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Critical Care Obstetrics part 4 doc

Critical Care Obstetric Nursing
19
medical personnel updated on the patient ’ s progress on a regular
basis.
Approximately 5 hours after initiation of the oxytocin infu-
sion, nursing assessment of maternal status revealed diminished
urinary output for 2 consecutive hours. In addition, the patient
complained of new - onset shortness of breath and a cough.
Auscultation of the lungs revealed the presence of crackles bilater-
ally. Vital signs included a blood pressure of 100/61, a normal
sinus rhythm of 82, and arterial oxygen saturation (S
a
O
2
) of 94%
on room air. Regular uterine contractions were noted every
2 – 4 min, moderate to palpation, and uterine resting tone was not
consistently relaxed to palpation. Assessment of fetal status
revealed a normal baseline rate, no FHR accelerations, and the
onset of repetitive FHR decelerations. The CCOB nurse inter-
preted these fi ndings as indicative of an adverse change in mater-

nal and fetal status. Nursing interventions were initiated including
administration of supplemental oxygen by mask, elevation of the
head of the patient ’ s bed, lateral displacement of the uterus, dis-
continuation of the oxytocin infusion and prompt notifi cation of
the CCOB physician. The physician ordered that the oxytocin
infusion remain off until the hemodynamic and oxygenation
status of the patient could be further assessed. A fi beroptic pul-
monary artery catheter with capability of continuous mixed
venous oxygen saturation (SvO
2
) monitoring was inserted via the
right internal jugular vein without complications. Initial maternal
hemodynamic and oxygen transport assessment data are pre-
sented in Table 3.3 . Fetal heart rate and uterine activity noted on
the EFM tracing at the time the decision was made to initiate
invasive hemodynamic monitoring, and after initial maternal
hemodynamic and oxygen transport data were obtained are pre-
sented in Figures 3.1 and 3.2 respectively.
Interpretation by the nurse of initial hemodynamic data indi-
cated the patient had a signifi cantly low cardiac output (CO).
Analysis of the determinants of cardiac output revealed a high left
preload, high right afterload, and signifi cantly impaired left ven-
tricular contractility. Assessment by the nurse of the pulmonary
artery waveform revealed the presence of large V waves. The exact
reason for all V - wave abnormalities is not always clear. Under
most circumstances, the regurgitation of blood into the atrium
during ventricular systole or a non - compliant atrium accounts
for most large V waves. However, if the V waves appear to increase
in a patient with severe left ventricular dysfunction, an acute
episode of failure may be imminent. Interpretation of oxygen
transport data indicated the patient also had a signifi cantly low
oxygen delivery (DO
2
). Analysis of determinants of oxygen deliv-
ery indicated the primary cause of the patient ’ s critically low DO
2

was her low cardiac output. The mixed venous oxygen saturation
(SvO
2
), indicative of oxygen saturation of hemoglobin returned
to the heart via the venous system, was signifi cantly low for an
obstetric patient. Most likely this was related to the critically low
cardiac output state. The oxygen extraction ratio, an expression
of the balance between oxygen supply and demand, was signifi -
cantly elevated, thus indicative of diminished oxygen reserve.
Interpretation of FHR data included a normal baseline rate,
complicated by a postoperative myocardial infarction (MI).
Subsequent care included cardiac rehabilitation with exercise and
medications to optimize cardiac function. Echocardiograms per-
formed during the period of cardiac rehabilitation revealed the
presence of persistent decreased left ventricular dysfunction and
mild pulmonary hypertension.
Her obstetric history was signifi cant for an unplanned preg-
nancy which occurred approximately 1 year following her CABG
and MI. She decided to undergo termination of the pregnancy
after consultation with a cardiologist and perinatologist. Less
than a year later, she presented at 9 weeks estimated fetal gesta-
tional age (EGA) for consultation with a perinatologist. She was
subsequently referred to a perinatologist at a local tertiary care
center. Initial evaluation included an echocardiogram which
indicated persistent moderate to severe left ventricular dysfunc-
tion, an ejection fraction between 25 and 30%, and elevated pul-
monary artery pressures. The consultation included a thorough
discussion with the patient and her husband of the potential risk
of morbidity and mortality associated with continuation of the
pregnancy, as well as components of a multidisciplinary plan of
care should continuation of the pregnancy be desired. Both the
patient and her husband verbalized a strong desire to continue
the pregnancy. Thus, prenatal care continued, without develop-
ment of additional maternal or fetal complications.
She was admitted to the CCOB service at 39 weeks gestation
for planned induction of labor and vaginal delivery. Any decision
to perform a cesarean section would be based on development
of obstetric indications. Maternal and fetal assessment fi ndings
at the time of admission were all reassuring. Occasional uterine
contractions were noted and her cervix was approximately
1 cm dilated and long. On the evening of admission, the induc-
tion process was started with the insertion of a Foley catheter
into the cervix and the bulb infl ated. A neonatologist met with
the patient, her husband, and other family members to answer
questions and reinforce the plan of care for the baby. Maternal
and fetal assessment fi ndings throughout the night remained
reassuring.
The following morning, an intravenous infusion of oxytocin
was initiated. Regional anesthesia via epidural block was
initiated, after administration of an intravenous crystalloid bolus.
Monitoring techniques included continuous maternal electrocar-
diogram (ECG) with the ability to monitor two leads (II and V
5
)
simultaneously, to detect myocardial ischemia or dysrhythmias.
An arterial catheter was utilized for continuous blood pressure
assessment and access for obtaining blood samples. Hourly
assessment of both intake and output, continuous arterial oxygen
saturation monitoring, and auscultation of breath sounds were
part of the nursing plan of care. Continuous electronic monitor-
ing of the FHR and uterine activity was also utilized. Equipment
for invasive hemodynamic and oxygen transport monitoring had
been assembled, prepared, and available at the bedside. In addi-
tion, necessary equipment and resources for delivery and imme-
diate care of the baby were made available in the patient ’ s room.
The charge nurse in labor and delivery kept neonatal nursing and
Chapter 3
20
Figure 3.1 Case example. Fetal heart rate and uterine activity at the time the decision was made to initiate invasive hemodynamic monitoring.
Table 3.3 Case example. Initial maternal hemodynamic and oxygen transport
data following initiation of invasive hemodynamic monitoring.
Maternal assessment fi ndings

Vital signs

Blood pressure 71/31 mmHg
Heart rate 75
Respiratory rate 26
S
a
O
2
97%
SvO
2
55%

Hemodynamic values

CVP 2 mmHg
PAP 71/27 mmHg
PCWP 24 mmHg
CO 3.2 L/min
CI 2.0 L/min/m
2

SVR 1037 dyne/s/cm
5

PVR 518 dyne/s/cm
5

LVSWI 7 g/m
2


Oxygen transport values

C
a
O
2
15 mL/dL
CvO
2
9 mL/dL
DO
2
480 mL/min
V O
2
192 mL/min
O
2
ER 40%
CVP, central venous pressure; PAP, pulmonary artery pressure; PCWP, pulmonary
capillary wedge pressure; CO, cardiac output; CI, cardiac index; SVR, systemic
vascular resistance; PVR, pulmonary vascular resistance; LVSWI, left ventricular
stroke work index.
C
a
O
2
, arterial oxygen content; CvO
2
, venous oxygen content; DO
2
, oxygen
delivery; VO
2
, oxygen consumption; O
2
ER, oxygen extraction ratio.
absence of FHR accelerations, and the presence of persistent FHR
decelerations with each uterine contraction, despite discontinu-
ation of oxytocin.
Nursing diagnoses, based upon interpretation of these assess-
ment fi ndings, included decreased cardiac output, impaired gas
exchange, impaired maternal and fetal oxygen transport, activity
intolerance related to inadequate oxygen reserve, and anxiety.
Desired outcomes included optimization of cardiac output,
maternal and fetal oxygen transport and gas exchange, optimiza-
tion of oxygen reserve, and reduction in the level of patient
anxiety.
To develop a plan of care, the CCOB physician was contacted
and the assessment fi ndings and nursing diagnoses were dis-
cussed. Collaboration resulted in a plan of care intended to
achieve the desired outcomes. Interventions to optimize cardiac
output focused on improvement of left ventricular contractility
and correction of the patient ’ s high left preload. Dobutamine was
administered by intravenous infusion for inotropic support. The
method of action is stimulation of beta receptors in the heart
muscles which increases contractility, thereby increasing stroke
volume and cardiac output. The initial dosage was 2.5 µ g/kg/min.
In the absence of an appreciable increase in SvO
2
, the dosage was
increased to 5.0 µ g/kg/min. Assessment of the ECG tracing
revealed no tachydysrhythmias or ventricular ectopy. Within 5
minutes following the change in the dobutamine dosage, the
continuous SvO
2
monitor indicated a signifi cant improvement.
Thus, hemodynamic and oxygen transport data were obtained
and are presented in Table 3.4 .
Evaluation of the patient ’ s response to interventions ensued.
Interpretation of these data indicates signifi cant improvement in
left ventricular contractility, normalization of left preload, and
improvement in cardiac output. In addition, oxygen delivery
increased signifi cantly which in turn increased the patient ’ s
Critical Care Obstetric Nursing
21
Figure 3.2 Case example. Fetal heart rate and uterine activity at the time initial maternal hemodynamic and oxygen transport data were obtained.
oxygen reserve. Arterial oxygen saturation improved to 99% and
remained at that level following discontinuation of supplemental
oxygen by mask. Resolution of adventitious lung sounds as well
as oliguria was also noted. Subsequent fetal assessment fi ndings
are presented in Figure 3.3 . Interpretation of these data indicates
a normal baseline FHR, presence of accelerations and absence of
FHR decelerations. The frequency of uterine contractions was
every 2 ½ to 4 ½ minutes and mild to moderate upon palpation.
Uterine resting tone was also noted to be consistently relaxed
upon palpation. Collectively, these subsequent maternal and fetal
assessment fi ndings were considered reassuring.
The attending CCOB physician performed a digital vaginal
examination which revealed the cervix to be 3 cm dilated and soft.
An amniotomy was subsequently performed with clear fl uid
noted. An internal fetal ECG electrode was applied and an intra-
uterine pressure catheter inserted. The decision was made to
resume the oxytocin infusion, continue the dobutamine infusion,
and reassess maternal and fetal status in accordance with unit
guidelines. The plan of care was discussed with the patient, her
husband and family members. They remained with the patient in
accordance with the visitation policy within the labor and deliv-
ery unit. Their presence and support facilitated reduction in the
patient ’ s anxiety level.
As labor continued, both maternal and fetal status remained
reassuring, until the nurse noted an abrupt change in the FHR
tracing. Changes in the FHR tracing are presented in Figures 3.4
and 3.5 . Assessment of the tracing revealed the onset of variable
decelerations, caused by umbilical cord compression, which were
followed by a prolonged deceleration. Assessment of uterine
activity revealed no evidence of over stimulation. Findings
included the presence of contractions every 2 ½ to 3 minutes,
65 – 80 mmHg in intensity, lasting between 50 and 60 seconds,
with a normal uterine resting tone of approximately 20 mmHg.
Table 3.4 Case example. Maternal hemodynamic and oxygen transport data
following interventions.
Maternal assessment fi ndings

Vital signs

Blood pressure 127/75 mmHg
Heart rate 84
Respiratory rate 21
S
a
O
2
99%
SvO
2
75%

Hemodynamic values

CVP 3 mmHg
PAP 52/14 mmHg
PCWP 11 mmHg
CO 5.6 L/min
CI 3.6 L/min/m
2

SVR 1271 dyne/s/cm
5

PVR 228 dyne/s/cm
5

LVSWI 54 g/m
2


Oxygen transport values

C
a
O
2
16 mL/dL
CvO
2
129 mL/dL
DO
2
896 mL/min
V O
2
224 mL/min
O
2
ER 25%
CVP, central venous pressure; PAP, pulmonary artery pressure; PCWP, pulmonary
capillary wedge pressure; CO, cardiac output; CI, cardiac index; SVR, systemic
vascular resistance; PVR, pulmonary vascular resistance; LVSWI, left ventricular
stroke work index.
C
a
O
2
, arterial oxygen content; CvO
2
, venous oxygen content; DO
2
, oxygen
delivery; VO
2
, oxygen consumption; O
2
ER, oxygen extraction ratio.
Chapter 3
22
Figure 3.3 Case example. Fetal heart rate and uterine activity following interventions.
the CCOB nurse assessed the pulmonary capillary wedge pres-
sure, cardiac output and other routine vital signs. Assessment of
these fi ndings revealed no adverse change in maternal hemody-
namic status. Collaboration with the physician resulted in a plan
of care directed toward alleviating the cord compression. An
amnioinfusion was subsequently initiated during which a second
prolonged deceleration lasting 4 minutes was noted. The patient
was again repositioned and the amnioinfusion continued. Fetal
responses following these interventions are depicted in Figure 3.6 .
The FHR baseline remained normal, FHR variability was present,
variable decelerations continued but no further prolonged decel-
erations developed. Approximately 2 hours later, the patient ’ s
The nurse interpreted the prolonged deceleration as non - reassur-
ing and immediately initiated appropriate interventions. The
charge nurse was notifi ed of the need for immediate assistance
and was asked to notify the CCOB physician of the adverse
change in fetal status. The nurse performed a digital vaginal exam
which ruled out the presence of an umbilical cord prolapse. The
cervix was noted to be 4 cm dilated and 90% effaced. A second
nurse arrived and immediately began respositioning the patient
in order to decrease umbilical cord compression. The fi rst pro-
longed deceleration lasted 5 minutes and resolved following
maternal repositioning. To determine if the change in fetal status
might be related to a change in maternal hemodynamic status,
Figure 3.4 Case example. Adverse fetal heart rate changes during labor.
Critical Care Obstetric Nursing
23
Figure 3.5 Case example. Adverse fetal heart rate changes during labor (continued).
Figure 3.6 Case example. Fetal heart rate following amnioinfusion.
cervix was reassessed and found to be 8 – 9 cm dilated with the fetal
vertex at 0 station. Maternal and fetal status remained reassuring
until a signifi cant decrease in SvO
2
was noted during the second
stage of labor. Following evaluation by the physician, the decision
was made to provide assistance to expedite delivery. She subse-
quently had a forceps - assisted vaginal delivery of a baby girl.
Neonatal personnel were present to assess the baby and provide
necessary care. Apgar scores and cord blood gases were normal.
The baby was transferred to the transitional nursery for further
assessment, but a short time later was considered suffi ciently
Chapter 3
24
affi nity of oxygen to hemoglobin is decreased, in turn facilitating
oxygen diffusion and transport. The left shift in the fetal oxyhe-
moglobin dissociation curve increases the affi nity of oxygen to
fetal hemoglobin. Thus, an optimum environment is created for
maternal – fetal gas exchange.
Based on the theory of venous equilibration, it is apparent that
the uterine venous PO
2
is the major determinant of umbilical
venous PO
2
. The oxygen saturation of uterine venous blood is
affected by three variables: oxygen saturation of maternal arterial
blood, oxygen content of maternal blood, and uterine blood fl ow.
Any reduction in maternal P
a
O
2
thus decreases uterine venous
PO
2
and umbilical venous PO
2
.
Uterine contractions cause a reduction in uterine blood fl ow
secondary to a signifi cant increase in uterine vascular resistance.
In addition to the effect of uterine contractions, a number of
maternal conditions may impair oxygen delivery. In essence, any
condition that causes maternal uterine venous PO
2
to be reduced
will also result in decreased oxygen transport to the fetus.
For these reasons, it is especially important for the nurse to
frequently assess the hemodynamic and oxygen transport status
of the obstetric patient requiring mechanical ventilation. App-
ropriate interpretation by the nurse of assessment fi ndings is
critical. If a pregnant woman has diminished arterial oxygen
content because of anemia, decreased arterial oxygen saturation
(S
a
O
2
), or a low P
a
O
2
, or decreased cardiac output, catechol-
amines subsequently redistribute blood fl ow in favor of vital
maternal organ systems. Thus, alterations in uterine activity or
the fetal heart rate may be indicative of decreased oxygen trans-
port or perfusion. It is common to fi nd this dynamic process
illustrated at the bedside when assessment by the nurse of the
electronic fetal monitor (EFM) tracing reveals adverse changes in
maternal – fetal status. Initiation of appropriate nursing interven-
tions, including notifi cation of the physician of signifi cant assess-
ment fi ndings, is imperative. In the event that adverse changes in
maternal or fetal status persist, despite initiation of appropriate
interventions, or acute deterioration in maternal or fetal status
occurs, decisions regarding delivery of the fetus may be necessary.
Thus, the plan of care should provide for the capability to perform
emergent delivery via cesarean section should it become neces-
sary. In addition, the potential urgent need for appropriate per-
sonnel and resources to resuscitate and stabilize the newborn
should be anticipated and addressed in the plan of care.
In addition to physiologic concepts which provide a frame-
work for critical care obstetric nursing care, signifi cant psycho-
social principles should be incorporated in any plan of patient
care. Obstetric critical care can benefi t from data in the critical
care literature that address family and patient needs in a
critical care setting. Obstetric literature and extensive experience
in implementation of a family - centered approach to care of the
pregnant woman can also be used to identify the need for humane
care in an obstetric critical care setting [22,23] . Use of mechanical
ventilation subjects the obstetric patient to physical and psycho-
social stress. It is also a diffi cult time for the patient ’ s family and
support system. Concern for the condition of the pregnant
stable to be returned to labor and delivery to stay in the room
with the patient and her family.
Mechanical v entilation d uring p regnancy:
c ritical c oncepts for n ursing p ractice
General indications for the initiation of mechanical ventilation
include inadequate arterial oxygenation, inadequate alveolar
ventilation, and excessive respiratory workload. Complications
during pregnancy may cause respiratory or ventilatory failure
that necessitates mechanical ventilatory support. Such complica-
tions include severe pre - eclampsia or eclampsia, pulmonary
edema, pneumonia, sepsis, pulmonary embolism, neurological
insult, drug overdose, trauma, or aspiration. A thorough and
specifi c discussion of airway management in critical illness is
presented in Chapter 9 of this text. Guidelines for the medical
diagnosis of respiratory and ventilatory failure, criteria upon
which these diagnoses are based, modes of mechanical ventila-
tion, settings and goals, complications, and weaning techniques
are included in that chapter. Detailed discussions of disease pro-
cesses during pregnancy that may lead to respiratory failure are
presented elsewhere in this text.
Caring for the obstetric patient requiring mechanical ventila-
tion presents unique challenges to the healthcare team. Com-
prehensive discussion of specifi c nursing care issues related
to care of such patients is beyond the scope of this chapter.
Additional resources are available that address topics including
nursing diagnoses associated with care of the obstetric patient
requiring mechanical ventilation, assessment of ventilation and
oxygenation, airway care, strategies for prevention of nosocomial
infection, and psychosocial support [20,21] .
The following physiologic concepts are signifi cant and should
be incorporated in the framework for clinical nursing care of the
obstetric patient requiring mechanical ventilation. The nurse
should fi rst recall that numerous changes in the maternal respira-
tory system occur during pregnancy. These result from endo-
crine, physical and mechanical infl uences throughout pregnancy.
The net physiologic result is a decrease in maternal P
a
CO
2
to a
level less than half that of the fetus. This leads in turn to increased
bicarbonate excretion by the maternal kidneys. This compensa-
tory mechanism serves to maintain the maternal arterial pH
between 7.40 and 7.45. Thus, normal arterial blood gases during
pregnancy refl ect a state of compensated respiratory alkalemia.
Additional cardiovascular changes signifi cantly increase cardiac
output throughout pregnancy, with further increases noted
during labor, birth, and the immediate postpartum period.
Collectively, these alterations signifi cantly increase the rate of
oxygen delivery. Because of the high oxygen diffusion gradient
during pregnancy, oxygen diffuses from the maternal alveoli into
the maternal circulation, binding to red blood cells at a more
rapid rate. Oxygen is subsequently transported via the placenta
to fetal tissues. In addition, a right shift in the maternal oxyhe-
moglobin dissociation curve occurs during pregnancy. Thus, the
Critical Care Obstetric Nursing
25
fi ndings pertaining to the fetal heart rate (FHR) and uterine activ-
ity are presented in Figure 3.7 .
Interpretation by the nurse of initial hemodynamic data indi-
cated the patient had a signifi cantly low cardiac output (CO).
Analysis of the four determinants of cardiac output revealed a low
preload, high afterload, decreased left ventricular contractility,
and sinus tachycardia. Vasoconstriction and tachycardia most
likely represented compensatory mechanisms but were not suf-
fi cient to produce an adequate cardiac output. In addition,
decreased contractility of the left ventricle could be indicative of
impending heart failure. Interpretation of oxygen transport data
indicated the patient had a signifi cantly low oxygen delivery
(DO
2
). Analysis of determinants of oxygen delivery, in addition
to cardiac output, previously interpreted to be signifi cantly low,
revealed low arterial oxygen content (CaO
2
). In addition, oxygen
consumption (VO
2
) was low, possibly an indication of altered
organ system perfusion or impaired ability of organ systems to
extract oxygen, a condition referred to as delivery - dependent
oxygen consumption. During assessment of the patient ’ s respira-
tory status, the nurse noted the presence of tachypnea as well as
an apparent increased work of breathing. Lungs were clear bilat-
erally to auscultation. Interpretation of arterial blood gases
revealed an elevated pH, low P
a
CO
2
, and low P
a
O
2
, indicating
respiratory alkalemia. The presence of alkalemia produces a left
shift of the oxyhemoglobin dissociation curve. Such a shift
increases the affi nity or binding of oxygen to hemoglobin which
subsequently impairs the release of oxygen from hemoglobin for
woman as well as the well - being of the fetus produces stress and
anxiety for the patient and her family. Numerous reports have
shown that hospital admission for a critical illness may cause a
crisis within a family. Historically, visitation restrictions were
imposed in intensive care units (ICUs) to provide patients time
for rest. Visiting hours became so restrictive that many family
members felt they had lost their loved one with the admission to
the ICU. A result was confl ict between the duties of the critical
care nurse and the rights of the patient and family members.
The unique challenges inherent in providing care to this patient
population were presented in a study by Jenkins et al. which
described the characteristics and outcomes of obstetric patients
who required mechanical ventilation [24] . Data that were col-
lected included maternal demographics, medical condition that
necessitated mechanical ventilatory support, delivery status,
duration of ventilation, onset of parturition while receiving ven-
tilation, mode of delivery, and maternal and early neonatal mor-
bidity or death. A summary of results from the study is presented
in Table 3.5 . The three most frequent diagnoses that produced
complications which led to the need for mechanical ventilation
were pre - eclampsia or eclampsia (43%), labor or preterm labor
(14%), and pneumonia (12%). Overall, 43 of the 51 patients
(84%) included in the study were cared for in labor and delivery,
with care directed by a critical care perinatologist, a critical care
obstetric nurse, with consultations provided by other intensivists,
depending on the clinical picture.
Case e xample: Mechanical v entilation d uring p regnancy
The following case excerpts illustrate signifi cant clinical practice
concepts related to nursing care of a pregnant woman who
required mechanical ventilation. The case involved a 25 - year - old
primigravida at 33 weeks estimated fetal gestational age (EGA).
Her prenatal course had been uncomplicated until she developed
an upper respiratory infection. Despite outpatient treatment her
symptoms worsened and she was subsequently admitted to a local
community hospital where she was diagnosed with pneumonia.
She was refractory to the prescribed medical treatment regimen,
her condition worsened and a pulmonary consult was obtained.
The decision was made to transfer her to the medical intensive
care unit (MICU) for further care. Endotracheal intubation was
performed and a 7.0 Fr endotracheal tube was inserted without
complications. A volume - cycled ventilator was utilized for
mechanical ventilatory support. Central venous access was also
accomplished via the right internal jugular vein and a central
venous pressure (CVP) catheter was inserted. Following stabiliza-
tion, the decision was made to transport the patient to a tertiary
care center that had an established the CCOB service within the
labor and delivery unit. Following initial assessment by the CCOB
physician and CCOB nurse, the decision was made to replace the
CVP catheter with a fi beroptic pulmonary artery (PA) catheter
with the capability to continuously monitor mixed venous oxygen
saturation (SvO
2
). Initial maternal assessment fi ndings and ven-
tilator settings obtained and documented upon admission to the
tertiary care center are presented in Table 3.6 . Initial assessment
Table 3.5 Demographics and delivery characteristics of 51 obstetric patients
requiring mechanical ventilation.
Characteristic Value
Age (years) *
28.2 ± 7.4
Gravidity (number) *
3.0 ± 2.1
Parity (number) *
1.3 ± 1.9
Race (%)
White 56
Black 38
Asian, other 6
Estimated gestational age on admission (weeks) *
31.6 ± 5.1
Length of stay (days) *
10.9 ± 3.6
Days on ventilator *
3.4 ± 3.6
Pulmonary artery catheter used (number) 33 (65%)
Undelivered on admission (number) 43
Delivered during admission (number) 37 (86%)
Vaginal delivery (number) 13 (35%)
Cesarean delivery (number) 24 (65%)
Labor during ventilation (number) 11 (30%)
EGA at delivery (weeks) *
32.6 ± 4.9
Birth weight (g) *
2131 ± 1906
Neonatal intensive care nursery admission (number) 28 (76%)
Fetal/neonatal death (number) 4 (11%)
Maternal deaths (number) 7 (14%)
* Data are given as mean ± standard deviation.
Chapter 3
26
Table 3.6 Case example. Initial maternal assessment fi ndings and ventilator settings upon admission to the CCOB service.
Maternal assessment fi ndings

Vital signs

Blood pressure 100/52
Heart rate 132
Respiratory rate
Set 14
Total 36
S
a
O
2
100%

Arterial blood gases

pH 7.52
P
a
O
2
92 mmHg
P
a
CO
2
18 mmHg
Base excess +3.8

Hemodynamic values

CVP 4 mmHg
PAP 16/4 mmHg
PCWP 3 mmHg
CO 4.2 L/min
CI 2.3 L/min/m
2

SVR 1219 dyne/s/cm
5

PVR 95 dyne/s/cm
5

LVSWI 34 gM/m
2

Maternal assessment fi ndings

Oxygen transport values

C
a
O
2
12 mL/dL
CvO
2
7 mL/dL
DO
2
504 mL/min
V O
2
210 mL/min
O
2
ER 42%
Ventilator settings upon arrival
Mode Assist control
Tidal volume (Vt) 600 mL
Rate (set) 14
F
i
O
2
0.60
PEEP 5 cmH
2
O
PSV 5 cmH
2
O
CVP, central venous pressure; PAP, pulmonary artery pressure; PCWP, pulmonary capillary wedge pressure; CO, cardiac output; CI, cardiac index; SVR, systemic vascular
resistance; PVR, pulmonary vascular resistance; LVSWI, left ventricular stroke work index.
C
a
O
2
, arterial oxygen content; CvO
2
, venous oxygen content; DO
2
, oxygen delivery; VO
2
, oxygen consumption; O
2
ER, oxygen extraction ratio.
F
i
O
2
, fraction of inspired oxygen; PEEP, positive end - expiratory pressure; PSV, pressure support ventilation.
Figure 3.7 Case example. Initial fetal heart rate and uterine activity upon admission to the CCOB service.
Critical Care Obstetric Nursing
27
transport to tissues. Interpretation of FHR data included the
presence of a baseline fetal tachycardia, a relatively smooth FHR
baseline via external or indirect monitoring, absence of FHR
accelerations, and the presence of repetitive late decelerations of
the FHR. Regular uterine contractions were evident on the EFM
tracing. Manual palpation by the nurse revealed the contractions
to be mild to moderate in intensity and the uterine resting tone
was also noted to be inadequate.
Nursing diagnoses, based upon interpretation of assessment
fi ndings, included decreased cardiac output, impaired gas
exchange, ineffective breathing pattern, impaired maternal and
fetal oxygen transport, and anxiety [25] . Desired outcomes
included optimization of cardiac output, maternal and fetal oxygen
transport and gas exchange, as well as establishment of an effective
breathing pattern and reduction in the level of patient anxiety.
In order to develop a plan of care, the CCOB physician was
contacted and the assessment fi ndings and nursing diagnoses were
discussed. Collaboration resulted in a plan of care intended to
achieve the desired outcomes. Interventions to optimize cardiac
output began with correction of the patient ’ s low preload. As
demonstrated by the Starling curve, within certain physiologic
limits, the higher the fi lling pressure in the ventricles during dias-
tole, the greater the quantity of blood that will be ejected during
systole. In addition, increased fi lling pressures may improve ven-
tricular contractility, also known as the inotropic state of the heart,
thus further increasing cardiac output. Rapid intravenous admin-
istration of crystalloid fl uid was initiated in order to increase left
preload and improve left ventricular contractility. This process is
both delicate and dynamic. The goal is to determine and maintain
the optimal pulmonary capillary wedge pressure (PCWP) that, in
turn, optimizes left ventricular contractility and cardiac output.
Frequent assessment by the nurse of critical data is imperative,
since an excessively high PCWP may further diminish the function
of the left ventricle, decrease cardiac output, and lead to congestive
failure and pulmonary edema. In addition to administration of
intravenous fl uid, the nurse repositioned the patient to optimize
preload and displaced the uterus laterally to facilitate venous
return to the heart. In order to further facilitate oxygen transport,
the CCOB physician ordered administration of 2 units of packed
red blood cells (PRBCs). Since 98 – 99% of oxygen is chemically
bound to hemoglobin, in contrast to the 1 – 2% of oxygen which is
dissolved under pressure in the plasma, though the patient was not
anemic, it was thought that even a modest increase in hemoglobin
would signifi cantly improve arterial oxygen content and, thus,
oxygen delivery.
Interventions to optimize maternal – fetal gas exchange and
oxygen transport also included changes in mechanical ventilator
settings. The mode of mechanical ventilation was changed to
synchronized intermittent mandatory ventilation (SIMV). This
was based on the rationale that, when the mode of assist control is
utilized, the “ triggering ” of breaths above the set number of
breaths to be delivered by the machine may result in excessive
elimination of carbon dioxide. Since a compensated respiratory
alkalemia exists during normal pregnancy, further reduction
in levels of carbon dioxide increase the risk of development of
respiratory alkalemia. Assessment fi ndings that supported this
concept included the arterial blood gas results. The arterial oxygen
saturation of 100% could be the result of a left shift of the oxyhe-
moglobin dissociation curve. In addition, tachypnea signifi cantly
increased the total number of breaths delivered by the machine at
the preset tidal volume. Initiation of SIMV allowed both spontane-
ous patient breaths at her own tidal volume, and a set number of
mechanical cycles timed to coincide with spontaneous effort. The
level of positive end - expiratory pressure (PEEP) was increased in
order to recruit additional alveoli for participation in gas exchange.
In addition, the level of pressure support was increased in order
to decrease the patient ’ s workload during spontaneous breaths.
The fraction of inspired oxygen (F
i
O
2
) was decreased to 0.40.
A number of interventions were initiated to reduce patient
anxiety. First, an open policy of visitation, which allows visiting
24 hours a day, commensurate with the standard visitation policy
within the labor and delivery unit, was initiated. This facilitated
involvement of the patient ’ s husband and other family members
in the overall plan of care. Opportunities for more frequent dis-
cussions between the family and members of the healthcare team
facilitated a better understanding of prescribed interventions,
goals of therapy, and patient progress. In addition, the family had
more opportunities to ask questions and express concerns. A
method was identifi ed which allowed the patient to communicate
with the CCOB nurse, family members, and other members of
the healthcare team. An arterial catheter was utilized for repetitive
collection of blood for arterial blood gas assessment. The endo-
tracheal tube was secured and care was taken to minimize move-
ment of the tube which has been well documented as a source of
discomfort, irritation and anxiety in patients receiving mechani-
cal ventilatory support. A closed, or “ in line ” , system was utilized
for endotracheal suctioning. This system eliminates the need to
disconnect ventilator tubing from the endotracheal tube when
suctioning is indicated. Finally, every attempt was made to mini-
mize extraneous stimulation such as bright lights, alarms, and
general noise originating from outside the patient ’ s room.
A consultation with a neonatologist was obtained who pro-
vided multiple opportunities for the patient and family to verbal-
ize questions. Equipment, supplies and other resources were
made available in the patient ’ s room, in the event delivery
occurred and immediate neonatal care was needed.
Evaluation of the patient ’ s response to these interventions
ensued. Subsequent maternal assessment fi ndings are presented
in Table 3.7 . Interpretation of these data indicates signifi cant
improvement in cardiac output, optimization of preload, and
improved left ventricular contractility. In addition, oxygen deliv-
ery increased signifi cantly, as did arterial oxygen content. Oxygen
consumption increased indicative of improved oxygen delivery
and oxygen extraction capability. Arterial blood gases indicated
a compensated respiratory alkalemia, the normal acid – base state
expected during pregnancy. Resolution of the patient ’ s tachypnea
also occurred and her work of breathing was decreased. Sub-
sequent fetal assessment fi ndings are presented in Figure 3.8 .
Chapter 3
28
Figure 3.8 Case example. Subsequent fetal heart rate and uterine activity following interventions.
Table 3.7 Case example. Maternal assessment fi ndings and ventilator settings following interventions.
Maternal assessment fi ndings

Vital signs

Blood pressure 97/50
Heart rate 96
Respiratory rate
Set 12
Total 21
S
a
O
2
97%

Arterial blood gases

pH 7.41
P
a
CO
2
30 mmHg
P
a
O
2
164 mmHg
Base excess +2.6

Hemodynamic values

CVP 4 mmHg
PAP 28/14 mmHg
PCWP 12 mmHg
CO 10.2 L/min
CI 5.6 L/min/m
2

SVR 486 dyne/s/cm
5

PVR 56 dyne/s/cm
5

LVSWI 95 gM/m
2

Maternal assessment fi ndings

Oxygen transport variables

C
a
O
2
16 mL/dL
CvO
2
12 mL/dL
DO
2
1632 mL/min
V O
2
408 mL/min
O
2
ER 25%

Ventilator settings

Mode SIMV
Tidal volume (Vt) 600 mL
Rate (Set) 12
F
i
O
2
0.40
PEEP 8 cmH
2
O
PSV 10 cmH
2
O
CVP, central venous pressure; PAP, pulmonary artery pressure; PCWP, pulmonary capillary wedge pressure; CO, cardiac output; CI, cardiac index; SVR, systemic vascular
resistance; PVR, pulmonary vascular resistance; LVSWI, left ventricular stroke work index.
C
a
O
2
, arterial oxygen content; C
v
O
2
, venous oxygen content; DO
2
, oxygen delivery; VO
2
, oxygen consumption; O
2
ER, oxygen extraction ratio.
F
i
O
2
, fraction of inspired oxygen; PEEP, positive end - expiratory pressure; PSV, pressure support ventilation.

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