Clinical and Health Affairs
Postoperative Nausea and Vomiting in Pediatric Patients
Postoperative nausea and vomiting (PONV) is a common problem following surgery. In addition to making the patient feel uncomfortable, it can lead to dehydration, electrolyte imbalance, and longer hospital stays. Despite new guidelines, treatment strategies, and better anesthetics, the incidence of PONV in children and adults has remained constant (20% to 35%) over the past 30 years.1-3
Postoperative nausea and vomiting encompasses three main symptoms that may occur separately or in combination: nausea, vomiting or emesis, and retching. One of the goals of anesthesia care is to minimize the likelihood that patients will experience these symptoms. To achieve that, efforts are being made to minimize the use of opioids by adopting regional analgesic techniques and nonopioid medications for perioperative pain control, use a total intravenous anesthesia plan for those with a history of severe PONV, and adopt a prophylactic strategy for PONV prevention.3,4
In addition, antiemetics are also being widely used. Because no single drug effectively blocks all the neural inputs that may trigger nausea and vomiting, practitioners commonly prescribe two or more in combination, for example, a serotinin antagonist (ondansetron) with an inhibitor of prostaglandin synthesis (dexamethasone).
Although our understanding of PONV risk factors has improved dramatically since the early 1990s, we still have much to learn about the pathophysiology of PONV. We have even more to learn about PONV in children. Thus, it has been a focus of recent research at the University of Minnesota. The following brief articles present the findings from two studies, one of children up to 2 years of age who underwent strabismus surgery and the other of children ages 1 month to 16 years who underwent urologic procedures.
These studies looked at the incidence of PONV in both groups during the first 24 hours following surgery. The strabismus study also looked at the incidence of discomfort and emergence agitation/delirium in infants and young children.
Kumar Belani, M.B.B.S., M.S.M
Professor, Department of Anesthesiology
University of Minnesota
References
1. White PF. Prevention of postoperative nausea and vomiting—-a multimodal solution to a persistent problem. N Engl J Med. 2004;350(24):2511-2.
2. Gan TJ, Meyer TA, Apfel CC, et al. Society for Ambulatory Anesthesia guidelines for the management of postoperative nausea and vomiting. Anesth Analg. 2007;105(6):1615-28.
3. Collins CE, Everett LL. Challenges in pediatric ambulatory anesthesia: kids are different. Anesthesiol Clin. 2010:28:315-28.
4. Habib AS, White WD, Eubanks S, Pappas TN, Gan TJ: A randomized comparison of a multimodal management strategy versus combination antiemetics for the prevention of postoperative nausea and vomiting. Anesth Analg. 2004;99(1):77-81.
Discomfort, Delirium, and PONV in Infants and Young Children Undergoing Strabismus Surgery
By Anne M. Stowman, Erick D. Bothun, M.D., and Kumar G. Belani, M.B.B.S., M.S.
■ This article presents the results of a retrospective analysis of anesthesia care and perioperative outcomes in children up to 2 years of age who underwent strabismus surgery during a five-year period at the University of Minnesota Amplatz Children’s Hospital. We reviewed the charts of 74 children to determine perioperative outcomes—namely discomfort, emergence agitation/delirium, and postoperative nausea and vomiting (PONV). We found that although PONV was not an issue in this age group, as it was with older children, discomfort and emergence agitation/delirium do need to be considered during their care.
Previous studies have reported that up to 80% of children who are treated surgically for strabismus suffer from postoperative nausea and vomiting (PONV),1 a serious complication that can lead to discomfort, dehydration, electrolyte imbalance, and delayed hospital discharge. Although efforts have focused on reducing the incidence of PONV in children ages 3 through 8 years, there are no published reports detailing perioperative outcomes in younger children undergoing ambulatory strabismus surgery. The purpose of our study was to summarize perioperative outcomes—namely discomfort, emergence agitation/delirium, and PONV following strabismus surgery in children up to 2 years of age.
Methods
Our study was conducted after it was approved by the Institutional Review Board at the University of Minnesota and found to meet all applicable Health Information Portability and Accountability Act requirements. We conducted a cohort chart review of all patients up to 2 years of age who underwent outpatient strabismus surgery at the University of Minnesota Amplatz Children’s Hospital between August 1, 2004, and July 29, 2009.
Detailed patient information was extracted from the medical record including the anesthesia record, post-anesthesia care unit (PACU) report, phase II recovery room report, and 24-hour post-discharge information obtained by telephone. The extracted information included the patient’s age, gender, weight, past medical history, and American Society of Anesthesiologists physical status; laterality of the surgery; duration of surgery and anesthesia; time in the operating room, PACU, and phase II recovery room; presence of a parent during induction; medications and dosages administered including induction agents, antiemetics, neuromuscular blockers and reversal drugs, and anti-anxiety medications; method of induction; presence of pain, PONV, and emergence agitation/delirium; blood pressure and heart rate; other significant side effects; medications given; and hospital admission following surgery. Because the patients in this study were too young to report symptoms, discomfort was recorded as crying and irritation that responded to analgesic administration. Emergence agitation/delirium was recorded from nursing notes in the PACU and phase II recovery charts. Emergence agitation/delirium was graded according to noted observations and translated to the Pediatric Anesthesia Emergence Delirium (PAED) scale, which takes into consideration the extent to which 1) the child makes eye contact with the caregiver, 2) the child’s actions are purposeful, 3) the child is aware of his or her surroundings, 4) the child is restless, and 5) the child is inconsolable.2
Statistical analysis was performed using tables of descriptive frequencies with basic measures of mean, minimum, maximum, count, and standard deviation. The Student’s T-test was used for evaluation of statistical significance (P <0.05).
Results
We analyzed the records of 74 infants younger than 2 years of age who underwent strabismus procedures. Sixty percent were female and 40% were male, with a mean age of 14.8±5.0 months (range: 5 to 23 months). All patients came to the hospital on the day of surgery with their caregivers understanding that they would be discharged that same day. The anesthesiology care team evaluated all of the patients before surgery in order to develop an anesthesia care plan. All patients followed the ASA’s NPO guidelines prior to surgery. Twenty-nine (39.2%) received midazolam for anxiety orally; another 9.5% received it intravenously intraoperatively, and 9.5% received it postoperatively in the PACU to treat emergence agitation/delerium. Only three were given the antinausea drug ondansetron prior to surgery.
Anesthesia was induced with sevoflurane in all but one child. That child received nontriggering agents (total intravenous anesthesia with propofol, fentanyl and rocuronium) because of a family history of malignant hyperthermia. Desflurane was used as the maintainence agent in 53% of the children; sevoflurane was used in 35%; and isoflurane in 12%. Fifty-one patients received glycopyrrolate, and 12 received atropine at the onset of the procedure. The majority of children were intubated. Cuffed endotracheal tubes were used in 62 children (age 14.3±5.1 months); 10 (age 16.7±7.3 months) had uncuffed endotracheal tubes (P >0.05). A laryngeal mask airway (LMA) device was used in two babies. Nondepolarizing muscle relaxants were used in 47 (64%) children (rocuronium in 25; cisatracurium in 17; vecuronium in five). Of those, only 36 were reversed with neostigmine and glycopyrrolate. The ophthalmologists provided topical analgesia with tetracaine 0.5% to 30 children; six received topical lidocaine, and one received tropicamide 0.17% plus cyclopentolate.
Prior to awakening and extubation, 68 (92%) received prophylaxis for PONV. Fifty-eight of those patients received ondansetron; of those, 37 also received dexamethasone and one received dexamethasone and droperidol. Eight patients received only dexamethasone and two received only droperidol.
Intraoperatively, the anesthesia care team used fentanyl in the majority of patients (95%) for pain. Morphine and alfentanil were also used. Forty-nine percent of the patients received rectal acetaminophen postinduction. Despite receiving opioids intraoperatively, two-thirds of the children (67.1%) required additional analgesics (fentanyl 27%, morphine 23%, and acetaminophen 17%).
During emergence from anesthesia, 36 of the 47 patients given nondepolarizers were reversed in the OR and, with the exception of two patients, were extubated in the OR. Those two were extubated in the PACU.
Pain and discomfort and emergence agitation/delerium were noted in the PACU. Discomfort was noted in 53 children (Table). None had emergence agitation/delirium. There were no episodes of vomiting.
Discussion
We found a much lower incidence of PONV in our group than earlier studies of older children. This may have been due in part to the age of our patients and because of the use of prophylactic antiemetics.
In addition to PONV, our study examined both emergence agitation/delirium and discomfort following strabismus repair. In all instances, nursing notes differentiated between crying and discomfort, restlessness, inconsolability, and agitation. We interpreted crying and irritability without agitation as discomfort. In most cases, over-the-counter medications alleviated the patients’ discomfort. We determined a child was agitated when restlessness and inconsolability (part of the emergence delirium determination criteria) were indicated in the nursing notes.
None of the infants and young children experienced PONV. Although we cannot be sure that none of the patients experienced nausea because of their inability to communicate such a sensation, no obvious signs or symptoms of nausea such as retching, gagging, or vomiting were documented by the nursing staff in the perioperative care units or reported by caregivers at home during the telephone follow-up. We believe the low incidence of PONV may have been the result of administration of antiemetics. Nearly all of the patients (92%) received prophylaxis for postoperative nausea and vomiting. Use of antiemetics prophylactically should be considered in future studies.
Emergence delirium was determined by the PAED scale. Although a number of patients displayed restlessness (n=12) and inconsolability (n=9), all had purposeful movement, seemed aware of their surroundings, and were able to identify their caregiver through eye contact.
Discomfort and agitation were most prevalent postoperatively. Agitation was experienced by 44.6% of patients, but it was never a reason for hospital admission, nor did it ever extend beyond the time in the PACU. Although all patients were administered analgesics intraoperatively (n=74), nearly half (n=33) experienced agitation postoperatively despite administration of opioids and/or acetaminophen intraoperatively. The absence of hypothermia, as indicated by intraoperative and postoperative arrival and departure temperature averages, discounts the idea that lowered body temperature was the reason for agitation. The idea that it may be associated with the use of a particular anesthetic agent is also less relevant, as 81% of our patients received sevoflurane. We were unable to determine whether there was a correlation between IV induction versus mask induction and agitation, as only one of our patients underwent an IV induction. The reason for high rates of agitation needs to be further investigated.
Discomfort was perhaps the biggest concern for patients. Seventy-two percent cried on and off, were fussy, and were easily consoled by being held or rocked or having a parent present. These patients were given analgesics postoperatively and had a predictable response.
One of the limitations of our study was lack of thorough documentation in the patients’ charts. Because our review was done retrospectively, details regarding the care a patient received and a patient’s behavior had to be extracted from the notes taken by staff. In future studies, it would be prudent to have staff watch for certain symptoms and behaviors and consistently document them as well as the status of the patient throughout the operative and postoperative phases.
Conclusion
This study of infants and young children demonstrates that PONV was not common following strabismus surgery and that the incidence may have been reduced through the prophylactic use of antiemetics along with insoluble newer anesthetic agents. We found that discomfort and emergence agitation/delerium during the postoperative period are of greater concern. Anne Stowman is in the department of anesthesiology, Erick Bothun is in the departments of ophthalmology and pediatrics, and Kumar Belani is a professor in the department of anesthesiology at the University of Minnesota.
References
1. Madan R, Bhatia A, Chakithandy S, et al. Prophylactic dexamethasone for postoperative nausea and vomiting in pediatric strabismus surgery: a dose ranging and safety evaluation study. Anesth Analg 2005;100(6):1622-6.
2. Sikich N, Lerman J. Development and psychometric evaluation of the pediatric anesthesia emergence delirium scale. Anesthesiology 2004;100(5): 1138-45.
Postoperative Nausea and Vomiting in Infants and Young Children following Urologic Surgery
By Preeta George, M.B.B.S., M.D., Kumar G. Belani, M.B.B.S., M.S., and Aseem Shukla, M.D.
■ This article presents a cohort review of anesthesia-related perioperative outcomes of children undergoing ambulatory urologic surgery using a combination of general and regional anesthesia. We analyzed the charts of 123 patients who underwent hypospadias repair and circumcision between July 1, 2006, and January 2, 2009, for cases of postoperative nausea and vomiting. We found the incidence to be quite low. We believe the low incidence may have been related to the prophylactic use of antiemetics along with an opioid-sparing technique for anesthesia care.
Postoperative nausea and vomiting (PONV) is a distressing postsurgical problem in children. Despite new guidelines, treatment strategies, and better anesthetics, the incidence of PONV has remained constant (20% to 35%) over the past three decades.1,2 We studied the incidence of PONV in a segment of patients undergoing ambulatory urologic surgery who received a combination of general and regional anesthesia. The goal of this study was to identify cases in which PONV occurred within the first 24 hours after surgery. The presence of PONV was defined as at least one episode of nausea (any degree, including mild) or vomiting or retching, or any combination of these symptoms.3
Methods
Following approval by our Institution Review Board, we analyzed data from a group of pediatric patients who underwent ambulatory circumcision or hypospadias repair at the University of Minnesota Amplatz Children’s Hospital between July 1, 2006, and January 2, 2009. Patients received a combination of general and regional anesthesia.
Included were all infants and children between the ages of 1 month and 16 years who underwent hypospadias repair or circumcision. All surgeries were performed by the same surgeon. Excluded from the study were those patients who were not ambulatory patients. Anesthesia and post-anesthesia care records were reviewed in detail to record the anesthesia plan and the use of antiemetics. All patients had a complete clinical evaluation at least 30 days prior to surgery and were assessed on the day of surgery by an anesthesiologist. The 24-hour postoperative phone call notes by our ambulatory nurse specialist were reviewed for instances of nausea and vomiting.
Results
A total of 72 children (ages 40±46 months) underwent circumcision and another 51 (26±43 months) had hypospadias repair. All followed the American Society of Anesthesiologists’ NPO guidelines; the majority received a general anesthetic that consisted of mask induction with sevoflurane. Nine patients had intravenous induction with propofol. Desflurane or sevoflurane were used for maintenance. Nitrous oxide was used in 16 patients in the circumcision group and seven in the hypospadias group for induction only. In the circumcised group, 26 children had a laryngeal mask airway (LMA) device, 32 were intubated, and 14 were managed with a facemask. All but two of the children who were circumcised received a penile block. One did not receive a caudal; the other had no regional block. Opioids were used sparingly. Sixty-five children received intraoperative fentanyl (2.27±1.28 mcg/kg). In the hypospadias group, five children had an LMA, three received mask ventilation, and 43 were intubated. Twenty-eight received a caudal and 23 were given a penile block. Forty-three received fentanyl (2.88±3.13 mcg/kg).
Seventy-five percent of the children in each group were given the antiemetic ondansetron intraoperatively. Thirty-three percent of the children in the circumcision group and 51% in the hypospadias group also received dexamethasone. Postoperative nausea in the recovery room and before discharge was noted in four of 72 (5.6%) circumcised children and five of 51 (9.8%) children who underwent hypospadias repair (Table). No episodes of vomiting were reported. All children were discharged home. During the first 24 hours after surgery, one child in the hypospadias group had both nausea and vomiting. None returned to the hospital for PONV. Postoperative pain was mainly controlled with acetaminophen. Narcotics were given only if the pain was severe. Postoperatively, five circumcised children received fentanyl, five received morphine, and two received both. Ten of the children who underwent hypospadias repair received fentanyl, six received morphine, and one received both. Upon discharge, all were given a prescription for acetaminophen/hydrocodone (500/7.5 mg per 15 mL) elixir or acetaminophen alone to be used as needed every four to six hours.
Discussion
The cohort review in this subset of pediatric patients was carried out because the incidence of PONV had not been exclusively studied in such children. We found the incidence of PONV to be lower than had been previously reported in infants and children.2 Several factors may be responsible for this. For one thing, the use of opioids was minimized for the majority of patients because simple regional techniques were used instead. Pain and opioids work through different pathways to potentiate PONV. Hence, incorporating a regional anesthetic would circumvent both factors. In addition, approximately 75% of patients received the antiemetic ondansetron, and a good number received dexamethasone intraoperatively, both of which may have contributed to the low incidence of PONV. The majority of infants and young children received the antiemetic during the first half of surgery. Even though nitrous oxide was used in 23 infants, it was used only for induction; this may be the reason only two of those patients experienced PONV. We did not find any association between the use of reversal and PONV.
Following surgery, patients and their families had access to a 24-hour telephone follow-up service. During the 24 hours following discharge, only one patient had an episode of nausea and vomiting. He was not treated with any medication and was managed conservatively. We also did not find a relationship between the time of antiemetic administration and the incidence of PONV. Patients who received antiemetics during the first half of the surgery had a similar incidence of PONV as those who received them during the latter half of the surgery.
Conclusion
We found the incidence of PONV following ambulatory urologic surgery in infants and young children to be quite low. The low incidence was most likely related to the prophylactic use of antiemetics along with limited use of opioids during anesthesia care as well as use of a caudal or penile block for perioperative pain control. MM
Preeta George and Kumar Belani are in the department of anesthesia, and Aseem Shukla is in the department of urology at the University of Minnesota.
References
1. Kovac AL. Management of postoperative nausea and vomiting in children. Paediatr Drugs. 2007;9(1):47-69.
2. Drake R, Anderson BJ, Persson MA, THompson JM. Impact of an antiemetic protocol on postoperative nausea and vomiting in children. Paediatr Anaesth. 2001;11(1):85-91.
3. Apfel CC, Roewer N, Korttila K. How to study postoperative nausea and vomiting. Acta Anaesthesiol Scand. 2002;46(1):921-928.