U.S. hospital intensive care units in many parts of the country are straining under record numbers of COVID-19 patients. These hospital units take care of the sickest of the sick. Some are running out of space and supplies, while scrambling to pay the soaring rates of temporary traveling nurses. Hundreds of ICUs are struggling at the same time, with many clustered in the South and West. An Associated Press analysis shows that since November, the share of U.S. hospitals nearing the breaking point has doubled. More than 40% of Americans live in areas running out of ICU beds. Experts say sustained surges can jeopardize the quality of care in ICUs.