What type of fluids are used for resuscitation in hypovolemic shock?

• A. Isotonic solutions such as normal saline and lactated Ringer's
• B. Hypotonic solutions
• C. Hypertonic solutions
• D. Colloids only

Answer: (A)

The goal in resuscitating hypovolemic shock is to rapidly restore intravascular volume with fluids that stay in the vascular space to increase preload and cardiac output. Isotonic crystalloids, like normal saline and lactated Ringer’s, have osmolality close to plasma, so they remain mainly in the extracellular and intravascular compartments after administration. This effectively expands circulating volume without causing significant shifts of water into or out of cells, which helps raise blood pressure and improve perfusion quickly.

Hypotonic solutions would pull water into cells, worsening hypotension and tissue edema. Hypertonic solutions can draw water from cells into the vasculature but cause rapid and sometimes dangerous shifts, requiring careful monitoring and aren’t the standard first-line choice for uncomplicated hypovolemic shock. Colloids, while they can be used in certain contexts, are not the default sole fluid for resuscitation; isotonic crystalloids are the typical initial resuscitation fluid.