martin, KS Gookinx, JC Morrison, University of Mississippi Medical Center, Jackson, MS.

Subcutaneous pump admi ni strati on (P) of terbutali ne (T) at basal rates and 4-6 boluses per day has been suggested in patients with recurrent preterm labor. An automated, programmable MiniMed infusion pump and home nursing care (Tokos Med. Corp., Santa Ana, CAl were ut l1i zed in 32 subj ects. Pat i ents tak i ng ora 1 beta-agoni st (0) were matched for age, race, parity, gestational age, cervical dilatation at recurrent labor as a control group (n=32). Patients received a mean basal rate of 0.086 mg/hr and 6.5 + 1.6 boluses (0.248 mg/bolus) of T per day. In P sutiJects, the rate was adjusted to < 4 contractions/hr as judged by the home contraction monitoring. 0 subjects were maintained on beta-mimetics at 2.5 to 7.5 mg every 4-6 hours to maintain uterine quiescence.

Weeks Term Gr~up N Treatment Del~lery

32 4.71 o 32 3.14 5

PPI ~ ratio between actual rolon ation 37 weeks

Pregnancy Prolongation

Index (PPI) .86 .72

pro 1 ongat ion

% Falled Tocolytics

or ROM 13 38

and desired

a en s were more 1 e y 0 reac erm p had a longer PI (p < .03) compared with 0 subjects. o parturients were more likely to fail tocolytic therapy or have rupture of membranes (ROM) leading to preterm delivery more often (p < .03) and had fewer weeks on therapy (p < .03) compared to P patients. Conclusions: The administration of terbutaline by P along with intensive perinatal nurse support during home care visits and daily uterine contraction assessment allows more complete suppression of uterine activity with fewer episodes of recurrent preterm labor. When it does occur, the diagnosis is earlier and more term deliveries occur. Further stUdies with a randomized protocol appear warranted.

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SPO Abstracts 365

AMNIOTIC FLUID INDEX - GESTATIONAL AGE SPECIFIC VALUES FOR NORMAL HUMAN PREGNANCY. Hallak MX, Kirshon B, Department of OB/GYN, Baylor College of Medicine, Houston Texas

Accurate assessment of the amniotic fluid volume can guide us to fetal abnonnalities. The purpose of this study is to define normal values of Amniotic Fluid Index (AFI) in our population. One investigator prospectively measured the AFI in 892 consecutive patients. Inclusion criteria: 1. Nonnal Singleton pregnancy between 15-40 weeks. 2. Estimated fetal wei ht between lOth to 90th ercenti Ie. 3. Good datin • week mean DID 2SIJ 5th 50th 95th

15 1 7 1 1 7 16 108 30 87 109 151 44 17 113 36 96 110 151 36 18 115 50 80 112 148 49 19 126 60 84 116 167 43 20 125 34 98 120 162 51 21 120 44 87 124 168 42 22 130 42 82 124 160 41 23 122 26 97 121 158 41 24 130 88 52 121 159 27 25 120 38 40 121 164 22 26 132 92 75 121 200 29 27 125 42 63 121 185 28 28 135 60 100 122 179 22 29 135 94 34 124 226 35 30 144 76 40 140 186 29 31 135 52 90 119 180 34 32 138 98 70 120 209 47 33 147 102 93 113 238 44 34 111 48 78 114 150 36 35 136 100 90 116 180 38 36 125 94 80 112 167 41 37 108 58 80 108 161 39 38 128 92 69 108 190 26 39 112 42 66 111 164 16 40 92 28 48 91 142 12

The trend of our results is consistent with the normal values previously reported, but the absolute numbers are smaller.

CAN SUBJECTIVE ULTRASONOGRAPHIC ASSESSMENT OF AMNIOTIC FLUIil VOLUME SERVE AS A SCREENING TEST? COMPARISON BETWEEN THE SUBJECTIVE ASSESSMENT TECHNIQUE AND THE AMNIOTIC FLUID INDEX. HALLAK MX, KIRSHON B. COTTON DB. Department of DB/GYM. Baylor College of Medicine. Houston Texas

Several pathologiC situations of the fetus directly influence the amniotic fluid volume (AFV). Accurate assessment of AFV is important for detection of a compromised fetus and often alerts one to the presence of fetal abnormalities. The nonnal values for each week of gestation. for the ultrasonic four quadrant sum technique (Amniotic Fluid Index - AFI) were reported by Moore (AJOG 1990; 162: 1168). The corre lat ion between the AFI and the actua I intrauterine volume has been demonstrated in an animal model (Moore. SGI 1989). However. many obstetricians still rely on their own subjective feeling as a screening test and only if the test appears abnonnal wi 11 they perform the AFI. In this study we evaluated the abil ity of an experienced u ltrasonographer (BK) to identify abnorma I it ies in AFV by subjective assessment method in 886 consecutive ultrasound examinations. After subjective assessment of the AFV. a four quadrant AFI was done. The subject ive assessment was graded as: normal (n=815), mildly increased (n=19). mildly decreased (n=22). markedly increased (n=16). markedly decreased (n=14). The AFI was measured in mi 11 imeters and graded the same way using the 2.5th. 5th. 95th and 97.5th percentile values specific for gestational age. RESULTS: Using the subjective method we misdiagnosed 36% of abnonnal amniotic fluid volume as normal. The subjective diagnosis of mildly or markedly increased AFV was not substantiated by the AFI in 95% and 62% of the cases, respectively. The sensitivity of the subjective method for increased AFV was 100% but with a false positive rate of 74%. In 27% of the cases when we assessed mi Idly decreased AFV - the AFI was nonna 1. On ly with severe oligohydramnios was the subjective diagnosis correct in 100% of the cases. However. the sensitivity for decreased AFV was 58%. Our results suggest that subjective assessment of amniotic fluid volume is a poor screening test, and that an AFI should be part of a routine ultrasound examination.