The carbon footprint of ambulatory gastrointestinal endoscopy.

BACKGROUND: Endoscopy is considered the third highest generator of waste within healthcare. This is of public importance as approximately 18 million endoscopy procedures are performed yearly in the USA and 2 million in France. However, a precise measure of the carbon footprint of gastrointestinal endoscopy (GIE) is lacking. METHODS: This retrospective study for 2021 was conducted in an ambulatory GIE center in France where 8524 procedures were performed on 6070 patients. The annual carbon footprint of GIE was calculated using "Bilan Carbone" of the French Environment and Energy Management Agency. This multi-criteria method accounts for direct and indirect greenhouse gas (GHG) emissions from energy consumption (gas and electricity), medical gases, medical and non-medical equipment, consumables, freight, travel, and waste. RESULTS: GHG emissions in 2021 were estimated to be 241.4 tonnes CO2 equivalent (CO2e) at the center, giving a carbon footprint for one GIE procedure of 28.4 kg CO2e. The main GHG emission, 45 % of total emissions, was from travel by patients and center staff to and from the center. Other emission sources, in rank order, were medical and non-medical equipment (32 %), energy consumption (12 %), consumables (7 %), waste (3 %), freight (0.4 %), and medical gases (0.005 %). CONCLUSIONS: This is the first multi-criteria analysis assessing the carbon footprint of GIE. It highlights that travel, medical equipment, and energy are major sources of impact, with waste being a minor contributor. This study provides an opportunity to raise awareness among gastroenterologists of the carbon footprint of GIE procedures.

Epileptogenic effect of sevoflurane: determination of the minimal alveolar concentration of sevoflurane associated with major epileptoid signs in children.

BACKGROUND: Sevoflurane has become the gold standard for inhalation induction in children. However in children as in adults, epileptiform electroencephalographic signs have been described under high concentrations of sevoflurane. The aim of this study was to determine the minimal alveolar concentration (MAC) of sevoflurane associated with the occurrence of major epileptiform signs (MES) in 50% children under steady-state conditions. The MAC of MES (MAC MES) was determined in 100% oxygen and with the addition of 50% nitrous oxide or after the injection of alfentanil (ALFENTA). METHODS: Seventy-nine children (3-11 yr), undergoing elective surgery and premedicated with hydroxyzine were included. After induction by inhalation and tracheal intubation, a 10-min period with a stable expired fraction of sevoflurane was obtained. The MES were defined as rhythmic polyspikes or epileptiform discharges. Electroencephalographic recordings were blindly analyzed by two independent experts. The MAC MES were determined by the Dixon method: the concentration of sevoflurane was determined by the result from the previous patient: increase of 0.2% if MES were absent or decrease of 0.2% if MES were present. Three consecutive series were performed: (1) in 100% oxygen (MAC MESO2); (2) in 50% oxygen and 50% nitrous oxide (MAC MESN2O); and (3) in 100% oxygen with a bolus of alfentanil (MAC MESALFENTA). RESULTS: The MAC MESO2 was 4.3±0.1% (mean±SD), the MAC MESN2O and the MAC MESALFENTA were higher, respectively: 4.6±0.2% (P=0.01) and 4.6±0.2% (P=0.02). CONCLUSIONS: In children premedicated with hydroxyzine, the MAC MES of sevoflurane calculated in 100% O2 corresponded to 1.75 surgical MAC. In addition, our results have demonstrated a moderate effect of nitrous oxide and alfentanil in raising the threshold of MES.

Validity of arterialized earlobe blood gases at rest and exercise in normoxia and hypoxia.

The purpose of this study was to compare arterial and arterialized blood gases during normoxic and hypoxic exercise. In the same conditions, earlobe pulse oximetry O(2) saturation (Sp(O2)) was compared to arterial oxygen saturation (Sa(O2)). Ten men performed incremental cycle ergometer tests, in normoxia and hypoxia (FI(O2) = 0.127). Blood samples were drawn simultaneously from the radial artery and pre-warmed earlobe capillary blood of subjects at rest, submaximal and near maximal exercise. R(2) between the two samples were 0.99 for P(O2) and S(O2), 0.86 for P(CO2) and 0.97 between Sp(O2) and Sa(O2). Earlobe P(O2) mean was 4.4+/-3.6 mmHg lower than Pa(O2) in normoxia but in hypoxia only 1.1+/-2.2 mmHg low. The mean difference were low in normoxia between Sa(O2) and Sp(O2) and increased in hypoxia, were acceptable for P(CO2), S(O2), pH in all conditions. In conclusion, except for P(O2) in normoxia, pre-warmed earlobe capillary blood is a good substitute to arterial blood to allow measurement of blood gas values in normoxia and hypoxia at rest and exercise.