Advantages of 1-1-12 Wash in Scheme during Induction with Low Flow Anesthesia with and without Nitrous Oxide

In the past, many wash-in schemes have been used with initially high fresh gas flow (FGF) to achieve the necessary alveolar concentration of inhalational agent in 10-15 min. This study was designed to show whether 1-1-12 wash-in scheme proposes an earlier achievement of induction or is there any requirement of high FGF phase to know the time taken for induction with and without nitrous oxide (N₂O).

The aim of the study was to find out the time required for the alveolar concentration of desflurane to be from 1% to 6% with and without N₂O.

It was a potential randomized study which was conducted on sixty patients admitted for elective surgery.

Two groups of thirty patients each were made and randomly assigned. Group N received desflurane with N₂O plus oxygen and Group A received desflurane with air plus oxygen.

The observations were noted and evaluated accordingly. Analysis was done using unpaired t-test.

Hemodynamic parameters were almost similar in both the groups. In Group N, gradual F_AD (Alveolar Desflurane concentration, i.e., end-tidal desflurane) from 1% to 6% was achieved at 0.5, 1, 1.5, 2, 3, and 4 min. In Group A, the same was achieved at 0.6, 1, 1.5, 2, 3, and 4 min (P > 0.05). No significant difference was found between the recuperation time and score in both the groups. Rather complications were more in Group N and statistically significant for nausea and vomiting.

Time taken to attain F_AD from 1% to 6% was 4 min in both the groups. It is concluded that the recitation of 1-1-12 wash-in scheme is autonomous on the use of N₂O and high FGF phase.