Pre-operative fasting: a nationwide survey of German anaesthesia departments

Effect of preoperative oral carbohydrates on insulin resistance in patients undergoing laparoscopic cholecystectomy: a randomized controlled trial

PURPOSE

The present research seeks to clarify the consequences of two specific preoperative oral carbohydrate (POC) amounts on insulin resistance (IR) and stomach evacuation in laparoscopic cholecystectomy (LC) patients.

METHODS

A total of 129 patients set for elective LC procedures were randomly assigned to a control group (C, n = 45), a 200 mL POC group (P1, n = 42), and a 400 mL POC group (P2, n = 42). The C group was fasted from midnight until surgery, whereas the P1 and P2 groups received their respective carbohydrate volumes 2-4 h before anesthesia. Fasting blood glucose, insulin, and glucagon concentrations were measured at three junctures. IR metrics were derived by employing the homeostasis model assessment. Gastric volume was measured before anesthesia using gastric ultrasound. Inter-group comparisons included IR indicators, subjective comfort scores, and hemodynamic data.

RESULTS

At T2, the C group exhibited reduced glucose concentrations compared to the P2 group (4.73 ± 0.64 vs. 5.26 ± 1.02 mmol/L, p < 0.05). The Perlas grading indicated that grade 1 was more prevalent in the P2 group than in the P1 and C groups (18 [42.9%] vs. 6 [14.3%] and 1 [2.2%], p < 0.05). Additionally, thirst and hunger metrics for the P2 group were notably reduced compared to the C group at both T2 and T3.

CONCLUSION

Administering either 200 mL or 400 mL of carbohydrates 2-4 h pre-surgery had no detectable impact on IR or gastric volume in LC patients.

TRIAL REGISTRATION

ChiCTR, ChiCTR2200065648. Registered January 13, 2023, http://www.chictr.org.cn .

Patient Education Regarding Fasting Recommendations to Shorten Fasting Times in Patients Undergoing Esophagogastroduodenoscopy: A Controlled Pilot Study

This study evaluated the applicability and efficacy of patient education regarding fasting recommendations to shorten fasting times in patients undergoing esophagogastroduodenoscopy (EGD). A prospective nonrandomized controlled pilot study was performed. The intervention group (IG) was educated by nurses to eat until 6 hours and drink until 2 hours before EGD. The control group (CG) received usual care. Outcomes were applicability as perceived by patients, adherence to fasting recommendations, gastric visibility, and patients' comfort. A total of 109 patients were included of whom 42 were IG patients (37%). Patients' perspectives on fasting, their experienced discomfort, professional support, and circadian rhythm influenced application of fasting recommendations. Adherence to length of fasting from foods improved with 3:14 hours ( p < .001) and from liquids with 5:22 hours ( p < .001) in the IG compared with the CG. Gastric visibility during EGD was better in the IG than in the CG. The IG patients experienced significant less thirst, hunger, headache, and anxiety. To successfully reduce fasting times, fasting education should include positive, individual instructions, which help patients apply the fasting recommendations within their biorhythm. Positive, concrete instructions by nurses shortened fasting times before EGD, which improved gastric visibility and reduced patient discomfort.

Abbreviated perioperative fasting management for elective fresh fracture surgery: guideline adherence analysis

BACKGROUND

Long-term fasting for elective surgery has been proven unnecessary based on established guidelines. Instead, preoperative carbohydrate loading 2 h before surgery and recommencing oral nutrition intake as soon as possible after surgery is recommended. This study was performed to analyze the compliance with and effect of abbreviated perioperative fasting management in patients undergoing surgical repair of fresh fractures based on current guidelines.

METHODS

Patients with fresh fractures were retrospectively analyzed from the prospectively collected database about perioperative managements based on enhanced recovery of surgery (ERAS) from May 2019 to July 2019 at our hospital. A carbohydrate-enriched beverage was recommended up to 2 h before surgery for all surgical patients except those with contraindications. Postoperatively, oral clear liquids were allowed once the patients had regained full consciousness, and solid food was allowed 1 to 2 h later according to the patients' willingness. The perioperative fasting time was recorded and the patients' subjective comfort with respect to thirst and hunger was assessed using an interview-assisted questionnaire.

RESULTS

In total, 306 patients were enrolled in this study. The compliance rate of preoperative carbohydrate loading was 71.6%, and 93.5% of patients began ingestion of oral liquids within 2 h after surgery. The median (interquartile range) preoperative fasting time for liquids and solids was 8 (5.2-12.9) and 19 (15.7-22) hours, respectively. The median postoperative fasting time for liquids and solids was 1 (0.5-1.9) and 2.8 (2.2-3.5) hours, respectively. A total of 70.3% and 74.2% of patients reported no thirst and hunger during the perioperative period, respectively. Logistic regression analysis showed that the preoperative fasting time for liquids was an independent risk factor for perioperative hunger. No risk factor was identified for perioperative thirst. No adverse events such as aspiration pneumonia or gastroesophageal reflux were observed.

CONCLUSIONS

In this study of a real clinical practice setting, abbreviated perioperative fasting management was carried out with high compliance in patients with fresh fractures. The preoperative fasting time should be further shortened to further improve patients' subjective comfort.

Optimized perioperative management (fast-track, ERAS) to enhance postoperative recovery in elective colorectal surgery

Aim

This manuscript provides information on the history, principles, and clinical results of Fast-track or ERAS concepts to optimize perioperative management (OPM).

Methods

With the focus on elective colorectal surgery description of the OPM concept and its elements for with special attention to the prevention of infectious complications and clinical results compared to traditional care will be given using recent systematic literature reviews. Additionally, clinical results for other major abdominal procedures are given.

Results

An optimized perioperative management protocol for elective colorectal resections will currently consist of 25 perioperative elements. These elements include the time from before hospital admission (patient education, screening, and treatment of possible risk factors like anemia, malnutrition, cessation of nicotine or alcohol abuse, optimization of concurrent systemic disease, physical prehabilitation, carbohydrate loading, adequate bowel preparation) to the preoperative period (shortened fasting, non-sedative premedication, prophylaxis of PONV and thromboembolic complications), intraoperative measures (systemic antibiotic prophylaxis, standardized anesthesia, normothermia and normovolemia, minimally invasive surgery, avoidance of drains and tubes) as well as postoperative actions (early oral feeding, enforced mobilization, early removal of a urinary catheter, stimulation of intestinal propulsion, control of hyperglycemia). Most of these elements are based on high-level evidence and will also have effects on the incidence of postoperative infectious complications.

Conclusion

Optimized perioperative management should be mandatory for elective surgery today as it enhances postoperative patient recovery, reduces morbidity and infectious complications.

Fasting habits over a 10-year period: An observational study on adherence to preoperative fasting and postoperative restoration of oral intake in 2 Dutch hospitals

BACKGROUND

Since 1999, international guidelines recommend fasting from solid foods up to 6 hours and clear liquids up to 2 hours before surgery. Early recovery after surgery programs recommend restoration of oral intake as soon as possible. This study determines adherence to these guidelines up to 20 years after its introduction.

METHODS

A 2-center observational study with a 10-year interval was performed in the Netherlands. In period 1 (2009), preoperative fasting time was observed as primary outcome. In period 2 (2019), preoperative fasting and postoperative restoration of oral intake were observed. Fasting times were collected using an interview-assisted questionnaire.

RESULTS

During both periods, 311 patients were included from vascular, trauma, orthopedic, urological, oncological, gastrointestinal, and ear-nose-throat and maxillary surgical units. Duration of preoperative fasting was prolonged in 290 (90.3%) patients for solid foods and in 208 (67.8%) patients for clear liquids. Median duration of preoperative fasting from solid foods and clear liquids was respectively 2.5 and 3 times the recommended 6 and 2 hours, with no improvements from one period to another. Postoperative food intake was resumed within 4 hours in 30.7% of the patients. Median duration of perioperative fasting was 23:46 hours (interquartile range 20:00-30:30 hours) for solid foods and 11:00 hours (interquartile range 7:53-16:00 hours) for clear liquids.

CONCLUSION

Old habits die hard. Despite 20 years of fasting guidelines, surgical patients are still exposed erroneously to prolonged fasting in 2 hospitals. Patients should be encouraged to eat and drink until 6 and 2 hours, respectively, before surgery and to restart eating after surgery.

Preoperative Fasting Guidelines: Where Are We Now? Findings From Current Practices in a Tertiary Hospital

PURPOSE

New evidence-based fasting guidelines have been published in recent years. However, while water and solid food fasting times before anesthesia are recommended to be 2 and 6 hours, respectively, these times are often longer in clinical practice. This study aimed to investigate the awareness and implementation of the fasting guideline recommendations among nurses and anesthesiologists, as well as evaluate the actual fasting durations in patients in a tertiary hospital.

DESIGN

A cross-sectional study was used.

METHODS

Questionnaires were designed to collect the knowledge of fasting time among registered anesthesiologists and nurses. Data on the instructed and actual fasting durations among patients scheduled for elective surgery were evaluated.

FINDINGS

Approximately half of the nurses indicated that solid food fasting durations were shorter than 6 hours or longer than 8 hours, and two-thirds indicated that clear fluid fasting durations were shorter than 2 hours or longer than 4 hours. However, in clinical practice, nurse-instructed fasting durations were longer than what they knew was optimal. The anesthesiologists also prescribed longer fasting durations than the minimum fasting duration recommended. The actual fasting durations of the patients were significantly longer than the nurse-instructed fasting durations for solid food (13.41 ± 2.64 vs 9.87 ± 2.20 hours, P < .001) and clear fluids (10.27 ± 3.67 vs 8.98 ± 2.90 hours, P < .001). The nurse-instructed durations were significantly longer than the anesthesiologist-instructed durations according to the statements of patients (9.87 ± 2.20 vs 9.00 ± 2.00 hours for solid food, P < .001; 8.98 ± 2.90 vs 6.15 ± 3.25 hours for clear fluids, P < .001).

CONCLUSIONS

Excessive fasting durations were observed among patients. Anesthesiologists and nurses must work together to ensure that updated fasting instructions are implemented in routine clinical practice.

Gastric Ultrasound Assessing Gastric Emptying of Preoperative Carbohydrate Drinks: A Randomized Controlled Noninferiority Study

BACKGROUND

Tools for the evaluation of gastric emptying have evolved over time. The purpose of this study was to show that the risk of pulmonary aspiration is not increased with carbohydrate drink, by demonstrating that the gastric antral cross-sectional area (CSA) of the NO-NPO group is either equivalent to or less than that of the NPO (nil per os) group.

METHODS

Sixty-four patients scheduled for elective laparoscopic benign gynecologic surgery were enrolled and randomly assigned to the NPO group (n = 32) or the NO-NPO group (n = 32). After having a regular meal until midnight before surgery, the NPO group fasted until surgery, while the NO-NPO group ingested 400 mL of a carbohydrate drink at midnight and freely up to 2 hours before anesthesia. The primary outcome was the gastric antral CSA by gastric ultrasound in right lateral decubitus position (RLDP). Noninferiority was defined as a mean difference of CSA <2.8 cm2. Secondary outcomes included CSA in supine position, gastric volume (GV), GV per weight (GV/kg), GV/kg >1.5 mL/kg, and Perlas grade.

RESULTS

CSA in RLDP was not different between the NPO group (6.25 ± 3.79 cm2) and the NO-NPO group (6.21 ± 2.48 cm2; P = .959). The mean difference of CSA in RLDP (NO-NPO group - NPO group) was 0.04 (95% confidence interval [CI], -1.56 to 1.64), which was within the noninferiority margin of 2.8 cm2. CSA was not different between the 2 groups (4.17 ± 2.34 cm2 in NPO group versus 4.28 ± 1.23 cm2 in NO-NPO group; P = .828). GV in NPO group (70 ± 56 mL) was not different from NO-NPO group (66 ± 36 mL; mean difference, 3.66; 95% CI, -20 to 27; P = .756). GV/kg in the NPO group (1.25 ± 1.00 mL/kg) was not different from the NO-NPO group (1.17 ± 0.67 mL/kg; P = .694). The incidence of GV/kg > 1.5 mL/kg was not different between NPO (31.3%) and NO-NPO group (21.9%; P = .768). The median (interquartile range) of the Perlas grade was 1 (0-1) in NPO group and 0.5 (0-1) in NO-NPO group (P = .871).

CONCLUSIONS

Preoperative carbohydrates ingested up to 2 hours before anesthesia do not delay gastric emptying compared to midnight fasting, as evaluated with gastric ultrasound.

An exploration of pre-operative fasting practices in adult patients having elective surgery

Background:

Patients fast routinely before elective surgery in order to reduce gastric volume and acidity. The standard fasting time is ‘nil by mouth’ from midnight before surgery. In recent years, new guidelines have recommended that patients remain nil by mouth from clear fluids for 2 hours and from solids for 6 hours. This literature review explored preoperative fasting practices in adult patients from an international perspective.

Methods:

A literature search was undertaken of databases, including CINAHL Plus, PubMed, Medline, the Cochrane Central Register of Controlled Trials, Science Direct, Sage Journals and Embase.

Results:

Anaesthetists were found to possess greater knowledge of reduced preoperative fasting than other health professionals including nurses.

Conclusion:

Actual fasting time was found to be relatively longer than prescribed fasting times.

Unexpectedly prolonged fasting and its consequences on elderly patients undergoing spinal anesthetics. A prospective observational study1

Purpose

To measure the preoperative fasting durations with respect to time of the day and its effect on vital parameters and electrocardiogram in elderly patients undergoing surgery under spinal anesthesia.

Methods

This study investigated 211 patients older than 60 years undergoing elective surgery under spinal anesthesia. Patients scheduled for surgery in morning hours (AM) and afternoon hours (PM) were compared. Patients fasting hours and repeated measurements of mean arterial pressure (MAP), heart rate (HR), peripheral oxygen saturation (Sp02) and the type and number of ischemic electrocardiogram (ECG) signs were recorded and compared [preoperative, zeroth, 2nd,5th,15th,30th minutes following spinal anesthesia(SA)].

Results

Mean fasting durations were 12±2.8 and 9.5±2.1 hours in AM group and 15.5±3.4 12.7±4.4 hours in PM group for foods and liquids respectively. ECG changes were significantly more frequent in PM group and body temperatures were significantly higher in AM group patients.

Conclusion

Our study has shown that fasting times in our population is far longer than recommended and fasting prolonged>15 hours is related to a transiently increased cardiac stress and mild hypothermia.

Fluid deficits during prolonged overnight fasting in young healthy adults

BACKGROUND

Overnight fasting is often prolonged before scheduled surgery, and the extent of perioperative fluid replacement may influence outcome. In clinical practice, basic requirements are estimated at 1.2-2.0 mL·kg^-1 ·h^-1 , but there is little contemporary clinical data on what deficits result from complete fasting. This prospective preclinical study was designed to determine total fluid loss during overnight fasting, prolonged during daytime.

METHODS

Twenty (10 female) healthy adult volunteers, aged 24 (range 21-46) years, fasted from 22:00 until 16:00, and had their body weight and urine output measured at predefined time intervals.

RESULTS

The median (interquartile range) fluid deficits were 0.82 (0.73-1.00) kg, corresponding to 1.26 (1.11-1.41) g·kg^-1 ·h^-1 for the initial overnight fasting period, 0.59 (0.40-0.70) kg and 0.99 (0.83-1.31) g·kg^-1 ·h^-1 for the consecutive daytime period, and 1.47 (1.27-1.64) kg and 1.19 (1.05-1.28) g·kg^-1 ·h^-1 for the total period of fasting. Urine output accounted for 52% of total weight loss and was 36% of the baseline hourly level during the last four-hour period of fasting.

CONCLUSIONS

Ten hours of overnight fasting in young adults induces fluid deficits at the lower limit of estimated intervals referred to in clinical practice, and hourly weight loss gradually decreases further during prolonged daytime fasting. These findings indicate that current routine procedures do slightly overestimate fluid deficits resulting from prolonged fasting in perioperative clinical practice.

Preoperative fasting: Assessment of the practices of Lebanese Anesthesiologists

Background:

Although new guidelines developed by the American Society of Anesthesiologists (ASA) recommend a liberalized preoperative nutrition, authorized clinical practice guidelines or recommendations have not yet been proposed by the Lebanese Society of Anesthesia (LSA).

Objective:

The purpose of this study was to examine Lebanese anesthesiologists’ preoperative fasting routines and determine their knowledge and acceptance of the ASA recommendations, their attitude toward liberalized fasting, and the factors favoring their nonadherence to the new recommendations.

Materials and Methods:

This study was conducted in university hospitals, affiliated hospitals, and nonuniversity hospitals located in different regions of Lebanon. The survey was approved by the local ethics committee. A written questionnaire was emailed to all anesthesiologist members of the LSA which was completed anonymously.

Results:

Out of the 294 anesthesiologists registered in the LSA and who read the email, 118 (40.1%) completed the questionnaire. Of respondents, 90% are aware of the latest ASA practice guidelines for preoperative fasting, and 78.7% claim to apply them in their practices; however, 75% of respondents still require adult patients to stop eating after midnight, and only 45% allow them to drink clear fluids up to 2 h preoperatively. One of the main reasons for not complying with the ASA guidelines was “to allow flexibility for changes in the operating schedule.”

Conclusion:

A long preoperative fasting period is still the common practice for Lebanese anesthesiologists. National guideline for preoperative fasting as liberal as that recommended by the ASA should be considered.

A prospective survey on knowledge, attitude and current practices of pre-operative fasting amongst anaesthesiologists: A nationwide survey

Background and Aims:

Pre-operative fasting is a routine practice to minimise the risk of pulmonary aspiration. The leading societies of anaesthesia have adopted more liberal fasting guidelines to avoid the adverse effect of prolonged fasting. This survey was conducted to assess the knowledge, attitude and current practice of fasting guidelines among Indian anaesthesiologists and to analyse the reasons for non-compliance of these guidelines.

Methods:

A questionnaire consisted of 11 questions was distributed via 'Survey Monkey' software to 621 anaesthesiologists who attended the annual conference of the Indian Society of Anaesthesiologists held in Ludhiana, in 2016. American Society of Anaesthesiologists (ASA) practice guidelines for fasting were the standard of assessment.

Results:

The response rate to the survey was 52%. Of the respondents, 69% described correctly the practice guidelines to pre-operative fasting. Only seven percent respondents were aware of the benefits of liberalised fasting. More than 2/3^rd of the respondents advised fasting as per ASA guidelines during pre-anaesthetic check-up (PAC). However, only about 50% respondents confirmed that these guidelines are actually followed in their institution. Not having control on scheduling of cases in operation theatre and poor knowledge of ward nurses and surgeons were the common reasons for non-compliance of these guidelines. Twenty four percent respondents did not use routinely any drug for aspiration prophylaxis.

Conclusion:

Majority of the respondents were aware of the ASA fasting guidelines. However, the implementation of the guidelines and knowledge regarding benefits of liberalised fasting is poor among respondents.

Pre-operative fluid bolus for improved haemodynamic stability during minor surgery: A prospectively randomized clinical trial

BACKGROUND

Haemodynamic instability during the induction of anaesthesia and surgery is common and may be related to hypovolaemia caused by pre-operative fasting or chronic diuretic therapy. The aim of our prospective, controlled, randomized study was to test the hypothesis that a predefined fluid bolus given prior to general anaesthesia for minor surgery would increase haemodynamic stability during anaesthetic induction.

METHODS

Two hundred and nineteen fairly healthy adult patients requiring minor surgery were enrolled. All received standard treatment, including a pulse contour analysing device for non-invasive measurement of cardiac index. Infusion therapy was started in all patients at induction. The intervention group (106 patients) was randomized to receive an additional fluid bolus of 8 mL/kg Ringer's acetate solution before the induction of anaesthesia. The primary endpoint was the incidence of haemodynamic instability, defined as a significant reduction of blood pressure or cardiac index during induction of anaesthesia.

RESULTS

The interventional group had a lesser incidence of haemodynamic instability during induction (41.5% vs 56.6%, P = .025). This group also had higher cardiac index, stroke volume index, systolic and mean blood pressure and a greater left ventricular end-diastolic area.

CONCLUSIONS

A fluid bolus prior to anaesthesia reduced the incidence of haemodynamic instability during induction of general anaesthesia. The total fluid volume was slightly greater in the intervention group compared to the control group (1370 ± 439 mL vs 1219 ± 483 mL, P = .007). We conclude that a defined fluid bolus can help stabilizing haemodynamics in patients undergoing general anaesthesia.

Fasting Or Starving? Measurement of Blood Ketone Levels in 100 Fasted Elective and Emergency Adult Surgical Patients at An Australian Tertiary Hospital

Prolonged fasting leads to a shift from carbohydrate to fat as the primary energy source, resulting in the production of ketones such as beta-hydroxybutyrate. Hyperketonaemia and ketoacidosis have been observed in young children fasting for surgery. The aim of this study was to investigate ketonaemia in adults fasted for surgery. One hundred non-diabetic adults presenting for elective or emergency surgery were assessed for the presence of hyperketonaemia (beta-hydroxybutyrate levels more than 1 mmol/l), and the relationship between beta-hydroxybutyrate, blood glucose and fasting duration was investigated. Three of 100 patients demonstrated hyperketonaemia, one of whom had ingested a ketogenic supplement the evening prior to surgery. No patient demonstrated beta-hydroxybutyrate levels suggestive of ketoacidosis (above 3 mmol/l). No relationship between fasting duration and ketone or glucose levels was observed. We found no evidence that prolonged preoperative fasting led to beta-hydroxybutyrate levels consistent with ketoacidosis.

Preoperative fasting for ambulatory cataract surgery: asystematic review

Given the lack of policy standardization in Canada, this systematic review investigates the optimal duration of preoperative fasting in cataract surgery. A literature search was conducted on Ovid MEDLINE, with potential articles screened by 2 independent authors. The primary endpoint was the incidence of aspiration. Overall, 231 articles were screened, of which 6 were eligible. Two studies found no cases of aspiration in over 35 000 patients who underwent cataract surgery without preoperative fasting, some with intravenous sedation (50% in 1 series, less than 1% in the second). A survey of the British Ophthalmic Anaesthesia Society found that over 50% of centres did not require fasting before cataract surgery. Only 1 included report discussed a case of aspiration pneumonitis following cataract surgery with general anaesthesia and 14hours of preoperative fasting. In closing, further evidence is needed to delineate the risk of pulmonary aspiration based on fasting time in cataract surgery.

Preoperative Fasting among Adult Patients for Elective Surgery in a Kenyan Referral Hospital

Background. Preoperative fasting (POF) is physiologically and precautionary important during anesthesia and surgery. POF from midnight has been practiced despite the recommended shorter practice. Objective. Assessing preoperative fasting among adult patients scheduled for elective surgery at Kenyatta National Hospital (KNH). Methods. A descriptive cross-sectional study involving 65 surgical patients. A questionnaire of mixed questions on demographics, reasons, source of instructions, opinion on instructions, time, premedication practices, outcome, and complains on NPO was used. Analysis was quantitatively done with SPSS v. 22. Ethical approval was obtained from KNH-UoN ERC. Results. Of the respondents 93.8% lacked knowledge on the correct reasons for POF and felt that the instructions were unclear and less important <50%. POF instructions were administered by nurses 80%, anesthetists 15%, and surgeons 5%. Most of respondents (73.8%) fasted > 15 hours. The POF outcomes were rated moderately challenging as follows: prolonged wait for surgery 44.6%, thirst 43.1%, hunger 36.9%, and anxiety 29.2%. Conclusion. Nurses are critical in providing POF instructions and care, and patient knowledge level is a mirror reflection of the quality of interventions. This underscores the need to build capacity for nurses and strengthen the health system to offer individualized preoperative interventions as well as monitoring and clinical auditing of fasting practices.

Reducing pre-operative fasting while preserving operating room scheduling flexibility: feasibility and impact on patient discomfort

BACKGROUND

The need to preserve operating room (OR) scheduling flexibility can challenge adherence to the 2-h pre-operative fasting period recommendation before elective surgery. Our primary objective was to assess the feasibility of a pre-operative carbohydrate (CHO) drink delivery strategy preserving OR scheduling flexibility.

METHODS

During the 1st study phase, patients admitted for elective surgery fasted overnight (Control group); during the 2nd phase, patients fasted overnight and received a pre-operative CHO drink (CHO group). CHO delivery time was set to allow any patient to be ready for surgery 30 min ahead of the scheduled time and any patient with an operation scheduled in the afternoon to be ready at 13:00 hours; patients admitted the morning of an early morning operation would not be allowed to take a CHO drink.

RESULTS

We included 194 patients in the Control group and 199 in the CHO group. In the CHO group, the morning CHO dose was delivered to 66.3% of the patients (95% CI 59.3-72.9%), with a median pre-operative fasting time period of 4 h 57 min. After excluding patients admitted the morning of an operation scheduled before 10:00 hours, the delivery rate was 77.2% (70.2-83.3%). Patients in the CHO group experienced significantly less pre-operative thirst (median 2 vs. 5 on a 0-10 scale, P < 0.0001) and hunger (0 vs. 2, P < 0.0001) than those in the Control group.

CONCLUSION

Although preservation of OR scheduling flexibility resulted in a longer fasting time than recommended, CHO drink can be made available to a large proportion of patients with significantly reduced perioperative discomfort.

Randomized Controlled Trial Assessing the Feasibility of Shortened Fasts in Intubated ICU Patients Undergoing Tracheotomy

Objective

American Society of Anesthesiology guidelines recommend preoperative fasts of 6 hours after light snacks and 8 hours after large meals. These guidelines were designed for healthy patients undergoing elective procedures but are often applied to intubated intensive care unit (ICU) patients. ICU patients undergoing routine procedures may be subjected to unnecessary prolonged fasts. This study tests whether shorter fasts allow for better nutrition delivery and patient outcomes without increasing the risk.

Study Design

Randomized blinded controlled trial.

Setting

Tertiary academic medical center.

Subjects

ICU patients undergoing bedside tracheotomy.

Methods

Intubated ICU patients who were receiving enteral feeding and for whom bedside tracheotomy was indicated were enrolled prospectively and randomly allocated to 2 parallel preoperative fasting regimens: a 6-hour fast (control) and a 45-minute fast (intervention). Patients were assessed for aspiration, caloric delivery, metabolic markers, and infectious and noninfectious complications.

Results

Twenty-four patients were enrolled and randomized. There were no complications related to the procedure. There were no cases of intraoperative aspiration identified. There was a single postoperative pneumonia in the control group. Median (interquartile range) length of fast and caloric delivery were significantly different between the control group and the shortened fast group: 22 hours (18, 34) vs 14 hours (5, 25; P < .001) and 429 kcal (57, 1125) vs 1050 kcal (825, 1410; P = .01), respectively.

Conclusions

Shortening preoperative fasts in intubated ICU patients allowed for better caloric delivery in the preoperative period.

Frequency and Appropriateness of Fasting Orders in the Hospital

OBJECTIVE

To evaluate the frequency and appropriateness of nil per os (nothing by mouth) (NPO) orders and determine the number of meals missed because of these orders among hospitalized patients.

PATIENTS AND METHODS

We retrospectively analyzed inpatient NPO orders at an academic institution in the United States. The frequency and duration of NPO orders and the number of meals missed because of these orders were assessed for adult patients admitted to the hospital medicine services from January 1, 2013, through December 31, 2013, with a hospital stay of 2 or more and 30 or fewer days. Two blinded reviewers assessed if the order could be avoided or the period shortened for a random sample of NPO orders of 120 or more minutes' duration that were written for patients on the general medicine ward.

RESULTS

A total of 3641 NPO orders were identified. At least one NPO order was placed in 46.6% of the admissions (2211 of 4743). The median duration of NPO orders was 12.8 hours (interquartile range, 9.2-17.3 hours), resulting in 2 (interquartile range, 1-4) missed meals. Of 1130 NPO orders reviewed, 263 (23.3%; 95% CI, 20.9%-25.8%) were deemed avoidable (κ statistic, 0.68), and 482 (42.7%) were unavoidable but led to more missed meals than needed. Taken together, patients could have had 44.8% of the meals (1085 of 2424; 95% CI, 42.8%-46.7%) missed due to NPO orders.

CONCLUSION

Approximately half of the patients admitted to the hospital medicine services experienced a period of fasting. One in 4 NPO orders and nearly half of missed meals could have been avoided. Further study is warranted to assess the generalizability of our findings.

Improved patient education facilitates adherence to preoperative fasting guidelines

Preoperative fasting is recognised as an important factor in perioperative patient care. Implementation of guidelines on preoperative fasting remains sub-optimal. We audited perioperative fasting in a district general hospital, implemented changes to the preoperative information leaflet and improved fasting practices. The manner in which information is presented to patients impacts behavior and adherence to recommendations. Improving this domain of clinical practice requires thorough and conscious effort and repeated reassessment.

[Preoperative fasting guidelines: an update]

Anesthesiology societies have issued various guidelines on preoperative fasting since 1990, not only to decrease the incidence of lung aspiration and anesthetic morbidity, but also to increase patient comfort prior to anesthesia. Some of these societies have been updating their guidelines, as such that, since 2010, we now have 2 evidence-based preoperative fasting guidelines available. In this article, an attempt is made to review these updated guidelines, as well as the current instructions for more controversial patients such as infants, the obese, and a particular type of ophthalmic surgery.

Preoperative oral rehydration solution intake volume does not affect relative change of mean arterial blood pressure and crystalloid redistribution during general anesthesia in low-risk patients: an observational cohort study

Despite the implementation of liberal preoperative fasting routines, it is unclear whether preoperative oral rehydration solution intake volume affects blood pressure during general anesthesia. We enrolled 60 patients (American Society of Anesthesiologists status I/II) undergoing tympanoplasty. Patients drank 200-1,000 ml oral rehydration solution until 2-3 h before anesthesia induction. Anesthesia was induced by propofol and maintained with sevoflurane and remifentanil. Coinciding with anesthesia induction, 15 ml/kg Ringer's acetate solution was administered intravenously over 60 min followed by 1 ml/kg Ringer's acetate solution over the next 30 min. Mean arterial blood pressure (MAP) and whole-body bioelectrical resistance for extracellular fluid (R e) during anesthesia were compared between retrospectively classified intake groups of oral rehydration solution. There were no differences in mean MAP during the 30-90 min period relative to baseline [0.67 (0.60-0.74), 0.65 (0.61-0.76), 0.64 (0.60-0.70), P = 0.96] and relative R e at 90 min [0.945 (0.018), 0.944 (0.021), 0.943 (0.021), P = 0.95] between the small (n = 14), intermediate (n = 29), and large (n = 17) intake groups. The intake volume of preoperative oral rehydration solution does not affect the magnitude of hypotension during general anesthesia in low-risk patients undergoing minor surgery.

Parents' understanding of and compliance with fasting instruction for pediatric day case surgery

OBJECTIVE

To determine whether parents understand and adhere to preoperative fasting instructions.

AIM

To identify how we may reduce perioperative morbidity relating to failure to fast.

BACKGROUND

Children are routinely fasted preoperatively with the aim of reducing the risk of aspiration of gastric contents and its sequelae.

METHODS

Parents of children on the day case ward following elective surgery completed a survey asking: (i) For how long was your child asked to fast? (ii) How long did you ensure your child was fasted of food and clear fluids? (iii) What do you think is the purpose of fasting? We also asked the parents to complete a checklist of items they thought acceptable to consume when fasting.

RESULTS

Despite affirming fasting status in the preoperative check, 13.5% were not fasted. Parents reported advised fasting times of 1-24 h (median 6) for solids and 0.5-24 h (median 3) for fluids. Children were fasted of solids for 3-40 h (median 9.5) and of fluids for 0.5-24 h (median 5). Regarding the understanding of fasting, 9 referred to aspiration and 53 to the prevention of nausea or vomiting. Thirteen believed that fasting status altered the efficacy of anesthesia. During the fasting period, 4.9% would allow French fries, 22.3% toast/crackers, 17.5% cereal, 14.7% a sweet, 14.9% gum, and 12.6% tea with milk.

CONCLUSIONS

Children we believe to be fasted may not be. Parents may deliberately misrepresent the actual fasting status of their child. Adherence to fasting advice may be affected by parents' recall and understanding of fasting advice.

Hydration status after overnight fasting as measured by urine osmolality does not alter the magnitude of hypotension during general anesthesia in low risk patients

BACKGROUND

The increased distribution of crystalloid solution into the interstitial space may decrease the effectiveness of intravascular volume loading in patients. We investigated whether preoperative hydration status after overnight fasting affects interstitial fluid redistribution and thus the magnitude of hypotension during general anesthesia.

METHODS

Sixty ASA physical status I/II patients undergoing tympanoplasty fasted from midnight. Anesthesia was induced by fentanyl and propofol and maintained with sevoflurane and remifentanil. Coinciding with the induction of anesthesia, 15 mL/kg acetated Ringer solution was infused IV over 60 minutes followed by 1 mL/kg acetated Ringer solution over the next 30 minutes. Urine osmolalities after induction of anesthesia and during the study period (pre-U(osm), post-U(osm)) and percent decreases of whole-body bioelectrical resistance for extracellular fluid relative to baseline at the end of the study period (ΔR(e)) were measured. Patients with a pre-U(osm) < the 25th percentile or with a pre-U(osm) > the 75th percentile of pre-U(osm) were categorized in the hydrated or the dehydrated group, respectively. A range of variables, including mean arterial blood pressure during the 30- to 90-minute period relative to baseline, and ΔR(e), were compared between the groups.

RESULTS

The dehydrated group (pre-U(osm) >759.5 mOsm/kg, n = 15) had a lower age (44 vs 52 years, P = 0.049) and had a higher post-U(osm) (181 vs 55 mOsm/kg, P = 0.001) compared with the hydrated group (pre-U(osm) <378.5 mOsm/kg, n = 15). Mean arterial blood pressure during the 30- to 90-minute period relative to baseline (0.67 vs 0.67, P = 0.85) with 95% confidence interval for the difference of means (-0.070 to 0.084) and ΔR(e) (5.6% vs 6.0%, P = 0.58) with 95% confidence interval for the difference of means (-1.85% to 1.06%) were similar for the hydrated and dehydrated groups.

CONCLUSIONS

Preoperative dehydration after overnight fasting as measured by urine osmolality did not alter the magnitude of hypotension during general anesthesia. This finding suggests that intravascular volume loading with crystalloid solution to prevent hypotension during general anesthesia is an unfounded practice for low risk patients after overnight fasting.