Table 3.

Summary of clinical and anamnestic clues linked to 4H's and 4T's

Hypoxia (asphyxia)	Hypokalemia	Hyperkalemia	Hypothermia	Hypovolemia	Tension pneumothorax	Cardiac tamponade	Pulmonary embolism	Toxins
Airway obstruction (e.g., aspiration)	Prolonged diarrhea	Renal failure	Exposure to cold	Excessive blood loss	Subcutaneous emphysema	Distended jugular veins	Sudden onset dyspnea	History of drug/ toxin ingestion
Hanging	Diabetes insipidus	Diabetes mellitus	Trunk appearing cold on palpation	Clinical signs of anaphylaxis	Absence of vesicular breath sounds	Laceration/bruising of chest wall	Chest pain	Pupil abnormality
Drowning	Cushing's syndrome	Addison's disease	Decreased core temperature		Tracheal deviation		Cough	Needle marks
	Dialysis				Distended jugular veins		Hemoptysis	Oropharyngeal corrosion
							Clinical signs of DVT	Odors/smoke
							Prolonged period of inactivity
							Active cancer Former DVT

DVT, deep venous thrombosis.