Chapter 12 Postpartum Assessment and Nursing Care Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 1 Immediate Postpartum Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 2 Objectives Define key terms listed. Describe the postpartum period. Explain the involution of the uterus and describe changes in the fundal position. Explain the cause of afterpains. Distinguish among the characteristics of lochia rubra, lochia serosa, and lochia alba. Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 3 Objectives (cont.) Explain how to assess the postpartum woman’s perineum. Describe two ways in which the fluid accumulated during pregnancy is eliminated during the postpartum period. Explain the importance of monitoring the vital signs during the first 24 hours postpartum. List three factors that influence urinary retention after delivery. Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 4 Postpartum Period Also called puerperium Six-week interval from childbirth to the return of the uterus and other organs to a prepregnant state Immediate postpartum: first 24 hours Early postpartum: first week Late postpartum: second to sixth weeks Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 5 Goals of Postpartum Care Assist and support the woman’s recovery to the prepregnant state and identify deviations from the norm Educate the mother about her own self-care and newborn feeding and care Promote bonding between newborn and family Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 6 Dangers in Immediate Postpartum Hemorrhage Hypovolemic shock Infection Uterine cavity easily accessible to microorganisms from exterior Placental attachment site is like an open wound Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 7 Clinical Pathway in Postpartum Period Nursing assessments Teaching Medical and nursing interventions Discharge Follow-up care for woman Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 8 Physiologic Changes in the Reproductive System and Nursing Interventions Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 9 Involution of the Uterus Begins after expulsion of placenta Placental site contracts to a size less than half of its original size immediately after birth Contractions cause uterine muscles to act like “living ligatures” and compress blood vessels Caused by sudden withdrawal of estrogen and progesterone Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 10 Involution of the Uterus (cont.) Release of proteolytic enzymes into endometrium Causes protein material within endometrial cells to break down into substances that are excreted in the urine Number of muscle cells does not change, only their size Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 11 Exfoliation Unique healing process that allows healing of placental site without scarring Necrotic tissue is sloughed off Reparative process ensures future fertilized ova will implant in an unscarred uterus Endometrial regeneration is complete within 16 days postpartum Placental regeneration is complete at 6 weeks postpartum Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 12 Uterus Immediately after birth weighs about 1000 g (2.2 lbs) Decreases to 500 g (1.1 lb) during first week postpartum By second week postpartum, weighs around 340 g (12 oz) Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 13 Factors That Can Slow Involution Prolonged labor Incomplete expulsion of placenta and membranes Anesthesia Previous labors Distended (full) bladder Blood clots Boggy uterus Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 14 Factors That Can Enhance Involution Uncomplicated labor and birth Breastfeeding Early, frequent ambulation Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 15 Cervix After birth it is soft By 18 hours postpartum, has regained its usual form Gradually closes around 2 weeks postpartum Never regains original appearance After pregnancy, os looks like a slit instead of a circle or dot Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 16 Descent of Uterine Fundus Usual progression of uterine descent into pelvis at about 1 cm/day Immediately after delivery, fundus typically at umbilicus or just below it By 10 days postpartum, uterus should not be abdominally palpable Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 17 Subinvolution of the Uterus Failure of the uterus to return to the prepregnant state Most common cause is retained placental fragments Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 18 Afterpains Intermittent uterine contractions Occur for the first 2 to 3 days postpartum Hormone oxytocin Strengthens uterine contractions Compresses blood vessels Infant suckling can cause afterpains Ibuprofen can be given Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 19 Lochia Postpartum vaginal discharge Contains Blood from placental site Particles of necrotic decidua Mucus Normally fleshy odor similar to menstrual flow Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 20 Lochia Rubra Heaviest during first 1 to 2 hours after delivery Initially bright red (lochia rubra) Lasts 1 to 3 days May contain small clots Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 21 Lochia Serosa Vaginal flow pales Becomes pink to brown after about 3 days Should not contain clots and can last up to 27 days in some women Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 22 Lochia Alba Typically by 10 days postpartum, vaginal discharge becomes yellow to white May continue on average to the 6th week postpartum Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 23 Estimating Lochial Flow Count number of pads being changed per hour Pads can be weighed (1 g = 1 mL blood) Check fundal firmness Document per facility protocol Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 24 Lochial Flow Teach mother that she may see an increase in lochia on rising due to pooling of fluids within the vagina Excessive lochia rubra early in postpartum may suggest bleeding due to retained placental fragments Recurrence of bleeding in 7 to 10 days suggests bleeding from placenta site but could also be normal sloughing Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 25 Lochial Flow (cont.) After 3 to 4 weeks, late bleeding may be caused by infection or subinvolution Continued lochia serosa or alba suggests infection (endometritis) and may also indicate fever, pain, or abdominal tenderness Lochia will have an offensive odor if infection is present Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 26 Vagina Appears edematous and bruised By week 3, resumes prepregnant appearance Rugae begin to reappear By week 6, has almost regained prepregnant form May notice dryness, which usually disappears when ovulation and menstruation return Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 27 Perineum Often edematous and bruised from delivery Assess for type and amount of vaginal discharge, unusual swelling, discoloration, healing of tissues, discomfort Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 28 Assessing Episiotomy Site REEDA scale Redness Edema Ecchymosis (bruising) Discharge Approximation of wound Healing overall takes around 6 weeks Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 29 Changes in the Musculoskeletal System Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 30 Muscles and Joints Relaxin hormone decreases Ligaments and cartilage of pelvis begin to return to prepregnant state Progesterone hormone decreases Muscle tone improves Woman can develop diastasis recti Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 31 Lower Extremities Homans’ sign May occur due to venous stasis If present, may be early sign of venous thrombosis Report immediately Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 32 Changes in the Cardiovascular System Women lose at least 200 to 500 mL of blood during vaginal delivery Twice as much during cesarean birth Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 33 Rapid Changes in Blood Volume Prevent hypovolemia Changes include Elimination of placenta Rapid reduction of size of uterus Increase of blood flow to vena cava Mobilization of body fluids accumulated during pregnancy Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 34 Excess Fluid Disposed of two ways Diuresis (increased excretion of urine) • Woman may have urinary output as high as 3000 mL/day Diaphoresis (profuse perspiration) Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 35 Blood Values First 72 hours, greater loss of plasma volume than RBCs Temporary rise in hematocrit and hemoglobin Normal levels return in 2 to 4 weeks postpartum Leukocytosis (WBC can be as high as 15,000/mm3 or higher) without infection Normal levels return within 10 days postpartum Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 36 Blood Coagulation Increased during pregnancy Fibrinogen levels return to normal within 2 weeks postpartum Increases risk of thrombosis formation Risk can be decreased by early and frequent ambulation Dyspnea and tachypnea hallmark signs of pulmonary embolus Varicose veins diminish Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 37 Orthostatic Hypotension Pelvic blood flow resistance decreases after delivery Woman’s blood pressure falls May complain of lightheadedness or dizziness or may even faint (pass out) Instruct woman to rise slowly to prevent this from occurring Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 38 Postpartum Diaphoresis Elimination of excess fluid through the skin Body’s way of getting rid of excess fluid accumulated during pregnancy Profuse diaphoresis occurs most often at night Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 39 Vital Signs Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 40 Temperature First 24 hours after delivery, temperature may rise to 38° C (100.4° F) Result of dehydration and exertion of labor Thereafter temperature should be in normal range If temperature still elevated, infection may have developed and should be reported Breast engorgement can cause a short-term elevation in temperature Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 41 Pulse In first 6 to 8 days Decreases to a rate of 50 to 60 beats/minute Elevated rate may indicate undue blood loss, infection, pain, anxiety, or cardiac disease Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 42 Blood Pressure Should remain stable after birth Decrease may indicate blood loss Elevation with a headache may indicate gestational hypertension that still needs to resolve in the postpartum period Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 43 Changes in the Urinary System Loss of muscle tone in the bladder During labor and delivery, urethra, bladder, and surrounding tissue may become edematous or traumatized Urination can be impeded by anesthetic agents Urinary output in the early postpartum period can be significantly high Close observation of I&O is essential Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 44 Urine Composition Mild proteinuria as result of uterine cell breakdown May test positive for acetone or ketones Lactosuria may occur in breastfeeding women Normal status returns about 4 weeks postpartum Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 45 Audience Response System Question 1 Glomerular filtration rate can remain high in the postpartum phase for up to: A. 2 weeks B. 4 weeks C. 6 weeks D. 8 weeks Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 46 Physiological Changes Postpartum Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 47 Objectives Discuss three factors that contribute to postpartum constipation. List two significant events that occur as a result of changes in the endocrine system. Explain the factors involved in the woman’s weight loss after birth. Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 48 Objectives (cont.) Interpret Rubin’s taking-in and taking-hold phases. Explain the psychological alteration called postpartum blues. Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 49 Changes in the GI System May have constipation postpartum due to Decreased peristalsis Stretched abdominal muscles Limited food or fluid intake Soreness and swelling of perineum or hemorrhoids Fear of pain Woman should have a bowel movement within 3 days postpartum Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 50 Fluid and Nutrition in Postpartum Period Eat three balanced meals a day Maintain adequate calcium and phosphorus intake If breastfeeding, high fluid and high fiber intake to reduce risk of constipation Increase calories by 500 per day if breastfeeding Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 51 Changes in the Nervous System Carpal tunnel syndrome may be lessened due to diuresis that occurs in postpartum period Headaches may continue for a while in women who experienced gestational hypertension Should be investigated Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 52 Changes in the Integumentary System Melanocyte-stimulating hormone (which causes hyperpigmentation) decreases rapidly after delivery Chloasma (mask of pregnancy) and linea nigra fade Spider nevi and palmar erythema due to increased estrogen levels disappear Striae gravidarum (stretch marks) gradually fade, but do not totally disappear Hair growth slows; may experience some hair loss Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 53 Changes in the Endocrine System Estrogen and progesterone levels decrease after expulsion of placenta Prepregnant levels If bottle-feeding, returns in about 3 weeks If breastfeeding, normal levels take longer First menses is usually anovulatory, but birth control should still be used Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 54 Prolactin and Oxytocin Prolactin promotes milk production and ejection Oxytocin triggers milk ejection when infant sucks on nipple Stimulates alveolar cells of breast Also stimulates uterine contractions Day 3 postpartum, breast engorgement can occur Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 55 Breast Engorgement Primarily caused by temporary congestion of veins and lymphatics, not milk accumulation Spontaneously resolves within 24 to 36 hours Supportive bra should be worn for 72 hours; ice packs and mild analgesics may be used Milk production ceases within a few days to a week Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 56 Resumption of Ovulation and Menstruation Nonlactating woman Lactating woman Ovulation may return within 1 month Menstruation usually resumes within 3 months Ovulation may return within 1 month Menstruation usually resumes within 6 months Menstruation may be heavy initially Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 57 Weight Loss Immediately after delivery weight decreases by 4.5 to 5.4 kg (10 to 12 lbs) Accounts for loss of fetus, placenta, and amniotic fluid Additional loss of 2.3 kg (5 lbs) due to diuresis and diaphoresis 2.3 to 3.2 kg (5 to 7 lbs) of fat stored during pregnancy for lactation Takes about 6 months to use if breastfeeding Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 58 Psychological Changes and Nursing Interventions Mood swings common Related to rapid decline of estrogen and progesterone Maternal role and personal insecurity may also contribute Maternal adaptation takes place in phases Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 59 Taking-In Phase Begins immediately after birth and lasts up to 2 days postpartum Passive, dependent behavior Focuses on her own needs and health of newborn Repeatedly reviews labor and delivery experience Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 60 Taking-Hold Phase Ready to assert independence Initiates independent care of her newborn Often becomes exhausted in new role and verbalizes anxiety about it Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 61 Letting-Go Phase Assumes position in home and new maternal role Demands may lead to mild depression Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 62 Attainment of Maternal Role Learns mothering behaviors Becomes comfortable with identity as mother Bond between newborn and mother forms Occurs in four stages Anticipatory Formal Informal Personal Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 63 Interference with Maternal Role Attainment Woman’s maturity level Minimum exposure of mother to baby in days after birth Lack of support system Ill health Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 64 Postpartum Blues 70% of women experience this Generally starts a few days after birth and lasts around 10 days Characterized by Tearfulness Insomnia Lack of appetite Feeling of being disappointed Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 65 Teaching the Postpartum Woman Relaxation techniques Increasing confidence in self-care and newborn care Promote communication between woman and partner Postpartum support group referral that may be in community Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 66 Audience Response System Question 2 Ovulation and menstruation typically resumes: A. Nonlactating woman B. Lactating woman Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 67 Care Management After Delivery Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 68 Objectives Demonstrate three ways to prepare the sibling for the new family member. Present two ways to encourage parentnewborn attachment. Explain why early ambulation is encouraged. Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 69 Objectives (cont.) Review the importance of Kegel (perineal tightening) exercises. Describe five danger signs that the woman should report after discharge from the hospital. Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 70 Care Management After Delivery Nursing assessment per facility protocol For mother, includes vital signs, fundal location and consistency, amount of bleeding Infant may be put to breast Infant is assessed on arrival in the newborn nursery Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 71 Care Plan Begins by using every contact with mother to fulfill teaching and learning goals Assist mother and family in learning about self-care and care of newborn Family and siblings can visit Mother encouraged to ask questions Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 72 Cultural Considerations Rituals, taboos, and traditions need to be respected Birth control practices vary and must be considered when discussing family planning Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 73 Postpartum Check: BUBBLE-HE Breasts Uterus Bladder Bowel Lochia Episiotomy (perineum) Homans’ sign Emotions (psyche) Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 74 Ambulation Early and often Reduces risk of thrombus formation and infection Advise woman to ask nurse for assistance when she is first getting out of bed May experience orthostatic hypotension Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 75 Postpartum Chill Uncontrollable, usually after birth Cause is unknown May be related to nervous response or to vasomotor changes If chill is without fever, there is no clinical significance (i.e., infection) Cover woman with warm blankets Reassure woman that this is a normal response Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 76 Promoting Comfort Episiotomy Hemorrhoids Afterpains Breast engorgement Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 77 Nursing Interventions Application of cold or heat to the perineum Sitz bath—provides comfort, promotes healing, reduces incidence of infection Should not last longer than 20 minutes Topical anesthetic application Wait to apply peripad for 1 to 2 minutes to prevent medication from being absorbed into pad Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 78 Family Adjustment and Development of Attachment Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 79 Partner Bonding Partner should be included in all teaching sessions involving newborn care and feeding Bonding begins prenatally when father or partner feels fetus move or hears the heartbeat Engrossment is shown by holding, studying, and touching infant Adjustment and transition occur when partner is able to increase interaction with newborn and understands that time will be set aside for partner interaction Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 80 Sibling Adjustment Depends on age and development Younger siblings may consider newborn as competition May see behaviors such as Regression Jealousy Frustration Special time should be set aside for parents to give to older siblings Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 81 Grandparent Involvement Level of involvement depends on proximity Parenting practices change from one generation to next May bring conflict in child-rearing between parents and grandparents Attending grandparenting classes is encouraged Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 82 Promoting Parent-Newborn Bonding Bonding and attachment processes produce affectionate and emotional commitment between two individuals Touch Voice pitch (a high pitch causes infant to become more alert and turn toward voice) Progresses over time Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 83 Early Discharge Planning and Health Promotion Greatest need is education Mother must know How to prevent infection Danger signs to report for herself and her newborn Nurse provides education on how to care for newborn and then observes parents to see if additional education is needed Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 84 Discharge Teaching Can be provided through Video/DVD Pamphlets Return demonstrations Consultants, such as La Leche League for breastfeeding Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 85 Resumption of Normal Activity Increase activities gradually and avoid fatigue Most can resume all activities within 4 to 5 weeks postpartum Cultural factors also determine when normal activities can be resumed Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 86 Resumption of Sexual Intercourse Can be safely resumed when lochia has ceased, episiotomy has healed, and woman feels ready Usually takes 2 to 6 weeks First intercourse may be uncomfortable Partly attributed to vaginal dryness and diminished vaginal lubrication Breastfeeding woman may have milk spurts during orgasm due to release of oxytocin Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 87 Postpartum Fatigue Overwhelming sustained sense of exhaustion and decreased capacity for physical and mental work May persist for more than a year after delivery Early postpartum fatigue may be due to labor, hormone changes, wound healing, establishment of breast milk Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 88 Postpartum Fatigue (cont.) Factors contributing to continued fatigue Continuing sleep difficulties Child care responsibilities Lack of assistance Nurse should provide anticipatory guidance to woman and her partner on how to lessen some of these factors Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 89 Family Planning Provide couple with options (see Chapter 19) Stress that ovulation often resumes before first menses, and pregnancy can occur Oral contraceptives can be started 2 to 3 weeks after delivery if not breastfeeding Progestin-only for birth control Enhances quality and duration of lactation Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 90 Postpartum Exercises Hormonal effects on connective tissue are not reversed until ~6 weeks postpartum Risk of injury still present until after this time frame With normal, uneventful delivery, on first or second day, woman can Deep breathe Perform abdominal exercises, Kegel exercises, pelvic tilts Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 91 Kegel Exercises Strengthen and tone muscles of pelvic floor May help Decrease stress incontinence Speed recovery Increase sexual response Advised to do throughout life Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 92 Pelvic Tilt Assists with postural alignment and relieves strain on lower back Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 93 Rubella Vaccine Woman with a serum titer of 1:10 or less is given rubella vaccine in the postpartum period Stress with woman that she is not to become pregnant for at least 3 months after the vaccine has been given Can cause birth defects Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 94 RHo(D) Immune Globulin (RhoGAM) Given to women who are Rh negative and meet specific criteria Should receive within 72 hours after delivery Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 95 Signs of a Distended Bladder Discuss the signs of a distended bladder in a postpartum woman: Fundus: ____________ Bladder: ____________ Voiding: ____________ Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 96 Review Key Points Copyright © 2012, 2008 by Saunders, an imprint of Elsevier Inc. 97