Is it possible to aspirate while intubated

Arch Phys Med Rehabil ; Aspiration and relative risk of medical complications following stroke. Arch Neurol ; Detection failure rate of chest radiography for the identification of nursing and healthcare-associated pneumonia.

J Infect Chemother ; Quantitative aspiration during sleep in normal subjects. Chest ; Is penicillin G an adequate initial treatment for aspiration pneumonia? Intensive Care Med ; Marik PE, Careau P. The role of anaerobes in patients with ventilator-associated pneumonia and aspiration pneumonia: A prospective study. The occurrence of aspiration pneumonia after emergency endotracheal intubation. Am J Emerg Med ; A pilot randomized clinical trial assessing the effect of cricoid pressure on risk of aspiration.

Clin Respir J ; Fever, cough, and bilateral lung infiltrates. Achalasia associated with aspiration pneumonia.

Oropharyngeal dysphagia is a risk factor for community-acquired pneumonia in the elderly. Eur Respir J ; Takenaka I, Aoyama K. Prevention of aspiration of gastric contents during attempt in tracheal intubation in the semi-lateral and lateral positions. World J Emerg Med ; Elpern EH. Pulmonary aspiration in hospitalized adults. Nutr Clin Pract ; Pharyngeal aspiration in normal adults and patients with depressed consciousness.

Anesthesia and Analgesia. Abstract-Europe PMC. Aspiration of gastric contents: Association with prehospital intubation. Airway management in the emergency department: A one-year study of tracheal intubations.

Rapid sequence intubation in the emergency department: 5 Year trends. The effectiveness of rapid sequence intubation RSI versus non-RSI in emergency department: An analysis of multicenter prospective observational study. Int J Emerg Med ; Aerosol generating procedures and risk of transmission of acute respiratory infections to healthcare workers: A systematic review. PLoS One ;7:e The aerosol box for intubation in coronavirus disease patients: An in-situ simulation crossover study.

Anaesthesia ; Comparison of aerosol box intubation with C-MAC video laryngoscope and direct laryngoscopy — A randomised controlled trial. Indian J Anaesth ; The UOS acts to prevent the reflux of oesophageal contents into the pharynx in conscious individuals. UOS tone is reduced in patients with reduced consciousness and attenuated by most drugs used for the induction and maintenance of anaesthesia with the notable exception of ketamine. Both depolarizing and non-depolarizing neuromuscular blocking agents reduce UOS tone, and some evidence suggests that residual neuromuscular block significantly reduces UOS tone for a significant time after emergence, increasing the risks of aspiration during the recovery phase.

Protective upper airway reflexes include coughing, expiration and laryngospasm. These protective reflexes are variably affected by reduced levels of consciousness and may be reduced at any stage of the perioperative period, including after emergence. Elderly patients are particularly prone to higher risks of aspiration under anaesthesia because they, in general, have less active airway reflexes. The vast majority of anaesthetic techniques attenuate the protective physiological mechanisms that prevent regurgitation and aspiration.

Inadequate depth of anaesthesia or unexpected responses to surgical stimulation may evoke gastrointestinal motor responses, such as gagging or recurrent swallowing, increasing gastric pressure over and above LOS pressure facilitating reflux.

An unprotected airway, excessively light depths of anaesthesia, and one or more predisposing risk factors for aspiration combine to significantly increase the risks of aspiration. NAP4 2 highlighted that poor judgement was the likely root cause in many cases of aspiration. Poor assessment of patient and operative risks, and failure to use airway devices or techniques offering greater protection against aspiration were common themes. The predisposing risk factors for aspiration can be classified by patient factors, operative factors, anaesthetic factors, or device factors shown in Box 1.

There is a variation in the effect of individual risk factors on overall aspiration risk, but gastrointestinal pathology and pregnancy both markedly increase aspiration risk. These effects are compounded in emergency surgery and if the lithotomy position is used. In pregnancy, the gravid uterus displaces the stomach, so altering the angle formed between the oesophagus and stomach. This effect is exacerbated by maternal obesity, multiple pregnancy, and polyhydramnious.

Higher concentrations of progesterone reduce barrier pressure further by relaxing the LOS, whilst decreased concentrations of the peptide hormone motilin delays gastric emptying. Aspirated blood is most commonly associated with intra-oral surgery or tonsillectomy. Aspirated blood may clot, causing total airway obstruction and death if not recognized promptly.

NAP4 2 documented two deaths caused by the aspiration of blood after extubation, one after dental surgery and the other in a child after routine tonsillectomy.

Ventilation after re-intubation was only possible after sizeable blood clots were aspirated from the trachea. Inadequate use of capnography contributed to deaths in both cases. In one of the cases, there was no evidence of its use after re-intubation, and in the other a flat capnograph trace, indicating failure of ventilation, was misinterpreted.

The multiple strategies available to anaesthetists to reduce the risk of aspiration are summarized in Table 1. Guidelines to reduce the risk of aspiration 7. The guidelines recommended anaesthetists to extubate all patients on their sides.

However, contrary to this advice, a survey of anaesthetic practice noted the emerging trend to manage extubation in the head-up or sitting position. Worryingly, evidence suggests that even when the risk of regurgitation is high enough to indicate rapid sequence induction, the same logic is not applied to extubation, when the risk of regurgitation is unlikely to have diminished. The tendency to view aspiration risk as only relevant at induction contradicts evidence that aspiration also occurs during maintenance 13 of 23 cases in NAP4 2 and during emergence 1 in 23 cases in NAP4.

The guidelines Table 1 are contentious given the recommendation to use cricoid pressure whenever neuromuscular blocking agents are used. Cricoid pressure can increase the frequency of difficult intubation, especially if excessive force is used, and the evidence base does not robustly support its effectiveness in reducing regurgitation. So, whilst the universal use of cricoid pressure may reduce regurgitation, the recommendation needs to be balanced by the likelihood that it would increase problems with intubation.

If aspiration occurs, management is directed to supportive treatment and organ support. Anaesthetists should have a low index of suspicion and recognize aspiration should it occur. The trachea should be suctioned once the airway is secure, ideally before positive pressure ventilation to prevent the distal displacement of aspirated material.

Aspiration will more commonly affect the right lung because the right main bronchus is more vertical than the left main bronchus. Aspiration may lead to a variety of clinical conditions, including chemical pneumonitis, bacterial pneumonia, or adult respiratory distress syndrome.

Mechanical ventilation may be required for prolonged periods. The main controversies surrounding treatment decisions involve the decision to use antibiotics and steroids.

Antibiotics should only be used if pneumonia develops, as early antibiotics may lead to the selection of virulent bacteria including pseudomonas. There is no evidence that using steroids either reduces mortality or improves outcome. Ventilator-associated pneumonia VAP is predominantly caused by microaspiration and strategies should be used to reduce the risk of VAP. Tracheal tubes, which allow subglottic secretion drainage, help reduce the incidence of VAP and subsequently the duration of mechanical ventilation.

The recent NAP4 2 study shows ongoing evidence of aspiration occurring in patients with recognized risk factors. NAP4 2 found that an excess of aspiration cases involved emergency surgery and trainee anaesthetists.

Fifteen of the 29 cases with primary or secondary aspiration were anaesthetized by trainees. Perhaps it is not surprising that trainees and emergency surgery supplied an excess of cases. Emergency surgery significantly increases the risk of aspiration and arguably trainees may anaesthetize a higher proportion of emergency cases than consultants. Worryingly the NAP4 2 questionnaire found the failure of risk assessment to be a persistent theme.

Of the 23 cases of primary anaesthesia-related aspiration, only 10 However, retrospectively 9 of the 11 patients initially described as having no risk factors had at least one risk factor for aspiration. Indeed of all the patients who aspirated, 27 of 29 patients had identifiable risk factors Developing strategies to reduce the harm associated with aspiration require us to consider the reasons why risk assessment of aspiration fails to influence the anaesthetic technique.

Even emergency patients with the highest risk have a relatively low risk of aspiration in absolute terms. The first few times an anaesthetist chooses not to use recommended strategies to mitigate the risk of aspiration may result in no harm, thus confirming the belief that aspiration risk is overestimated.

The high proportion of cases involving trainees brings into question the supervision, departmental support, training, and culture within hospitals. As with other risk—benefit analyses, aspiration risk can be thought of as a continuous spectrum.

There are patients with low risk and some with high risk, but there is also likely to be many cases with an intermediate risk. Such a spectrum will reduce the effectiveness of a standardized risk assessment tool to inform decision-making. As is often the case during surgery, any of the incidents in NAP4 involve non-technical skills and human factors. The morbidity associated with oral endotracheal intubation outweighed the potential benefits. Firstly, the patient aspirated non-particulate matter and bronchoscopic suctioning was not indicated, obviating the need for intubation for this purpose.

Secondly, oxygen saturation after aspiration remained adequate. Brief and profound hypoxia in healthy humans is well tolerated in the absence of circulatory compromise [ 15 ]. Thirdly, the patient maintained spontaneous breathing, and positive pressure ventilation was not applied. Positive pressure ventilation applied through an oral endotracheal tube even after suctioning could potentially further drive incompletely suctioned aspirates deeper into the smaller airways.

The risk of lung contamination in a spontaneously breathing patient may thus be lower than that in a patient under positive pressure ventilation. Fourthly, the procedure did not require general anaesthesia and was of short duration. Colonoscopy involves colonic insufflation of gas to distend the colon and frequently requires application of abdominal pressure and positional change which may increase the risk of aspiration [ 16 , 17 ].

Anaesthesiologists and proceduralists both need to be mindful of factors that predispose patients to aspiration during procedural sedation. Coughing during procedural sedation has been suggested as a surrogate marker of impending aspiration with supine positioning further heightening the risk [ 4 ]. When prodromal signs of vomiting such as coughing and change in respiratory patterns are evident, prevention of overt aspiration should be initiated immediately.

This includes reduction in bowel distension and reduction or cessation in administration of sedatives [ 18 ]. Change in body positioning may also be helpful. It is still unclear what constitutes the most protective body positioning.

Some advocate sitting or semi-recumbent position [ 19 , 20 ], while others advocate left lateral position [ 21 ] or steep Trendelenburg position [ 22 ].

In this case, positioning from left lateral to supine was likely the trigger factor for vomiting and aspiration. A nasopharyngeal airway was also inserted at the corresponding time. An inappropriately long nasopharyngeal airway may irritate the coughing or gag reflex which may predispose the patient to vomiting [ 23 ]. Although the length of the nasopharyngeal airway was short, it may have still contributed to the gag reflex. Prevention of aspiration can be achieved by promoting gastric emptying with pharmacological agents or removing gastric contents with nasogastric intubation before commencement of anaesthesia.

Nasogastric intubation may also lead to perioperative aspiration [ 24 ], and whether to leave the nasogastric tube in situ or to remove it prior to commencement of anaesthesia remains a matter of contention [ 25 ]. Preoperative gastric ultrasound to quantify residual gastric content shows promise in potentially offering preoperative identification of those at risk of pulmonary aspiration.

In an Australian study, 4. Published management strategies of aspiration during anaesthesia have been generally written for cases requiring general anaesthesia. Aspiration that occurs during procedural sedation may not necessarily benefit from the same approach.

While aspiration containing particulate matter should be managed with endotracheal intubation [ 1 ], aspiration of non-particulate matter may be more safely managed without immediate oral endotracheal intubation if adequate oxygen saturation is maintained. In a haemodynamically unstable patient following aspiration, endotracheal intubation should be strongly considered as this is a predictor for ventilatory support in the intensive care unit [ 1 , 11 ]. Developing a guideline specifically for management of aspiration during procedural sedation would be beneficial.

In conclusion, anaesthesiologists need to be mindful of factors that raise the risk of aspiration during procedural sedation. Management of pulmonary aspiration. Best Pract Res Clin Anaesthesiol. PubMed Article Google Scholar. Bronchoaspiration: incidence, consequences and management. Eur J Anaesthesiol. Pulmonary aspiration during procedural sedation: a comprehensive systematic review. Br J Anaesth.

Prospective description of coughing, hemodynamic changes, and oxygen desaturation during endoscopic sedation. Dig Dis Sci. Australian and New Zealand College of Anaesthetists. Adverse events during monitored anesthesia care for GI endoscopy: an 8-year experience.

Gastrointest Endosc. Complications following colonoscopy with anesthesia assistance: a population-based analysis. Pulmonary scintigraphy for diagnosis of aspiration during intravenous propofol anaesthesia for colonoscopy.

Mendelson CL. The aspiration of stomach contents into the lungs during obstetric anesthesia. Am J Obstet Gynecol. Clinical significance of pulmonary aspiration during the perioperative period. Aspiration during anaesthesia in the first incidents reported to webAIRS. Anaesth Intensive Care. DeLegge MH. Aspiration pneumonia: incidence, mortality, and at-risk populations. J Parenter Enteral Nutr.