Loss of Resistance to Air (LORA)
This technique is briefly described here because many consultants still use it. It is however generally considered slightly less effective and less safe.
This technique uses air in the loss of resistance syringe instead of saline. Air is compressible so the technique has a different feel. The loss of resistance may be less sudden.
The major advantage of LORA is that there is no confusion when fluid drips back from your needle.
There are some reported disadvantages that include:
- Incomplete analgesia
- Pneumocephalus, headache and cranial nerve palsies
- Spinal cord or nerve root compression
- Venous air embolus (not significant in adults)
In general, stick with saline.
References
Laviola S, Kirvela M, Spoto MR, Tschuor S, Alon E. Pneumocephalus with intense headache and unilateral pupillary dilatation after accidental dural puncture during epidural anesthesia for cesarean section. Anesth Analg 1999; 88: 582–3.
Yentis SM. Time to abandon loss of resistance to air. Anaesthesia 1997; 52: 184.
Gonzalez-Carasco FJ, Aquilar JL, Llubia C, Nogues S, Vidal-Lopez F. Pneumocephalus after accidental dural puncture during epidural anesthesia. Reg Anesth 1993; 18: 193–5.
Aida S. Taga K, Yamakura T, Endoh H, Shimoji K. Headache after attempted epidural block: the role of intrathecal air. Anesthesiology 1998; 88: 76–81.
Krzysztof M. Kuczkowski, MD and Jonathan L. Benumof, MD Images in Anesthesia: Headache caused by pneumocephalus following inadvertent dural puncture during epidural space identification: is it time to abandon the loss of resistance to air technique? Canadian Journal of Anesthesia 50:159-160 (2003)
Dalens B, Bazin JE, Haberer JP. Epidural bubbles as a cause of incomplete analgesia during epidural anesthesia. Anesth Analg 1987; 66: 679–83.
Saberski LR, Kondamuri S, Osinubi OY Identification of the epidural space: is loss of resistance to air a safe technique? A review of the complications related to the use of air. Reg Anesth. 1997 Jan-Feb;22(1):3-15.