Spontaneous pneumothorax in the pediatric population

Air in the pleural cavity Lung is partially or completely collapsed Traumatic – usually due to a traumatic defect in the chest wall Spontaneous – unclear etiology – perhaps due to rupture of apical blebs

Treatment: Observation O2 supplementation Chest tube decompression VATS blebectomy and pleuredesis

Incidence – about 0.001% Recurrence – 50-60%

What Factors Predict Recurrence after an Initial Episode of Primary Spontaneous Pneumothorax in Children? Choi et al, Ann Thorac Cardiovasc Surg. 2013

Retrospective review Inclusion: patients 18yo or younger with primary spontaneous pneumothorax Exclusion: surgical intervention, loss to f/u, immediate transfer to outside facility, refusal of CT.

249 cases reviewed 2005-2011 114 included in the analysis Not a very large study, but much better than most for this topic

Rapid growth in adolescence, leading to relatively faster thoracic cavity expansion compared to lung tissue growth? Unclear cause for the above difference in BMI and age.

Definitions of ptx size for that institution (by CXR): Minimal - <1cm Small – 1-2cm Moderate - >2cm, but less than the width of the remaining lung Large – more than the width of the lung Complete – lung tissue in hilum only

Minimall and small (asymptomatic): supplemental O2 Symptomatic and/or moderate and larger: chest tube drainage Air leak 5-7 days – VATS blebectomy and pleuredesis.

What about O2 therapy? Oxygen Therapy for Spontaneous Pneumothorax. Northfield. BMJ, 1971 22 patients with pneumothorax: 12 received rest/observation. 10 had 100% O2 via mask every other day Area of ptx on XR was calculated every day. Tiny study and unclear methods

Resolution of Experimental Pneumothorax in Rabbits by Graded Oxygen Therapy. England et al, J Trauma, 1998. 40 rabbits with surgically created ptx in 4 groups: RA, 30% O2, 40% O2, 50% O2. This was done by injecting air into pleural space

Figure 1 Resolution of Experimental Pneumothorax in Rabbits by Graded Oxygen Therapy. England, Gregory; Hill, Ronald; Timberlake, Gregory; Harrah, Jason; Hill, Jeffrey; Shahan, Yvonne; Billie, Michael Journal of Trauma-Injury Infection & Critical Care. 45(2):333-334, August 1998. Figure 1 . Mean hours to resolution of experimental pneumothoraces in one rabbit in each group of rabbits: room air (21%) and 30, 40, and 50% FiO2. Brackets represent SEM. © Williams & Wilkins 1998. All Rights Reserved. Published by Lippincott Williams & Wilkins, Inc. 2

Supplemental oxygen improves resolution of injury-induced pneumothorax Supplemental oxygen improves resolution of injury-induced pneumothorax. Zierold et al, J Pediatric Surgery, 2000. 27 rabbits with surgically created ptx. This time, this was done with thoracoscopically-guided puncture of visceral pleura. Rabbits divided into 3 groups: RA, 40% O2, 60% O2.

Fig. 1 Time for pneumothorax resolution in the RA, 40%, and 60% groups (data reported as mean ± SD). P <.05 1-way ANOVA RA versus 40%, RA versus 60%, and 40% versus 60%..

Limited studies on O2 therapy. Unclear mechanism – increased partial pressure of O2 in pleural cavity, leading to faster relative absorption?

Presence of radiographic blebs/bullae corresponded to increased risk of recurrence Seems to be in line with blebs/bullae being origins of spontaneous pneumothoraces 86% of patients with bullae on CXR had a recurrence!

Dystrophic severity score? Bleb (<1cm) vs bulla (>1cm): 1 or 2 points One vs many: 1 or 2 points Unilateral vs bilateral: 1 or 2 points

Size of the pneumothorax was not significantly correlated with the chance of recurrence!

Blebs/bullae are correlated with a higher recurrence rate

No relation between blebs/bullae and contralateral recurrence (even with contralateral blebs).

Management of Spontaneous Pneumothorax in Children Seguier-Lipszyc et al, Clinical Pediatrics 50(9) 797– 802, 2011

Retrospective cohort study Included: all patients 18 yo or younger with spontaneous pneumothorax 1999-2009 Excluded: patients with lung disease (except for mild intermittent asthma), malignancy, infection, connective tissue disease, congenital lung disease

46 children were included in the study Patients were offered VATS after 5-7 days of continued air leak or if CT demonstrated blebs/bullae. Patients who did not undergo VATS were offered a CT after the first admission

VATS for the above was performed either during the initial admission or on recurrence with CT showing blebs. The only significant difference between the two groups was the mean length of stay

No difference in recurrence based on CT findings However, the study might be too small to detect differences About a third of the patients did not get a CT scan, making the above conclusion even less clear

No ipsilateral recurrence in patients who underwent VATS!

Primary vs Delayed surgery for Spontaneous Pneumothorax in Children: Which is Better? Qureshi et al, J Pediatric Surgery, 2005. Retrospective review 1991-2003 43 children with spontaneous pneumothorax

Recurrence rate would have to be 72% for the primary surgical treatment to be cost effective (for that particular hospital). Caveat: only one center/one financial system; not current.

Should a CT scan be offered to everyone with a primary spontaneous pneumothorax? Should we continue to administer O2 to asymptomatic patients with small pneumothoraces? Should patients with bullae visible on CXR be offered surgical treatment right away?