Paediatric Urology

25. PERIOPERATIVE MANAGEMENT

25.1. Preoperative fasting, intraoperative fluid therapy, postoperative feeding, fasting and fluid management

25.1.1. Epidemiology, aetiology and pathophysiology

Children have a different total body fluid distribution, renal physiology and electrolyte requirements, as well as weaker cardiovascular compensation mechanisms compared to adults [1459]. During development, children have a high metabolic rate and lower fat and nutrient stores, which means they are more susceptible to metabolic disturbances caused by surgical stress [1460]. The metabolic response to anaesthesia and surgery in infants and children is related to the severity of the operation [1461].

25.1.2. Disease management

25.1.2.a. Preoperative fasting

Preoperative fasting has been advocated for elective surgery to avoid the complications associated with pulmonary aspiration during induction of anaesthesia. New regimens include a one-hour limitation for clear liquids [1462,1463] without increased risk of pulmonary aspiration [1464]. Several studies have shown that fasting times in clinical practice often exceed the Guidelines with average fasting times of six to ten hours [1463-1465]. Compared to adults, children have a higher metabolic rate and low glycogen stores and impaired gluconeogenesis, which makes hypoglycaemia an important issue to consider, especially in children < 36 months old [1463]. Therefore, it is important to prevent extended fasting times. Clear-liquid carbohydrate drinks have been proposed to reduce these fasting times [1466]. The presence of Type I diabetes does not necessitate different fasting instructions from those for healthy children [1467]. Depending on the length and scale of the procedure, special attention to appropriate insulin administration, management of hypo- and hyperglycaemia, as well as other metabolic abnormalities, is required [1468].

Table 12 provides the current guidelines for preoperative fasting for elective surgery [1467].

Table 12: Preoperative fasting times for elective surgery

25.1.2.b. Maintenance therapy and intraoperative fluid therapy

The goal of intraoperative fluid management is to sustain homeostasis by providing the appropriate amount of parenteral fluid. This maintains adequate intravascular volume, cardiac output, and oxygen delivery to tissues at a time when normal physiological functions have been altered by surgical stress and anaesthetic agents.

The main goal of intraoperative fluid management is to maintain a normal extracellular fluid volume (EFV). During the intraoperative period, fluid deficits may be induced by preoperative fasting, blood loss or third-space losses.

25.1.2.c. Postoperative feeding, fasting and fluid management

Checking serum chemistry after uncomplicated surgery is not mandatory in children with normal preoperative renal and hepatic function. However, if oral intake has been postponed for > 24 hours (e.g. as in intestinal surgery), there is an increased risk of electrolyte abnormalities, requiring further assessment and subsequent management, particularly with potassium. Postoperative findings, such as decreased bowel movements and ileus, may be signs of hypokalaemia.

Children who undergo interventions to relieve any kind of obstructive diseases deserve particular attention, especially due to the risk of polyuria as a result of post-obstructive diuresis [1469]. In children who develop polyuria, it is important to monitor fluid intake and urine output, as well as renal function and serum electrolytes. If necessary, clinicians should not hesitate in consulting with a paediatric nephrologist.

In children who have undergone nonabdominal surgery, studies have suggested that gastric motility returns to normal one hour after emergence from anaesthesia [1470]. Early postoperative intake of fluid in children who have undergone minor or nonabdominal urological surgery is associated with reduced postoperative vomiting and lower opioid use [1471] and is therefore encouraged.

Intraperitoneal surgery and the use of bowel may lead to decreased bowel motility in the postoperative period, which can lead to paralytic ileus. Experimental and clinical studies have shown that traditional restriction of oral intake after abdominal surgery has no basis in scientific evidence and adverse effect on tissue regeneration and enzymatic function has been reported. Due to those deleterious effects of fasting, early enteral nutrition is preferred to parenteral nutrition [1472]. In newborns, early intragastric, small-volume breast is well tolerated in the postoperative period and seems to provide a trophic effect on gut mucosa [1472].

Chewing gum is a type of sham feeding that promotes intestinal motility by means of cephalic-vagal stimulation. Chewing gum is usually well-tolerated and accepted by older children without any contraindication. Although the evidence is limited, it can potentially enhance bowel recovery in the postoperative period in children [1473].

The ERAS protocol is a patient-centred, multimodal approach to optimise postoperative recovery. This protocol includes pre- and intraoperative element, such as minimal preoperative fasting and careful intraoperative fluid management and focuses on postoperative care. The postoperative ERAS protocol suggests starting clear fluid intake on the evening of surgery and a normal diet the day after surgery and thereby early discontinuation of IV fluids. Further focus is on early mobilisation, preventing epidurals and omitting or early removal of external tubes [1474].

The implementation of an ERAS protocol has resulted in a shorter length of hospital stays, faster bowel recovery and reduced need for postoperative, opioid-free administration [1474,1475]. The implementation of ERAS protocols does not seem to result in higher complication and readmission rates. Instead, some studies have even demonstrated a significant reduction in complication occurrence [1474]. When implementing ERAS in children with neurological abnormalities, special attention should be given to bowel management, with preoperative treatment of constipation and early postoperative continuation of routine bowel management.

25.1.3. Summary of evidence and recommendations for the management of perioperative fluid management

25.2. Postoperative pain management: general information

25.2.1. Epidemiology, aetiology and pathophysiology

The provision of adequate pain control requires proper pain evaluation, accurate choice of drug and route of administration, as well as consideration of age, physical condition and type of surgery and anaesthesia [1476].

25.2.2. Diagnostic evaluation

Assessment of pain is the first step in pain management. Several pain assessment tools have been validated according to the child’s age, cultural background, mental status, communication skills and physiological reactions [1477]. Depending on the child’s age, the 0-10 numeric rating scale; Faces Pain Scale - Revised (FPS-R); Face Legs Activity, Cry and Consolability (FLACC) scale; or Colour Analog Scale (CAS) can be used [1478]. One of the most important topics in paediatric pain management is informing and involving the child and caregivers during this process. Patient and family-controlled analgesia is the preferred pain management in the hospital and at home if the child and caregivers are provided with the correct information [1479,1480].

25.2.3. Disease management

25.2.3.a. Drugs and route of administration

Pre-emptive analgesia is an important concept that aims to induce the suppression of pain before neural hypersensitisation occurs [1481]. Regional anaesthesia is given intraoperatively, which can include a regional nerve block or local wound infiltration and has proven to reduce the need for postoperative analgesia [412]. The WHO’s ‘pain ladder’ is a useful tool for the pain management strategy [1482]. Paracetamol and nonsteroidal anti-inflammatory drugs (NSAIDs) are the first choice. As they become insufficient to prevent pain, weak and strong opioids are added to oral drugs to achieve balanced analgesia. A proposed strategy for postoperative analgesia may be as follows:

1. intraoperative regional block and/or local wound infiltration;
2. paracetamol + NSAID;
3. paracetamol + NSAID + weak opioid (e.g. tramadol or codeine); and
4. paracetamol + NSAID + strong opioid (e.g. morphine, fentanyl, oxycodone or pethidine).

The use of opioids in children has long held a standard role in the postoperative management of pain. Increased recognition of the adverse effects of opioids and prolonged opioid dependency demand a balanced intraoperative administration of opioids [1483]. Intraoperative adequate dosage of paracetamol and NSAIDs results in a decrease in opioid requirement in children [1484,1485].

25.2.3.b. Circumcision

Circumcision requires anaesthesia and proper pain management [1486]. Potential analgesic interventions during circumcision include the use of a dorsal penile nerve block (DPNB) or ring block, topical anaesthetics (depending on age, weight and body surface), and sucrose, preferably in combination [412,1487]. Caudal blockade methods have similar efficacy compared to DPNB [1488]. However, caregivers should be informed about the more-frequent incidence of postoperative motor weakness and micturition problems [1487,1488].

25.2.3.c. Penile, inguinal and scrotal surgery

Caudal blocks and peripheral nerve blocks (DPNB and pudendal) are commonly used methods for analgesia in hypospadias surgery. Several agents with various doses, concentrations and administration techniques have been used. All have been shown to have adequate postoperative analgesic properties, and no increase in postoperative complications was seen [411-413]. Severe bladder spasms caused by the presence of the bladder catheter can be managed with antimuscarinic medications.

For inguinoscrotal surgery, various regional anaesthesia methods have been investigated, such as transversus abdominis plane block, quadratus lumborum nerve block, ilioinguinal/iliohypogastric nerve blocks and caudal blocks. All of these methods have been shown to have adequate postoperative analgesic properties [1489]. In addition, local anaesthetics such as clonidine or dexmedetomidine have been shown to prolong the analgesic effect [1490,1491].

25.2.3.d. Bladder and kidney surgery

Continuous local infusion (pain catheter) has been shown to be effective and reduces the need for postoperative opioids [1492-1494], as well as systemic (intravenous) application of analgesics [1495]. Ketorolac (NSAID) is an effective agent that decreases the frequency and severity of bladder spasms, the length of postoperative hospital stay and costs, and intraoperative opioid administration [1496]. Open kidney surgery is particularly painful, because all three muscle layers are cut during conventional flank incision. A dorsal lumbotomy incision may be a good alternative in small children because of the shorter postoperative hospital stay and earlier return to oral intake and unrestricted daily activity [1497]. Caudal and paravertebral blocks continuous epidural analgesia, as well as rectus sheath and transversus abdominis plane blocks, have been shown to decrease post-operative morphine requirement after abdominal and renal surgery [1498-1500].

25.2.4. Summary of evidence and recommendations for the management of post-operative pain

25.3. Antibiotics management: general information

It is well established that perioperative antibiotics prevent infections following surgery, but limited data are available for antibiotic management in paediatric genitourinary procedures. Antibiotic prophylaxis carried the risk of developing drug-resistant bacteria and adverse effects such as allergic reactions. Moreover, in childhood, some antibiotics are not recommended, and their use is discouraged except for in severe cases.

In 2020 Snyder et al. conducted one of the first systematic reviews on perioperative antibiotic practices in the paediatric urology literature [1501]. They reported that the majority of the articles did not provide accurate information on perioperative antibiotic practices. Other studies demonstrated wide variations in practice patterns for antibiotic usage among paediatric urologists [407,1502].

Perioperative prophylactic antibiotics in hypospadias repair have been widely debated in the literature. A meta-analysis demonstrated a high risk of bias and a low level of evidence in terms of postoperative prophylactic antibiotics preventing complications following hypospadias repair [410]. On the contrary, a consensus exists for no perioperative antibiotics following circumcision [1501].

A prospective, randomised, controlled, non-blinded, non-placebo study was performed on the effectiveness of continuous antibiotic prophylaxis in patients with JJ stents, with a total of 105 patients. They concluded that continuous antibiotic prophylaxis reduced the incidence of febrile UTIs, particularly in children with a history of febrile UTI and LUTS [1503].

There is a need for standardisation of perioperative antibiotic usage for paediatric urological operations. However, a lack of prospective studies and RCT’s are the main barriers for creating evidence-based guidelines on this particular topic.

25.4. Thromboprophylaxis management: general information

Thromboprophylaxis in children involves preventive measures aimed at reducing the risk of blood clot formation. Unlike adults, most children do not require thromboprophylaxis after surgery. It is only considered in certain high-risk situations such as underlying medical conditions like malignancies, congenital heart disease and so on. Moreover, very limited data are available on the safety and efficacy of anticoagulants in paediatric practice.

25.4.1. Epidemiology, aetiology, pathophysiology

The incidence of venous thromboembolism (VTE) in children is low but has increased due to an increased use of central venous catheters (CVL) and an improvement in detection [1504]. Some authors suggest an incidence of five to eight cases of symptomatic VTE per 10,000 hospital admissions (0.05%-0.08%), but the true incidence may be higher as the majority of VTEs are clinically silent in children [1505]. In infants, VTE is most often associated with sepsis, congenital haematological disorders and malignancies. At adolescence, the physiology of the coagulation system matures and additional risk factors such as smoking, obesity, pregnancy and oestrogen-containing oral contraceptives become relevant. There is a 2:1 preponderance of females among adolescents who develop VTE.

The risk of VTE after urological surgery has been shown to have an incidence of 0.12%, which increases to 0.2% for prolonged hospitalisation [1506,1507].

Before adolescence, the absolute risk of VTE following major surgery, trauma, or immobilisation is low, even in children who have thrombophilia [1508]. Therefore, thromboprophylaxis is not recommended.

The risk of developing VTE should focus on adolescents (> 13 years) particularly those with one or more risk factors, such as those mentioned above [1509].

General preventive measures are fundamental to prevent VTE and should include: adequate peri- and postoperative hydration, early mobilisation after surgery and removal of CVLs as soon as possible. In post-pubertal girls undergoing any kind of surgery, consideration should be given to withholding the combined contraceptive pill for four weeks prior to planned surgery, particularly if there is a strong family history of thrombosis or a known thrombophilic risk factor [1505].

25.4.2. Diagnostic evaluation

Identifying thrombophilic risk factors in the family and patient history is important. Symptoms are similar to adult patients with pain, oedema of the dependent areas and development of collateral vessel circulation. However, children with VTE also have some unique presentations, such as purpura fulminans. As with adults, the diagnosis of VTE in the upper venous system is confirmed using doppler US and, if necessary, with venography. However, the optimal diagnostic test for lower limb VTE and pulmonary embolism in children is undefined at the present time, but US is the first approach [1510].

25.4.3. Disease management

The aims of antithrombotic therapy in children are similar to those for adults with VTE. Management of childhood VTE is often complex, due to the frequent coexistence of medical and surgical diseases, and the fact that limited data is available on the efficacy and safety of these drugs in paediatric practice. A multidisciplinary management approach should be sought.

Medical device and physiological mechanism for thromboprophylaxis
Physical treatments for thromboprophylaxis are the same used for adult patients: graduated compression stockings (GCS), intermittent pneumatic compression (IPC) devices and venous foot-pumps (VFPs). No paediatric sizes of GCS or IPC are yet available, therefore, they are applicable only to older patients - usually those over 40kg in weight or older than thirteen years. Intermittent pneumatic compression devices have been used for intraoperative use in children aged thirteen years and over who weigh > 40kg and who are expected to undergo prolonged surgery [1505,1509].

The evidence for the use of these devices is significantly less than for anticoagulant options and few data are available in children and adolescents [1511]. These devices should be combined with pharmacological prophylaxis. Early mobilisation and good hydration should be encouraged in patients of all ages.

25.4.4. Pharmacological treatment for thromboprophylaxis

The use of anticoagulant agents to prevent VTE is very limited in children. None of the preparations are licensed in the paediatric age group. Low molecular weight heparins (LMWHs) have become the mainstay anticoagulant in the paediatric population, both for prophylaxis and treatment due to the more predictable pharmacokinetics compared with unfractionated heparin. Low molecular weight heparins allow less-frequent monitoring and have a lower incidence of serious side effects. Compared with adult patients, children require higher doses of LMWH, which decrease with age due to a decreased thrombin production and a high renal clearance. The most commonly used drugs are enoxaparin and dalteparin, and the major bleeding rate for prophylactic use of LMWH is low [1505,1509,1512].

Children older than 13 years with multiple risk factors for thrombosis should be considered for thromboprophylaxis with LMWH, particularly if immobilisation for more than 48 hours is expected [1512].

25.4.5. Prevention of CVL-related VTE

The presence of a CVL is the most significant risk factor for VTE in children. Central venous catheters placed in the right internal jugular seem to be associated with a lower risk of VTE. There is also evidence that femoral CVLs are associated with a particularly high risk for thrombosis in children [1505].

Thromboprophylaxis did not prevent CVL-related VTE both in prospective studies and RCTs, because most of these thrombi were transient and resolved spontaneously without therapy [1513].

25.4.6. Summary of evidence and recommendations for the management of thromboprophylaxis management

25.5. Premedication management: general information

Most children undergoing anaesthesia and surgery develop anxiety that could lead to adverse reactions. Many factors may influence preoperative anxiety [1514]. Anxiety and distress can be prevented or relieved, combining premedication, distraction techniques and parental or caregivers’ presence. Nonpharmacological, age-appropriate methods, such as play therapy, toys, storybooks, videos, tablet and mobile phone can all be useful. A successful plan must therefore take into account the age and temperament of the child [1515].

The most important goal of premedication is to alleviate patients’ anxiety and facilitate a smooth separation of the child from their parents/caregivers. Preanaesthetic sedatives in children must be given in a timely fashion preoperatively, and include midazolam, clonidine, ketamine and dexmedetomidine, but no consensus has been reached on the best choice against preoperative anxiety. Clinicians should select the appropriate premedication depending on the patient’s age, disease and psychological status [1516].

Topical anaesthesia should be used to reduce or eliminate the pain and anxiety of an intravenous access placement when an intravenous induction is required. The most commonly used local anaesthetic creams require 20 to 60 minutes for maximal effect, but they can cause vasoconstriction that could make the vein harder to see and cannulate [1514,1516].

25.5.1. Recommendations for premedication management: general recommendations