The environmental impact of nitrous oxide inhalation sedation appointments and equipment used in dentistry

PURPOSE

This paper reports a life cycle impact assessment (LCIA) to calculate the environmental footprint of a dental appointment using N2O, comparing single-use equipment with reusable equipment. Nitrous oxide (N2O) is used successfully in dentistry to provide sedation and pain relief to anxious patients, most commonly in children. However, N2O is a powerful climate pollutant 298 times more damaging than carbon dioxide over a 100-year estimate.

METHODS

The functional unit chosen for this LCIA was 30 min delivery of N2O to oxygen in a 50:50 ratio at 6 L per minute flow rate as inhalation sedation to one patient. Two types of equipment were compared to deliver the anaesthetic gas: reusable and disposable items.

RESULTS

The use of disposable equipment for N2O sedation produces a significantly larger environmental impact across nearly all of the environmental impact scores, but the overall global warming potential is comparable for both types of equipment due to the vast environmental pollution from N2O itself.

CONCLUSION

N2O sedation is a reliable treatment adjunct but contributes to climate change. Single-use equipment has a further deleterious effect on the environment, though this is small compared to the overall impact of N2O. Dental priorities should be to deliver safe and effective care to patients that protects staff, minimises waste and mitigates impact on the environment alongside promoting research into alternatives.

Guidelines for inhaled sedation in the ICU

INTRODUCTION AND OBJECTIVES

Sedation is used in intensive care units (ICU) to improve comfort and tolerance during mechanical ventilation, invasive interventions, and nursing care. In recent years, the use of inhalation anaesthetics for this purpose has increased. Our objective was to obtain and summarise the best evidence on inhaled sedation in adult patients in the ICU, and use this to help physicians choose the most appropriate approach in terms of the impact of sedation on clinical outcomes and the risk-benefit of the chosen strategy.

METHODOLOGY

Given the overall lack of literature and scientific evidence on various aspects of inhaled sedation in the ICU, we decided to use a Delphi method to achieve consensus among a group of 17 expert panellists. The processes was conducted over a 12-month period between 2022 and 2023, and followed the recommendations of the CREDES guidelines.

RESULTS

The results of the Delphi survey form the basis of these 39 recommendations - 23 with a strong consensus and 15 with a weak consensus.

CONCLUSION

The use of inhaled sedation in the ICU is a reliable and appropriate option in a wide variety of clinical scenarios. However, there are numerous aspects of the technique that require further study.

Comparative Assessment of Anxiety during Inferior Alveolar Nerve Block under Nitrous Oxide + Oxygen and Oxygen Inhalation Sedation in Children Aged 3-12 Years: A Randomized Clinical Trial

Aim

A comparative evaluation of children's anxiety with the use of nitrous oxide-oxygen (N2O-O2) inhalation sedation during the administration of inferior alveolar nerve block (IANB).

Materials and methodology

A total of 60 children between 3 and 12 years of age, with Frankl's behavior rating of 2-3 requiring IANB for any dental procedure were enrolled in this randomized clinical study. Group I (n = 30) received N2O and oxygen inhalation sedation at a concentration in the range of 25-50%, whereas group II (n = 30) received 100% O2 as a placebo. The physiological parameters like pulse rate, respiration, blood pressure, and O2 saturation were measured at the baseline, intraoperatively [during and after administration of local anesthesia (LA)] and postoperatively after the termination of the gases in both groups. The sedation level was measured intraoperatively (before administration of LA) using the Ramsay Sedation Score (RSS). The discomfort and anxiety were measured at the baseline, intraoperatively, and postoperatively using the Face, Legs, Activity, Cry, Consolability (FLACC) behavior scale. The data were evaluated using the statistical software International Business Machines (IBM) Statistical Package for the Social Sciences (SPSS) statistics 20.0.

Results

There was a significant difference in the FLACC scores between the two groups, intraoperatively (p-value-0.002), and postoperatively (p-value-0.049). The mean of the RSS for group I was 2.80 + 1.03, and for group II was 1.80 + 0.81. All the physiological parameters recorded were within the normal range.

Conclusion

The use of N2O-O2 inhalation improved the anxiety levels in children while receiving the IANB and showed significant anxiolytic and sedative effects as compared to O2 inhalation.

Clinical significance

Nitrous oxide-oxygen (N2O-O2) inhalation can be used as a nonpharmacological behavior management adjunct for invasive treatments for children with utmost comfort for the child.

How to cite this article

Thomas PS, Dave BH, Shah DJ, et al. Comparative Assessment of Anxiety during Inferior Alveolar Nerve Block under Nitrous Oxide + Oxygen and Oxygen Inhalation Sedation in Children Aged 3-12 Years: A Randomized Clinical Trial. Int J Clin Pediatr Dent 2023;16(1):30-36.

Nitrous Oxide Inhalation Sedation Rapid Analgesia in Dentistry: An Overview of Technique, Objectives, Indications, Advantages, Monitoring, and Safety Profile

Nitrous oxide inhalation sedation (NOIS) has been the backbone of anxiety alleviation in dentistry for a long time. Advantages of nitrous oxide (N2O) include anxiolysis, mild analgesia, and amnesia. It also has the ability to raise the patient pain threshold, providing rapid analgesia (RA), thus enhancing the action of any local anesthesia used. This paper describes the technique of NOIS in detail and highlights its objectives, advantages, indications, monitoring, and safety profile. Other than the specialty of pediatric dentistry, this paper also highlights the applications and merits of NOIS in adult, geriatric, and special healthcare needs dentistry. Away from dentistry, it also brings to light the multidisciplinary applications of NOIS in other medical streams. This review could be a valuable interpretation on the present position of N2O sedation in dentistry and a valuable starting point for future perspectives.

How to cite this article

Khinda V, Rao D, Singh Sodhi SP. Nitrous Oxide Inhalation Sedation Rapid Analgesia in Dentistry: An Overview of Technique, Objectives, Indications, Advantages, Monitoring, and Safety Profile. Int J Clin Pediatr Dent 2023;16(1):131-138.

Isoflurane vs. propofol for sedation in invasively ventilated patients with acute hypoxemic respiratory failure: an a priori hypothesis substudy of a randomized controlled trial

BACKGROUND

Acute hypoxemic respiratory failure (AHRF) is a leading concern in critically ill patients. Experimental and clinical data suggest that early sedation with volatile anesthestics may improve arterial oxygenation and reduce the plasma and alveolar levels of markers of alveolar epithelial injury and of proinflammatory cytokines.

METHODS

An a priori hypothesis substudy of a multicenter randomized controlled trial (The Sedaconda trial, EUDRA CT Number 2016-004551-67). In the Sedaconda trial, 301 patients on invasive mechanical ventilation were randomized to 48 h of sedation with isoflurane or propofol in a 1:1 ratio. For the present substudy, patients with a ratio of arterial pressure of oxygen (PaO₂) to inspired fraction of oxygen (FiO₂), PaO₂/FiO₂, of ≤ 300 mmHg at baseline were included (n = 162). The primary endpoint was the change in PaO₂/FiO₂ between baseline and the end of study sedation. A subgroup analysis in patients with PaO₂/FiO₂ ≤ 200 mmHg was performed (n = 82).

RESULTS

Between baseline and the end of study sedation (48 h), oxygenation improved to a similar extent in the isoflurane vs. the propofol group (isoflurane: 199 ± 58 to 219 ± 76 mmHg (n = 70), propofol: 202 ± 62 to 236 ± 77 mmHg (n = 89); p = 0.185). On day seven after randomization, PaO₂/FiO₂ was 210 ± 79 mmHg in the isoflurane group (n = 41) and 185 ± 87 mmHg in the propofol group (n = 44; p = 0.411). In the subgroup of patients with PaO₂/FiO₂ ≤ 200 mmHg, PaO₂/FiO₂ increase between baseline and end of study sedation was 152 ± 33 to 186 ± 54 mmHg for isoflurane (n = 37), and 150 ± 38 to 214 ± 85 mmHg for propofol (n = 45; p = 0.029). On day seven, PaO₂/FiO₂ was 198 ± 69 mmHg in patients randomized to isoflurane (n = 20) and 174 ± 106 mmHg in patients randomized to propofol (n = 20; p = 0.933). Both for the whole study population and for the subgroup with PaO₂/FiO₂ ≤ 200 mmHg, no significant between-group differences were observed for PaCO₂, pH and tidal volume as well as 30-day mortality and ventilator-free days alive.

CONCLUSIONS

In patients with AHRF, inhaled sedation with isoflurane for a duration of up to 48 h did not lead to improved oxygenation in comparison to intravenous sedation with propofol. Trial registration The main study was registered in the European Medicines Agency's EU Clinical Trial register (EudraCT), 2016-004551-67, before including the first patient. The present substudy was registered at German Clinical Trials Register (DRKS, ID: DRKS00018959) on January 7th, 2020, before opening the main study data base and obtaining access to study results.

Nitrous oxide inhalation sedation in dentistry: An overview of its applications and safety profile

Nitrous oxide in oxygen (N₂O/O₂) inhalation sedation is used less commonly by Singapore dentists than their counterparts in the United Kingdom and the United States. Using this technique, trained dentists often perform the dual roles of a sedationist and an operating dentist. This paper describes the mechanism of action of N₂O and highlights the modern gas delivery system commonly used in dentistry. The built-in safety features of this unique system helps to ensure that patient-specific therapeutic dosages are effectively and safely administered by dentists. Existing evidence for adverse events and the safety profile of the N₂O/O₂ inhalation sedation is discussed. Finally, recommendations of equipment, training and techniques for safe N₂O/O₂ inhalation sedation are provided.

Halving the volume of AnaConDa: initial clinical experience with a new small-volume anaesthetic reflector in critically ill patients-a quality improvement project

AnaConDa-100 ml (ACD-100, Sedana Medical, Uppsala, Sweden) is well established for inhalation sedation in the intensive care unit. But because of its large dead space, the system can retain carbon dioxide (CO₂) and increase ventilatory demands. We therefore evaluated whether AnaConDa-50 ml (ACD-50), a device with half the internal volume, reduces CO₂ retention and ventilatory demands during sedation of invasively ventilated, critically ill patients. Ten patients participated in this cross-over protocol. After sedation with isoflurane via ACD-100 for 24 h, the 5-h observation period started. During the first hour, ACD-100 was used; for the next 2 h, ACD-50; and for the last 2 h, ACD-100 was used again. Sedation was titrated to Richmond Agitation and Sedation Scale (RASS) score - 3 to - 4 and a processed electroencephalogram (Narcotrend Index, Narcotrend-Gruppe, Hannover, Germany) was recorded. Minute ventilation, CO₂ elimination, and isoflurane consumption were compared. All patients were deeply sedated (Narcotrend Index, mean ± SD: 38 ± 10; RASS scores - 3 to - 5) and breathed spontaneously with pressure support throughout the observation period. Infusion rates of isoflurane and opioid, either remifentanil or sufentanil, as well as ventilator settings were unchanged. Minute ventilation and end-tidal CO₂ were significantly reduced with the ACD-50, respiratory rate remained unchanged, and tidal volume decreased by 66 ± 43 ml. End-tidal isoflurane concentrations were also slightly reduced while haemodynamic measures remained constant. The ACD-50 reduces the tidal volume needed to eliminate carbon dioxide without augmenting isoflurane consumption.

Treatment outcomes of using inhalation sedation for comprehensive dental care

Aim

To assess the outcomes of dental treatment under inhalation sedation within a UK specialist hospital setting.

Methods

This was a retrospective cohort study of the case notes of patients under 17 years of age who received dental treatment using inhalation sedation at a UK specialist setting during the period 2006–2011. Treatment outcomes were categorised into five groups: (1) treatment completed as planned, (2) modified treatment completed, (3) treatment abandoned in sedation unit and patient referred for treatment under general analgesia (GA), (4) treatment abandoned in sedation unit and patient referred for treatment under local analgesia (LA), (5) child failed to return to complete treatment.

Results

In total, the case notes of 453 patients were evaluated. The mean age of the patients was 10.3 ± 2.9 years. Treatment was completed successfully in 63.6% of the cases, 15.9% were referred for treatment under GA, 11.2% failed to return to complete the treatment, 7.1% received modified treatment completed, and only 2.2% were referred for treatment under LA. Treatment outcomes were significantly associated with patient`s age (p = 0.002). The treatment outcome “treatment abandoned and child referred to be treated under GA” had significantly lower mean patient ages than the other outcomes.

Conclusions

The majority of children referred for inhalation sedation, completed their course of treatment. A significantly higher proportion of those in the younger age group required GA to complete their treatment.

[New technical developments for inhaled sedation]

The circle system has been in use for more than 100 years, whereas the first clinical application of an anaesthetic reflector was reported just 15 years ago. In the circle system, all breathing gas is rebreathed after carbon dioxide absorption. A reflector, on the other hand, with the breathing gas flowing to and fro, specifically retains the anaesthetic during expiration and resupplies it during the next inspiration. A high reflection efficiency (number of molecules resupplied/number of molecules exhaled, RE 80-90%) decreases consumption. In analogy to the fresh gas flow of a circle system, pulmonary clearance ((1-RE) × minute ventilation) defines the opposition between consumption and control of the concentration.It was not until reflection systems became available that volatile anaesthetics were used routinely in some intensive care units. Their advantages, such as easy handling, and better ventilatory capabilities of intensive care versus anaesthesia ventilators, were basic preconditions for this. Apart from AnaConDa™ (Sedana Medical, Uppsala, Sweden), the new MIRUS™ system (Pall Medical, Dreieich, Germany) represents a second, more sophisticated commercially available system.Organ protective effects, excellent control of sedation, and dose-dependent deep sedation while preserving spontaneous breathing with hardly any accumulation or induction of tolerance, make volatile anaesthetics an interesting alternative, especially for patients needing deep sedation or when intravenous drugs are no longer efficacious.But obviously, the outcome is most important. We know that deep intravenous sedation increases mortality, whereas inhalational sedation could prove beneficial. We now need prospective clinical trials examining mortality, but also the psychological outcome of those most critically ill patients sedated by inhalation or intravenously.

Evaluation of transcutaneous and end-tidal carbon dioxide levels during inhalation sedation in volunteers

Measurement of end-tidal carbon dioxide (PETCO2) is useful because of its noninvasiveness, continuity, and response time when sudden changes in ventilation occur during inhalation sedation. We compared the accuracy of PETCO2 using a nasal mask and nasal cannula with the accuracy of transcutaneous carbon dioxide (TC-CO2) and determined which method is more useful during inhalation sedation in volunteers. We used a modified nasal mask (MNM) and modified nasal cannula (MNC) for measurement of PETCO2. The capnometer measured PETCO2 in the gas expired from the nasal cavity by means of two devices. The volunteers received supplemental O2 by means of each device at a flow rate of 6 L/min. After the volunteers lay quietly for 5 min with a supply of 100 % O2, they received supplemental N2O by means of each device at concentrations of 10, 20, and 25 % for 5 min and 30 % for 25 min. The correlation coefficient was poorer in the MNM than in the MNC, and the mean difference between TC-CO2 and PETCO2 in the MNM was greater than that in the MNC. The difference between the TC-CO2 and PETCO2 ranged from 3 to 6 mmHg in the MNM and from 2 to 5 mmHg in the MNC. The difference between two variables against the TC-CO2 and the CO2 waveforms obtained by means of the two devices were within the clinically acceptable range. Our two devices can provide continuous monitoring of PETCO2 with a supply of N2O/O2 in patients undergoing inhalation sedation.

Health worker exposure risk during inhalation sedation with sevoflurane using the (AnaConDa®) anaesthetic conserving device

INTRODUCTION AND OBJECTIVE

Occupational exposure to sevoflurane should not exceed 2 ppm. During inhalation sedation with sevoflurane using the anaesthetic conserving device (AnaConDa(®)) in the post-anaesthesia care unit, waste gases can be reduced by gas extraction systems or scavenging devices such as CONTRAfluran™. However, the efficacy of these methods has not been clearly established. To determine the safest scenario for healthcare workers during inhalation sedation with sevoflurane in the post-surgical intensive care unit.

MATERIALS AND METHODS

An experimental study on occupational exposure was conducted in a post-cardiothoracic care unit during March-August 2009. The measurements were performed in four post-cardiac surgery sedated adults in post-surgical intensive care unit and four nurses at the bedside, and at four points: scenario A, inhalation sedation without gas extraction system or contrafluran as a reference scenario; scenario B, applying a gas extraction system to the ventilator; scenario C, using contrafluran; and scenario 0, performing intravenous isolation sedation. Sevoflurane concentrations were measured in the nurses' breathing area during patient care, and at 1.5 and 8 m from the ventilator using diffusive passive monitor badges.

RESULTS

All badges corresponding to the nurses' breathing area were below 2 ppm. Levels of sevoflurane detected using prevention systems were lower than that in the control situation. Only one determination over 2 ppm was found, corresponding to the monitor placed nearest the gas outlet of the ventilator in scenario A. Trace concentrations of sevoflurane were found in scenario 0 during intravenous sedation.

CONCLUSIONS

Administration of sevoflurane through the AnaConDa(®) system during inhalation sedation in post-surgical intensive care units is safe for healthcare workers, but gas extraction systems or scavenging systems, such as CONTRAfluran™ should be used to reduce occupational exposure as much as possible.