The management of acute shortness of breath in young adults.

Shortness of breath (SOB), or dyspnoea, is a common presenting symptom in acute care, responsible for 8% of all 999 calls to the ambulance service and ranking as the third most common type of emergency call-(l). It may be associated with significant pathology, so prompt identification and appropriate management are therefore imperative. Although a formal diagnosis guides risk stratification, prognostication and treatment, it must not delay resuscitation. Rather, the management of an acutely short of breath (ASOB) patient must follow an algorithm incorporating simultaneous assessment and resuscitation. This article discusses both of these aspects in some detail, as well as key features in the history and the differential diagnosis, before concluding with some consideration of how the different operational environments in which such patients can present may affect their management.

Closed and open breathing circuit function in healthy volunteers during exercise at Mount Everest base camp (5300 m).

We present a randomised, controlled, crossover trial of the Caudwell Xtreme Everest (CXE) closed circuit breathing system vs an open circuit and ambient air control in six healthy, hypoxic volunteers at rest and exercise at Everest Base Camp, at 5300 m. Compared with control, arterial oxygen saturations were improved at rest with both circuits. There was no difference in the magnitude of this improvement as both circuits restored median (IQR [range]) saturation from 75%, (69.5-78.9 [68-80]%) to > 99.8% (p = 0.028). During exercise, the CXE closed circuit improved median (IQR [range]) saturation from a baseline of 70.8% (63.8-74.5 [57-76]%) to 98.8% (96.5-100 [95-100]%) vs the open circuit improvement to 87.5%, (84.1-88.6 [82-89]%; p = 0.028). These data demonstrate the inverse relationship between supply and demand with open circuits and suggest that ambulatory closed circuits may offer twin advantages of supplying higher inspired oxygen concentrations and/or economy of gas use for exercising hypoxic adults.