Critical Care Obstetrics part 4 doc

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 o

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 inserinduc-tion 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

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

Blood pressure 71/31 mmHg

Oxygen transport values

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 reducoptimiza-tion 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 µg/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

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

Blood pressure 127/75 mmHg

Oxygen transport values

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

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

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

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

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

Age (years) * 28.2 ± 7.4 Gravidity (number) * 3.0 ± 2.1 Parity (number) * 1.3 ± 1.9

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

Table 3.6 Case example Initial maternal assessment fi ndings and ventilator settings upon admission to the CCOB service

Maternal assessment fi ndings

Maternal assessment fi ndings Oxygen transport values

Tidal volume (Vt) 600 mL

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

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 documove-mented 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

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

Maternal assessment fi ndings Oxygen transport variables

Tidal volume (Vt) 600 mL

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