Editorials - September 15, 2000 - American Family Physician

Editorials

Vacuum Extraction: A Necessary Skill

MARK DEUTCHMAN, M.D.
University of Colorado Health Sciences Center,
Denver, Colorado

See article in this issue.

Vacuum extraction is an important maternity care skill for family physicians. Nationally, 82 percent of family physicians delivering infants have hospital privileges to perform vacuum extraction, which is nearly double the 44 percent who have privileges to assist delivery with forceps.¹The ability to perform operative vaginal delivery using forceps or vacuum is important to those who provide maternity care because as many as 25 percent of nulliparous women have operative vaginal delivery.² Increasing use of operative vaginal delivery is one means suggested by the U.S. Department of Health and Human Services (HHS) to help reduce cesarean delivery rates.³

TABLE 1
Mnemonic for Vacuum Extraction

A Ask for help, Address the patient, and is Anesthesia needed.

B Bladder empty.

C Cervix must be completely dilated.

D Determine position and think shoulder dystocia.

E Equipment and Extractor ready.

F Apply the cup over the sagittal suture and in relation to the posterior Fontanelle.

G Gentle traction in the proper axis.

H Halt traction when the contraction is over; Halt the procedure if you have had disengagement of the cup three times, have had no progress in three consecutive pulls or three "pop-offs."

I Evaluate for Incision (episiotomy) when the head is being delivered.

J Remove the cup after the Jaw is delivered.

Used with permission from the American Academy of Family Physicians. Advanced life support in obstetrics (ALSO). Leawood, Kan.: American Academy of Family Physicians.

Vacuum extraction may appeal to many family physicians perceiving modern, semirigid or soft cups as less invasive, less dangerous to mother and infant, and simpler to use than forceps. The family practice community has embraced vacuum extraction with informative articles such as the one by Putta and Spencer⁴ in this issue of American Family Physician, by including the technique as one of the major skill components in the Advanced Life Support in Obstetrics (ALSO) course⁵ offered by the American Academy of Family Physicians (AAFP) and by including workshops in the annual Family Centered-Maternity Care course, also offered by the AAFP.⁶ Recent survey data suggest that vacuum extraction is also gaining favor among obstetrician-gynecologists who have traditionally favored forceps, particularly among those more recently trained, and for midpelvic application.⁷ More than 10 years ago, a widely quoted article in the obstetrics-gynecology literature declared, "The obstetric vacuum extractor is the instrument of first choice for operative vaginal delivery."⁸

Despite the enthusiasm for operative vaginal delivery in general as an alternative to cesarean delivery and for vacuum extraction in particular, many maternity care clinicians and members of the public have been alarmed by a "dark side" of vacuum extraction. This dark side is fetal injury--subgaleal hemorrhage and intracranial hemorrhage--which can be fatal. The HHS published a Public Health Advisory⁹ from the U.S. Food and Drug Administration about this problem in 1998 that was directed to a broad list of recipients including "obstetricians, pediatricians, family practitioners, hospital risk managers and hospital OB-GYN departments." In 1999, the American Broadcasting Company produced and aired a segment on its "20/20" television news program¹⁰ that graphically detailed the tragic results of subgaleal hemorrhage in two infants and pointed out to professionals some of the pitfalls and technique errors associated with vacuum extraction.

Many texts and articles associate physician technique errors with increased incidence of fetal injury. These errors include cup misapplication, excessive duration of vacuum application, sudden disengagement ("pop-offs"), pulling in the wrong axis and rocking the head. Avoiding these errors is certainly important, but a recent report documents that abnormal labor is an important underlying risk factor for intracranial hemorrhage, whether the baby is delivered by vacuum extraction, forceps or by the cesarean route.¹¹

Against this cautionary backdrop, it is prudent to look for evidence-based answers to a variety of questions that arise during the use of vacuum extraction and that go beyond or supplement those addressed in the article by Putta and Spencer.⁴A mnemonic developed for the ALSO course provides a useful summary of proper techniques (see the accompanying table).⁵

Where should the cup be applied on the fetal head? Whether the infant presents with the occiput anterior, posterior or some degree of transverse, major causes of difficulty with the second stage of labor and failure of assisted vaginal birth are deflexion of the fetal head and acyclitism. Goals of cup positioning are, therefore, maintenance or improvement of flexion and cyclitism. To optimize these factors, the cup should be placed on the "flexion point," the center of which is located directly over the sagittal suture and about 6 cm behind the anterior fontanelle (Figure 1). In occiput transverse positions, autorotation of the fetal head occurs during assisted delivery without any intentional twisting motion by the operator.

FIGURE 1. The flexion point is located directly on the sagittal suture, 6 cm behind the anterior fontanelle regardless of head position. When the vacuum extractor cup is centered over the flexion point, flexion and cyclitism are promoted. Placing the cup off to the side of the sagittal suture or closer to the anterior fontanelle promotes acyclitism, deflexion and cup disengagement.

How should suction be applied for best effectiveness and safety? Many references state unequivocally that vacuum should be applied intermittently--on during contractions, off between contractions--and for a specified number of pulls, minutes or pop-offs. One randomized, controlled trial¹² using the M-type cup helps answer this question, showing no difference in outcome or complications whether suction is applied continuously or intermittently, and whether or not some traction is held between contractions to prevent loss of station.

The length of vacuum application and number of pulls before abandonment have also been suggested as 20 to 30 minutes and three pulls, respectively. Evidence for these guidelines have previously been anecdotal, but one randomized study¹³ and one observational study¹⁴ show that longer times from initial application to delivery and off-midline cup application are the most important factors correlating positively with an increase in cephalohematomas, although these lesions were mostly of cosmetic significance. The break points for increased scalp injury in these studies were five and 10 minutes of application-to-delivery time, respectively, and the number of pulls required was three or fewer in about 90 percent of cases. This suggests that the "20 to 30 minute" and "three pulls" guidelines seem prudent, even generous, although if steady progress is being made and delivery is imminent, there is no reason to arbitrarily proceed to cesarean delivery. Similarly, if no progress is felt, it probably does not matter how many pulls or minutes have elapsed, the procedure should be terminated.

No study researched for this editorial had sufficient data on pop-offs from which to draw conclusions, although common sense would suggest that if the cup keeps popping off, the operator should be alerted to error in technique, equipment failure or significant cephalopelvic disproportion.

In what direction should traction be applied to aid delivery and prevent pop-offs? Traction should be applied along the axis of the pelvic curve and to maintain flexion of the fetal head. This means that the higher the station, the more "downward" toward the patient's rectum the axis of traction. As the head descends and crowns, the axis should be extended upward toward the patient's abdomen (Figure 2). If the cup has a central stem, the stem should be kept perpendicular to the plane of the cup opening to keep an edge from disengaging. Placing a finger against the cup can give early warning of impending pop-off so traction can be decreased.

FIGURE 2. The axis of traction is more toward the rectum for higher head stations. As the head descends and crowns, traction is directed increasingly upward along the pelvic curve and autorotation of the head occurs.

How should patients be counseled? Except in emergency cases of severe maternal or fetal distress, there is usually time to counsel the parents about the purpose, procedure, hazards and alternatives. It is also important to discuss what will be done if the vacuum procedure is not successful, including proceeding to cesarean delivery. One concern is whether or not a failed trial of vacuum assist will worsen the infant's outcome when cesarean delivery is performed. The data are conflicting. One retrospective study¹⁵ showed no worse outcome for infants delivered by cesarean after failed vaginal assist than for other infants delivered by cesarean during the second stage of labor. However, a much larger study¹¹ of hospital discharge records showed otherwise. The odds ratio for subdural or cerebral hemorrhage was 2.5 for cesarean delivery performed during labor without preceding attempts at operative vaginal delivery but increased to 8.8 when failed operative vaginal delivery preceded cesarean delivery.¹¹ Presentation of this information might cause some patients to forgo vacuum or forceps attempts and proceed directly to cesarean delivery. A useful discussion of risks and a sample consent form can be found at the following Web sites:http://www.obgmanagement.com/cutrisk/vacuum.html and http://www.obgmanagement.com/forms.html.

Where can I get more information? A thorough and well-illustrated handbook and CD-ROM about vacuum extraction are available from Vacca Research Pty Ltd. at their Web site: http://www.vaccaresearch.net.au. The cost of the handbook is $35 plus postage and the cost of the CD-ROM is $210 plus postage for personal use and $310 plus postage for institutional use. Instruction and hands-on practice in vacuum extractor technique on mannequins is part of the ALSO course of the AAFP.⁵

Mark Deutchman, M.D., is a professor in the Department of Family Medicine at the University of Colorado Health Sciences Center, Denver.

Address correspondence to Mark Deutchman, M.D., University of Colorado Health Sciences Center, Department of Family Medicine, Campus Box B155, 1180 Clermont St., Denver, CO 80220, (email: mark.deutchman@uchsc.edu).

REFERENCES

Practice profile I survey, May 1998. Facts about family practice, table 32A. Leawood, Kan.: American Academy of Family Physicians.

Drife JO. Choice and instrumental delivery. Br J Obstet Gynaecol 1996;103:608-11.

Healthy People 2000: national health promotion and disease prevention objectives: full report with commentary. Washington, D.C.: Government Printing Office, 1990:378. DHHS publication no. 91-50212.

Putta LV, Spencer JP. Assisted vaginal delivery using the vacuum extractor. Am Fam Physician 2000;62: 1316-20.

Damos JR, Koller WS. Vacuum extraction and forceps. In: Advanced life support in obstetrics course syllabus. 4th ed. Leawood, KS: American Academy of Family Physicians.

Family centered-maternity care course. Leawood, Kan.: American Academy of Family Physicians.

Bofill JA, Rust OA, Perry KG, Roberts WE, Martin RW, Morrison JC. Operative vaginal delivery: a survey of fellows of ACOG. Obstet Gynecol 1996;88: 1007-10.

Chalmers JA, Chalmers I. The obstetric vacuum extractor is the instrument of first choice for operative vaginal delivery. Br J Obstet Gynaecol 1989; 96:505-6.

Office of Surveillance and Biometrics. FDA public health advisory: need for caution when using vacuum assisted delivery devices. Rockville, Md.: U.S. Food and Drug Administration, May 21, 1998.

Vacuum births. ABC News 20/20, January 29, 1999 (Segment 3). New York, N.Y.: American Broadcasting Company, Inc.

Towner D, Castro MA, Eby-Wilkens E, Gilbert WM. Effect of mode of delivery in nulliparous women on neonatal intracranial injury. N Engl J Med 1999; 341:1709-14.

Bofill JA, Rust OA, Schorr SJ, Brown RC, Roberts WE, Morrison JC. A randomized trial of two vacuum extraction techniques. Obstet Gynecol 1997; 89:758-62.

Bofill JA, Rust OA, Devidas M, Roberts WR, Morrison JC, Martin JN Jr. Neonatal cephalohematoma from vacuum extraction. J Reprod Med 1997;42:565-9.

Teng FY, Sayre JW. Vacuum extraction: does duration predict scalp injury? Obstet Gynecol 1997;89: 281-5.

Revah A, Ezra Y, Farine D, Ritchie K. Failed trial of vacuum or forceps--maternal and fetal outcome. Am J Obstet Gynecol 1997;176(1 pt 1):200-4.

Weighing the Evidence for Vitamin Supplementation and CVD Prevention

ALEXANDRA ADAMS, M.D., PH.D.
GAIL UNDERBAKKE, R.D., M.S.
PATRICK E. MCBRIDE, M.D., M.P.H.
University of Wisconsin
Madison, Wisconsin

See article in this issue.

Many patients are frustrated by the mixed messages regarding vitamin supplements. They look to their physicians for guidance, but we often have insufficient or contradictory information because of the complexities of nutritional science and incomplete evidence. Health care recommendations must be based on carefully conducted scientific studies, and the strongest evidence regarding prevention and treatment comes from well-designed, randomized, controlled clinical trials; however, on what do we base our recommendations when clinical trials disagree?

In this issue of American Family Physician, recent clinical evidence regarding vitamin supplements and cardiovascular disease (CVD) prevention is reviewed.¹ The authors note that results from two recent clinical trials do not support the use of vitamin E supplementation to reduce CVD events^2,3; this is contrary to results from earlier trials that demonstrated a risk reduction from vitamin E supplementation.^4,5 They present again the lack of evidence supporting vitamin C and folate supplementation for reduction of CVD events¹ and conclude that the available evidence is insufficient to recommend vitamin supplementation for CVD prevention, relating this to a paucity of clinical trials rather than to negative outcomes.

We agree that results from trials do not support the use of vitamin C or beta carotene for reduction of CVD events; in fact, results from several of the trials of beta carotene revealed detrimental effects in the treated group.⁵ Folate, alone and/or in combination with vitamins B₆ and B₁₂, can reduce serum homocysteine that is associated with increased CVD risk; however, results from clinical trials have not been published regarding the role of folate in CVD event reduction.^6,7

Nevertheless, scientific evidence from observational, angiographic and clinical trials supports beneficial effects from vitamin E supplementation.^5,8 Results from several prospective studies revealed that higher vitamin E intakes from food or supplements were associated with reduced CVD risk.^9-11 This, plus other studies,^8,10 suggested that clinical trials should test the hypothesis that vitamin E intake could decrease CVD events. The Cambridge Heart Antioxidant Study⁴ results showed that supplementation of vitamin E from natural sources resulted in impressive reductions in non-fatal myocardial infarctions in patients with known CVD. This study was the first to test higher doses of vitamin E (400 and 800 IU) in contrast to studies that used lower doses and synthetic vitamin E.^4,5 Because of the theoretical benefits and the results from positive studies, other studies were conducted to test the effects of vitamin E supplements in preventing CVD. The results revealed no significant benefits or harm.^2,3

The lack of congruence of vitamin E trial results is perplexing, but several explanations are possible. First, the Heart Outcomes Prevention Evaluation Study² included participants with complicated disease and diabetes, while other studies have included participants with only CVD or less risk factors. Vitamin E may not benefit patients with more advanced CVD. Second, the different biologic activities of these compounds, or their combination with other nutrients or foods, may influence their effect. For example, vitamin E consists of eight compounds in two classes (tocopherols and tocotrienols), and different studies used different forms of vitamin E. The type of fat and micronutrients consumed in a daily diet may affect overall risk and lower the effects of vitamin supplementation, such as that seen in the Mediterranean diet common in GISSI participants.³ Current vitamin trials will address the need for combining vitamins¹² because most observational studies tested vitamin combinations.

What can we conclude and what do we tell our patients at this point in time? As we suggested previously, all patients should be encouraged to eat a variety of foods, including healthy amounts of fruits, vegetables and whole grains, which contain important micronutrients consistently associated with reduced CVD risk.^5,13,14 Pearce and colleagues^1,5 agree with our position that available evidence argues against the use of beta carotene and is insufficient regarding vitamin C supplementation for CVD reduction. The controversy remains regarding vitamin E supplementation and secondary prevention of CVD. The two new vitamin E studies would reject a role for vitamin E.^2,3 However, as we have previously stated, vitamin E is not harmful at 400 to 800 IU per day and may possibly benefit patients for reasons other than CVD prevention (e.g., improving arterial function).⁵ We also believe that the lack of toxicity and low costs of folate and vitamin E (in doses of 400 IU or less) allow for patient and physician judgment until further data become available.^5-7 We propose that folate use for elevated homocysteine levels in patients at high risk for CVD is reasonable and safe.^6,7

Because of the widespread interest and the use of supplements by the public, physicians need to review the potential benefits and risks of vitamin supplements with patients and allow patients to decide for themselves. We eagerly await the outcomes of trials of vitamin supplements and antioxidants that are currently in progress in order to provide a more complete synthesis of clinical information to help guide our recommendations. Until then, we share the confusion and frustration of our patients when the available evidence is contradictory.

Alexandra Adams, M.D., Ph.D., is an associate professor in the Department of Family Medicine at the University of Wisconsin, Madison.

Gail Underbakke, R.D., M.S., is a distinguished senior dietitian in the Department of Medicine (Cardiovascular Section) and Family Medicine at the University of Wisconsin, Madison.

Patrick E. McBride, M.D., M.P.H., is a professor in the Department of Medicine (Cardiovascular Section) and Family Medicine at the University of Wisconsin, Madison.

Address correspondence to Alexandra Adams, M.D., Ph.D. University of Wisconsin, Department of Family Medicine, 777 S. Mills St., Madison, WI 53713.

REFERENCES

Pearce KA, Boosalis MG, Yeager B. Update on vitamin supplements for the prevention of coronary disease and stroke. Am Fam Physician 2000;62: 1359-66.

Yusuf S, Dagenais G, Pogue J, Bosch J, Sleight P. Vitamin E supplementation and cardiovascular events in high-risk patients. The Heart Outcomes Prevention Evaluation Study Investigators. N Engl J Med 2000;342:154-60.

Dietary supplementation with n-3 polyunsaturated fatty acids and vitamin E after myocardial infarction: results of the GISSI-Prevenzione trial. Lancet 1999;354:447-55.

Stephens NG, Parsons A, Schofield PM, Kelly F, Cheeseman K, Mitchinson MJ. Randomised controlled trial of vitamin E in patients with coronary disease: Cambridge Heart Antioxidant Study. Lancet 1996;347:781-6.

Adams AK, Wermuth EO, McBride PE. Antioxidant vitamins and the prevention of coronary heart disease. Am Fam Physician 1999;60:895-904.

Stein JH, McBride PE. Hyperhomocysteinemia and atherosclerotic vascular disease: pathophysiology, screening, and treatment. Arch Intern Med 1998; 158:1301-6.

Fallest-Strobl PC, Koch DD, Stein JH, McBride PE. Homocysteine: a new risk factor for atherosclerosis. Am Fam Physician 1997;56:1607-12,1615-6.

Diaz MN, Frei B, Vita JA, Keaney JF Jr. Antioxidants and atherosclerotic heart disease. N Engl J Med 1997;337:408-16.

Kushi LH, Folsom AR, Prineas RJ, Mink PJ, Wu Y, Bostick RM. Dietary antioxidant vitamins and death from coronary heart disease in postmenopausal women. N Engl J Med 1996;334:1156-62.

Stampfer MJ, Hennekens CH, Manson JE, Colditz GA, Rosner B, Willett WC. Vitamin E consumption and the risk of coronary disease in women. N Engl J Med 1993;328:1444-9.

Rimm EB, Stampfer MJ, Ascherio A, Giovannucci E, Colditz GA, Willett WC. Vitamin E consumption and the risk of coronary heart disease in men. N Engl J Med 1993;328:1450-6.

Hercberg S, Galan P, Preziosi P, Roussel AM, Arnaud J, Richard MJ, et al. Background and rationale behind the SU.VI.MAX Study, a prevention trial using nutritional doses of a combination of antioxidant vitamins and minerals to reduce cardiovascular diseases and cancers. SUpplementation en VItamines et Mineraux AntioXydants Study. Int J Vitam Nutr Res 1998;68:3-20.

Tribble DL. AHA Science Advisory. Antioxidant consumption and risk of coronary heart disease: emphasis on vitamin C, vitamin E, and beta-carotene: a statement for healthcare professionals from the American Heart Association. Circulation 1999;99:591-5.

de Lorgeril M, Salen P, Martin JL, Monjaud I, Delaye J, Mamelle N. Mediterranean diet, traditional risk factors, and the rate of cardiovascular complications after myocardial infarction: final report of the Lyon Diet Heart Study. Circulation 1999;99:779-85.

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