Gastric content and perioperative pulmonary aspiration in patients with diabetes mellitus: a scoping review

Risks of peri- and postoperative complications with glucagon-like peptide-1 receptor agonists

AIM

To assess whether adults with diabetes on oral hypoglycaemic agents undergoing general endotracheal anaesthesia during nine common surgical procedures who are glucagon-like peptide-1 receptor agonist (GLP1-RA) users, compared with non-users, are at increased risk of six peri- and post-procedure complications.

MATERIALS AND METHODS

A retrospective observational cohort analysis of over 130 million deidentified US adults with diabetes (defined as being on oral hypoglycaemic agents) from a nationally representative electronic health dataset between 1 January 2015 and 1 April 2023 was analysed. Cohorts were matched by high-dimensionality propensity scoring. We compared the odds of six peri- and postoperative complications in GLP1-RA users and non-users. A sensitivity analysis compared these odds in GLP1-RA users to non-users with diabetes and obesity. We measured the odds of (a) a composite outcome of postoperative decelerated gastric emptying, including antiemetic use, ileus within 7 days post-procedure, gastroparesis diagnosis, gastric emptying study; (b) postoperative aspiration or pneumonitis; (c) severe respiratory failure; (d) postoperative hypoglycaemia; (e) inpatient mortality; and (f) 30-day mortality.

RESULTS

Among 13 361 adults with diabetes, 16.5% were treated with a GLP1-RA. In the high-dimensionality propensity score-matched cohort, GLP1-RA users had a lower risk of peri- and postoperative complications for decelerated gastric emptying and antiemetic use compared with non-users. The risk of ileus within 7 days, aspiration/pneumonitis, hypoglycaemia and 30-day mortality were not different. A sensitivity analysis showed similar findings in patients with diabetes and obesity.

CONCLUSION

No increased risk of peri- and postoperative complications in GLP1-RA users undergoing surgery with general endotracheal anaesthesia was identified.

Effect of lixisenatide on liquid gastric emptying in type 2 diabetes - Implications for the use of GLP-1 receptor agonists before procedures

Gastric emptying of a glucose drink was measured in people with type 2 diabetes given lixisenatide (20 μg/day or placebo) for 8 weeks. Intragastric retention at 240 min (2 (0-11)% vs 48 (3-97)%; P < 0.0001) was much greater with lixisenatide than placebo. Accordingly, lixisenatide may delay liquid gastric emptying markedly.

Preoperative fasting and the risk of pulmonary aspiration-a narrative review of historical concepts, physiological effects, and new perspectives

In the early days of anaesthesia, the fasting period for liquids was kept short. By the mid-20th century 'nil by mouth after midnight' had become routine as the principles of the management of 'full stomach' emergencies were extended to include elective healthy patients. Back then, no distinction was made between the withholding of liquids and solids. Towards the end of the last century, recommendations of professional anaesthesiology bodies began to reduce the fasting time of clear liquids to 2 h. This reduction in fasting time was based on the understanding that gastric emptying of clear liquids is rapid, exponential, and proportional to the current filling state of the stomach. Furthermore, there was no evidence of a link between drinking clear liquids and the risk of aspiration. Indeed, most instances of aspiration are caused by failure to identify aspiration risk factors and adjust the anaesthetic technique accordingly. In contrast, long periods of liquid withdrawal cause discomfort and may also lead to serious postoperative complications. Despite this, more than two decades after the introduction of the 2 h limit, patients still fast for a median of up to 12 h before anaesthesia, mainly because of organisational issues. Therefore, some hospitals have decided to allow patients to drink clear liquids within 2 h of induction of anaesthesia. Well-designed clinical trials should investigate whether these concepts are safe in patients scheduled for anaesthesia or procedural sedation, focusing on both aspiration risk and complications of prolonged fasting.

Baseline Gastric Volume in Fasting Diabetic Patients Is Not Higher than That in Nondiabetic Patients: A Cross-sectional Noninferiority Study

BACKGROUND

The physiology of diabetes mellitus can increase the risk of perioperative aspiration, but there is limited and contradictory evidence on the incidence of "full stomach" in fasting diabetic patients. The aim of this study is to assess the baseline gastric content (using gastric ultrasound) in diabetic and nondiabetic patients scheduled for elective surgery who have followed standard preoperative fasting instructions.

METHODS

This was a prospective, noninferiority study of 180 patients (84 diabetic and 96 nondiabetic patients). Bedside ultrasound was used for qualitative and quantitative assessment of the gastric antrum in the supine and right lateral decubitus positions. Fasting gastric volume was estimated based on the cross-sectional area of the gastric antrum and a validated model. The hypothesis was that diabetic patients would not have a higher baseline fasting gastric volume compared to nondiabetic patients, with a noninferiority margin of 0.4 ml/kg. Secondary aims included the comparison of the incidence of full stomach (solid content or more than 1.5 mL/kg of clear fluid), estimation of the 95th percentile of the gastric volume distribution in both groups, and examination of the association between gastric volume, glycemic control, and diabetic comorbidities.

RESULTS

The baseline gastric volume was not higher in diabetic patients (0.81 ± 0.61 ml/kg) compared to nondiabetic patients (0.87 ± 0.53 ml/kg) with a mean difference of -0.07 ml/kg (95% CI, -0.24 to 0.10 ml/kg). A total of 13 (15.5%) diabetic and 11 (11.5%) nondiabetic patients presented more than 1.5 ml/kg of gastric volume (95% CI for difference, -7.1 to 15.2%). There was little correlation between the gastric volume and either the time since diagnosis or HbA1C.

CONCLUSIONS

The data suggest that the baseline gastric volume in diabetic patients who have followed standard fasting instructions is not higher than that in nondiabetic patients.

EDITOR’S PERSPECTIVE

Perioperative use of glucagon-like peptide-1 receptor agonists and sodium-glucose cotransporter 2 inhibitors for diabetes mellitus

Type 2 diabetes mellitus is an increasingly common long-term condition, and suboptimal perioperative glycaemic control can lead to postoperative harms. The advent of new antidiabetic drugs, in particular glucagon-like peptide-1 (GLP-1) receptor agonists and sodium-glucose cotransporter 2 (SGLT2) inhibitors, has enabled perioperative continuation of these medicines, thus avoiding the harms of variable rate i.v. insulin infusions whilst providing glycaemic control. There are differences between medicines regulatory agencies and organisations on how these classes that are most often used to treat diabetes mellitus, (but also in the case of SGLT2 inhibitors chronic kidney disease and heart failure in those without diabetes) should be managed in the perioperative period. In this commentary, we argue that GLP-1 receptor agonists should continue during the perioperative period and that SGLT2 inhibitors should only be omitted the day prior to a planned procedure . The reasons for the differing advice advocated between regulatory agencies and what anaesthetic practitioners should do in the face of continuing uncertainty are discussed.

Gastric point-of-care ultrasonography in patients undergoing radical gastrointestinal surgery before anesthetic induction: an observational cohort study

BACKGROUND

Pulmonary aspiration of gastric contents is a serious perioperative complication. Patients with gastric cancer may experience delayed gastric emptying. However, the role of qualitative and quantitative gastric ultrasound assessments in this patient population before anesthesia induction has not yet been determined.

METHODS

Adult patients with gastrointestinal cancer were recruited and examined using gastric point-of-care ultrasound (POCUS) before anesthetic induction from March 2023 to August 2023 in a tertiary cancer center. Three hundred patients with gastric cancer were conducted with POCUS prior to induction, and three hundred patients with colorectal cancer were included as controls. The cross-sectional area (CSA) of the gastric antrum and gastric volumes (GV) were measured and calculated. We determined the nature of the gastric contents and classified the antrum using a 3-point grading system. A ratio of GV to body weight > 1.5mL/Kg was defined as a high risk of aspiration.

RESULTS

In patients with gastric cancer, 70 patients were classified as grade 2 (23%, including 6 patients with solid gastric contents) and 63 patients (21%) were identified as having a high risk of aspiration. Whereas in patients with colorectal cancer, only 11 patients were classified as grade 2 (3.7%), and 27 patients (9.7%) were identified as having a high risk of aspiration. A larger tumor size (OR:1.169, 95% CI 1.045-1.307, P = 0.006), tumor located in antrum (OR:2.304, 95% CI 1.169-4.539,P = 0.016), gastrointestinal obstruction (OR:21.633, 95% CI 4.199-111.443, P < 0.0001) and more lymph node metastasis (OR:2.261, 95% CI 1.062-4.812, P = 0.034) were found to be positively while tumor site at cardia (OR:0.096, 95% CI 0.019-0.464, P = 0.004) was negatively associated with high aspiration risk in patients with gastric cancer.

CONCLUSION

The Gastric POCUS prior to induction provides an assessment of the status of gastric emptying and can identify the patients at high risk of aspiration, especially those with gastric cancer.

TRIAL REGISTRATION

Chinese Clinical Trial Registry ( www.chictr.org.cn ) identifier: ChiCTR2300069242; registered 10 March 2023.

State of the Art in Pediatric Anesthesia: A Narrative Review about the Use of Preoperative Time

This review delves into the challenge of pediatric anesthesia, underscoring the necessity for tailored perioperative approaches due to children's distinctive anatomical and physiological characteristics. Because of the vulnerability of pediatric patients to critical incidents during anesthesia, provider skills are of primary importance. Yet, almost equal importance must be granted to the adoption of a careful preanesthetic mindset toward patients and their families that recognizes the interwoven relationship between children and parents. In this paper, the preoperative evaluation process is thoroughly examined, from the first interaction with the child to the operating day. This evaluation process includes a detailed exploration of the medical history of the patient, physical examination, optimization of preoperative therapy, and adherence to updated fasting management guidelines. This process extends to considering pharmacological or drug-free premedication, focusing on the importance of preanesthesia re-evaluation. Structural resources play a critical role in pediatric anesthesia; components of this role include emphasizing the creation of child-friendly environments and ensuring appropriate support facilities. The results of this paper support the need for standardized protocols and guidelines and encourage the centralization of practices to enhance clinical efficacy.

Development and validation of a novel nomogram model to assess the risk of gastric contents in outpatients undergoing elective sedative gastrointestinal endoscopy procedures

BACKGROUND

Gastric contents may contribute to patients' aspiration during anesthesia. Ultrasound can accurately assess the risk of gastric contents in patients undergoing sedative gastrointestinal endoscopy (GIE) procedures, but its efficiency is limited. Therefore, developing an accurate and efficient model to predict gastric contents in outpatients undergoing elective sedative GIE procedures is greatly desirable.

METHODS

This study retrospectively analyzed 1501 patients undergoing sedative GIE procedures. Gastric contents were observed under direct gastroscopic vision and suctioned through the endoscope. High-risk gastric contents were defined as having solid content or liquid volume > 25 ml and pH < 2.5; otherwise, they were considered low-risk gastric contents. Univariate analysis and multivariate analysis were used to select the independent risk factors to predict high-risk gastric contents. Based on the selected independent risk factors, we assigned values to each independent risk factor and established a novel nomogram. The performance of the nomogram was verified in the testing cohort by the metrics of discrimination, calibration, and clinical usefulness. In addition, an online accessible web calculator was constructed.

RESULTS

We found BMI, cerebral infarction, cirrhosis, male, age, diabetes, and gastroesophageal reflux disease were risk factors for gastric contents. The AUROCs were 0.911 and 0.864 in the development and testing cohort, respectively. Moreover, the nomogram showed good calibration ability. Decision curve analysis and Clinical impact curve demonstrated that the predictive nomogram was clinically useful. The website of the nomogram was https://medication.shinyapps.io/dynnomapp/.

CONCLUSIONS

This study demonstrates that clinical variables can be combined with algorithmic techniques to predict gastric contents in outpatients. Nomogram was constructed from routine variables, and the web calculator had excellent clinical applicability to assess the risk of gastric contents accurately and efficiently in outpatients, assist anesthesiologists in assessment and identify the most appropriate patients for ultrasound.

Perioperative Nutritional Management in Enhanced Recovery after Bariatric Surgery

Obesity is a crucial health problem because it leads to several chronic diseases with an increased risk of mortality and it is very hard to reverse with conventional treatment including changes in lifestyle and pharmacotherapy. Bariatric surgery (BS), comprising a range of various surgical procedures that modify the digestive tract favouring weight loss, is considered the most effective medical intervention to counteract severe obesity, especially in the presence of metabolic comorbidities. The Enhanced Recovery After Bariatric Surgery (ERABS) protocols include a set of recommendations that can be applied before and after BS. The primary aim of ERABS protocols is to facilitate and expedite the recovery process while enhancing the overall effectiveness of bariatric procedures. ERABS protocols include indications about preoperative fasting as well as on how to feed the patient on the day of the intervention, and how to nourish and hydrate in the days after BS. This narrative review examines the application, the feasibility and the efficacy of ERABS protocols applied to the field of nutrition. We found that ERABS protocols, in particular not fasting the patient before the surgery, are often not correctly applied for reasons that are not evidence-based. Furthermore, we identified some gaps in the research about some practises that could be implemented in the presence of additional evidence.

Ultrasonographic Assessment of Gastric Volume in Fasted Patients Undergoing Gastrointestinal Endoscopy Under Sedation

Purpose

In this prospective observational study, an ultrasonographic measurement of antral cross-sectional area (ACSA) was conducted to evaluate the gastric content and volume as well as to identify high-risk stomach in non-pregnant adult surgical patients adhering to preanesthetic fasting guidelines.

Patients and Methods

Fasted patients undergoing gastrointestinal endoscopy under sedation were included. Ultrasonographic measurements of ACSA were conducted in both semi-recumbent and right lateral decubitus positions before endoscopic procedures. Gastroscopy was employed to guide the measurement of suctioned gastric volume (GV). Ultrasonography was performed to assess gastric contents and identify patients with high-risk stomach. The relationship between ACSA and suctioned GV was also evaluated.

Results

ACSA was evaluated in 736 out of 782 patients. A significant positive correlation was discovered between ACSA in the right lateral decubitus position and suctioned GV, which was more reliable than in the semi-recumbent position. To analyze high-risk stomach with a GV > 100 mL, the cutoff value of ACSA in the right lateral decubitus was found to be 7.5 cm2, with the AUC, sensitivity and specificity of 0.80 (95% CI, 0.76-0.82; P<0.001), 82.4% and 67.3%, respectively. A novel mathematical model based on ACSA to estimate GV in non-pregnant fasted adults was presented.

Conclusion

Ultrasonographic measurement of ACSA can assist anesthesiologists in estimating the risk of pulmonary aspiration of gastric contents during general anesthesia and sedation.

Current practice in the perioperative management of patients with diabetes mellitus: a narrative review

The prevalence of diabetes is increasing, and patients with diabetes mellitus have both an increased likelihood of requiring surgery and of developing postoperative complications when they do. We summarise available evidence underpinning current guidelines on preoperative assessment and optimisation, perioperative management of prescribed insulin and oral hypoglycaemic medication, intraoperative glycaemic control, and postoperative patient care.

Ultrasound assessment of gastric contents and volume in patients undergoing endoscopic endonasal transsphenoidal surgery: a prospective observational study

Intraoperative ingestion of blood, cerebrospinal fluid, and irrigation fluid can lead to an increase in gastric volume, resulting in the potential risk of aspiration in patients after endoscopic endonasal transsphenoidal surgery (EETS). In this prospective observational study, we aimed to assess the volume of gastric contents in patients undergoing this neurosurgical procedure using ultrasound, and to determine the factors associated with volume change. Eighty-two patients diagnosed with pituitary adenoma were recruited consecutively. Semi-quantitative (Perlas scores: 0, 1 and 2) and quantitative (cross-sectional area, CSA) ultrasound assessments of the gastric antrum were performed immediately before and after surgery in the semi-recumbent and semi-recumbent right-lateral positions. Seven (8.5%) patients had antrum scores from preoperative grade 0 to postoperative grade 2; nine (11%) patients had antrum scores from preoperative grade 0 to postoperative grade 1. The mean ± standard deviation (SD) of increased gastric volume was 71.0 ± 33.1 mL and 236.5 ± 32.4 mL in postoperative grade 1 and 2 groups, respectively. Subgroup analysis showed that 11 (13.4%) patients (4 in grade 1 and all in grade 2) had postoperative estimated gastric volume > 1.5 mL kg^-1 (mean ± SD 3.08 ± 1.67, range 1.51-5.01 mL kg^-1). Logistic regression analysis revealed that older age, diabetes mellitus, and long surgical duration were independent risk factors for significant volume change (all P < 0.05). Our results showed a significant increase in gastric volume in some patients who underwent EETS. Bedside ultrasound measurements of gastric volume can be used to assess the postoperative aspiration risk, particularly in older diabetic patients with a longer surgical duration.

Gastric content and perioperative pulmonary aspiration in patients with diabetes mellitus: a scoping review

BACKGROUND

Gastric emptying may be delayed in patients with diabetes mellitus (DM). However, the incidence of full stomach in fasting patients with DM and their risk of pulmonary aspiration under anaesthesia is not well understood.

METHODS

A scoping review was undertaken to map the literature on aspiration risk in DM. A search was conducted in seven bibliographic databases, including MEDLINE and Embase, for original articles that studied aspiration risk, gastric emptying, or gastric content and volume. Selection and characterisation were performed by two independent reviewers using a predefined protocol registered externally.

RESULTS

The search identified 5063 unique records, and 16 studies (totalling 775 patients with DM) were selected: nine studied gastric emptying and seven studied gastric content or volume. There were no studies reporting the incidence of aspiration in subjects with DM. All nine studies reported delayed emptying in patients with DM compared with healthy controls. Amongst the seven studies that compared gastric residual content/volume (GRV) in the perioperative period, five reported clinically negligible GRV in both patients with DM and controls, whereas two observed a higher incidence of 'full' stomach in patients with DM.

CONCLUSIONS

The evidence concerning the aspiration risk for surgical patients with DM is based on a limited number of studies, mostly unblinded, reporting physiological data on gastric emptying and gastric volume as surrogate markers of aspiration risk. Data on fasting gastric content and volume in patients with DM are limited and contradictory; hence, the true risk of aspiration in fasting patients with DM is unknown.