Gastric Suctioning to Prevent Iatrogenic Meconium Aspiration

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Gastric Suctioning to Prevent Iatrogenic

Meconium Aspiration

To the Editor.—

The Manual for the Neonatal Resuscitation Program (NRP)1 suggests that the mouth, pharynx, and nose of the newborn and not the stomach be suctioned before delivery of the shoulders, when meconium staining is present. It is suggested that one wait until the infant has been fully resuscitated and vital signs are stable before suctioning the stomach. The reason given for this delay is that the chance of producing a vagal response with apnea and bradycardia will be minimized.

In reviewing the literature, it is difficult to find evidence that gastric suctioning per se causes bradycardia in the fetus and newborn. There is evidence that nasopharyngeal2 _{and tracheal} suctioning3 _{can cause bradycardia in the newborn. However,} when thick meconium is present in the amniotic fluid, most au-thorities agree that upper airway and tracheal suctioning of the newborn are reasonable to prevent or minimize meconium aspi-ration. Because there is such a risk of morbidity and mortality from meconium aspiration, would it not also be reasonable to empty the stomach before endotracheal intubation is performed? Anesthesiologists perform elective intubation in patients who have been fasted for more than eight hours to minimize the risk of regurgitation and aspiration of gastric contents. In an emergency, dorsally directed cricoid pressure is applied to prevent aspiration of gastric contents.4 _{During bag and mask ventilation, cricoid} pressure has also been advocated to prevent gastric distention, which may lead to vomiting.4 _{Logically, similar precautions} should also be taken with newborns who may have swallowed thick meconium in utero.

When suctioned of the upper airway or laryngoscoped, an alert newborn may gag and vomit due to vagal stimulation. Such an occurrence could result in the aspiration of gastric contents con-taining meconium. It thus seems prudent to prevent this poten-tially disastrous complication by emptying the stomach in addi-tion to sucaddi-tioning the upper airway of the newborn delivered through meconium-stained amniotic fluid before the shoulders are delivered and laryngoscopy is performed.

Some newborns require intermittent positive pressure breath-ing (IPPB) after tracheal suctionbreath-ing. Often, a bag and mask system is used to provide this short-term IPPB. Resultant gastric disten-tion further increases the risk of vomiting and aspiradisten-tion and would make previous emptying of the stomach a potentially critically important maneuver.

Gerald H. Katzman, MD

Detroit Riverview Hospital Detroit, MI 48214

REFERENCES

1. Bloom RS, Cropley, AHA/AAP Neonatal Resuscitation Program Steer-ing Committee eds. AAP/AHA Textbook of Neonatal Resuscitation. 3rd ed. American Academy of Pediatrics; 1994:2-13–2-15

2. Cordero L, Hon H. Neonatal bradycardia following nasopharyngeal stimulation. J Pediatr. 1971;78:441– 447

3. Gunderson LP, McPhee AJ, Donovan EF. Partially ventilated endotra-cheal suction. Use in newborns with respiratory distress syndrome.

Am J Dis Child. 1986;140:462– 465

4. Stone D, Gal T. Airway management. In: Miller RD, ed. Anesthesia. 4th ed. New York, Edinburgh, London, Madrid, Melbourne, Milan, Tokyo: Churchill Livingstone; 1994:1418 –1419

In Reply.—

Dr Katzman proposes emptying of the stomach of infants born through meconium-stained amniotic fluid (MSAF) before endo-tracheal intubation of these infants is performed. The rationale is to minimize the risk of regurgitation and aspiration of gastric contents. He proposes “dorsally directed cricoid pressure” during the procedure to prevent aspiration of gastric contents as well as to prevent gastric distention. He states that an alert newborn may gag and vomit due to vagal stimulation by the process of laryn-goscopy and upper airway suctioning. Additionally, he suggests that positive pressure ventilation via mask and bag may predis-pose to gastric distension, vomiting, and possible aspiration in

infants born through MSAF. Over the past two decades I have attended more than 1000 deliveries of meconium-stained neo-nates. I have never seen meconium aspiration syndrome (MAS) develop as a result of any of these proposed mechanisms.

Dr Katzman is not the first to express concern about the pos-sible aspiration of gastric contents among infants born through MSAF. Karlowicz1_{suggested that these infants could “insidiously} aspirate regurgitated meconium in the first few hours after leaving the delivery room.” Additionally, Karlowicz similarly proposed that the laryngoscopy and intubation procedure could induce regurgitation and aspiration of meconium-stained gastric con-tents. The latter individual suggested routine suctioning of the stomach after 5 minutes of age. He recognized the need for pro-spective, randomized trials to assess the efficacy of such therapy. Both Karlowicz and Katzman expressed particular concern about the thickest consistency MSAF.

I am not aware of any reports in the literature substantiating the aforementioned proposed mechanism of MAS . . . vomiting and aspiration of meconium-stained gastric contents. It is a plausible mechanism unsupported by investigations or anecdotal reports. It would seem reasonable to empty the stomachs of infants born through MSAF. Karlowicz and Katzman differ concerning the timing and manner of such emptying. I am particularly concerned about Dr Katzman’s proposal of applying dorsally directed cricoid pressure. The airway of the neonate is a soft structure with un-derdeveloped cartilaginous support. I would fear damaging the structure. Additionally, I would fear inducing bradycardia in in-fants who already may be depressed. The reports of reflex brady-cardia that Dr Katzman references address nasopharyngeal and tracheal stimulation as the etiology for bradycardia. Orally intro-duced catheters can similarly produce a decrease in heart rate, as any nurse who routinely passes feeding tubes would attest.

The major goal of intubation and intratracheal suctioning of infants born through MSAF is to retrieve as much material as possible from the larger-caliber airways below the vocal cords before it can migrate distally. The act of breathing likely promotes distal migration of meconium-stained fluid. Hence, the recom-mendations that intubation and intratracheal suctioning be per-formed as soon as possible after the neonate is delivered. Until there appears support for the proposed mechanism of MAS (as-piration of regurgitated gastric contents), I do not think tracheal cleansing should be delayed. I certainly recognize that some in-fants may gasp in utero and aspirate MSAF. Additionally, the vast majority of meconium-stained neonates (including those born through thick MSAF) will not develop MAS.

Other preventative measures I have observed among our ob-stetrical colleagues include squeezing the thorax of the infants to prevent deep inspiration and aspiration of meconium-stained flu-ids in the oropharynx and upper airway and inserting one to two fingers deep into the oropharynx purportedly to prevent aspira-tion. Neither of these procedures are supported by scientific data and both are potentially harmful. The potential risks of any pro-cedure must be weighed against the potential benefits. Moreover, proposed treatments must be rigorously studied before their widespread application. I would advocate investigations in ani-mals models before those in human neonates. Primum non nocere.

Thomas E. Wiswell, MD

Division of Neonatology Thomas Jefferson University Philadelphia, PA

REFERENCE

1. Karlowicz MG. More on meconium aspiration. Pediatrics. 1990;86: 1007–1008

Doctors’ vs Parents’ Clinical Assessments: They

Don’t Agree!

To the Editor.—

We feel compelled to respond to the Pediatrics article entitled, “Do Parents and Professionals Agree on the Developmental Status of High-Risk Infants?” by Kim et al because the investigation has methodologic problems and faulty conclusions. We are

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larly keen that parental contribution to the monitoring of their children’s development not be undermined.

We identified three major methodological problems with this study. The first problem relates to the method of completion of the

Infant Monitoring Questionnaire (IMQ) (now revised and called the Ages and Stages Questionnaires). The underlying principle to valid

completion of the IMQ is that parents have adequate time to observe their child across a variety of settings with necessary materials such as blocks and puzzles. It appears from the descrip-tion of procedures that in this study the IMQs were not completed under these conditions and that parents may not have had the opportunity to observe their children over time in the home set-ting. The authors suggest, “Parents are not often reliable in recall-ing historical events in their children’s lives.” Indeed, parents may not have been reliable in this study because of faulty administra-tion procedures necessitating memory of events rather than cur-rent observation.

A second methodologic error pertains to the authors’ scoring of the IMQs, which does not correspond to the scoring procedures recommended and validated by IMQ research studies. Although the IMQs were validated with a two-classification scoring system (pass, fail) using a 2 standard deviation (SD) cut-off point, Kim et al used a three-classification scoring system (pass, fail, suspect). Children were classified as suspect if they had scores between 1 and 2 SDs below the mean on the Bayley; if the infant had abnormalities of tone, posture, and/or reflexes without functional delays; or if a developmental delay of 3 months or less in any of four major areas of development was detected. (It is also unclear to us how a developmental delay of 3 months was determined. If a child showed a 2-month delay, were they still classified as suspect?) When we undertook studies of the validity of the IMQ, children with Bayley scores of 1.5 SD below the mean were clas-sified as abnormal in comparisons with the IMQ. When we inter-preted results by reclassifying suspect scores as normal, sensitivity moved to .72 and specificity to .71.

Related to this study’s scoring classifications is an apparent error pertaining to the interpretation of the logistic regression analyses. The authors state, “There was a statistically significant linear trend (P5.036 byx2_{test for linear trend) with the greatest} agreement when an infant’s status was determined to be normal by the multidisciplinary team” (page 678). A review of the data presented in Table 3 (page 678) shows this to be inaccurate. Instead, the lowest levels of agreement occur when the multidis-ciplinary team classified the infant as suspect (42%), not when the team classified the infant as normal (50%). Indeed, the trend rather than appearing linear, appears nearly curvilinear, with agreement strongest when the team assessed the child as abnormal, lowest when they assessed the child as suspect, and slightly higher again for children assessed by the team as normal. This pattern of data would again seem to indicate that the apparent poor performance of the IMQs is in part a function of using ad hoc categories (ie, suspect). This category was not recommended or ever tested in original psychometric development of the IMQ.

The third methodologic error pertains to the way criterion measures were used in this study. A clinical team assessment was used, consisting of different measures at different ages. There are a number of problems with this design.

First, the criteria changed at differing ages and were adminis-tered by differing professionals each age. For example, the Bayley Mental Developmental Index was administered by a psychologist at 12 months, but not at 4 or 8 months; a motor assessment, the Movement Assessment of Infants, was given by a physical thera-pist at 4 and 8 months but no movement assessment was per-formed at 12 months.

Second, no evidence is given concerning the validity and test-retest reliability of the neurodevelopmental examination per-formed by the developmental pediatricians. How accurate are the “selected items” in identifying infants with atypical and suspect development? Would all pediatricians agree on the identification of a “nice pincer grasp”? Finally, the authors use percentage agreement to indicate the reliability of their own neurodevelop-mental assessment. This seems a puzzling choice as percentage agreement fails to take into account mere chance agreement. Only four paragraphs later in their own manuscript, the authors men-tion the same weakness of percentage agreement and recommend the use of kappa to correct for chance agreement.

Given the problems noted above, the conclusions reached by Kim et al are particularly unsettling. Although the authors note

that “. . . it is still possible that parental assessment is equal to or superior to professional assessment in predicting which children ultimately will have adverse developmental outcomes,” they go on to conclude that clinical judgment be recommended over using the IMQ. Inherent in this recommendation is the underlying premise that when disagreements occurred, the clinical judgment of the professionals was accurate while the parents’ completion of the IMQ was not. Based on the data generated by this study, it is equally valid to conclude that when disagreements occurred, pa-rental completion of the IMQ was accurate while the profession-als’ clinical judgment was not. We are very concerned that the results of this study may be used to argue against the growing recognition of the important role of parents in the assessment and monitoring of their child’s development.

Jane Squires, PhD Diane Bricker, PhD Lawanda Potter, MS Craig Leve, MS

Early Intervention Program University of Oregon Eugene, OR 97403

REFERENCE

1. Kim MM, Steel O’Connor K, McLean J, et al. Do parents and profes-sionals agree on the developmental status of high-risk infants?

Pediat-rics. 1996;97:676 – 681

In Reply.—

We greatly appreciate the letter to the editor by Dr Jane Squires and others in her group. We wish to respond to their concerns regarding our manuscript.

Their first concern pertains to completion of the IMQ in the clinic setting rather than in the home setting. Our study asked parents to complete the questionnaire just before clinical assess-ment, relying to some extent on parents’ recall. This was done to ensure that all parents completed the IMQ in a time frame close to the clinical assessment and also to overcome the problem of those parents who forgot to bring the completed questionnaires. To facilitate the completion of the IMQ, parents were asked to arrive at the clinic 20 to 30 minutes before the clinical assessment, and provided with adequate materials in the waiting room to allow them to observe their children. Thus, we feel that their assessment reflects their infants’ current status.

Their second concern pertains to the scoring of the IMQ. Our group recognizes that the IMQ was validated with a pass-fail scoring system. From a clinical point of view, three categories of clinical classification were felt to be more reasonable as there are a group of infants for whom it is often difficult for clinicians to assign the status “normal” or “abnormal.” This created a need for the “suspect” category. Three categories were created for the IMQ to coincide with the clinical classification system. Furthermore, we felt uncomfortable about accepting the cut-off for our population as the original cut-off for the IMQ was derived from children who were both normal and at-risk.

In a separate analysis, we examined the agreement using the original cut-off and two-way clinical classification (normal versus suspect/abnormal). Kappas were as follows: 4-month 5 0.13, 8-month 5 0.21, 12-month 5 0.29, and combined 5 0.21. An alternative way to classify the infants into two groups clinically would be to use normal/suspect versus abnormal. Kappas under this situation were as follows: 4-month50.17, 8-month50.35, 12-month50.33, and combined50.29. Thus, the use of original cut-off suggested in the manual does not lead to better agreement between the parents and professionals.

Squires et al also commented that there has been an misinter-pretation of the logistic regression analysis. However, they are referring to thex2_{test for trend and they have misinterpreted the} x2_{results. It is true that if one simply plots the % agreement} between parents and professionals for abnormal/suspect/normal status, the results are 72%, 42%, and 50%. However, 42% and 50% are not significantly different, and thex2_{test for trend examines} the three values and determines that the agreement in the “abnor-mal” group is significantly greater.

The third concern pertains to the criterion measure in the study,

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which was the clinical assessment consisting of a developmental pediatrician, physiotherapist, and a psychologist. We agree that the clinical assessment used in this study may not be accepted as the “gold standard” by all professionals. However, this is gener-ally considered realistic and acceptable practice for monitoring development of neonatal intensive care unit graduates in neonatal follow-up programs.

Squires et al criticized the study for having different compo-nents at the assessments at 4, 8, and 12 months. However, we feel this is an accurate reflection of clinical assessments, as the focus of the assessments at different stages of development may differ. We attempted to minimize bias by having the clinical team use the same criteria determined a priori to classify infants into three clinical categories after independent assessments of each infant.

With respect to the framework for the neurodevelopmental examination utilized, the two developmental pediatricians (M.K. and J.M.) involved in this study discussed the importance of the individual items and agreed to look for their presence or absence in determining the status of the infants. The 90% agreement (kap-pa was 0.89, which indicates excellent agreement) suggests that the framework demonstrates good inter-tester reliability for as-sessments at 4, 8, and 12 months. However, it is possible that some pediatricians may not agree on the selected items as being impor-tant or in their interpretation.

We continue to support our conclusion that the IMQ cannot be used as a substitute for clinical assessments of high-risk neonatal intensive care unit graduates in the first year of life. This is not because parental assessments are “inaccurate,” but rather because there is a poor agreement between parental and professional assessments using this questionnaire. We are currently analyzing the ability of parental and professional assessments to predict developmental outcome at 3 years of age. We hope to share this result with the readers of Pediatrics. We share the view held by Dr Squires and others that parental involvement is very important in the developmental assessment and treatment of children.

M. Marie Kim, MD

Department of Pediatrics University of Western Ontario London, Ontario, Canada

Kathleen Steel O’Connor, PhD

KFL & A Health Unit Kingston, Ontario, Canada

Comments on Wilms’ Tumor Experience

To the Editor.—

In the report by Dr Joseph1_{on the section on urology annual} meeting, a summary of the abstract presented by Kessler et al2_on “The Necessity for Contralateral Renal Exploration in Wilms’ Tumor Patients” is presented.

These authors presented their experience with Wilms’ tumor at three separate institutions over an 18-year time period. This paper has recently been published. The findings of their study were that all patients with bilateral Wilms’ tumor were detected preopera-tively. Sixty-eight patients with suspected unilateral Wilms’ tumor underwent exploration by the contralateral kidney explored by opening Gerota’s fascia. They did not find any unexpected bilat-eral tumors. Based on these results, they suggest that the sensitiv-ity of imaging studies in identifying bilateral Wilms’ tumors is “close to 100%.”

We have reviewed the experience with bilateral Wilms’ tumor reported to the National Wilms’ Tumor Study (NWTS)-4 (1986 – 1994).3_{Of 122 patients with synchronous bilateral Wilms’ tumor} enrolled, 7% had the diagnosis of bilaterality missed by the pre-operative imaging studies. With the exception of 1 patient, all of these children had been imaged with either computed tomogra-phy (CT), ultrasound, or magnetic resonance imaging (MRI). Seven of the lesions were missed by preoperative CT. Although this is a small number, it is clear that even with modern imaging studies, small bilateral tumors can be missed preoperatively and therefore the National Wilms’ Tumor Study Group (NWTSG) continues to recommend contralateral exploration. It is important to identify bilateral disease, as the treatment of these children is different from that of unilateral Wilms’ tumor. These patients

undergo preoperative chemotherapy in an attempt to allow for nephron-sparing procedures.

One factor that might explain the apparent increased sensitivity in detection of bilateral tumors in the report by Kessler et al is the limited number of bilateral tumors encountered. There were only 7 patients with bilateral Wilms’ tumor in this series. As noted from the NWTSG review, less than 1 in 10 tumors in the contralateral kidney were missed on the preoperative studies.

The authors have also commented on the decreased rate of small bowel obstruction in patients undergoing preoperative che-motherapy for bilateral tumors. None of the 8 patients with bilat-eral tumors in this series had small bowel obstruction. They noted 5 (7.4%) cases of intestinal obstruction in the patients undergoing treatment for unilateral tumors. In the conclusion of the article, they suggest that avoiding contralateral exploration might miti-gate the high incidence of postoperative intestinal obstruction.

A prior review of surgical complications in NWTSG-3 patients found a 6.9% incidence of postoperative intestinal obstruction. In this group of patients, there were 162 who did not undergo exploration of the contralateral kidney. In that group of patients, the incidence of small bowel obstruction was 5.6% (P 5 NS) (unpublished data). Therefore, omitting exploration of the con-tralateral kidney does not significantly decrease the incidence of intestinal obstruction. An unresolved question is whether the incidence of intestinal obstruction is decreased when nephrectomy is performed after preoperative chemotherapy. A recent report from the International Society of Pediatric Oncology (SIOP) found only a 2% rate of intestinal obstruction in a series of 359 patients.4 The NWTSG and SIOP are conducting a prospective study to compare surgical complications in patients treated by primary nephrectomy versus delayed nephrectomy after chemotherapy.

Michael L. Ritchey, MD Daniel M. Green, MD Norman B. Breslow, PhD Katherine A. Guthrie, BS

University of Texas, Houston Medical School Division of Pediatric Surgery

Houston, TX 77030

REFERENCES

1. Joseph DB. Section on Urology: Report of the Annual Meeting, San Francisco, California, 1995. Pediatrics. 1996;98:108 –114

2. Kessler O, Franco I, Jayabose S, et al. Is contralateral exploration of the kidney necessary in patients with Wilms’ tumor? J Urol. 1996;156: 693– 695

3. Ritchey ML, Green DM, Breslow NB, Moksness J, Norkool. Accuracy of current imaging modalities in the diagnosis of synchronous bilateral Wilms’ tumor: a report from the National Wilms’ Tumor Study Group.

Cancer. 1995;75:600 – 604

4. Godzinski J, Tournade M-F, deKraker J, et al. Surgical complications after postchemotherapy nephrectomy in SIOP-9 Wilms’ tumor patients.

Med Pediatr Oncol. 1994;23:172

An

Asfaliogenic

Complication Arising From

Profit-motivated Decision-making

To the Editor.—

The recent debate over health care reform has focused on ways to allocate care to the greatest number of individuals despite a limited pool of resources. Third-party insurers who pay for pre-scriptions have looked at ways to cut costs, especially for patients with chronic illnesses who may require fairly expensive medica-tions for prolonged periods of time. The substitution of generic products has been an accepted means of reducing cost, yet proof of therapeutic equivalence is required if these products are to be used.1_{We report a case of a 7}1_⁄₂_{-year-old boy with cystic fibrosis} (CF) who developed distal intestinal obstruction syndrome (DIOS) after his health insurance carrier substituted generic for propri-etary pancreatic enzymes despite evidence in the medical litera-ture and expert opinion on their nonequivalence. We propose the term asfaliogenic (Greek–asfalia–insurance) for complications re-sulting from profit-motivated, business decisions by third-party insurance payers.

From birth, our patient was treated with proprietary pancreatic enzyme supplements (Creon, Solvay Pharmaceuticals, Marietta,

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DOI: 10.1542/peds.99.3.501

1997;99;501

Pediatrics

Gerald H. Katzman