Abstracts
The objective was to investigate the effect of nitrous/oxygen in chronic pain. Seventy-seven chronic pain patients referred to dental treatment with conscious sedation with nitrous oxide/oxygen had their records included in this research. Data were collected regarding the location and intensity of pain by the visual analogue scale before and after the treatment. Statistical analysis was performed comparing pre- and post-treatment findings. It was observed a remarkable decrease in the prevalence of pain in this sample (only 18 patients still had chronic pain, p < 0.001) and in its intensity (p < 0.001). Patients that needed fewer sessions received higher proportions of nitrous oxide/oxygen. Nitrous oxide may be a tool to be used in the treatment of chronic pain, and future prospective studies are necessary to understand the underlying mechanisms and the effect of nitrous oxide/oxygen in patients according to the pain diagnosis and other characteristics.
chronic pain; nitrous oxide; dental treatment; pain relief
O objetivo deste estudo foi investigar o efeito do óxido nitroso na dor crônica. Os prontuários de 77 pacientes com dor crônica submetidos a tratamento odontológico com sedação consciente (óxido nitroso/oxigênio) foram incluídos. Os dados sobre localização e intensidade de dor pela escala visual analógica foram considerados, e foi realizada comparação e análise estatística entre os momentos pré- e pós-tratamento. Foi observada redução marcante na prevalência de dor nesta amostra (apenas 18 doentes ainda tinham dor, p < 0,001) e na intensidade de dor (p < 0,001). Os doentes que precisaram de menor quantidade de sessões receberam maiores proporções de óxido nitroso/oxigênio. Em conclusão, pode-se considerar o oxido nitroso como uma ferramenta a ser investigada no tratamento da dor crônica em estudos futuros prospectivos, que poderão identificar os mecanismos associados de acordo com o diagnóstico de dor e outras características.
dor crônica; óxido nitroso; tratamento odontológico; alívio da dor
Conscious sedation with nitrous oxide is a well-known method used for more than 100 years
for dental treatment. Since 1976, it started to be used associated with oxygen and
became more secure11 .Szymańska J. Environmental health risk of chronic exposure to
nitrous oxide in dental practice. Ann Agric Environ Med.
2001;8(2):119-22.. It helps in the
control of anxiety and fear which play a role in acute pain perception, which wide
application at the dental practice22 .Brunick A, Clark M. Nitrous oxide and oxygen sedation: an update.
Dent Assist. 2010;79:22-3, 26, 28-30; quiz 32, 34.,33 .Daher A, Hanna RP, Costa LR, Leles CR. Practices and opinions on
nitrous oxide/oxygen sedation from dentists licensed to perform relative
analgesia in Brazil. BMC Oral Health. 2012;12(1):21.
http://dx.doi.org/10.1186/1472-6831-12-21
https://doi.org/10.1186/1472-6831-12-21...
.
Some of the observed effects of this type of sedation is the reduced need of analgesic
drugs in the postoperative period44 .Echevarría G, Elgueta F, Fierro C, Bugedo D, Faba G, Iñiguez-Cuadra
R et al. Nitrous oxide (N(2)O) reduces postoperative opioid-induced hyperalgesia
after remifentanil-propofol anaesthesia in humans. Br J Anaesth.
2011;107(6):959-65. http://dx.doi.org/10.1093/bja/aer323
https://doi.org/10.1093/bja/aer323...
,55 .Stiglitz DK, Amaratunge LN, Konstantatos AH, Lindholm DE.
Intraoperative nitrous oxide as a preventive analgesic. Anaesth Intensive Care.
2010;38(5):890-3.,66 .Soumpasis I, Kanakoudis F, Vretzakis G, Arnaoutoglou E, Stamatiou
G, Iatrou C. Deep anaesthesia reduces postoperative analgesic requirements after
major urological procedures. Eur J Anaesthesiol. 2010;27(9):801-6.
http://dx.doi.org/10.1097/EJA.0b013e328337cbf4
https://doi.org/10.1097/EJA.0b013e328337...
,77 .Yuxiang L, Lu T, Jianqiang Y, Xiuying D, Wanfang Z, Wannian Z et
al. Analgesia effect of a fixed nitrous oxide/oxygen mixture on burn dressing
pain: study protocol for a randomized controlled trial. Trials. 2012;13(1):67.
http://dx.doi.org/10.1186/1745-6215-13-67
https://doi.org/10.1186/1745-6215-13-67...
,88 .Duma A, Helsten D, Brown F, Bottros MM, Nagele P. The effect of
nitrous oxide anesthesia on early postoperative opioid consumption and pain. Reg
Anesth Pain Med. 2014;39(1):31-6.
http://dx.doi.org/10.1097/AAP.0000000000000039
https://doi.org/10.1097/AAP.000000000000...
,99 .Ko H, Kaye AD, Urman RD. Nitrous oxide and perioperative outcomes.
J Anesth. 2014;28(3):420-8.
http://dx.doi.org/10.1007/s00540-013-1729-y
https://doi.org/10.1007/s00540-013-1729-...
.
Initially, nitrous oxide was considered an anesthetic drug, however these findings
brought an evidence of an analgesic effect77 .Yuxiang L, Lu T, Jianqiang Y, Xiuying D, Wanfang Z, Wannian Z et
al. Analgesia effect of a fixed nitrous oxide/oxygen mixture on burn dressing
pain: study protocol for a randomized controlled trial. Trials. 2012;13(1):67.
http://dx.doi.org/10.1186/1745-6215-13-67
https://doi.org/10.1186/1745-6215-13-67...
,88 .Duma A, Helsten D, Brown F, Bottros MM, Nagele P. The effect of
nitrous oxide anesthesia on early postoperative opioid consumption and pain. Reg
Anesth Pain Med. 2014;39(1):31-6.
http://dx.doi.org/10.1097/AAP.0000000000000039
https://doi.org/10.1097/AAP.000000000000...
,99 .Ko H, Kaye AD, Urman RD. Nitrous oxide and perioperative outcomes.
J Anesth. 2014;28(3):420-8.
http://dx.doi.org/10.1007/s00540-013-1729-y
https://doi.org/10.1007/s00540-013-1729-...
.
This effect meant reduced doses of analgesic drugs after several types of surgeries88 .Duma A, Helsten D, Brown F, Bottros MM, Nagele P. The effect of
nitrous oxide anesthesia on early postoperative opioid consumption and pain. Reg
Anesth Pain Med. 2014;39(1):31-6.
http://dx.doi.org/10.1097/AAP.0000000000000039
https://doi.org/10.1097/AAP.000000000000...
, and it was considered a prevention for
acute and chronic postsurgical pains9,10,11.
The antalgic efficacy of nitrous oxide in acute pain models have been investigated since
that1212 .Del Valle Rubido C, Solano Calvo JA, Miguel AR, Delgado Espeja JJ,
González Hinojosa J, Zapico Goñi Á. Inhalatory analgesia with nitrous oxide vs.
other analgesic techniques in hysteroscopic polypectomy: pilot study. J Minim
Invasive Gynecol. Forthcoming 2015.,1313 .Yokoe C, Hanamoto H, Sugimura M, Morimoto Y, Kudo C, Niwa H. A
prospective, randomized controlled trial of conscious sedation using propofol
combined with inhaled nitrous oxide for dental treatment. J Oral Maxillofac
Surg. 2015;73(3):402-9.
http://dx.doi.org/10.1016/j.joms.2014.09.014
https://doi.org/10.1016/j.joms.2014.09.0...
,1414 .Manouchehrian N, Bakhshaei MH. Nitrous oxide effect on relieving
anxiety and pain in parturients under spinal anesthesia for caesarean section.
Anesth Pain Med. 2014;4(2):e16662.
http://dx.doi.org/10.5812/aapm.16662
https://doi.org/10.5812/aapm.16662...
,1515 .Sun WZ. Anesthetic or analgesic effect of N2O in acute
pain model? Reg Anesth Pain Med. 2014;39(3):263.
http://dx.doi.org/10.1097/AAP.0000000000000081
https://doi.org/10.1097/AAP.000000000000...
. On the other side, chronic pain is described as ‘pain for
more than 6 months’ by the International Association for the Study of Pain1616 .Merskey H, Bogduk N, editors. Classification of chronic pain:
descriptions of chronic pain syndromes and definitions of pain terms. 2nd ed.
Seattle: International Association for the Study of Pain; 1994.. Only recently, a review showed that
nitrous oxide can be a tool in the prevention of chronic pain development, but little is
known about its effect in preexistent chronic pain conditions1717 .Chaparro LE, Smith SA, Moore RA, Wiffen PJ, Gilron I.
Pharmacotherapy for the prevention of chronic pain after surgery in adults.
Cochrane Database Syst Rev. 2013;7:CD008307.
http://dx.doi.org/10.1002/14651858.CD008307.pub2
https://doi.org/10.1002/14651858.CD00830...
.
A study from 5 years ago showed persistent pain alleviation in a neuropathic pain model
by a single exposure to nitrous oxide/oxygen in rats1818 .Bessière B, Laboureyras E, Chateauraynaud J, Laulin JP, Simonnet G.
A single nitrous oxide (N2O) exposure leads to persistent alleviation of
neuropathic pain in rats. J Pain. 2010;11(1):13-23.
http://dx.doi.org/10.1016/j.jpain.2009.05.003
https://doi.org/10.1016/j.jpain.2009.05....
. This finding and the clinical observations are promising,
and the effect and mechanisms of pain alleviation by nitrous oxide need further
investigation.
Thus, the objective of this study was to investigate the effect of nitrous/oxygen in chronic pain of patients that were under dental treatment.
METHOD
Subjects
The dental profiles of 77 patients were included in this longitudinal retrospective research. They had been treated at the dental office under conscious sedation with nitrous oxide/oxygen March 2003 and April 2010. These patients were included because they presented in their anamnesis complaint of chronic pain in some part of their body for more than 6 months, which was part of their medical history. They had complete profiles including the location and intensity of pain by the visual analogue scale, which had been aplied immediately before and immediately after the complete dental treatment. The patients that needed more than one session of sedation had their pain measured before the first session and after the last one. The duration of pain relief was not assessed.
The patients were 43 (44.8%) women and the mean age was 58.1 ± 10.6 (20-83) years old. This study was approved by the Ethics Committee of our institution.
Dental treatments and conscious sedation
All patients had been evaluated and treated by the same trained dentist. The treatment included dental extractions, endodontic treatment, surgeries, periodontal scalling and all received information about oral hygiene. The mean number of dental sessions was 3.9 ± 2.6 (1-11). The interval between the sessions was 2-3 days. The mean nitrous oxide proportion was 2.5 ± 0.6 units and the mean oxygen proportion was 3.7 ± 0.7 units. All had their arterial blood pressure, heart rate and oxygen rate monitored during conscious sedation. The portable gases mixture was equipped with a sound system that avoided inadequate dosage of nitrous oxide (higher than oxygen).
Initially, the mask to administrate the gases was placed at the face of the patient. The proportions of nitrous oxide/oxygen were applied considering the following safety parameters and the individual variability of sensitivity to this technique: the majority of cases are able to inhale 50% of each (3 L/min of nitrous oxide and 3 L/min oxygen), part of patients are able to inhale 33% (2 L/min nitrous oxide and 4 L/min oxygen) and few patients are able to inhale only 16.7% (1 L/min nitrous nitrous oxide and 5 L/min oxygen). All procedures started with 6L/min of oxygen and after each 3 minutes, ½ L/min of nitrous oxide was increased. The report by the patient of peripheral tingling (hands and feet) and or the blood parameters were the factors to determine the interruption in the increase of nitrous oxide proportions, and the limit was 3 L/min nitrous oxide to 3 L/ min oxygen. After the dental treatment, the proportion of nitrous oxide was gradually reduced until only oxygen was administered for 3 to 5 minutes and the patients reported no symptoms of sedation. During all the procedure, the patients remained conscious with the protective reflexes (swallowing and cough), breathing, sensation of physical stimuli and talking with the dentist.
Statistical analysis
The sample consisted of all patients from a dental clinic that had been treated with conscious sedation with nitrous oxide/oxygen. All data were tabled and the means, standard deviations, frequencies and percentages were computed. After the initial descriptive analysis, the data were tested with Shapiro-Wilk e QQ plots in order to investigate normal distribution. The tests used for associations and differences between pre and post treatment data were oneway ANOVA, Student’s, chi-square and Wilcoxon. Correlations were investigated with the Pearson’s coefficient. All statistical calculations were performed using SPSS 17.0 (SPSS Inc.,Illinois,USA). The level of significance was p < 0.05.
RESULTS
There was a decrease in the number of patients with pain complaints and in the intensity, which can be observed in Tables 1 and 2. The female gender was associated with the decrease in the number of patients with pain at the head (chi-square, p = 0.005), abdomen (chi-square, p = 0.002) and inferior or superior limbs (chi-square, p = 0.001).
Correlations
The decrease in pain intensity after the treatment with sedation was higher in patients that were older (Pearson’s coefficient, p = 0.015). Patients with body pain and high intensity showed more dental pain during treatment and needed high proportion of nitrous oxide (Pearson’s coefficient, p = 0.037). Finally, patients that needed few sessions received high proportions of nitrous oxide/oxygen (Figure).
Negative correlation between the proportion of nitrous oxide / oxygen and the number of sessions (Pearson’s coefficient, p = 0.026).
DISCUSSION
This study showed evidence of remarkable reduction of chronic body pain complaints in patients that underwent dental treatment with conscious sedation with sedation with nitrous oxide/oxygen. This reduction was not associated with the location of pain, but according to the gender and ages. Women had more pain relief than men, and the older patients had higher decrease in pain intensity than the younger ones.
The doses of analgesic drugs can be reduced after the use of nitrous oxide during
surgical procedures44 .Echevarría G, Elgueta F, Fierro C, Bugedo D, Faba G, Iñiguez-Cuadra
R et al. Nitrous oxide (N(2)O) reduces postoperative opioid-induced hyperalgesia
after remifentanil-propofol anaesthesia in humans. Br J Anaesth.
2011;107(6):959-65. http://dx.doi.org/10.1093/bja/aer323
https://doi.org/10.1093/bja/aer323...
,55 .Stiglitz DK, Amaratunge LN, Konstantatos AH, Lindholm DE.
Intraoperative nitrous oxide as a preventive analgesic. Anaesth Intensive Care.
2010;38(5):890-3.,66 .Soumpasis I, Kanakoudis F, Vretzakis G, Arnaoutoglou E, Stamatiou
G, Iatrou C. Deep anaesthesia reduces postoperative analgesic requirements after
major urological procedures. Eur J Anaesthesiol. 2010;27(9):801-6.
http://dx.doi.org/10.1097/EJA.0b013e328337cbf4
https://doi.org/10.1097/EJA.0b013e328337...
,77 .Yuxiang L, Lu T, Jianqiang Y, Xiuying D, Wanfang Z, Wannian Z et
al. Analgesia effect of a fixed nitrous oxide/oxygen mixture on burn dressing
pain: study protocol for a randomized controlled trial. Trials. 2012;13(1):67.
http://dx.doi.org/10.1186/1745-6215-13-67
https://doi.org/10.1186/1745-6215-13-67...
,88 .Duma A, Helsten D, Brown F, Bottros MM, Nagele P. The effect of
nitrous oxide anesthesia on early postoperative opioid consumption and pain. Reg
Anesth Pain Med. 2014;39(1):31-6.
http://dx.doi.org/10.1097/AAP.0000000000000039
https://doi.org/10.1097/AAP.000000000000...
,99 .Ko H, Kaye AD, Urman RD. Nitrous oxide and perioperative outcomes.
J Anesth. 2014;28(3):420-8.
http://dx.doi.org/10.1007/s00540-013-1729-y
https://doi.org/10.1007/s00540-013-1729-...
,1010 .Chan MT, Wan AC, Gin T, Leslie K, Myles PS. Chronic postsurgical
pain after nitrous oxide anesthesia. Pain. 2011;152(11):2514-20.
http://dx.doi.org/10.1016/j.pain.2011.07.015
http://dx.doi.org/10.1016/j.pain.2011.07...
,1111 .Kavanagh T, Buggy DJ. Can anaesthetic technique effect
postoperative outcome? Curr Opin Anaesthesiol. 2012;25(2):185-98.
http://dx.doi.org/10.1097/ACO.0b013e32834f6c4c
http://dx.doi.org/10.1097/ACO.0b013e3283...
,1212 .Del Valle Rubido C, Solano Calvo JA, Miguel AR, Delgado Espeja JJ,
González Hinojosa J, Zapico Goñi Á. Inhalatory analgesia with nitrous oxide vs.
other analgesic techniques in hysteroscopic polypectomy: pilot study. J Minim
Invasive Gynecol. Forthcoming 2015.,1313 .Yokoe C, Hanamoto H, Sugimura M, Morimoto Y, Kudo C, Niwa H. A
prospective, randomized controlled trial of conscious sedation using propofol
combined with inhaled nitrous oxide for dental treatment. J Oral Maxillofac
Surg. 2015;73(3):402-9.
http://dx.doi.org/10.1016/j.joms.2014.09.014
https://doi.org/10.1016/j.joms.2014.09.0...
,1414 .Manouchehrian N, Bakhshaei MH. Nitrous oxide effect on relieving
anxiety and pain in parturients under spinal anesthesia for caesarean section.
Anesth Pain Med. 2014;4(2):e16662.
http://dx.doi.org/10.5812/aapm.16662
https://doi.org/10.5812/aapm.16662...
. The development of chronic pain after surgeries can also
be prevented with this type of sedation1717 .Chaparro LE, Smith SA, Moore RA, Wiffen PJ, Gilron I.
Pharmacotherapy for the prevention of chronic pain after surgery in adults.
Cochrane Database Syst Rev. 2013;7:CD008307.
http://dx.doi.org/10.1002/14651858.CD008307.pub2
https://doi.org/10.1002/14651858.CD00830...
. However, this is the first study that had showed the
effect of nitrous oxide in pain alleviation of chronic symptoms and not in the use
as intraoperative anesthetic technique1010 .Chan MT, Wan AC, Gin T, Leslie K, Myles PS. Chronic postsurgical
pain after nitrous oxide anesthesia. Pain. 2011;152(11):2514-20.
http://dx.doi.org/10.1016/j.pain.2011.07.015
http://dx.doi.org/10.1016/j.pain.2011.07...
,1111 .Kavanagh T, Buggy DJ. Can anaesthetic technique effect
postoperative outcome? Curr Opin Anaesthesiol. 2012;25(2):185-98.
http://dx.doi.org/10.1097/ACO.0b013e32834f6c4c
http://dx.doi.org/10.1097/ACO.0b013e3283...
,1212 .Del Valle Rubido C, Solano Calvo JA, Miguel AR, Delgado Espeja JJ,
González Hinojosa J, Zapico Goñi Á. Inhalatory analgesia with nitrous oxide vs.
other analgesic techniques in hysteroscopic polypectomy: pilot study. J Minim
Invasive Gynecol. Forthcoming 2015.,1313 .Yokoe C, Hanamoto H, Sugimura M, Morimoto Y, Kudo C, Niwa H. A
prospective, randomized controlled trial of conscious sedation using propofol
combined with inhaled nitrous oxide for dental treatment. J Oral Maxillofac
Surg. 2015;73(3):402-9.
http://dx.doi.org/10.1016/j.joms.2014.09.014
https://doi.org/10.1016/j.joms.2014.09.0...
,1414 .Manouchehrian N, Bakhshaei MH. Nitrous oxide effect on relieving
anxiety and pain in parturients under spinal anesthesia for caesarean section.
Anesth Pain Med. 2014;4(2):e16662.
http://dx.doi.org/10.5812/aapm.16662
https://doi.org/10.5812/aapm.16662...
,1515 .Sun WZ. Anesthetic or analgesic effect of N2O in acute
pain model? Reg Anesth Pain Med. 2014;39(3):263.
http://dx.doi.org/10.1097/AAP.0000000000000081
https://doi.org/10.1097/AAP.000000000000...
,1616 .Merskey H, Bogduk N, editors. Classification of chronic pain:
descriptions of chronic pain syndromes and definitions of pain terms. 2nd ed.
Seattle: International Association for the Study of Pain; 1994.,1717 .Chaparro LE, Smith SA, Moore RA, Wiffen PJ, Gilron I.
Pharmacotherapy for the prevention of chronic pain after surgery in adults.
Cochrane Database Syst Rev. 2013;7:CD008307.
http://dx.doi.org/10.1002/14651858.CD008307.pub2
https://doi.org/10.1002/14651858.CD00830...
.
The mechanism underlying the analgesic effect of nitrous oxide seems to be its role
as an antagonist at the N-methyl-D-aspartate receptor, involved in pain
chronification1111 .Kavanagh T, Buggy DJ. Can anaesthetic technique effect
postoperative outcome? Curr Opin Anaesthesiol. 2012;25(2):185-98.
http://dx.doi.org/10.1097/ACO.0b013e32834f6c4c
http://dx.doi.org/10.1097/ACO.0b013e3283...
. Patients
with chronic pain show neuroplastic phenomena and altered neural processing that
involves NMDA receptors, and they can be a target for anesthesia and analgesic
effect that are systemic. In rats, a single exposure to nitrous oxide sedation was
capable of alleviate neuropathic pain for a long period, including the reduction of
thermal allodynia1010 .Chan MT, Wan AC, Gin T, Leslie K, Myles PS. Chronic postsurgical
pain after nitrous oxide anesthesia. Pain. 2011;152(11):2514-20.
http://dx.doi.org/10.1016/j.pain.2011.07.015
http://dx.doi.org/10.1016/j.pain.2011.07...
,1818 .Bessière B, Laboureyras E, Chateauraynaud J, Laulin JP, Simonnet G.
A single nitrous oxide (N2O) exposure leads to persistent alleviation of
neuropathic pain in rats. J Pain. 2010;11(1):13-23.
http://dx.doi.org/10.1016/j.jpain.2009.05.003
https://doi.org/10.1016/j.jpain.2009.05....
. Thus, nitrous oxide could be a tool in the treatment of
chronic pain conditions.
Nitrous oxide has been used in dentistry since the XIX century for analgesia and it
is a safe and effective technique for the control of anxiety and fear. It has been
shown that women at labor had less pain and fewer analgesics consume after delivery
when exposed to it1919 .Klomp T, van Poppel M, Jones L, Lazet J, Di Nisio M, Lagro-Janssen
AL. Inhaled analgesia for pain management in labour. Cochrane Database Syst Rev.
2012;9:CD009351.
http://dx.doi.org/10.1002/14651858.CD009351.pub2
https://doi.org/10.1002/14651858.CD00935...
. Its use is
regulated and the equipment must prevent proportions higher than 70% of N22 .Brunick A, Clark M. Nitrous oxide and oxygen sedation: an update.
Dent Assist. 2010;79:22-3, 26, 28-30; quiz 32, 34.O. Besides its effect in NMDA
receptors, the nitrous oxide may cause a release of endorphins and dopamine that
modulate the suppressive descendent pathways, however it seems that the relief of
chronic neuropathic pain in rats was more associated with the antagonic effect on
NMDA receptors1818 .Bessière B, Laboureyras E, Chateauraynaud J, Laulin JP, Simonnet G.
A single nitrous oxide (N2O) exposure leads to persistent alleviation of
neuropathic pain in rats. J Pain. 2010;11(1):13-23.
http://dx.doi.org/10.1016/j.jpain.2009.05.003
https://doi.org/10.1016/j.jpain.2009.05....
. More studies are
necessary to clarify the exact pathophysiological mechanism in chronic pain
patients, according to the diagnosis, establishing if they are the same as the
relief in acute postsurgical pain by nitrous oxide1919 .Klomp T, van Poppel M, Jones L, Lazet J, Di Nisio M, Lagro-Janssen
AL. Inhaled analgesia for pain management in labour. Cochrane Database Syst Rev.
2012;9:CD009351.
http://dx.doi.org/10.1002/14651858.CD009351.pub2
https://doi.org/10.1002/14651858.CD00935...
,2020 .Nesek-Adam V, Rasić Z, Schwarz D, Grizelj-Stojcić E, Rasić D,
Krstonijević Z et al. The effect of spinal versus general anesthesia on
postoperative pain and analgesic requirements in patients undergoing peripheral
vascular surgery. Coll Antropol. 2012;36(4):1301-5.. The role of sexual hormones, genetic differences and
aging need to be also investigated in order to understand the associations found.
Finally, the patients that were exposed to low proportions of nitrous oxide needed
more sessions for the dental treatment, and it is possible that there was a lack in
the analgesic effect because of concentration that turned into necessary new
appointments to finish the treatment. Therefore, future prospective studies are
necessary.
Some limitations of the application need to be further investigated. The sedation
with nitrous oxide may be associated with the long-term risk of myocardial
infarction, and thus the patients need to be carefully evaluated in order to
indicate this sedation only for those with none or low risks due to this
technique11 .Szymańska J. Environmental health risk of chronic exposure to
nitrous oxide in dental practice. Ann Agric Environ Med.
2001;8(2):119-22.,1818 .Bessière B, Laboureyras E, Chateauraynaud J, Laulin JP, Simonnet G.
A single nitrous oxide (N2O) exposure leads to persistent alleviation of
neuropathic pain in rats. J Pain. 2010;11(1):13-23.
http://dx.doi.org/10.1016/j.jpain.2009.05.003
https://doi.org/10.1016/j.jpain.2009.05....
. In elderly, other risks such as
cancer recurrence, neurotoxicity and long-term cognitive dysfunction need to be
investigated and considered.
In conclusion, chronic pain at other parts of the body of patients that underwent dental treatment with nitrous oxide sedation presented a reduction in their intensity. It was not dependent on the local of pain and more often in women. Nitrous oxide may be a tool to be used in the treatment of chronic pain, and future prospective studies are necessary to understand the underlying mechanisms and the effect of nitrous oxide/oxygen in patients according to the pain diagnosis and other characteristics.
References
-
1Szymańska J. Environmental health risk of chronic exposure to nitrous oxide in dental practice. Ann Agric Environ Med. 2001;8(2):119-22.
-
2Brunick A, Clark M. Nitrous oxide and oxygen sedation: an update. Dent Assist. 2010;79:22-3, 26, 28-30; quiz 32, 34.
-
3Daher A, Hanna RP, Costa LR, Leles CR. Practices and opinions on nitrous oxide/oxygen sedation from dentists licensed to perform relative analgesia in Brazil. BMC Oral Health. 2012;12(1):21. http://dx.doi.org/10.1186/1472-6831-12-21
» https://doi.org/10.1186/1472-6831-12-21 -
4Echevarría G, Elgueta F, Fierro C, Bugedo D, Faba G, Iñiguez-Cuadra R et al. Nitrous oxide (N(2)O) reduces postoperative opioid-induced hyperalgesia after remifentanil-propofol anaesthesia in humans. Br J Anaesth. 2011;107(6):959-65. http://dx.doi.org/10.1093/bja/aer323
» https://doi.org/10.1093/bja/aer323 -
5Stiglitz DK, Amaratunge LN, Konstantatos AH, Lindholm DE. Intraoperative nitrous oxide as a preventive analgesic. Anaesth Intensive Care. 2010;38(5):890-3.
-
6Soumpasis I, Kanakoudis F, Vretzakis G, Arnaoutoglou E, Stamatiou G, Iatrou C. Deep anaesthesia reduces postoperative analgesic requirements after major urological procedures. Eur J Anaesthesiol. 2010;27(9):801-6. http://dx.doi.org/10.1097/EJA.0b013e328337cbf4
» https://doi.org/10.1097/EJA.0b013e328337cbf4 -
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» https://doi.org/10.1186/1745-6215-13-67 -
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Publication Dates
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Publication in this collection
July 2015
History
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Received
15 Dec 2014 -
Reviewed
13 Feb 2015 -
Accepted
05 Mar 2015