ORIGINAL ARTICLES  CARDIAC PAPERS 

The Journal of Cardiovascular Surgery 2001 February;42(1):37-42

Copyright © 2009 EDIZIONI MINERVA MEDICA

lingua: Inglese

Plasma magnesium in patients submitted to cardiac surgery and its influence on perioperative morbidity

Parra L., Fita G., Gomar C., Rovira I., Marín J. L.

From the Department of Anaesthesiology *Department Central Laboratories Hospital Clinic i Provincial University of Barcelona, Barcelona, Spain

Background. To deter­mine the chang­es in mag­ne­sae­mia in car­diac sur­gi­cal ­patients sub­mit­ted to car­di­o­pul­mo­nary ­bypass (CPB) and ­their influ­ence on per­i­op­er­a­tive mor­bid­ity.
Methods. Setting: the car­di­o­vas­cu­lar sur­gery depart­ment of a uni­ver­sity hos­pi­tal. Patients: 60 ­patients of ­both sex­es, ­mean age 60±12 yrs, oper­at­ed on con­sec­u­tive­ly for myo­car­dial revas­cu­lar­iza­tion or ­valve replace­ment. Interventions: plas­ma Mg2+ lev­els ­were meas­ured pre­op­er­a­tive­ly, dur­ing CPB, postCPB and through­out the ­first 24 hrs ­after oper­a­tion. Preoperative plas­ma Mg2+ lev­els of ­these ­patients ­were com­pared ­with ­those of 15 non-car­diac sur­gi­cal ­patients and 11 ­healthy vol­un­teers.
Results. ­Mean val­ues of Mg2+ sim­i­lar in the ­three pop­u­la­tions ­although in the ­group of car­diac ­patients the num­ber of hypo­mag­ne­saem­ic ­patients was sig­nif­i­cant­ly high­er (16 ­patients=26.6%). In ­these 16 ­patients, pre­op­er­a­tive hypo­mag­ne­sae­mia had a sta­tis­ti­cal­ly sig­nif­i­cant rela­tion­ship ­with the pre­op­er­a­tive treat­ment ­with ­beta-block­ers and pre­vi­ous his­to­ry of arrhyth­mi­as (p<0.05). A pro­gres­sive sta­tis­ti­cal­ly sig­nif­i­cant ­decrease of Mg2+ was ­observed through­out the sur­gery ­that ­remained low at 24 ­hours post­op­er­a­tive­ly (p<0.05). Normomagnesemic ­patients need­ed sig­nif­i­cant­ly ­more ­shocks and electri­cal ener­gy to ­obtain ­heart defib­ril­la­tion ­after CPB. The inci­dence of ­both post­op­er­a­tive arrhyth­mi­as and post­op­er­a­tive low car­diac ­index (<2.5 L.m2) was sta­tis­ti­cal­ly sig­nif­i­cant­ly ­more fre­quent in hypo­mag­ne­saem­ic ­patients (p<0.05).
Conclusions. Preoperative hypo­mag­ne­sae­mia was ­more fre­quent in ­this ­small sam­ple of car­diac sur­gi­cal ­patients ­than in non-car­diac sur­gi­cal ­patients and was relat­ed to pre­op­er­a­tive treat­ment ­with ­β-block­ers. Hypomagne-saemia ­caused by CPB per­sist­ed 24 hrs ­after oper­a­tion and was asso­ciat­ed ­with high­er inci­dence of ­both post­op­er­a­tive arrhyth­mi­as and low car­diac ­index.