Discusión

Hydroelectrolytic disorders following orthognathic surgery

Trastornos hidroelectrolíticos en el postoperatorio de cirugía ortognática

Although fluid losses occurring during the pre- and intraoperative periods are usually corrected, hydroelectrolytic disorders can appear during the postoperative period that are associated with the surgery as well as with an underlying disease in the patient.

Although every patient should be evaluated and treated individually, it is convenient to keep in mind some general guidelines for evaluating the blood volume level in the patient on concluding the surgery: Preoperative fluid levels, losses associated with the surgery, type of fluids and amount administered during its duration, clinical evaluation of the normal blood volume of the patient and an estimation of the fluids retained in traumatized or infected tissues.

"Hydroelectrolytic disorders during the postoperative period following orthognathic surgery" is brilliantly presented in a clear and precise way, and on reading it one is given the possibility of making a series of reflections.

Firstly, as is specifically stated in article, the alterations in osmoregulation during the postoperative period are not exclusive to craniofacial surgery and there is a very limited number of references in the medical literature. However, in this revision these disorders appear with an unusually high frequency. Thus, according to this, 55% of the patients admitted into the Postoperative Resuscitation Unit presented early self-limiting polyuria that was corrected in all cases except one with correct hydroelectrolytic management. This leads us to make a small precision: Perhaps it would be better to refer to "hydroelectrolytic imbalances" (disturbances) rather than "hydroelectrolytic disorders" (a reversal of the normal order).

On the other hand, for a more precise evaluation of the intraoperative situation, which is fundamental for determining how the immediate postoperative [period] evolves, it would have been very interesting to have had a record of the type of mechanical ventilation used during the surgery (we are all familiar with the differences in losses and assistance requirements according to whether open, semi-closed or closed systems are used), the type of fluids administered (crystalloids and/or colloids), and the variations in central venous pressure as well in body temperature.

Finally, I believe it is very important to stress that the majority of the disturbances in osmoregulation that are reported [in this article] are largely specific to a "simple selflimiting polyuria with no hydroelectrolytic disorder". This, in conjunction with the data in the accompanying tables, make one more inclined to think that it is the circumstances regarding the physiological adaptation during the postoperative [period] as opposed to the surgical aggression that this type of surgery entails, that is quite aggressive and requires an anaesthetic technique to match, and the organism to respond to the same extent in order to maintain homeostasis.

This does not mean that there are no clear alterations in osmoregulation observed following certain surgeries, including this [type of] surgery in particular, rather that one should always try to distinguish between these alterations and physiological "disturbances" that are secondary to a considerable surgical and anesthetic aggression to which the organism reacts in the same proportion. Similarly, I believe to be absolutely correct the view of the authors regarding constant observation and a differential diagnosis in order to adopt corrective and/or therapeutic measures promptly according to each case.

The basis of this article is a retrospective study, but given its standard and the importance of the subject raised together with the series of issues presented that remain unanswered, it would be very interesting for further studies of a prospective nature to be carried out.

J. L. Marugán Guijo
Facultativo Especialista de Área.
Servicio de Anestesiología-Reanimación.
Hospital Clínico San Carlos. Madrid. España