|Year : 2018 | Volume
| Issue : 2 | Page : 105-109
Preoperative fasting in the day care patient population at a tertiary care, teaching institute: A prospective, cross-sectional study
Merlin Shalini Ruth1, MS Josephine2, Aparna Williams1
1 Department of Anesthesiology, Christian Medical College, Vellore, Tamil Nadu, India
2 Department of Nursing Services, Christian Medical College, Vellore, Tamil Nadu, India
|Date of Web Publication||9-Apr-2018|
Department of Anesthesiology, Christian Medical College, Vellore - 632 004, Tamil Nadu
Source of Support: None, Conflict of Interest: None
Context: Patients are fasting for inappropriately long duration preoperatively despite the American Society of Anesthesiologists (ASA) recommendations for liberal fasting guidelines. There is paucity of data on preoperative fasting duration in the day care patient population from India; hence, we studied the preoperative fasting status in the day care patient population. Aims: This study aims to study the preoperative fasting duration for solids and clear fluids and to compare the fasting times in the patients posted for the morning slot and the afternoon slot. Settings and Design: This was a prospective, observational, cross-sectional study at a tertiary care, teaching institute. Subjects and Methods: All Consenting adults, ASA grade 1 or 2, of either gender, presenting for day care surgery were included in the study. Data collected included the demographic profile, duration of fasting for solids, and clear fluids. The patients rated their hunger and thirst on a ten point numeric rating scale. We compared the fasting durations for solids and clear fluids in the patients presenting for the morning slot and afternoon slot for surgery. Statistical Analysis Used: T-test was used for analysis of continuous data with normal distribution and Mann–Whitney U-test for data with nonnormal distribution. Chi-square test was performed for categorical variables. Differences were considered significant at P < 0.05. Results: The mean duration of preoperative fasting for solids was 12.58 ± 2.70 h and for clear fluids was 9.02 ± 3.73 h. The mean fasting duration for solids in the patients presenting for the afternoon slot was significantly longer (P < 0.0001) than those presenting for the morning slot. The mean preoperative fasting duration for clear fluids was comparable among these patient groups (P = 0.0741). Conclusions: Patients are following inappropriately prolonged fasting routines, and there is a need to enforce liberal preoperative fasting guidelines to improve patient care.
Keywords: Day care surgery, hunger, preoperative fasting, thirst
|How to cite this article:|
Ruth MS, Josephine M S, Williams A. Preoperative fasting in the day care patient population at a tertiary care, teaching institute: A prospective, cross-sectional study. CHRISMED J Health Res 2018;5:105-9
|How to cite this URL:|
Ruth MS, Josephine M S, Williams A. Preoperative fasting in the day care patient population at a tertiary care, teaching institute: A prospective, cross-sectional study. CHRISMED J Health Res [serial online] 2018 [cited 2018 Dec 16];5:105-9. Available from: http://www.cjhr.org/text.asp?2018/5/2/105/229583
| Introduction|| |
Prolonged preoperative fasting is associated with numerous deleterious effects including dehydration, hypoglycemia, electrolyte imbalance, dizziness, increased postoperative nausea and vomiting, and inappropriate stress response to surgery. Multiple anesthesia guidelines from various anesthesia associations have reviewed the preoperative fasting recommendations to reduce prolonged preoperative fasting. Although the guidelines recommend that preoperative fasting for solids and nonhuman milk should be 6 h and for clear fluids should be two hours, the actual fasting times of patients are far from these recommendations. This study was designed to evaluate the preoperative fasting times for solids and clear fluids and to assess the hunger and thirst levels in adults undergoing elective day care surgery at a tertiary care, teaching institute.
| Subjects and Methods|| |
This prospective, cross-sectional, observational study at a tertiary care, teaching institute was conducted for a period of 3 months (January 1, 2017–March 31, 2017). The study was approved by the institutional review board and ethics committee (IRB no.:10908). The study included all consenting adult patients, of either gender, American Society of Anesthesiologists (ASA) class 1 or 2 posted for elective surgical procedures in the day care operation rooms. Exclusion criteria included patients aged >70 years and <18 years, ASA physical status 3 and above, patients undergoing emergency surgery, those who were on parenteral or enteral nutrition, or who were receiving intravenous fluids preoperatively. Patients undergoing gynecological and gastrointestinal or obstetric surgery were excluded as these patients undergo their day care surgery in a different set of operation rooms in our institute. During the period January 1 to March 31, 2017; 370 patients were found eligible for recruitment to our study, out of which 330 patients consented. Among them, 226 patients underwent surgery in the morning slot and 104 patients in the afternoon slot.
All patients were given fasting instructions by the nursing staff, according to the ASA guidelines  on their preoperative visit a day before the surgical procedure. A semi-structured questionnaire was administered by a dedicated staff nurse to collect the patient data on the day of surgery. The questionnaire included the sociodemographic profile of the study participants and the data related to the preoperative fasting periods. Patients were asked to indicate the time of last ingestion of solids and clear fluids by two investigators at different time points, initially as they were admitted to the day care facility and about 30 min later before induction of anesthesia. They were also asked to indicate the level of their preoperative anxiety on the numeric rating scale (NRS) ranging from 0 to 9.
The primary outcome was to study the duration of preoperative fasting for solids and clear fluids. Duration of preoperative fasting for solids was defined as the time from last intake of solids till the time of induction of anesthesia. Duration of preoperative fasting for clear fluids was defined as the time from last intake of clear fluids (water, juices without pulp, nonmilk containing tea or coffee, fizzy drinks) till the time of induction of anesthesia. Degree of hunger was defined by the score provided by the patient on the 10-point NRS rated from 0 to 9. Degree of thirst was defined by the score provided by the patient on the NRS. Hunger and thirst scores were subclassified as None: NRS score of 0, Mild: NRS score of 1–3, Moderate: NRS score of 4–6, and Severe: NRS score of 7–9. Clinically relevant hunger or thirst was defined as NRS score of 4 or more. The patients also rated their preoperative anxiety on the NRS from 0 to 9.
The patients were divided into two groups based on the timing of the surgery (morning or afternoon schedule) that they were assigned to. The morning schedule of surgery included patients undergoing surgery between 7.30 AM to 12 noon. The afternoon slot included patients undergoing surgery between 12.30 PM and 4.30 PM. The two groups were compared to find variability in the duration of preoperative fasting times for solids and clear fluids and also with regard to the hunger and thirst scores.
The study data were analyzed using the Statistical Package for social Sciences (Released 2007. SPSS for Windows, Version 16.0. Chicago, SPSS Inc.). Sample size was calculated using the sample size calculation method for absolute precision estimating the population mean (single mean) based on the study by Arun and Korula  This study reported the mean preoperative fasting time and standard deviation as 9.26 h and 4.25 h, respectively; with a precision level of 0.5% and 95% confidence intervals (CIs), the required sample size was 276 patients. Data were screened for outliers and extreme values using Box-Cox plot and histogram (for shape of the distribution). Summary statistics was used for reporting demographic and clinical characteristics. T-test was used for analysis of continuous data with normal distribution and Mann–Whitney U-test for data with nonnormal distribution. Chi-square test was performed for categorical variables and the outcome variable. Differences were considered significant at P < 0.05. Point prevalence of significant hunger and thirst was presented using the formula:
(Number of patients with clinically relevant hunger or thirst scores at a given point in time/patient population for the study at the same time) *100.
| Results|| |
Three hundred and thirty patients were enrolled for the study. [Table 1] presents the baseline demographic data for the study population. The mean duration of fasting for solids for all patients was 12.58 ± 2.70 h with a range of 6–19 h. The mean duration of fasting for clear fluids for all the study participants was 9.02 ± 3.73 h; ranging from 2 to 18 h. [Table 2] presents the fasting data for the patient groups divided according to their surgical schedule times (AM and PM groups). The patients on the morning schedule had significantly shortened duration of fasting for solids as compared to those on the afternoon schedule (P< 0.0001, 95% CI: −3.53 to −2.44). The fasting times for clear fluids for the patients on the morning schedule were statistically comparable to that of the patients posted for the afternoon schedule (P = 0.0742; 95% CI: −0.07–1.65). The point prevalence of clinically significant hunger and thirst was 7.88 and 8.18, respectively, on March 31, 2017. [Figure 1] presents the flow of the study participants.
|Table 2: Comparison of the study groups divided according to the scheduled surgical times|
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As compared with the ASA fasting guidelines of 8 h for solids (fried and fatty food), 93.9% of the patients were fasting for more than 8 h for solids [Figure 2]. Only 4.8% of the study participants took water up to 2 h before surgery in accordance with the ASA fasting guidelines, but the majority of patients were fasting for more than 12 h for clear fluids [Figure 3].
|Figure 2: Distribution of patients according to duration of fasting for solids (hours)|
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|Figure 3: Distribution of patients according to duration of fasting for clear fluids (hours)|
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The hunger scores for the patients are classified as presented in [Figure 4] and ranged from 0 to 9. The thirst scores for patients ranged from 0 to 7 and are depicted in [Figure 5]. Up to 66.7% of the patients reported as not being hungry while clinically relevant hunger (score of 4 or more) was reported by 26 (7.9%) patients. No thirst and clinically relevant thirst scores (4 or more) were reported by 188 (56.9%) and 27 (8.2%) patients, respectively.
| Discussion|| |
Our results prove that patients presenting for day care surgery are fasting for long durations preoperatively despite instructions to fast according to the ASA fasting guidelines. Adequate preoperative fasting is essential to prevent aspiration of gastric contents during surgical procedures. Recent fasting guidelines have questioned the practice of “NPO after midnight.” Most anesthesia societies now recommend liberal rules for preoperative fasting in healthy patients undergoing elective surgery, allowing intake of clear fluids (water, clear juices, coffee, and tea) up to 2 h before surgery.,, Safe fasting period after solids and nonhuman milk is reported as 6 h.,, Various investigators have reported a lag between the existence of preoperative fasting guidelines and their implementation., In a nationwide survey of teaching hospitals in Japan, Shime et al. reported that 90% of anesthetists were applying fasting periods longer than the recommended ASA guidelines; with a median duration of fasting as 12–13 h for solids and 6–9 h for liquids.
Our results are similar to those of previous investigators with regard to prolonged preoperative fasting times during elective surgery.,,,, As reported by others, the mean duration of fasting was significantly longer for patients operated after midday compared to those operated before midday. Majority of our patients were fasting for more than 8 h for solids, and only 4.8% of them took water up to 2 h before surgery in accordance with the ASA fasting guidelines. Similarly, Murphy et al. reported that 85% of their patients followed the nonfood after midnight guideline and only 12% followed ASA guideline.
Overnight fasting can cause considerable distress and discomfort to the patients, due to a feeling of hunger and thirst, compounded by the anxiety associated with the preoperative period. Most of our patients reported as not being hungry; however, 7.9% had a hunger score of 4 or more. Likewise, clinically relevant thirst scores were reported by only 8.2% of our patients. Other investigators have reported higher degree of hunger and thirst among their patient population. In the study by Furrer et al., 33% patients complained of moderate to strong thirst, whereas 19% had moderate to strong hunger. In another study from Iran, 60.8% and 42% of patients were reported to have distressing hunger and thirst, respectively.
Prolonged preoperative fasting times are associated with dehydration, hypoglycemia, and electrolyte imbalance ,,, and can increase the metabolic stress response to surgery; reduce insulin levels, increase glucagon and insulin resistance and loss of lean body mass., Inappropriately prolonged preoperative fasting may lead to delay in discharge from the hospital due to effects such as dizziness, nausea, and vomiting. Thus, prolonged fasting times have deleterious effects on the patients and should be avoided at all costs. Although we provide verbal preoperative fasting instructions according to the ASA preoperative fasting guidelines, to all patients attending the day care surgical facility, most patients are still fasting for longer times than recommended. The reasons for this could include the fear of cancellation of the surgery, lack of institutional guidelines, concern about changes in the schedule of surgical cases, fear of litigation, and the inconvenience of deviating from the ongoing practice. Patients are scheduled for their surgery after a waiting period, and hence, they do not want their surgery to be rescheduled for any reason as this adds a considerable financial burden on them; hence, they are hesitant to follow liberal fasting orders that are given to them by the hospital staff. Whether supplementation of verbal preoperative fasting instructions with written instructions will improve patient compliance needs to be explored in further studies.
We recognize several limitations of our study. Recall bias for the duration of fasting (as patients self-reported the duration of fasting) could be present, but this was minimized by questioning the patients on two occasions, initially (at admission by the staff nurse) and then before induction of anesthesia (by the concerned anesthesiologist) to rule out any inconsistencies. Preoperative anxiety could have influenced the patients' report, but most of the study participants reported low levels of anxiety, and we collected data at the time of admission because a prolonged preoperative waiting period may increase patient anxiety and affect the data collection. None of the participants reported preoperative pain as this could be another confounding factor during data collection. The participation in the study was purely voluntary, and the participants could withdraw from the study at any time if they were unwilling to answer the questions in the questionnaire. As mentioned earlier, we did not include the gynecological patients as these patients are admitted to the wards and then undergo their day care surgical procedures; this could influence the generalizability of our results.
| Conclusions|| |
Patients reporting for day care surgery are fasting for inappropriately long durations despite providing them with verbal instructions to follow liberal fasting guidelines. We need to formulate institutional policies to ensure adherence to the liberal ASA preoperative fasting guidelines. The need to educate patients and staff regarding the importance and benefits of liberal fasting guidelines cannot be overemphasized.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]
[Table 1], [Table 2]