- Email: [email protected]
Estimation of blood volume in pregnant patients
CORRESPONDENCE
intra-amniotic Intualon of antImlc~ drUp To the Editors:
I was intrigued by the letter, "Intra-amniotic antibiotic infusion" (AM. J. OBSTET. GYNECOL. 139:975, 1981), by Dr. Robert C. Goodlin. It would seem rather easy to comprehend how, in the face of intact amniotic membranes, one could deliver therapeutic levels of antimicrobial drug(s) by means of infusion at the time of transabdominal amniocentesis. However, I am confused, as I would think other readers might be, how transcervical delivery of antimicrobials via the catheter supplied for intrapartum fetal monitoring will allow achievement of therapeutic levels of any drug. It has been my personal experience that just the relatively small volume of fluid used from time to time to flush and clear the catheter runs right out after infused. I and, I would imagine, others would be interested to learn of Dr. Goodlin's data and studies with respect to this matter, including measurement of antimicrobial levels in the fluid, fetus, amniotic membranes, and uterus after utilization of his technique of transcervical antimicrobial administration. I would hope his study would include a control group infused with sterile normal saline in a 500 ml volume, without any antimicrobial drug, over a I-hour time period, in order to exclude the possibility that the beneficial effect of his proposed management is not due merely to the salutary effects of irrigation alone, a technique used quite effectively for decontamination of other contaminated anatomic sites from a host of different etiologies. This would prove that the benefits of Dr. Goodlin's technique are truly derived from this clever on-site and direct delivery of the antimicrobial drug(s) used. Sylvain Fribourg, M.D., F.A .C.O.G. Southern California Permanente Medical Group Obstetrics and Gynecology Department 13652 Cantara Street Panorama City, California 91402
ter is just barely inserted, often mOSt of the infused fluid will run backthrough the vagina. However, in my experience the fetal presenting partin thf;!Se caSes is usually not applied tightly to the cervix: If, however, fluid begins to leak out of the cerviX, the catheter is simply "manipulated" and the cervical loss usually ceases. As with many procedures, those with less enthusiasm have the higher failure rate. In two cases we infused radiopaque solutions through the transcervical catheter and an x-Tay film was obtained 90 minutes later. In one case the contrast medium was distributed evenly throughout the amniotic cavity but in the second case only "pooling" of the contrast medium could be seen in the lower uterine segment. In both cases, the mother had absorbed enough contrast medium so that a faint pylogram was apparent. Carey* reported that significant levels of penicillin appeared in both maternal and fetal 5(!rum after amniotic infusions. We have simultaneously used antibiotics intravenously while · giving the intra-am.niotic infusions, invalidating any studies of serum levels. . Over the intervening years, we have set up controlled series. However, for various reasons, we have never been able to collect sufficient cases for the "control" group as proposed by Dr. Fribourg. I have feared that saline lavage alone in an infected amniotic cavity may aggravate or lead to maternal septicemia. Robert C. Goodlin, M.D. Department of Obstetrics and Glnecology University of Nebraska Medical Center 42nd and Dewey Avenue Omaha, Nebraska 68105 *Carey, W. H.: Postgraduate obstetrics and gynecology course, Minneapolis, Minnesota, October 15, 1957, Uriiversity of Minnesota.
eelillllllonofblOodYOlt-.InI'olI •• _
_ ..,.. .. .
To the Editors: Reply to Dr. Fribourg
In the December 15, 1980, edition of the AM,EIUCAN OF OBSTETIUCS AND GYNECOLOGY, I proposed a formula for estimating blood volume in preg~nt patients. The formula, blood volume (mllkg) = 24 -0-.-8-6-x-h-=e:..:m:....a-t-oc-ri-t'"-- x 100, contains the number
To the Editors:
JOURNAL
Dr. Fribourg has expressed concerns about the concepts of transcervical antibiotic infusions which have been expressed by others over the 25 years that I have suggested the technique. If the fetal presenting part is closely applied to the cervix and the transcervical cathe-
24, which is the mean red blood cell volume reported
592
Volume 141 Number 5
-
•
0)
26
.s
25
E (5
23 22
()
21
a:
20
.x:
Q)
~
> al
Correspondence 593
24
REFERENCE y,:30.73-0.095x r= 0.824
•
•
1. Gahres, E. E., Albert, S. N., and Dodek, S. M.: Normal
antepartum red cell volume measured wi~h crt-tagged erythrocytes, AM. J. OBSTET. GYNECOL. 84:770, 1962 .
Tnt tubebabie8: Fact or flctton? To the Editors: 50
60
70
90
80
100
Body Weight (kg) Fi,. 1. Relationship between body weight and red blood cell volume (milliliters per kilogram) in pregnant women.
Table I. Relationship between body weight and red blood' cell volume in pregnant women Body weight (kg) 45-55 56-65 66-75 76-85 86-95 96-105
Red blood cell volume (mllkg) 26
25
24 23 22
21
by Gahres and associates. I I Slate that this figure of 24 is reasonably consistent throughQut a range of patient weights from 50 to 100 kg. While this is true, the use of the number 24 for all patients does underestimate the blood volume of small patients and overestimate the blood volume of large patients. For those obstetricians who would like to be more accurate in their estimation, I would like to propose a modification in the original formula. A graph of the dala of Gahres and associates in which red blood cell volume in milliliters per kilogram is plotted against body weight in kilograms is illustrated in Fig. 1. The line drawn in the graph connects the points of red blood cell volume, 26, and body weight, 50, with red blood cell volume, 21, and body weight, 100. This line is extremely close to that yielded by the formula shown in the figure. Therefore, my proposed modification would be not to use the number 24 for all patients but rather to use a number which would be determined by the patient's body weight. The proposed numbers between a range of body weights from 45 to 105 kg are listed in Table 1. While it is fully realized that this formula gives only an estimation of blood volume, I firmly believe that consideration of blood loss at delivery as a percentage of the patient's blood volume can only result in better postpartum care. George H. Nelson, Ph.D., M.D . Department rif Obstetrics and Gynecology Medical College of Georgia Augusta, Georgia 30912
There is an urgent need to review briefly and update the widely publicized "test tube" baby procedure (in vitro fertilization and embryo transfer) as itrelates to helping sterile women become pregnant.. To put this topic into proper perspective, it is meaningful to cite the position of The American College of Obstetricians and Gynecologists in this matter (ACOG Newsletter, November, 1978). Its position on this topic is as follows: The American College of Obstetricians and Gynecologists is aware of the fact that many of its Fellows are being approached by patients whose hopes have been raised by recent events in England. leading to the birth of a baby following in vitro fertilization and embryo transfer. Without at this time making any judgments about the many technical and ethical issues still to be resolved in this subject, the College feels a responsibility to comment now on one aspect of the events in England. Given the many complexities of the subject. the College strongly urges couples not to expect that this method of procreation will afford relief of infertility problems to many in the foreseeable future . The College therefore urges couples with infertility problems to pursue the currently available options of parenthood and not to base any decisions on the likelihood of having these new techniques avail
Observations about the successful use of in vitro fertilization and embryo transfer in sterility, which is commonly known as the "test-tube" baby procedure, by Biggers, in The New England Journal of Medicine (304: 336, 1981), merit an opposing viewpoint. Biggers implies, in so many words, that other than in vitro fertilization and embryo transfer, there is no hope for the countless thousands of women troubled by sterility which is due to hopelessly diseased or surgically excised fallopian tubes. Clinical experience with the fertilityenhancing Estes!' 2 operation, as far back as 1909, disputes this observation by Biggers. The once-historic Estes operation, in which the ovum-bearing ovary is sutured to the site where the previously excised fallopian tube entered into the uterine cavity, near the cornu, appears to provide a considerably greater chance for a future pregnancy than the estimated less than 1% predicted for "test-tube" babies conceived in a laboratory. Letters to the Editor 3• 4 ofFertiliJy and Sterility by infertility specialists support my favorable experiences with the Estes operation in the Orient during the immediate years before World War II, which were discussed in an earlier issue of that particular journaP ]\:0 one can quarrel with the statement that recanalization of fallopian tubes resulting in pregnancy does
intra-amniotic Intualon of antImlc~ drUp To the Editors:
I was intrigued by the letter, "Intra-amniotic antibiotic infusion" (AM. J. OBSTET. GYNECOL. 139:975, 1981), by Dr. Robert C. Goodlin. It would seem rather easy to comprehend how, in the face of intact amniotic membranes, one could deliver therapeutic levels of antimicrobial drug(s) by means of infusion at the time of transabdominal amniocentesis. However, I am confused, as I would think other readers might be, how transcervical delivery of antimicrobials via the catheter supplied for intrapartum fetal monitoring will allow achievement of therapeutic levels of any drug. It has been my personal experience that just the relatively small volume of fluid used from time to time to flush and clear the catheter runs right out after infused. I and, I would imagine, others would be interested to learn of Dr. Goodlin's data and studies with respect to this matter, including measurement of antimicrobial levels in the fluid, fetus, amniotic membranes, and uterus after utilization of his technique of transcervical antimicrobial administration. I would hope his study would include a control group infused with sterile normal saline in a 500 ml volume, without any antimicrobial drug, over a I-hour time period, in order to exclude the possibility that the beneficial effect of his proposed management is not due merely to the salutary effects of irrigation alone, a technique used quite effectively for decontamination of other contaminated anatomic sites from a host of different etiologies. This would prove that the benefits of Dr. Goodlin's technique are truly derived from this clever on-site and direct delivery of the antimicrobial drug(s) used. Sylvain Fribourg, M.D., F.A .C.O.G. Southern California Permanente Medical Group Obstetrics and Gynecology Department 13652 Cantara Street Panorama City, California 91402
ter is just barely inserted, often mOSt of the infused fluid will run backthrough the vagina. However, in my experience the fetal presenting partin thf;!Se caSes is usually not applied tightly to the cervix: If, however, fluid begins to leak out of the cerviX, the catheter is simply "manipulated" and the cervical loss usually ceases. As with many procedures, those with less enthusiasm have the higher failure rate. In two cases we infused radiopaque solutions through the transcervical catheter and an x-Tay film was obtained 90 minutes later. In one case the contrast medium was distributed evenly throughout the amniotic cavity but in the second case only "pooling" of the contrast medium could be seen in the lower uterine segment. In both cases, the mother had absorbed enough contrast medium so that a faint pylogram was apparent. Carey* reported that significant levels of penicillin appeared in both maternal and fetal 5(!rum after amniotic infusions. We have simultaneously used antibiotics intravenously while · giving the intra-am.niotic infusions, invalidating any studies of serum levels. . Over the intervening years, we have set up controlled series. However, for various reasons, we have never been able to collect sufficient cases for the "control" group as proposed by Dr. Fribourg. I have feared that saline lavage alone in an infected amniotic cavity may aggravate or lead to maternal septicemia. Robert C. Goodlin, M.D. Department of Obstetrics and Glnecology University of Nebraska Medical Center 42nd and Dewey Avenue Omaha, Nebraska 68105 *Carey, W. H.: Postgraduate obstetrics and gynecology course, Minneapolis, Minnesota, October 15, 1957, Uriiversity of Minnesota.
eelillllllonofblOodYOlt-.InI'olI •• _
_ ..,.. .. .
To the Editors: Reply to Dr. Fribourg
In the December 15, 1980, edition of the AM,EIUCAN OF OBSTETIUCS AND GYNECOLOGY, I proposed a formula for estimating blood volume in preg~nt patients. The formula, blood volume (mllkg) = 24 -0-.-8-6-x-h-=e:..:m:....a-t-oc-ri-t'"-- x 100, contains the number
To the Editors:
JOURNAL
Dr. Fribourg has expressed concerns about the concepts of transcervical antibiotic infusions which have been expressed by others over the 25 years that I have suggested the technique. If the fetal presenting part is closely applied to the cervix and the transcervical cathe-
24, which is the mean red blood cell volume reported
592
Volume 141 Number 5
-
•
0)
26
.s
25
E (5
23 22
()
21
a:
20
.x:
Q)
~
> al
Correspondence 593
24
REFERENCE y,:30.73-0.095x r= 0.824
•
•
1. Gahres, E. E., Albert, S. N., and Dodek, S. M.: Normal
antepartum red cell volume measured wi~h crt-tagged erythrocytes, AM. J. OBSTET. GYNECOL. 84:770, 1962 .
Tnt tubebabie8: Fact or flctton? To the Editors: 50
60
70
90
80
100
Body Weight (kg) Fi,. 1. Relationship between body weight and red blood cell volume (milliliters per kilogram) in pregnant women.
Table I. Relationship between body weight and red blood' cell volume in pregnant women Body weight (kg) 45-55 56-65 66-75 76-85 86-95 96-105
Red blood cell volume (mllkg) 26
25
24 23 22
21
by Gahres and associates. I I Slate that this figure of 24 is reasonably consistent throughQut a range of patient weights from 50 to 100 kg. While this is true, the use of the number 24 for all patients does underestimate the blood volume of small patients and overestimate the blood volume of large patients. For those obstetricians who would like to be more accurate in their estimation, I would like to propose a modification in the original formula. A graph of the dala of Gahres and associates in which red blood cell volume in milliliters per kilogram is plotted against body weight in kilograms is illustrated in Fig. 1. The line drawn in the graph connects the points of red blood cell volume, 26, and body weight, 50, with red blood cell volume, 21, and body weight, 100. This line is extremely close to that yielded by the formula shown in the figure. Therefore, my proposed modification would be not to use the number 24 for all patients but rather to use a number which would be determined by the patient's body weight. The proposed numbers between a range of body weights from 45 to 105 kg are listed in Table 1. While it is fully realized that this formula gives only an estimation of blood volume, I firmly believe that consideration of blood loss at delivery as a percentage of the patient's blood volume can only result in better postpartum care. George H. Nelson, Ph.D., M.D . Department rif Obstetrics and Gynecology Medical College of Georgia Augusta, Georgia 30912
There is an urgent need to review briefly and update the widely publicized "test tube" baby procedure (in vitro fertilization and embryo transfer) as itrelates to helping sterile women become pregnant.. To put this topic into proper perspective, it is meaningful to cite the position of The American College of Obstetricians and Gynecologists in this matter (ACOG Newsletter, November, 1978). Its position on this topic is as follows: The American College of Obstetricians and Gynecologists is aware of the fact that many of its Fellows are being approached by patients whose hopes have been raised by recent events in England. leading to the birth of a baby following in vitro fertilization and embryo transfer. Without at this time making any judgments about the many technical and ethical issues still to be resolved in this subject, the College feels a responsibility to comment now on one aspect of the events in England. Given the many complexities of the subject. the College strongly urges couples not to expect that this method of procreation will afford relief of infertility problems to many in the foreseeable future . The College therefore urges couples with infertility problems to pursue the currently available options of parenthood and not to base any decisions on the likelihood of having these new techniques avail
Observations about the successful use of in vitro fertilization and embryo transfer in sterility, which is commonly known as the "test-tube" baby procedure, by Biggers, in The New England Journal of Medicine (304: 336, 1981), merit an opposing viewpoint. Biggers implies, in so many words, that other than in vitro fertilization and embryo transfer, there is no hope for the countless thousands of women troubled by sterility which is due to hopelessly diseased or surgically excised fallopian tubes. Clinical experience with the fertilityenhancing Estes!' 2 operation, as far back as 1909, disputes this observation by Biggers. The once-historic Estes operation, in which the ovum-bearing ovary is sutured to the site where the previously excised fallopian tube entered into the uterine cavity, near the cornu, appears to provide a considerably greater chance for a future pregnancy than the estimated less than 1% predicted for "test-tube" babies conceived in a laboratory. Letters to the Editor 3• 4 ofFertiliJy and Sterility by infertility specialists support my favorable experiences with the Estes operation in the Orient during the immediate years before World War II, which were discussed in an earlier issue of that particular journaP ]\:0 one can quarrel with the statement that recanalization of fallopian tubes resulting in pregnancy does