Hypertrophic pyloric stenosis: predicting the resolution of biochemical abnormalities

Perioperative Hypoxemia and Postoperative Respiratory Events in Infants with Hypertrophic Pyloric Stenosis

BACKGROUND

 Normalization of metabolic alkalosis is an important pillar in the treatment of infantile hypertrophic pyloric stenosis (IHPS) because uncorrected metabolic alkalosis may lead to perioperative respiratory events. However, the evidence on the incidence of respiratory events is limited. We aimed to study the incidence of peroperative hypoxemia and postoperative respiratory events in infants undergoing pyloromyotomy and the potential role of metabolic alkalosis.

MATERIALS AND METHODS

 We retrospectively reviewed all patients undergoing pyloromyotomy between 2007 and 2017. All infants received intravenous fluids preoperatively to correct metabolic abnormalities close to normal. We assessed the incidence of perioperative hypoxemia (defined as oxygen saturation [SpO2] < 90% for > 1min) and postoperative respiratory events. Additionally, the incidence of difficult intubations was evaluated. We performed a multivariate logistic regression analysis to evaluate the association between admission or preoperative serum pH values, bicarbonate or chloride, and peri- and postoperative hypoxemia or respiratory events.

RESULTS

 Of 406 included infants, 208 (51%) developed 1 or more episodes of hypoxemia during the perioperative period, of whom 130 (32%) experienced it during induction, 43 (11%) intraoperatively, and 112 (28%) during emergence. About 7.5% of the infants had a difficult intubation and 17 required more than 3 attempts by a pediatric anesthesiologist. Three patients developed respiratory insufficiency and 95 postoperative respiratory events were noticed. We did not find a clinically meaningful association between laboratory values reflecting metabolic alkalosis and respiratory events.

CONCLUSIONS

 IHPS frequently leads to peri- and postoperative hypoxemia or respiratory events and high incidence of difficult tracheal intubations. Preoperative pH, bicarbonate, and chloride were bad predictors of respiratory events.

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.

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.

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.

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 (...).

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.

Corrected to uncorrected? The metabolic conundrum of hypertrophic pyloric stenosis

OBJECTIVES

The purpose of this study was to evaluate factors associated with repeat blood testing after establishment of normal metabolic parameters and factors associated with reversal of metabolic correction back an uncorrected form in preoperative management of infants with Hypertrophic Pyloric Stenosis (HSP).

METHODS

A retrospective review of infants with HSP undergoing repeat serum chemistries after already having normal labs were identified. Variables associated with repeating normal bloodwork and reversion of normal to abnormal labs were identified. Associations between reversion to abnormal and ordering of repeat labs were determined.

RESULTS

255 cases were studied with a median of 2 lab tests drawn per patient (range 1-9). Of 142 serum chemistry tests repeated after a normal test, 27% became abnormal, most commonly hyperkalemia. 61% of these went to surgery. No variables were associated with a normal test becoming abnormal. However, a time lapse of >12h was associated with the reordering of bloodwork despite it already being normal.

CONCLUSIONS

There is little evidence to support need for repeat serum chemistry testing in cases of HPS once normality has been established. Development of clinical pathways to reduce the use of unnecessary serum testing may improve efficiency of patient care and limit unnecessary resource utilization.

LEVEL OF EVIDENCE

Retrospective Case control: 3b.

Optimizing fluid resuscitation in hypertrophic pyloric stenosis

BACKGROUND

Hypertrophic pyloric stenosis (HPS) is the most common diagnosis requiring surgery in infants. Electrolytes are used as a marker of resuscitation for these patients prior to general anesthesia induction. Often multiple fluid boluses and electrolyte panels are needed, delaying operative intervention. We have attempted to predict the amount of IV fluid boluses needed for electrolyte correction based on initial values.

METHODS

A single center retrospective review of all patients diagnosed with HPS from 2008 through 2014 was performed. Abnormal electrolytes were defined as chloride <100mmol/L, bicarbonate ≥30mmol/L or potassium >5.2 or <3.1mmol/L. Patients with abnormal electrolytes were resuscitated with 20ml/kg saline boluses and continuous fluids at 1.5 times maintenance rate.

RESULTS

During the study period 542 patients were identified with HPS. Of the 505 who were analyzed 202 patients had electrolyte abnormalities requiring IV fluid resuscitation above maintenance, and 303 patients had normal electrolytes at time of diagnosis. Weight on presentation was significantly lower in the patients with abnormal electrolytes (3.8 vs 4.1kg, p<0.01). Length of stay was significantly longer in the patients with electrolyte abnormalities, 2.6 vs 1.9days (p<0.01). Fluid given was higher over the entire hospital stay for patients with abnormal electrolytes (106 vs 91ml/kg/d, p<0.01). The number of electrolyte panels drawn was significantly higher in patients with initial electrolyte abnormalities, 2.8 vs 1.3 (p<0.01). Chloride was the most sensitive and specific indicator of the need for multiple saline boluses. Using an ROC curve, parameters of initial Cl(-)80mmol/L and the need for 3 or more boluses AUC was 0.71. Modifying the parameters to initial Cl(-) ≤97mmol/L and 2 boluses AUC was 0.65. A patient with an initial Cl(-)85 will need three 20ml/kg boluses 73% (95% CI 52-88%) of the time. A patient with an initial Cl(-) ≤97 will need two 20ml/kg boluses at a rate of 73% (95% CI 64-80%).

CONCLUSION

Children with electrolyte abnormalities at time of diagnosis of HPS have a longer length of stay; require more fluid resuscitation and more lab draws. This study reveals high sensitivity and specificity of presenting chloride in determining the need for multiple boluses. We recommend the administration of two 20ml/kg saline boluses separated by an hour prior to rechecking labs in patients with initial Cl(-) value ≤97mmol/L. If the presenting Cl(-) <85 three boluses of 20ml/kg of saline separated by an hour are recommended. If implemented these modifications have potential to save time by not delaying care for extraneous lab results and money in the form of fewer lab draws.

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.