PubMed1972
In response to a question on how to avoid the rare, inadvertent intravascular or ip injection of hypertonic saline solution during therapeutic abortion, 3 consultants replied. According to Reid and Frigoletto, to avoid intravascular or ip infusion, place a small indwelling polyethylene catheter in the amniotic sac rather than a metal needle. This virtually precludes the possibility of inadvertent iv injection. When and if necessary, correct catheter placement may be confirmed by the use of fluoroscopy and amniography prior to the injection of hypertonic saline solution. The chemical imbalances associated with this accident are those encountered in severe hypernatremia with resultant brain edema and hemorrhagic softening. Bizarre paresthesia, pyrexia, altered consciousness, and, eventually, convulsions preceded the fatal cases. Peritoneal dialysis may be life saving in the event of ip injection. Naturiuretics, appropriate parenteral fluid administration, and possibly exchange transfusion might be indicated for intravascular accidents. In Goodlin's hospital there have been no cases of acute hypernatremia in the last 500 therapeutic abortions done with hypertonic saline solution. This is believed to be related to 2 changes in technique: 1) not losing the amniotic space by removing only as much amniotic fluid as can easily be obtained and 2) using a simple gravity infusion technique for the instillation of the hypertonic saline solution. During infusion it is essential that the patient be alert, for the first symptoms of intravascular injection are a slight pain, burning, or a feeling of warmth in the pelvis. If these minor symptoms are ignored and the procedure is continued, a sensation of flushing occurs throughout the body with tingling in the scalp and ringing in the ears followed finally by seizures, apnea, or coma or both. Late symptoms are those of hemolytic anemia and renal failure. From experience, serum sodium levels during these events are as high as 185 mEq/1. Along with occurrence of acute hypernatremia the contents of the amniotic cavity are sometimes extruded extraovularly through the fallopian tube into the peritoneal cavity when labor begins. Cases with serum sodium levels of 170 mEq/1 some 6-7 hours after saline instillation were observed, but by contrast these patients' only symptoms were extreme thirst and peritoneal discomfort (Lancet 1: 305, 1968). The treatment of hypernatremia is to force fluids either by mouth or iv. Since most commercial 5% dextrose in water solutions are actually 4.5% (regulations permit a 10% error), such hypotonic fluids are useful for treating hypernatremia.