Obstetrics Flashcards

Question

In obesity, how do you dose patients for a GA for: 1. IV induction agents? 2. Suxamethonium? 3. Non-depolarising NMBDs?

Answer 1

1. Lean body weight 2. Actual body weight 3. Ideal body weight

Answer 2

1. Avoid maternal hypoxaemia/hypercarbia/hypotension/hypothermia/hyperthermia 2. Preferred time for non-elective surgery - lowest risk of preterm delivery & major embryonic development complete 3. Corticosteroids for lung maturation Avoid NSAIDs after 32 weeks

Answer 3

Airway: —avoid nasal intubation —difficult airway ``` RS: —increased O2 consumption —increased MV —compensated resp alkalosis —decreased FRC (20%) ``` CVS: —CO increased by 50% by 3rd trimester - may reveal underlying cardiac disease Renal: —increased renal blood flow and GFR —lower Cr - caution in AKI GI: —LOS tone decreased —gastric emptying unaffected

Answer 4

``` Anaemia Infection DIC PPH Renal tubular necrosis/AKI Prolonged hospital stay Complications of transfusion ```

Answer 5

``` Smoking Previous abruption Multiparity Previous uterine surgery/previous LSCS Pre-eclampsia/HTN Age <25 or >35 Thrombophilia Trauma ```

Answer 6

Systemic activation of coagulation leading to consumption of clotting factors causing haemorrhage with thrombotic complications

Answer 7

``` Haemorrhage Intrauterine death Amniotic fluid embolism Sepsis Pre-eclampsia Retained products of conception Induced abortion Acute fatty liver of pregnancy ```

Answer 8

``` Hb >80 Plts >75 PT >1.5 ratio Fibrinogen >2 Ionised calcium >1mmol/L Temperature >36 ```

Answer 9

``` —Maternal: Previous VTE Thrombophilia Age >35 BMI >30 Parity >3 Smoking Inflammatory conditions - IBD, cancer ``` ``` —Obstetric: Multiple pregnancy Pre-eclampsia LSCS Prolonged labour Stillbirth Preterm birth PPH ``` ``` —Transient risk factors: Other surgery during pregnancy Hyperemesis IVF Bone fracture/immobility from illness ```

Answer 10

Coagulopathy/anticoagulation Uncorrected maternal hypovolaemia Local infection

Answer 11

``` 40micro bolus (10-50mcg) 2 minute lockout ``` 1:1 nursing with trained staff able to recognise apnoea Midwife/nurse must be present at all times Capnography/apnoea monitoring No infusions used Supplementary oxygen used to maintain SpO2 >94%

Answer 12

``` BP >140/90 New onset after 20 weeks gestation PLUS one of: -Proteinuria (1+ on dip of PCr >30mg) -Organ dysfunction (LFTs, headache, AKI, low plts) -Placental dysfunction (IUGR) ```

Answer 13

Control BP <135/85 - to avoid intracerebral haemorrhage and prevent seizures Aspirin until 36 weeks Deliver before 37 weeks (or if >37 weeks deliver within 48 hours); may need steroids if before 34 weeks Avoid ergometrine Restricted fluid intake (80ml/hr) Monitor for any symptoms of eclampsia and treat

Answer 14

``` Previous PET BMI >30 Primiparous T2DM IVF SLE Maternal age >40 Multiple gestation CKD ```

Answer 15

Development of heart failure within the last month of pregnancy up to 5 months following delivery Absence of other cause identified LV systolic impairment with EF <45%

Answer 16

``` Maternal age >30 Multiparity Multiple pregnancy Obesity Hypertensive disorders Cocaine use ```

Answer 17

Coronary vasoconstriction Ergometrine also pulmonary and systemic vasoconstriction

Answer 18

- Nutrient/waste exchange - Gas transfer - Immune (barrier, Ig) - Hormone synthesis

Answer 19

- Simple diffusion - Facilitated diffusion - Active transport - Pinocytosis

Answer 20

The movement of maternal OHDC to the Right, and the movement of the foetal OHDC to the Left in utero-placental circulation. Caused by CO2 shift changing pH in favour of above; OHDCurves move apart, favouring offload from mother and uptake by foetus

Answer 21

Increased affinity of deoxygenated Hb for CO2 Relevant as foetus gives up CO2, maternal Hb deoxygenated and better able to take it

Answer 22

Fick’s law of diffusion: - molecular weight - lipid solubility - ionisation - surface area - protein binding/free drug - thickness of membrane Also: Maternal blood flow Maternal-foetal concentration gradient

Answer 23

All of them Pethidine crosses freely and gets trapped as it is metabolised to a less soluble metabolite

Answer 24

All, but some more than others Bupivacaine less than lidocaine, as is more protein bound

Answer 25

All induction drugs No NMBDs (ionised/plasma cholinesterases) Benzos All volatile agents Mg (pre-eclampsia) - can make for a floppy baby

Answer 26

Abnormal placentation plus endothelial dysfunction —Inadequate trophoblastic invasion and spiral arteries —Poor placental perfusion —Endothelial dysfunction produces imbalance of pro- and anti-angiogenic factors —Activation of coagulation cascade with microthrombi and end organ damage Causes: fluid shift, vasoconstriction and decreased placental blood flow

Answer 27

``` Labetalol Methyldopa Nifedipine Hydralazine (IV) Alpha blockers Magnesium ```

Answer 28

``` Maternal factors: —Infection (chorioamionitis) —Pre-eclampsia —Placental abruption —Antepartum haemorrhage ``` ``` Foetal factors: —Cord prolapse —Congenital malformations —Congenital infection —Idiopathic ```

Answer 29

Tocolytic drugs: —atosiban (competitive oxytocin antagonist) —Beta adrenoceptor agonists (inhibit uterine contraction) —calcium channel blockers (decrease uterine contractility) —GTN —Inhalational anaesthesia