Effects of Smoking on Organ Systems
Respiratory
- β mucus, β mucociliary clearance, hyper-reactive airways
- β FRC, β closing capacity β atelectasis; V/Q mismatch & shunt; β pulmonary immunity
Cardiovascular
- Nicotine β β sympathetic tone, HR, BP, contractility, myocardial work
- CO β β Oβ delivery; 3Γ cardiovascular death risk; impaired supplyβdemand
Haemostatic & other
- β Hct, thrombocytosis, β platelet reactivity β thromboembolism, atherosclerosis
- GORD; impaired wound healing; β PONV but higher pain scores & opioid need
The two phases of smoke
- Particulate: nicotine (nicotinic ACh agonist, sympathetic, CYP450 induction), 70 carcinogens
- Gaseous: carbon monoxide β 250Γ Oβ affinity, left-shifts ODC; COHb ~15% in smokers vs ~1% non-smokers
CYP450 induction (maximal within ~24 h of smoking) increases dose requirements for CYP1A2/3A4 substrates β notably rocuronium/vecuronium (up to ~25% more), fentanyl/sufentanil, theophylline and ropivacaine.
Smoking Cessation β the Timeline
| Time smoke-free | Benefit |
|---|---|
| 12β24 h | CO & nicotine levels fall |
| 48β72 h | COHb normalises, ciliary function improves |
| 1β2 weeks | β sputum production |
| 4β6 weeks | PFTs improve |
| 6β8 weeks | Immune function & metabolism normalise |
| 8β12 weeks | β overall post-op morbidity & mortality |
Vaping / ENDS: e-cigarettes deliver nicotine Β± THC, carcinogens, endotoxins and flavourings (e.g. diacetyl β bronchiolitis-obliterans-like injury). Peri-operative evidence is limited; treat as an airway irritant with cardiovascular (nicotine) effects β and be aware of EVALI (e-cigarette/vaping-associated lung injury), a diagnosis of exclusion.
Pre-operative Optimisation
π Optimisation checklist
- Assess degree of impairment & functional capacity; identify & correct modifiable risk factors
- Treat any respiratory infection / worsening cough / dyspnoea; delay elective surgery through an exacerbation
- Smoking cessation (ideally β₯ 6β8 weeks); correct anaemia, nutrition & hydration
- Optimise bronchodilator therapy; pulmonary rehabilitation, chest physiotherapy, incentive spirometry, mucolytics & systemic hydration
- Risk-stratify for post-op pulmonary complications (PPCs)
Drug therapy (maintenance)
- LAMA + LABA dual bronchodilators are the backbone
- Anticholinergics first-line (ipratropium, tiotropium) β block vagally-mediated bronchoconstriction, a key COPD component
- Ξ²β-agonists β synergistic; inhaled corticosteroids (esp. if eosinophilic); oral steroids for exacerbations
Methylxanthines β caution
- Theophylline enhances diaphragmatic contraction but has a narrow therapeutic index
- Risk of tachyarrhythmias, seizures, rhabdomyolysis; volatile agents sensitise the myocardium to its toxicity