By Margaryta Chornokondratenko OBUKHIV, Ukraine (Reuters) – Each time Ukrainian pensioner Halyna Halytska prepares for her hospital treatment, she is preoccupied with a single thought: Will there be enough power and water to see her through? Outages, caused by Russian air strikes on Ukraine’s infrastructure, can last for hours at a time as Halytska and 27 other patients lie tied to their dialysis machines in hospital in Obukhiv, a city south of Kyiv. The power cuts hit pumping stations – a particular worry for the patients whose treatments use hundreds of litres of running water. Medics do the…