MAC in 100% O2
Des 6.6 Sevo 2.0 Iso 1.1 Xe 71 N2O 105
B:G (speed of onset/offset)
Des 0.45 Sevo 0.7 Iso 1.4 Xe 0.12 N2O 0.47
O:G (potency)
Des 29 Sevo 80 Iso 98 Xe 1.9 N2O 1.4
Neuraxial blockade levels
LSCS: T4 cold, T6 pinprick, down to S3 MROP: T6 Labour: T10 (pain is T10-L1 1st stage, S2-4 2nd stage) Cervical cerclage: T10 EVAR: T10 TURP: T10
Elimination t1/2 (m)
Morphine 170
Fentanyl 190
Alfentanil 100
Remi 10
Clearance (ml/kg/min)
Morphine 16 Fentanyl 13 Alfentanil 6 Remi 40 Thio 3 Pethidine 10
Vd (L/kg)
Morphine 4 Fentanyl 4 Propofol 4 Pethidine 4 Tramadol 4 Alfentanil 0.6 Remi 0.3 Thio 2
Plasma protein binding (%)
Morphine 35 Fentanyl 83 Alfentanil 90 Remi 70 Propofol 98 Thio 85 Pethidine 40 Tramadol 20 Lidocaine 65 Bupivacaine 95
pKa
Aspirin 3.0 Midazolam, alfentanil 6.5 Remi 7.1 Thio, diamorphine 7.6 Lidocaine 7.9 Morphine 8.0 Bupivacaine, ropivacaine 8.1 Fentanyl 8.4 Pethidine 8.7 Propofol 11.0
Unionised fraction at pH 7.4 (%)
Morphine 23
Fentanyl 9
Alfentanil 89
Remi 68
Relative lipid solubility
Morphine 1 Fentanyl 600 Alfentanil 90 Remi 20 Pethidine 30 Diamorphine 200
Cobb angle
10 degrees minimum for diagnosis of scoliosis
Surgery when >45-50 degrees
>60 = significant respiratory compromise
COSHH max agent concs (ppm)
Halothane 10
N2O 100
Enflurane/isoflurane 50
BP (degrees C)
Des 23 Sevo 58.5 Iso 48.5 Xe -108 N2O -89
SVP at 20C (kPa)
Des 88
Sevo 21
Iso 33
Steroid equivalence (mg) Pred, hydrocort, methylpred, dex
Pred 5
Hydrocort 20
Methylpred 4
Dex 0.75
Oral opioid equivalence (ratios)
Morphine, oxycodone, tramadol, codeine
Buprenorphine and fentanyl patches
Morphine 1
Oxycodone 2
Tramadol 0.15
Codeine 0.1
Transdermal:
Buprenorphine 5mcg/h patch = 12mg Oramorph
Fentanyl 50mcg/h patch = 180mg Oramorph
Umbilical vessel SpO2
Vein 70%
Artery 45%
Incidence of inherited diseases
Down’s 1 in 1000 live births
CF 1 in 2500 live births (1 in 25 carrier allele)
MD 1 in 8000 prevalence
CHD 1% live births
HCM 1 in 500 prevalence (25% cases obstructive)
SCD 1 in 2000 live births
Bicuspid aortic valve 0.5-2.5%
Autism 1%
RA 1-2%
MH 1 in 5000-10,000 susceptible; 1 in 40,000-100,000 GAs
Prevalence of acquired diseases
Diabetes 9% (90% type 2)
Post tonsillectomy bleed 0.5-2%
Asthma 12% (>1400 deaths/y)
COPD 2% (diagnosed; much more undiagnosed)
IHD 4%
HTN 30%
Obesity 27%
AF 5.5% (50% perm, 25% persis, 15% paroxys)
PD 1% of >65s
OSA 5-10%
Dementia 1% (7% of >65s)
AS 3% >65s, aortic sclerosis 25% of >65s (9% progress to AS)
GBS 1-2 in 100,000 (3-5% mortality)
MG 1 in 1000
Phaeo 1 in 100,000
Latex allergy 4.3% (9.7% in healthcare workers)
Penicillin allergy 10% reporting rate (90% of which are not truly allergic)
Anaphylaxis 1/5000-1/20,000, 3:1 female preponderance
Alcohol misuse 9% men, 4% women
PONV 30%
Commonest cancers
Breast 15%
Lung 13%
Prostate 13%
Bowel 11%
% metabolised
Des 0.02 Sevo 5 Iso 0.2 Xe 0 N2O 0
Molecular weights
Des 168 Sevo 200 Iso 184 Xe 131 N2O 44
Oral bioavailability (%)
Morphine 30 Methadone 75 Tramadol 70 Pethidine 50 Codeine 50 (but only 10% metab to morphine)