Plaintiff underwent surgery for treatment to his shoulder, but suffered an injury to his brain, causing his vegetative state. The brain is not directly or proximately related to the rotator cuff surgery. Therefore, the district court did not abuse its discretion when it submitted a res ipsa loquitur instruction to the jury. Banks v. Sunrise Hospital, 120 Nev. 822, 102 P.3d 52 (2004).

Sunrise had a duty to sequester the anesthesia equipment after victim's cardiac arrest. Evidence concerning Sunrise's duty to preserve the evidence assisted the jury in relation to its prerogative to draw a negative inference from Sunrise's consummated sale of the equipment. Banks v. Sunrise Hospital, 120 Nev. 822, 102 P.3d 52 (2004).

Expert admitted that, under the circumstances, he could not determine whether the equipment contributed to victim's injury since he was unable to examine the equipment because Sunrise had failed to properly identify which machines were used during surgery. Expert's testimony and opinions established that it was possible for the subject equipment to malfunction intermittently. His testimony was also helpful to establish the standard of care for preserving the identity of the machines and providing grounds for the imposition of sanctions for failure to preserve evidence. It assisted the jury in understanding how the machines could have malfunctioned and why it was reasonable to draw an adverse inference from Sunrise's failure to identify the machines. Banks v. Sunrise Hospital, 120 Nev. 822, 102 P.3d 52 (2004).