Current management of hypertrophic pyloric stenosis

Diagnostic Accuracy of Acid-Base Status in Infants with Hypertrophic Pyloric Stenosis

Background: Hypertrophic pyloric stenosis is a condition in newborns in which the hypertrophic pyloric muscle causes gastric obstructive symptoms of progressive vomiting leading to hypochloremic hypokalemic metabolic alkalosis. The main aim of the research was to assess whether, based on the acid-base status, we can distinguish newborns who vomit due to pylorostenosis, compared with newborns who vomit for other unspecific reasons. Methods: The electronic records of patients in the hospital information system treated under the diagnosis Q40.0 (Congenital hypertrophic pyloric stenosis) (n = 69/included in the study = 53) in the period from 1 January 2014 to 1 January 2022 were reviewed retrospectively. For the purposes of the control group, the electronic records of patients treated in the emergency department with a diagnosis of R11.0 (Nausea and vomiting) (n = 53) without an established cause were randomly reviewed. In addition to the main aim, other research outcomes were to determine differences between groups in the following variables: duration of symptoms, family history, birth (preterm, term, post-term), birth weight, weight during examination, difference between birth weight and weight during an examination, type of vomiting, the thickness of the muscle wall and its length, and to calculate whether there is a correlation between the thickness and length of the pylorus muscle and the duration of vomiting in relation to variables from acid-base status. Results: In relation to the variables of interest between the groups, statistically significant differences were observed in the duration of symptoms (Mdn 4 vs. 2 days, p = 0.002), weight at examination (Mean 3880 vs. 4439 g, p = 0.001), difference in weight between birth and examination (Mean 374 vs. 1010 g, p < 0.0001), and type of vomiting (explosive 45 vs. 22, p = 0.023). In the acid-base status between the groups, a statistically significant difference was recorded for pH (Mdn 7.457 vs. 7.422, p < 0.0001), bicarbonate (Mdn 25 vs. 23 mmol/L, p = 0.000), total carbon dioxide (Mdn 25 vs. 24 mmol/L, p = 0.011), base excess (Mdn 0.8 vs. −1.3 mmol/L, p = 0.000), potassium (Mdn 5 vs. 5.3 mmol/L, p = 0.006), ionized calcium (Mdn 1.28 vs. 1.31 mmol/L, p = 0.011), and glucose (Mdn 4.5 vs. 4.9 mmol/L, p = 0.007). Regardless of the group, the correlations between the duration of vomiting (r = 0.316, p = 0.021 vs. r = 0.148, p = 0.290) and the thickness (r = 0.190, p = 0.172) and length (r = 0.142, p = 0.311) of the pylorus muscle in relation to pH did not exist or were weak. Conclusions: In a world where radiological methods are not equally available everywhere, with promising acid-base indicators, prospective multicenter studies and meta-analyses must be pursued in the future in order not to miss the possible much greater diagnostic potential of acid-base status.

Controlled long term outcome of pyloromyotomy for pyloric stenosis: No long-term adverse effect

PURPOSE

Pyloromyotomy for pyloric stenosis is one of the more common surgical procedures performed on infants. The long-term effects of the procedure are however unclear. The purpose of this study was to study the effects into adult life, compare them with controls and to see if there is a need for structured follow up of patients.

METHODS

Of the 101 patients operated for pyloric stenosis between 1972 and 1974 at our tertiary referral center 91 could be traced. They were all invited to participate in the study and were sent validated questionnaires (PAGI-SYM, GIQLI) as well as a study-specific questionnaire examining the use of antacid drugs, incidence of gastroscopy and abdominal surgery. Sixty patients responded (66%, mean age 45 years, 46 male) and were included. Thereafter, 600 age and sex-matched controls were sent the same questionnaires. 132 responded (22%, 90 male) and were includes as controls.

RESULTS

No significant differences could be found in any of the examined parameters when looking at the whole material or the male patients. Female patients had higher PAGI-SYM-scores for post prandial fullness (mean 1.11 vs 0.43, P = 0.035) and heartburn (mean 0.59 vs 0.14, P = 0.043) when compared to controls.

CONCLUSIONS

The present study shows that most patients operated for pyloric stenosis during infancy experience no negative effects into adulthood. The finding in the female patient group is interesting but is unlikely to have any clinical implications. The results from this study strongly implicate that there is no need for follow up of patients into adulthood.

LEVEL OF EVIDENCE

Level III.

Recurrent Infantile Hypertrophic Pyloric Stenosis in the Emergency Department: A Case Report

INTRODUCTION

Infantile hypertrophic pyloric stenosis (IHPS) is a common cause of infant vomiting. Emergency department (ED) diagnosis is usually made by pyloric ultrasound and treated by pyloromyotomy.

CASE REPORT

An eight-week-old boy with a history of IHPS about six weeks status post pyloromyotomy presented to the ED with vomiting and failure to thrive, and a critically narrowed pylorus was identified by ultrasound. An upper gastrointestinal series confirmed recurrent pyloric stenosis, necessitating another pyloromyotomy.

CONCLUSION

Prolonged vomiting after pyloromyotomy should be concerning for recurrent IHPS. Upper gastrointestinal series should augment ultrasound to diagnose recurrent IHPS and determine whether a second pyloromyotomy is warranted.

Evaluation of a fluid resuscitation protocol for patients with hypertrophic pyloric stenosis

INTRODUCTION

We previously developed an institutional, evidence-based fluid resuscitation protocol for neonates with infantile hypertrophic pyloric stenosis (HPS) based on the severity of electrolyte derangement on presentation. We aim to evaluate this protocol to determine its efficacy in reducing the number of preoperative lab draws, time to electrolyte correction, and overall length of stay.

METHODS

A single center, retrospective review of 319 infants with HPS presenting with electrolyte derangement from 2008 to 2020 was performed; 202 patients managed pre-protocol (2008-2014) and 117 patients managed per our institutional fluid resuscitation algorithm (2016-2020). The number of preoperative lab draws, time to electrolyte correction, and length of stay before and after protocol implementation was recorded.

RESULTS

Use of a fluid resuscitation algorithm decreased the number of infants who required four or more preoperative lab draws (20% vs. 6%) (p < .01), decreased median time to electrolyte correction between the pre and post protocol cohorts (15.1 h [10.6, 22.3] vs. 11.9 h [8.5, 17.9]) (p < .01), and decreased total length of hospital stay (49.0 h [40.3, 70.7] vs. 45.7 h [34.3, 65.9]) (p < .05).

CONCLUSION

Implementation of a fluid resuscitation algorithm for patients presenting with hypertrophic pyloric stenosis decreases the frequency of preoperative lab draws, time to electrolyte correction, and total length of hospital stay. Use of a fluid resuscitation protocol may decrease discomfort through fewer preoperative lab draws and shorter length of stay while setting clear expectations and planned intervention for parents.

LEVEL OF EVIDENCE

III - Retrospective comparative study.

Diagnostic accuracy of palpation and ultrasonography for diagnosing infantile hypertrophic pyloric stenosis: a systematic review and meta-analysis

Objective:

Although infantile hypertrophic pyloric stenosis (IHPS) is a well-known disease, there is no systematic review regarding the optimal diagnostic strategy. We conducted a systematic review and meta-analysis to obtain diagnostic accuracy of all methods to diagnose IHPS.

Methods:

According to the Preferred Reported Items for Systematic Reviews and Meta-Analysis guidelines, we searched MEDLINE and Embase to identify studies reporting sensitivity and specificity of all methods used to diagnose IHPS. Inclusion criteria were infants with suspicion of/or diagnosed with IHPS who underwent pyloromyotomy or had clinical follow-up. A random-effects model was used to obtain pooled estimates of sensitivity, specificity and area under the receiver operating characteristic curve.

Results:

After screening 5364 studies, we included 43 studies with in total 6085 infants (n = 4241 IHPS; n = 1844 controls). The diagnostic sensitivity of palpation ranged from 10.0 to 93.4% and decreased over time. Different parameters for ultrasonography were found. Most used parameters were pyloric muscle thickness (PMT) ≥ 3 mm (pooled sensitivity 97.6% and specificity 98.8%), PMT ≥ 4 mm (pooled sensitivity 94.0% and specificity 98.0%) or a combination of PMT ≥ 4 mm and/or pyloric canal length ≥16 mm (pooled sensitivity 94.0% and specificity 91.7%). The AUC showed high diagnostic accuracy (0.997, 0.966 and 0.981 respectively), but large heterogeneity exists. Due to the large differences in cut-off values no meta-analysis could be conducted for pyloric canal length and pyloric diameter.

Conclusion:

Palpation has limited sensitivity in diagnosing IHPS. We showed that ultrasonography has highest diagnostic accuracy to diagnose IHPS and we advise to use PMT ≥ 3 mm as cut-off.

Advances in knowledge:

This is the first systematic review and meta-analysis on diagnosing IHPS, which summarizes the available literature and may be used as a guideline.

Is there any benefit with pantoprazole treatment in infantile hypertrophic pyloric stenosis?

CONTEXT

Previous studies demonstrated faster correction of metabolic derangement associated with hypertrophic pyloric stenosis with pre-operative intravenous (IV) histamine-2 receptor antagonists.

AIMS

We investigated if similar outcomes are achieved with IV pantoprazole, a proton-pump inhibitor (PPI), including the subgroup of delayed presenters in the South African setting.

SETTINGS AND DESIGN

A 5-year retrospective record review (January 2014-December 2018) compared the rate of metabolic correction in patients with hypertrophic pyloric stenosis at two tertiary centres.

SUBJECTS AND METHODS

One centre routinely administers IV pantoprazole (1 mg/kg daily) preoperatively (PPI group) and the other does not (non-PPI group). Fluid administration, chloride supplementation and post-operative emesis were evaluated.

STATISTICAL ANALYSIS

Spearman's rank correlation coefficient was used to calculate statistical significance for discrete dependent variables. Continuous variables were compared between the groups using the Student t-test. Fisher's exact contingency tables were used to classify categorical data and to assess the significance of outcome between two treatment options. P < 0.05 was considered statistically significant.

RESULTS

Forty-two patients received IV pantoprazole and 24 did not. The mean time of metabolic correction was 8 h shorter in the PPI group (P = 0.067). Total pre-operative chloride administration correlated to the rate of metabolic correction in both cohorts (P < 0.0001). Profound hypochloraemia (chloride <85 mmol/l) was corrected 23 h faster in the PPI group (P < 0.004). Post-operative emesis was noted: 0.45 episodes/patient in the PPI group and 0.75 episodes/patient in the non-PPI group (P = 0.01).

CONCLUSIONS

Pre-operative IV pantoprazole administration showed a faster correction of metabolic derangements, and in profound hypochloraemia, the correction occurred substantially faster in the PPI group. Post-operative emesis was significantly less frequent in the PPI group.

The Dutch Incidence of Infantile Hypertrophic Pyloric Stenosis and the Influence of Seasons

INTRODUCTION

 Studies report contradicting results on the incidence of infantile hypertrophic pyloric stenosis (IHPS) and its association with seasons. We aim to assess the IHPS incidence in the Netherlands and to determine whether seasonal variation is present in a nationwide cohort.

MATERIALS AND METHODS

 All infants with IHPS hospitalized in the Netherlands between 2007 and 2017 were included in this retrospective cohort study. Incidence rates per 1,000 livebirths (LB) were calculated using total number of LB during the matched month, season, or year, respectively. Seasonal variation based on month of birth and month of surgery was analyzed using linear mixed model and one-way ANOVA, respectively.

RESULTS

 A total of 2,479 infants were included, of which the majority was male (75.9%). Median (interquartile range) age at surgery was 34 (18) days. The average IHPS incidence rate was 1.28 per 1,000 LB (variation: 1.09-1.47 per 1,000 LB). We did not find a conclusive trend over time in IHPS incidence. Differences in incidence between season of birth and season of surgery were not significant (p = 0.677 and p = 0.206, respectively).

CONCLUSION

 We found an average IHPS incidence of 1.28 per 1,000 LB in the Netherlands. Our results showed no changing trend in incidence and no seasonal variation.

Hypertrophic Pyloric Stenosis

Hypertrophic pyloric stenosis is a common condition seen in the first 1 to 3 months after birth. Patients typically present with nonbilious projectile emesis after feeds that may result in hypokalemic, hypochloremic metabolic alkalosis. Although inability to tolerate feeds is frequently seen with self-limited conditions such as reflux, a low threshold to obtain an ultrasonographic image is important to prevent a delay in diagnosis. Although operative intervention is the treatment, it is imperative that patients are hydrated and serum electrolyte concentrations normalized before the induction of anesthesia. Laparoscopic pyloromyotomy is safe and effective. Postoperative emesis is normal, and reassurance to parents is appropriate. There is no significant long-term physiologic impairment from pyloric stenosis after successful surgical intervention.

Management of Postoperative Complications Following Common Pediatric Operations

This review discusses complications unique to pediatric surgical populations. Here the authors focus primarily on five of the most common procedures performed in children: appendectomy, central venous catheterization, pyloromyotomy, gastrostomy, and inguinal/umbilical hernia repair.

Brief Overview and Updates on Infantile Hypertrophic Pyloric Stenosis: Focus on Perioperative Management

Infantile hypertrophic pyloric stenosis is the most common surgical cause of vomiting in infancy. After adequate resuscitation, surgical pyloromyotomy is the standard of care for infants with pyloric stenosis. This article provides a brief overview and updates on hypertrophic pyloric stenosis in infants, with a focus on the surgical approach as well as perioperative management of this pathology. The most controversial aspect of the management of infants with pyloric stenosis is post-pyloromyotomy feeding, as there is no clear consensus in the literature on the best regimen. More randomized controlled trials are needed to establish the optimal resuscitation protocol in the preoperative phase and the ideal feeding regimen in the postoperative phase for infants with hypertrophic pyloric stenosis. [Pediatr Ann. 2021;50:(3):e136-e141.].

Respiratory problems owing to severe metabolic alkalosis in infants presenting with hypertrophic pyloric stenosis

OBJECTIVE

Uncorrected metabolic alkalosis in infantile hypertrophic pyloric stenosis (IHPS) could lead to perioperative apnea. However, the precise incidence of preoperative respiratory problems and the association with metabolic alkalosis are unknown. Therefore, we aimed to determine the incidence of preoperative respiratory problems in IHPS and to assess the association with metabolic alkalosis.

METHODS

We retrospectively reviewed all patients diagnosed with IHPS during 2007-2017. Respiratory problems were classified as present or absent. With multivariate logistic regression we analyzed the association between bicarbonate and respiratory problems, corrected for gestational age and birth weight.

RESULTS

We included 459 infants, of whom 23 developed preoperative respiratory problems (5.0%). Infants with preoperative respiratory problems were more often female (43.5% vs. 13.3% p = 0.001) and had significantly higher median serum levels of bicarbonate (32.0 mmol/L vs. 30.0 mmol/L), base excess (6.5 mmol/L vs. 5.3 mmol/L) and pCO2 (6.4 kPa vs. 5.9 kPa), compared to infants without respiratory problems. Multivariate analysis of serum bicarbonate and presence of respiratory problems showed an OR of 2.18 per 10 mmol/L (95% CI 1.21-4.71) (p = 0.009). The optimal bicarbonate cutoff point was 25.7 mmol/L (sensitivity 100%, specificity 13.4%).

CONCLUSION

IHPS with metabolic alkalosis potentially results in preoperative respiratory problems. A lower bicarbonate target before surgery might be recommended and respiratory monitoring should be considered.

LEVEL OF EVIDENCE

Level IV.

A Delphi Analysis to Reach Consensus on Preoperative Care in Infants with Hypertrophic Pyloric Stenosis

INTRODUCTION

 Infantile hypertrophic pyloric stenosis (IHPS) is a common gastrointestinal condition that can lead to metabolic alkalosis and, if uncorrected, to respiratory complications. A standardized approach to correct metabolic derangements and dehydration may reduce time until pyloromyotomy while preventing potential respiratory complications. Such an evidence-based policy regarding preoperative care is absent. We aim to formulate a recommendation about preoperative care for infants with IHPS using the Delphi technique.

MATERIALS AND METHODS

 The RAND/UCLA appropriateness method was used to reach international consensus in a panel of pediatric surgeons, pediatric anesthetists, and pediatricians. Statements on type and frequency of blood sampling, required serum concentrations before pyloromyotomy and intravenous fluid therapy, were rated online using a 9-point Likert scale. Consensus was present if the panel rated the statement appropriate/obligatory (panel median: 7-9) or inappropriate/unnecessary (panel median: 1-3) without disagreement according to the interpercentile range adjusted for symmetry formula.

RESULTS

 Thirty-three and twenty-nine panel members completed the first and second round, respectively. Consensus was reached in 54/74 statements (73%). The panel recommended the following laboratory tests and corresponding cutoff values prior to pyloromyotomy: pH ≤7.45, base excess ≤3.5, bicarbonate <26 mmol/L, sodium ≥132 mmol/L, potassium ≥3.5 mmol/L, chloride ≥100 mmol/L, and glucose ≥4.0 mmol/L. Isotonic crystalloid with 5% dextrose and 10 to 20 mEq/L potassium should be used for fluid resuscitation.

CONCLUSION

 Consensus is reached in an expert panel about assessment of metabolic derangements at admission, cutoff serum concentrations to be achieved prior to pyloromyotomy, and appropriate intravenous fluid regime for the correction of dehydration and metabolic derangements in infants with IHPS.

Guidelines of the Italian Society of Videosurgery (SIVI) in Infancy for the minimally invasive treatment of Hypertrophic Pyloric Stenosis in neonates and infants

The most appropriate treatment for the infantile Hypertrophic Pyloric Stenosis (HPS) is still debated. The non-surgical conservative treatment with oral or intravenous administration of atropine does not enjoy a widespread appreciation for several factors (...).

The Safety and Effectiveness of Laparoscopic versus Open Surgery for Congenital Hypertrophic Pyloric Stenosis in Infants

BACKGROUND This study aimed to investigate the safety and effectiveness of laparoscopic pyloromyotomy for infants with congenital hypertrophic pyloric stenosis. MATERIAL AND METHODS The clinical data of 233 infants with congenital hypertrophic pyloric stenosis who were treated at our hospital from January 2013 to January 2018 were analyzed retrospectively. The patients were divided into 2 groups: the laparoscopic group (group A, n=126) and the conventional operation group (group B, n=107). RESULTS Laparoscopic surgery was successfully performed in all patients in the laparoscopic group, and none of the surgeries were converted to open surgery. Compared with traditional surgery, laparoscopic surgery has obvious advantages in operation time (29.8±12.9 minutes versus 37.2±17.5 minutes, P=0.012), postoperative feeding time (10.3±2.2 hours versus 15.2±4.1 hours, P=0.035), postoperative hospitalization time (2.8±0.7 days versus 3.5±1.9 days, P=0.013), incision length (0.9±0.2 cm versus 3.3±0.8 cm, P=0.002) and poor wound healing (0 versus 6, P=0.007). No complications, such as bleeding, gastric perforation, duodenal injury, abdominal infection or recurrent vomiting, were observed in the 2 groups. The growth and development (weight and height) of the infants in both groups were normal. CONCLUSIONS Laparoscopic pyloromyotomy has the same safety and effectiveness as the traditional operation and has the advantages of less trauma, faster recovery and cosmetically pleasing incisions.

Comparison of laparoscopic and open pyloromyotomy: Concerns for omental herniation at port sites after the laparoscopic approach

Pyloromyotomy is a common surgical procedure in infants with hypertrophic pyloric stenosis and can be performed with a small laparotomy or laparoscopically. No specific complications have been documented about one of the approaches. We aim to study (severity of) complications of pyloromyotomy and to compare complications of both approaches. Children undergoing pyloromyotomy between 2007 and 2017 were analyzed retrospectively. Complication severity was classified using the Clavien-Dindo classification. We included 474 infants (236 open; 238 laparoscopic). 401 were male (85%) and median (IQR) age was 33 (19) days. There were 83 surgical complications in 71 patients (15.0%). In the open group 45 infants (19.1%) experienced a complication vs. 26 infants in the laparoscopic group (10.5%)(p = 0.013). Severity and quantity of postoperative complications were comparable between both groups. Serosal tears of the stomach (N = 19) and fascial dehiscence (N = 8) occurred only after open pyloromyotomy. Herniation of omentum through a port site occurred only after laparoscopy (N = 6) and required re-intervention in all cases. In conclusion, the surgical complication rate of pyloromyotomy was 15.0%. Serosal tear of the stomach and fascial dehiscence are only present after open pyloromyotomy and omental herniation after laparoscopy respectively. The latter complication is underestimated and requires attention.

Risk factors for unsuccessful atropine therapy in hypertrophic pyloric stenosis

BACKGROUND

I.v. atropine (IA) for infantile hypertrophic pyloric stenosis (IHPS) is a good alternative to pyloromyotomy but has not been broadly accepted. The lower success rate is one of the greatest disadvantages of IA. We investigated the risk factors for unsuccessful results following IA for IHPS.

METHODS

Medical records of patients with IHPS who were admitted to Kimitsu Chuo Hospital between 2002 and 2016 and were initially given atropine sulfate were retrospectively reviewed. Atropine was given i.v. (0.1 mg/kg/day in eight divided doses). Oral feeding of milk was started with a small amount and increased in a stepwise fashion to full feed. IA therapy was defined as unsuccessful in the presence of projectile vomiting more than three times a day or intolerance to a predetermined amount of milk.

RESULTS

Of the 48 patients with IHPS, 33 patients were successfully treated with IA and 15 patients needed surgical intervention. On univariate analysis the risk factors for unsuccessful IA therapy were younger age, lower bodyweight, and shorter duration of symptoms before diagnosis. On multivariate analysis age at diagnosis < 30 days was the only significant risk factor for unsuccessful IA therapy (OR, 5.7 l P = 0.03).

CONCLUSIONS

Age at diagnosis < 30 days is a risk factor for unsuccessful IA therapy in IHPS. This might be considered when IA therapy is used for neonates with IHPS.

Developmental outcome at 3 years of age of infants following surgery for infantile hypertrophic pyloric stenosis

PURPOSE

The study compared neurodevelopmental outcome at 3 years of age of infants with infantile hypertrophic pyloric stenosis (IHPS) who underwent pyloromyotomy with healthy control infants in New South Wales, Australia.

METHODS

Infants with IHPS as well as controls were recruited between August 2006 and July 2008. Developmental assessments were performed using the Bayley scales of infant and toddler development (version III) (BSITD-III) at 1 and 3 years of age.

RESULTS

Of the 43 infants originally assessed at 1 year, 39 returned for assessment at 3 years (90%). The majority were term infants (77%). Assessments were also performed on 156 control infants. Infants with IHPS scored significantly lower on four of the five Bayley subsets (cognitive, receptive and expressive language and fine motor) compared to control infants. Analysis of co-variance showed statistically significant results in favour of the control group for these four subsets.

CONCLUSION

Compared with the outcomes at 1 year, infants with IHPS at 3 years of age continue to score below controls in four of the BSITD-III subscales. This suggests they should have developmental follow-up with targeted clinical intervention. There is a need for further studies into functional impact and longer term outcomes.

Venous Physiology Predicts Dehydration in the Pediatric Population

BACKGROUND

No standard dehydration monitor exists for children. This study attempts to determine the utility of Fast Fourier Transform (FFT) of a peripheral venous pressure (PVP) waveform to predict dehydration.

MATERIALS AND METHODS

PVP waveforms were collected from 18 patients. Groups were defined as resuscitated (serum chloride ≥ 100 mmol/L) and hypovolemic (serum chloride < 100 mmol/L). Data were collected on emergency department admission and after a 20 cc/kg fluid bolus. The MATLAB (MathWorks) software analyzed nonoverlapping 10-s window signals; 2.4 Hz (144 bps) was the most demonstrative frequency to compare the PVP signal power (mmHg).

RESULTS

Admission FFTs were compared between 10 (56%) resuscitated and 8 (44%) hypovolemic patients. The PVP signal power was higher in resuscitated patients (median 0.174 mmHg, IQR: 0.079-0.374 mmHg) than in hypovolemic patients (median 0.026 mmHg, IQR: 0.001-0.057 mmHg), (P < 0.001). Fourteen patients received a bolus regardless of laboratory values: 6 (43%) resuscitated and 8 (57%) hypovolemic. In resuscitated patients, the signal power did not change significantly after the fluid bolus (median 0.142 mmHg, IQR: 0.032-0.383 mmHg) (P = 0.019), whereas significantly increased signal power (median 0.0474 mmHg, IQR: 0.019-0.110 mmHg) was observed in the hypovolemic patients after a fluid bolus at 2.4 Hz (P < 0.001). The algorithm predicted dehydration for window-level analysis (sensitivity 97.95%, specificity 93.07%). The algorithm predicted dehydration for patient-level analysis (sensitivity 100%, specificity 100%).

CONCLUSIONS

FFT of PVP waveforms can predict dehydration in hypertrophic pyloric stenosis. Further work is needed to determine the utility of PVP analysis to guide fluid resuscitation status in other pediatric populations.

Pyloric stenosis: an enigma more than a century after the first successful treatment

Despite hypertrophic pyloric stenosis (HPS) being one of the most frequently treated pediatric surgical conditions, its etiology remains incompletely understood. We review the diagnosis and treatment of this condition with an emphasis on the evolution of surgical techniques that led to laparoscopic pyloromyotomy, the most frequently performed technique for HPS today. In addition, we review key developments in the understanding of HPS etiology and treatment, including the postulated etiology of work-induced hypertrophy of the pylorus, its association with prokinetic macrolide antibiotics, and the emerging role of atropine sulfate as a medical treatment for HPS or a rescue treatment for incomplete myotomy.

The treatment of pyloric stenosis: Evolution in practice

Over the last hundred years, idiopathic hypertrophic pyloric stenosis has undergone an evolution in treatment, with subsequent improvements in outcome. Initially, it was treated by physicians with antispasmodics and various alternative feeding and resuscitation modalities. The evolution of surgical approaches led to a revolution in outcome, from almost certain death to complete cure. The progression of surgical and medical treatments is reviewed in this article until, ultimately, Ramstedt's pyloromyotomy is reached. This distilled operation has remained the gold-standard procedure for over a century.

Successful combination of endoscopic pyloromyotomy and balloon dilatation for hypertrophic pyloric stenosis in an older child: A novel procedure

Background

Hypertrophic pyloric stenosis (HPS) is a rare cause of gastric outlet obstruction beyond infancy. Ramstedt pyloromyotomy remains the gold standard treatment for HPS. This type of HPS can be managed successfully with pyloromyotomy under laparoscopic or open procedures. Endoscopic pyloric balloon dilation (EPBD) has not been recommended in the treatment of HPS, and there are only a small number of reported cases who had had successful endoscopic pyloromyotomy (EP) for HPS only in infants.

Case presentation

The patient was suspected of having HPS when the patient was 1 year old after infancy. However, his parents thought that the vomiting and poor sucking were caused by Down syndrome-associated muscular hypotonia. Since then, no additional tests have been performed at their request. At 6 years of age, he was readmitted to our department because of persistent vomiting and failure to thrive, and HPS was diagnosed again. However, it was unknown whether the HPS had been persisting since infancy or was acquired. The first EPBD was slightly effective but did not remain effective for a long time. When the second EPBD was performed in combination with EP, the amount and frequency of vomiting were reduced dramatically.

Conclusions

The combination of EP and EPBD procedure may represent a safe, effective, and minimally invasive option for selected HPS patients in whom laparotomy would pose a significant risk or who do not respond to conventional medical treatment. To our knowledge, this is the first report to describe combination treatment with EP and EPBD in an older child with HPS.

Non-laparoscopic minimal surgical approach to pyloromyotomy: An experience from a challenged resource setting

BACKGROUND

The aim of the study is to review the experience with the classic Ramstedt's pyloromyotomy through the RUQ approach and the circumlinear supraumbilical fold approach (circumumbilical [CU]) pyloromyotomy (an approach that combines the ease and safety of the open pyloromyotomy with the advantages of minimal invasiveness).

PATIENTS AND METHODS

A single centre review in a period of 12 years from January 2001 to December 2013 with the institutional ethical committee's approval, evaluating 316 pyloromyotomies based on surgical approach: RUQ (171); and CU (145). Patients' demographics, acid-base/electrolyte status on presentation, mean operative time (MOT), postoperative length of stay (LOS) at hospital, and complications were recorded.

RESULTS

Patients demographics, acid - base/electrolyte status on presentation; and MOT were not significantly different. The median LOS was 33 and 30 minutes for CU and RUQ, respectively, with no statistical significant difference between the two groups. One patient in the CU group had a late adhesive bowel obstruction requiring laparotomy and bowel resection. Moreover, wound infection rates did not differ significantly between the two groups (CU 3; and RUQ; 3; P = 0.15).

CONCLUSIONS

Pyloromyotomy is associated with a low complication rate. Cosmetically, CU is superior to the RUQ approach. Its short learning curve and the feasibility to examine the integrity of the duodenal mucosa intraoperatively may make CU a safer alternative in case of surgeons who are still practicing the RUQ approach in countries with a challenged resource settings.

Contemporary management of pyloric stenosis

Hypertrophic pyloric stenosis is a common surgical cause of vomiting in infants. Following appropriate fluid resuscitation, the mainstay of treatment is pyloromyotomy. This article reviews the aetiology and pathophysiology of hypertrophic pyloric stenosis, its clinical presentation, the role of imaging, the preoperative and postoperative management, current surgical approaches and non-surgical treatment options. Contemporary postoperative feeding regimens, outcomes and complications are also discussed.

Implementation of a care pathway for infantile hypertrophic pyloric stenosis reduces length of stay and increases parent satisfaction

Introduction

Infantile hypertrophic pyloric stenosis (IHPS) is a common surgical condition, but there are no guidelines regarding preoperative fluid resuscitation. Our aim was to evaluate a novel consensus care pathway for IHPS, incorporating a standardized fluid and electrolyte replacement regime.

Methods

One hundred patients were initially reviewed and compared to thirty-three patients following the introduction of a clinical pathway, whereby infants requiring electrolyte correction received 150 ml/kg/24 h of 0.45% saline, 5% dextrose and 10 mmol KCl, with systematic blood sampling until correction was achieved. We measured time to electrolyte correction, time to surgery and total length of hospitalization. Data were described using the median and interquartile range, and differences between the groups’ categorical and continuous data were described using Chi-squared and the Mann–Whitney U–tests, respectively.

Results

Time in hours taken to correct electrolytes was reduced: 25(16.5–42) versus 9.5(4.5–24.75) p = 0.004. Time to surgery from admission in uncorrected patients decreased from 50(40.25–66.75) to 39(28.75–41.75) p = 0.018. Subsequently, there was a reduction in total length of stay: 94(71–93.5) versus 75(64.5–93.5) p = 0.025. Parental satisfaction increased from 77% in the pre-pathway group to 83% in the pathway group.

Conclusion

A consensus care pathway for IHPS reduces the time taken to correct preoperative electrolyte abnormalities, decreases length of hospitalization and improves parental satisfaction.

Maternal factors in the origin of infantile hypertrophic pyloric stenosis: A population-based case-control study

In most patients affected by isolated infantile hypertrophic pyloric stenosis (IHPS) the etiology is largely unknown. Thus, the aim of this study was to estimate possible maternal risk factors in the origin of IHPS. The study samples included 241 cases with IHPS, 357 matched controls and 38,151 population controls without any defect in the population-based large dataset of the Hungarian Case-Control Surveillance of Congenital Abnormalities, 1980-1996. Exposures that had been medically recorded in prenatal maternity logbooks during the critical period of IHPS were evaluated separately. The findings of this case-control study suggested that--beyond the well-known robust male excess (85.5%)--maternal hyperthyroidism (OR with 95% CI: 4.17, 1.53-11.38) and oral nalidixic acid treatment (OR with 95% CI: 6.53, 3.03-14.06) associated with a higher risk for IHPS in their children. In conclusion, our findings suggest that cases with IHPS had mothers with a higher proportion of hyperthyroidism and nalidixic acid treatment during pregnancy.

Feeding Post-Pyloromyotomy: A Meta-analysis

CONTEXT

Postoperative emesis is common after pyloromyotomy. Although postoperative feeding is likely to be an influencing factor, there is no consensus on optimal feeding.

OBJECTIVE

To compare the effect of feeding regimens on clinical outcomes of infants after pyloromyotomy.

DATA SOURCES

Cumulative Index to Nursing and Allied Health Literature, The Cochrane Central Register of Controlled Trials, Embase, and Medline.

STUDY SELECTION

Two reviewers independently assessed studies for inclusion based on a priori inclusion criteria.

DATA EXTRACTION

Data were extracted on methodological quality, general study and intervention characteristics, and clinical outcomes.

RESULTS

Fourteen studies were included. Ad libitum feeding was associated with significantly shorter length of stay (LOS) when compared with structured feeding (mean difference [MD] -4.66; 95% confidence interval [CI], -8.38 to -0.95; P = .01). Although gradual feeding significantly decreased emesis episodes (MD -1.70; 95% CI, -2.17 to -1.23; P < .00001), rapid feeding led to significantly shorter LOS (MD 22.05; 95% CI, 2.18 to 41.93; P = .03). Late feeding resulted in a significant decrease in number of patients with emesis (odds ratio 3.13; 95% CI, 2.26 to 4.35; P < .00001).

LIMITATIONS

Exclusion of non-English studies, lack of randomized controlled trials, insufficient number of studies to perform publication bias or subgroup analysis for potential predictors of emesis.

CONCLUSIONS

Ad libitum feeding is recommended for patients after pyloromyotomy as it leads to decreased LOS. If physicians still prefer structured feeding, early rapid feeds are recommended as they should lead to a reduced LOS.

Infantile hypertrophic pyloric stenosis at a tertiary care hospital in Tanzania: a surgical experience with 102 patients over a 5-year period

Background

Infantile hypertrophic pyloric stenosis (IHPS) is the most common cause of gastric outlet obstruction in infants. There is paucity of published data regarding this condition in our setting. This study describes the clinical presentation, mode of treatment and outcome of treatment of this disease and identifies factors responsible for poor outcome of these patients.

Methods

This was a descriptive retrospective study of infants with HPS admitted to Bugando Medical Centre and subsequently underwent surgery between February 2009 and January 2014.

Results

A total of 102 patients (M:F = 4.7:1) were studied. The median age at presentation was 5 weeks. The median duration of illness was 4 weeks. Fifty-four (52.9 %) patients occur in first-born children. Associated anomalies were reported in 7 (6.9 %) patients. Non-bilious vomiting was the most frequent symptom and it was described in all (100 %) patients. A palpable mass was found in 23.5 % of infants. The diagnosis of IHPS was made clinically in 86 (84.3 %) and by ultrasound in 16 (15.7 %) patients. The treatment was Ramstedt’s pyloromyotomy in all cases. There were 6 (5.9 %) intra-operative mucosal perforations which were repaired successively. Postoperative complication was 11.8 %. The median length of hospital stay was 12 days and it was significantly associated with prolonged pre-operative hospitalization (p = 0.001). The mortality rate was 4.9 %. Age below 2 weeks, late presentation (≥14 days), severe dehydration on admission, hypokalaemia on admission and surgical site infection were the main predictors of mortality (p < 0.001).

Conclusion

This study has shown that IHPS is a common condition in our setting. Age <2 weeks, delayed presentation, prolonged preoperative hospital stay, surgical site infection and high proportion of dehydration and electrolyte disturbance were the main predictors of poor outcome. A high index of suspicion is needed in infants with non-bilious vomiting to avoid delay in diagnosis.

Birth outcomes of male and female patients with infantile hypertrophic pyloric stenosis--a population-based case-control study

OBJECTIVE

Most of the patients are affected by isolated infantile hypertrophic pyloric stenosis (IHPS) beyond the polygenic predisposition, the other factors in the multifactorial etiology are largely unknown. The main characteristic of IHPS is the robust male predominance, thus the aim of this study was to analyze birth outcomes in males and females whether they are different or not.

METHODS

The study samples included 241 cases with IHPS, 357 matched, and 38,151 population controls without any defect in the population-based large dataset of the Hungarian Case-Control Surveillance of Congenital Abnormalities, 1980-1996.

RESULTS

The findings of this case-control study confirmed the well-known strong male excess (85.5%). The mean gestational age was somewhat longer and it is associated with a lower rate of preterm births. Mean birth weight did not show significant differences among the study groups, but the rate of low birthweight was higher in cases with IHPS. However, these differences were found only in males. Thus, intrauterine fetal growth restriction is characteristic only for male cases with IHPS.

CONCLUSIONS

Our study confirmed the well-known obvious male excess of cases with IHPS, but our findings suggest some differences in birth outcomes of male and female cases. Male cases with IHPS had intrauterine fetal growth restriction while females did not. These data may indicate some differences in the pathogenesis of IHPS in males and females.

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.

Emergencies in pediatric surgery

Primary care physicians are often required to initially manage the children with surgical emergencies. Many neonates with congenital malformations delivered without supervision may also be managed initially by the family physicians. The role of the primary care physician in such cases should be to diagnose the condition correctly, provide immediate care and then refer the newborn or child to higher centre for appropriate management.

Maternal and pregnancy characteristics and risk of infantile hypertrophic pyloric stenosis

BACKGROUND/PURPOSE

The incidence of infantile hypertrophic pyloric stenosis (IHPS) in Sweden decreased dramatically during the 1990s. The aim of the study was to examine IHPS risk factors and the possible change in them as the incidence declined.

METHODS

This is a case-control study including 3608 surgically treated IHPS cases and 17588 matched controls during 1973-2008. Cases were identified in the Swedish National Patient Register and data on possible risk factors were collected from the Swedish Medical Birth Register. The association between study variables and IHPS was analyzed using conditional logistic regression for the whole study period and separately for periods with high and low IHPS incidences.

RESULTS

Prematurity (OR, 2.54; 95% CI, 2.06-3.14), caesarean delivery (OR, 1.67; 95% CI, 1.51-1.86), maternal smoking (OR, 1.82; 95% CI, 1.53-2.16), and young maternal age (< 20yrs) (OR, 1.42; 95% CI, 1.17-1.73) were associated with an increased IHPS risk. Birth order 2 (OR, 0.78; 95% CI, 0.71-0.85) or more was associated with a lower IHPS risk. ORs for smoking increased at low incidence rate.

CONCLUSION

We report caesarean section, prematurity, primiparity, young maternal age, and smoking as significant IHPS risk factors. The impact of smoking was higher during periods with a low incidence.

Advances in infantile hypertrophic pyloric stenosis

Infantile hypertrophic pyloric stenosis (IHPS) is a common condition in infancy, characterized by an acquired narrowing of the pylorus, which requires surgery. These infants usually present with projectile, nonbilious vomiting, with a palpable 'olive' in the abdomen and sometimes a 'peristaltic wave' after being fed with formula or breast milk. Although IHPS is a common disorder, its etiology is largely unknown. Surgical intervention is the standard treatment, preoperative preparation, however is essential to optimal outcome. In this review, the latest advances in IHPS regarding epidemiology, etiology, diagnostics and treatment will be discussed.

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.

Olive without a cause: the story of infantile hypertrophic pyloric stenosis

For many diseases and medical conditions the clinical recognition and the development of accurate diagnostic methods and the etiological cause precede effective treatment. In the case of infantile hypertrophic pyloric stenosis (HPS), this sequence of events did not happen. Clinical recognition of the entity proceeded directly to the development of curative treatment. Reliable diagnostic imaging methods followed, but a definitive etiology has not been elucidated. This paper reviews the historical aspects of hypertrophic pyloric stenosis, discusses how and why it took so long for this not uncommon disease to be recognized, and highlights the physicians who changed an often fatal disease into an easily diagnosed and treated minor affliction.

Should general surgery residents be taught laparoscopic pyloromyotomies? An ethical perspective

OBJECTIVES

The authors examine the ethical implications of teaching general surgery residents laparoscopic pyloromyotomy.

DESIGN/PARTICIPANTS

Using the authors' previously presented ethical framework, and examining survey data of pediatric surgeons in the United States and Canada, a rigorous ethical argument is constructed to examine the question: should general surgery residents be taught laparoscopic pyloromyotomies?

RESULTS

A survey was constructed that contained 24 multiple-choice questions. The survey included questions pertaining to surgeon demographics, if pyloromyotomy was taught to general surgery and pediatric surgery residents, and management of complications encountered during pyloromyotomy. A total of 889 members of the American Pediatric Surgical Association and Canadian Association of Paediatric Surgeons were asked to participate. The response rate was 45% (401/889). The data were analyzed within the ethical model to address the question of whether general surgery residents should be taught laparoscopic pyloromyotomies.

CONCLUSIONS

From an ethical perspective, appealing to the ethical model of a physician as a fiduciary, the answer is no.

DEFINITIONS

We previously proposed an ethical model based on 2 fundamental ethical principles: the ethical concept of the physician as a fiduciary and the contractarian model of ethics. The fiduciary physician practices medicine competently with the patient’s best interests in mind. The role of a fiduciary professional imposes ethical standards on all physicians, at the core of which is the virtue of integrity, which requires the physician to practice medicine to standards of intellectual and moral excellence. The American College of Surgeons recognizes the need for current and future surgeons to understand professionalism, which is one of the 6 core competencies specified by the Accreditation Council for Graduate Medical Education. Contracts are models of negotiation and ethically permissible compromise. Negotiated assent or consent is the core concept of contractarian bioethics. Nonnegotiable goods are goals for residency training that should never be sacrificed or negotiated away. Fiduciary responsibility to the patient, regardless of level of training, should never be compromised, because doing so violates the professional virtue of integrity. The education of the resident is paramount to afford him or her the opportunity to provide competent care without supervision to future patients. Such professional competence is the intellectual and clinical foundation of fiduciary responsibility, making achievement of educational goals during residency training another nonnegotiable good.

Pyloromyotomy versus i.v. atropine therapy for the treatment of infantile pyloric stenosis: nationwide hospital discharge database analysis

BACKGROUND

Several studies have suggested that i.v. atropine has a potential role in treating infantile hypertrophic pyloric stenosis (IHPS). It remains unclear, however, whether surgery can be replaced by i.v. therapy.

METHODS

Data were extracted on infants with IHPS who were treated with atropine and/or surgery, from a nationwide administrative database through 2006-2008. Patient demographic data, treatment effects and length of hospital stay were analyzed in each treatment group.

RESULTS

A total of 585 infants met the criteria for IHPS; 188 patients (32%) were initially treated with atropine (i.v. form, n = 180; oral form, n = 8), while 397 were treated with surgery as a first-line therapy. Of the 180 infants receiving i.v. atropine, 38 were withdrawn from medical management and subsequently underwent surgery. Thus, the overall success rate of i.v. atropine was 78.9% (142/180). Surgery had a success rate of 100%, and postoperative complications were found in 2.8% of patients (12/435). Medical management required longer hospital stay than surgery (mean, 13.5 days vs 8.0 days; P < 0.001).

CONCLUSION

Surgery remains the suitable standard management option for IHPS, with its high success rate, minimal complications and shorter hospital stay compared with i.v. atropine therapy.

Infantile hypertrophic pyloric stenosis: has anything changed?

AIM

The study aims to review the contemporary presentation, diagnosis and treatment of children with infantile hypertrophic pyloric stenosis (IHPS) at an Australian paediatric tertiary centre.

METHODS

A retrospective case review of patients with IHPS presenting to our institution between January 2004 and December 2010 was performed. Results were compared with a previous study evaluating two earlier 6-year series of patients treated between January 1984 and November 1995.

RESULTS

Of 362 infants presenting over the current 7-year review, 84.8% were male. Mean age of admission fell from 5.9 weeks in the previous study to 5.4 weeks. An 'olive' was palpated on examination in 48%, visible peristalsis seen in 25% and 16% of patients presented with haematemesis. Diagnosis solely on clinical examination fell from 74% to 9% and was associated with a corresponding increase in use of ultrasound from 16% to 91%. The frequency of serum chloride values less than 85 mmol/L declined from 26% to 9%. A variety of open and minimally invasive surgical approaches were used with similar outcomes, although laparoscopic pyloromyotomy was associated with significantly higher rates of wound infection (χ(2) = 4.6, P = 0.03). The frequency of major complications remained low at 1%.

CONCLUSION

Contemporary patients with IHPS typically present earlier with a reduction in the incidence of metabolic derangement. Diagnosis based on clinical examination alone appears uncommon, with the majority of suspected cases confirmed by ultrasound. There was no clear difference in overall outcome based on the surgical approach used, although minor variations may reflect our institution's initial experience with laparoscopic pyloromyotomy.

Developmental outcomes following major surgery: what does the literature say?

Relative to the wealth of information in the medical literature regarding developmental outcome for infants who have had cardiac surgery available, few studies specifically detail how those who have undergone major surgery grow and develop. The few published studies tend to be disease specific, making their results difficult to translate to a more general setting. As mortality for most infants who require surgery in infancy continues to decrease, the focus for researchers and clinicians should be on how these children will grow and develop. As parents realise that their infant will survive, this becomes their next major concern. The most common conditions requiring early major surgery have been reviewed in relation to data on infant developmental outcomes.

Hypertrophic pyloric stenosis: predicting the resolution of biochemical abnormalities

PURPOSE

Hypertrophic pyloric stenosis (HPS) is a common condition of infancy, often presenting with marked biochemical derangement, requiring correction. Previous studies have looked at the relationship between serum electrolytes and acid-base balance in HPS but not at the relationship between the degree of biochemical derangement and time taken to resolve the biochemical abnormality.

METHODS

Retrospective analysis was performed on all 151 infants undergoing pyloromyotomy over a 3 year period. Of these, 105 met the inclusion criteria of: compliance with the unit HPS fluid protocol, and the documentation of at least three serial biochemical investigations. The rate of correction for each biochemical marker (sodium, potassium, chloride, urea, pCO2, hydrogen ion concentration, bicarbonate and the base excess) was plotted against the degree of disturbance and then against time.

RESULTS

A significant relationship (P < 0.01) was found between the rate of correction of an abnormal chloride, urea or base excess and the degree of initial derangement. This enables the prediction of the time taken for the required correction of biochemical abnormalities prior to theatre.

CONCLUSION

This method of analysis may be of value in comparing the effectiveness of different fluid regimes in use for the correction of biochemical abnormalities in infants with IHPS.

The changing clinical presentation of hypertrophic pyloric stenosis: the experience of a large, tertiary care pediatric hospital

The authors reviewed the clinical and laboratory data from cases of hypertrophic pyloric stenosis (HPS) diagnosed at their institution from 2006 to 2008. They assessed and compared presentation of patients with HPS over time at their institution. A total of 118 patients were included in this study. An "olive" was palpated in only 13.6% of cases. This is in contrast to older studies, where more than 50% of the patients were reported to have a palpable "olive" depending on when the study was conducted. In patients from this institution, hypochloremia was present in 23% and alkalosis in 14.4%, which are less frequent than the incidence of these abnormalities in older studies. There was a change in the additional "classical" symptoms, represented by the lower percentage of infants in whom an "olive" was palpated and the lower numbers of patients with severe electrolyte imbalances. The reason for this change appears to be the frequent use of ultrasound.