Anterior mediastinal mass

 

Summary:

·        Complex surgery

·        Risk of ABC collapse under anaesthesia

·        Needs pre-op investigation and planning

 

Origin:

Mediastinum

·      Lymph node

·      Thymus

·      Germ cell

Lung

·      Bronchogenic carcinoma

Neck

·      Thyroid

Elsewhere

·      Metastasis

 

Issues:

Mass effects

tl;dr:

·      CICO

·      CVS collapse

Airway:

·      -> Failed intubation -> CICO

·      -> Dynamic hyperinflation -> obstructive shock

SVC:

·      Airway oedema -> CICO

·      ↑ICP -> CNS ischaemia

·      Ineffective upper limb veins

Heart:

·      CVS collapse at induction

Pericardial effusion:

·      CVS collapse at induction

Pleural effusion:

·      Re-expansion hypoxaemia (? shunt ? APO)

Metastases

·      Lesion-dependent

·      Not sure about significance

Metabolic

·      Native: e.g. T4 -> thyrotoxicosis

·      Paraneoplastic: e.g. PTHrP -> hypercalcaemia

Medication

·      Lymphoma -> glucocorticoid

·      Cancer -> chemotherapy -> cardiotoxicity, lung toxicity

·      Thyroid -> carbimazole, PTU

Mood

·      Anxiety

·      Grief

 

Assessment:

History

·      Airway: dyspnoea, cough, stridor, wheeze

·      Heart: supine syncope, dyspnoea

·      SVC: dyspnoea, facial swelling

·      Position: which is best?

Examination

·      General: conscious state, colour, respiratory effort, body habitus

·      Airway: stridor

·      Heart: signs of tamponade

·      SVC: oedema, flushing, Pemberton’s

·      Position: assess supine / head up / lateral / prone

Investigation

Imaging:

·      CT chest (? size ? vessel compression ? tracheobronchial compression

·      CT pan-scan (? mets)

·      TTE (? effusion ? chamber compression)

·      Spirometry (? fixed insp and exp obstruction)

Blood tests:

·      BGHO

·      Baseline FBE / UEC / coag

·      Baseline ABG

Treatment

·      Shrink the mass (e.g. glucocorticoid, chemo, rad)

·      Drain effusions (N.B. too quick -> re-expansion APO)

·      Treat its effects (e.g. hormone antagonist)

·      Widen the airway (i.e. tracheal stent)

·      Optimise comorbidities

Risk stratification

·      Hx/Ex/Ix

·      CVS collapse risk: ∝ size of mass + supine symptoms

·      Airway disaster risk: ∝ narrowing (beware if >50%, esp >70%)

Planning

MDT:

·      Oncology

·      Cardiothoracics

·      ENT

·      Anaesthesia

Discussion:

·      Plan: proceed vs abandon vs alternatives

·      Anaesthesia: local vs sedation vs GA

·      Disasters: airway and circulation

 

Preparation:

Personnel

·      Anaesthesia nurse

·      Second anaesthetist (preferably cardiac)

·      Technicians ready to flip the patient

·      ± Thoracics with rigid bronchoscope

·      ± Cardiac scrubbed for sternotomy

·      ± Cardiac scrubbed for ECMO

Equipment

Airway and breathing:

·      Usual equipment

·      Video laryngoscope

·      Flexible bronchoscope

·      Rigid bronchoscope

·      Microlaryngoscopy ETTs

·      Cophenylcaine (relaxant-free)

Circulation:

·      Pumpset

·      Fluid warmer

Monitoring

·      Standard

·      A-line

·      IDC

Drugs

·      Propofol TCI

·      Remifentanil TCI (<0.05mcg/kg/min)

·      Metaraminol infusion

·      Rocuronium (just in case)

Access

·      Large PIVC in UL and LL

·      A-line in LL

·      CVC in LL

·      Consider ECMO: must be pre-induction if at all

Airway

·      Face mask

·      Guedel

·      Video laryngoscope

·      Cophenylcaine

·      Bougie

·      MLT 6.0

 

Induction:

Default

·      Head up a bit (offload A,B,C)

·      Spont vent TCI

·      Remifentanil 0.025mcg/kg/min

·      Metaraminol infusion titrated

·      Propofol Cpt: 1mcg/mL, ↑0.5mcg/mL q1min until 6mcg/mL

·      Laryngoscopy + topicalization + bougie + reinforced ETT

High risk

·      Airway: AFOI pre-induction (or rigid bronchoscopy post-induction)

·      Circulation: ECMO pre-induction

·      Don’t forget: local only if possible

Paediatric

·      Pre-med: midazolam 0.5mg/kg

·      Topicalise: amethocaine

·      IV access: pre-op if at all possible

·      Parent: present for beginning of induction

·      Position: consider left lateral

·      Drug: prefer TCI, otherwise sevo/nitrous

·      Paralysis: avoid

 

Intra-op disaster:

Airway

·      Left lateral

·      FiO2 1.0

·      CPAP

·      IPPV

·      Bougie + corkscrew

·      Rigid bronchoscope

Circulation

·      Left lateral or prone

·      Fluid

·      Pressor

·      Less anaesthetic

·      Sternotomy + lift the mass

 

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