With respect to pregnancy.
a. Indicate how the following variables change in the third trimester (either increase or decrease or no change).
Variable |
Direction of Change |
Systolic Blood Pressure |
|
Diastolic Blood Pressure |
|
Heart Rate |
|
Blood Volume |
|
Haematocrit |
|
Tidal Volume |
|
pH |
|
PCO2 |
|
PO2 |
|
Bicarbonate |
b. List 4 conditions specific to pregnancy which may result in right or left heart failure or both.
c. Outline the major differences in approach to cardiopulmonary resuscitation in pregnancy as compared to the non-pregnant adult.
a. Indicate how the following variables change in the third trimester (either increase or decrease or no change).
Variable |
Direction of Change |
Systolic Blood Pressure |
Decrease |
Diastolic Blood Pressure |
Decrease |
Heart Rate |
Increase |
Blood Volume |
Increase |
Haematocrit |
Mild decrease |
Tidal Volume |
Increase |
pH |
No change |
PCO2 |
Decrease |
PO2 |
Increase |
Bicarbonate |
Decrease |
b. List 4 conditions specific to pregnancy which may result in right or left heart failure or both.
• Peripartum cardiomyopathy
• Amniotic fluid embolism
• Pre-eclampsia
• Tocolytic pulmonary oedema
• Pulmonary thromboembolism
c. Outline the major differences in approach to cardiopulmonary resuscitation in pregnancy as compared to the non-pregnant adult.
• CPR in left lateral position (27 degree tilt)
• Consideration for emergency caesarian section
• Hands slightly higher on sternum for chest compressions
• Additional personnel / equipment for emergency c-section and neonatal resuscitation
This entire question draws heavily from Oh's Intensive Care manual: Chapter 64 (pp. 684) General obstetric emergencies by Winnie TP Wan and Tony Gin,
Question a) specifically refers to Table 64.1 on page 685. A summary of the normal physiological changes in pregnancy can be found elsewhere.
In summary:
a)
Question a) specifically refers to Table 64.1 on page 685. A summary of the normal physiological changes in pregnancy can be found elsewhere.
b) is perfect as a list. Amniotic fluid embolism actually causes right heart failure at first, and then turns into LV failure. In fact, it would be even more perfect as a table:
This works best as a table. In fact, in Sliwa et al (2010) there is an even better table (Table 3. p.772)
Left-dominant | Right-dominant |
|
|
Potentially bi-ventricular:
|
c) is well discussed in the chapter on cardiac arrest in the pregnant patient. In short:
Keep in mind the following alternative causes of arrest:
Issues which complicate the pregnant arrest and peri-arrest scenario:
Manually displace the uterus to the left (off the aorta and vena cava)
b) is perfect as a list. Amniotic fluid embolism actually causes right heart failure at first, and then turns into LV failure
To (c) I might add that the emergency caesarian should be considered after 4 minutes of CPR, as per the ILCOR guidelines. The weirdly specific 27° pelvis tilt mentioned by the college can get you reaching for a protractor. It probably comes from the old AHA guidelines (these days the guideline-makers for the ECC and AHA no longer recommend the left lateral tilt (see the 2015 AHA update and the 2015 ECC guidelines).A left lateral tilt may compromise effective CPR, but is still recommended by the ARC Guideline 11.10 (2011) "Special Circumstances". Presumably, once the ARC get around to it, their guidelines will fall in line with international consensus. The 27° figure comes from Rees and Willis (1998), who got physicians to perform CPR on specially modified mannequins at different degrees of tilt. The authors found that the 27 degrees was the angle at which safe positioning and compression efficacy were at optimal compromise. Chest compression force was not too badly affected (80% of the force of compressions with the patient in a supine position), and the patient was unlikely to roll off the bed at this angle.
Oh's Intensive Care manual: Chapter 64 (pp. 684) General obstetric emergencies by Winnie TP Wan and Tony Gin
ARC Guideline 11.10 (2011) "Special Circumstances".
Rees, G. A. D., and B. A. Willis. "Resuscitation in late pregnancy."Anaesthesia 43.5 (1988): 347-349.