Yet humans are rarely attacked by a shark, while millions of sharks are killed by humans. Some populations of shark species, such as the shortspine spurdog, may have dropped by 95 percent. The sharksâ population decline has a ripple effect â throwing entire marine ecosystems out of balance.
Quick Answer. A normal blood oxygen level during sleep is approximately 94 to 98 percent, according to Sleep Apnea Guide. Levels below 90 percent oxygen saturation are dangerous to the human body. The human brain can only survive four minutes without oxygen before cell death occurs.
After toileting, the client returns to bed and his oxygen saturation is measured at 82%. The hemoglobin of 6 gm/dl (normal is 14 to 18 gm/dl in males) and the 82% O2 saturation (normal is 96 to 100%) indicates the client is hypoxic, so the first transfusion of blood should be started (B).