Small intestinal motor patterns in critically ill patients after major abdominal surgery

Acute Respiratory Failure

Acute respiratory failure occurs when the lungs fail to oxygenate arterial blood adequately and it is one of the commonest postoperative complications. The preoperative identification of risk factors for postoperative acute respiratory failure allows identification of those patients who may benefit from preoperative optimization and increased postoperative vigilance. Multiple postoperative pulmonary complications are associated with acute hypoxemic respiratory failure and this chapter discusses atelectasis, pulmonary embolism, aspiration, and acute respiratory distress syndrome in detail, as well as providing a unified clinical approach to the acutely hypoxemic perioperative patient.

Feasibility and safety of a novel electromagnetic device for small-bore feeding tube placement

BACKGROUND

Misplacement of enteral feeding tubes (EFT) in the lungs is a serious and potentially fatal event. A recent Food and Drug Administration Patient Safety Alert emphasized the need for improved technology for the safe and effective delivery of EFTs.

OBJECTIVE

We investigated the feasibility and safety of ENvue, a novel electromagnetic tracking system (EMTS) to aid qualified operators in the placement of EFT.

METHODS

This is a prospective, single-arm study of patients in intensive care units at two US hospitals who required EFTs. The primary outcome was appropriate placement of EFTs without occurrence of guidance-related adverse events (AEs), as confirmed by both EMTS and radiography. Secondary outcomes were reconfirmation of the EFT tip location at a follow-up visit using the EMTS compared with radiography, tube retrograde migration from initial location and AEs.

RESULTS

Sixty-five patients were included in the intent-to-treat analysis. EFTs were successfully placed in 57 patients. In eight patients, placement was unsuccessful due to anatomic abnormalities. According to both the EMTS and radiography, no lung placements occurred. No pneumothoraces were reported, nor any guidance-related AEs. Precise agreement of tube tip location was achieved between the EMTS evaluations and radiographs for 56 of the 58 (96.5%) successful placements (one patient had two placements). Tube tip location was re-confirmed 12-49 hours after EFT insertion by the EMTS and radiographs in 48 patients (84%). For 43/48 patients (89.5%), full agreement between the EMTS and radiography evaluations was observed. For the five remaining patients, the misalignment between the evaluations was within the gastrointestinal tract. Retrograde migration from the initial location was observed in 4/49 patients (8%).

CONCLUSION

A novel electromagnetic system demonstrated feasibility and safety of real-time and follow-up tracking of EFT placement into the stomach and small intestine, as confirmed by radiographs. No inadvertent placements into the lungs were documented.

LEVEL OF EVIDENCE

Level V (large case series).

Gastrointestinal dysmotility in critically ill patients

Gastrointestinal (GI) motility disorders are commonly present in critical illness. Up to 60% of critically ill patients have been reported to experience GI dysmotility of some form necessitating therapeutic intervention. It has been attributed to various factors, related to both the underlying disease and the therapeutic interventions undertaken. The assessment of motility disturbances can be challenging in critically ill patients, as the available tests used to detect abnormal motility have major limitations in the setting of an Intensive Care Unit. Critically ill patients with GI dysmotility require a multifaceted treatment approach that addresses multiple causes and utilizes multiple pharmacological pathways. In this review, we discuss the pathophysiology, assessment and management of GI dysmotility in critically ill patients.

Gastric Feeding as an Extension of an Established Enteral Nutrition Protocol

BACKGROUND

Indiscriminate gastric feeding in ICU patients imposes unacceptable risks of aspiration. Believing that a subset of ICU patients can be fed safely via the stomach, we have developed a protocol to identify appropriate patients and guide the bedside clinician in how to safely and effectively feed via the stomach.

METHODS

A literature search was done to identify appropriate medical literature. High grade evidence along with local expert opinions were used to develop a protocol. This protocol has been refined and implemented.

RESULTS

Based on perceived risk of aspiration, patients are assigned enteral access (ie, stomach vs. distal post-pyloric). Enteral formula is selected based on patient characteristics. It is then advanced by a standard protocol with specific precautions while monitoring for symptoms of intolerance. Management of intolerance is dictated by the type and severity of intolerance.

CONCLUSION

We have implemented a gastric feeding into a subset of our ICU patients. Gastric feeding requires certain precautions but appears to be safe. With more experience and better understanding of the pathogenesis gastroparesis, we believe that most ICU patients should be able to safely feed into the stomach. This is logistically easier than post-pyloric feeding and offers physiologic advantages.

Nutrition Support in Adult Trauma Patients

Nutrition supplementation is paramount to the care of severely injured patients. Despite its widespread use in trauma patients, many areas of clinical practice remain controversial. The purpose of this paper is to critically review the literature studying the use of enteral vs parenteral nutrition (PN) and to provide the rationale for early enteral nutrition. Additional controversies confronting clinicians are reviewed, including the use of immune-enhancing agents and the optimal site for enteral nutrition delivery (gastric vs small intestinal). Evidence-based recommendations for clinical practice are presented when available.

Gut Motility Issues in Critical Illness

Acute gastrointestinal injury (AGI) is common in critical illness and negatively affects outcome. A variety of definitions have been used to describe AGI, which has led to clinical confusion and hampered comparison of research studies across institutions. An international working group of the European Society of Intensive Care Medicine was convened to standardize definitions for AGI and provide current evidence-based understanding of its pathophysiology and management. This disorder is associated with a wide variety of signs and symptoms and may be difficult to detect, therefore a high index of suspicion is warranted.

Early use of low residue diet is superior to clear liquid diet after elective colorectal surgery: a randomized controlled trial

OBJECTIVE

Compare the feasibility and patient tolerance to either a clear fluid (CF) or low residue diet (LRD) started on postoperative day (POD) 1 after elective colorectal surgery.

BACKGROUND

Diet advancement after surgery traditionally starts gradually with liquids, on the basis of fears that early solid intake may increase nausea, vomiting, and overall complications. A randomized controlled trial comparing LRD and CF on POD 1 was performed.

METHODS

111 elective colorectal surgery patients were randomized to CF (n = 57) or LRD (n = 54). The primary end point was vomiting on POD 2. Secondary endpoints included nausea score, days to flatus, length of hospital stay (LOS), and postoperative morbidity.

RESULTS

Patient characteristics, surgical technique, intraoperative characteristics, and postoperative opioid use were similar between study arms. CF versus LRD results were as follows: POD2 vomiting (28% vs 14%; P = 0.09), and significant increase in mean nausea score (4.7 vs 3.5; P = 0.01), days to flatus (4.8 vs 3.7 days; P = 0.04), and LOS (7.0 vs 5.0 days; P = 0.01). LOS remained significantly shorter even after adjusting for significant covariates (laparoscopic technique, surgical site, postoperative comorbidity, stoma, and nasogastric tube) with LRD patients having an adjusted 1.4-day decrease in LOS (P < 0.01). There was no significant difference in postoperative morbidity between study arms. Multivariate analysis of all secondary endpoints confirmed an overall significant improvement in outcomes for LRD vs CF (P < 0.01).

CONCLUSIONS

LRD, rather than CF, on POD1 after colorectal surgery is associated with less nausea, faster return of bowel function, and a shorter hospital stay without increasing postoperative morbidity.

Nutrition therapy for the critically ill surgical patient with aortic aneurysmal rupture: defining and improving current practice

BACKGROUND

Our goal is to define nutrition therapy in critically ill patients after surgical repair of acute ruptured or dissecting aortic aneurysm to identify opportunities for quality improvement.

METHODS

International, prospective studies in 2007-2009 and 2011 were combined. Sites provided institutional and patient characteristics including from intensive care units (ICUs) admission to ICU discharge for a maximum of 12 days. We selected patients with aortic aneurysmal rupture or acute dissection staying in the ICU for ≥ 3 days.

RESULTS

There were 104 eligible patients from 72 distinct ICUs analyzed. Overall, 86.5% received artificial nutrition. There were 50.0% patients who received enteral nutrition (EN) only, 29.8% patients received a combination of EN and parenteral nutrition (PN), 6.7% patients received PN only, and 13.5% did not receive any nutrition. The mean time from admission to initiation of EN was 3.0 days (SD ± 2.4 days). The adequacy of calories from nutrition support was 46.8% (range 0%-111%) with a mean of 10.0 kcal/kg/day. Of the total of 83 patients who received EN, 53 patients (63.8%) had interruption of EN. The reasons included fasting, intolerance, patients deemed too sick for enteral feeding, and loss of enteral feeding route. For patients with gastrointestinal intolerance, 3/30 patients (10%) received small bowel feeding and 23/30 patients (76.7%) of patients received motility agents.

CONCLUSION

Postoperative critically ill patients with aortic aneurysmal rupture or acute dissection are at high risk for inadequate nutrition therapy, and there may be inadequate utilization of strategies to improve nutrition uptake.

Influence of defunctionalization and mechanical forces on intestinal epithelial wound healing

The influence on mucosal healing of luminal nutrient flow and the forces it creates are poorly understood. We hypothesized that altered deformation and extracellular pressure mediate, in part, the effects of defunctionalization on mucosal healing. We created patent or partially obstructing defunctionalizing jejunal Roux-en-Y anastomoses in rats to investigate mucosal healing in the absence or presence of luminal nutrient flow and measured luminal pressures to document partial obstruction. We used serosal acetic acid to induce ulcers in the proximal, distal, and defunctionalized intestinal segments. After 3 days, we assessed ulcer area, proliferation, and phosphorylated ERK. In vitro, we measured proliferation and migration in Caco-2 and IEC-6 intestinal epithelial cells subjected to cyclic strain, increased extracellular pressure, or strain and pressure together. Defunctionalization of intestine without obstruction reduced phosphorylated ERK, slowed ulcer healing, and inhibited mucosal proliferation. This outcome was blocked by PD-98059. Partial obstruction delayed ulcer healing but stimulated proliferation independently of ERK. In vitro, strain increased Caco-2 and IEC-6 proliferation and reduced migration across collagen but reduced proliferation and increased migration across fibronectin. In contrast, increased pressure and the combination of pressure and strain increased proliferation and reduced migration independently of substrate. PD-98059 reduced basal migration but increased migration under pressure. These results suggest that loss of the repetitive distension may decrease mucosal healing in defunctionalized bowel, while increased luminal pressure above anastomoses or in spastic bowel disease could further inhibit mucosal healing, despite peristaltic repetitive strain. ERK may mediate the effects of repetitive deformation but not the effects of pressure.

Gastrointestinal dysmotility: clinical consequences and management of the critically ill patient

Gastrointestinal dysmotility is a common feature of critical illness, with a number of significant implications that include malnutrition secondary to reduced feed tolerance and absorption, reflux and aspiration resulting in reduced lung function and ventilator-associated pneumonia, bacterial overgrowth and possible translocation causing nosocomial sepsis. Prokinetic agent administration can improve gastric emptying and caloric delivery, but its effect on nutrient absorption and clinical outcomes is, as yet, unclear. Postpyloric delivery of nutrition has not yet been demonstrated to increase caloric intake or improve clinical outcomes.

Altered GI motility in critically Ill patients: current understanding of pathophysiology, clinical impact, and diagnostic approach

Gastrointestinal (GI) motility disturbances are common in critically ill patients. GI tract dysmotility has been linked to increased permeability of intestinal mucosa and bacterial translocation, contributing to systemic inflammatory response syndrome, sepsis, and multiple organ dysfunction syndrome. A key issue in providing nutrition to critically ill patients is intolerance of enteral feeding as a result of impaired GI motility. Remarkable progress has been made in the understanding of the regulation of GI motility in critical illness. Predominant motility abnormalities seen in ICU patients include antral hypomotility, delayed gastric emptying, and reduced migrating motor complexes. The diagnosis of motility disturbances can be challenging to establish in critically ill patients. The available tests used for detection of abnormal motility have major limitations in the ICU setting. Recognition of the type and site of intestinal motility disorder is important to guide the therapy and improve the outcome.

Retroperitoneal repair of abdominal aortic aneurysm reduces bowel dysfunction

OBJECTIVE

To assess the effect of intestinal manipulation and mesenteric traction on gastro-intestinal function and postoperative recovery in patients undergoing abdominal aortic aneurysm (AAA) repair.

METHODS

Thirty-five patients undergoing AAA repair were randomised into 3 groups. Group I (n = 11) had repair via retroperitoneal approach while Group II (n = 12) and Group III (n = 12) were repaired via transperitoneal approach with bowel packed within the peritoneal cavity or exteriorised in a bowel bag respectively. Gastric emptying was measured pre-operatively (day 0), day 1 and day 3 using paracetamol absorption test (PAT) and area under curve (P(AUC)) was calculated. Intestinal permeability was measured using the Lactulose-Mannitol test.

RESULTS

Aneurysm size, operation time and PAT (on day 0 and day 3) were similar in the three groups. On day 1, the P(AUC) was significantly higher in Group I, when compared with Group II and Group III (P = .02). Resumption of diet was also significantly earlier in Group I as compared to Group II and Group III. The intestinal permeability was significantly increased in Group II and Group III at day 1 when compared with day 0, with no significant increase in Group I. Retroperitoneal repair was also associated with significantly shorter intensive care unit (P = .04) and hospital stay (P = .047), when compared with the combined transperitoneal repair group (Group II and III).

CONCLUSION

Retroperitoneal AAA repair minimises intestinal dysfunction and may lead to quicker patient recovery when compared to transperitoneal repair.

Gastric emptying and the organization of antro-duodenal pressures in the critically ill

The motor dysfunctions underlying delayed gastric emptying (GE) in critical illness are poorly defined. Our aim was to characterize the relationship between antro-duodenal (AD) motility and GE in critically ill patients. AD pressures were recorded in 15 mechanically ventilated patients and 10 healthy volunteers for 2 h (i) during fasting, (ii) following an intragastric nutrient bolus with concurrent assessment of GE using the (13)C-octanoate breath test and (iii) during duodenal nutrient infusion. Propagated waves were characterized by length and direction of migration. Critical illness was associated with: (i) slower GE (GEC: 3.47 +/- 0.1 vs 2.99 +/- 0.2; P = 0.046), (ii) fewer antegrade (duodenal: 44%vs 83%, AD: 16%vs 83%; P < 0.001) and more retrograde (duodenal: 46%vs 12%, AD: 38%vs 4%; P < 0.001) waves, (iii) shorter wave propagation (duodenal: 4.7 +/- 0.3 vs 6.0 +/- 0.4 cm; AD: 7.7 +/- 0.6 vs 10.9 +/- 0.9 cm; P = 0.004) and (iv) a close correlation between GE with the percentage of propagated phase 3 waves that were antegrade (r = 0.914, P = 0.03) and retrograde (r = -0.95, P = 0.014). In critical illness, the organization of AD pressure waves is abnormal and associated with slow GE.

A novel technique for post-pyloric feeding tube placement in critically ill patients: a pilot study

Delivery of enteral nutrition in critically ill patients is often hampered by gastric stasis necessitating direct feeding into the small intestine. Current techniques for placement of post-pyloric feeding catheters are complex, time consuming or both, and improvements in feeding tube placement techniques are required. The Cathlocator is a novel device that permits real time localisation of the end of feeding tubes via detection of a magnetic field generated by a small electric current in a coil incorporated in the tip of the tube. We performed a pilot study evaluating the feasibility of the Cathlocator system to guide and evaluate the placement of (1) nasoduodenal feeding tubes, and (2) nasogastric drainage tubes in critically ill patients with feed intolerance due to slow gastric emptying. A prospective study of eight critically ill patients was undertaken in the intensive care unit of a tertiary hospital. The Cathlocator was used to (1) guide the positioning of the tubes post-pylorically and (2) determine whether nasogastric and nasoduodenal tubes were placed correctly. Tube tip position was compared with data obtained by radiology. Data are expressed as median (range). Duodenal tube placement was successful in 7 of 8 patients (insertion time 12.6 min (5.3-34.4)). All nasogastric tube placements were successful (insertion time 3.4 min (0.6-10.0)). The Cathlocator accurately determined the position of both tubes without complication in all cases. The Cathlocator allows placement and location of an enteral feeding tube in real time in critically ill patients with slow gastric emptying. These findings warrant further studies into the application of this technique for placement of post-pyloric feeding tubes.

Early enteral feeding in newborn surgical patients

OBJECTIVE

We report the results of a multicenter prospective trial of early enteral trophic feeding in a group of 56 neonates who required abdominal surgery for a variety of congenital anomalies.

METHODS

In this clinical study, 33 neonates were fed in the early postoperative period (early enteral nutrition [EEN] group), and the remaining 23 (control [C] group) were fasted until resolution of postoperative ileus. Patients in the EEN group (Kocaeli feeding protocol) received 3 to 5 mL of breast milk every hour through a nasogastric feeding tube, starting a mean of 12 h (8 to 20 h) after surgery. The nasogastric tube was clamped for 40 min after each infusion and then opened for drainage. Groups were further divided into two subgroups according to whether an intestinal anastomosis or laparotomy was performed. The change in daily gastric drainage, time to first stool, day of toleration to full oral feeding, and length of hospital stay were compared. Blood bilirubin levels, white blood cell count, and C-reactive protein levels were monitored.

RESULTS

The time to first stool and day of toleration to full oral feeding occurred significantly sooner, whereas nasogastric tube drainage duration and hospital stay were significantly shorter in the EEN-anastomosis group than in the C-anastomosis group. Time to first stool occurred significantly sooner in the EEN-laparotomy group than in the C-laparotomy group, although other parameters did not differ. Neither anastomotic leakage nor dehiscence was observed in any group. There were two cases of wound infection and two of exitus among patients in the C group.

CONCLUSION

Postoperative, early intragastric, small-volume breast milk feeding is well tolerated by newborns. It is a reliable and feasible approach in neonates even in the presence of an intestinal anastomosis after abdominal surgery.

Stimulation of small intestinal burst activity in the postprandial state differentially affects lipid and glucose absorption in healthy adult humans

Small intestinal motor activity is important for the optimal digestion and absorption of nutrients. These motor responses to feeding are frequently abnormal during critical illness, with the persistence of migrating bursts of contractions during enteral feeding. Whether this disturbance influences nutrient absorption is not known. In this study, the effects of small intestinal burst activity on lipid and glucose absorption were evaluated in 10 healthy human adults (6 males, 4 females, 19-47 yr). Upper gastrointestinal manometry was recorded for 6 h during and shortly after a 20-min intravenous infusion of either erythromycin (1 mg/kg), to stimulate burst activity, or saline (0.9%) in a double-blind randomized fashion. Simultaneously with the start of the intravenous infusion, 60 ml liquid feed mixed with 200 microl 13C-triolein and 2 g 3-O-methylglucose (3-OMG) was infused intraduodenally for 30 min. Absorption of lipid and glucose was assessed using the [13C]triolein breath test and plasma concentrations of 3-OMG, respectively. Infusion of erythromycin was followed by a more rapid onset of burst activity following commencement of the duodenal infusion compared with saline (30 +/- 6.1 vs. 58 +/- 10.7 min; P < 0.05). Erythromycin was associated with a slower recovery of 13CO2 (P < 0.01). A positive correlation existed between the time to onset of burst activity and 13CO2 recovery (P < 0.001). Erythromycin had no effect on 3-OMG absorption. In conclusion, stimulation of small intestinal burst activity reduces the rate of lipid absorption but not glucose absorption in healthy human adults.