**6. Conclusions**

For the range of injection pressures equal to the hydraulic fracturing pressure:

**•** Greater injection rates result in a smaller shear stimulated surface area. The results indicate that once the HF is formed, the increase in the injection rates will not be favourable for shear

Total affected surface area

Shear stimulated surface area

HF Surface Area

(c)

(d)

(e)

**Figure 12.** Effect of elevated injection rates, history of quantitative indices.

Average HF Aperture

Average DFN Aperture

**•** Smaller injection rates result in a greater total affected surface area; and

(a)

(b)

stimulation.

284 Effective and Sustainable Hydraulic Fracturing

The response of pre-existing fracture networks, typically encountered in geothermal reservoirs and shale gas formations, to fluid injection, including potential HF propagation, has been studied numerically. This is the first in a proposed series of studies intended to obtain a better understanding of the complex processes involved in DFN stimulation and hydraulic fracturing by fluid injection.

The sensitivity of the models with respect to various in-situ and operational parameters has been evaluated. The results are summarized as follows:

### **Acknowledgements**

The authors acknowledge the financial support of Sandia National Laboratories for this project.


**1. Introduction**

Diabetes patients experience diabetic foot ulcer (DFU) as a result of prolonged hyperglycaemia, and it is the most common reason for hospitalisation. It is also associated with severe morbidity and mortality and, if not recognised and treated promptly, can result in limb amputation [1]. It also had an influence on the financial burden placed on patients, their families, society and the government for the treatment and management of DFU [2]. The risk of a patient with diabetes developing a foot ulcer has been estimated to be 19–34%, and the incidence rates for ulcer recurrence remain high which is 40% within 1 year after healing and 65% within 5 years [3].

Hyperglycaemia stimulates enzymes such as aldose reductase and sorbitol dehydrogenase, resulting in the conversion of intracellular glucose to sorbitol and fructose. The accumulation of these converted glucose products reduces the synthesis of myoinositol in nerve cells that are essential for energy production [4]. The chemical change caused by glucose also resulted in the depletion of nicotinamide adenine dinucleotide phosphate (NADP), which is required for the detoxification of reactive oxygen species (ROS) and the synthesis of the vasodilator, nitric oxide (NO). As a result, there is an increase in oxidative stress on nerve cells, as well as an increase in vasoconstriction on blood vessel, which leads to ischemia, which causes nerve cell damage and death [5]. The common sites for ulceration on foot are dorsal or plantar aspects of the toes, plantar metatarsal heads and heel.

There are numerous events in diabetic progress that can contribute to the development of DFU. The most important events are diabetic peripheral neuropathy (DPN), which affects half of all diabetics, peripheral vascular disease (PVD) and trauma and infection [6].

### **1.1 Diabetic peripheral neuropathy (DPN)**

DPN can be sensory, motor or autonomic. Sensory neuropathy reduces the patient's sensory awareness and manifests clinically as burning, tingling or paraesthesia in the stocking and glove distribution, which worsens after numbness symptoms appear [7]. The peripheral nerve fibres in diabetic patients are affected in a length-dependent manner, with the longest nerves being affected first, resulting in a stocking distribution of sensory loss. Sensory loss involving type A myelin fibres results in loss of proprioception, pressure sensation, vibratory perception and gait impairment. The destruction of type C sensory fibres results in an inability to recognise painful stimuli. As a result of these impaired sensations, the diabetic patient may suffer from repetitive foot trauma, such as blister formation or even metatarsal bone fracture, without realising it. Poor balance due to loss of proprioception, decreased sweating and dry skin that can develop skin cracks and fissures are all consequences of DPN [8].

Motor neuropathy can result in structural changes in the shape of the foot. It is typically presents as wasting of the intrinsic muscles of the foot, resulting in clawing of the toes and changes to the architecture of the mid-foot and subsequently in pressure redistribution over the metatarsal heads. Loss of the Achilles reflex is the earliest sign of these changes. With atrophy of the lumbricals and interosseous muscles, the anatomy of the foot arch changes, with a relative increase in extensor tendon forces producing a "claw" deformity of the toes. A shift to extrinsic muscle/tendon function contributes to depression of the metatarsal heads, hammer-toe contracture of the digits and equine ankle deformity [9].

Whereas autonomic neuropathy can impair the microvascular thermoregulation and anhidrosis process that adds to the motor and sensory disturbance. From this malfunction, the skin becomes dry as it loses the ability to moisturise its surface due to decreased secretory functions of the sebaceous and sweat glands and prone to fissuring, diminishes its effectiveness as a barrier to microorganism invasion, becoming susceptible to dermal infection, that is, cellulitis [10].


*4.1. Results for Growing and Shrinking Cities*

Based on the value of UDD and the categorization rules, 145 cities shrank during 2009–2018, accounting for 51.79%, mostly distributed in northeastern, central, and western China. A total of 135 cities grew, accounting for 48.21%, mostly distributed in the eastern coastal areas (Figure 2). Among the growing cities, 126 had slight growth, and 9 had rapid growth, accounting for 45% and 3.21%, respectively. Among the shrinking cities, 33 were rapidly shrinking, and 112 were slightly shrinking, accounting for 11.79% and 40%, respectively. Cities with slight growth account for the highest proportion, while those with rapid growth account for the lowest proportion. Most cities in China are SGCs or SSCs, while only a few are RGCs or RSCs.

**Figure 2.** Spatial distribution of shrinking and growing cities in China, 2009–2018.

4.1.1. Characteristics of Growing Cities

The UDD of RGCs exceeds 0.05; these include Nanjing, Hangzhou, Zhengzhou, Wuhan, Xi'an, Chongqing, Chengdu, Kunming, and Qingdao. Most of these cities are

provincial capitals with convenient transportation, good medical conditions, and high levels of education. Their economic development is at the highest level, with per capita GDPs of 50,000–110,000 yuan, and their economies are rapidly expanding. All of these RGCs have populations close to 10 million and are growing rapidly. Moreover, these cities have completed their industrial transformation and upgrading. In 2018, tertiary industry accounted for more than 55% of all industry in these cities (Figure 3a).

**Figure 3.** Industrial structure of growing and shrinking cities.

The UDD of SGCs ranges from 0 to 0.05; examples include Jinan, Suzhou, Ningbo, Jiaxing, Xiamen, and Fuzhou, mostly distributed in Shandong, Jiangsu, Zhejiang, and Fujian Provinces. Most of these cities are economically developed provincial capitals, with per capita GDPs of 40,000–80,000 yuan. Their economic development levels are lower than those of RGCs, but their economic growth is steady. Furthermore, the SGCs have established a leading position in tertiary industry by optimizing their industrial structures, with the proportion of tertiary industry accounting for more than 45% of the total (Figure 3b). This means that the service industry is constantly improving in these cities. Finally, their total populations show a trend of steady growth.

#### 4.1.2. Characteristics of Shrinking Cities

The UDD of RSCs is below −0.02. Examples include Anshan, Fushun, Zhangjiakou, Tangshan, Baotou, and Daqing, which are mostly distributed in Liaoning, Hebei, and Inner Mongolia. Most of these cities are resource based, mainly relying on mineral resources during their early stage of development, with secondary industry accounting for more than 50% of the total (Figure 3c). Adjustments to the industrial structure started late in these cities. Their economic development is below the middle level, with per capita GDPs mostly between 30,000 and 60,000 yuan. RSCs are experiencing economic decline and population loss.

The UDD of SSCs is between −0.02 and 0. This includes Yichun, Liaoyuan, Datong, Kaifeng, Zigong, and other cities, mostly distributed in Heilongjiang, Jilin, Shanxi, Henan, Gansu, and Sichuan Provinces. Compared with RSCs, SSCs are mostly resource-based cities, taking secondary industry as the leading industry. After industrial restructuring, however, secondary industry accounted for less than 50%, while the service industry accounted for nearly 45% (Figure 3d). In addition, these cities are far away from economically developed cities, have poor geographical location conditions and transportation accessibility, and have relatively low levels of economic development. Their per capita GDP is 20,000–50,000 yuan. Their economies are growing but their populations are diminishing.

#### *4.2. Emission Characteristics of Growing and Shrinking Cities*

The carbon emissions of RGCs show a trend of fluctuating growth, RSCs present an inverted U-shaped trend, and SGCs and SSCs rise first and then develop steadily (Figure 4). The carbon-emission trends of the four groups are different, and their driving factors may be different as well. Here, we analyze the possible effects of economies, industrial structure, and technology on the carbon-emission characteristics of the four city groups.

**Figure 4.** CO2 emission characteristics of growing and shrinking cities.

#### 4.2.1. Rapidly Growing Cities (RGCs)

The carbon emissions of RGCs are the highest among the four groups, with a trend of fluctuating growth (Figure 4a). From 2009 to 2012, carbon emissions grew at an annual rate of 3.3%. They fluctuated from 2013 to 2016 and continued to grow at an average annual rate of 2.4% in 2017 and 2018. In terms of economic growth, the GDP of RGCs shows an increase of 298.9%, with primary, secondary, and tertiary industries increasing by 202.9%, 247.6%, and 361.7%, respectively. This indicates rapid economic expansion, which contributes to increases in emissions. Between 2013 and 2016, however, the growth rate of GDP slowed down (annual GDP growth during this period was around 10%, lower than in other periods) (Figure 5a), which slowed the growth of carbon emissions over the period. In terms of

industrial structure, the proportion of primary and secondary industry continues to decline, while the proportion of tertiary industry continues to rise. The service industry in RGCs is relatively mature and has occupied a dominant position for a long time, making increasing contributions to the economy. Therefore, the development of services may contribute to the increase in carbon emissions. In terms of energy structure, the proportion of coal in RGCs generally shows a downward trend, especially during 2012–2015. The proportion of coal shows a rapid decline (Figure 6), which may help to reduce carbon emissions. In terms of technology, energy intensity drops from 0.74 to less than 0.26 (tec/104 yuan), an annual decrease of about 11%, showing a rapid downward trend (Figure 7). This means that technology was greatly improved during the study period. We can see that the energy structure and technology of RGCs have been optimized and improved, which helps reduce carbon emissions. However, the carbon-increasing effect of rapid economic expansion and expanded tertiary industry is greater than the carbon-reducing effect of energy structure optimization and technological progress. Therefore, overall urban carbon emissions show an increasing trend.

**Figure 5.** GDP and GDP growth rate of the four city groups.

#### 4.2.2. Slightly Growing Cities (SGCs)

The carbon emissions of SGCs are low among the four city groups, showing a trend of first rising and then changing only slightly (Figure 4b). Specifically, from 2009 to 2012, the carbon emissions of SGCs increased from 24.83 million tons to 30.18 million tons, with an annual growth rate of 5%. Between 2013 and 2018, emissions were around 30 million tons, a small change. In economic terms, the economies of SGCs show an increase of 258.2%. However, GDP growth generally shows a downward trend after 2012 (Figure 5b). Although economic expansion may increase carbon emissions, a decline in economic growth might also slow down the growth of emissions, accounting for the slowed growth of emissions after 2012. In terms of industrial structure, the proportion of primary and secondary industry continues to decline, while that of tertiary industry keeps rising. Especially after 2012, the proportion of secondary industry dropped rapidly (annual decline of 2%). This

means that the cities reduced their dependence on energy-intensive industries, which helps reduce carbon emissions. In terms of energy structure, the proportion of coal in SGCs is 62%–66%, and there is a small decline (Figure 6). The urban energy structure has been optimized, and the decline in the proportion of coal is conducive to reducing carbon emissions. In terms of technology, the energy intensity of SGCs decreases year by year, from 0.7 in 2009 to 0.34 (tec/104 yuan) in 2018, an annual decrease of 7.6% (Figure 7). This could be another reason for the slowed growth of carbon emissions. In general, economic expansion in the SGCs increased carbon emissions. After 2012, however, with slowed economic growth, accelerated changes in industrial structure, energy structure optimization, and technological progress, the growth of carbon emissions was restrained, stabilizing changes in emissions.

**Figure 6.** Coal share of growing and shrinking cities.

**Figure 7.** Energy intensity of growing and shrinking cities.

#### 4.2.3. Rapidly Shrinking Cities (RSCs)

Among the four city groups, RSCs' carbon emissions are high, presenting an inverted U-shaped trend; 2013 is a turning-point year (Figure 4c). Regarding the economy, despite RSC economies showing growth, their GDP growth rate first rises and then declines rapidly, indicating that their economies declined after a period of growth (Figure 5c). This is consistent with the change characteristics of carbon emissions. We can infer, therefore, that

economic changes triggered the changes in emissions. In terms of industrial structure, the proportion of secondary industry increases first and then decreases, while tertiary industry shows the opposite trend. This means that the cities gradually reduced their dependence on secondary industry and developed tertiary industry, which could curb carbon emission growth. In terms of energy structure, the overall change in coal consumption is relatively small (Figure 6), which differs greatly from the change in carbon emissions. Therefore, energy structure might not have an effect on carbon emissions. Meanwhile, the energy intensity of RSCs decreases from 0.88 to 0.42 (tec/104 yuan) (Figure 7); technology was improved, which is conducive to reducing carbon emissions. This analysis reveals that economic and industrial structure (secondary industry) and carbon emissions show the same change characteristics; thus, they may be the main reasons for changes in emissions. Although technological progress can restrain carbon emissions, emissions still show an increasing trend in the early stage. Therefore, technological progress had a weak effect on reducing emissions in the early part of the study period but might account for the reduced emissions in the latter part.

#### 4.2.4. Slightly Shrinking Cities (SSCs)

SSCs have the lowest total carbon emissions among the four city groups. Their carbonemission trend is similar to that of SGCs, showing a trend of first rising and then changing only a little (Figure 4d). Specifically, carbon emissions rose from 15.14 million tons to 18.09 million tons from 2009 to 2012 and then remained around 18 million tons. In terms of economic development, the GDP of SSCs expanded overall, but the GDP growth rate declined year by year, especially after 2012 (Figure 5d). In terms of industrial structure, the change characteristics for SSCs are similar to those of RSCs, with the proportion of secondary industry first rising and then falling and that of tertiary industry first falling and then rising. Specifically, the proportion of secondary industry rose from 49.3% in 2009 to 51.16% in 2013, and then dropped to 42.18% in 2018. The proportion of tertiary industry fell from 34.5% to 32.8% and then rose to 44.6%. The expansion of economic scale increased carbon emissions, but the slowdown of economic growth and the adjustment of industrial structure after 2012 helped to curb emissions, making them relatively stable. In terms of energy structure, the proportion of coal in SSCs increased from 62.9% in 2009 to 65.8% in 2018 (Figure 6); this means that the energy structure did not improve. Therefore, the energy structure might not be the reason for reduced carbon-emission growth. The energy intensity of SSCs declined annually by 5.4% (Figure 7). The development of low-carbon technologies might be the reason for the reduced growth of emissions.

#### *4.3. Regression Results*

According to the F-test and Hausman test results, for SGCs, RSCs and SSCs, the fixedeffects model should be used for regression, while the mixed-effects model should be used for RGCs, as shown in Table 2. However, by comparing the mixed-effects regression results with the fixed-effects regression results, the significance of the coefficients of influencing factors has not changed a lot. Therefore, in order to be comparable with the regression results for the other three groups of cities, a fixed-effects model was used for RGCs.

**Table 2.** F-test and Hausman test for four city groups.

Table 3 shows the estimation results of the fixed-effects model for four city groups. It can be found that the regression results of the models in SGCs, RSCs and SSCs perform better, showing that the R-squared values are more significant. The regression result for RGCs is relatively insignificant, mainly due to the small samples, which makes its explanatory power limited. However, the regression result for RGCs is similar to SGCs, mainly because they belong to growing cities, so the results are reasonable to a certain extent.

**Table 3.** Regression results.

Note: \*\*\* *p* < 0.01, \* *p* < 0.1.

Based on the regression results, population and economic growth have a positive effect on carbon emissions, while technological progress has a negative effect on carbon emissions. The proportion of tertiary industry has a positive impact on growing cities, but has a negative impact on shrinking cities. For RGCs, the proportion of tertiary industry has the largest and most significant impact on emissions, which means that the proportion of tertiary industry is the primary influencing factor for carbon emissions in RGCs. An increase of 1% in the proportion of tertiary industry increases carbon emissions by 1.337%. For SGCs and RSCs, population is the most important factor affecting carbon emissions, showing that carbon emissions increase by 0.943% and 0.722% for every 1% increase in population. The technological progress has the greatest negative impact on SGCs, RSCs and SSCs. For every 1% increase in technological level, carbon emissions decrease by 0.709%, 0.518% and 0.547%. For SSCs, the economic growth has the largest positive impact, as every 1% increase in the economy increases carbon emissions by 0.74%.

In order to further verify the robustness of the regression results, we run a Stochastic Frontier Analysis (SFA) model on the extended STIRPAT, and the SFA results are in high agreement with the regression results, indicating our result is robust. Moreover, referring to Wang et al. [21], we compare the fitting data of CO2 emission (lnCO2) calculated by the regressions coefficients in Table 3 with the actual CO2 emissions (lnCO2). The margin of error is within 10%, and most are less than 5%, as shown in Table 4, indicating that the regression model is available.


*3.2. Antioxidant Activity*

Both in the DPPH and ABTS assays, imidazole presented EC50 of >15 and >10 mg/mL, respectively (Table 1), which compared to most of the results shown by its derivatives, suggests that the 2,4,5-triphenyl substitution in the imidazole heterocyclic is relevant for the antioxidant activity of these compounds, where the e ffect of their substitutions on their A ring is further developed below.

The DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging method is widely used to evaluate antioxidant activities in a relatively short period of time compared to other methods. The results of this assay are shown in Table 1, comparing the synthesized products with the standard quercetin, where the most active synthesized imidazole derivatives were **3**, **10**, **7**, and **2** with values of EC50 of 0.141, 0.174, 0.341, and 1.389 mg/mL, respectively. These results show that the presence of electron donating groups such as hydroxy and *p*-dimethylamino on an aromatic ring bonded to imidazole are essential in the antioxidant activity. The consulted literature indicates that this could be due to the free pair of electrons in nitrogen or in the oxygen of the hydroxy group, which can react with free radicals, being favored due to their aromatic ring stabilization [29]. The rest of the compounds presented low activity in this assay, mainly because of their lack of acidic hydrogen in the aromatic system of position two (A ring); instead, compounds **4**, **5**, **6** and **8** bear methoxy groups, there is a chlorine atom in **9** (EC50 of 5.62 mg/mL), an electron attractor e ffect of the NO2 group in products **11** and **12**, and an anthracene group in **13**.

It is interesting to point out the di fference in antioxidant activity between isomers **2** and **3**, where it is shown from the last one that there was a higher oxidative inhibitory potential in both employed techniques (DPPH and ABTS). It is well known that the antioxidant mechanisms of phenolic compounds are hydrogen atom transfer and single electron transfer, in order to inhibit free radicals, which are the expected mechanisms for the phenolic hydroxyls present in these isomers. These di fferent results could be due to the fact that even though both compounds can transfer their hydrogens because of their high acidity, hydroxyl in **2** is in an *ortho* position, favoring the formation of a hydrogen bond along with a nitrogen of the imidazole nucleus, and forming a 6-membered stable ring. It is referenced that these hydrogen bond interactions can diminish the hydrogen dissociation and therefore the antioxidant ability of these groups [30].

In 2015, Hemalatha et al. [31] evaluated the antioxidant activity with a DPPH assay of compounds **2**, **3**, and **10**, reporting IC50 values of 0.003, 0.0037, and 0.0031 mg/mL, respectively, while the IC50 values for the same compounds in our analysis were 1.389, 0.141 and 0.174 mg/mL, respectively. Even though there were notorious di fferences between both results, establishing a direct comparation was complicated due to di fferences in the methodologies employed for the assay, as in [31], a higher concentration of the DPPH radical was employed, and the incubation times for the reactions were not stated.

In a similar way to the DPPH methodology, the ABTS radical-scavenging assay showed that compounds **10**, **3**, **2**, and **7** with EC50 values of 0.162, 0.168, 0.188 and 0.199 mg/mL, respectively, were the most active products, however, compound **13** showed moderate activity, while products **1**, **4**, **5**, **6**, **8**, **11**, and **12** presented low activity, as can be seen in Table 1. With these compounds, once again, it is important to emphasize that the participation of hydroxyl and dimethylamino groups play an important role as free radical scavengers. Several reports have discussed the possible mechanisms involved in ABTS+ quenching, suggesting the mixed hydrogen atom transfer/single electron transfer reaction mechanisms [32], and some groups have these properties of chemical reactivity such as *N*,*N*-dimethylaniline derivatives, which can generate e fficient and stable radicals [33].


**7.4 Use of botulinum toxin a in the of overactive bladder**

Patients who has refractory overactive bladder symptoms are over by clinicians Botulinum toxin A by the clinician and at this stage the patient case would have have had urodynamic studies that confirms detrusor overactivity and have her case discussed in the multidisciplinary team meeting that include urogynaecologist, urogynaecoogology nurse Specilaist, phythiotherapist and may include also a urologist [19].

Botulinum toxin A is an extremely potent neurotoxin and its Intravesical injection under local or general anaesthesia via cystoscopy improves the over active bladder symptoms up to 90%. The most commonly applied regimen is use of 100 units of botox in 20 injection points through the bladder sparing the trigone area. The effect of botox injection wears off in 3–12 months depends on the severity of overactive bladder symptoms. Approximately 5–10% of patients receiving botox injection can develop urine retention postoperatively and hence preoperative teaching of the patient how to self catheterise and empty the bladder twice a day is very important [20–22].

The role of urogynaecology nurse at this stage is participating in patient education about about the botox benefits and help the patient to obtain the relevant information leaflets. Also, nurse specialist should be able to teach the patient self catheterisation and ensure it is done promptly especially in old patients with joint movement or rheumatoid arthritis difficulty who has difficulty in reaching out to able to self catheterise. In tertiary units with cavities of training and supervision urogynaecology nurses can perform outpatient cystoscopic botox injection.


*Sedation:*

*Special Considerations in Human Airway Management*

○ Avoid the stress of direct laryngoscopy.

○ Direct visualization of the vocal cords.

○ Maximum incidence of success.

○ Maximum safety in awake patients.

○ Definitive control of the ET position.

○ Endoscopic study before intubation.

○ Possibility of oral or nasal application.

with the patient awake to avoid unnecessary risks.

report not so high odds of success with DA patients [21].

checklist of all the supplies needed should be disposable.

○ Minimal risk of injury.

haemodynamic response.

○ Short intubation time according to training.

○ Less traumatic and less repeated intubation attempts.

○ Possibility of execution in extreme positions [31–33].

the "gold standard" in the treatment of "predicted difficult airway."

○ Allows the administration of oxygen through the suction channel.

Due to all these advantages, intubation with FBO is the cornerstone of DA management as well as its ultimate goal: suspect and identify a DA, perform intubation

Intubation with an awake patient while maintaining spontaneous breathing is

Awake fiber-optic intubation is reported to be successful in 88–100% of DA patients. Case reports using other techniques for awake intubation (blind tracheal intubation, intubation through supraglottic devices, optically guided intubation)

Awake intubation has the following advantages [28, 34]: the patient retains the ability to keep the ventilation and airway patent and the muscle tone that keeps the pharynx clean and preserved; the collaboration of the patient and helps us pass the ET with deep breathing; with good local anesthesia, it facilitates a poor

FBOs also have disadvantages [33]: necessary training, skill, patient cooperation, longer execution time, optical fibers are fragile and require rigorous precautions. The route for tracheal intubation should take into account the patient's anatomy, surgical access, and the tracheal extubation plan. In patients with limited mouth opening, the nasal approach is the only option, while in patients who had nasal surgical interventions, the oral approach should be preferred. No evidence or consensus is found among experts on the superiority of a route if both are feasible. Awake tracheal intubation (ATI) by using video-laryngoscopy has the same success rate and safety as ATI: FBO (98.3% each) [35]. Careful selection of the tracheal tube is critical to the success of any ATI technique. It is advisable to use the tracheal tube with a smaller external diameter, as it can reduce the incidence of injury [36]. A

*Oxygenation*: Desaturation (SpO2 ≤ 90%) with low-flow (< 30 l/min-1) oxygen techniques during ATI ranges between 12% and 16% [37, 38]. When using warmed and humidified high-flow nasal oxygen, desaturation plummets to 0–1.5% [39]. Administration of supplemental oxygen during ATI is highly recommended. It should

*<IP_ADDRESS> Advantages of FBO-guided intubation*

**294**

ATI may be safe and effective even performed in the absence of sedation [42, 43]. Its use during ATI can reduce patient anxiety and discomfort and increase procedural tolerance. In certain patient populations, the risk of over-sedation is particularly hazardous, thus an independent practitioner delivering sedation is strongly recommended. Based on our experience, we can recommend the use of minimal sedation. Two drugs, remifentanil and dexmedetomidine have been associated with high levels of patient satisfaction and low risk of over-sedation and airway obstruction. Complications are reduced when using capnography.

#### *<IP_ADDRESS> Indications and contraindications for FBO-guided intubation*

#### *<IP_ADDRESS> Contraindications to FBO-guided intubation*

	- Hypoxemia.
	- Laryngospasm and bronchospasm.
	- Haemodynamic disorders and arrhythmias.
	- Esophageal intubation.
	- Sore throat.
	- Tissue trauma.
	- Regurgitation or vomiting. Aspiration.
	- Stridor or oedema of the glottis.
	- Esophageal perforation.
	- Gastric distension. Rupture of the stomach.
	- Bleeding, epistaxis.
	- Eye trauma.
	- Pulmonary barotrauma.
	- Arrhythmias: bradycardia due to nasal stimulation (naso-cardial reflex) or stimulation of the region of the recurrent and superior laryngeal nerve.
	- Haemodynamic disorders: hypertension or hypotension is justified by a diminished stimulus.
	- Barotrauma: in the narrow upper respiratory tract.
	- Esophageal intubation.
	- Regurgitation and vomiting.
	- Gastric distension: stomach rupture [45].