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Reply to Dr. Crawford
CORRESPONDENCE Spinal anesthesia and ephedrine in pregnant monkeys
basis of these data, the authors concluded that ephedrine administered in the given circumstance was in any way beneficial to the fetus. J. Selwyn Crawford Consultant Anaesthetist
To the Editors: Although reluctant to raise controversy in the JouRNAL, I must protest that several of the conclusions reached by Dr. Eng and colleagues ( 115: 1095, 1973) are by no means supported by the evidence presented. It is claimed that following the administration of ephedrine to the mother who had received a spinal block the fetal arterial Po 2 and Pco 2 returned to the prespinal levels (in the Abstract this is amended to the suggestion that ephedrine prevents further deterioration of the fetus). We are not provided with the absolute figures, but my reading of the diagrams contained in the article (and I hope that the authors will correct me if I am wrong) is as follows:
Fetal Po,
Fetal Pco,
a b c d a b c
d
17
:25 38 21 25 33 45 48 40
28 10 10 37 48 54 61
The Birmingham Maternity Hospital Queen Elizabeth Medical Centre Edgbaston, Birmingham, Bl5 2TG, England
Reply to Dr. Crawford To the Editors: We want to thank Mr. Crawford for calling our attention to an error which escaped correc· tion. The sentence from our article on page 1099 should read, "As a result, uterine blood flow increased and fetal Po2 and Pco 2 returned toward prespinal levels." The absolute values upon which Figs. 1 and 2 are based are as follows:
I
20 29 12 20 38 48 49 50
Case
a A b
B c
c
These can hardly be characterized as portraying a "return to prespinal levels." Furthermore, the authors fail, in their discussion, to draw attention to the fact that, according to the mean values obtained from the 4 fetuses, the metabolic acidosis associated with the spinal block, far from being reversed by ephedrine, was actually worsened following administration of the vasopressor:
d D
pH Base excess
7.34 -2.6
Spinal
Ephedrine
7.22
7.21 -9.8
-6.3
F M
F M F M F M
I
33.8 30.2 45.2 37.2 47.5 35.8 40.0 35.5
I
37.4 25.2 49.0 32.5 55.4 30.8 61.8 32.6
38.8 22.3 49.4 30.8 49.5 33.3 49.9 34.2
Arterial Po, a
A b
B c
c
d Control
Arterial Pco, Fetal or maternal Control Spinal Ephedrine
D
F M F M F M F M
25.0 52.5 36.5 114.5 22.0 134.0 ~5.0
137.0
14.0 63.5 26.8 116.5 11.0 144.0 10.0 156.5
20.5 97.5 28.5 124.0 14.0 143.0 22.0 150.5
Morishima and associatesl described the numerous problems involved in establishing a primate preparation such as ours. The operations and anesthetic techniques needed are detrimental to the fetus. It is often difficult to return to baseline conditions. Therefore, data are gathered from a preparation undergoing progressive de-
Also, although the mild degree of fetal bradycardia consequent upon the spinal block was corrected by ephedrine, the fall in fetal blood pressure was unaffected. I would be interested to know how, on the
295
296
Correspondence
terioration. 2 These changes are reflected in the steady decrease in base excess and fetal blood pressure. If, on this sloping base line, one observes improvement, i.e., an increase in fetal Po 2 and a decrease in fetal Pco 2 as observed in Fetuses c and d, or deviation from expected deterioration, as suggested in Fetuses a and b, then we can conclude that the ephedrine was beneficial to the fetus. Marlene Eng, M.D. Department of Anesthesiology llniversity of ~ashington School of Medicine Seattle, ~ashington 98195 REFERENCES
1. Morishima, H. 0., Hyman, A. 1., Adamsons,
K., and Janus, L. S.: AM. J. 0BSTET. GYNECOL. 110: 926, 1972. 2. Behrman, R. E., Parer, J. T., and Novy, M. J.: Pediatr. Res. 1: 354, 1967.
Group B beta hemolytic streptococcus infections in newborn infants To the Editors: A report appeared in the May 1, 1973, issue of the AMERICAN JOURNAL OF OBSTETRICS AND GYNECOLOGY, on page 43, by Hey and associates documenting problems with infections caused by the group B beta hemolytic streptococcus in newborn infants. Seven of the 8 infants had sudden onset of symptoms and a rapidly fatal course because of infection with this organism. The article logically points out the concerns in the detection and prevention of this infection and suggests that further study needs to be done to see whether there is a way to prevent or reduce the incidence of such occurrences. Recently, in the April, 1973, issue of the Journal of Pediatrics, a number of articles were devoted to this problem with an accompanying editorial comment that established a pattern of practice that is of concern to me. The editors suggested that all women should be screened for the presence of the group B beta hemolytic streptococcus late in the third trimester and that those women with positive cultures, as well as their husbands, should be treated with penicillin. I have enclosed a letter that a number of concerned pediatricians have written to the editor of the Journal of Pediatrics with the hope that this letter could be reproduced and made available to practicing obstetricians. I have been impressed in conversations with a number of obstetric chiefs from across the country that
Am.
J.
January 15, 1974 Ob,tec Gynecol.
this pattern of practice with the widespread usage of penicillin has already been established in many medical centers. I believe it is important for obstetricians to know that studies establishing the benefits of this therapeutic plan have not been performed as yet. William f. Ledger, M.D. ~omen's Hospital 1240 N. Mission Rd. Los Angeles, California 9()()33
To the Editors: The recent report by Franciosi and associates1 and the accompanying editorial by McCracken,2 concerning the importance of group B beta hemolytic streptococci as a cause of neonatal sepsis, make recommendations for prophylactic chemotherapy during pregnancy which we feel are not justified on the basis of the available data. These communications recommend that all pregnant women have vaginal cultures late in pregnancy, and those found to be carrying group B beta hemolytic streptococci should be treated with benzathine penicillin in order to eradicate the organism and to reduce or eliminate the risk of a highly lethal episode of group B streptococcal sepsis in the neonate. Several assumptions on which these recommendations are based seem to us to be very much in question. First, there is no documentation in the literature that such management of pregnant women will reduce the incidence of group B streptococcal sepsis. We agree that in virtually all studies in which sufficient data have been presented the mother-to-infant route of transmission emerges as the critical one. That this route of transmission can be successfully interrupted by this type of penicillin therapy is not established. Second, little is known of the dynamics of vaginal carriage of group B streptococci. A vaginal carriage rate of 5 to 8 per cent among pregnant women appears to be confirmed.1 • 3 • ' Baker and Barrett,5 using selective media, were able to identify group B streptococci in 24.4 per cent of 205 maternal vaginal cultures. The rate of appearance or disappearance of these organisms, as well as the duration of carriage, however, are unknown. Basic epidemiologic principles demand the inclusion of a control group before any valid conclusions can be derived concerning the efficiency of penicillin therapy in eradicating vaginal carriage of group B streptococci.
basis of these data, the authors concluded that ephedrine administered in the given circumstance was in any way beneficial to the fetus. J. Selwyn Crawford Consultant Anaesthetist
To the Editors: Although reluctant to raise controversy in the JouRNAL, I must protest that several of the conclusions reached by Dr. Eng and colleagues ( 115: 1095, 1973) are by no means supported by the evidence presented. It is claimed that following the administration of ephedrine to the mother who had received a spinal block the fetal arterial Po 2 and Pco 2 returned to the prespinal levels (in the Abstract this is amended to the suggestion that ephedrine prevents further deterioration of the fetus). We are not provided with the absolute figures, but my reading of the diagrams contained in the article (and I hope that the authors will correct me if I am wrong) is as follows:
Fetal Po,
Fetal Pco,
a b c d a b c
d
17
:25 38 21 25 33 45 48 40
28 10 10 37 48 54 61
The Birmingham Maternity Hospital Queen Elizabeth Medical Centre Edgbaston, Birmingham, Bl5 2TG, England
Reply to Dr. Crawford To the Editors: We want to thank Mr. Crawford for calling our attention to an error which escaped correc· tion. The sentence from our article on page 1099 should read, "As a result, uterine blood flow increased and fetal Po2 and Pco 2 returned toward prespinal levels." The absolute values upon which Figs. 1 and 2 are based are as follows:
I
20 29 12 20 38 48 49 50
Case
a A b
B c
c
These can hardly be characterized as portraying a "return to prespinal levels." Furthermore, the authors fail, in their discussion, to draw attention to the fact that, according to the mean values obtained from the 4 fetuses, the metabolic acidosis associated with the spinal block, far from being reversed by ephedrine, was actually worsened following administration of the vasopressor:
d D
pH Base excess
7.34 -2.6
Spinal
Ephedrine
7.22
7.21 -9.8
-6.3
F M
F M F M F M
I
33.8 30.2 45.2 37.2 47.5 35.8 40.0 35.5
I
37.4 25.2 49.0 32.5 55.4 30.8 61.8 32.6
38.8 22.3 49.4 30.8 49.5 33.3 49.9 34.2
Arterial Po, a
A b
B c
c
d Control
Arterial Pco, Fetal or maternal Control Spinal Ephedrine
D
F M F M F M F M
25.0 52.5 36.5 114.5 22.0 134.0 ~5.0
137.0
14.0 63.5 26.8 116.5 11.0 144.0 10.0 156.5
20.5 97.5 28.5 124.0 14.0 143.0 22.0 150.5
Morishima and associatesl described the numerous problems involved in establishing a primate preparation such as ours. The operations and anesthetic techniques needed are detrimental to the fetus. It is often difficult to return to baseline conditions. Therefore, data are gathered from a preparation undergoing progressive de-
Also, although the mild degree of fetal bradycardia consequent upon the spinal block was corrected by ephedrine, the fall in fetal blood pressure was unaffected. I would be interested to know how, on the
295
296
Correspondence
terioration. 2 These changes are reflected in the steady decrease in base excess and fetal blood pressure. If, on this sloping base line, one observes improvement, i.e., an increase in fetal Po 2 and a decrease in fetal Pco 2 as observed in Fetuses c and d, or deviation from expected deterioration, as suggested in Fetuses a and b, then we can conclude that the ephedrine was beneficial to the fetus. Marlene Eng, M.D. Department of Anesthesiology llniversity of ~ashington School of Medicine Seattle, ~ashington 98195 REFERENCES
1. Morishima, H. 0., Hyman, A. 1., Adamsons,
K., and Janus, L. S.: AM. J. 0BSTET. GYNECOL. 110: 926, 1972. 2. Behrman, R. E., Parer, J. T., and Novy, M. J.: Pediatr. Res. 1: 354, 1967.
Group B beta hemolytic streptococcus infections in newborn infants To the Editors: A report appeared in the May 1, 1973, issue of the AMERICAN JOURNAL OF OBSTETRICS AND GYNECOLOGY, on page 43, by Hey and associates documenting problems with infections caused by the group B beta hemolytic streptococcus in newborn infants. Seven of the 8 infants had sudden onset of symptoms and a rapidly fatal course because of infection with this organism. The article logically points out the concerns in the detection and prevention of this infection and suggests that further study needs to be done to see whether there is a way to prevent or reduce the incidence of such occurrences. Recently, in the April, 1973, issue of the Journal of Pediatrics, a number of articles were devoted to this problem with an accompanying editorial comment that established a pattern of practice that is of concern to me. The editors suggested that all women should be screened for the presence of the group B beta hemolytic streptococcus late in the third trimester and that those women with positive cultures, as well as their husbands, should be treated with penicillin. I have enclosed a letter that a number of concerned pediatricians have written to the editor of the Journal of Pediatrics with the hope that this letter could be reproduced and made available to practicing obstetricians. I have been impressed in conversations with a number of obstetric chiefs from across the country that
Am.
J.
January 15, 1974 Ob,tec Gynecol.
this pattern of practice with the widespread usage of penicillin has already been established in many medical centers. I believe it is important for obstetricians to know that studies establishing the benefits of this therapeutic plan have not been performed as yet. William f. Ledger, M.D. ~omen's Hospital 1240 N. Mission Rd. Los Angeles, California 9()()33
To the Editors: The recent report by Franciosi and associates1 and the accompanying editorial by McCracken,2 concerning the importance of group B beta hemolytic streptococci as a cause of neonatal sepsis, make recommendations for prophylactic chemotherapy during pregnancy which we feel are not justified on the basis of the available data. These communications recommend that all pregnant women have vaginal cultures late in pregnancy, and those found to be carrying group B beta hemolytic streptococci should be treated with benzathine penicillin in order to eradicate the organism and to reduce or eliminate the risk of a highly lethal episode of group B streptococcal sepsis in the neonate. Several assumptions on which these recommendations are based seem to us to be very much in question. First, there is no documentation in the literature that such management of pregnant women will reduce the incidence of group B streptococcal sepsis. We agree that in virtually all studies in which sufficient data have been presented the mother-to-infant route of transmission emerges as the critical one. That this route of transmission can be successfully interrupted by this type of penicillin therapy is not established. Second, little is known of the dynamics of vaginal carriage of group B streptococci. A vaginal carriage rate of 5 to 8 per cent among pregnant women appears to be confirmed.1 • 3 • ' Baker and Barrett,5 using selective media, were able to identify group B streptococci in 24.4 per cent of 205 maternal vaginal cultures. The rate of appearance or disappearance of these organisms, as well as the duration of carriage, however, are unknown. Basic epidemiologic principles demand the inclusion of a control group before any valid conclusions can be derived concerning the efficiency of penicillin therapy in eradicating vaginal carriage of group B streptococci.