The effect of high-dose mannitol on serum and urine electrolytes and osmolality in neurosurgical patients

Abstract

The effect of mannitol on serum and urine electrolytes and osmolali~_ was investigated intraoperatively in neurosurgical patients. Patients in Group A (n = 7) received 1 gm,kg -t of 20 per cent mannitol ("low"-dose) Osmotic diuretics are used to reduce intracranial pressure and decrease brain bulk in neurosurgical patients, t'2 lntraoperatively, mannitol is most frequently administered in dose ranges of 0.25-1 gm.kg -I. More recently, high-dose mannitol (2 gm'kg -~) has been shown to have a protective effect in acute focal cerebral ischaemia. 3'4 Accordingly, high-dose maunitol may be given prior to temporary or permanent occlusion of a major cerebral

Comparing Effects of Intraventricular Hypertonic Saline and Magnesium Sulfate Application on Diffuse Brain Injury in Rats

“…Hyperosmolar therapy using mannitol or hyperosmolar saline is a key intervention to overcome cerebral edema. Due to potential complications of mannitol such as intravascular volume depletion, hypotension, and hyperkalemia, hypertonic saline has been increasingly used as a safer alternative to mannitol (11,17,18). However, even though it has safety advantages over mannitol, there is a still controversy on the optimal dose or concentration of hypertonic saline.…”

Could Mannitol-Induced Delay of Anoxic Depolarization be Relevant in Stroke Patients?

“…At the lower end of this range, such an increase would be insufficient (10 mM (Cloyd et al, 1986;Rudehill et al, 1993) ) or perhaps barely sufficient (18 mM (Cloyd et al, 1986)) to afford delay of AD. In the upper end, a 32 mM increase (Manninen et al, 1987) would probably be somehow effective in delaying AD. In fact, we showed that in vitro the addition of 25 mM mannitol (increasing osmolarity by 25 mOsm) significantly delays AD.…”

“…Such a dose leads, still in human patients, to a maximum increase in serum osmolarity of about 10-32 mOsm (Cloyd et al, 1986;Manninen et al, 1987;Rudehill et al, 1993). When experimental animals are considered, administration of 1 g/Kg body weight to rats yelded a serum osmolarity increase of 4 mOsm (Thenuwara et al, 2002).…”

“…Osmotic agent infused Dose Serum osmolarity increase (Cloyd et al, 1986) Humans Mannitol 0.5, 0.7 g/Kg 10 -18 mOsm (Cloyd et al, 1986) Dog Mannitol 0.5, 1, 1.5 g/Kg 43-66 mOsm (Jansson and Rask-Anderson, 1993) Mice Glycerol 1.3, 2.6 and 5.2 g /kg 12-119 mOsm (Manninen et al, 1987) Humans Mannitol 1, 2 g/Kg 32 mOsm (Newman, 1979) Humans Mannitol 2 g/Kg Not reported (Noi and Makimoto, 1998) lower increase of 10 mOsm or less afterwards (Rudehill et al, 1993). Higher doses of mannitol (4 g/Kg and 8 g/Kg, with or without the addition of furosemide) lead, in rats, to a rather high serum osmolarity increase, reaching an average as high as 67 mOsm (Thenuwara et al, 2002).…”

Variation in Osmotic Response to Sustained Mannitol Administration

“…Even in the presence of a disrupted BBB, an osmotic gradient is still established and mannitol is still able to reduce total brain volume (12,13). Hypertonic mannitol solutions rapidly draw water into the extracellular compartment increasing plasma volume (2), which transiently dilutes extracellular sodium (14)(15)(16). In the kidney, mannitol acts as an osmotic diuretic resulting in the excretion of large volumes of free water (2,17).…”