Reinforcing the valuable role of gastric ultrasound for volume and content assessment: an observational study

Abstract Background Pulmonary aspiration is one of the most important complications in anesthesiology. Assessment of gastric content by ultrasound is a good method to quantify gastric volume and to determine the risk of intraoperative pulmonary aspiration. The aim of this study is to determine the accuracy of the gastric ultrasonography in the qualitative analysis of gastric content, mainly in the analysis of small amounts of liquid content. Methods Gastric ultrasound was performed to 36 patients before upper gastrointestinal endoscopy (UGI), making two longitudinal scans at the epigastric level, one in supine position and the other in right lateral decubitus position, measuring two diameters and the area of the gastric antrum and assessing the content characteristics determining whether it was an empty stomach or contained fluid or solid content. Subsequently, the ultrasound findings were compared with UGI findings. Results Gastric areas were analyzed by the trace and the lengths of the craniocaudal and anteroposterior axes concluding that there are no significant differences between the two methods. No statistically significant difference was found between UGI and US assessment technics. No statistically significant difference was found between the estimated volume by UGI and US. Conclusions Though our study has some limitations, qualitative analysis of gastric content using ultrasound followed by endoscopy enabled the conclusion that there are no differences in the qualitative assessment regarding these two techniques, supporting the important role of point-of-care gastric ultrasound (POCGUS) in the assessment of pulmonary aspiration risk by the anesthesiologist in the perioperative period.

Qualitative and quantitative ultrasound assessment of gastric content / Avaliação qualitativa e quantitativa do conteúdo gástrico através da ultrassonografia

Summary Objective: Pulmonary aspiration of the gastric contents is one of the most feared complications in anesthesia. Its prevention depends on preoperative fasting as well as identification of risky patients. A reliable diagnostic tool to assess gastric volume is currently lacking. The aim of this study performed on volunteers was to evaluate the feasibility of ultrasonography to identify qualitative and quantitative gastric content. Method: A standardized gastric scanning protocol was applied on 67 healthy volunteers to assess the gastric antrum in four different situations: fasting, after ingesting clear fluid, milk and a solid meal. A qualitative and quantitative assessment of the gastric content in the antrum was performed by a blinded sonographer. The antrum was considered either as empty, or containing clear or thick fluid, or solids. Total gastric volume was predicted based on a cross-sectional area of the antrum. A p-value less than 0.05 was considered statistically significant. Results: For each type of gastric content, the sonographic characteristics of the antrum and its content were described and illustrated. Sonographic qualitative assessment allowed to distinguish between an empty stomach and one with different kinds of meal. The predicted gastric volume was significantly larger after the consumption of any food source compared to fasting. Conclusion: Bedside sonography can determine the nature of gastric content. It is also possible to estimate the difference between an empty gastric antrum and one that has some food in it. Such information may be useful to estimate the risk of aspiration, particularly in situations when prandial status is unknown or uncertain.

Resumo Objetivo: A aspiração pulmonar do conteúdo gástrico é uma das complicações mais temidas em anestesia. A sua prevenção depende do jejum pré-operatório e da identificação dos pacientes de risco. Não há um método diagnóstico que possa acessar o conteúdo gástrico a qualquer momento. O objetivo deste estudo realizado em voluntários foi fazer uma avaliação qualitativa e quantitativa do conteúdo gástrico utilizando a ultrassonografia. Método: O estudo foi realizado em 67 voluntários utilizando uma técnica já descrita de avaliação do antro gástrico, em quatro diferentes situações: jejum, após a ingestão de líquido claro, leite ou refeição sólida. Foi feita uma avaliação qualitativa e quantitativa do conteúdo gástrico por um radiologista que desconhecia o estado gástrico do voluntário. O antro foi considerado vazio, contendo líquido claro ou espesso, ou sólido. O volume total do estômago foi calculado com base na área seccional do antro. Um valor de p<0,05 foi considerado estatisticamente significativo. Resultados: Para cada tipo de conteúdo gástrico, as características ultrassonográficas do antro e de seu conteúdo foram descritas e ilustradas. A avaliação qualitativa pode distinguir um estômago vazio de outros com diferentes conteúdos. O volume gástrico calculado foi significativamente maior após a ingestão de qualquer alimento em comparação com o jejum. Conclusão: A ultrassonografia à beira do leito pode determinar a natureza do conteúdo gástrico. Também foi possível diferenciar um antro vazio daquele com algum volume. Essas informações podem ser úteis na determinação do risco de aspiração gástrica, principalmente se a condição gástrica é desconhecida ou incerta.

Prevalência de risco moderado e alto de aspiração em pacientes hospitalizados e custo-efetividade da aplicação de protocolo preventivo / Prevalence of moderate and high risk of aspiration in hospitalized patients and cost-effectiveness of a preventive protocol application

Objetivo: O objetivo deste estudo foi estimar a prevalência de risco de broncoaspiração e a verificação do custo-efetividade da aplicação de protocolo preventivo. Métodos: Realizou-se estudo transversal de base hospitalar com amostra aleatória simples, seguido de análise estatística de associação e econômica do tipo árvore de decisão e custo-efetividade. Resultados: Verificou-se que a prevalência de risco de broncoaspiração é alta em hospitais gerais de grande porte, com a magnitude de 56%, e que a aplicação de protocolo preventivo com avaliação precoce de fonoaudiologista é custo-efetiva, com ganho de quase R$ 900,00 por internação hospitalar, além de redução de 0,15 dia de internação também por paciente, com razão de custo-efetividade incremental de economia de R$ 5.607,83. Conclusão: Conclui-se que a adoção de programa preventivo com a participação de fonoaudiólogos é altamente custo-efetiva.

Objective: The objective of this study was to estimate the prevalence of risk of aspiration and analysis of the cost effectiveness of the implementation of a preventive protocol. Methods: A cross-sectional study of hospital base with simple random sample, followed by statistical analysis of association and economic cost-effectiveness analysis using a decision tree. Results: It was found that the prevalence of risk of aspiration is high in general hospitals, with the magnitude of 56%, and that the implementation of preventive protocol with early evaluation of speech therapy is cost effective, with a gain of almost R$ 900.00 per hospitalization, as well as a reduction of 0.15 days of hospitalization also per patient, with incremental cost-effectiveness ratio of R$ 5,607.83 of economy. Conclusion: It is concluded that the adoption of preventive program with participation of speech therapy is highly cost-effective.

Prevention of aspiration of gastric contents during attempt in tracheal intubation in the semi-lateral and lateral positions / 世界急诊医学杂志（英文）

@#BACKGROUND: Pulmonary aspiration of gastric contents during tracheal intubation is a life-threatening complication in emergency patients. Rapid sequence intubation is commonly performed to prevent aspiration but is not associated with low risk of intubation related complications. Although it has been considered that aspiration can be prevented in the lateral position, few studies have evaluated the ability to prevent aspiration. Moreover, this position is not always a favorable position for tracheal intubation. If aspiration can be prevented in a clinically relevant semi-lateral position, it may be advantageous. We assessed the ability to prevent aspiration in the lateral position and various degrees of the semi-lateral position using a vomiting–regurgitation manikin model. METHODS: A manikin's head was placed in the neutral, simple extension, or sniffing position. The amount of aspirated saline into the bronchi during simulated vomiting was measured at semi-lateral position angles of 0o to 90o in 10o increments. The difference in the vertical height between the mouth corner and the inferior border of the vocal cord was measured radiologically at each semi-lateral position in the three head-neck positions. RESULTS: Pulmonary aspiration was prevented at the ≥70o, ≥80o, and 90o semi-lateral positions in the neutral, simple extension, and sniffing positions, respectively. The mouth was lower than the vocal cord in the semi-lateral position in which aspiration was prevented. CONCLUSION: The lateral or excessive semi-lateral position was necessary to protect the lung from aspiration in the head-neck positions commonly used for tracheal intubation. Prevention of aspiration was difficult within clinically relevant semi-lateral positions.

Amiodaron in atrial fibrillation: post coronary artery bypass graft / 世界急诊医学杂志（英文）

@#BACKGROUND: Atrial fibrilation (AF) is the most common complication following heart surgeries; it often occurs in patients after coronary artery bypass graft (CABG). The purpose of this review is to categorize prophylaxes or treatment by administration of Amiodaron in patients with CABG. DATA RESOURCES: We searched google scholar, pubmed, and Cochrane Library databases (the period 1970–2010) for articles on Amiodaron in CABG and cardiac surgery. A total of 1561 articles were identified, and 30 articles met the criteria and were enrolled in this review. RESULTS: Most studies supported Amiodarone for prophylaxi purpose in patients who were performed with CABG; few papers supported Amiodaron as a drug for treating CABG. The prophylaxis can decrease the incidence rate of AF in CABG, but if it uses as a treatment, the side effect of Amiodaron wil decrease because al of the patients wil not get Amiodarone. In the other hand use of Amiodarone as a treatment does not influence the length of hospital stay significantly but these kinds of study are so few. CONCLUSION: No appropriate therapeutic method has been defined for AF. At present, the common way of treating AF following cardiac surgery is mainly based on prophylaxis in medical books and references.

Techniques of rapid sequence induction and intubation at a university teaching hospital / 世界急诊医学杂志（英文）

BACKGROUND:Rapid sequence induction and intubation (RSII) is a medical procedure involving a prompt induction of general anesthesia by using cricoid pressure that prevents regurgitation of gastric contents. The factors affecting RSII are prophylaxis for aspiration, preoxygenation, drug and equipment preparation for RSII, ventilation after induction tillintubation and patient condition. We sometimes saw difficulties with the practice of this technique in our hospital operation theatres. The aim of this study was to assess the techniques of rapid sequence induction and intubation. METHODS:Hospital based observational study was conducted with a standardized checklist. Allpatients who were operated upon under general anesthesia during the study period were included. The techniques of RSII were observed during the induction of anesthesia by trained anesthetists. RESULTS:Altogether 140 patients were included in this study with a response rate of 95.2％. Prophylaxis was not given to 130 patients (92.2％), and appropriate drugs were not used for RSII in 73 patients (52.1％), equipments for difficult intubation in 21 (15％), suction machines with catheter not connected and turned on in 122 (87.1％), ventilation for patients after induction and before intubation in 41 (29.3％), cricoid pressure released before cuff inflation in 12 (12.1％), and difficult intubation in 8 (5.7％), respectively. RSII with cricoid pressure was applied appropriately in 94 (67.1％) patients, but cricoid pressure was not used in 46 (32.9％) patients. CONCLUSIONS:The techniques of rapid sequence induction and intubation was low. Training should be given for anesthetists about the techniques of RSII.

Pneumonia from pulmonary aspiration of an antihypertensive anesthetic premedication: A case report

A 75-year-old man was scheduled for a ray amputation of the left third metatarsal bone. He had a right middle cerebral artery (MCA) territory infarction 6 months earlier and had a history of dysphagia and repeated pneumonias. At 06:30 on the day of surgery, nifedipine was administered orally with small amounts of water and the patient coughed several times. Immediately after extubation at the end of anesthesia, an impacted drug-like material was noted in the endotracheal tube. It is likely that aspiration occurred at the time nifedifine was ingested the morning of surgery. The route of administration for premedications, should be modified when patients have perioperative risk factors for pulmonary aspiration.

Comparison of Glucose Concentration of Tracheal Secretions by Measuring Times and Feeding Methods in Enterally Fed Patients / 성인간호학회지

PURPOSE: The purpose of this study was to investigate differences between a pulmonary aspiration group and a non-pulmonary aspiration group in glucose concentration of tracheal secretions by measuring time and feeding methods. METHOD: The subjects were 36 ICU patients who were receiving formula via nasogastric tubes and had endotracheal tubes or tracheostomy tubes. Tracheal secretions were collected by connecting suction traps to a suction catheter in three different times(within 1 hour after feeding, between 1 to 2 hours after feeding, and between 2 to 3 hours after feeding) for 2 days, overall six times. Glucose concentration of tracheal secretions was measured with the glucometer(Accucheck II). RESULTS: Glucose concentration of tracheal secretions increased in progression after feeding. The mean of specimens collected last(between two to three hours after feeding) was shown to be the highest value(M= 61.61 mg/dl) in the pulmonary aspiration group. Significantly(p=.000) more subjects(94.44%) in the pulmonary aspiration group received formula via a 50cc syringe than those in the non-pulmonary aspiration group(22.22%). CONCLUSION: Critically ill patients may need more time for head-elevation after tube feeding to prevent pulmonary aspiration. In practice, enteral formula should not be given the patients via a 50cc syringe anymore, instead a feeding bag or infusion pump should be used to prevent pulmonary aspiration.

Comparison of Glucose Concentration of Tracheal Secretions by Measuring Times and Feeding Methods in Enterally Fed Patients / 성인간호학회지

PURPOSE: The purpose of this study was to investigate differences between a pulmonary aspiration group and a non-pulmonary aspiration group in glucose concentration of tracheal secretions by measuring time and feeding methods. METHOD: The subjects were 36 ICU patients who were receiving formula via nasogastric tubes and had endotracheal tubes or tracheostomy tubes. Tracheal secretions were collected by connecting suction traps to a suction catheter in three different times(within 1 hour after feeding, between 1 to 2 hours after feeding, and between 2 to 3 hours after feeding) for 2 days, overall six times. Glucose concentration of tracheal secretions was measured with the glucometer(Accucheck II). RESULTS: Glucose concentration of tracheal secretions increased in progression after feeding. The mean of specimens collected last(between two to three hours after feeding) was shown to be the highest value(M= 61.61 mg/dl) in the pulmonary aspiration group. Significantly(p=.000) more subjects(94.44%) in the pulmonary aspiration group received formula via a 50cc syringe than those in the non-pulmonary aspiration group(22.22%). CONCLUSION: Critically ill patients may need more time for head-elevation after tube feeding to prevent pulmonary aspiration. In practice, enteral formula should not be given the patients via a 50cc syringe anymore, instead a feeding bag or infusion pump should be used to prevent pulmonary aspiration.

Fiberoptic Bronchoscopic Treatment of Pulmonary Aspiration Occurring in a Child during Induction of Anesthesia: A case report / 대한마취과학회지

Pulmonary aspiration of gastric contents is a very rare but one of the most feared complications of anesthesia. The risk factors are gastroesophageal reflux, previous aspiration, renal failure, difficult intubation and trauma. The incidence of aspiration during anesthesia of children has been reported to be more common than adults. This report describes the case of a 7-year-old female patient who had experienced pulmonary aspiration during induction of anesthesia. With fiberoptic brochoscopy, the aspirates in both bronchi were carefully suctioned, and the following chest X-ray and blood gas findings improved. She was transferred to the intensive care unit for respiratory support and showed no further problems.

Clinical Implications of the Glucose Test Strip Method for Early Detection of Pulmonary Aspiration in Nasogastric Tube- Fed Patients / 간호학회지

PURPOSE: This study was performed to test the clinical usefulness of the glucose test strip method for early detection of pulmonary aspiration in tube fed patients. METHOD: The subjects for the study were 36 patients who were receiving enteral feedings and 39 patients who were not given enteral feedings. For the analysis, the tube fed patients were divided into two groups (clinically significant aspiration and no aspiration) according to criteria. RESULT: The mean glucose concentration of tracheal secretions from non enteral fed patients was 26.35mg/dl and were lower than those concentrations found in tube fed patients (32.75mg/dl). The mean glucose concentration of the aspiration group was 45.60mg/dl and the glucose concentration of the non aspiration group was 19.93mg/dl. The difference was statistically significant (t=2.163, p=. 038). More subjects in the no aspiration group (73%) than the aspiration group (56%) had glucose concentrations below 20mg/dl. After deleting the cases that had samples containing blood, glucose concentrations of tracheal aspirates were lower in both groups. CONCLUSION: The glucose level of the aspiration group was significantly lower than the no aspiration group and more subjects in the aspiration group had a glucose level higher than 101mg/dl. Therefore, the glucose test of tracheal secretions in tube fed patients could be a desirable test for screening for tracheal aspiration. Especially the patient who is showing repeatedly high glucose levels should not be given feedings until reassessment is completed.

Risk of Pulmonary Aspiration under General Inhalation Anesthesia with Laryngeal Mask Airway / 대한마취과학회지

BACKGROUND: The laryngeal mask airway(LMA) is a new type of airway that has many advantages compared with the tracheal tube, but its potential problem might be pulmonary aspiration. This study therefore was designed to investigate the risk of pulmonary aspiration during general anesthesia using LMA. METHODS: We studied 101 patients who received general inhalation anesthesia with LMA and mechanical positive pressure ventilation for gynecological operations. Methylene blue was poured into the oropharynx after the LMA was placed, and the presence or absence of the dye staining of the larynx, tracheal and main stem bronchi with fiberoptic bronchoscope through the LMA shaft lumen was observed one and/or two hour(s) after LMA placement. RESULTS: In two out of 101 patients there was staining of the larynx with methylene blue dye. One was one hour after and the other was stained two hours after LMA placement. CONCLUSIONS: Dye staining of the larynx suggests that even mechanical positive pressure ventilation with LMA placement have the risk of pulmonary aspiration. Therefore LMA is contraindicated if the stomach is not emptied.

Pulmonary Aspiration and Local Anesthetic Systemic Toxicity following Epidural Anesthesia / 대한마취과학회지

Aspiration can generate postoperative pulmonary morbidity of varing severity, depending on the type and volume of the aspirate. Epidural anesthesia can lead to local anesthetic systemic toxicity with mental change, followed by respiratory depression and abdominal and intercostal muscle weakness depressing the ability of the patient to cough and clear the airway. The authors experienced a case of pulmonary aspiration with systemic toxicity after epidural anesthesia for cesarean section. The chest X-ray showed alveolar consolidation at left lower lung field and arterial blood gases showed that PaO2 decreased. The exact causes of mental change and respiratory depression were unknown, but we suspected it lidocaine induced systemic toxicity due to vascular absorption, When airway reflexes are ineffective during face mask ventilation of the lungs, aspiration of clear oral secretions can generate small airway obstruction.