Introduction
One of the body's essential organs is the kidney. Its duties include filtering the plasma and preserving the equilibrium of the electrolytes, acid-base, water, and osmolality. Filtration of water and solutes from plasma into the glomerulus via the afferent arteriole is the first step in urine production. The kidneys also release renin, which controls blood pressure and fluid balance. Moreover, many medications are processed by and excreted from the kidneys. Renal disease is quite common in individuals who need surgery and is linked to a higher risk of unfavorable postoperative results. The risk of surgical complications is increased by even modest renal impairment.
What Are Renal Diseases?
Maintaining fluid and acid-base balance, controlling hemoglobin levels during surgery, and excreting anesthetics and drugs all depend on normal renal function. When there is any renal impairment, it may alter the function of the kidney. The most common renal diseases are
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Acute Renal Impairment: Acute decline in renal function is termed acute kidney injury (AKI) or impairment. It is caused by the decrease in glomerular filtration rate, which prevents the kidneys from excreting nitrogenous wastes and other pollutants. Acute renal injury is also associated with ischemia, nephrotoxins, and renal parenchymal diseases, resulting in multiple organ failures and an increased mortality rate.
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Chronic Renal Impairment: It is characterized by high amounts of urea or creatinine levels in the blood with a decreased glomerular filtration rate or GFR (25 % of the normal rate). When the GFR falls below 10 %, it gives rise to uremic syndrome and end-stage renal disease (ESRD). Moreover, it affects the major function of the kidney involving the elimination of waste products and volume regulation (ECF). The anomalies in the metabolism of calcium, magnesium, and phosphorus are very frequently observed in patients with chronic renal impairment.
What Are the Preoperative Considerations Carried Out in Renal Impairment Patients?
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Due to the renin-angiotensin system, chronic renal failure frequently results in hypertension, which develops peripheral vascular disease and ischemic heart disease.
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Oedema is predisposed to proteinuria and hypoalbuminemia. Pericarditis, autonomic neuropathy, and peripheral neuropathy are also frequently observed with chronic kidney diseases.
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Significant glomerular damage is indicated by proteinuria larger than 150 mg/day, and diabetes mellitus is indicated by glycosuria.
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Serum electrolytes should be monitored, even though they may remain normal until severe renal illness.
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Depending on the severity of the disease and any coexisting conditions, a chest X-ray and an ECG (electrocardiogram) may be necessary.
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In cases of severe renal failure, measurement of arterial blood gasses may show metabolic acidosis as a result of the kidneys' decreased ability to excrete acid.
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Before surgery, hypertension should be maintained with antihypertensives, and urinary infections should be treated with antibiotics. Routine transfusion is not advised with chronic kidney impairment since it increases the risk of CHF (congestive heart failure). In cases of severe renal failure, electrolytes should be properly balanced, and dialysis may be required. Premedicants and antacid prophylaxis may both be recommended.
What Are the Intraoperative Considerations Carried Out in Renal Impairment Patients?
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Due to the patient's placement and laparoscopic surgery, there is an increase in abdominal pressure, necessitating the need for endotracheal intubation.
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Due to chronic renal failure, rapid sequence intubation is favored in patients with gastropathy. Inhalational and intravenous drugs can be used to induce anesthesia. Inhalational agents are used to maintain anesthesia.
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Due to the potential for unexpected bleeding, a large bore intravenous line is necessary. Use of an arteriovenous fistulated limb for intravenous infusions is not advised.
What Are the Anesthetic Considerations in Relation to Renal Diseases?
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Assessment: Fluid administration necessitates central venous pressure assessment with long-term conditions. Additionally, monitoring of temperature is necessary with nephrotic surgery, and the optimal temperature is maintained by warm intravenous fluids and a blanket method.
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Fluid Balance: In order to prevent sudden hypotension during induction, patients with signs and symptoms of dehydration need to receive proper fluid resuscitation. Prevention of hyperkalemia, established by potassium-containing drinks, is avoided in individuals with reduced renal function. For replacing lost blood, colloids and packed red blood cells are used. If there is fluid overflow, dialysis may be deferred for the postoperative phase.
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Renal Barrier: To prevent kidney damage, it may be necessary to administer fluids, dopamine, diuretics, calcium channel blockers, and angiotensin-converting enzyme inhibitors. There is, however, conflicting evidence regarding whether or not any of these therapies can prevent kidney injury. Kidney function can be safeguarded in continuing operations in a number of ways. Although surgery is a significant cause, dehydration, sepsis, hypotension, and the use of nephrotoxic medications are other contributing factors that should be avoided.
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Post-Operative Management: Significant pain is possible, particularly when accessing the kidney is exposed. Early mobilization and the prevention of pulmonary complications following surgery require comprehensive analgesia. In cases of coagulopathy, thrombocytopenia, anticoagulation, or recent hemodialysis, regional analgesia is contraindicated. Non-steroidal anti-inflammatory medicines have a tendency to be nephrotoxic; hence they are contraindicated. Paracetamol is a safe medication and effective adjuvant analgesic.
How to Prevent Acute Renal Failure in Anesthetic Patients?
The two most crucial elements in preventing acute renal failure are the maintenance of normovolaemic and appropriate renal perfusion pressure. If necessary, central venous pressure monitoring should be used to guide adequate hydration. Eventually, urine output should be monitored hourly and kept at or above 1 ml per kilogram per hour. Vasoactive drugs play a vital role in maintaining arterial blood pressure appropriately once the patient has been adequately resuscitated with fluid. Following proper hydration and blood pressure regulation, Furosemide (maximum dose of 240mg) is advised intravenously in oliguric conditions (urine output 0.5 ml/kg/hr). Further administration of Furosemide is ineffective if no diuresis develops. Comparatively, Furosemide is preferable because Mannitol and Dopamine enhance urine production and raise the kidneys' oxygen requirements.
Conclusion
Attending anesthesiologists face challenges when treating patients with renal disease or insufficiency. The prevention of additional renal injury necessitates adequate fluid management, maintenance of normovolemic, and avoidance of hypotension and hypertension. The anesthesiologists caring for such patients must comprehend how to treat them and take action to stop future renal harm during the perioperative phase. Even during the perioperative period, electrolytes like potassium, sodium, and bicarbonate must be monitored daily. After surgery, it is crucial to start getting enough calories as soon as possible.
