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Auscultation of the fetal heart: How to do it
1078
Letters
October 1993 Am J Obstet Gynecol
Fig. 1. Sono gram of 8-week gestation. Intervillous space (arrow) and blood flow within spiral arteries (arrowhead) are clearly identified.
iologic characteristics of the early uteroplacental circulation. Richard Jaffe, MD Division of Maternal-Fetal Medicine, University of Rochester School of Medicine and Dentistry, 601 Elmwood Ave., Rochester, NY 14642-8668
Olga Genbacev, PhD
Environmental Health Science Center, University of Rochester School of Medicine and Dentistry, 601 Elmwood Ave., Rochester, NY 14642-8668
REFERENCES 1. Hustin J, Schaaps JP. Echocardiographic and anatomic studies of the maternotrophoblastic border during the first trimester of pregnancy. AM J OSSTET GYNECOL 1987;157: 162-8. 2. Jaumaux E,Jurkovic D, CampbeII S. In-vivo investigation of the anatomy and the physiology of early human placental circulation. J Ultrasound Obstet Gynecol 1991; 1:435-45. 3. Tal J, Kaplan M, Sharf M, Barnea ER. Stress-related hormones affect human chorionic gonadotropin secretions from early human placenta in-vitro. Hum Reprod 1991;6: 766-9. 4. Licht P, Harbarth P, Merz WE. Evidence for a modulation of human chorionic gonadotropin (HCGl subunit messenger ribonucleic acid levels and HCG secretions by -y-aminobutyric acid in human first trimester placenta in-vitro. Endocrinology 1992; 130:490-6.
Auscultation of the fetal heart: How to do it To the Editors: Morrison et al. report their experience with intrapartum fetal heart rate assessment (Morrison lC, Chez BF, Davis ID, et al. Intrapartum fetal heart rate assessment: Monitoring by auscultation or electronic means. AM 1 OBSTET GYNECOL 1993;168:63-6). Their conclusion that "it is not possible to use auscultation as a primary means of fetal surveillance during labor in the majority of parturients" is strikingly different than ours. 1 Their misinterpretation of the published
literature has made their auscultation and recording requirements unnecessarily cumbersome. The authors' auscultation protocol differs from the recommendations of The American College of Obstetricians and Gynecologists 2 and the studies from which it was derived in the following significant ways: (l) the requirements of auscultation every 15 to 30 minutes for latent labor,3 (2) requiring second-stage auscultation every 5 minutes in patients without risk factors instead of the published criteria of 15 minutes,"-4 (3) requiring auscultation during a contraction,"· 4 (4) requiring the auscultation and recording for 1 full minute instead of for 30 seconds immediately after a contraction,2. 4 and (5) requiring a 1 : 1 nurse/patient ratio for parturients without risk factors." Could the authors have initiated auscultation in more parturients by following the simple protocol guidelines of The American College of Obstetricians and Gynecologists and other published studies? The more unusual reason for the nurses' inability to continue auscultation was their inability to meet recording requirements-163 of the 423 auscultated parturients. The exclusion of nonreassuring fetal heart rates (FHRs) can be accomplished by finding a normal rate during the first 30 seconds after a contraction. If the total number of beats during that 30 seconds is normal (60 to 80), nonreassuring FHRs are not present and auscultation for a longer time period is not necessary. With a simplified flow sheet, the FHR can be recorded in < 5 seconds. Why did simple recording requirements preclude continuation of auscultation for 163 of the authors' 423 auscultated parturients? During the 3-month study period 20 nurses auscultated only a total of 31 patients throughout labor. Were the authors and their nurses still on the learning curve at the time of abandoning their auscultation protocol? The authors have misinterpreted our frequencY of
Volume 169, Number 4 Am J Obstet Gynecol
Letters
late assessments of less than once per five patients auscultated in each of the first and second stages of labor as > 20%. Actually, with a mean of approximately 20 auscultations per labor patient, this represents only 2% of all assessments.! The authors value electronic FHR monitoring as being helpful for decreasing liability risks when the strip is normal. I agree for the 9% of strips that are normal; however, the other 91 % with one or more abnormalities 5 are not uniformly interpreted by different obstetricians and certainly not by opposing expert witnesses. In contrast, the auscultation protocol results in obstetric interventions that are based on objective observations. The authors should be encouraged to resume their study but with an appropriate auscultation protocol and by comparing nursing staff time requirements with those associated with the more time consuming evaluation and recording of electronic FHRs.
Herbert Sandmire, MD 704 S. Webster Ave., Green Bay, WI54301
1.
2.
3.
4.
5.
REFERENCES Sandmire HF. Whither electronic fetal monitoring? Ob stet Gynecol 1990;76:1130-4. American College of Obstetricians and Gynecologists. Intrapartum fetal heart rate monitoring. Washington: American College of Obstetricians and Gynecologists, 1989 Sept; Technical bulletin no 132. Organization for Obstetric, Gynecologic, and Neonatal Nurses. Fetal heart rate auscultation. Washington: Organization for Obstetric, Gynecologic, and Neonatal Nurses, 1990 March. American Academy of Pediatrics and American College of Obstetricians and Gynecologists. Guidelines for perinatal care. 2nd ed. Washington: American Academy of Pediatrics and American College of Obstetricians and Gynecologists, 1988:67. Krebs HB, Petres RE, Dunn LJ. Intrapartum fetal heart rate monitoring. V. Fetal heart rate patterns in the second stage of labor. AM J OBSTET GYNECOL 1981;140:435-9. Reply
To the Editors: We appreciate the comments of Sand mire regarding our article about intrapartum monitoring with auscultation. Apparently, from their questions, they have misinterpreted our comments. Although the limits of my reply will not allow a line-by-line comparison of the Material and methods portion of our article with Sandmire's comments, I would say in general that we indeed followed the recommendations of The American College of Obstetricians and Gynecologists. An example is Dr. Sandmire's misunderstanding that a 1: 1 nurse/patient ratio is not necessary unless risk factors are present. The American College of Obstetricians and Gynecologists Technical Bulletin states quite clearly that "Such auscultation is usually performed during a contraction and for thirty seconds thereafter. AI: 1 nurse-patient ratio is required if auscultation is used as the primary technique of fetal heart rate surveillance" (emphasis added). We also believe that nursing experience was not a factor as the protocol section of our report clearly demonstrates. The gist of our argument is that if auscultation is used according to the strict guidelines noted in the Technical Bulletin, it is not often possible to use this technique as the primary
1079
means of surveillance unless the guidelines are violated. The authors also state that we misinterpreted their frequency of "late assessments" as 20% when it was actually only 2% of all assessments. The exact wording of Sand mire's statement is as follows: "Late auscultation occurred less than once per five patients auscultated in each of the first and second stages of labor." If all the patients received auscultation as their primary means of surveillance during both stages of labor and one of five of those patients had one or more "late auscultations," that appears to be nearer to 20% than to 2%. It doesn't make any difference whether the mean number of auscultations was 20 or 200; if you miss one, you simply miss it. As we all know, most plaintiffs' attorneys can definitely tell you when fetal damage occurred - it was when the nurse-physician was not auscultating and this violates the protocol in their labor and delivery suite. The authors question the inability to continue auscultation on the basis of recording requirements. Although Sandmire is correct that it may take < 5 seconds to record the fetal heart rate, there are other nursing duties that are necessary. One may need to rotate the patient back to her side, rearrange her coverings, answer questions that the patient and family have, respond to analgesic needs, ete. I don't know about the readers but our nursing personnel frequently address these issues, and sometimes this makes them late in recording data at specific time intervals; perhaps this is only a problem in Mississippi, but I don't think so. Sandmire does agree that electronic FHR monitoring is helpful in decreasing the liability risk when the strip is normal, but he says that a normal strip only occurs 9% of the time. It's odd that he uses a 1981 reference, which only has to do with the second stage of labor, to validate his point. In contrast, I think clinicians are very much aware that what we are really looking for by using electronic FHR monitoring are nonreassuring or worrisome signs that would make one consider ancillary diagnostic procedures or delivery. Although many strips have occasional decelerations or periods of less than average short-term variability, probably not more than 10% to 20% of assessments would qualify for these further considerations. In those electronic FHR monitoring strips (dependent on the response to maternal and in utero fetal resuscitation and other clinical factors) most obstetricians can use these data to document that fetal compromise is not occurring. Under current guidelines either auscultation or electronic fetal monitoring is appropriate for intrapartum FHR surveillance. Nevertheless, after some 20 years of experience with both types of assessment I remain unconvinced that auscultation offers the best method of assessing fetal health in utero. I believe auscultation is not as objective as FHR monitoring in assuring fetal health nor is it as helpful to the obstetrician in ruling out intrapartum asphyxia. Finally, given a permanent record generated by FHR monitoring, I believe provider liability is reduced when compared with auscultation. John C. Morrison, MD Department of Obstetrics and Gynecology, University. of MississiPPi Medical Center, 2500 N. State St., Jackson, MI 39216-4505
Letters
October 1993 Am J Obstet Gynecol
Fig. 1. Sono gram of 8-week gestation. Intervillous space (arrow) and blood flow within spiral arteries (arrowhead) are clearly identified.
iologic characteristics of the early uteroplacental circulation. Richard Jaffe, MD Division of Maternal-Fetal Medicine, University of Rochester School of Medicine and Dentistry, 601 Elmwood Ave., Rochester, NY 14642-8668
Olga Genbacev, PhD
Environmental Health Science Center, University of Rochester School of Medicine and Dentistry, 601 Elmwood Ave., Rochester, NY 14642-8668
REFERENCES 1. Hustin J, Schaaps JP. Echocardiographic and anatomic studies of the maternotrophoblastic border during the first trimester of pregnancy. AM J OSSTET GYNECOL 1987;157: 162-8. 2. Jaumaux E,Jurkovic D, CampbeII S. In-vivo investigation of the anatomy and the physiology of early human placental circulation. J Ultrasound Obstet Gynecol 1991; 1:435-45. 3. Tal J, Kaplan M, Sharf M, Barnea ER. Stress-related hormones affect human chorionic gonadotropin secretions from early human placenta in-vitro. Hum Reprod 1991;6: 766-9. 4. Licht P, Harbarth P, Merz WE. Evidence for a modulation of human chorionic gonadotropin (HCGl subunit messenger ribonucleic acid levels and HCG secretions by -y-aminobutyric acid in human first trimester placenta in-vitro. Endocrinology 1992; 130:490-6.
Auscultation of the fetal heart: How to do it To the Editors: Morrison et al. report their experience with intrapartum fetal heart rate assessment (Morrison lC, Chez BF, Davis ID, et al. Intrapartum fetal heart rate assessment: Monitoring by auscultation or electronic means. AM 1 OBSTET GYNECOL 1993;168:63-6). Their conclusion that "it is not possible to use auscultation as a primary means of fetal surveillance during labor in the majority of parturients" is strikingly different than ours. 1 Their misinterpretation of the published
literature has made their auscultation and recording requirements unnecessarily cumbersome. The authors' auscultation protocol differs from the recommendations of The American College of Obstetricians and Gynecologists 2 and the studies from which it was derived in the following significant ways: (l) the requirements of auscultation every 15 to 30 minutes for latent labor,3 (2) requiring second-stage auscultation every 5 minutes in patients without risk factors instead of the published criteria of 15 minutes,"-4 (3) requiring auscultation during a contraction,"· 4 (4) requiring the auscultation and recording for 1 full minute instead of for 30 seconds immediately after a contraction,2. 4 and (5) requiring a 1 : 1 nurse/patient ratio for parturients without risk factors." Could the authors have initiated auscultation in more parturients by following the simple protocol guidelines of The American College of Obstetricians and Gynecologists and other published studies? The more unusual reason for the nurses' inability to continue auscultation was their inability to meet recording requirements-163 of the 423 auscultated parturients. The exclusion of nonreassuring fetal heart rates (FHRs) can be accomplished by finding a normal rate during the first 30 seconds after a contraction. If the total number of beats during that 30 seconds is normal (60 to 80), nonreassuring FHRs are not present and auscultation for a longer time period is not necessary. With a simplified flow sheet, the FHR can be recorded in < 5 seconds. Why did simple recording requirements preclude continuation of auscultation for 163 of the authors' 423 auscultated parturients? During the 3-month study period 20 nurses auscultated only a total of 31 patients throughout labor. Were the authors and their nurses still on the learning curve at the time of abandoning their auscultation protocol? The authors have misinterpreted our frequencY of
Volume 169, Number 4 Am J Obstet Gynecol
Letters
late assessments of less than once per five patients auscultated in each of the first and second stages of labor as > 20%. Actually, with a mean of approximately 20 auscultations per labor patient, this represents only 2% of all assessments.! The authors value electronic FHR monitoring as being helpful for decreasing liability risks when the strip is normal. I agree for the 9% of strips that are normal; however, the other 91 % with one or more abnormalities 5 are not uniformly interpreted by different obstetricians and certainly not by opposing expert witnesses. In contrast, the auscultation protocol results in obstetric interventions that are based on objective observations. The authors should be encouraged to resume their study but with an appropriate auscultation protocol and by comparing nursing staff time requirements with those associated with the more time consuming evaluation and recording of electronic FHRs.
Herbert Sandmire, MD 704 S. Webster Ave., Green Bay, WI54301
1.
2.
3.
4.
5.
REFERENCES Sandmire HF. Whither electronic fetal monitoring? Ob stet Gynecol 1990;76:1130-4. American College of Obstetricians and Gynecologists. Intrapartum fetal heart rate monitoring. Washington: American College of Obstetricians and Gynecologists, 1989 Sept; Technical bulletin no 132. Organization for Obstetric, Gynecologic, and Neonatal Nurses. Fetal heart rate auscultation. Washington: Organization for Obstetric, Gynecologic, and Neonatal Nurses, 1990 March. American Academy of Pediatrics and American College of Obstetricians and Gynecologists. Guidelines for perinatal care. 2nd ed. Washington: American Academy of Pediatrics and American College of Obstetricians and Gynecologists, 1988:67. Krebs HB, Petres RE, Dunn LJ. Intrapartum fetal heart rate monitoring. V. Fetal heart rate patterns in the second stage of labor. AM J OBSTET GYNECOL 1981;140:435-9. Reply
To the Editors: We appreciate the comments of Sand mire regarding our article about intrapartum monitoring with auscultation. Apparently, from their questions, they have misinterpreted our comments. Although the limits of my reply will not allow a line-by-line comparison of the Material and methods portion of our article with Sandmire's comments, I would say in general that we indeed followed the recommendations of The American College of Obstetricians and Gynecologists. An example is Dr. Sandmire's misunderstanding that a 1: 1 nurse/patient ratio is not necessary unless risk factors are present. The American College of Obstetricians and Gynecologists Technical Bulletin states quite clearly that "Such auscultation is usually performed during a contraction and for thirty seconds thereafter. AI: 1 nurse-patient ratio is required if auscultation is used as the primary technique of fetal heart rate surveillance" (emphasis added). We also believe that nursing experience was not a factor as the protocol section of our report clearly demonstrates. The gist of our argument is that if auscultation is used according to the strict guidelines noted in the Technical Bulletin, it is not often possible to use this technique as the primary
1079
means of surveillance unless the guidelines are violated. The authors also state that we misinterpreted their frequency of "late assessments" as 20% when it was actually only 2% of all assessments. The exact wording of Sand mire's statement is as follows: "Late auscultation occurred less than once per five patients auscultated in each of the first and second stages of labor." If all the patients received auscultation as their primary means of surveillance during both stages of labor and one of five of those patients had one or more "late auscultations," that appears to be nearer to 20% than to 2%. It doesn't make any difference whether the mean number of auscultations was 20 or 200; if you miss one, you simply miss it. As we all know, most plaintiffs' attorneys can definitely tell you when fetal damage occurred - it was when the nurse-physician was not auscultating and this violates the protocol in their labor and delivery suite. The authors question the inability to continue auscultation on the basis of recording requirements. Although Sandmire is correct that it may take < 5 seconds to record the fetal heart rate, there are other nursing duties that are necessary. One may need to rotate the patient back to her side, rearrange her coverings, answer questions that the patient and family have, respond to analgesic needs, ete. I don't know about the readers but our nursing personnel frequently address these issues, and sometimes this makes them late in recording data at specific time intervals; perhaps this is only a problem in Mississippi, but I don't think so. Sandmire does agree that electronic FHR monitoring is helpful in decreasing the liability risk when the strip is normal, but he says that a normal strip only occurs 9% of the time. It's odd that he uses a 1981 reference, which only has to do with the second stage of labor, to validate his point. In contrast, I think clinicians are very much aware that what we are really looking for by using electronic FHR monitoring are nonreassuring or worrisome signs that would make one consider ancillary diagnostic procedures or delivery. Although many strips have occasional decelerations or periods of less than average short-term variability, probably not more than 10% to 20% of assessments would qualify for these further considerations. In those electronic FHR monitoring strips (dependent on the response to maternal and in utero fetal resuscitation and other clinical factors) most obstetricians can use these data to document that fetal compromise is not occurring. Under current guidelines either auscultation or electronic fetal monitoring is appropriate for intrapartum FHR surveillance. Nevertheless, after some 20 years of experience with both types of assessment I remain unconvinced that auscultation offers the best method of assessing fetal health in utero. I believe auscultation is not as objective as FHR monitoring in assuring fetal health nor is it as helpful to the obstetrician in ruling out intrapartum asphyxia. Finally, given a permanent record generated by FHR monitoring, I believe provider liability is reduced when compared with auscultation. John C. Morrison, MD Department of Obstetrics and Gynecology, University. of MississiPPi Medical Center, 2500 N. State St., Jackson, MI 39216-4505