Arterial blood gases before, during, and after nitrous oxide: Oxygen administration

doi:10.1016/S0196-0644(86)80861-7

Annals of Emergency Medicine

Volume 15, Issue 10, October 1986, Pages 1177-1180

https://doi.org/10.1016/S0196-0644(86)80861-7 Get rights and content

The use of nitrous oxide as an anesthetic or analgesic agent frequently raises concerns about the possibility of post-inhalational diffusion hypoxemia. We undertook a study in 20 healthy volunteers to determine whether hypoxemia occurs after the self-administration by face mask of a 50:50 mixture of nitrous oxide and oxygen for 15 minutes, followed by breathing room air. Blood gases were measured through an in-dwelling arterial cannula before, during, and after inhalation of the mixture, at time O, five, ten, and 15 minutes, and then 30 seconds, 45 seconds, 2½ minutes, five, and ten minutes following room air breathing. Ten of the 20 subjects breathed a control gas, a mixture of 50% nitrogen:50% oxygen. No subject demonstrated arterial hypoxemia at any time before, during, or after self-administration of the gas mixture. In the ten subjects who self-administered the control gas there were no significant differences in the PaO₂ values while they breathed either gas at any corresponding sampling time. We conclude that diffusion hypoxia is not seen in normal subjects following self-administration of a mixture of 50:50 nitrous oxide and oxygen.

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Cited by (18)

Interventions to reduce arterial puncture-related pain: A systematic review and meta-analysis
2022, International Journal of Nursing Studies
Citation Excerpt :
The screening of titles and abstracts led to the identification and removal of 932 duplicates and the inclusion of 46 articles into the full text review process. Twelve (Bates and Cutting, 2001, Wendler, 2003, Çelik et al., 2011, Chauvin et al., 2020, Chvetzoff, 2006, Dawson and Hogg, 2005, Eslami et al., 2020, Li et al., 2016, McSwain and Yeager, 2015, Ouadhour et al., 2008, Pouso Garrido, 2017, Stewart et al., 2021) did not meet the inclusion criteria and were excluded (Table A2, Appendix 1). The manual review of included papers revealed nine additional articles, thus 43 articles were included in the systematic review (Fig. 1).
Arterial puncture-related pain remains unaddressed across several clinical settings. Analgesic techniques are not routinely employed before arterial puncture despite the recommendation that local anesthesia be used, except in emergencies. A comprehensive review of interventions aimed at reducing arterial puncture-related pain and their potential effectiveness is lacking, and the benefit of some interventions is uncertain.
To describe interventions aimed at reducing arterial puncture-related pain and provide an estimate of their effectiveness.
Systematic review and meta-analysis (PROSPERO no. CRD42020212299).
PubMed, CINAHL EBSCO, EMBASE, the Cochrane Database of Systematic Reviews, and Scopus were searched from their inception to 7 October 2020. No temporal or language limits were applied.
Published, quantitative studies on interventions aimed at reducing arterial puncture-related pain among adults were included. Screening, quality appraisal, and data extraction were undertaken independently by two reviewers. Random effects meta-analyses were performed to assess the association between interventions aimed at reducing arterial puncture-related pain and patients’ perceived pain using difference in means (MD) with 95% confidence intervals (CIs). A funnel plot and Egger test were used to assess publication bias.
The titles and abstracts of the 2446 identified articles were screened, and 43 and 31 studies were finally included in the systematic review and meta-analysis, respectively. Interventions to reduce arterial puncture-related pain included: topical anesthetics (n = 16), cryotherapy (n = 9), local anesthetic infiltration (n = 5), narrower needle gage (n = 5), ultrasound-guided procedure (n = 3), topical anesthetics combined with local anesthetic infiltration (n = 1), iontophoresis using anesthetics (n = 1), engineered blood gas syringe (n = 1), jet injector (n = 1), and local massage (n = 1). Topical anesthetics [MD -0.58, 95% CI -1.00, -0.15], cryotherapy [MD -1.13, 95% CI -1.72, -0.53], and local anesthetic infiltration [MD -1.13, 95% CI -1.72, -0.53] reduced arterial puncture-related pain. No benefit was found for narrower needle gage [MD -0.07, 95% CI -0.86, 0.71] or ultrasound-guided procedure [MD -1.74, 95% CI -3.51, 0.03]. No publication bias was detected.
Local anesthetic infiltration provided the greatest pain reduction and should be considered standard practice. Cryotherapy may be a safe, convenient alternative to local anesthetic infiltration. Topical anesthetics had limited benefit, and their lengthy time of onset makes them unsuitable for critical or emergency situations, though they may represent an option when comorbid conditions make cooling impossible. Caution must be used when interpreting these results, given the high risk of bias in the methods of included studies and the heterogeneity across the studies.
The opioid-P2Y<inf>12</inf> inhibitor interaction: Potential strategies to mitigate the interaction and consideration of alternative analgesic agents in myocardial infarction
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Despite advances in medical and interventional management of acute myocardial infarction, treatment of the associated chest pain has remained relatively unchanged since opioids were first utilized in the 1930’s. This dominance can be partially attributed to initial studies suggesting hemodynamic benefits with opioid treatment. However, delayed gastrointestinal absorption of P2Y₁₂ inhibitors due to opioids and the consequent impairment in antiplatelet activity of this established therapy is cause for concern. Coupled with the lack of randomized clinical trial evidence to support widespread opioid use, there is now an opportunity to re-evaluate our approach to analgesia in myocardial infarction. This review characterizes the mechanism of the opioid-P2Y₁₂ inhibitor interaction, strategies aimed at mitigating the interaction and appraises promising alternative agents to opioid therapy in patients with myocardial infarction.
Clinical Policy: Critical Issues in the Sedation of Pediatric Patients in the Emergency Department
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Clinical Policy: Critical Issues in the Sedation of Pediatric Patients in the Emergency Department
2008, Annals of Emergency Medicine
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N2O has both opioid agonist and N-methyl-D-aspartate (NMDA) glutamate receptor antagonist effects.53,54 In healthy patients, N2O has minimal cardiovascular or respiratory effects;55-57 however, it may enhance the depressed response to hypoxia and hypercarbia induced by other agents.55-59 Onset and offset of effects occur within 5 minutes, and N2O does not require vascular access or painful administration.
Nitrous oxide for colonoscopy: A randomized controlled study
2000, Gastrointestinal Endoscopy
Background: Intravenous sedation/analgesia for colonoscopy is accompanied with certain risks and postprocedure drowsiness. We sought to determine whether inhaled nitrous oxide (Entonox: 50% nitrous oxide, 50% oxygen) provides adequate analgesia for colonoscopy and the impact of this agent on recovery. Methods: All patients undergoing outpatient colonoscopy were considered for the study (n = 248) except those with previous colonic resection. Data for patients unsuitable for randomization (n = 58) and those who declined to participate (n = 88) were also analyzed. Results: One hundred two patients were randomized to receive inhaled Entonox alone (n = 56) or intravenous midazolam and meperidine (n = 46). Forty-nine (88%) patients randomized to Entonox underwent complete colonoscopy without conversion to intravenous medications. Entonox patients reported more pain (p < 0.0001), tolerated colonoscopy less well (p < 0.0001), were less satisfied (p = 0.01), and less willing to undergo colonoscopy again under the same circumstances (p = 0.04). Of patients receiving intravenous medication, 91% found colonoscopy less unpleasant and 9% as unpleasant as anticipated; this compares with 52% and 21% Entonox patients, respectively, and an additional 27% Entonox patients who found colonoscopy more unpleasant than anticipated. Recovery was faster among Entonox patients (median 30 versus 60 minutes, p < 0.0001). Conclusion: Entonox is less effective than midazolam with meperidine for colonoscopy but is acceptable in many patients and allows faster recovery. (Gastrointest Endosc 2000;51:271-7.)
Flexible sigmoidoscopy
1997, Primary Care - Clinics in Office Practice
The flexible sigmoidoscope is a flexible fiberoptic or video endoscope designed to examine the mucosal surface of the sigmoid colon and rectum. The flexible sigmoidoscope represents a technologic advancement over the earlier rigid sigmoidoscopes that were hindered by the relatively short length of bowel they could visualize and the rather uncomfortable examination the patient was required to endure in its use. The technical design of the flexible sigmoidoscope provides a more comfortable examination for the patient, and the longer length of the scope allows for the evaluation of more of the colon with the potential for the detection of a greater number of lesions. Studies have shown its superiority over the rigid sigmoidoscope in terms of patient discomfort, anxiety, and compliance.²⁴ Also, studies have shown the ability of the flexible scope to detect a significantly greater number of malignant and premalignant lesions compared with the rigid instrument.²³
The flexible sigmoidoscope has clinical usefulness in the evaluation of many disease processes that involve the rectum and sigmoid colon. Many consider it the primary diagnostic modality for examination of the rectosigmoid. In addition, the role of flexible sigmoidoscopy in screening asymptomatic individuals for neoplastic lesions of the colon and rectum, although not completely defined at this time, appears to be expanding. The proximal migration of colorectal neoplastic lesions has created a need to rely on detection methods that examine greater lengths of colon. As this need grows and as technical improvements in sigmoidoscope design and imaging capabilities continue, the utilization of the flexible sigmoidoscope should expand.

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: Presented at the University Association for Emergency Medicine Annual Meeting in Kansas City, Missouri, May 1985.

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Original contributionArterial blood gases before, during, and after nitrous oxide: Oxygen administration

Ann Emerg Med

Ann Emerg Med

Ann Emerg Med

Self-administered analgesia with nitrous oxide. Adjunctive aid for emergency medical care systems

JAMA

Patient-controlled inhalational analgesia in prehospital care: A study of side-effects and feasibility

Crit Care Med

An assessment of the oxygen tension obtained with pre-mixed 50% nitrous oxide and oxygen mixture (Entonox) used for pain relief

Anaesthesia

Diffusion anoxia

Anesthesiology

Original contribution
Arterial blood gases before, during, and after nitrous oxide: Oxygen administration