Total parenteral nutrition in critically ill patients

This report gives a brief about total parenteral nutrition, complications in TPN, components that make up TPN solution, nutritional requirements, as well as the principle for delivering TPN.

Total parenteral nutrition

TPN, which is total parenteral nutrition, is basically feeding the various specialists and highly effective nutritional products to the individual intravenously, thus bypassing the entire process of digestion as well as eating. The patient normally receives the highly complex and efficient nutritional formula, which consists of numerous nutrients like glucose, salts, lipids, and various dietary minerals. The main rationale behind using TPN is to provide the patient with the nutrients that are highly essential for the proper metabolism of the body as well as proper digestion (Elke et al., 2016). It is administered when there is no other route to feed the patient and significant nutrition is not available to them. There is another term, which is partial parenteral nutrition, which is mainly utilized when the nutrition of the patient is partially enteric. The main aim of this nutritional support is to restore as well as prevent the nutritional deficit, ensuring the bowel rest along with supplying with adequate and appropriate caloric intakes well as essential nutrients. This may be administered for short-term or for long-term, depending on the condition of the patient. The main caloric requirements for each patient are generally individualized as per the stress degree, body weight, as well as organ failure. TPN is usually used for the patients who are not able to orally ingest and digest the nutrition. It may be encountered as peripheral parenteral nutrition or through the central line, mainly depending on upion components as well as osmolality (Fivez et al., 2016). Patients that are paralysed or have non-functional GI area are normally administered with TPN. Besides this, the various conditions that require bowel rest, like ulcerative colitis, pancreatitis, and encountering the TPN, become highly essential for ensuring proper bowel movement. It is not only administered to adults, but the children who have immature and destroyed gastrointestinal systems are kept under this medication and are provided with all the nutrition.

Complication in TPN

While the administration of TPN is highly essential to the patients, sometimes there are a range of complications that occur within its administration. These are

Pneumothorax

It generally takes place when the tip of the catheter enters pleural space at the time of insertion; thus, this results in the collapse of the lungs (Blaser et al., 2017). Its main symptoms consist of chest pain, obstructive breathing, breathing sounds, and the cessation of natural chest movement, as well as tachycardia.

The most effective intervention that has been proven to be effective in this is the administration of oxygen. The doctors apply the oxygen and thus notify physician. Doctors insert the chest tube and remove the central line.

Hyperglycemia

This is generally the sudden enhancement within glucose level after the continued malnourished state. Once the starvation is over, glucose intake mainly suppresses the gluconeogenes through the release of insulin as well as suppresses the glycogen. When the person has an excess level of glucose in the body, it often results in hyperglycemia along with osmotic diuresis (Arabi et al., 2015). The excess level of glucose often loads to the lipogenesis and this might result in fatty liver as well as increased production of carbon di oxide. The most effective intervention that the doctors use in this case is monitoring blood sugar on a periodic basis, which is four times a day when the blood sugars are generally stable. Beside this, they follow the agency policy in monitoring of glucose together with TPN.

Components that make up TPN solution

TPN is generally made of two components, which are amino acids, the dextrose solution and solution of lipid emulsion. The solutions are generally categorised as per the patient requirements and sometimes the standardised solutions are also used.

Prepared solutions

The prepared solutions used in TPN contains water as well as electrolytes, amino acids, glucose, essential vitamins, lipids, minerals and some trace elements. The trace elements are mainly added or administered separately. Each and every patient is generally assessed and analysed individually before starting the process of parenteral nutrition. The entire team consisting of specialized doctors, assistants, and nurses generally evaluates the patient and its individual data to make the decision that what PN formula will be used for treatment and what will be the infusion rate (Jimenez, Mehta, & Duggan, 2017).

Added components

Sometimes the single nutrient components are added in order to adjust the contents of body in it. This individual nutrient might be infused separately or sometimes it is injected within the bag consisting nutrient solution as well as intravenous fluids. It is generally found that when patient are administered within the individual component, they become more hazardous in comparison to when they are administered with pre-mixed solution like that employed in TPN. It is due to the fact that the solutions in TPN ate normally balanced when talking about osmolality.

Emulsifiers

The doctors generally takes into account only few emulsifiers for use in parenteral administration and these are limited in number. Among these limited emulsifiers, the most significant and important one that is being used for providing essential nutrients is Lecithin. This is the component that can be easily biodegraded as well as metabolized because it is the integral and import part of the biological membranes. Thus, this makes Lecithin non-toxin and non-poisonous. The other emulsifiers can only be excreted through kidneys, thus creating the toxic lead. The emulsifier which is used for the parenteral nutrition is the purified egg lecithin (Ridley, Gantner, & Pellegrino, 2015).

Nutritional requirements as well as principles for delivering TPN

The TPN is generally delivered through the use of large venous catheter, which is being placed within superior vena cava of the patient through subclavian jugular vein. This is generally done via "cut-down,” but using the modern catheter-system reduces the incidence of the infection and thus shows effectiveness. The therapy of TPN has become well standardized and thus it gives the freedom to the physician to treat patients. Although there are some of the basic principle that the doctors are required to adhere. The ratio and amount of calories to the nitrogen should be appropriate and adequate—100 to 150kcal/g nitrogen. Besides this, two materials should be infused and pervaded simultaneously because there is generally chances of a decrease in nitrogen utilization if infused separately. The entire and overall TPN requirement for entire day should be constructed within hospital pharmacy under the stringent aseptic conditions (Berger & Pichard, C. (2019).

The basic solution of TPN should consist of 20% to 24% of the dextrose along with 3% to more than 4% amino acid. The lipid emulsion is generally the not only significant source of the energy but there should also be the prevention of deficiency of fatty acids. The energy requirements and the components of the energy that need to be inculcated in TPN are calculated by Harris-Benedict equation, which sometimes makes the practice of TPN complicated. The fluid requirements within TPN should be 100mL/kg of the body weight in first 10 kg and 20 mL/kg in next 10 kg. Talking of the calorie requirement, glucose is one of the major carbohydrate that supplies calories. This is generally administered within the solution at 25 to 50%. This is the adequate percentage which provides enough energy to the patients and accomplishes their dietary requirements. Coming on the fat requirements, for overcoming the deficiency of fatty acid, the solution should contain at least 5% of the calories that should be provided as fats.

CONCLUSION