Severe abdominal trauma, abdominal infection, severe acute pancreatitis, retroperitoneal hematoma and other reasons lead to a continuous increase in abdominal cavity pressure, and surgical patients are unable to close the abdominal cavity at normal pressure. At this time, forced closure of the abdomen or continued increase in abdominal pressure in patients without surgery can cause a series of pathophysiological changes in the body, increased respiratory resistance, reduced cardiac output, acute renal failure and other clinical syndromes, known as Abdominal compartment syndrome (ACS), the mortality rate can be as high as 40-60%, the use of open abdomen (open abdomen, laparotomy) is an important tool in the rescue and treatment of patients with ACS. The use of open abdomen (laparotomy) is an important tool in the treatment of ACS patients.
Patients with open abdomen have reduced abdominal pressure, but the body is in high metabolism and high catabolism, increased lean body and protein consumption, decreased immune function, and delayed wound healing, so how to implement effective nutritional support during the long and dangerous course of the disease is directly related to patient survival. Patients with open abdominal cavity are capable of parenteral nutrition (Total parenteral nutrition, TPN), but long-term application of TPN brings metabolic and infectious complications and significantly increases costs, EN (Enteral nutrition, EN) is safe and effective in accordance with physiology, and therefore is the preferred nutritional support treatment for critical illness [4-5]. However, patients with open abdominal cavity have intestinal dysfunction such as chronic exposure of the intestinal canal with intestinal wall edema, reduced intestinal blood flow and slowed intestinal peristalsis, and it is questionable whether EN can be tolerated and effectively improve the nutritional status of patients and when it should be applied. In this study, we retrospectively observed the implementation of EN in 21 patients who underwent laparotomy for ACS (severe acute pancreatitis, abdominal trauma) to evaluate the safety and efficacy of EN in these patients.
Materials and methods
1. patient data.
We retrospectively observed patients admitted to our department from January 2003 to November 2006 who underwent laparotomy for ACS (severe acute pancreatitis, abdominal trauma), of which those who used EN for more than 3 days were entered into the study, a total of 21 patients, 3 of whom continued EN after suspension (2.8±1.3 days) due to surgical removal of abdominal gauze filling, and 2 of whom developed enterocutaneous fistulae and continued EN using effective drainage (3.5±2.2 The EN was continued after the use of effective drainage (3.5±2.2 days).
2. EN route and tube placement method.
Transjejunal nutrition support was used in all 21 patients. A nasojejunal nutrition tube (3 cases, 14%) was placed using endoscopic guidance (4 cases, 19%) or with X-ray assistance (Florcare nutrition tube, no.), and a surgical jejunostomy (14 cases, 67%) was performed (silicone nutrition tube, no.), respectively. After placement of all tubes, the tip of the tube had to be confirmed to be in the jejunum under X-ray before EN support could be started.
3. EN support protocol.
All patients were covered with polypropylene mesh after the abdominal cavity was opened, and the timing of starting EN was decided according to the recovery of intestinal function, infection control, decreasing edema, and the emergence of peristalsis in the exposed intestinal tube; saline was used as the first nutritional preparation at the beginning of EN, and if intestinal edema was reduced by using mannitol, saline infusion was started; after it was well tolerated, pre-digested element nutrition was given, which was formulated into different concentrations from When the intestinal function recovers well, use the whole protein EN preparation containing dietary fiber to meet the needs of the body.
4. EN infusion method.
Continuous infusion by EN infusion pump, 18-20h infusion per day, infusion rate starts from 10ml/h, and gradually increase the infusion rate according to the patient’s intestinal tolerance until the target amount is reached.
5. Observation indicators.
(1), target volume: The actual energy consumption and respiratory quotient of patients were measured using the HB formula and stress factor calculations in disease and treatment situations or indirect energy meters to clarify the energy target volume of patients. The amount of protein given was 1.8-2.0 g/kg/d. The time from the start of EN to the closure of the abdominal cavity after TAC and the final dose achieved by the patient were recorded.
(2), Nutritional index testing: blood total protein, albumin, prealbumin, transferrin and fibronectin levels were measured before the start of EN, during treatment and at the end (Hitachi 7500 automatic biochemical analyzer). 10 patients (48%) were tested for changes in nitrogen balance (Kjeldahl nitrogen meter).
(3), EN-related complications monitoring: during EN, bedside monitoring of patients’ diarrhea (watery stool, 500 ml/d, more than 2 times a day); gastric reflux (30 min gastric fluid volume more than 200 ml); frequency of nausea, vomiting and abdominal distension.
Results
1. General information.
A total of 21 cases were enrolled, 19 males and 2 females, aged 14-68 years, with APACHEII scores of 8-15, and the disease types are shown in Table 1. Three of the cases had one interruption of EN due to removal of the abdominal gauze, and two cases had intestinal fistulas after TAC and continued EN after using effective drainage. 91% survival rate in this group of patients.
2. EN implementation.
The number of hospital days in 21 patients was 99.6±46.8 days, and the total time of EN implementation was 51.5±33.6 days, with EN starting 8.8±5.5 days after the abdominal cavity was opened. While the abdominal cavity was still open, actual energy expenditure was detected using indirect energy meters in 10 cases (47%), and EN achieved 93% of the target caloric value (80-105%). The actual energy expenditure was calculated according to the HB formula plus stress factor correction, and the EN reached 95% (83-100%) of the target calories in the other 11 patients. Calculated protein amount was given according to 1.8-2.0g/kg/d, and the conventional EN formula could not meet part of the nitrogen plus supplemented with protein powder, with a heat to nitrogen ratio of 100kcal: 1g.
3, nutritional indicators monitoring.
(1), nitrogen balance: 10 of the patients (47%) retained urine, feces, abdominal drainage fluid, abdominal washout fluid were detected nitrogen amount, and the calculated nitrogen balance result was -30.4±4.5g/d.
(2), Protein index: 21 patients had total blood protein, albumin, prealbumin, transferrin, and fibronectin levels before and after the use of EN.
4. EN complications.
During EN in 21 patients, there was no occurrence of catheter-related complications in 1 case. The incidence of diarrhea was 14 cases (67%), no 1 case was diarrhea caused by Clostridium difficile, which was considered to be related to intestinal wall edema, dysbiosis due to antibiotic use, etc. All of them were resolved by adjusting the flora with Pefixan (Bifidobacterium and Lactobacillus), reducing intestinal edema with mannitol or albumin, and reducing intestinal peristalsis with compound phenylephrine or emmenagogue. Gastric reflux occurred in 5 cases (23%) and was reduced by adjusting the patient’s position (head height 30 degrees), morpholine, and Gastrodin to increase gastrointestinal motility after bedside X-ray determined that the nutritional feeding tube was in place. Vomiting was relieved in 2 cases (9.5%) by slowing EN infusion and intramuscular gastrofluidic injection. In 5 cases (23%), the symptoms improved by adjusting the EN infusion rate and enema measures, and EN support was continued.
DISCUSSION
Patients with ACS undergoing abdominal opening have complex conditions and long duration of illness, and nutritional support becomes an important treatment as well as fluid resuscitation, antibiotics, and wound care. These patients are in a hypermetabolic state, with increased metabolism after the first surgery, peaking at 24 h. There is often a “second strike” of reoperation and infection, with a significant increase in actual energy expenditure. EN can provide nutrition, maintain the intestinal barrier, reduce stress, and reduce the incidence of infection, and some studies have shown that providing 15-30% of the target amount is sufficient to maintain the body’s immune function. The implementation of EN is therefore an important means of interrupting this vicious cycle [4-6], but the implementation of EN in patients with open abdominal cavity faces three challenges. One is the establishment of the EN pathway, especially transjejunal nutrition, the second is whether the intestine can apply EN, and the third is to achieve the target amount needed by the patient.
Currently, the establishment of a transjejunal nutrition feeding tube is mainly done through surgical placement, endoscopically guided or X-ray assisted placement, with the tip identified to start EN after jejunum. 21 patients enrolled in the group started EN approximately 8 days after laparotomy, due to the fact that these patients often face postoperative hemodynamic instability, resuscitation, and blood loss, and vasoactive drug use and early excessive fluid resuscitation can lead to visceral ischemia and tissue edema, affecting the recovery of intestinal motility and absorption function, so the start time of EN is significantly prolonged, while the infusion rate gradually increases from 10 ml/h and takes longer to reach the target volume. Compared with ordinary critically ill patients who can start EN within 72 h postoperatively and reach the full volume in 48-72 h, the start time of EN in patients with open abdomen is late and the time to reach the full volume is significantly prolonged. This is determined by the disease characteristics and treatment process. Primary diseases such as bowel resection and bowel wall edema lead to a significantly slower rise in EN, unstable disease such as endostasis imbalance, and treatment measures during the course of the disease such as abdominal irrigation, gauze removal, and skin implants affect the process of reaching full volume of EN. However, the patient was able to significantly reduce the abdominal pressure after the open polypropylene mesh covering the exposed intestinal canal, and EN could be started once the intra-abdominal pressure was lower than 25 cmH2O and the pathophysiological process was improved, while dehydration such as mannitol and CRRT was used to reduce intestinal wall edema and promote early recovery of intestinal dynamics.The study was based on the hemodynamic, organ function and metabolic changes in TAC patients, intestinal dynamics and the recovery of absorption function, careful bedside observation, patient increase of speed dose, timely nutritional re-evaluation to adjust the nutritional program, first PN and EN combined to ensure the amount of nutrition provided, and then EN made this group of patients all achieve the target amount of treatment, that is, more than 90% of the actual caloric and protein requirements, significantly higher than a group of 14 foreign patients with open abdomen achieved the target amount of 77%. Of course this group of patients took longer to implement EN [7], suggesting that the longer the TAC patients receive EN during the implementation of nutritional support, the more likely it is that the nutritional target amount required by the treated patients will be achieved, while the time between the start of EN and reaching the full amount can be significantly reduced in patients after appropriate therapeutic interventions, which is related to the deeper understanding of the pathophysiological process of the disease itself and the progress of treatment.
Nitrogen balance and plasma protein levels are important indicators to monitor the effectiveness of nutritional support in patients when there is a large open abdominal wound, a huge reservoir of fluid, electrolytes and proteins, with significant loss of nutrients. There were 10 patients monitored with a nitrogen balance -30.4±4.5 g/d, which is significantly higher than in another group of studies -15±9.7 g/d (urinary nitrogen only) [7-8]. It is suggested that the loss of nitrogen from the body is significantly increased after opening the abdomen and is in a significant negative nitrogen balance, therefore, the nitrogen level was increased in the nutritional support regimen of this group of patients, and all patients had different degrees of improvement in plasma protein after treatment. Albumin has a half-life of 21 days, is influenced by exogenous factors, and does not reflect changes in the nutritional status of patients well in the short term, but the increase in albumin after EN in patients with open abdominal cavity is related to the longer duration of their nutritional support. While prealbumin, transferrin and fibronectin, which decreased significantly after stress such as trauma or surgery, were below normal values before treatment, all three improved after EN support despite changes during treatment, with fibronectin increasing significantly, suggesting improvement in the patient’s nutritional status. In addition, the higher incidence of diarrhea in EN support has multiple causes. Antibiotics are commonly used in critically ill patients, altering the normal flora of the intestine leading to diarrhea, and after starting nutritional therapy, all were supplemented with pepcid to adjust the intestinal flora, which reduced the incidence of diarrhea to some extent. Other factors of intestinal infection causing diarrhea were improved by the use of non-absorbable intestinal antibiotics. The use of hyperosmolar preparations such as mannitol, lactose intolerance, nutrient preparation intolerance, malabsorption, and rapid intestinal peristalsis can cause diarrhea, which can be addressed by changing the formulation of nutrient preparations (increasing dietary fiber or removing lactose), heating the nutrient solution, reducing excessive rapid intestinal peristalsis, removing the laxative component of nasal medications, and slowing the rate of nutrient infusion.
Nutritional support is important in complex surgical major and critically ill patients, especially those with TAC. Early EN is beneficial, but patients with open abdominal cavity should determine the appropriate time to start adaptation of EN according to organ function and metabolic changes, and should not be obsessed with early EN. By establishing a suitable enteral feeding route, careful observation and close monitoring during treatment, and timely adjustment of the nutritional regimen, the target amount required for patient treatment can be achieved and metabolic and surgical complications can be reduced. After clinical application in this group of patients, the intestinal canal of patients with open abdominal cavity, although exposed, was protected from damage when the infection was controlled, plus the polypropylene mesh coverage. At the same time, the timely administration of EN intestinal mucosa and intestinal wall tissues were improved nutrition and circulation, so that the tissue repair function tends to be healthy. Therefore, EN can be safely and effectively applied to patients with open intestinal canal exenteration in the abdomen, improving prognosis and reducing costs, and is an important and feasible treatment measure.