Respiratory distress following elective repeat cesarean section

FETUS,PLACENTA, ANDNEWBORN

Respiratory distress following elective repeat cesarean section RICHARD

L.

DENNIS

C.

WILBUR

L.

j.4MES

A.

,4LAN

M.

LILLIE

M.D. M.D.

SMITH,

M.D.

LEMONS.

M.D.

GOLICHOWSKI,

M.

Indirtnnpoli~.

SCHREINER, STE\‘ENS,

M.D.

PADILLA,

M.D.

Indiclrw

The clinical course and chest radiographs of 47 infants with respiratory distress after elective cesarean section were reviewed. The mean difference between the gestational age determined prenatally and that postnatally was 2.6 2 1.6 weeks. However, 14 of the infants were delivered at term. All 47 infants required more than 40% oxygen, and 18 infants required a respirator. Fifteen infants developed a pneumothorax; one, a pneumopericardium; one, bronchopulmonary dysplasia; and one infant died. Chest radiographs and the clinical course were consistent with hyaline membrane disease in 17 patients; respiratory distress syndrome type II in 24; and in three the radiographic findings were normal. These data suggest that some of the respiratory morbidity subsequent to elective repeat cesarean section is not secondary to iatrogenic delivery of a premature infant, and that much of it is not due to hyaline membrane disease. These data emphasize that respiratory distress in an infant delivered by elective cesarean section does not necessarily suggest poor prenatal care in regard to the timing of delivery. (AM. J. OBSTET. GYNECOL. 143:889, 1982.)

management of’ the high-risk pregnancy has resulted in an increased incidence of primary cesarean section. After a primary cesarean section, elective repeat cesarean section is of’ten the MODERN

OBSTETRIC

From the Departments of Pediatrics, Gynecology, and Radiology, Indiana Medicine, and the James Whitcomb Children. RecPi~~pd

jarpublication

Accrptud

March

Octob(zr

Obstetrics and Unizvrsity. School Riley Hmp~talfor

26.

1981.

2, 1982.

R+-znt requests: Richard L. Schreiner, M.D., Departmrnt of Prdiatriw, Indiana Unizwsity School of Medicine, I1 00 West Michigan St., Indianapolis, Indiana 46223. 0002-9378/82/140689+01$00.40/O

0

1982 The

C. V. Mosby

Co.

of

method of‘ delivery utilized in subsequent pregnancies. Because of the above-mentioned two practices, the number of’ elective repeat cesarean sections has increased, also, over the past decade.‘-” The underlying reason for the increased incidence of primary cesarean sections has been to improve the rate of tetal and neonatal morbidity and mortality. Ho\\,ever, the increased incidence of primary cesarean section has resulted in an increased risk to the mother from each subsequent cesarean section, as well as the risk of delivering a premature infant in each of the subsequent pregnancies bvhen elective repeat cesarean section is the method of‘ delivery. Numerous investigators have demonstrated signiti689

690

Schreiner et al

Table I. Difference newborn estimation

between obstetric and of‘ gestational age

Table II. Morbidity associated cesarean section in 47 patients

with elective

repeat

.c’o. of //rr/ir,,f.\ Prematurit\ (C37 wk) Asphyxia Apgar score C.5 at i Inin Apgar score <7 at .5 mill Respirator\ distress: HMD KDS

‘j.-Cl

6 1-x0’/; >xw Oxygen requirement >-WQ: I-25 111. “ti-.N Ill5 l-i,? t1r 76-100 I1r 101-L’oo hr >L’oo 111 (:l’Al’ Kespirator Pneumothorax Pneumopericarciiunl Bronx-hopufmon;~r~ dysplasia Died

7 35 IO 7 $1 II 7 :< 30 IX I.‘, I I I

Results

cant morbidity and a few instances of mortality in infants with respiratory distress subsequent to elective cesarean section. A review of these articles indicates that most authors believe that most of‘ the respirator) distress subsequent to elective ccsarean section is due to hyaline membrane disease (HMD) secondary to iatrogenie delivery of a premature infant.‘+!’ These studies have been widely quoted in medicolegal discussions, with the implication that serious respiratory distress in an infant delivered by elective cesarean section without labor suggests poor prenatal care. In the present article, we examine the etiology of respiratory distress in a large series of infants with this condition subsequent to elective repeat cesarean section. Material

and methods

The 2,080 admissions during a Y&month the James Whitcomb Riley Hospital Newborn

Care Unit were reviewed. Excluded was any patient who uas delivered by repeat cesarean section pet.formed for medical reasons, including premature labor or rupture of’membranes. .41l pregnancies complicated by diabetes or Rh incompatibility were excluded. Patients i\,ho were admitted for nonrespirarory problems infection) !\‘erc rxcluded. An (congenital anomalies, evaluation ~2;~smade of the obstetric estimate of’ gcst;ltional age. estimated date of confinement (EDC). tests fi)r fetal maturity, birth \\eight, l- and 5-minute Apga~ scores. esrimatecl gestational age (EGA) by the neonatologi.st (Dubowit/ examination),” maximum percentage of oxygen required 1,) the patient to maintain the arterial PO, at 50 to X0 111111Hg, number of’ hours of requirement f’oi- more than -IO% ox)~gen. number ot hours on continuous positive airway pressure (CPAP), number ot hours on respirator, other diagnoses, (omplications. culture results, and radiographs. The s-l-a!’ til~m for three of’ the patients could not be located. ~I‘hr clinical COUIW a~ltl cheat radiographs were re\.ieweti indcpendentl~ by ;I neonatologist md a pcdiarric racliologixt. ‘4 diagrlosis of. HhlD \I;IS nlade on the basis ot ;I I\ l)ical radiographic l)a~tc’l-r~ \virh ditf’use granular itifilu-area :i~ld air 1~1~o~i~l1o~r;~~i~s,and ihc. requiretrienl of niorc’ than 40’4 ox)geil li)r 72 hours oi more. Tlic diagnosis 01 respirator\ distress s) ntli~mic (RDS) I)~IC II \\‘a~ m~tlc~ h the lmwnce of wc.alq vascular dcnsitics, Ioc-ali/cci infiltrates \\ith regional distribution. and/or fluid in the pleural fissure. Pcrsistenr fetal circulatioil (PF<:) was diagnosed on the basis of respiratory distress and rccluiremcnt for oxygen \vith normal findings on the c.hesr radiograph.

period to Intensive

Forty-se\.en paGents were hospitalized because of‘respiratory clisu-ess after elective repeat c‘esarean section. The mean birth weight ot’the patients was 2,930 2 506 (SD) (range. 2,090 to ‘1.082) gm. The obstetric estimate of‘ the gestational age was Xl.5 i I .I! (range, 36 to 40) weeks, whereas the mean gestational age by the nclvborn examination was 36.5 ? 1.3 (range. 34 to -10) weeks. The dif’f’erence in gestational age between the obstetric and ne\vborn examinations (Table 1) was 2 weeks or less in IG 01’ the paticnth. 3 \t,erks in eight patients, and l weeks or more in 2.’ patients. In onh one case lvas the obstetric estimare of the gestational age less than the neonatal cstimatc. The mean difference in tlie gestational age determined prenatally and postnatally was 2.6 t 1.6 weeks (p < 0.001). In three mothers, an amniocentesis was attempted, but in only one was it successful, anti a lecithin/ sphingomyelin (L/S) ratio was not obtained (crearinine only). Ultrasound examination was perf’ormed in eight

Respiratory

mothers for determination of fetal maturity, but it was a single evaluation done less than 5 weeks before delivery in seven cases. The diagnosis and clinical course in the 47 patients are presented in Table II. All 47 patients required more than 40% oxygen during their hospitalization. The mean maximum oxygen concentration required bvas 90% (range 50 to 100%). The mean number of hours per patient ot‘ requirement for more than 40% oxygen was 73 ? 52 (range, 1 to 320) hours. If the three patients w,ho required more than 40’3 oxygen for more than 200 hours are excluded, the mean is 62 t 36 (range, 1 to 152) hours. Thirty patients required CPAP for a mean 01‘47 * 26 (range 7 to 112) hours. Eighteen of the 47 patients required intermittent positive pressure ventilation for a mean of 64 2 37.-l (range, 5 to 13 1) hours. Pneumothorax \ras a common complication in these patients: tight of‘the 18 infants (44%) lvho required a respirator and seven of’ the 29 (24%) \vho did not require a respirator developed a pneumothorax. .4 spontaneous pneumopericardium occurred in one infant who required neither CPAP nor a respirator. One infant de\-eloped bronchopulmonary dysplasia, and one infant died at 26 hours of age with bilateral pneumothoraces. Analysis of the chest x-ray films and the clinical course she\\-ed that only 17 intants had HMD; 24 had RDS type II; and three had PFC. S-ray films were not available for three patients. Blood cultures performed in 42 patients were all negative. Five infants did not have a blood culture and \yere not treated with antibiotics. Cultures of tracheal aspirate were not performed. Fourteen of’the 47 infants Ivere estimated to be more than or equal to :18 weeks’ gestational age by both obstetric and pediatric examinations. Six of these 1-l term infants had a clinical course and radiograph consistent with HMD. Of the 18 intants who required intermittent positive pressure ventilation, only eight had HMD, eight had RDS type II, and in tlvo cases the x-ray tihns were not available. The 47 patients remained in the Newborn Intensive Care Unit fi)r 12 2 22 (range, 1 to 156) days. One patient required hospitalization for 156 days because of bronchopulmonary dysplasia. If this patient is excluded, the mean number of days of hospitalization is 9.2 -+ 4.4 (range, 1 to 19) days. However, 18 patients were transferred back to their local hospital. Theretore, these data underestimate the duration and cost of hospitalization.

Comment Data in this study confirm nificant respiratory morbidity

previous reports of sigassociated with elective

distress

following

cesarean

section

691

repeat cesarean sectiona-” and suggest that such morbidity is secondary to a number of disorders, including HMD, RDS type II, and PFC. Sixty percent of the patients with respiratory distress in this study, including 55%’ of those with severe distress that required respirator support, did not have HMD. In addition, 30% of the infants in this study lvere diagnosed as being more than or equal to 38 weeks’ gestation by menstrual history and both obstetric and pediatric examinations. Since the completion of this study, we have admitted to hospital eight infants 36 to 40 weeks’ gestational age. all of whom had mature L/S ratios (eight different laboratories), \vho had severe respiratory distress that required ventilator support \vith an x-ray and clinical picture compatible with PFC. Numerous in\,estigators in the past have argued that many cases of respiratory distress in the nelvborn infant are not secondary to a deficiency of surtactant. Some of the proposed etiologies include aspiration of clear amniotic fluid”. ” aspiration of bloody amniotic fluid,” and delayed resorption of fetal lung fluid.“’ These disorders have been termed wet lung syndrome, transient tachypnea of the newborn, RDS type 11, amniotic fluid aspiration, and aspiration syndrome of the newborn. Since none ot. the intants in this study had meconium-stained amniotic liuid, this etiology can be excluded. Some in\.estigators describe transient tachypnea of the ne\\.born, \vet lung, or respiratory distress syndrome type II as a benign form of respiratory distress that resolves lvithin 24 hours with appropriate oxygen and supporti\,e therapy but does not require a respirator. However, as seen in this study. infants with normal findings on chest x-ray films or with radiographic diagnoses compatible lvith RDS type II ma)have severe respiratory distress that requires \.entilator support and have a high incidence of complications, including pneumott~oras. \\‘e believe that many of these patients Mith respiratory distress subsequent to elective cesarean section, including some of our patients with a diagnosis of RDS type Il. have a clinical picture compatible l\,ith PFC. Although the chest radiographic findings \vere normal in only three patients. the clinical picture of severe respiratory distress with minimal infiltrates in many of the other patients with a diagnosis of RDS type II suggests PFC. Leder and absociates’” have recently reported that 15% of’ their patients with PFC were delivered after elective ccsarean section. Although the clinical picture of many of these infants is compatible with pneumonia, the lack of rupture of membranes and the negative blood cultures suggest that pneumonia was not a frequent etiology ot respiratory distress in these infants. A recent study by Callen and associates’” suggests

692

Schreiner

et al.

labor results in a release of fetal lung surfactant into the airways. This might explain the HMD in some (especially term) infants after elective cesarean section. Milner and associates’” have recently demonstrated increased retention of fluid in infants after cesarean section. A prospective study to determine the effect of that

labor

on

the

incidence

and

severity

of respiratory

dis-

tress subsequent to elective cesarean section would demonstrate whether iatrogenic prematurity or the mode of delivery (cesarean section versus vaginal) is the most important determinant of the respiratory distress. Regardless of the primary factor, much of the respiratory distress associated with elective cesarean section, especially elective repeat cesarean section, might be prevented if the mother were allowed to begin labor spontaneously before the cesarean section was performed. In addition, there is a renewed interest in the possibility that some, or many, women may be deliv-

ered vaginally after a previous cesarean section.“‘, li The presence of severe respiratory distress after elective cesarean section has, in many cases, resulted in malpractice claims. A review of previous reports on respiratory distress in infants delivered by elective cesarean sectior?’ suggests that most such cases are a result of poor prenatal care related to the timing of the delivery. However, our retrospective study demonstrates that many of these infants are, in fact, not premature. In addition, much of the respiratory distress is not secondary to HMD: it is likely that the respirator) distress in these infants is secondary to the mode of delivery, not the delivery of a premature infant. Thus, the data in this study demonstrate that many, in fact, most, cases of respiratory distress subsequent to elective cesarean section are not suggestive of poor prenatal care and, therefore, not examples of medical negligence.

REFERENCES 1. Hibbard, L. T.: Changing trends in cesarean section, AM. J. OBSTET. GYNECOL. 125:798, 1976. 2. Jones, 0. H.: Cesarean section in present-day obstetrics, AM. J. OBSTET. GYNECOL. 126:521, 1976. 3. Sutherst, J. R., and Case, B. D.: Caesarean section and its place in the active approach to delivery, Clin. Obstet. Gynaecol. 2:241, 1975. 4. Cowett, R., and Oh, W.: Foam stability predictions of respiratory distress in infants delivered by repeat elective cesarean section, N. Engl. J. Med. 295:1222, 1976. 5. Evrard. J., and Gold, E.: Cesarean section: Risk/benefit, Perinatal Care 2:4. 1978. 6. Flaksman, R. J., Vollman, J. H., and Benfield, D. G.: latrogenic prematurity due to elective termination of the uncomplicated pregnancy: A major perinatal health care problem, AM. J. OBSTET. GYNECOL. 132:885, 1978. Goldenberg. R., and Nelson, K.: Iatrogenic respiratory distress syndrome, an analysis of obstetric events preceding delivery of infants who develop respiratory distress syndrome, AM. J. OBSTET. GYNECOL. 123:617. 1975. Hack, M., Fanaroff, A., Klaus, M., et al.: Neonatal respiratory distress following elective delivery. A preventable disease? AM. J. OBSTET. GYNECOL. 126:43 1976. Maisels, M. J., Rees, R., Marks, K., et al.: Elective delivery of the term fetus, an obstetrical hazard, JAMA 238:2036, 1977.

10.

Dubowiw L.. Dubowitl. V.. and Goldbew. C.: Clinical assessment of gestational age in the newb&-n infant, J. Pediatr. 77: 1, 1970. 11. Klein. M.: Asphyxia neonatorum caused by foaming, Lancet 1:1089, 1972. 12. Pender, C.: Respiratory distress in the newborn infant due to blood aspiration in infants delivered by cesarean section, AM. J. OBSTET. GYNECOL. 106:711, 1970. 13. Milner, A., Saunders, R., and Hopkins, I.: Effects of delivery by caesarean section on lung mechanics and lung volume m the human neonate, Arch. Dis. Child. 53:545, 1978. 14. Leder. M. E., Hirschfeld, S., and Fanaroff. A.: Persistent fetal circulation: An epidemiologic study, Pediatr. Res. 14:490, 1980. 15. Callen. P., Goldsworthy, S., Graves, L., et al.: Mode of delivery and the lecithin/sphingomyelin ratio, Br. J. Obstet. Gynaecol. 86:965, 1979. 16. Merrill. B. S.. and Gibbs, C. E.: Planned vaginal delivery following cesarean section, Obstet. Gynecol. 52:50. 1978. 17. Morewood, G. A., O’Sullivan, M. J., and McConney, J.: Vaginal delivery after cesarean section, Obstet. Gynecol. 42:589, 1973.