31. A Selection of Clinical Scenarios
KeywordsTransfusion trigger infantLaparoscopic appendicectomyAnesthesiaConsent for procedures in minorsMuscular dystrophyAnesthesiaAnesthesia for inhaled foreign bodies
This chapter contains several hypothetical clinical situations that are discussed in detail to show some management options and why one option might be better than others. It will also be useful for readers preparing for the short answer question section of the exams. Although the questions are answered in an exam style, the answers are longer than would be expected in the usual short-answer format, and not every detail would be needed to score well in an exam.
31.1 An 8 Month Old, 10 kg Infant Presents for Laparotomy After a Failed Attempt at Reducing an Intussusception with a Barium Enema
Describe and justify your perioperative fluid management
These infants are often unwell and hypovolemic from vomiting, bowel losses and rectal bleeding, and may be septicemic. Hypotension at induction is a concern, and I would ensure the infant has received 10–30 mL/kg of 0.9% saline or Hartmanns (CSL) fluid during resuscitation before induction. The response to every bolus would be assessed to guide further fluid resuscitation. 5–10 mL/kg fluid boluses could be given over 15–30 min using an infusion pump if available or by manually infusing using a three-way tap and 10 mL syringe as a ‘piston-pump’ (see Chap. 5, Sect. 5.4.4).
During anesthesia and surgery, any blood or fluid loss would be replaced with isotonic fluid such as Hartmanns. Ongoing maintenance fluid for a laparotomy is around 10 mL/kg/h, and this would be given in addition to any losses. Fluid status would be assessed by monitoring heart rate, BP, urine output, the plethysmographic or arterial trace variation with ventilation and arterial blood gases to monitor the pH, bicarbonate and lactate concentrations. The hemoglobin level would also be regularly measured, and the decision to transfuse dependent on (i) hemoglobin concentration, (ii) the likelihood of further blood loss during surgery, and (iii) the infant’s cardiovascular stability. This infant does not need any glucose intraoperatively because gluconeogenesis is effective in an infant of this age and surgical stress is likely to trigger a hyperglycemic response.
Post operatively, the infant will have no oral intake. The basic maintenance rate for IV fluids for this infant is 4 mL/kg/h, or 40 mL/h. Although there is likely to be an increase in ADH secretion and fluid retention postoperatively, there will also be extravascular space losses into the peritoneal cavity, and possibly blood loss. It would therefore be reasonable to increase the maintenance rate to 50 mL/h to allow for this and frequently assess fluid status based on observations, urine output and peripheral perfusion. The infant will need glucose postoperatively while fasting. A suitable fluid needs to be a salt-rich isotonic fluid containing glucose, such as 5% dextrose with saline 0.9%. Hypotonic fluids such as 2.5% dextrose with 0.45% saline may cause hyponatremia and should be avoided in this clinical scenario. Daily measurement of plasma electrolytes will be needed while the infant is on IV fluids.
At the completion of surgery, the hemoglobin is measured at 70 g/L. Would you transfuse this infant?
This is a low hemoglobin, and around the ‘transfusion trigger’ for children of 70–80 g/L. If the infant was previously well without cardiorespiratory disease, has stable blood pressure, pulse, respiratory rate and perfusion with urine output 10 mL/h and no ongoing blood loss, transfusion can be avoided. The Hb needs to be measured regularly to ensure it is not falling.
In what circumstances would it be reasonable to provide continuous epidural analgesia for postoperative pain relief in this child?
Epidural analgesia would be reasonable if the infant does not appear septic and has stable observations. The anesthetist must be trained and skilled at epidural insertion in smaller infants and postoperative ward staff must be trained and familiar with the management of epidurals in infants.
31.1.1 Further Commentary
Part (i) of the question asks only about perioperative fluid management. In an exam, no marks would be scored for mentioning induction technique. If it had been asked however, induction would include the fluid boluses discussed above, a modified rapid sequence induction, and a technique to prevent hypotension at induction. Such a technique might be fentanyl 1–2 μg/kg, allowing time for this to take effect to reduce the induction dose of propofol to about 2 mg/kg, or using ketamine 1–2 mg/kg for induction.
31.2 A Girl Who Has Just Turned 9 Years Old and Weighs 26 kg Is Scheduled for Laparoscopic Appendicectomy. She Has a 36-h History of Abdominal Pain and Nausea, and Has an IV Line In Situ
Describe your induction technique, including airway management.
This child is at risk of aspiration and will need a modified rapid sequence induction and endotracheal intubation. The formula for cuffed ETT size suggests 3.5 + 9/4 = 5.75 mmID ETT. I would choose to use a 5.5 mmID ETT, since rounding up to a size 6 mm ETT may result in the cuff catching at the cricoid ring.
Induction technique: Ensure preparation of equipment and drugs and confirm there is a skilled assistant who is familiar with the application of cricoid pressure in children. If there is concern the child is dehydrated or hypovolemic, a 10 mL/kg bolus of Hartmanns would be given before induction.
I would use a modified rapid sequence induction with preoxygenation, fentanyl 0.5–1 μg/kg and propofol 4–5 mg/kg, followed by rocuronium 0.6 mg/kg, application of cricoid pressure and gentle mask ventilation with a high concentration of sevoflurane (4–6%) while monitoring blood pressure. After 2–3 min, or guided by a nerve stimulator assessing paralysis, intubation would be performed with the cuff of the ETT passed just beyond the vocal cords. After checking for ETCO2 and bilateral air entry, the assistant can release cricoid pressure.
During intubation, there is a good view of the vocal cords, but a 5.5 mmID and then a 5.0 cuffed ETT will not pass beyond the vocal cords. What will you do?
The first step would be to ensure the vocal cords are relaxed either clinically or by using a nerve stimulator to confirm muscle relaxation peripherally. Next I would choose a 5.0 UNcuffed ETT. A 4.5 mm cuffed ETT could be used instead, but the internal diameter is small and resistance high in a child of this age. All intubation attempts would be performed gently to avoid airway trauma. Dexamethasone 8–12 mg would be given to reduce the likelihood of airway edema and stridor after extubation, and an ENT review arranged postop. If an ETT even smaller then 5 uncuffed or 4.5 cuffed were needed for intubation, then edema causing critical airway narrowing and obstruction would become a concern, and keeping the child intubated postop until an urgent ENT review would probably be best.
Intubation was achieved with a 5.0 mmID uncuffed ETT and surgery was uneventful. A mildly inflamed, non-perforated appendix was removed. How will you ensure the child is comfortable postop?
A multimodal approach to analgesia would be appropriate, with intraoperative analgesia including morphine 4–5 mg (0.1–0.2 mg/kg), IV paracetamol 390 mg (15 mg/kg), parecoxib 15 mg (0.6 mg/kg) and local anesthetic infiltration to the laparoscope port sites with 8.5 mL of ropivacaine 0.75% (2.5 mg/kg maximum dose). Ondansetron 4 mg would reduce postoperative nausea and vomiting. The child is likely to tolerate oral fluids soon after surgery, and oral analgesia could be used. Oral paracetamol and ibuprofen could be given regularly, and oral oxycodone 2–4 mg 6 hourly as required. Isotonic IV fluids would be continued until the child is drinking adequate amounts.
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