Cardio-vascular and metabolic alterations caused by hemorrhage in fed and starved rats

Role of preoperative carbohydrate loading for prevention of perioperative ketoacidosis in elective cesarean delivery

Background and Aims

Starvation of long duration during third trimester of pregnancy is undesirable as it is associated with accelerated fasting leading to hypoglycemia, raised plasma free fatty acid (FFA) levels, and increased plasma/urinary ketones. Carbohydrate (CHO)-rich drinks given preoperatively may ameliorate these deleterious effects. The enhanced recovery after surgery (ERAS) guidelines for perioperative care recommend that oral CHO fluid supplementation 2 h before cesarean delivery may be offered to nondiabetic pregnant women. The aim of the study was to evaluate the role of preoperative oral CHO loading for the prevention of perioperative ketoacidosis in elective cesarean deliveries.

Material and Methods

One hundred and twenty American Society of Anesthesiologists (ASA) II/III parturients undergoing elective cesarean section under subarachnoid block (SAB) were divided into two groups of 60 each after they gave written informed consent. Group A parturients received 400 ml of filtered water 2 h before surgery. Group B parturients received 400 ml of nonparticulate CHO drink 2 h before surgery. The primary outcome was the incidence of ketonuria studied by the dipstick method. Secondary outcomes included hunger and thirst scores, anxiety score, dominant hand grip strength, and the quality of recovery score.

Results

The urine ketone levels were positive (+1) in 8.3% parturients in group A and 1.7% parturients in the CHO group (P value- 0.094). The hunger and thirst scores as well as the modified Beck's anxiety scores were significantly lower in the CHO group (P value- 0.002). Dominant hand grip strength was preserved in both the groups (P value- 0.827). The quality of recovery score was significantly improved in the CHO group (P value- 0.002). No serious adverse effects were noted in either group.

Conclusion

Oral CHO drink is safe when administered 2 h before uncomplicated elective cesarean deliveries. It may have a positive influence on a wide range of perioperative markers of clinical outcome.

Consequences of Preoperative Oral Carbohydrate Consumption in Septal Deviation Patients Undergoing Endoscopic Septoplasty: A Retrospective Cohort Study

PURPOSE

Multiple reports have demonstrated the benefits of preoperative oral carbohydrates (CHO) in patients receiving open abdominal, thoracic, and orthopedic surgeries. However, thus far, no reports have investigated the benefits of CHO in patients undergoing nasal endoscopic surgery. Our goal was to evaluate the outcome of preoperative oral of administration of CHO in septal deviation patients, undergoing endoscopic septoplasty, under general anesthesia.

DESIGN

A retrospective cohort study from a prospectively collected database.

METHODS

Consecutive 400 septal deviation patients, undergoing endoscopic septoplasty, were randomly assigned to receive CHO or plain water (80 CHO cohort vs. 320 control cohort) before general anesthesia. The primary outcome was the risk of acute postoperative hypertension (APH). The secondary outcomes included length of hospital stay (LOS), hospitalization cost, sleep time the day before surgery, fluid infusion volume on surgical day, as well the incidence of postoperative nausea and vomiting (PONV) and aspiration.

FINDINGS

Patients in the CHO cohort experienced a lower risk of both diastolic blood pressure (DBP)-based APH (OR, 0.49; 95% CI, 0.25 to 0.96; P = 0.0375) and total APH (OR, 0.49; 95% CI, 0.26 to 0.92; P = 0.0258), lower LOS, lower hospitalization cost, longer sleep time and less fluid infusion volume after adjusting for gender, age, BMI, preoperative blood pressure and pulse. Besides, data showed no significant differences in the incidence of (P = 0.4173) and aspiration (P > 0.99).

CONCLUSIONS

Preoperative CHO administration can reduce APH risk in patients undergoing endoscopic septoplasty under general anesthesia. Besides, preoperative CHO administration can improve other clinical outcomes, such as, LOS, hospitalization cost, sleep time, and fluid infusion volume. Moreover, CHO safety was confirmed in our study. In the future, additional investigation is necessary to confirm our results.

Impact of oral carbohydrate consumption prior to cesarean delivery on preoperative well-being: a randomized interventional study

PURPOSE

Oral carbohydrate consumption before surgery improves insulin sensitivity, cardiac output and well-being, and shortens hospital stays without adverse effects. No work has compared higher-dose carbohydrate beverages made for preoperative consumption to common, commercial oral rehydration solutions with lower carbohydrate concentrations.

METHODS

We recruited low-risk women undergoing scheduled cesarean deliveries with planned spinal anesthesia. Participants were randomized to one of three groups: those who consumed Clearfast^® beverage, those who consumed Gatorade Thirst Quencher^® beverage, or fasting control. Participants in the two beverage groups received 710 mL of the appropriate beverage the night before surgery and 355 mL 2 h before surgery. Participants in the control group fasted after midnight the night before surgery. Two hours before surgery, we recorded baseline patient well-being using visual analogue scales, followed by beverage consumption for subjects in the beverage groups. One hour later, we repeated the same assessment. Additional recorded measures included cord blood glucose level, intraoperative variables, breastfeeding success, and a quality of recovery assessment administered 1 day after surgery.

RESULTS

Forty-seven patients were recruited: 15 received Clearfast^®, 17 received Gatorade Thirst Quencher^®, and 15 patients fasted after midnight. Group differences in change in patient well-being using visual analog scales were analyzed using linear regression. Both beverage-consuming groups showed significant improvements in patient well-being using visual analog scales while fasted patients showed no change.

CONCLUSION

Either a common oral rehydration beverage or a higher-dose carbohydrate beverage consumed preoperatively resulted in superior well-being compared to fasting. No differences in other outcomes were noted.

TRIAL REGISTRATION

This study was registered on ClinicalTrials.gov with clinical trial registration number: NCT02684513.

Preinjury Fed State Alters the Physiologic Response in a Porcine Model of Hemorrhagic Shock and Polytrauma

INTRODUCTION

Hemorrhagic shock and injury lead to dramatic changes in metabolic demands and continue to be a leading cause of death. We hypothesized that altering the preinjury metabolic state with a carbohydrate load prior to injury would affect subsequent metabolic responses to injury and lead to improved survival.

METHODS

Sixty-four pigs were randomized to fasted (F) or carbohydrate prefeeding (CPF) groups and fasted 12 h prior to experiment. The CPF pigs received an oral carbohydrate load 1 h prior to anesthesia. All pigs underwent a standardized injury/hemorrhagic shock protocol. Physiologic parameters and laboratory values were obtained at set time points.

RESULTS

Carbohydrate prefeeding did not convey a survival benefit; instead, CPF animals had greater mortality rates (47% vs. 28%; P = 0.153; log-rank [Mantel-Cox]). Carbohydrate prefeeding animals also had higher rates of acute lung injury (odds ratio, 4.23; 95% confidence interval, 1.1-16.3) and altered oxygen utilization. Prior to shock and throughout resuscitation, CPF animals had significantly higher serum glucose levels than did the F animals.

CONCLUSIONS

Carbohydrate prefeeding did not provide a survival benefit to swine subjected to hemorrhagic shock and polytrauma. Carbohydrate prefeeding led to significantly different metabolic profile than in fasted animals, and prefeeding led to a greater incidence of lung injury, increased multiorgan dysfunction, and altered oxygen utilization.

Oral carbohydrate solution ameliorates endotoxemia-induced splanchnic ischemia

The purpose of this study was to investigate the effect of oral administration of a simple carbohydrate solution on splanchnic circulation and bacterial translocation in endotoxemia. Group 1 was sham control; group 2 was starved for 24 hours; in group 3, endotoxin was administrated at the end of starvation; in group 4, carbohydrate solution was administrated via orogastric route for 24 hours; and in group 5, carbohydrate solution was given and endotoxin was administrated at the end of 24 hours. Splanchnic blood flows were recorded and tissue samples were collected for microbiological analyses. There was a significant increase (P<.05) in the incidence of bacterial translocation in starvation. Endotoxemia decreased distal (P=.021) and midmesenteric (P=.046) flow in starved animals. Oral carbohydrate significantly increased ileal blood flow in starvation (P=.036) and endotoxemia (P=.008). In conclusion, oral carbohydrate solution prevents bacterial translocation during starvation and endotoxemia. The possible mechanism is the improvement in the mesenteric blood flow.

Preoperative Oral Carbohydrate Administration to ASA III-IV Patients Undergoing Elective Cardiac Surgery

In this study we investigated the effects of preoperative oral carbohydrate administration on postoperative insulin resistance (PIR), gastric fluid volume, preoperative discomfort, and variables of organ dysfunction in ASA physical status III-IV patients undergoing elective cardiac surgery, including those with noninsulin-dependent Type-2 diabetes mellitus. Before surgery, 188 patients were randomized to receive a clear 12.5% carbohydrate drink (CHO), flavored water (placebo), or to fast overnight (control). CHO and placebo were treated in double-blind format and received 800 mL of the corresponding beverage in the evening and 400 mL 2 h before surgery. Patients were monitored from induction of general anesthesia until 24 h postoperatively. Exogenous insulin requirements to control blood glucose levels <or=10.0 mmol/L were used as a marker for PIR. Gastric fluid volume was measured by passive gastric reflux and preoperative discomfort using visual analog scales. Postoperative clinical and surgical data were recorded. Blood glucose levels and insulin requirements did not differ between groups. Patients receiving CHO and placebo were less thirsty compared with controls (P < 0.01 and P = 0.06, respectively). Ingested liquids did not cause increased gastric fluid volume or other adverse events. The CHO group required less intraoperative inotropic support after initiation of cardiopulmonary bypass weaning (P < 0.05). In conclusion, preoperative CHO administration before cardiac surgery does not affect PIR. Clear fluids reduce thirst and may be recommended as a safe procedure in ASA III-IV patients. Further research is indicated to investigate possible cardioprotective effects of preoperative CHO intake.

Preoperative fasting: an outdated concept?

Recent studies have shown that fasting during the preoperative period for elective surgery induces a metabolic state that seems unfavorable for patients. Results from animal studies indicate that rapid depletion of liver glycogen before surgery leads to mobilization of muscle glycogen after surgery, in turn leading to reduced muscle strength. Depletion of liver glycogen also influences the function of the mononuclear phagocytic system (MPS), which is located predominantly in the liver. The MPS is essential in restricting endotoxin, which may translocate from the gut. In addition, surgery per se puts a substantial physical strain on the patient, and fasting may adversely affect the metabolic response to surgery. This paper presents experimental and clinical data that, when combined together, prove that fasting before surgery has adverse consequences for the patient.

Preoperative feeding preserves heart function and decreases oxidative injury in rats

OBJECTIVE

The nutritional status of a patient has been implicated as an important factor in the development of postoperative complications. Fasting before an operation may have detrimental effects on the metabolic state. We hypothesized that there was a positive correlation between preoperative nutritional status and postoperative organ function.

METHODS

Preoperative feeding was compared with fasting with respect to effects on organ function and biochemical parameters in an animal model of extensive large abdominal surgery. Male Wistar rats were fed ad libitum or fasted for 16 h, after which the arteria mesenterica superior was clamped for 60 min followed by 180 min of reperfusion.

RESULTS

After the ischemic period, heart function was significantly better in animals that were fed ad libitum than in fasted animals. Moreover, after intestinal ischemia and reperfusion, fed rats showed significantly higher levels of intestinal adenosine triphosphate and a significantly higher malondialdehyde concentration in the intestine and lung than did fasted rats. The ratio of adenosine triphosphate to adenosine diphosphate in the liver, an indicator of energy status, in fed rats was similar to that in a sham group, whereas fasted animals showed a significantly lower value.

CONCLUSIONS

Preoperative nutrition in contrast to fasting may attenuate ischemia/reperfusion-induced injury and preserve organ function in the rat.

Bulking fibre prevents translocation to mesenteric lymph nodes of an efficiently translocating Escherichia coli strain in rats

BACKGROUND

starvation for 24 h prior to experimental haemorrhage increases bacterial translocation in rats. Forty-eight hours starvation alone causes pronounced microbiological changes in caecal contents and a marked increase in bacterial adherence to caecal epithelium. The aim of the present study was to examine whether bulking fibre prevents these microbiological changes induced by starvation, i.e. mucosal adherence and/or bacterial translocation with and without haemorrhage in rats.

METHODS

32 rats were inoculated with the translocating Escherichia coli strain Kl-C1. Groups of these rats were then starved for 48 h with or without access to bulking fibre. An additional group of rats was given bulking fibre and subjected to haemorrhage. A control group was untreated and given regular food. Samples were taken from caecal contents, caecal epithelium, mesenteric lymph nodes and blood. A biochemical fingerprinting method was used to characterize and compare E. coli strains in all samples.

RESULTS

ingestion of bulking fibre alone for 48 h significantly reduced the frequency of Kl-C1 both in caecal contents and on caecal epithelium and completely prevented translocation of the strain, compared to starvation without bulking fibre for 48 h. Enforced stress (haemorrhage) increased bacterial translocation to the same level as starvation for 48 h. E. coli phenotypes found in mesenteric lymph nodes were also found adhering to the caecal epithelium.

CONCLUSIONS

The presence of bulking fibre in gut lumen, by unknown mechanisms, reduces the frequency of an inoculated translocating strain of E. coli in caecal contents and on caecal epithelium and prevents its translocation to mesenteric lymph nodes.

Pre-stress carbohydrate solution prevents fatal outcome after hemorrhage in 24-hour food-deprived rats

Twenty-four-hour food deprivation increases mortality after experimental hemorrhage. Survival after hemorrhage is closely related to the capacity of the animal to develop hyperglycemia. In this study, 24-h food-deprived rats were subjected to hemorrhage over a period of 75 min, standardized to reach a final blood pressure of 45 mmHg. Just prior to hemorrhage, the rats ingested a carbohydrate solution (n = 8) 2.16 mL/100 g body weight (b.wt.) or the same volume of water sweetened with sodiumsaccarinate (n = 7). A third group (n = 8) received an i.v. infusion of 5% glucose 0.5 mL/100 g b. wt. to mimic the hyperglycemia during hemorrhage of rats taking carbohydrates before stress. During hemorrhage rats treated with oral carbohydrate and i.v. glucose developed moderate hyperglycemia while glucose levels fell in water-treated rats (P < 0.001). Concomitant developments in hematocrits indicated improved plasma refill in carbohydrate- and glucose-treated animals versus controls (P < 0.05). There were no significant differences in blood pressure by the end of hemorrhage. Six of the seven animals treated with water died within 2 h of bleeding. In both the carbohydrate- and the glucose-treated groups 7 of 8 animals recovered and survived the 7-d observation period (P < 0.05 versus controls). It is concluded that oral carbohydrate solution before hemorrhage can alter the outcome after experimental hemorrhage. The similar finding in rats given i.v. glucose suggests that the key factor for survival was the capacity to mount a state of hyperglycemia during hemorrhage.

Composition and diversity of intestinal coliform flora influence bacterial translocation in rats after hemorrhagic stress

Coliform bacteria are the most frequently reported bacteria to translocate after hemorrhage. We investigated the correlation between composition and diversity of the cecal coliform flora and the degree of translocation in a rat model of hemorrhagic stress. Two groups of nine rats each were bled to 60 and 50 mm Hg mean arterial blood pressure, respectively. A sham-operated group without bleeding (n = 9) and a noninstrumented group (n = 6) served as controls. From each rat, 40 coliform isolates from the cecum and up to 16 from positive mesenteric lymph node (MLN) cultures were tested with an automated biochemical fingerprinting method. The phenotypic diversity of coliforms in each cecal sample was calculated as Simpson's diversity index (DI), and similarities between bacterial types in different samples were calculated as population similarity coefficients. Three rats in the sham-operated group and seven in each of the bled groups showed bacterial translocation. Of the different biochemical phenotypes (BPTs) found in the cecum of bled rats (mean, 6.5 BPTs), only a few were detected in MLNs (mean, 1.9 BPTs per MLN), with Escherichia coli being the dominant species. The translocating E. coli strains were mainly of two BPTs. Rats showing no translocation either did not carry these strains or had a high diversity of coliforms in the cecum. Furthermore, translocation of these coliform types was independent of their proportion in the cecum. In bled rats, the diversity of coliforms (mean DI, 0.53) was significantly higher than that in control groups (mean DI, 0.30; P = 0.004), suggesting that hemorrhage stimulates an increase in diversity of cecal coliforms. Rats with similar coliform flora and subjected to the same treatment showed similar patterns of translocation. Our results suggest that the composition of the coliform flora is an important factor in translocation and that certain coliform strains have the ability to translocate and survive in MLNs more easily than others.

Food deprivation alters liver glycogen metabolism and endocrine responses to hemorrhage

Liver glycogen content, blood glucose, insulin, glucagon, and epinephrine were determined during 1 h hemorrhagic hypotension at 60 mmHg and 23 h thereafter in fed and two groups of 24-h food-deprived rats receiving either no infusion or 30% glucose intravenously during hemorrhage. Liver glycogen content was reduced by greater than 90% after 24-h food deprivation. Fed and food-deprived rats given glucose developed similar and substantial elevations of blood glucose during hemorrhage, whereas changes in blood glucose were modest in food-deprived rats given no infusion. In fed rats, liver glycogen was reduced by 60% during the 1-h bleed, but within 2 h after hemorrhage repletion of liver glycogen content commenced. By 6 h, approximately 75% of the glycogen lost during hemorrhage had been restored, and 23 h after hemorrhage liver glycogen content was six times greater compared with nonbled controls. Although glycogen levels increased after hemorrhage in food-deprived animals, the increase was negligible compared with that found in fed rats. Infusion of glucose during hemorrhage or adrenergic blockade after hemorrhage did not alter glycogen repletion in food-deprived rats. Posthemorrhage fed animals had high levels of insulin, glucagon, and epinephrine during hemorrhage, whereas insulin levels remained low in food-deprived rats despite exogenously induced hyperglycemia. It is concluded that rapid and substantial glycogen repletion can occur even immediately poststress. The conditions seem to be related to the nutritional state at the time of the insult.

Modification of cardio-vascular responses to hemorrhage by induced hyperosmolality in the rat

Starved rats sedated with a neurolept analgesic were subjected to hemorrhagic hypotension while receiving infusions of iso-osmolar and hyperosmolar solutions. The hemorrhage model used resulted in similar residual blood volumes and hematocrits in all groups. The non-metabolizable pentose, xylose, and glucose were used to induce a state of hyperosmolality, which was absent in those animals which received iso-osmolar infusions (0.29 M xylose). After 45 mins hemorrhagic hypotension and a blood loss equal to 40% of the initial blood volume, the animals receiving the hyperosmolar infusions had a better cardiovascular status compared to those which received the iso-osmolar infusions. The cardiac outputs and stroke volumes were higher and heart rate lower in the hyperosmolar groups. Evidence of better tissue perfusion was obtained in those animals with the induced state of hyperosmolality.