685

CORRESPONDENCE

To the Editor:

It was with interest and concern that I read the paper by Dennis et al. on "The Relationship Between Peak lnspiratory Pressure and Positive End Expiratory Pressure on the Vol- ume of Air Lost Through A Bronchopleural Fistula" (J. Pediatr Surg 15:971-978, 1980). Their conclusion that increasing PIP from 10-30 cm H20 adds little to the air leak from a surgically-created BPF in a rabbit with normal lungs is significant and useful information. However, their unqual- ified statement that " the percentage of inspired volume lost by increasing PEEP from 0-16 cm H20 increases at a rate over six times that seen with increasing PIP" could be misleading to the clinician using this information out of context. This is true only with the experimental conditions that they listed, i.e., by pressure limiting the ventilator to 20 cm PIP for all changes in PEEP settings. The changes in the actual mean volume of air lost through the BPF during the experiment were 4.4 ml (by increasing PIP) and 5.9 ml (by increasing PEEP). Thus, the increase in the percentage of volume lost caused by increasing PEEP occurs predomi- nantly because of the decrease in delivered tidal volume. This latter is caused by using a pressure limiting mode while increasing the PEEP pressure. Therefore, presentation of the data in this form (percentage) is a self-fulfilling prophecy built into the experimental method.

Although it might not have been intended, the title of the paper and the presentation of the data as a percentage of inspired volume imply that these two maneuvers may be comparable or interchangeable for a patient who has a bronchopleural fistula. The two techniques are, of course, different and have different indications. For example, adding PEEP to a pressure limit mode without changing the pressure limit in a patient with a BPF who is hypercarbic would be poor ventilatory management. Of the two maneuvers described, only increasing the PIP can increase the tidal volume (and even this may not reduce the hypercarbia).

The conclusion of Dr. Dennis et al. concerning decreasing PEEP to the lowest possible levels consistent with good oxygenation is appropriate. However, for the physician faced with a hypoxemic patient with a bronchopleural fistula, the data, as presented, does not allow for comparison of these two "ventilatory" maneuvers. PEEP could be indicated to treat the hypoxemia associated with an increased pulmonary shunt. Alternatively, increasing the PIP may also be benefi- cial by decreasing the pulmonary shunt, presumably by increasing the mean airway pressure? Thus, rather than comparing PIP vs. PEEP in units which were arbitrary and not comparable as was done in this study, it may have been more meaningful to compare the leak produced by increasing the PIP vs. the leak produced by increasing the PEEP for the same mean airway pressure. This may then allow the physi- cian who chooses the more conventional means of ventilating a patient with a BPF, (rather than the more recent reported use of High Frequency Positive Pressure Ventilation) 2 a more rational approach in the use of PIP vs. PEEP in an attempt to

treat the hypoxemia. If the authors have that data, the results would be more meaningful for clinical application.

Alan L Fields, M.D., Intensive Care Peter R. Holbrook, M.D., Intensive Care Jennifer K. Light, M.D., Intensive Care Robert Katz, M.D., Intensive Care Children's Hospital National Medical Center 111 Michigan Ave., N.W. Washington, D.C. 20010

REFERENCES

1. Boros S J, et al: The effect of independent variations in inspiratory--expiratory ratio and end expiratory pressure dur- ing mechanical ventilation in hyaline membrane disease: The significance of mean airway pressure. J Pediatr 91:794-798, 1977

2. Carlont GC, Ray C, Klain M, et al: High-frequency positive pressure ventilation in the management of a patient with bronchopleural fistula. Anes 52:160, 1980

To the Editor:

When a colostomy is long established in an infant with rectal atresia or Hirschsprung's disease, subsequent colon anastomosis or pullthrough of bowel segments of greatly disproportionate size results, temporarily at least, in an anastomotic lumen of small caliber. Edema of the bowel at the anastomosis may occlude it further, even totally, for the first few postoperative days. Entrapment of gas between a snug anastomosis and competent ileocecal valve may cause dramatic colonic dilation with painful abdominal swelling, a phenomenon familiar to all pediatric surgeons.

Colonic venting by tube cecostomy performed concur- rently with selected pullthrough procedures and colostomy closures results in a striking absence of postoperative abdomi- nal distention and discomfort.

Scrupulous attention to the following important principles assures effective colonic venting and a low incidence of complications from the cecostomy itself: (1) The colon must be completely cleaned out and decompressed preoperatively. A cecostomy will not function in a stool-packed colon. (2) The tube must be of adequate caliber to permit passage of thick liquid. A large Malecot catheter is preferable to a Foley. (3) The purse string sutures in the cecum should be spaced at least 1 cm apart to create a long serosal tunnel around the catheter. A long serosal tunnel assures prompt closure of the cecal fistula once the tube is pulled. (4) The cecum must be secured to the abdominal wall with seromus- cular-peritoneal sutures placed at 90 ~ intervals around the cecostomy tube.

Although the possible merits of complementary tube cecos- tomy in pediatric surgery are untested, complementary tube

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686 CORRESPONDENCE

gastrostomy, analogous to the former in many ways, has been widely accepted by pediatric surgeons for many years. As is also true for cecostomy, complementary tube gastrostomy does not provide alimentary diversion and does have analo- gous technique-related complications of its own, and yet it has achieved wide acceptance as a vent in pediatric patients undergoing operations on the proximal gastrointestinal tract. Although it does not siphon off all GI secretions, tube gastrostomy does prevent gastrointestinal distention and thereby reduces mechanical stress on proximal anastomoses. A tube cecostomy may offer analogous benefits to the infant or child undergoing post abdominal perineal pullthrough colostomy closure or endorectal pullthrough where tempo- rary postoperative air trapping is likely, yet cecostomy is seldom used by pediatric surgeons as a safety valve in such procedures. My experience suggests that complementary tube cecostomy is a simple, safe procedure that prevents postoperative colon distention following colon surgery in selected pediatric patients. I believe that a wider trial would confirm such a useful role for complementary tube cecostomy in pediatric surgery.

Anthony Shaw, M.D., Director, Department of Pediatric Surgery City of Hope National Medical Center 1500 East Duarte Road Duarte, California 91010

To the Editor:

A recent complication of the needle catheter jejunostomy in a neonate has brought to light several important factors that we feel need to be presented to the surgeons caring for newborns and possibly utilizing this technique. Since pre- viously reporting our experience with this technique, ~ we have additional experience in neonates for a total of approximately 50 neonates undergoing a variety of surgical procedures and having placement of a needle catheter jejunostomy as part of the abdominal procedure. This technique has proven safe in all patients and no catheter related complications have been noted. This has in many instances allowed us to provide long-term nutritional support in patients who would other- wise have to be subjected to total parenteral nutrition.

A recent patient undergoing a needle catheter jejunostomy as a neonate and developing a complication requiring reoper- ation was brought to our attention. This patient had perfora-

tion of the small bowel, distal to the area of placement of the needle catheter jejunostomy apparently from the tip of the catheter eroding through the antimesenteric border of the jejunum. The catheter kit employed was the somewhat rigid catheter manufactured and distributed by Norwich-Eaton Pharmaceuticals. This catheter has been used successfully in many older children and adults; however, it is not the recommended catheter for use in neonates.

The 50 catheters successfully placed in neonates were done utilizing a soft silastic catheter that is available in the needle catheter jejunostomy kit Surgifeed, which is manufactured by HEDECO Corporation in California. It has reportedly been advertised that the Norwich-Eaton jejunostomy kit has been utilized in a large group of neonates. We have not had experience in neonates with this catheter. We have utilized the Surgifeed kit in neonates and the jejunostomy kit distrib- uted by Norwich-Eaton Laboratories for older children and adults. Since the catheter in the Surgifeed kit is a soft silastic catheter, it is the recommended catheter for use in neonates.

We would appreciate any further correspondence from surgeons who have used either of these two kits and have had complications regarding the usage. The Surgifeed kit has presented some problems in older children and adults due to kinking on occasion particularly when the abdominal wall is fairly thick and the catheter is placed into the bowel at an acute angle. The technique of needle catheter jejunostomy and jejunal feeding has proven safe and can be utilized in a large number of patients, providing that the technique is done properly and thecorrect catheter kit is used for the respective age group.

Richard J. Andrassy, LT. COL. USAF, MC Chief, General and Pediatric Surgery Director, Nutritional Support Services USAF Medical Center Keesler/SGHS Keesler AFB, MS 39534

Richard R. Ricketts, M.D. Assistant Professor of Surgery Emory University School of Medicine Atlanta, Georgia

REFERENCE

1. Andrassy R J, Mahour GH, Harrison MR, et al: The role and safety of early postoperative feeding in the pediatric surgical patient. J Pediatr Surg 14:381-385, 1979