Page 56 - GSTL_7th May 2020_Vol 36_Part 1

14 GST LAW TIMES [ Vol. 36
disease or disorder. Nitrous Oxide is used as anesthetic agent. Medical oxygen
with 99.9% purity is predominantly used in hospitals. Medical Oxygen is also
used for the treatment of patients and to mitigate the intensity of disease or dis-
order in human beings. It is utilised to prevent a sudden collapse of patients and
to aid in the recovery of health. As stated in the Counter Affidavit filed by the
respondents, in order to carry out critical surgical procedures, supplemental ox-
ygen is administered to patients. Medical Oxygen is also administered in resusci-
tation, major trauma, anaphylaxis, major hemorrhage, shock and active convul-
sions, amongst other conditions.
30. Nitrous Oxide is used in surgery and dentistry for its anesthetic and
analgesic effects. An article published in the British Medical Bulletin titled ‘Past,
Present and Future of Nitrous Oxide’ [V Lew, E McKay, M Maze, Past, present,
and future of nitrous oxide, British Medical Bulletin, Volume 125, Issue 1, March
2018, Pages 103-119] highlights the medical use of Nitrous Oxide in the following
terms :
“As an anaesthetic gas, N 2O has many unique properties that have histori-
cally been used to great benefit in the operating room. These include a high
FA/FI ratio allowing for rapid onset and offset, anxiolytic as well as anal-
gesic and amnestic properties, lack of an odour and lack of irritation to the
tracheobronchial tree. These same properties have made it increasingly
popular in areas outside of the OR including paediatric procedural seda-
tion, the emergency room, obstetrics, and potentially psychiatry, for attenu-
ation of treatment-resistant depression.”
The World Health Organisation in its publication titled ‘Model Prescribing In-
formation : Drugs Used in Anesthesia’ [WHO Model Prescribing Information :
Drugs Used in Anaesthesia (1989)] states that Nitrous Oxide has the following
uses :
“Maintenance of surgical anaesthesia in combination with other anaesthetic
agents (halothane, ether, thiopental or ketamine) and muscle relaxants.
In sub-anaesthetic doses, to provide analgesia for obstetric practice, for
emergency management of injuries, during postoperative physiotherapy
and for refractory pain in terminal illness.”
K.D. Tripathi in Essentials of Medical Pharmacology [K.D. Tripathi, Essentials of
Medical Pharmacology, VIIth Ed., at p. 378] states :
“INHALATIONAL ANAESTHETICS 1. Nitrous oxide (N 2O). It is a colour-
less, odourless, heavier than air, non-inflammable gas supplied under pres-
sure in steel cylinders. It is non-irritating, but low potency anaesthetic; un-
consciousness cannot be produced in all individuals without concomitant
hypoxia; MAC is 105% implying that even pure N 2O cannot produce ade-
quate anaesthesia at 1 atmosphere pressure. Patients maintained on 70%
N 2O + 30% O 2 along with muscle relaxants often recall the events during
anaesthesia, but some lose awareness completely. Nitrous oxide is a good
analgesic; even 20% produces analgesia equivalent to that produced by
conventional doses of morphine.
…
3. Nitrous oxide. The patient is made to breathe 100% oxygen through a
nose piece or hood and N 2O is added in 10% increments (to a maximum of
50%, rarely 70%) till the desired level of sedation assessed by constant ver-
bal contact is obtained. This is maintained till the procedure is performed.
Thereafter, N 2O is switched off, but 100% O 2 is continued for next 5 min.
The patient is generally roadworthy in 30-60 min.”

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