|Year : 2022 | Volume
| Issue : 4 | Page : 561-564
Gastric ultrasonography in assessment and quantification of gastric contents in fasting diabetic and nondiabetic patients
Delma D Cunha1, Padubidri S Balakrishna Achar2, T Gurumurthy3, Manasa Acharya2
1 Department of Anaesthesiology and Critical Care, Yenepoya Medical College Deralakatte, Mangalore, Karnataka, India
2 Department of Anaesthesiology, Father Muller Medical College, Mangalore, Karnataka, India
3 Department of Anaesthesiology, Kasturba Medical College, Mangalore, Karnataka, India
|Date of Submission||02-Feb-2021|
|Date of Decision||05-Jul-2021|
|Date of Acceptance||05-Jul-2021|
|Date of Web Publication||22-Jan-2022|
Padubidri S Balakrishna Achar
Department of Anaesthesiology, Father Muller Medical College, Mangalore, Karnataka
Source of Support: None, Conflict of Interest: None
Context: Gastric ultrasound is an emerging point-of-care diagnostic tool to examine stomach contents and determine pulmonary aspiration risk at the bedside. This is helpful in guiding airway and/or anesthetic management in the acute care setting, when nil per oral (NPO) status is doubtful or unknown or patient has conditions or comorbidities that affect gastric emptying. Aims: The objectives of the study were to evaluate and quantify the gastric contents and grade the fullness of the stomach in fasting patients. Settings and Design: This was an observational, analytical study conducted on patients who presented for elective surgeries who were fasted for 8 hours for solids and 6 hours for clear liquids. Materials and Methods: Adult patients aged between 18 and 70 years of American Society of Anesthesiology physical status 1–3 were included in the study. Gastric ultrasonography was performed and gastric volume was calculated. Data were entered in Microsoft Excel 2007 and analyzed using SPSS version 22.0. Results: Our study included a total of eighty subjects. The mean age in the diabetic group was 49.3 ± 16.4 years and in the nondiabetic group 49.4 ± 16.8 years. Despite fasting status, 75% of the subjects were found to have Grade 1 (up to 100 ml) gastric contents on ultrasonography. The data were found to be statistically significant with P < 0.05. There was no significant correlation of age and ultrasonography findings. However, body mass index of the patient was found to have a strong correlation with gastric content and its volume (P < 0.0001). Conclusion: In the current practice, NPO status, especially for emergency cases, is elicited via history which is unreliable, and in individuals at higher risk for delayed gastric emptying, this may pose a greater threat for aspiration. Using gastric ultrasonography as a screening tool prior to planning the anesthetic induction and technique can help avoid unnecessary perioperative complications.
Keywords: Acid aspiration syndrome, aspiration pneumonia, diabetes mellitus, gastric acid aspiration syndrome, ultrasonography
|How to cite this article:|
D Cunha D, Balakrishna Achar PS, Gurumurthy T, Acharya M. Gastric ultrasonography in assessment and quantification of gastric contents in fasting diabetic and nondiabetic patients. Med J DY Patil Vidyapeeth 2022;15:561-4
|How to cite this URL:|
D Cunha D, Balakrishna Achar PS, Gurumurthy T, Acharya M. Gastric ultrasonography in assessment and quantification of gastric contents in fasting diabetic and nondiabetic patients. Med J DY Patil Vidyapeeth [serial online] 2022 [cited 2022 Aug 11];15:561-4. Available from: https://www.mjdrdypv.org/text.asp?2022/15/4/561/336324
| Introduction|| |
Increased gastric content volume may contribute to pulmonary aspiration, one of the most feared complications related to general anesthesia. Preoperative fasting guidelines were, therefore, proposed in order to reduce gastric content volume in patients undergoing elective surgeries and consequently to minimize the risk of regurgitation and pulmonary aspiration. Aspiration of gastric contents (solids, particulate matter, large volume, or higher acid content of the aspirate) results in 9% of anesthesia-related deaths and 50% of deaths from airway management incidents, according to audit on pulmonary aspiration by Royal College of Anaesthetists, UK.
Gastric ultrasound (GUS) is an emerging point-of-care diagnostic tool to examine stomach contents and determine pulmonary aspiration risk at the bedside., This is helpful in guiding airway and/or anesthetic management in the acute care setting, when nil per oral (NPO) status is doubtful or unknown or patient has conditions or comorbidities that affect gastric emptying. A point-of-care ultrasound application has defined purpose for improving patient outcome, focused, goal-oriented findings, easily recognizable results, and can be easily learned and quickly performed at the patient's bedside. GUS complies with these characteristics and can be performed by anesthesiologists with a minimum of 33 scans, required by trainees to obtain an accuracy of 90%, which suggests that it is easy to learn.
Gastroparesis is a medical condition defined as delayed gastric emptying in the absence of mechanical obstruction, for example, diabetes mellitus (DM). Existence of the remaining food in the stomach 12 h after fasting represents gastroparesis. Hence, diabetic patients posted for surgeries can be considered full stomach and can be evaluated for gastric contents by bedside GUS. Delayed gastric emptying is found in both Type 1 and Type 2 DM with a higher prevalence in the former. Studies have shown a correlation of gastroparesis with duration of DM and other factors such as age and body mass index (BMI) and medical conditions affecting gastric emptying.
With this background information, we decided to assess and compare the role of GUS in diabetic patients and nondiabetic patients posted for elective surgeries. The primary objective of this study was to assess and quantify the gastric contents in diabetic and nondiabetic fasting patients posted for elective surgeries. The secondary outcome was to correlate fasting gastric volume and contents with age, BMI, and duration of DM.
| Materials and Methods|| |
This was a prospective, observational, hospital-based, analytical study conducted in the preanesthesia room of the operation theater (OT) complex of a tertiary care center in Mangalore. Study subjects included patients who presented for elective surgeries after fasting for 6 hours for solids and 4 hours for clear liquids. The study was conducted over a period of 3 months from January to March 2020 after obtaining Institutional Ethical Committee clearance (FMIEC/CCM/47/2020). Adult patients (both male and female) aged between 18 and 70 years of American Society of Anesthesiology (ASA) physical status 1–3 posted for elective surgeries were included in the study. Diabetic individuals were identified as per the diagnostic criteria by the American Diabetes Association which include the following: a fasting plasma glucose level of 126 mg/dL (7.0 mmol/L) or higher or a 2-h plasma glucose level of 200 mg/dL (11.1 mmol/L) or higher.
Pregnant women, morbidly obese patients, and patients unable to turn and lie in right lateral position were excluded from the study.
All the patients underwent routine preanesthetic checkup for their posted surgeries the day before. Vitals and investigation review were done. They were given information about the GUS examination to be done the next day to assess gastric volume. Written informed consent was obtained. Demographic and other details of the patients such as hospital ID, number of hours of fasting, and whether diabetic or not were recorded in a validated pro forma. Patients received injection ondansetron 4 mg IV before shifting to OT.
The ultrasound examination was performed in the presurgical waiting area by a senior anesthesiologist trained in ultrasonography in the presence of a radiologist in the OT complex prior to being wheeled into the OT. PHILIPS® portable ultrasound machine was used to conduct the study. A curved array low-frequency (2–5 MHz) probe was used in abdominal scan mode settings. The epigastrium was scanned in a sagittal plane sweeping the transducer from the left to right subcostal margins. Scanning was done in the supine position followed by right lateral position. The gastric antrum was identified just below the left lobe of the liver and pancreas where the aorta/Inferior venacava serve as important vascular landmarks.
According to the appearance on the ultrasound, the contents were identified as either empty, clear liquids, or solids. Cross-sectional area (CSA) was measured using the freehand tracing tool built into the ultrasound machine. Gastric volume was calculated using the formula described by Perlas et al.
Volume (ml) =27.0 + 14.6 × right lateral CSA − 1.28 × age.
The sample size was calculated as 80 after performing a pilot study on 10 patients in each of the two groups – diabetics and nondiabetics for screening GUS in fasting state, keeping the power of the study as 80% and α error as 5%.
Data was entered in Microsoft Excel 2007 and analyzed using IBM SPSS Statistics for Windows version 22.0. Armonk, NY: IBM Corp.
| Results|| |
Our study included a total of eighty subjects with comparable demographics, as shown in [Table 1]. The mean age in the diabetic group was 49.3 ± 16.4 years and in the nondiabetic group 49.4 ± 16.8 years.
Despite fasting status, 75% of the subjects were found to have Grade 1 (up to 100 ml) gastric contents on ultrasonography [Table 2]. Contents were clear fluid in all the subjects with gastric contents, as shown in [Table 3]. Only 15% of the total study sample (all ASA I) were found to have Grade 0 gastric volume after fasting state. The data were found to be statistically significant with P = 0.04.
There was no significant correlation of age and ultrasonography findings [Table 4]. However, BMI of the patient was found to have a strong correlation with gastric content and its volume [Table 5].
In the diabetic group, data of the subjects were further analyzed based on mean duration of diabetes, as shown in [Table 6], which was 5.6 ± 1.8 years and 16.2 ± 4.3 years, respectively.
| Discussion|| |
The objective of this study was to assess and quantify the gastric contents in diabetic and nondiabetic fasting patients posted for elective surgeries. The secondary outcome was to correlate fasting gastric volume and contents with age, BMI, and duration of DM.
Acute intraoperative aspiration of gastric contents is a feared and potentially fatal complication associated with morbidity due to lung injury resulting from pneumonitis or aspiration pneumonia. The severity of lung injury can be attributed to the volume, nature, and acidity of the gastric contents. According to many authors, the presence of gastric volume >1.5 ml/kg poses a risk for aspiration requiring intervention.,,,, Our study found that despite fasting status, 75% of the subjects had Grade 1 (up to 100 ml) gastric contents on ultrasonography.
While certain anesthetic agents themselves are known to decrease lower esophageal sphincter tone, there are other conditions such as obesity, diabetes, and cancer which also increase the risk of aspiration under general anesthesia., Zhou et al. in a study found that the prevalence of full stomach was higher in diabetic patients due to delayed gastric emptying. Similarly, in our study, the patients with significant gastric volume were either diabetic (40%) or belonging to ASA II/III physical status (35%), and 59% were found to be overweight or obese.
Garima et al. using bedside GUS on adult patients presenting for elective surgery found that fasting for 10 h did not guarantee an empty stomach and comorbidities like DM appeared more prone to have unsafe gastric contents
Our study similarly confirms that diabetes and increased BMI are both criteria that increase the risk of aspiration due to delayed gastric emptying despite overnight fasting with statistical analysis revealing significance of P < 0.05.
Reviews show that patients posted for emergency surgeries are found to have four times greater chances of aspiration. Van de Putte et al. after analyzing aspiration risk assessment using GUS concluded that anesthetic management changed in nearly 65% of cases, thus concluding that GUS may be a useful diagnostic addition to standard patient assessment. Hence, especially in emergency setup, risk assessment should not be just on history alone. Gastric ultrasonography must be made a mandatory tool in diabetic patients and individuals with higher BMI for risk assessment and stratification in OTs for both elective and emergency procedures. This can enable elective cases to be either postponed or an alternative method such as regional anesthesia to be planned.
| Conclusion|| |
In the current practice, NPO status, especially for emergency cases, is elicited via history which is unreliable, and in individuals at higher risk for delayed gastric emptying, this may pose a greater threat for aspiration. Using gastric ultrasonography as a screening tool prior to planning the anesthetic induction and technique can help avoid unnecessary perioperative complications.
Being an observational study, volume of the gastric contents (as measured by ultrasonography) could not be validated by nasogastric aspiration and quantification. Moreover, data bias could be attributed to small sample size and interobserver variability while performing ultrasonography as the freeze time antrum measurement is subject to variation during gut peristalsis. Comparison of gastric volume between Type 1 and Type 2 DM subjects would have provided further information regarding diabetic gastropathy and delayed emptying.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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