The young, the old and the very pregnant Flashcards
What are the Cardiovasc & haem changes of pragnancy?
- Hypoalbuminaemia, anaemia (relative)
- Hypercoagulable state
- Dec systemic vascular resistance (progesterone)
What respiratory physio changes during pregnancy ?
- ↑ Sensitivity of respiratory centres to CO2
- ↑ Metabolic O2 demand
- ↑ Intra-abdominal pressure
What does this mean for us as anaesthetisis?
Pregnant animals are:
- Less tolerant of apnoea
- Risk of hypoxia -> pre-oxygenate!
What Gi changes during pregnancy?
- ↓ Gastric emptying
- ↓ Lower oesophageal sphincter tone
- Cranial displacement of stomach
What can we do to remediate this ?
→ RegurgitaƟon & aspiraƟon pneumonia
→ SucƟon ready, rapid sequence intubaƟon
→ Antiemetic & gastro-protectant drugs
What neuro changes of pregnancy? What does this mean?
- CNS depression (progesterone)
- ↑ Blood Brain Barrier (BBB) permeability
Means:
→ ↓ Drug dose requirements, titrate to effect
→ Calculate dose according to physiological body weight
What anaesthetics considerations of C-section (in emergency)?
Mother & puppies anaesthetised together: placental drug transfer (diffusion)
GOALS:
* AVOID FOETAL HYPOXIA! → Risk of neonatal mortality
* Maintain cardiac output, normotension → maintain uterus blood flow
* Pain & stress → vasoconstricƟon → reducing placental blood flow* Maternal respiratory depression
What should WE do as anaesthetists of emergency C-section?
- Evaluate maternal cardiovascular status & foetal viability
- Check PCV/TS, glucose, electrolytes (Ca2+ & Mg2+)
- IV access (usually without premedication)
- Stabilise (IVFT, electrolytes…)
- Pre-oxygenation
- Minimise anaesthetic & surgical times
Should you pre-med C section?
- Often no but some pros and cons
- Short acting /drugs that can be antagonised
- Lower drug dosages
What pros & cons fo pre-med in emergency C-section?
What drugs should you NOT use for emergency C-section?
Acepromazine & Benzodiazepines & Ketamine
What drugs should you be CAREFUL about using in C-sec?
- Opioids
- Alpha 2?
Propofol & alfax use for induction for C-section?
Both okay although Alfax potentially better neonatal survival
What intra-op analgesia for C section?
- Epidural with Lidocaine/Ropivacaine/Bupivacaine before surgery: ↓ dose
- Line block/splash block/intraperitoneal lavage/ TAP block….
What analgesia AFTER puppies delivered?
- Methadone or buprenorphine IV/IM
- NSAIDS (e.g. Carprofen) SC
- Transfer to milk…but low amounts?
Detail Neonatal care?
- Clear fluid from oropharynx → sucƟon device
- Clamp umbilical vessels
- Gentle rubbing to stimulate breathing (+ dry & warm up)
- O2 / intubation/ventilation if required
- Acupoint VG 26 on philtrum
- Reversal drugs (naloxone…)
- Check for birth defects
- Careful introduction to the mother
- Consider dextrose supplementation
- APGAR SCORES
What is the neonatal vs paediatric vs juvenile periods?
What neuro physiology in paediatric patients? Waht does that mean for us?
- Parasympathetic Nervous System dominance
- Response to stress: bradycardia
- ↑ Blood brain barrier permeability
Means
DECREASE drug doses
Pain treatment physiology in paediatrics?
- Ascending nociceptive pathways fully functional
- CNS plasƟcity → pain causes changes in pain pathways
→ permanent damage & chronic pain
-> Treat pain at all ages
What cardiovascular physiological considerations in paediatric patients
Haem considerations in paediatric patients?
- Small blood volume
- Lower Hb & PCV
- Immature coagulation system
-> haemorrhage risk
Respiratory considerations of Paediatric patients ?
- ↑ O2
consumption (high metabolic rate) - Less response to change in 02 & CO2
- ↑ Minute volume
- Risk ventilatory fatigue
What can WE do about this?
Pre-oxygenate!
Hepatic considerations in paediatric patients?
- Reduced hepatic function
- ↓ drug metabolism → longer duraƟon of acƟon
- > free drugs in circulations (low albumins)
What should we do about hepatic considerations?
-> Reduces drug dosages
&
* HYPOGLYCAEMIA: do not fast (or minimal fasting)
→ Blood glucose monitoring +/- supplementation
→ Feed ASAP on recovery
Renal considerations of paediatrics?
- Low GFR
- Low ability to excrete excess water: risk fluid overload
- Slower drug elimination
→ Reduced drugs dosages required
Why are paediatric patients more prone to hypothermia?
- Large surface area: volume ratio
- Low fat reserves
- Limited ability to thermoregulate
How can we prevent hypothermia?
→ Prewarming & active warming
→ Minimise clipping & use of alcohol solutions
→ Minimise anaesthetic/surgical time
→ Low fresh gas flow
→ Warm intravenous fluid therapy
Additional Considerations
- Challenging IV catheter placement?
- Difficult intubation
- Risk of respiratory obstruction
- Risk endo-bronchial intubation
- Lack of adequate equipment/ ↑ dead space
- Weight accurately
- Limited licensed drugs available
Pre-Med for paediatrics?
- Opioids (pethidine, buprenorphine, methadone)
- +/- Benzodiazepines (midazolam)
Induction & maintenance in paediatric patient?
Induction: propofol, alfax
Maintenance: MAC sparing techniques / Iso
Analgesia & Fluids for paediatric patient?
Analgesia : opioids, local anaesthetics, NSAID
Fluid Therapy: Hartmanns + glucose
Neuro physiology in geriatric patients?
- ↓ Brain size, loss of neurons, neurotransmitters
- Poor hearing/blindness/cognitive dysfunction
- Poor thermoregulation
What should WE do about this?
→ Reduced drug dose requirement
→ Minimise stress & anxiety
Cardiovascular physiology of geriatric patients?
- Myocardial fibrosis
- Vascular & myocardial stiffness
- PNS dominance & ↓ baroreceptors sensiƟvity
- ↓ Cardiac output & contracƟlity
- Hypotension
What does this mean for us?
→ Prone to cardiovascular diseases & arrhythmias
→ Less ability to compensate to changes/stress
Respiratory considerations in geriatric patients?
- ↓ Lungs and chest compliance & elasƟcity
- ↓ Compensatory responses to O2 & CO2 changes
- ↓ Minute volume & efficient gas exchange
→ risk HYPOXAEMIA/HYPOXIA - Risk of regurgitation & aspiration pneumonia
Hepatic & renal physiology in geriatric patients?
- ↓ funcƟon & perfusion
- Renal & liver diseases
→ ↓ drug metabolism & clearance → ↓ drug dosages, Ɵtrate to effect, drug
antagonists - ↓ Metabolic rate → HYPOTHERMIA
→ Prolonged recovery - Decreased albumin, clotting factor production
MSK physiology in geriatric patients?
- ↓ Muscle mass → shivering less effecƟve
- Decreased BMR
- ↓ Total body water, > fat
- ↓ Join flexibility/ OA → pain! careful posiƟoning
PreMed in geriatric patient?
- Treat pain, ↓ stress & anxiety
- ↓drugs dosages
- Select short acting drugs/drugs with antagonist
- Careful with comorbidities
Induction in geriatric?
- Consider a co-induction with midazolam, fentanyl, lidocaine, ketamine…(especially if comorbidities)
- Always calculate dose first, give slowly to effect
Analgesia in geriatric?
- Opioids
- Loco regional anaesthesia
- Ketamine/fentanyl/Lidocaine (bolus +/- CRI)
- NSAIDs (careful if gastro-intestinal, kidney, liver disease, hypotension, dehydration,
corticosteroid administered)
Recovery in geriatric?
- Slower
- Risk of emergency delirium
- Post-anaesthetic cognitive dysfunction?
- Provide a calm & quiet environment
- TLC
- Careful positioning & handling: osteoarthritis
- Active rewarming (HYPOTHERMIA)
