Supplemental Perioperative Intravenous Crystalloids for Postoperative Nausea and Vomiting in Children Undergoing Oncological Surgery

Overview

Postoperative nausea and vomiting (PONV) is a common complication in the paediatric population and is a source of significant morbidity. The incidence of PONV in children is alarmingly high, as it is estimated to be between 33.2% to 82% depending on patient risk factors. Even with the administration of prophylactic antiemetic medications, the risk of PONV can still be approximately 30%. Various independent risk factors have been implicated in the development of paediatric PONV. The following risk factors were identified: a duration of surgery 30 minutes or longer, age 3 years or older, strabismus, adenoidectomy, and tonsillectomy surgeries, a history of PONV in the child or immediate relatives (parents or siblings), use of volatile anaesthetic, use of opioids, increased postoperative pain, prolonged preoperative fast, and state of dehydration Significant improvement in patient satisfaction can be achieved if the incidence of PONV is decreased. Although not usually life-threatening, PONV may lead to complications commonly associated with vomiting, including dehydration, electrolyte imbalance, and aspiration of gastric contents. In some surgical cases, PONV has also led to wound complications, oesophageal rupture, subcutaneous emphysema, pneumomediastinum, and bilateral pneumothorax. PONV typically describes nausea, vomiting, or retching that can occur starting in the post-anaesthesia care unit (PACU) and continuing through the 24 hours following surgery. PONV occurs twice as often in children than in adults and can lead to longer PACU stays, delays in hospital discharge and subsequent unplanned readmissions, which ultimately lead to significant financial burden on the patients. A variety of antiemetic regimens are recommended for the prevention and treatment of PONV in children, including pharmacotherapy with dexamethasone, 5HT-3 receptor antagonists, butyrophenones, prokinetics, anticholinergics and antihistamines. Hydration is yet another important factor in the development of PONV in paediatric patients. Administration of intravenous dextrose-containing solutions may also prevent PONV. Investigation of the effect of perioperative intravenous crystalloid administration on PONV was initially motivated by the results of observational studies suggesting that perioperative volume status influenced postoperative complication rates. This work showed that PONV was among the most prevalent events after surgery and motivated subsequent inquiry into the relationship between perioperative volume resuscitation and PONV . Multiple reviews have explained the complex physiology of nausea and vomiting. Briefly, the vomiting centre, located in the lateral reticular formation of the medulla, co-ordinates efferent activity to the respiratory, gastrointestinal, and abdominal musculature to produce vomiting. This centre receives afferent stimuli from a variety of sites: the pharynx, gastrointestinal tract chemo- and stretch receptors, the brain (including vestibular information from cranial nerve VIII), aortic baroreceptors, and the chemoreceptor trigger zone. The chemoreceptor trigger zone is a neural centre physiologically outside of the blood-brain barrier, which provides afferent information to the vomiting centre in response to noxious stimuli in the blood. Patients particularly paediatrics typically present for surgery with a fluid deficit secondary to fasting, bleeding, bowel preparation, and other causes of dehydration. It has been proposed that brainstem, vestibular, and intestinal hypoperfusion, with concomitant ischaemia, may mediate nausea and vomiting. Supplemental intravenous crystalloids could serve to mitigate this effect; however, no proven explanation for the putative role of volume status in this model exists. Hypovolemia has been associated with a rise in postoperative morbidity and mortality ranging from PONV to other complications such as organ dysfunction . Hypovolemia from overnight fasting without adequate fluid replacement can cause adverse effects postoperatively . Intravenous crystalloids are widely administered before, during, and after procedures requiring general anaesthesia. They are inexpensive and have relatively few adverse effects. A prior systematic review has suggested that supplemental intravenous crystalloids may be effective in preventing PONV . However, studies of supplemental perioperative intravenous crystalloids were noted to vary widely on the specific volumes administered. Despite evidence-based, multimodal prophylactic regimens, PONV remains a prevalent clinical problem . The use of pharmacologic agents alone reduces the risk of PONV but increases the risk of side effects. Intravenous crystalloids are an attractive treatment modality. Many different intravenous fluid interventions have been tested in a wide variety of surgical and anaesthetic contexts.