CICM Second Part Exam Practice SAQs 20102022

Investigations

• PH defined as mean pulmonary artery pressure ³ 25mmHg
• Tests should focus on 
  • confirming diagnosis (echocardiography, RH catheterisation)
  • classifying type PH (bloods, RFT, echocardiography)
  • and grading severity (echocardiography, RH catheterisation)
• Bloods – BNP (?RHF), ANA/ENA (?CTD), ACE (?sarcoidosis), LFT (?PHTN), HIV serology
• ECG – ?RH strain or RVH (RAD, RBBB, dom R V₁, dom S V_5,6), ?large RA (p-pulmonale)
• Echocardiography – ?RH dysfunction, ?LH disease, ?valvular disease, ?PASP
• Respiratory Function Tests – ?COPD ?RLD ?normal spirometry low DLCO
• RH Catheterisation – confirm PH (mPASP > 25), ?PAH (PVR > 3 woods), ?RH Fx (CI)

Classification of Pulmonary Hypertension (PH)

1. Pulmonary Arterial Hypertension (PAH)
   1. Idiopathic
   1. Heritable
   1. Drug/toxin induced (e.g. amphetamines)
   1. Associated (CTD, HIV, portal HTN)
   1. Responders to CCB

• Left Heart Disease
  • HFrEF
  • HFpEF
  • Valvular disease

• Lung disease / chronic hypoxia
  • Obstructive lung disease
  • Restrictive lung disease
  • Hypoxia (obesity-hypoventilation) 

• Pulmonary artery obstructions
  • Chronic thromboembolic PH (CTEPH)
  • Other 

• Multifactorial aetiology
  • Hematological disorders (e.g. sickle cell) 
  • Systemic disorders (e.g. sarcoidosis)
  • Complex congenital heart disease
  • Other

REFERENCES:

JAMA. 2022;327(14):1379-1391. https://doi.org/10.1001/jama.2022.4402

MJA 2016; 205(6): 271-276. https://doi.org/10.5694/mja16.00468

Assessment

• History
  • Agent(s)
  • Dose(s)
  • Time since ingestion
  • Clinical features and progress
  • Patient factors (weight and co-morbidities)

• Investigations
  • [drug] – blood and urine
  • UEC – renal failure? hypoK+? hyperK+?
  • ABG – acidosis? hyperBSL? hypercapnia? hypoxia?
  • CK – rhabdomyolysis?
  • osmolar gap – toxic alcohol?
  • CXR – aspiration? NGT placement? 
  • ECG – rate, rhythm, PR, QRS, QTc, domR in AVR

Resuscitation 

• Always secure ABC first
• Consult early with toxicologist
• Seek and treat complications of overdose
  • Hyperthermia
  • Hypoglycaemia
  • Seizures 

Decontamination

Activated Charcoal

• within 1hr ingestion
• 50g (adult); 1g/kg (kids)
• indications
  • aspirin
  • paracetamol
  • digoxin
  • TCA
  • theophylline
  • phenobarbitone
  • paraquat

Multi-dose Activated Charcoal (MDAC)

• initial 50g bolus
• then 25g Q2H
• rarely useful > 6hrs
• indications
  • massive paracetamol OD
  • phenobarbitone coma
  • carbamazebine coma
  • theophylline OD

Enhanced Elimination

Urinary Alkalisation

• NaHCO3 iv 1-2mM/kg bolus
• then infusion 150mM over 4hrs
• frequent FWT; aim pH > 7.5
• regular K+ replacement
• monitor HCO3 and K+ Q4H
• continue until improving (clinical, lab)
• indicated drugs
  • salicylates
  • phenobarbitone

Haemodialysis (indications)

• toxic alcohols
• lithium (severe chronic)
• salicylate (severe)
• phenobarbitone (coma)
• carbamazepine (massive OD) 
• valproate (massive OD)
• theophylline OD
• metformin (lactic acidosis)
• paraquat (charcoal haemoperfusion)

Antidote Therapy

• Commence as early as possible
• In consultation with toxicologist
• May be empirically indicated during CPR 
• (e.g. NaHCO3, atropine, naloxone, digibind)

• Supposed benefit in the prevention of secondary neurological injury 
• There is no role for the use of hypothermia in the routine management of TBI
• Two landmark trials 
• EUROtherm3235
  • cooling in patients with sustained ICH in the setting of TBI
  • increased mortality in cooling group
  • and increased incidence of poor neurological outcomes
• POLAR 2018
  • therapeutic cooling of patients with severe TBI due to blunt trauma
  • no benefit in neurological outcomes or mortality
  • increased risk of infection and prolonged MV duration

REFERENCES:

Intensive Care Med. 2019; 45(12): 1783–1794. https://doi.org/10.1007%2Fs00134-019-05805-9

JAMA 2018 Dec 4;320(21):2211-2220. https://doi.org/10.1001/jama.2018.17075N Engl J Med 2015; 373:2403-2412 https://doi.org/10.1056/NEJMoa1507581