Investigations

• preferably using ultrasound guidance ^a
• otherwise a 20G needle and syringe ^a

Why?s

• 35% of diagnoses are made on history, examination, chest X-ray, macroscopic examination and first cytological study of pleural fluid. ^c
• Ultrasound guided thoracentesis reduces complications, particularly dry taps (inadequate tap, pain, subcutaneous haematoma or pneumothorax) ^a
• It is safer than using a 20G needle and syringe, or using a 14G as an introducer for a 16G needle, catheter and syringe.  ^a

Ultrasound-guided thoracentesis is safer using a needle and syringe

Patient	Treatment	Comparison	Outcome	CER	RRR (95% CI)	NNT (95% CI)
pleural effusion a	needle and catheter	needle	any complication   at 48 h	47%	-110% (-270% to -25%)	-2 -41 to -1)
	ultrasound-guided				66% (-9% to 90%)	3 (2 to 130)