Pyloric stenosis

Spinal anesthesia compared with general anesthesia for neonates with hypertrophic pyloric stenosis. A retrospective study

BACKGROUND

Studies of spinal anesthesia in children are limited to a reduced group of high-risk patients and it remains relatively underused compared with general anesthesia in this age group in most institutions. In our experience, spinal anesthesia appears to be a good alternative to general anesthesia during pyloromyotomy in neonates and infants.

AIMS

The purpose of this study was to retrospectively evaluate respiratory morbidity of spinal anesthesia compared to general anesthesia in infants undergoing pyloromyotomy.

METHODS

The University Hospital of Salamanca used spinal or general anesthesia on infants undergoing pyloromyotomy between 2003 and 2017. The primary outcome assessed was the prevalence of apnea. The second one was the prevalence of oxygen saturation below 95%. An analysis was performed using t test or Mann-Whitney U test for continuous variables, and Chi-square for categorical variables. Logistic regression was done to account for differences in demographic and clinical covariates.

RESULTS

The study sample consisted of 68 infants and neonates undergoing pyloromyotomy (48 with spinal anesthesia and 20 with general anesthesia). There was a significant difference in apneic episodes after surgery between general (number/percentage = 5/20, 25%) and spinal (number/percentage = 0/48, 0%) groups. Absolute risk reduction is 25% (CI 95%: 6%-44%), P < .001.

CONCLUSION

Spinal anesthesia in neonates with hypertrophic pyloric stenosis undergoing pyloromyotomy was a viable alternative to general anesthesia, reducing the respiratory morbidity associated with the latter.

Does metabolic alkalosis influence cerebral oxygenation in infantile hypertrophic pyloric stenosis?

BACKGROUND

This pilot study focuses on regional tissue oxygenation (rSO₂) in patients with infantile hypertrophic pyloric stenosis in a perioperative setting. To investigate the influence of enhanced metabolic alkalosis (MA) on cerebral (c-rSO₂) and renal (r-rSO₂) tissue oxygenation, two-site near-infrared spectroscopy (NIRS) technology was applied.

MATERIALS AND METHODS

Perioperative c-rSO₂, r-rSO₂, capillary blood gases, and electrolytes from 12 infants were retrospectively compared before and after correction of MA at admission (T1), before surgery (T2), and after surgery (T3).

RESULTS

Correction of MA was associated with an alteration of cerebral oxygenation without affecting renal oxygenation. When compared to T1, 5-min mean (± standard deviation) c-rSO₂ increased after correction of MA at T2 (72.74 ± 4.60% versus 77.89 ± 5.84%; P = 0.058), reaching significance at T3 (80.79 ± 5.29%; P = 0.003). Furthermore, relative 30-min c-rSO₂ values at first 3 h of metabolic compensation were significantly lowered compared with postsurgical states at 16 and 24 h. Cerebral oxygenation was positively correlated with levels of sodium (r = 0.37; P = 0.03) and inversely correlated with levels of bicarbonate (r = -0.34; P = 0.05) and base excess (r = -0.36; P = 0.04). Analysis of preoperative and postoperative cerebral and renal hypoxic burden yielded no differences. However, a negative correlation (r = -0.40; P = 0.03) regarding hematocrite and mean r-rSO₂, indirectly indicative of an increased renal blood flow under hemodilution, was obtained.

CONCLUSIONS

NIRS seems suitable for the detection of a transiently impaired cerebral oxygenation under state of pronounced MA in infants with infantile hypertrophic pyloric stenosis. Correction of MA led to normalization of c-rSO₂. NIRS technology constitutes a promising tool for optimizing perioperative management, especially in the context of a possible diminished neurodevelopmental outcome after pyloromyotomy.

The timing and prevalence of intraoperative hypotension in infants undergoing laparoscopic pyloromyotomy at a tertiary pediatric hospital

BACKGROUND

Intraoperative hypotension may be associated with adverse outcomes in children undergoing surgery. Infants and neonates under 6 months of age have less autoregulatory cerebral reserve than older infants, yet little information exists regarding when and how often intraoperative hypotension occurs in infants.

AIMS

To better understand the epidemiology of intraoperative hypotension in infants, we aimed to determine the prevalence of intraoperative hypotension in a generally uniform population of infants undergoing laparoscopic pyloromyotomy.

METHODS

Vital sign data from electronic records of infants who underwent laparoscopic pyloromyotomy with general anesthesia at a children's hospital between January 1, 1998 and October 4, 2013 were analyzed. Baseline blood pressure (BP) values and intraoperative BPs were identified during eight perioperative stages based on anesthesia event timestamps. We determined the occurrence of relative (systolic BP <20% below baseline) and absolute (mean arterial BP <35 mmHg) intraoperative hypotension within each stage.

RESULTS

A total of 735 full-term infants and 82 preterm infants met the study criteria. Relative intraoperative hypotension occurred in 77%, 72%, and 58% of infants in the 1-30, 31-60, and 61-90 days age groups, respectively. Absolute intraoperative hypotension was seen in 21%, 12%, and 4% of infants in the 1-30, 31-60, and 61-90 days age groups, respectively. Intraoperative hypotension occurred primarily during surgical prep and throughout the surgical procedure. Preterm infants had higher rates of absolute intraoperative hypotension than full-term infants.

CONCLUSIONS

Relative intraoperative hypotension was routine and absolute intraoperative hypotension was common in neonates and infants under 91 days of age. Preterm infants and infants under 61 days of age experienced the highest rates of absolute and relative intraoperative hypotension, particularly during surgical prep and throughout surgery.

Acetaminophen for analgesia following pyloromyotomy: does the route of administration make a difference?

Background

During the perioperative care of infants with hypertrophic pyloric stenosis, an opioid-sparing technique is often advocated due to concerns such as postoperative hypoventilation and apnea. Although the rectal administration of acetaminophen is commonly employed, an intravenous (IV) preparation is also currently available, but only limited data are available regarding IV acetaminophen use for infants undergoing pyloromyotomy. The objective of the current study was to compare the efficacy of IV and rectal acetaminophen for postoperative analgesia in infants undergoing laparoscopic pyloromyotomy.

Methods

A retrospective review of the use of IV and rectal acetaminophen in infants undergoing laparoscopic pyloromyotomy was performed. The efficacy was assessed by evaluating the perioperative need for supplemental analgesic agents, postoperative pain scores, tracheal extubation time, time in the postanesthesia care unit, time to oral feeding, and time to hospital discharge.

Results

The study cohort included 68 patients, of whom 34 patients received IV acetaminophen and 34 received rectal acetaminophen. All patients also received local infiltration of the surgical site with 0.25% bupivacaine. No intraoperative opioids were administered. There was no difference between the two groups with regard to postoperative pain scores, need for supplemental analgesic agents, time in the postanesthesia care unit, or time in the hospital. There was no difference in the number of children who tolerated oral feeds on the day of surgery or in postoperative complications.

Conclusion

Our preliminary data suggest that there is no clinical difference or advantage with the use of IV versus rectal acetaminophen in infants undergoing laparoscopic pyloromyotomy.

Perioperative care of infants with pyloric stenosis

Pyloric stenosis (PS) is one of the most common surgical conditions affecting neonates and young infants. The definitive treatment for PS is surgical pyloromyotomy, either open or laparoscopic. However, surgical intervention should never be considered urgent or emergent. More importantly, emergent medical intervention may be required to correct intravascular volume depletion and electrolyte disturbances. Given advancements in surgical and perioperative care, morbidity and mortality from PS should be limited. However, either may occur related to poor preoperative resuscitation, anesthetic management difficulties, or postoperative complications. The following manuscript reviews the current evidence-based medicine regarding the perioperative care of infants with PS with focus on the preoperative assessment and correction of metabolic abnormalities, intraoperative care including airway management (particularly debate related to rapid sequence intubation), maintenance anesthetic techniques, and techniques for postoperative pain management. Additionally, reports of applications of regional anesthesia for either postoperative pain control or as an alternative to general anesthesia are discussed. Management recommendations are provided whenever possible.

Gas induction for pyloromyotomy

BACKGROUND

Infants with pyloric stenosis are considered to be at high risk of aspiration on induction of anesthesia. Traditionally, texts have recommended classic rapid sequence induction (RSI) or awake intubation (AI). AI has generally fallen out of favor, while the components of RSI have become increasingly controversial. Infants are at high risk of hypoxemia if ventilation is not maintained while waiting for neuromuscular blockade to establish. The efficacy of cricoid pressure (CP) to prevent aspiration has not been proven. It can impair visualization of the glottis and make intubation difficult. It is debatable whether any RSI technique is needed for pyloromyotomy. A recent review of 235 infants reported no aspiration events. These children were anesthetized with a variety of techniques, including RSI, gas induction, and AI. In our institution, we teach a gaseous induction. The nasogastric tube is used to empty the stomach and anesthesia is induced with sevoflurane. A nondepolarizing muscle relaxant is administered and ventilation maintained until neuromuscular blockade is established and intubating conditions are optimal. We report our experience of this technique.

METHOD

A retrospective medical notes review of all patients undergoing pyloromyotomy between 2005 and 2012.

RESULTS

There were 269 patients (84.4% male, mean weight 3.74 kg ± 0.74). Two hundred and fifty-two (93.7%) received gas inductions and 17 (6.3%) intravenous (IV) inductions. Two children received an RSI. No patient-specific factors were identified to explain operator choice in those receiving IV inductions. There were no recorded aspiration events.

CONCLUSION

Gas induction can be considered for children undergoing pyloromyotomy.

The ins and outs of pyloromyotomy: what we have learned in 35 years

PURPOSE/BACKGROUND

The aim of the study is to evaluate a large series of infantile hypertrophic pyloric stenosis (IHPS) patients treated by one pediatric surgeon focusing on their diagnostic difficulties and complications.

METHODS

From July 1969 to December 2003 (inclusive), the charts of 791 infants with IHPS were retrospectively reviewed.

RESULTS

There were 647 (82%) males and 144 (18%) females; mean age was 38 days, median 51 (range 7 days-10 months). When ultrasonography (US) was routinely used (1990), the age at diagnosis decreased to <40 days. The mean weight before and after routine US was 3.2 kg, median 3 (range 1.5-6). Twenty-five (3.1%) were premature at diagnosis, mean age 49 days, median 56, (range 1-3 months) and mean weight 2.5 kg, median 2.3 (range 1.5-3.2). Eighty-one (10%) had a positive family history. Forty-four (5%) were non-Caucasians. Seventy-five (9 %) had other medical conditions, anomalies and/or associated findings. Sixty (7%) patients had abnormal preoperative electrolytes. Ten (1.2%) pylorics occurred after newborn operations. Of the entire total (791) who were treated, there were 13 (1.7%) not operated on. All operations were done open initially through one of two right upper quadrant incisions, and then through an upper midline incision under general endotracheal anesthesia; 14 (1.7 %) had concomitant procedures. Prophylactic antibiotics (from 1982) decreased the wound infection rate to 3.9%. There were a total of 87 (10%) complications which included 9 (1.1%) intraoperative, (including mistaken diagnoses) 78 (9%) postoperative: 59 (2%) early (<1 month) and 19 (2.4%) late (>1 month). The 13 (1.6%) postoperative transfers (12 from non-pediatric surgeons) had 16 (18%) complications (including 1 death); five (33%) requiring reoperation (4 incomplete, 1 perforation). There were two deaths.

CONCLUSIONS

IHPS should be considered in any vomiting infant. US allows earlier diagnosis. Serious complications are uncommon and avoidable, but recognizable and easily corrected. Higher surgeon volume of pyloromyotomies (>14 per year) is associated with fewer complications.

Gastric tubes and airway management in patients at risk of aspiration: history, current concepts, and proposal of an algorithm

Rapid sequence induction and intubation (RSII) and awake tracheal intubation are commonly used anesthetic techniques in patients at risk of pulmonary aspiration of gastric or esophageal contents. Some of these patients may have a gastric tube (GT) placed preoperatively. Currently, there are no guidelines regarding which patient should have a GT placed before anesthetic induction. Furthermore, clinicians are not in agreement as to whether to keep a GT in situ, or to partially or completely withdraw it before anesthetic induction. In this review we provide a historical perspective of the use of GTs during anesthetic induction in patients at risk of pulmonary aspiration. Before the introduction of cricoid pressure (CP) in 1961, various techniques were used including RSII combined with a head-up tilt. Sellick initially recommended the withdrawal of the GT before anesthetic induction. He hypothesized that a GT increases the risk of regurgitation and interferes with the compression of the upper esophagus during CP. He later modified his view and emphasized the safety of CP in the presence of a GT. Despite subsequent studies supporting the effectiveness of CP in occluding the esophagus around a GT, Sellick's early view has been perpetuated by investigators who recommend partial or complete withdrawal of the GT. On the basis of available information, we have formulated an algorithm for airway management in patients at risk of aspiration of gastric or esophageal contents. The approach in an individual patient depends on: the procedure; type and severity of the underlying pathology; state of consciousness; likelihood of difficult airway; whether or not the GT is in place; contraindications to the use of RSII or CP. The algorithm calls for the preanesthetic use of a large-bore GT to remove undigested food particles and awake intubation in patients with achalasia, and emptying the pouch by external pressure and avoidance of a GT in patients with Zenker diverticulum. It also stipulates that in patients with gastric distension without predictable airway difficulties, a clinical and imaging assessment will determine the need for a GT and in severe cases an attempt to insert a GT should be made. In the latter cases, the success of placement will indicate whether to use RSII or awake intubation. The GT should not be withdrawn and should be connected to suction during induction. Airway management and the use of GTs in the surgical correction of certain gastrointestinal anomalies in infants and children are discussed.

Management of hypertrophic pylorus stenosis with ultrasound guided single shot epidural anaesthesia--a retrospective analysis of 20 cases

AIM

To retrospectively describe the performance of ultrasound guided thoracic epidural anaesthesia under sedation for anaesthesia management of open pyloromyotomy.

BACKGROUND

Anaesthesia management for hypertrophic pylorus stenosis (HPS) is usually performed under general anaesthesia with tracheal intubation. Only a few publications describe avoidance of tracheal intubation in infants by using spinal or caudal anaesthesia. The present retrospective analysis describes the performance of ultrasound guided thoracic epidural anaesthesia under sedation for anaesthetic management of open pyloromyotomy.

METHODS

Twenty consecutive infants scheduled for pyloromyotomy according to the Weber-Ramstedt technique were retrospectively analysed. After sedation with nalbuphine and propofol, an ultrasound guided single shot thoracic epidural anaesthesia was performed with 0.75 ml·kg(-1) ropivacaine 0.475%. Insufficient blockade was defined as increase of HR > 15% from initial value and/or any movements at skin incision. In those cases we were prepared for rapid sequence intubation according to the departmental standard.

RESULTS

All pyloromyotomies could be performed under single shot thoracic epidural anaesthesia and sedation. One case of moderate oxygen desaturation was treated with intermittent ventilation via face mask.

CONCLUSIONS

Thoracic epidural anaesthesia under sedation for pyloromyotomy has been a useful technique in this retrospective series of infants suffering from HPS. In 1/20 infants short term assisted ventilation via face mask was required. Undisturbed surgery was possible in all cases.

Impact of spinal anesthesia for open pyloromyotomy on operating room time

PURPOSE

When pyloromyotomy for hypertrophic pyloric stenosis (HPS) is performed under general anesthesia, metabolic abnormalities and fluid deficits coupled with residual anesthetics may increase the risk of postoperative apnea, thereby, prolonging operating room time and delaying extubation. Spinal anesthesia has been found to reduce the rate of postoperative apnea in high-risk infants. The aim of the study was to evaluate the effect of spinal vs general anesthesia on operating room time in infants undergoing open pyloromyotomy.

METHODS

Data for 60 infants who underwent pyloromyotomy under spinal (n = 24) or general (n = 36) anesthesia at a tertiary pediatric medical center were derived from the computerized database. Primary outcome measures were total operating room time, procedure duration, anesthesia release time, wake-up time, and anesthesia control time (anesthesia release plus wake-up). Nonparametric Mann-Whitney test was used for statistical analysis, and Levene's test was used to assess the equality of variances in samples; P <or= .05 was considered significant.

RESULTS

Mean total operating room time was 50.9 (12.1) minutes in the spinal anesthesia group and 69.5 (26.8) minutes in the general anesthesia group (P = .001). Corresponding values for mean wake-up time were 3.6 (2.9) and 17.2 (25.3) minutes (P < .001), and for mean anesthesia control time, 13.2 (6.7) and 28.5 (24.6) minutes (P < .001). There were no between-group differences in procedure duration or anesthesia release time. On Levene's test, between-group differences were significant for total operating time and wake-up time (P = .01 for both).

CONCLUSIONS

The use of spinal anesthesia for open pyloromyotomy in infants with HPS shortens the operating room time by reducing the wake-up time.

Rapid correction of metabolic alkalosis in hypertrophic pyloric stenosis with intravenous cimetidine: preliminary results

PURPOSE

Pyloromyotomy has been the treatment of choice for hypertrophic pyloric stenosis (HPS) for the past century. In most HPS cases, there is mild metabolic alkalosis, which requires intravenous fluid resuscitation with 5% dextrose/normal saline for 1-2 days. However, in some cases, due to a delay in diagnosis, alkalosis becomes severe and a much longer resuscitation period (5-10 days) is required to normalize serum pH. Metabolic alkalosis of HPS results from excessive vomiting of hydrochloric acid; and therefore if its production is reduced, serum pH can be normalized faster. In this study, the use of intravenous cimetidine (CM) in a small number of infants with HPS is presented.

METHODS

Over a 28-month period, 32 HPS cases, including a sub-group of 17 infants (aged 7-9 weeks) with arterial pH >7.60, were admitted to a tertiary referral unit. Four infants in this sub-group were treated with standard resuscitation fluids for 4 days prior to intravenous CM, while 12 infants received CM immediately. Intravenous CM (10 mg/kg) was given at twice daily until arterial pH was less than 7.50. In one case, intravenous omeprazole at 0.1 mg/kg was given instead of CM.

RESULTS

In all 17 cases, CM treatment or omeprazole therapy (for 12-48 h) reduced pH to less than 7.50, thus allowing for Ramstedt pyloromyotomy the same day. These patients were allowed oral feeding on the following day and were discharged at 1-3 post-operative days. No complications due to CM (or omperazole) treatment were observed.

CONCLUSION

Intravenous CM administration can rapidly normalize severe metabolic alkalosis in HPS patients. As a result, pyloromyotomy can be performed sooner reducing both hospital stay and costs.

Premedication for tracheal intubation in neonates: confusion or controversy?

Tracheal intubation is performed frequently in the NICU and delivery room. This procedure is extremely distressing, painful, and has the potential for airway injury. Premedication with sedatives, analgesics, and muscle relaxants is standard practice for pediatric and adult intubation, yet the use of these drugs is not common for intubation in neonates. The risks and benefits of using premedications for intubating unstable newborns are hotly debated, although recent evidence shows that premedication for non-urgent or semi-urgent intubations is safer and more effective than awake intubations. This article reviews clinical practices reported in surveys on premedication for neonatal intubation, the physiological effects of laryngoscopy and intubation on awake neonates, as well as the clinical and physiological effects of different drug combinations used for intubation. A wide variety of drugs, either alone or in combination, have been used as premedication for elective intubation in neonates. Schematically, these studies have been of three main types: (a) studies comparing awake intubation versus those with sedation or analgesia, (b) studies comparing different premedication regimens comprising sedatives, analgesics, and anesthetics, and (c) case series of neonates in which some authors have reported their experience with a specific premedication regimen. The clinical benefits described in these studies and the need for pain control in neonates make the case for using appropriate premedication routinely for elective or semi-urgent intubations. Tracheal intubation without the use of analgesia or sedation should be performed only for urgent resuscitations in the delivery room or other life-threatening situations when intravenous access is unavailable.

An assessment of interrater reliability of the ASA physical status classification in pediatric surgical patients

BACKGROUND

The American Society of Anesthesiologists physical status classification (ASA-PS) is used worldwide by anesthesia providers as an assessment of the preoperative physical status of patients. This assessment score has been inconsistently assigned by anesthesia providers among adult surgical patients. This study tested the reliability of assignment of ASA-PS classification among pediatric anesthesia providers.

METHODS

A postal questionnaire was sent to a randomly selected sample of full members of the Society of Pediatric Anesthesiologists. Participants were asked to assign ASA-PS for 10 clinical case scenarios chosen from regular pediatric surgical cases at the investigators' institution.

RESULTS

The response rate to our mailing was 54%. There was a moderate overall agreement among pediatric anesthesia providers in assigning ASA-PS for pediatric surgical patients (exact agreement 40.5-78.6%; kappa = 0.479). Exact agreement improved for combined ASA classifications of I and II (83%), and III and IV (95%).

CONCLUSION

These findings suggest a moderate agreement among pediatric anesthesia providers in assigning ASA-PS classification to selected pediatric case scenarios. Most disagreement, however, represented a tendency of outside care providers to assign a higher ASA physical status for cases. Furthermore, agreement was excellent for low risk (i.e. ASA I and II) as well as high risk (ASA III and IV) cases.

Prise en charge périopératoire de la sténose du pylore en France en 1999 : résultats d’une enquête postale

OBJECTIVE

The aim of this postal survey was to know how were treated infants with hypertrophic pyloric stenosis in France in 1999.

METHODS

A questionnaire was sent to all French members of the Association Des Anesthésistes Réanimateurs Pédiatriques d'Expression Française (Adarpef).

RESULTS

Half the cases of pyloric stenosis treated in France in 1999 were related by the survey. Preoperative management was short lasting (24 h) while the advised guidelines regarding biologic criteria for operation were poorly followed. Nevertheless, crush induction was only performed in 80%.

CONCLUSION

The management of infants with pyloric stenosis must be improved, at least to obtain the generalization of crush induction.

Hyperkalemia and pyloric stenosis

Children presenting with pyloric stenosis have hypochloremic metabolic alkalosis and their serum potassium levels are thought to be low or normal. We reviewed potassium levels in infants with pyloric stenosis. Thirty-six percent of patients with pyloric stenosis had increased serum potassium levels. We conclude that hyperkalemia may be more common in children with pyloric stenosis than previously thought.

IMPLICATIONS

A significant number of infants with pyloric stenosis have a serum potassium value above the normal limit.

The effectiveness and safety of spinal anaesthesia in the pyloromyotomy procedure

BACKGROUND

Hypertrophic pyloric stenosis is a relatively common disorder of the gastrointestinal tract in infancy, causing projectile vomiting and metabolic abnormalities. Surgical management in the form of pyloromyotomy under general anaesthesia has been reported as safe for relieving the obstructed bowel. A number of studies have demonstrated the advantages of spinal anaesthesia over general anaesthesia in high risk infants undergoing minor infraumbilical surgery. The purpose of this study was to evaluate spinal anaesthesia as an alternative option to general anaesthesia in infants undergoing pyloromyotomy.

METHODS

Twenty-five infants undergoing pyloromyotomy under spinal anaesthesia were studied. Haemodynamic and respiratory parameters were noted before performing the spinal block, 5 min after the spinal block, and every 10 min after performing the spinal block; for a total period of 30 min. The spinal block was performed using spinal isobaric bupivacaine 0.5%, 0.8 mg.kg-1. Blood pressure, heart rate, respiratory rate and oxygen saturation values were recorded.

RESULTS

The sensory levels achieved ranged between T3-T5 thoracic segments within 6-8 min and were sufficient to perform surgery in 23 cases. There were no statistically significant differences in the oxygen saturation, systolic blood pressure and respiratory rate compared with before the spinal block and after 5, 10, 20 and 30 min.

CONCLUSIONS

This study proposes that spinal anaesthesia is an alternative option to general anaesthesia in infants undergoing pyloromyotomy, and should be considered in infants undergoing pyloromyotomy.

Caudal block with 4 mg x kg-1 (1.6 ml x kg-1) of bupivacaine 0.25% in children undergoing surgical correction of congenital pyloric stenosis

BACKGROUND

Since 1970, bupivacaine 0.25% in a dose of 4 mg x kg-1 (1.6 ml x kg-1) has been used at the Hospital Infantil de México for caudal block in children undergoing surgical correction of congenital pyloric stenosis (CPS). Although this dose is considered unsafe, in our experience, it has been associated with a high success rate and a low incidence of adverse events. This experience has not been previously documented.

METHODS

A retrospective cohort of patients undergoing surgical correction of CPS was studied. Nineteen patients received general anaesthesia while 223 received caudal block. The latter were then grouped according to the sedation technique. The rate of successful caudal blocks and complications were considered the major outcomes of the study, whereas the postsurgical fasting period and hospital stay were considered secondary outcomes.

RESULTS

The rate of success of caudal block was 96%. Anaesthetic complications related to bupivacaine were present in 1.3%. Mortality occurred in the postoperatory period in one septic patient who also was suffering from gastroschisis that required general anaesthesia. Postoperatory fasting period and hospital stay tended to be higher with general anaesthesia than caudal block. However, of the 19 patients receiving general anaesthesia, five suffered serious comorbidity and nine were failed caudal blocks.

CONCLUSIONS

Caudal block with bupivacaine 0.25% (4 mg x kg-1) was associated with a low rate of anaesthetic complications. Further prospective studies to clarify the risks and benefits are required.

A randomized multicenter study of remifentanil compared with halothane in neonates and infants undergoing pyloromyotomy. I. Emergence and recovery profiles

Pyloric stenosis is sometimes associated with hemodynamic instability and postoperative apnea. In this multicenter study we examined the hemodynamic response and recovery profile of remifentanil and compared it with that of halothane in infants undergoing pyloromyotomy. After atropine, propofol, and succinylcholine administration and tracheal intubation, patients were randomized (2:1 ratio) to receive either remifentanil with nitrous oxide and oxygen or halothane with nitrous oxide and oxygen as the maintenance anesthetic. Pre- and postoperative pneumograms were done and evaluated by an observer blinded to the study. Intraoperative hemodynamic data and postanesthesia care unit (PACU) discharge times, PACU recovery scores, pain medications, and adverse events (vomiting, bradycardia, dysrhythmia, and hypoxemia) were recorded by the study's research nurse. There were no significant differences in patient age or weight between the two groups. There were no significant differences in hemodynamic values between the two groups at the various intraoperative stress points. The extubation times, PACU discharge times, pain medications, and adverse events were similar for both groups. No patient anesthetized with remifentanil who had a normal preoperative pneumogram had an abnormal postoperative pneumogram, whereas three patients with a normal preoperative pneumogram who were anesthetized with halothane had abnormal pneumograms after.

IMPLICATIONS

The use of ultra-short-acting opioids may be an appropriate technique for infants less than 2 mo old when tracheal extubation after surgery is anticipated.

An audit of postoperative analgesia after pyloromyotomy

Seventy-two cases of pyloric stenosis treated in our institution in the last five years were reviewed in an attempt to determine the need for postoperative analgesia after pyloromyotomy in infants. All children had their wound infiltrated with a mean dose of 2.16+/-1.43 mg x kg(-1) of bupivacaine, and first analgesia was required 9.12+/-8.04 h after surgery. Paracetamol was the main analgesic administered (average of two doses of approximately 20 mg x kg(-1)). Only three patients required postoperative opioids. In conclusion, there was a low consumption of analgesics after pyloromyotomy. Furthermore, infiltration of the wound appeared to be beneficial since time to administration of first postoperative analgesia was delayed.

Diagnostic aids in the differentiation of pyloric stenosis from severe gastroesophageal reflux during early infancy: the utility of serum bicarbonate and serum chloride

This study evaluated whether serum bicarbonate levels, serum chloride levels, and other diagnostic criteria could be used to differentiate pyloric stenosis (PS) from severe gastroesophageal reflux (GER) during early infancy. The investigation was a retrospective, case-control study conducted in the emergency department of a large, academic children's hospital. Cases were 75 consecutive infants with PS confirmed in the operating room. Controls were 75 consecutive infants 12 weeks of age or younger with the diagnosis of GER whose serum electrolytes had been examined. Projectile vomiting was sensitive (0.93) but not specific (0.39) for PS. The mean serum bicarbonate level was 27.2 mmol/L for PS patients and 22.3 mmol/L for GER patients (P < .00001), and the mean serum chloride level was 95.7 mmol/L and 103.6 mmol/L for PS patients and GER patients, respectively (P < .00001). Serum bicarbonate levels of > or =29 mmol/L and serum chloride levels of < or =98 mmol/L had high positive predictive values (0.96 and 0.97, respectively) and were specific (0.99 for both) but not very sensitive (0.36 and 0.50, respectively) in identifying patients with PS. Only one patient would have been misclassified (false positive) as having PS using either of these cutoff values. These laboratory tests can also help discriminate between PS and GER when the history and physical examination fail to do so. For example, of the 20 patients with PS who did not have a pyloric mass palpated, 3 (15%) had serum bicarbonate levels of > or =29 mmol/L, and 6 (30%) had serum chloride levels of < or =98 mmol/L. In conclusion, the serum bicarbonate or serum chloride level offers a useful additional diagnostic tool in the evaluation of children presenting during early infancy with vomiting of uncertain etiology.

A comparison of awake versus paralyzed tracheal intubation for infants with pyloric stenosis

This prospective, nonrandomized, observational study of 76 infants with pyloric stenosis was conducted at an academic children's hospital and compared awake versus paralyzed tracheal intubation in terms of successful first attempt rate, intubation time, heart rate (HR) and arterial hemoglobin oxygen saturation (SpO2) changes, and complications. Three groups were determined by intubation method: awake (A) with an oxygen-insufflating laryngoscope, after rapid-sequence induction (R), or after modified rapid-sequence induction (M) including ventilation through cricoid pressure. Successful first attempt intubation rate was 64% for Group A versus 87% for paralyzed Groups R and M (P = 0.028). Median intubation time was 63 s in Group A versus 34 s in Groups R and M (P = 0.004). Transient, mild decreases in mean HR and SpO2 and incidences of significant bradycardia and decreased SpO2 did not vary by group. Complications, including bronchial or esophageal intubation, emesis, and oropharyngeal trauma, were few. Senior anesthesiologists intervened in four tracheal intubations. We advocate anesthetized, paralyzed tracheal intubation because struggling with conscious infants takes longer, often requires multiple attempts, and prevents neither bradycardia nor decreased SpO2. After induction, additional mask ventilation with O2 confers no advantage over immediate tracheal intubation in preserving SpO2.

IMPLICATIONS

In our children's hospital, awake tracheal intubation was not superior to anesthetized, paralyzed intubation in maintaining adequate oxygenation and heart rate or in reducing complications, and should be abandoned in favor of the latter technique for routine anesthetic management of otherwise healthy infants with pyloric stenosis.

Gastric fluid volume in infants for pyloromyotomy

PURPOSE

To quantify gastric fluid volumes in infants with pyloric stenosis presenting for pyloromyotomy and to demonstrate endoscopically the efficacy of blind aspiration for gastric fluid recovery. We hypothesized that previous diagnostic contrast studies, preoperative nasogastric suction, and fasting interval would not affect these volumes.

METHODS

Seventy-five infants scheduled for pyloromyotomy were given atropine before induction of anaesthesia. For those who had undergone preoperative nasogastric suction, the nasogastric tube was aspirated and removed. A 14 F multiorificed orogastric catheter was blindly passed to aspirate gastric fluid for measurement. Following tracheal intubation, 15/75 subjects underwent gastroscopy to measure residual gastric fluid.

RESULTS

Gastric fluid volume removed by blind aspiration averaged 4.8 +/- 4.3 ml.kg-1 with 83% of patients having > 1.25 ml.kg-1. Although 14 of the 15 patients evaluated by endoscope had < or = 1 ml residual gastric fluid, one had 1.8 ml.kg-1. Recovery of total gastric fluid volume by blind aspiration averaged 96 +/- 7%. The large gastric fluid volumes were independent of a history of barium study, preoperative nasogastric suction, and fasting interval.

CONCLUSION

Infants with pyloric stenosis have large gastric fluid volumes which are not substantially reduced by preoperative nasogastric suction. Blind aspiration of gastric contents prior to induction of anaesthesia provides a reliable estimate of total gastric fluid for most of these infants, although the occasional infant may retain a small amount of gastric fluid. The clinical importance of such a residual volume is uncertain.

Transient neonatal myasthenia gravis and pyloric stenosis

The case report describes the occurrence of hypertrophic pyloric stenosis in a premature infant with neonatal myasthenia gravis. The infant presented for pyloromyotomy on the nineteenth day of life. Diagnosis of myasthenia gravis was made based on maternal history and clinical findings of poor muscle tone, weak suck, and weak cry. The anesthetic management is discussed with reference to the problems of newborn myasthenia gravis and pyloric stenosis as they relate to anesthetic drugs and techniques.

Awake intubation increases intracranial pressure without affecting cerebral blood flow velocity in infants

Tracheal intubation is frequently required in neonatal anaesthetic practice. Awake intubation is one method of securing the airway and in certain circumstances, for many anaesthetists, can be preferable to intubation following induction of anaesthesia. Previous studies have inferred that the elevation in anterior fontanelle pressure observed during tracheal intubation in neonates was caused by an increase in cerebral blood flow although it was never measured. In this study, direct methods were used to observe changes in the cerebral circulation. Thirteen neonates, ASA I to III (E), aged from 1 to 34 days of age were studied. Patients were randomized to receive either tracheal intubation awake or following induction of anaesthesia with thiopentone 5 mg.kg-1 and succinylcholine 2 mg.kg-1. Heart rate, systolic arterial blood pressure, anterior fontanelle pressure, cerebral blood flow velocity (using transcranial Doppler sonography) and oxygen saturation were recorded at the following intervals: baseline (not crying), after intravenous atropine 0.02 mg.kg-1, during laryngoscopy, immediately after insertion of the endotracheal tube, one and five minutes later. The use of atropine masked the cardiovascular responses to intubation. Whereas the change in anterior fontanelle pressure from baseline was different between the groups (P < 0.05), the cerebral blood flow velocity variables were not. The rise in anterior fontanelle pressure seen in the awake group may be attributed to a reduction of the venous outflow from the cranium thereby increasing cerebral blood volume and subsequently the intracranial pressure.

[Anesthesia in the management of pyloric stenosis. Evaluation of the combination of propofol-halogenated anesthetics]

This study was aimed at evaluating haemodynamic changes during an anaesthetic sequence for full stomach, using propofol as induction agent and volatile anaesthetics for maintenance of anaesthesia in infants scheduled for surgical cure of hypertrophic pyloric stenosis. After correction of preoperative blood electrolyte and metabolic disturbances with appropriate i.v. hydrating solutions, anaesthesia was induced with propofol and suxamethonium. Infants were divided in two groups according to the volatile anaesthetic agent used for maintenance of anaesthesia after tracheal intubation: halothane (n = 16) or isoflurane (n = 15). The two groups were identical regarding weight (4.28 +/- 0.6 vs 4.14 +/- 0.76 kg), age (1.6 +/- 0.9 vs 1.5 +/- 0.6 months), preinduction heart rate (155 +/- 22 vs 151 +/- 22 b.min-1) and systolic-diastolic arterial pressure (96 +/- 18/58 +/- 12 vs 105 +/- 16/67 +/- 15 mmHg). Propofol and suxamethonium doses were identical, 3.9 +/- 1 mg.kg-1 and 1.3 +/- 0.6 mg.kg-1 respectively in halothane group, vs 4.3 +/- 0.8 mg.kg-1 and 1.3 +/- 0.4 mg.kg-1 in isoflurane group. Heart rate did not change after induction of anaesthesia, while arterial blood pressure decreased significantly (p < 0.001). However, blood pressure remained within the normal range for age throughout the procedure. Mean duration of surgery was shorter in halothane group (64 +/- 16 vs 79 +/- 17 min, p < 0.05), however time-interval from the end of surgery to tracheal extubation (12 +/- 6 vs 15 +/- 8 min) was short and identical in the two groups.(ABSTRACT TRUNCATED AT 250 WORDS)