Preoperative fasting guidelines for cataract surgery under regional anaesthesia

Reactive Hypoglycemia in Patients Prior to Cataract Surgery: A Case Series

Cataract surgery is one of the most frequently performed surgical procedures and is often performed under topical anesthesia in conscious patients. Sweating, palpitations, and anxiety may be seen in patients about to undergo surgery. However, these are typical adrenergic symptoms of hypoglycemia and should be further investigated if occurring before surgery. Here, we report five cases of postprandial or reactive hypoglycemia observed in hospital settings just before conducting cataract surgeries in non-diabetic 52-78-year-old patients from 2019 to 2023.

Validation of a novel patient satisfaction questionnaire for preoperative fasting in cataract surgery: a discrimination analysis

OBJECTIVE

Preoperative fasting is routinely performed to prevent anaesthesia-related pulmonary aspiration. To capture patients' experiences with preoperative fasting, a 13-item questionnaire was developed and validated using Rasch analysis and shortened to 6 items. This extension study aims to assess this questionnaire's ability to discriminate between participants with a short versus long duration of fasting and early versus late day surgery.

DESIGN

Single-centred cross-sectional study.

PARTICIPANTS

Subjects were recruited via consecutive sampling of cataract patients on surgery day at Kensington Eye Institute in Toronto from February to December 2019.

METHODS

A validated preoperative fasting questionnaire was administered. Discriminative ability was assessed by comparing responses in patients scheduled for surgery in the morning (8:00 am-12:00 pm) versus afternoon (12:00 pm-3:30 pm) and fasting for short (≤8 hours) versus long (>8 hours) duration. Diagnostic ability of the 6-item questionnaire relative to the 13-item questionnaire was assessed with receiver operating characteristics curve analysis.

RESULTS

A total of 164 patients (mean age 70.8 ± 10.0 years; 57% female) were included. Total scores of patients having surgery in the morning were greater (i.e., less fasting-related burden) than in the afternoon (p = 0.04). There was no significant difference in scores between patients fasting for a short versus long duration (p > 0.05). Receiver operating characteristics curve analysis showed excellent diagnostic ability of the 6-item questionnaire relative to the 13-item version (area under the curve = 0.964).

CONCLUSION

The 6-item questionnaire for fasting-related burden has excellent discriminative ability between early versus late surgery patients. The time fasting while awake may be a more relevant predictor of fasting-related burden relative to the total duration of fasting.

Development and Validation of a Questionnaire Assessing Patient Distress from Preoperative Fasting in Cataract Surgery

Purpose: To develop and psychometrically validate a questionnaire to measure patient distress with preoperative fasting related to cataract surgery.Methods: In this single-centered cross-sectional study, consecutive sampling of cataract patients was undertaken immediately preoperatively from February to December 2019. A questionnaire evaluating patient distress with fasting was designed and administered. Questionnaire development occurred in an iterative process and was conducted with consultation from expert investigators and patients. Validation and psychometric evaluation of the questionnaire were performed with Rasch analysis.Results: A preliminary version of the questionnaire was developed by 10 study investigators. Across five iterations of development, the questionnaire was administered to 186 cataract patients. Psychometric evaluation of the 13-item questionnaire demonstrated ordered thresholds, acceptable item calibration and fit, adequate internal consistency, ability to discriminate between three levels of distress from preoperative fasting and no notable differential item functioning. However, issues with mistargeting, clustering of items on the person-item map and multidimensionality remained. Given these concerns, 13 separate re-analyses were conducted via removal of certain items. A 6-item subset was determined to be well targeted, unidimensional, did not display item clustering and was able to discriminate between patients with high and low distress from preoperative fasting.Conclusion: A 6-item questionnaire is a valid, psychometrically robust and reliable measure for the assessment of patient distress with preoperative fasting in cataract surgery. Items include hunger, thirst, hoarseness, weakness, anxiety and nausea. Future studies should seek to validate this questionnaire across a variety of sociodemographic contexts, languages and specialties.

An international multidisciplinary consensus statement on fasting before procedural sedation in adults and children

The multidisciplinary International Committee for the Advancement of Procedural Sedation presents the first fasting and aspiration prevention recommendations specific to procedural sedation, based on an extensive review of the literature. These were developed using Delphi methodology and assessment of the robustness of the available evidence. The literature evidence is clear that fasting, as currently practiced, often substantially exceeds recommended time thresholds and has known adverse consequences, for example, irritability, dehydration and hypoglycaemia. Fasting does not guarantee an empty stomach, and there is no observed association between aspiration and compliance with common fasting guidelines. The probability of clinically important aspiration during procedural sedation is negligible. In the post-1984 literature there are no published reports of aspiration-associated mortality in children, no reports of death in healthy adults (ASA physical status 1 or 2) and just nine reported deaths in adults of ASA physical status 3 or above. Current concerns about aspiration are out of proportion to the actual risk. Given the lower observed frequency of aspiration and mortality than during general anaesthesia, and the theoretical basis for assuming a lesser risk, fasting strategies in procedural sedation can reasonably be less restrictive. We present a consensus-derived algorithm in which each patient is first risk-stratified during their pre-sedation assessment, using evidence-based factors relating to patient characteristics, comorbidities, the nature of the procedure and the nature of the anticipated sedation technique. Graded fasting precautions for liquids and solids are then recommended for elective procedures based upon this categorisation of negligible, mild or moderate aspiration risk. This consensus statement can serve as a resource to practitioners and policymakers who perform and oversee procedural sedation in patients of all ages, worldwide.

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.

Pre-operative fasting guidelines: an update

Liberal pre-operative fasting routines have been implemented in most countries. In general, clear fluids are allowed up to 2 h before anaesthesia, and light meals up to 6 h. The same recommendations apply for children and pregnant women not in labour. In children <6 months, most recommendations now allow breast- or formula milk feeding up to 4 h before anaesthesia. Recently, the concept of pre-operative oral nutrition using a special carbohydrate-rich beverage has also gained support and been shown not to increase gastric fluid volume or acidity. Based on the available literature, our Task Force has produced new consensus-based Scandinavian guidelines for pre-operative fasting. What is still not clear is to what extent the new liberal fasting routines should apply to patients with functional dyspepsia or systematic diseases such as diabetes mellitus. Other still controversial areas include the need for and effect of fasting in emergency patients, women in labour and in association with procedures done under 'deep sedation'. We think more research on the effect of various fasting regimes in subpopulations of patients is needed before we can move one step further towards completely evidence-based pre-operative fasting guidelines.

Fasting regimens for regional ophthalmic anaesthesia. A survey of members of the British Ophthalmic Anaesthesia Society

Members of the British Ophthalmic Anaesthesia Society were surveyed using a postal questionnaire. The response rate was 72.3%. Respondents were asked about starvation before regional anaesthesia for cataract surgery, the use of sedation in these patients, monitoring and if oxygen supplementation was given. The results show that most patients are not starved before this type of regional anaesthesia, and that the majority of patients receive no supplementary sedation or intravenous analgesia. Over 70% of patients received oxygen supplementation.

Pulmonary oedema after ophthalmic regional anaesthesia in an unfasted patient undergoing elective surgery

An elderly female patient presenting for phaco-emulsification and intra-ocular lens implant under local anaesthesia developed pulmonary oedema after surgery and underwent emergency tracheal intubation. The pulmonary oedema may have been caused by her omission of routine oral diuretic medication before surgery and having to lie flat for the procedure. The patient had not been fasted before surgery, as is accepted practice in many hospitals. This made emergency tracheal intubation potentially hazardous. The patient made a full recovery. The issues of pre-operative assessment, fasting and the withholding of diuretic medication before elective eye surgery under local anaesthesia are discussed.