**7.3 Obstetric population**

Mendelson was the first to describe 66 cases of aspiration between 1932 and 1945, with an incidence of 1 in 667 parturient and two deaths, both caused by acute upper airway obstruction. The mortality incidence was estimated about 1 in 22,008 [48]. In ASA closed claims, obstetric related aspiration constituted a 21% of all claims. A dramatic decreasing trend over time, in the 1970–1979; 43% of the respiratory claims compared to 20% in the 1980s and only 7% (two claims) of the aspiration claims in the 1990s. This suggests that benefit of the aspiration prevention strategies in the obstetric populations that introduced into clinical practice in the 1980s. A recent literature review found an incidence of failed tracheal intubation of 2.6 per 1000 obstetric general anesthesia (1 in 390) and associated maternal mortality of 2.3 per 100,000 general anesthesia (one death for every 90 failed intubations) [49].

The main recommendation is to adopt the neuraxial blocks as a main anesthetic technique, optimum pharmacological prophylaxis, avoiding of general anesthesia, minimizing airway manipulation and relying on RSII if general anesthesia cannot be avoided [50].

#### **7.4 Trauma and other life saving/organ saving surgeries**

Trauma and life-saving procedures have been proved to delay gastric emptying; thus, the fasting time may not be reliable. The volume of the gastric content is related to the nature of the trauma/emergency event, the interval between the last food intake and the time of acute event. Ultrasound studies have demonstrated that 56% of adult emergency cases have full stomach even though they were fasting (median 18 h). A patient for emergency surgery should always be considered as having a full stomach, thus adequate precautionary measures must be assumed to prevent aspiration. In trauma or other emergency events, prokinetics are not recommended. Erythromycin might facilitate gastric emptying in such patients but with a limited available evidence. Preoperative insertion of nasogastric tube is recommended only in cases of acute bowel obstruction but may not ensure adequate gastric emptying and could be associated with complications. Rapid sequence induction and intubation with cricoid pressure must be practiced in such cases in order to prevent aspiration [51].

#### **7.5 Airway management for patient with NG tube in situ**

Routine preoperative nasogastric tube (NG) insertion is not recommended except in selected patient with small bowel or gastric outlet obstruction. Usually those patients present to operating theater with nasogastric tube placed preoperatively. Whether to keep the gastric tube in situ, withdraw it to the esophagus, or remove it completely before induction of anesthesia is a debatable issue. The presence of the gastric tube may diminish the function of the upper and lower esophagus sphincter, with no impairment of the efficacy of cricoid pressure during rapid sequence induction based on cadaveric studies [33]. Enteral feeding usually contains carbohydrates, fat and protein, so it is considered as a full meal, thus should be stopped 8 h prior to surgery in patient that do not have endotracheal tube or tracheostomy tube in place and to continue tube feeding in case post pyloric position of the feeding tube for non-abdominal surgery [52]. As prolonged nutritional restriction may result in catabolic state in severely ill patient, however, continuation of enteral feeding might lead to aspiration, the decision to continue enteral feeding or stop it is a case-based decision with assistance of multidisciplinary team of anesthesiologist, surgeon and the primary physician. In conclusion, the current consensus is that a gastric tube, after stomach is decompressed, should not be withdrawn and left in situ during rapid sequence induction based on available literatures [27].

#### **7.6 Airway management in post-bariatric surgery patient**

Currently, the laparoscopic gastric banding and the laparoscopic Roux-en-Y gastric bypass are the most performed bariatric procedures that have proven safe, cost effective with fewer complications [53]. The major changes in gastric anatomy and physiology after weight reduction surgeries are decrease in esophageal sphincter relaxation and change in esophageal-gastric peristalsis, thus there is potential risk of esophageal regurgitation and pulmonary aspiration during general anesthesia [54]. Despite dramatic weight loss, the risk of perioperative pulmonary aspiration in post bariatric surgery patient was 6% [55]. Therefore, Post-bariatric patients must be carefully evaluated preoperatively with attention to signs and symptoms of reflux/regurgitation and delayed gastric emptying. Currently, there are no guidelines on airway and anesthetic management for post-bariatric patients. However, such patients should be encouraged to consume only liquid meals the day before the operation, prolonged pre-operative fasting period maybe helpful in the

**119**

*Airway Management in Full Stomach Conditions DOI: http://dx.doi.org/10.5772/intechopen.93591*

**7.7 Upper airway bleeding**

management in these patients [57].

matic airway manipulation.

for airway management.

a maximum of three [58].

a cuffed tube [57].

an awake intubation should be the technique of choice [56].

to address the source of bleeding and controlling it [57].

preoperative period. Intraoperatively, Rapid-sequence induction and intubation (RSII) with definitive airway as the anesthetic technique of choice and insertion of nasogastric tube must be considered. In patients with an expected difficult airway,

Upper airway bleeding is a catastrophic event that might cause airway related death even in healthy young patients. Airway management in those patients is extremely challenging. Some of techniques used to secure airway such as video laryngoscope or fiberoptic laryngoscopes might be ineffective because of the soiled hypopharynx and equipment with blood, effective preoxygenation might be difficult in an anxious not tolerated patient, THRIVE and HFNO should be used with extreme caution because blood may force in lower airway, use of SAD has limited effectiveness because of the high risk of aspiration, patient swallow the blood and should be considered as a full stomach case and patient cannot lie supine feeling suffocated and difficult to deal with, are the main problems associated with airway

Upper airway bleeding might be idiopathic such as nasal bleeding, bleeding tumor and vascular malformation, trauma to face and neck, post-surgery for instance post tonsillectomy bleeding or cancer surgery or iatrogenic such as trau-

Airway management started with airway examination and localizing cricothyroid membrane as an emergency solution of cannot intubate scenario. Out of all the airway management ways, only the placement cuffed ETT using RSII might fulfill the desired goals which are; securing a conduit for patient ventilation, protect the patient from blood aspiration in the lungs, and provide good space for the surgeon

In case of failure to intubate the patient, SAD devices, retrograde intubation or blind nasal intubation in case of spontaneous breathing patient could be a solution

Failure of the above techniques mandate cricothyroidotomy or tracheotomy with

**7.8 Rapid sequence induction and intubation (RSII) for COVID19 patients**

There is a high chance of aerosol spread of the virus during airway management of patient with COVID 19. RSII is the preferred way to intubate those patients. Awake intubation should not be done because coughing during intubation increase virus spread. All standard airway equipment should be available plus bag mask with High Efficiency Particular Air filter (HEPA) filter, video laryngoscope with disposable blades, ventilator and tubing with inline adapter and HEPA filter and smooth clamp for ETT. It is preferred to intubate the patient in negative pressure room if available and to limit staff available during intubation to

After strict donning process with full Personal Protective Equipment (PPE), preoxygenate the patient for 3–5 min using 10–15 l/min of 100% O2 and avoid bag mask ventilation (BMV) if possible. If saturation drops and BMV is needed so assure tight mask fitting with no leaks. Use of high dose of muscle relaxant Rocuronium or Suxamethonium to avoid coughing while intubation, use video laryngoscope if it is available, inflate ETT cuff as soon as possible, clamp the ETT before connecting to ventilator, HEPA filter should be placed between the ETT and

the ventilator [59] (for more details, kindly refer to Chapter 1).

preoperative period. Intraoperatively, Rapid-sequence induction and intubation (RSII) with definitive airway as the anesthetic technique of choice and insertion of nasogastric tube must be considered. In patients with an expected difficult airway, an awake intubation should be the technique of choice [56].

## **7.7 Upper airway bleeding**

*Special Considerations in Human Airway Management*

order to prevent aspiration [51].

**7.4 Trauma and other life saving/organ saving surgeries**

**7.5 Airway management for patient with NG tube in situ**

**7.6 Airway management in post-bariatric surgery patient**

Trauma and life-saving procedures have been proved to delay gastric emptying; thus, the fasting time may not be reliable. The volume of the gastric content is related to the nature of the trauma/emergency event, the interval between the last food intake and the time of acute event. Ultrasound studies have demonstrated that 56% of adult emergency cases have full stomach even though they were fasting (median 18 h). A patient for emergency surgery should always be considered as having a full stomach, thus adequate precautionary measures must be assumed to prevent aspiration. In trauma or other emergency events, prokinetics are not recommended. Erythromycin might facilitate gastric emptying in such patients but with a limited available evidence. Preoperative insertion of nasogastric tube is recommended only in cases of acute bowel obstruction but may not ensure adequate gastric emptying and could be associated with complications. Rapid sequence induction and intubation with cricoid pressure must be practiced in such cases in

Routine preoperative nasogastric tube (NG) insertion is not recommended except in selected patient with small bowel or gastric outlet obstruction. Usually those patients present to operating theater with nasogastric tube placed preoperatively. Whether to keep the gastric tube in situ, withdraw it to the esophagus, or remove it completely before induction of anesthesia is a debatable issue. The presence of the gastric tube may diminish the function of the upper and lower esophagus sphincter, with no impairment of the efficacy of cricoid pressure during rapid sequence induction based on cadaveric studies [33]. Enteral feeding usually contains carbohydrates, fat and protein, so it is considered as a full meal, thus should be stopped 8 h prior to surgery in patient that do not have endotracheal tube or tracheostomy tube in place and to continue tube feeding in case post pyloric position of the feeding tube for non-abdominal surgery [52]. As prolonged nutritional restriction may result in catabolic state in severely ill patient, however, continuation of enteral feeding might lead to aspiration, the decision to continue enteral feeding or stop it is a case-based decision with assistance of multidisciplinary team of anesthesiologist, surgeon and the primary physician. In conclusion, the current consensus is that a gastric tube, after stomach is decompressed, should not be withdrawn and left in situ during rapid sequence induction based on available literatures [27].

Currently, the laparoscopic gastric banding and the laparoscopic Roux-en-Y gastric bypass are the most performed bariatric procedures that have proven safe, cost effective with fewer complications [53]. The major changes in gastric anatomy and physiology after weight reduction surgeries are decrease in esophageal sphincter relaxation and change in esophageal-gastric peristalsis, thus there is potential risk of esophageal regurgitation and pulmonary aspiration during general anesthesia [54]. Despite dramatic weight loss, the risk of perioperative pulmonary aspiration in post bariatric surgery patient was 6% [55]. Therefore, Post-bariatric patients must be carefully evaluated preoperatively with attention to signs and symptoms of reflux/regurgitation and delayed gastric emptying. Currently, there are no guidelines on airway and anesthetic management for post-bariatric patients. However, such patients should be encouraged to consume only liquid meals the day before the operation, prolonged pre-operative fasting period maybe helpful in the

**118**

Upper airway bleeding is a catastrophic event that might cause airway related death even in healthy young patients. Airway management in those patients is extremely challenging. Some of techniques used to secure airway such as video laryngoscope or fiberoptic laryngoscopes might be ineffective because of the soiled hypopharynx and equipment with blood, effective preoxygenation might be difficult in an anxious not tolerated patient, THRIVE and HFNO should be used with extreme caution because blood may force in lower airway, use of SAD has limited effectiveness because of the high risk of aspiration, patient swallow the blood and should be considered as a full stomach case and patient cannot lie supine feeling suffocated and difficult to deal with, are the main problems associated with airway management in these patients [57].

Upper airway bleeding might be idiopathic such as nasal bleeding, bleeding tumor and vascular malformation, trauma to face and neck, post-surgery for instance post tonsillectomy bleeding or cancer surgery or iatrogenic such as traumatic airway manipulation.

Airway management started with airway examination and localizing cricothyroid membrane as an emergency solution of cannot intubate scenario. Out of all the airway management ways, only the placement cuffed ETT using RSII might fulfill the desired goals which are; securing a conduit for patient ventilation, protect the patient from blood aspiration in the lungs, and provide good space for the surgeon to address the source of bleeding and controlling it [57].

In case of failure to intubate the patient, SAD devices, retrograde intubation or blind nasal intubation in case of spontaneous breathing patient could be a solution for airway management.

Failure of the above techniques mandate cricothyroidotomy or tracheotomy with a cuffed tube [57].

#### **7.8 Rapid sequence induction and intubation (RSII) for COVID19 patients**

There is a high chance of aerosol spread of the virus during airway management of patient with COVID 19. RSII is the preferred way to intubate those patients. Awake intubation should not be done because coughing during intubation increase virus spread. All standard airway equipment should be available plus bag mask with High Efficiency Particular Air filter (HEPA) filter, video laryngoscope with disposable blades, ventilator and tubing with inline adapter and HEPA filter and smooth clamp for ETT. It is preferred to intubate the patient in negative pressure room if available and to limit staff available during intubation to a maximum of three [58].

After strict donning process with full Personal Protective Equipment (PPE), preoxygenate the patient for 3–5 min using 10–15 l/min of 100% O2 and avoid bag mask ventilation (BMV) if possible. If saturation drops and BMV is needed so assure tight mask fitting with no leaks. Use of high dose of muscle relaxant Rocuronium or Suxamethonium to avoid coughing while intubation, use video laryngoscope if it is available, inflate ETT cuff as soon as possible, clamp the ETT before connecting to ventilator, HEPA filter should be placed between the ETT and the ventilator [59] (for more details, kindly refer to Chapter 1).
