From the Guidelines
Normal saline (0.9% sodium chloride) is recommended to increase blood pressure in hypotensive patients, as it expands intravascular volume and increases cardiac output, with a target systolic blood pressure above 90 mm Hg 1. The administration of normal saline can have a significant impact on blood pressure, particularly in patients who are hypovolemic.
- The standard administration rate varies based on clinical need, ranging from maintenance rates of 1-2 mL/kg/hr to bolus infusions of 500-1000 mL over 15-30 minutes for hypotension.
- However, it is essential to monitor patients closely during administration, as excessive or rapid administration can lead to hypernatremia, hyperchloremic metabolic acidosis, and fluid overload, particularly in patients with heart failure, kidney disease, or hypertension.
- A recent study comparing balanced crystalloids versus 0.9% sodium chloride for resuscitation of critically ill adults did not show a significant difference in outcomes 1, but the use of normal saline is still widely accepted as part of an initial restrictive fluid replacement strategy in bleeding trauma patients.
- The choice of crystalloid solution, including normal saline, should be based on the individual patient's needs and underlying conditions, with careful consideration of the potential risks and benefits.
- Clinicians should prioritize monitoring vital signs, urine output, and electrolytes during administration and adjust the rate based on the patient's response and underlying conditions.
From the Research
Effects of Normal Saline on Blood Pressure
- Normal saline is often used as a fluid for resuscitation in hypotensive patients, but its effects on blood pressure are not well understood 2.
- Some studies have investigated the use of hypertonic saline as an alternative to normal saline for treating hypotension, but have found no significant difference in clinical outcomes 3.
- Normal saline is also used as a diluent for medications such as norepinephrine, and its stability and compatibility with these medications have been studied 4.
- In one case report, the use of dextrose 5% in water as a diluent for norepinephrine led to severe hyponatremia and seizure, highlighting the importance of choosing the correct diluent 5.
- The optimal fluid for resuscitation in hypotensive patients remains unknown, and further clinical trials are needed to determine the best approach 2, 3.
Use of Normal Saline in Clinical Practice
- Normal saline is commonly used in clinical practice for fluid resuscitation and as a diluent for medications.
- Its use is often guided by clinical protocols and guidelines, which may vary between institutions and regions 2.
- The choice of normal saline as a diluent for medications such as norepinephrine may depend on factors such as stability and compatibility 4.
- In some cases, alternative fluids such as lactated Ringer's may be used instead of normal saline 2.