M & MDr Nicholas Martin

SCGH31/10/13

Batphone rings: ETA 5 min• 53yo• Collapse at work• Increased WOB• GCS 10/15• “silent chest”• IHD & Asthma/COPD Hx• RR40 Hr 135 BP 190/- SaO2 99% RA• Given ventolin / IM adrenaline

How do you prepare?

On arrival 12:43• Red faced, sweaty• Positioned upright NRBM• GCS 10/15 E4 (scared looking), V1, M4• Increased WOB++• RR 44• HR 130• SBP 220• SaO2 92% on NRBM• Silent chest on auscultation

What are your initial actions?

Initial actions• IV and bloods (VBG urgently)• Neb Salbutamol continuous• IV hydrocortisone 200mg• BiPAP applied 12:45 12/5 100% O2

Further Hx from SJA• More breathless than usual this am at home • Wheezy at work with progressive worsening SOB• Near collapse with reduced GCS• PMHx

• Brittle COPD/asthma (no home O2) though limitations to normal activity • IHD stent x2 on antianginals (ISMN)

1st VBG backpH 7.24 pCO2 144 HCO3 32 K5.4 Na 142 Ca 1.12• Interpret this result.• Acutely for every rise of CO2 by 10 expect a rise of HCO3 by 1

• Therefore expected HCO3 = 24 + 10 = 34

• Current obs • Temp 37.1 Hr 116 RR 30 BP 172/102 SaO2 96% ongoing WOB +++ very poor

air entry

What actions would you take now?

HCO3(Baseline 24 mmol/L)

Every 10 mmHg change in PaCO2from baseline 40

mmHg

ACUTE CHRONIC

↑PaCO2 1 4↓PaCO2 2 5

Over 10 minutes, no obvious change clinicallyManagment• Continue with BiPAP• Continuous salbutamol nebs (faff related to setting up neb with BiPAP)• Preparing IV Salbutamol (faff)• IV Saline 1L hung, running 125ml/hr• Prepare for intubation – drugs / staff / equipment / monitoring• Informed ICU

What else could have been done?

What else could have been done?

• Anticholinergic therapy Ipratropium 500 mcg

• Magnesium Magnesium 2g IV infusion over 20 or nebulized

• Adrenaline – if in extremis, give up to 5 µg/kg slowly IV as 1:10 000 or 1:100 000 dilution. Or give 0.3 – 0.5 mg IM for asthma in anaphylaxis.

Over 10 minutesInvestigations • ECG sinus tachy, no ischaemic changes• CXR…

When do you intubate an asthmatic?• Never… unless you absolutely have to.

• Can be life saving though high risk and complications

Absolute indications• cardiac or respiratory arrest• severe hypoxia (e.g. hypoxic seizure)• rapidly deteriorating level of consciousness

Relative indications• progressive patient fatigue• hypercapnea

Repeat VBG• pH 7.18 PCO2 199• HR 113 RR 26 BP 170/90 SaO2 97%

Pt Intubated

What induction drugs would you use?

Intubation• Best operator (FACEM)• Ketamine 200mg (2mg/kg)• Suxamethonium 150mg (1.5mg/kg)• Grade I view • Placement Sz 8 ETT confirmed with gold standard• EtCO2

Immediately post intubation• Pt manually BVM ventilated• Vecuronium 10mg given• Hr 110 BP 160 SaO2 100%• Everybody fist pumping / chest bumping / high 5’s all’round• Within a few minutes of intubation…

Rapid progression to bradycardia then PEA arrest

CPR started and adrenaline 1mg given.What just happened?• Tension Pneumothorax• Tamponade• Thrombosis / embolism• Toxin

•Hypovolaemia•Hyper/Hypothermia•Hyperkalaemia /

electrolyte / H+•Hypoxia

Important causes in asthma to consider• ‘Stacking’ or dynamic hyperinflation (gas-trapping) due to excessive

ventilation — especially in the patient with bronchospasm.

• Hypovolemia exacerbated by decreased venous return due to positive intrathoracic pressure.

• Vasodilation and myocardial depression due to the induction drugs used for rapid sequence intubation (e.g. thiopentone, propofol).

• Tension pneumothorax due to positive-pressure ventilation.

Breath Stacking: what do we do?

• Disconnect from maching / BVM• Allow complete expiration (may take 30seconds)

• In this case no audible expiration beyond a few seconds• Ventilated during arrest at 10 breaths / minute

Tension pneumothorax• Already barrel chested• Already quiet / silent chest• How are we going to know?• What if we aren’t sure?

My feeling is Asthma arrest… STAB ITHowever we did have US available at hand. In seconds demonstrated no movment L side

Bilateral Needle thoracostomy• I need a model torso…

Bilateral ICC following needle thoracostomy

• ICC left persistent air leak

• ICC Right decompressive hiss

Other considerationsFluid load – no published ‘evidence’, but necessary particularly prior to intubation when acute drop in preload is likely. Given 2L N/Saline stat

Hyperkalaemia? K+ 5.4 then used Sux: Given HCO3 100mmol and CaCl 10ml 10%. Intra arrest K+ post this 3.6

Cardiac event? Known IHD on ISMN possible cardiac event secondary to acidaemia and hypoxaemia.

OUTCOME• ROSC after 15 minutes CPR and above interventions in addition to standard

• Initially cardiovascular instability requiring high dose inotropes though settled in ICU.• No ischaemic ECG changes post ROSC

• Trial therapeutic hypothermia in ICU

• Devastating hypoxic brain injury, care withdrawn and organ donation

Areas for improvement…• More aggressive initial medical management

• IV fluid loading pre intubation

• Post intubation ventilation strategy

• Selection / availability of needles for needle thoracostomy

Ventilation strategy for asthmatics“permissive hypercapnoea”, avoid DHI / barotrauma

• Tidal volume 6-8 mL/kg• Slow respiratory rate (e.g 8-10/min)• High inspiratory flow rate (e.g 80-100L/min) to allow longer expiratory

times• I:E ratio 1:4 • FiO2 titrated to keep SaO2 >93%.