BACKGROUND: Moderate sedation for gastrointestinal endoscopy has traditionally been provided by the endoscopist. Controversy has ensued over safe and efficient sedation practice as endoscopy has increased in numbers and complexity.

AIM: To evaluate the safety of ketamine sedation given by non-anesthesiologist during gastrointestinal endoscopy in children.

METHODS: A prospective study of 100 paediatric patients with gastrointestinal symptoms who were a candidate for upper or lower gastrointestinal endoscopy in paediatric endoscopy unit at Abo El-Reesh Paediatric Hospital, Cairo University. All children were > 2 years old and weighed > 6 kg. The analysis was performed in terms of sedation-related complications.

RESULTS: A total 100 paediatric patients including 53 males and 47 females with mean age of 5.04 years were involved in the study. All children were medicated with ketamine with a mean dose of 3.77mg/kg. No complications occurred in 87% of cases. Desaturation occurred in 13% of the cases and was reversible by supplemental nasal oxygen. Desaturation was more frequent during Upper GI Endoscopy and with the intramuscular route (p value=0.049). No apnea, bradycardia, arrest or emergence reactions were recorded.

CONCLUSION: Ketamine sedation found to be safe for paediatric gastrointestinal endoscopy in Egyptian children without co-morbidities. Transient Hypoxia (13%) may occur but easily reversed by nasal oxygen therapy.

It was claimed in a recent publication that a strain of Halomonadacea bacteria (GFAJ-1) isolated from the arsenic-rich waters of Mono Lake, California is able to substitute arsenic for phosphorus in its macromolecules and small molecule metabolites. In this short Perspective, we consider chemical and biochemical issues surrounding the central claim that Halomonadacea GFAJ-1 is able to survive while incorporating kinetically labile arsenodiester linkages into the backbone of its DNA. Chemical precedents suggest that arsenodiester linkages in the putative arsenic-containing DNA of GFAJ-1 would undergo very rapid hydrolytic cleavage in water at 25 °C with an estimated half-life of 0.06 s. In contrast, the phosphodiester linkages of native DNA undergo spontaneous hydrolysis with a half-life of approximately 30,000,000 y at 25 °C. Overcoming such dramatic kinetic instability in its genetic material would present serious challenges to Halomonadacea GFAJ-1.