Nulla Per Os (NPO) guidelines: time to revisit?

International consensus on fasting terminology

Although fasting is increasingly applied for disease prevention and treatment, consensus on terminology is lacking. Using Delphi methodology, an international, multidisciplinary panel of researchers and clinicians standardized definitions of various fasting approaches in humans. Five online surveys and a live online conference were conducted with 38 experts, 25 of whom completed all 5 surveys. Consensus was achieved for the following terms: "fasting" (voluntary abstinence from some or all foods or foods and beverages), "modified fasting" (restriction of energy intake to max. 25% of energy needs), "fluid-only fasting," "alternate-day fasting," "short-term fasting" (lasting 2-3 days), "prolonged fasting" (≥4 consecutive days), and "religious fasting." "Intermittent fasting" (repetitive fasting periods lasting ≤48 h), "time-restricted eating," and "fasting-mimicking diet" were discussed most. This study provides expert recommendations on fasting terminology for future research and clinical applications, facilitating communication and cross-referencing in the field.

Liberal Preoperative Fasting in Adults Undergoing Elective Surgery: A Scoping Review Protocol

Background

Prolonged fasting before surgery has negative effects on the physiology and psychology of patients. Preoperative liberal fasting proposes that patients can drink clear liquids before entering the operating theater, challenging the guideline strategy of a two-hour preoperative liquid fast for adults. In recent years, there have been an increasing number of studies on liberal preoperative fasting in adults. However, currently there is no consensus on the safe amount of fluid consumed, adverse effects, or benefits of this new policy.

Objective

This scoping review protocol will map the existing evidence of liberal preoperative fasting in adults undergoing elective surgery for clinical practice, to summarize more scientific evidence to healthcare professionals when providing perioperative care. Methods and Analysis. The methodology will follow the six steps of the Arksey and O'Malley methodological framework and be guided by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Review. A comprehensive search of six databases will be performed from their inception to 31 May 2023 to identify suitable English studies. Two trained investigators will independently screen and extract the data, and any disagreements will be judged by a third investigator. The results of the study will be presented as graphs or tables. Ethics and Dissemination. This scoping review only examines literature in the database, without reference to human or animal studies, and therefore does not require ethical approval. The findings of this scoping review will be published in peer-reviewed journals or presented at conferences. The Registration Number. This scoping review has been registered in the Open Science Framework (https://doi.org/10.17605/OSF.IO/PMW7C).

Morning or Afternoon Scheduling for Elective Coronary Artery Bypass Surgery: Influence of Longer Fasting Periods from Metabolic and Hemodynamic Perspectives

BACKGROUND

Prolonged preoperative fasting may worsen postoperative outcomes. Cardiac surgery has higher perioperative risk, and longer fasting periods may be not well-tolerated. We analysed the postoperative metabolic and hemodynamic variables in patients undergoing elective coronary artery bypass grafting (CABG) according to their morning or afternoon schedule.

METHODS

Single-centre retrospective study at University teaching hospital (1-year data collection from electronic medical records). Using a mixed-effects linear regression model adjusted for several covariates, we compared metabolic (lactatemia, pH, and base deficit [BD]) and haemodynamic values (patients on vasoactive support, and vasoactive inotropic score [VIS]) at 7 prespecified time-points (admission to intensive care, and 1st, 3rd, 6th, 12th, 18th, and 24th postoperative hours).

RESULTS

339 patients (n = 176 morning, n = 163 afternoon) were included. Arterial lactatemia and BD were similar (overall P = 0.11 and P = 0.84, respectively), while pH was significantly lower in the morning group (overall P < 0.05; mean difference -0.01). Postoperative urine output, fluid balance, mean arterial pressure, and central venous pressure were similar (P = 0.59, P = 0.96, P = 0.58 and P = 0.53, respectively). A subgroup analysis of patients with diabetes (n = 54 morning, n = 45 afternoon) confirmed the same findings. The VIS values and the proportion of patients on vasoactive support was higher in the morning cases at the 18th (P = 0.002 and p=0.04, respectively) and 24th postoperative hours (P = 0.003 and P = 0.04, respectively). Mean intensive care length of stay was 1.94 ± 1.36 days versus 2.48 ± 2.72 days for the afternoon and morning cases, respectively (P = 0.02).

CONCLUSIONS

Patients undergoing elective CABG showed similar or better metabolic and hemodynamic profiles when scheduled for afternoon surgery.

Preoperative clear fluids fasting times in children: retrospective analysis of actual times and complications after the implementation of 1-h clear fasting

BACKGROUND

Preoperative fasting before elective pediatric surgery is a matter of ongoing debate. The objectives of this study were to evaluate the compliance to a recently implemented preoperative fasting protocol (clear fluids until 1 hour from the induction of anesthesia), to identify predictors of prolonged preoperative fasting time, and to determine whether duration of preoperative fasting was associated with adverse outcomes.

METHODS

Retrospective single-center study in an operating theater of a tertiary pediatric hospital.

RESULTS

In a 6-month period, 1820 consecutive patients were analyzed. The data collected in the questionnaire reporting the time of last food, milk and/or liquid intake, and eventual reasons for nonadherence was analyzed. Median (interquartile range) preoperative fasting time was 186 (110-345) min. In 502 patients (27.6%), duration of preoperative fasting to clear fluid ranged from 60 to 119 min, whereas in 616 (34%) it was 120-240 min. The reasons for not respecting fasting time rules are mostly related to communication issues or unwillingness by the patients. A significant difference in fasting times was evident between infants and children older than 10 years (188, 105-290 vs. 198, 115-362; p = 0.02). Fasting times were significantly shorter in the inpatient group and in the first scheduled patients of the morning. Clear fluids fasting times were significantly longer in patients with hypovolemia complications than in those without, 373 (185-685) vs. 180 (110-330) min (p < 0.0001). Longer fasting times to clear fluids, younger age, and scheduled surgery time were independently associated with the odds of experiencing complications.

CONCLUSIONS

In this single pediatric center study, median clear fluids fasting time was three times higher (180 min) than those recommended by the preoperative fasting protocol. Compliance to the protocol was observed in approximately 1 out of 4 patients (27.6%). Longer fasting times were associated with an increased risk of complications, which might be due to dehydration and/or hypovolemia.

Rapid Evaluation of Gastric Content With Ultrasound: An Educational Tool

Pulmonary aspiration is a severe complication in patients receiving anesthesia for surgical procedures. The risk and severity of aspiration are significantly higher in the presence of substantial gastric contents. Bedside ultrasound imaging of the gastric antrum is emerging as a rapid and valuable method to evaluate gastric contents before surgery. Rapid gastric ultrasound using a three-category grading system promotes timely decision-making to help in emergent or urgent surgeries by identifying patients with potentially high gastric volumes or solid food contents. In emergent cases with limited time, a single ultrasound view of the gastric antrum is still likely to yield helpful information. In this report, we argue that bedside ultrasound offers a more reliable assessment of gastric contents than assumptions based on time-based fasting guidelines.

Reducing Preoperative Fasting Through Technology and Education in an Acute General Surgical Adult Cohort

BACKGROUND

Despite widespread support for reduced fasting protocols prior to anesthesia, the traditional "fast from midnight" (FFMN) remains widely employed. This study implemented a pilot preoperative fasting reduction program for patients booked for acute surgery in the Department of General Surgery at a busy metropolitan tertiary hospital, including use of an electronic health record (EHR)-based solution, aiming to measure effect on fasting times and use of intravenous fluid (IVF).

METHODS

A pilot program was implemented in August 2021 in the Emergency General Surgery (EGS) unit at the Royal Melbourne Hospital, Australia. This included a new smart phrase within the EHR (EU2WU6: Eat until 2, drink water until 6) and an education campaign. Adult patients who underwent preoperative fasting between September 1 and December 31, 2021, were screened. Uptake of the protocol was recorded. Further, total fasting times (TFT) and IVF use were recorded. Potential impact with varying levels of protocol uptake was modeled.

RESULTS

Uptake of EU2WU6 increased from 0% to 80%. TFT and total time on IVF (TT-IVF) were lower using EU2WU6 (TFT 7 hours vs. 13 hours, p < 0.001; TT-IVF 3 hours vs. 8 hours, p < 0.001). Proportion of patients requiring fluid overnight when using EU2WU6 was lower (18/45 vs. 34/50, p = 0.0062). Hospitalwide yearly savings, with 100% application of EU2WU6, were projected at 2,050 bags of IVF (at a cost savings of A$2,296), 10,251 minutes for physicians, and 20,502 minutes for nurses.

CONCLUSION

The pilot preoperative fasting reduction program successfully reduced disparity between evidence and clinical practice.

Reducing the use of nil per os past midnight for inpatient diagnostic and therapeutic procedures: A quality improvement initiative

BACKGROUND

Pre-procedural fasting (nil per os [NPO]) is a commonly implemented protocol to prevent aspiration during certain diagnostic and therapeutic procedures. However, evidence suggests aspiration risk is quite low. Current guidelines support a reduced fasting duration before procedures necessitating anesthesia or sedation, but many health systems persist in the use of NPO past midnight.

OBJECTIVE

We aimed to reduce the use of NPO p MN before inpatient diagnostic and therapeutic procedures necessitating anesthesia or sedation by 50% within 6 months.

DESIGN, SETTING AND PARTICIPANTS

We performed a quality improvement initiative at a single academic health system in Southeast Texas. We include the experience of patients of all ages across 4 affiliated hospitals (one main academic hospital and three community satellite hospitals).

INTERVENTION

An interprofessional team was convened to review best practices and oversee this quality improvement initiative. Diagnostic imaging protocols previously requiring NPO were amended to reflect evidence-based fasting requirements. A pre-procedure clear liquid diet was also implemented.

MAIN OUTCOME AND MEASURES

We describe the steps to implementation, feasibility of implementation as described through key process measures, and the safety of implementation (balancing measures).

RESULTS

NPO requirements were removed from 70% of existing diagnostic imaging and therapeutic orders. After these amended protocols and the implementation of a pre-procedure clear liquid diet, we displayed an immediate 50% reduction in NPO past midnight usage. Further stakeholder engagement/education and targeted interventions reduced NPO past midnight usage to only 33% of pre-procedural diet orders. Surgery remains the most common indication for continued use of NPO. Aspiration events and procedural delays were rare.

Association of a Liberal Fasting Policy of Clear Fluids Before Surgery With Fasting Duration and Patient Well-being and Safety

Importance

Current fasting guidelines for procedures under anesthesia are poorly implemented, leading to negative metabolic sequelae. Recent studies in children showed support of liberal clear fluid intake; adult physiology can support clear fluid intake, but implementation studies are lacking.

Objective

To evaluate the successfulness of implementation of a liberal clear fluid policy with regard to fasting duration, well-being, and safety in adults scheduled for anesthesia.

Design, Setting, and Participants

This was a quality improvement study conducted from January 2016 to July 2021 at a tertiary referral hospital in the Netherlands. Adults scheduled for nonemergency procedures under anesthesia were included in the study. Patients undergoing obstetrics procedures or those who were intubated preoperatively were excluded.

Interventions

Stepwise introduction of a liberal fluid fasting policy, allowing for ingestion of clear fluids until arrival at the operating room.

Main Outcomes and Measures

The primary outcome was change in fasting duration. Secondary outcomes were patient well-being, measured as preoperative thirst, amount of fluid ingested, postoperative nausea and vomiting (PONV), and administration of antiemetics. Safety was measured as incidence of regurgitation and aspiration (pneumonia).

Results

Of the 76 451 patients (mean [SD] age, 56 [17] years; 39 530 male individuals [52%] 36 921) included in the study, 59 036 (78%) followed the standard policy, and 16 815 (22%) followed the liberal policy. Time series analysis showed an estimated fasting duration decrease of 3:07 hours (IQR, 1:36-7:22; P < .001) after implementation of the liberal policy. Postimplementation median (IQR) fasting duration was 1:20 (0:48-2:24) hours. The incidence of regurgitation changed from 18 (95% CI, 14-21) to 24 (95% CI, 17-32) in 10 000 patients, and the incidence of aspiration changed from 1.7 (95% CI, 0.6-2.7) to 2.4 (95% CI, 0.5-4.7) in 10 000 patients. In the liberal policy, thirst feelings decreased (37% [4982 of 8615] vs 46% [3373 of 7362]; P < .001). PONV incidence decreased from 10.6% (6339 of 59 636) to 9.4% (1587 of 16 815; P < .001) and antiemetic administration decreased from 11.0% (6538 of 59 636) to 9.5% (1592 of 16 815; P < .001).

Conclusions and Relevance

Results of this quality improvement study suggest that a liberal fasting policy was associated with a clinically relevant reduction in fasting duration and improved patient well-being with regard to preoperative thirst and PONV. Although a slightly higher incidence of regurgitation could not be ruled out, wider implementation of such a policy may be advocated as results are still within the clinically accepted risks margins. Results suggest that surgical procedures in patients who drink clear fluids within 2 hours before anticipated anesthesia should not be postponed or canceled.

The association between implementation of multidisciplinary rounds and clinical outcomes

BACKGROUND

Multidisciplinary rounds (MDR) consisting of social workers, dietitians, pharmacists, physical therapists, nurses, and physicians have been implemented at many healthcare institutions to address the complex components of inpatient care. However, little is known on the association of MDR on clinical outcomes across cardiovascular pathologies. This study aimed to investigate the impact of MDR on cardiovascular patients.

METHODS

Hospital admissions to inpatient cardiology were evaluated prior to (November 2017 to November 2018) and after implementation of MDR (December 2018 to August 2020) at a metropolitan academic medical center. The following outcomes were evaluated: clinical complications (incidence of stroke, gastrointestinal bleed, myocardial infarction, or systemic infection during hospitalization), Length of Stay (LOS), 30-day readmissions and all-cause in-hospital mortality. Secondary outcomes included utilization of physical therapy and dietary services.

RESULTS

Admissions were evaluated prior to (N = 1054) and after (N = 1659) MDR implementation. All-cause in-hospital mortality after MDR implementation decreased significantly from 2.8 to 1.6% (P = 0.03). Although the number of complications and LOS decreased, these differences were not statistically significant. No significant change was observed in 30-day readmissions. Significant increase in the utilization of physical therapy (34.2 to 53.5%; P < 0.01) and dietary services (7.2 to 19.3%; P < 0.01) were observed.

CONCLUSION

Multidisciplinary rounds implementation was associated with significantly decreased mortality and positively impacted resource utilization with increased consultations for ancillary services. MDR is a high impact intervention that utilizes existing resources to improve mortality and should be implemented especially for cardiovascular patients. Further investigation into the benefit of MDR across different patient populations and care settings is warranted.

The Effects of Intravenous Vitamin C on Stress Response Severity in Abdominal Hysterectomy Following Prolonged Fasting Time

Background

Inevitable prolonged fasting time before surgery leads to inflammatory reactions, surgery-related stress response, and consequently unfavorable outcomes; thus, developing strategies to mitigate these consequences is crucial.

Objectives

In this study, we evaluated the effect of ascorbic acid on stress response reduction in abdominal hysterectomy following prolonged fasting time.

Methods

Eligible women candidates for abdominal hysterectomy following prolonged fasting time were enrolled in the study and divided into 2 groups of vitamin C [group C; 1 g intravenously (IV) before surgery] and placebo (group P). Before induction of anesthesia, C-reactive protein (CRP), mean arterial pressure (MAP), heart rate (HR), and blood sugar (BS) were measured and compared between the 2 groups at 4-point times, 24 and 48 hours immediately after extubation.

Results

Finally, the data of 80 patients were included for the final analysis. A statistically significant difference was observed between the 2 groups in terms of CRP and BS values in T1 CRP serum levels; at the end of the study, CRP values were 0.5 ± 0.55 and 0.92 ± 0.69 in groups C and P, respectively (P = 0.012), and BS levels were 124.12 ± 18.11 and 152.0 ± 17.36 in groups C and P, respectively (P = 0.0001). However, this significant difference was not observed at T2 regarding CRP (P = 0.145) and BS (P = 0.135), as well as at T3 regarding CRP (P = 0.282) and BS (P = 0.213). However, according to both CRP and BS values, the trend of changes from T0 to T3 was significant in the 2 groups (P < 0.0001). Hemodynamic parameters were not significantly different between the 2 groups. No adverse event was reported in the 2 groups.

Conclusions

We found that ascorbic acid could induce short-term positive effects in abdominal hysterectomy following prolonged fasting time. Obviously, the optimal dosage, timing, and specific cases that benefit the most from this intervention should be investigated.

Quality-improvement project to reduce actual fasting times for fluids and solids before induction of anaesthesia

Background

Despite well-defined recommendations, prolonged fasting times for clear fluids and solids are still common before elective surgery in adults. Extended fasting times may lead to discomfort, thirst, hunger and physiological dysfunctions. Previous studies have shown that prolonged fasting times are frequently caused by patients being misinformed as well as inadequate implementation of the current guidelines by medical staff.

This study aimed to explore how long elective surgery patients fast in a German secondary care hospital before and after the introduction of an educational note for patients and re-training for the medical staff.

Methods

A total of 1002 patients were enrolled in this prospective, non-randomised interventional study. According to the power calculation, in the first part of the study actual fasting times for clear fluids and solids were documented in 502 consecutive patients, verbally instructed as usual regarding the recommended fasting times for clear fluids (2 h) and solids (6 h). Subsequently, we implemented additionally to the verbal instruction a written educational note for the patients, including the recommended fasting times. Furthermore, the medical staff was re-trained regarding the fasting times using emails, newsletters and employee meetings. Thereafter, another 500 patients were included in the study.

We hypothesised, that after these quality improvement procedures, actual fasting times for clear fluids and solids would be more accurate on time.

Results

Actual fasting times for clear fluids were in the median 11.3 (interquartile range 6.8–14.3; range 1.5–25.5) h pre-intervention, and were significantly reduced to 5.0 (3.0–7.2; 1.5–19.8) h after the intervention (median difference (95%CI) − 5.5 (− 6.0 to − 5.0) h). The actual fasting times for solids also decreased significantly, but only from 14.5 (12.1–17.2; 5.4–48.0) h to 14.0 (12.0–16.3; 5.4–32.0) h after the interventions (median difference (95%CI) − 0.52 (− 1.0 to − 0.07) h).

Conclusions

The study showed considerably extended actual fasting times in elective adult surgical patients, which were significantly reduced by simple educational/training interventions. However, the actual fasting times still remained considerably longer than defined in recommended guidelines, meaning further process optimisations like obligatory fluid intake in the early morning are necessary to improve patient comfort and safety in future.

Trial registration

German registry of clinical studies (DRKS-ID: DRKS 00020530, retrospectively registered).

[Preoperative fluid fasting : Establishment of a liberal fluid regimen using fasting cards]

BACKGROUND

Preoperative fasting times for clear liquids surpass by far the recommendations of the specialist societies. The aim of this study was to introduce a liberal regimen for preoperative fasting of clear liquids using fasting cards as a training tool and to evaluate the implementation.

MATERIAL AND METHODS

We developed a liberalized regimen of preoperative clear fluid fasting times, which allows patients to drink water, apple juice, tea and coffee until being called to the operating theatre. Each patient receives a bed-side fasting card with written information specifying fasting times for solid food and liquids. Patients who are allowed to drink water, apple juice, tea and coffee until the call to the operating theatre receive a blue fasting card. Patients with coexisting diseases or conditions that can affect gastric emptying or who need longer fasting times because of the surgical procedure get a yellow fasting card on which fasting times for fluids and solids can be documented individually. Patients who need to be nil per os (for example patients with ileus or bowel obstruction, emergency care) receive a red fasting card. On the back of the card the information is written in English, Turkish, Russian and Arabic. After a period of 8 months all surgical ward managers were asked to complete a questionnaire to assess the implementation of the new fasting regimen.

RESULTS

The response rate of the questionnaire was 100%. Without exception all interviewees would recommend the use of our liberalized fasting regimen. Almost all would also support the implementation of fasting cards. Out of 11 wards 9 found that patients were more relaxed and asked for intravenous fluids less often while waiting for surgery. The multilingual nature of the cards makes it easier to deal with patients who do not speak German. All ward managers consistently approved the new regimen in the event they themselves would need an operation. In order to make the fasting cards also usable in the future for rescue centers and functional units, such as endoscopy, echo or cardiac catheters, the reasons for fasting on the blue and yellow cards have been extended to operation or examination and on the red card to illness, operation or upcoming examination.

CONCLUSION

Patients should be allowed to drink water and hypotonic clear fluids until shortly before an operation to avoid complications of overly long fasting times. Fasting cards help to implement this by providing easy to understand information for patients and healthcare workers. This concept should be clearly structured, transparent for everyone, written down and brought to the attention of the patient without a language barrier.