The

n e w e ng l a n d j o u r na l

of

m e dic i n e

1. Abroug F, Ouanes-Besbes L, Ouanes I, et al. Meta-analysis of

Geoffrey K. Isbister, M.B., B.S., M.D.

controlled studies on immunotherapy in severe scorpion envenomation. Emerg Med J 2011;28:963-9. 2. Armstrong EP, Bakall M, Skrepnek GH, Boyer LV. Is scorpion antivenom cost-effective as marketed in the United States? Toxicon 2013;76:394-8. 3. Isbister GK. Antivenom efficacy or effectiveness: the Australian experience. Toxicology 2010;268:148-54. 4. Stone SF, Isbister GK, Shahmy S, et al. Immune response to snake envenoming and treatment with antivenom: complement activation, cytokine production and mast cell degranulation. PLoS Negl Trop Dis 2013;7(7):e2326. 5. Brown SG, Stone SF, Fatovich DM, et al. Anaphylaxis: clinical patterns, mediator release, and severity. J Allergy Clin Immunol 2013;132(5):1141.e5-1149.e5.

University of Newcastle Newcastle, NSW, Australia [email protected]

Himmatrao S. Bawaskar, M.B., B.S., M.D. Bawaskar Hospital and Research Centre Mahad, Dist-Raigad, Maharashtra, India

Simon G.A. Brown, M.B., B.S., Ph.D. University of Western Australia Perth, WA, Australia Dr. Brown reports no potential conflict of interest relevant to this letter. Since publication of their article, Drs. Isbister and Bawaskar report no further potential conflict of interest.

DOI: 10.1056/NEJMc1410354

Oxygen Desaturation in Infants during Aeromedical Transport To the Editor: Scant data have been published on the oxygenation and safety measures required for the aeromedical transport of infants. Current guidelines recommend avoidance of air travel for infants younger than 1 week of age and avoidance of ascent to moderate (2500 m) to high

(≥2500 m) altitude until 6 weeks of age in healthy full-term infants.1,2 In situ flight research shows that there is an increased risk of hypoxemia in preterm infants and in those with respiratory disease, but not in healthy full-term infants who are older than 6 months of age.3-5 We report the

Table 1. Infant Spo2 According to Age and Type of Aircraft.* Means of Transport and Infant Age

No. of Infants

No. of Infants with Desaturation Spo2 37 wk, or ≤1 wk

17

4/17 (24)

95 (88–100)

>1 wk–6 wk

7

3/7 (43)

94 (84–100)

>6 wk–3 mo

3

0

97 (96–98)

>3 mo–6 mo

6

0

98 (96–100)

Rotary-wing aircraft Postmenstrual age ≤37 wk

12

5/12 (42)

94 (73–98)

Postmenstrual age >37 wk, or ≤1 wk

29

13/29 (45)

94 (83–100)

>1 wk–6 wk

11

2/11 (18)

95 (87–100)

>6 wk–3 mo

8

3/8 (38)

96.5 (45–100)

>3 mo–6 mo

6

2/6 (33)

97.5 (86–100) 94.5 (60–98)

Fixed-wing and rotary-wing aircraft Postmenstrual age ≤37 wk

25

9/25 (36)

Postmenstrual age >37 wk, or ≤1 wk

46

15/46 (33)

95 (83–100)

>1 wk–6 wk

18

8/18 (44)

95 (83–100)

>6 wk–3 mo

11

2/11 (18)

97 (45–100)

>3 mo–6 mo

12

2/12 (17)

98 (96–100)

* Postmenstrual age is defined as gestational age plus chronological age (time elapsed from birth).

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correspondence

findings of a study examining the effect of hypobaric hypoxia during aeromedical transport in infants younger than 6 months of age. Oxygen saturation in infants less than 6 months of age was measured by means of continuous pulse oximetry (Spo2) during aeromedical transport from January 2010 through December 2011 to define the incidence of desaturation (defined as Spo2