Preoperative fasting procedures : let's use the evidence

Today's anaesthetic techniques are improved and pulmonary aspiration in elective surgical patients is rare. The purpose of fasting guidelines for healthy, low risk patients undergoing elective surgery is to minimize the volume of gastric contents while avoiding unnecessary thirst and dehydration. Fasting guidelines should be based on the best available evidence and in the absence of evidence, on the knowledge of gastrointestinal physiology.

Safe perioperative fasting : implementation of evidence based guidelines and an ‘at risk’ checklist

Introduction Guidelines existed at the Royal Children’s Hospital (RCH) to direct preoperative/pre-procedural fasting in day patients undergoing general anaesthetic. However audit, risk analyses and a recent research project at the RCH identified prolonged pre-procedural fasting times in children undergoing day surgical and gastroenterology procedures. Aims 1. Reduce median fasting time to <8 hrs for children admitted for a day procedure under general anaesthetic; 2. Identify children at risk of perioperative hypoglycaemia. Methods The study was conducted in 4 phases: 1) revision and implementation of evidence-based perioperative fasting guidelines with staff education relating to these guidelines; 2) cross-sectional descriptive study with day surgical patients (n = 377) requiring preoperative fasting. ‘Normal risk’ and ‘High risk’ groups were identified for fasting hypoglycaemia using an ‘at risk’ checklist. Venous blood glucose (BGL) testing was performed at a) anaesthetic induction; b) prior to first caloric food/fluid postoperatively; 3) chart audit to evaluate efficacy of guidelines and parent information; 4) development of recommendations for clinical practice. Results The median fasting time for children having morning surgery (14 hrs, IQ range 5–22 hrs) was twice as long compared to afternoon lists (7 hrs, IQ range 6–22 hrs) (p < 0.001). Median fasting times were not significantly different between ‘at risk’ and control groups (p = 0.496). However the proportion of children who experienced hypoglycaemia (BGL <3 mmol/L) was greater in the ‘at risk’ group (5, 8%) compared to the control group (18, 4.3%). Although not statistically significant (x2 = 2.254, p = 0.133), ‘at risk’ children appear more likely to experience hypoglycaemia as children in the control group, constituting a clinically significant finding. Conclusion Appropriate identification and management of ‘high risk’ children, will reduce the risk of deleterious sequelae in children undergoing surgical or investigative procedures requiring general anaesthesia.

Pre-operative fasting for intravenous conscious sedation used in dental treatment: are conclusions based on relative risk management or evidence?

Intravenous sedation is a widely used pharmacological method of patient management commonly used in dental surgery for the treatment of anxious patients. Variety exists in fasting regimes between different centres offering dental sedation, with some advocating starvation in line with general anaesthesia protocols and others not enforcing starvation at all. The currently available guidelines on fasting protocols are ambiguous and open to interpretation partly because they are based on expert opinion rather than evidence-based research. This article reviews the available evidence on the subject of pre-operative fasting and discusses current guidelines.

Different fasting periods in tiletamine-zolezepam-anethetized cats: Glycemia, recovery, blood-gas and cardiorrespiratory parameters

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Evaluation of the Effects of a Preoperative 2-Hour Fast With Maltodextrine and Glutamine on Insulin Resistance, Acute-Phase Response, Nitrogen Balance, and Serum Glutathione After Laparoscopic Cholecystectomy: A Controlled Randomized Trial

Background: Prolonged preoperative fasting increases insulin resistance (IR). The authors investigated whether an abbreviated preoperative fast with glutamine (GLN) plus a carbohydrate (CHO)-based beverage would improve the organic response after surgery. Methods: Forty-eight female patients (19-62 years) were randomized to either standard fasting (control group) or to fasting with 1 of 3 different beverages before video-cholecystectomy. Beverages were consumed 8 hours (400 mL; placebo group: water; GLN group: water with 50 g maltodextrine plus 40 g GLN; and CHO group: water with 50 g maltodextrine) and 2 hours (200 mL; placebo: water; GLN: water with 25 g maltodextrine plus 10 g GLN; and CHO: water with 25 g maltodextrine) before anesthesia. Blood samples were collected pre- and postoperatively. Results: The mean (SEM) postoperative homeostasis model assessment-insulin resistance was greater (P < .05) in control patients (4.3 [1.3]) than in the other groups (placebo, 1.6 [0.3]; CHO, 2.3 [0.4]; and GLN, 1.5 [0.1]). Glutathione was significantly higher (P < .01) in the GLN group than in both CHO and control groups. Interleukin-6 increased in all groups except the GLN group. The C-reactive protein/albumin ratio was higher (P < .05) in controls than in CHO and GLN groups. The nitrogen balance was less negative in GLN (-2.5 [0.8] gN) than in both placebo (-9.0 [2] gN; P = .001) and control (-6.6 [0.4] gN; P = .04) groups. Conclusions Preoperative intake of a GLN-enriched CHO beverage appears to improve IR and antioxidant defenses and decreases the inflammatory response after video-cholecystectomy. (JPEN J Parenter Enteral Nutr. 2012; 36: 43-52)

Intubação traqueal e o paciente com o estômago cheio

A aspiração pulmonar do conteúdo gástrico, apesar de pouco frequente, exige cuidados especiais para sua prevenção. A depressão da consciência durante a anestesia predispõe os pacientes a esta grave complicação pela diminuição na função do esfíncter esofágico e dos reflexos protetores das vias aéreas. Guias de jejum pré-operatório elaborados recentemente sugerem períodos menores de jejum, principalmente para líquidos, permitindo mais conforto aos pacientes e menor risco de hipoglicemia e desidratação, sem aumentar a incidência de aspiração pulmonar perioperatória. O uso rotineiro de agentes que diminuem a acidez e volume gástrico parece estar indicado apenas para pacientes de risco. A intubação traqueal após indução anestésica por meio da técnica de sequência rápida está indicada naqueles pacientes, com risco de aspiração gástrica, em que não há suspeita de intubação traqueal difícil. A indicação correta da técnica, sua aplicação criteriosa e a utilização racional das drogas disponíveis podem promover condições excelentes de intubação, com curto período de latência, rápido retorno da consciência e da respiração espontânea, caso haja falha na intubação traqueal.O presente artigo tem como objetivo discutir os métodos atualmente utilizados para controlar o volume e o pH do conteúdo gástrico, proteger as vias aéreas durante as manobras de intubação e reduzir o refluxo gastroesofágico.

Correlação de diferentes períodos de jejum com níveis séricos de cortisol, glicemia plasmática, estado clínico e equilíbrio ácido-base em case submetidos à anestesia geral inalatória

This study correlated the solid preoperative fasting periods with plasma glycemia, serum cortisol, condition clinic and acid-base balance in dogs submitted to inhalation of general anaesthesia. Eight adults, animals were distributed into three groups in accordance with solid preoperative fasting: group 1 (12 hours), group 2 (18 hours) and group 3 (24 hours). Gastric emptying was observed and following this animals were submitted to the same anesthetic procedure. Heart and respiratory rate, rectal temperature, capillary refill time, percent hydration and noninvasive arterial pressure determined before and after Acepromazine and every 10 minutes during anaesthesia, included ETCO 2; values blood gas (pH, PaCO 2, PaO 2, HCO 3, TCO 2, SaO 2, BE), glycemic and serum cortisol were analyzed before MPA and each 30 minutes during anaesthesia. In recovery anaesthetic, glycemia and serum cortisol were repeated. During anaesthesia there were little cardiovascular and respiratory alteration not having interference of the preoperative fasting periods. Animals with 12 hours of the preoperative fasting showed a higher rise in glycemia levels than others groups in recovery anaesthetic. Serum cortisol wasn't influenced by fasting. Solid preoperative fasting independent of the duration describe a discreet respiratory alkalosis. All animals showed good clinical condition in all three groups. Solid preoperative fasting of the 18 hours is recommended to ensure a complete absence of the solid food contents in stomach.

Comparação entre diferentes períodos de jejum em cães submetidos à anestesia geral inalatória: aspectos clínicos, bioquímicos e eletrolíticos

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Fasting and the female body : from the ascetic to the pathological

This paper will examine the literature on ‘anorexia nervosa’, and argue that it is underpinned by three fundamental assumptions. First, ‘anorexia nervosa’ is a reflection of the mismatch between true ‘inner self’ and the external ‘false self’, the latter self being the distorted product of a male dominated society. Second, the explanation for the severe fasting practices constitutive of ‘anorexia nervosa’ (a new social problem) is to be found within the binary opposition of resistance/conformity to contemporary cultural expectations. Finally, ‘anorexia nervosa’ is a problem which exists in nature (i.e., independently of analysis). It was eventually discovered, named and explained. This paper will problematise each of these assumptions in turn, and in doing so, it will propose an alternative way of understanding contemporary fasting practices.

Effectiveness of nurse-led preoperative assessment services for elective surgery : a systematic review

Background--The admission and assessment of patients for elective procedures is a task faced by all healthcare organisations that provide elective surgical services. Several different strategies have been used to facilitate the management of these tasks. Nurse-led preadmission clinics or services have been implemented in many health services as one of these management strategies; however their effectiveness has not been established. Objectives--The objective of this review was to examine the available research on the effectiveness of nurse-led elective surgery preoperative assessment clinics or services on patient outcomes.--Results--Of the 19 included articles, there were 10 audits of patient and hospital data, 3 surveys or questionnaires, 3 descriptive studies, 1 action research design, 1 prospective observational study and 1 RCT. Five of ten studies reporting data on cancellations rates found that nurse-led preadmission services reduced the number of day-of-surgery cancellations. Non-attendance for surgery was also reduced, with nine studies reporting decreases in the number of patients failing to attend. Eight studies reporting data on patient or parent satisfaction found high levels of satisfaction with nurse-led preadmission services. Three of four studies investigating the effect of the nurse-led preadmission service on patient anxiety found a reduction in reported anxiety levels. Three studies found that preoperative preparation was enhanced by the use of a nurse-led preadmission service.--Conclusions--While all included studies reported evidence of effectiveness for nurse-led preadmission services on a wide range of outcomes for elective surgery patients, the lack of experimental trials means that the level of evidence is low, and further research is needed.--Implications for practice--Nurse-led preadmission services may be an effective strategy for reducing procedural cancellations, failure to attend for procedures, and patient anxiety, however currently the evidence level is low.

Does preoperative oral carbohydrate reduce hospital stay?

Background Carbohydrate-rich fluids are used to improve postoperative recovery but the effectiveness of the product for reducing length of hospital stay is uncertain. Objective To assess the effectiveness of preoperative loading with carbohydrates on postoperative outcomes. Participants Forty six patients booked for elective colorectal surgery. Methods Participants were allocated to a Carbohydrate-rich fluid group or Usual Care group during their pre-admission clinic visit. The primary outcome was ‘Time to readiness for discharge’. Results Patients in the control group spent on average 4.3 days (95% confidence interval 3.2 to 5.7) and the Carbohydrate-rich fluid group spent 4.1 days (95% confidence interval 3.2 to 5.4) until the primary outcome was met (p=0.824). Conclusion The safety of preoperative high carbohydrate fluids is supported but we were unable to confirm or refute the benefit of CHO for shorter hospital stay following elective colorectal surgery.

Author response: "NPO practices and preoperative oral carbohydrate intake"

"We thank Dr Marsh for his thoughtful comments and acknowledge the limitations of our study, which we clearly outlined in the article. We also thank Dr Marsh for supporting our call for larger, independent trials to test the effectiveness of preoperative consumption of highcarbohydrate fluids to improve patient outcomes..."

Fasting increases serum bilirubin levels in clinically normal, healthy males but not females : a retrospective study from phase I clinical trial participants

Aim: To examine if fasting affects serum bilirubin levels in clinical healthy males and females. Methods: We utilised retrospective data from phase 1 clinical trials where blood was collected in either a fed or fasting state at screening and pre-dosing time points and analysed for total bilirubin levels as per standard clinical procedures. Participants were clinically healthy males (n = 105) or females (n = 30) aged 18 to 48 inclusive who participated in a phase 1 clinical trial in 2012 or 2013. Results: We found a statistically significant increase in total serum bilirubin levels in fasting males as compared to non-fasting males. The fasting time correlated positively with increased bilirubin levels. The age of the healthy males did not correlate with their fasting bilirubin level. We found no correlation between fasting and bilirubin levels in clinically normal females. Conclusions: The recruitment and screening of volunteers for a clinical trial is a time-consuming and expensive process. This study clearly demonstrates that testing for serum bilirubin should be conducted on non-fasting male subjects. If fasting is required, then participants should not be excluded from a trial based on an elevated serum bilirubin that is deemed non-clinically significant.

Preoperative bathing or showering with skin antiseptics to prevent surgical site infection

Background Surgical site infections (SSIs) are wound infections that occur after invasive (surgical) procedures. Preoperative bathing or showering with an antiseptic skin wash product is a well-accepted procedure for reducing skin bacteria (microflora). It is less clear whether reducing skin microflora leads to a lower incidence of surgical site infection. Objectives To review the evidence for preoperative bathing or showering with antiseptics for preventing hospital-acquired (nosocomial) surgical site infections. Search methods For this fifth update we searched the Cochrane Wounds Group Specialised Register (searched 18 December 2014); the Cochrane Central Register of Controlled Trials (The Cochrane Library 2014 Issue 11); Ovid MEDLINE (2012 to December Week 4 2014), Ovid MEDLINE (In-Process & Other Non-Indexed Citations December 18, 2014); Ovid EMBASE (2012 to 2014 Week 51), EBSCO CINAHL (2012 to December 18 2014) and reference lists of articles. Selection criteria Randomised controlled trials comparing any antiseptic preparation used for preoperative full-body bathing or showering with non-antiseptic preparations in people undergoing surgery. Data collection and analysis Two review authors independently assessed studies for selection, risk of bias and extracted data. Study authors were contacted for additional information. Main results We did not identify any new trials for inclusion in this fifth update. Seven trials involving a total of 10,157 participants were included. Four of the included trials had three comparison groups. The antiseptic used in all trials was 4% chlorhexidine gluconate (Hibiscrub/Riohex). Three trials involving 7791 participants compared chlorhexidine with a placebo. Bathing with chlorhexidine compared with placebo did not result in a statistically significant reduction in SSIs; the relative risk of SSI (RR) was 0.91 (95% confidence interval (CI) 0.80 to 1.04). When only trials of high quality were included in this comparison, the RR of SSI was 0.95 (95%CI 0.82 to 1.10). Three trials of 1443 participants compared bar soap with chlorhexidine; when combined there was no difference in the risk of SSIs (RR 1.02, 95% CI 0.57 to 1.84). Three trials of 1192 patients compared bathing with chlorhexidine with no washing, one large study found a statistically significant difference in favour of bathing with chlorhexidine (RR 0.36, 95%CI 0.17 to 0.79). The smaller studies found no difference between patients who washed with chlorhexidine and those who did not wash preoperatively. Authors' conclusions This review provides no clear evidence of benefit for preoperative showering or bathing with chlorhexidine over other wash products, to reduce surgical site infection. Efforts to reduce the incidence of nosocomial surgical site infection should focus on interventions where effect has been demonstrated.