The Science Journal of the American Association for Respiratory Care
A case of hypovolemia, decreased cardiac output, and diminished pulmonary capillary blood flow reflected through monitoring volumetric CO2[CO2 production (VCO2) and deadspace (Vd/Vt)].
A ninety year old female patient admitted for bursitis of the shoulder was diagnosed with coronary artery occlusion resulting in angina.
Worked up for coronary artery bypass graft (CABG) surgery, prepped in the preanesthesia laboratory the patient was assessed and followed during surgery as well as postoperatively in the intensive care unit (ICU).
After the patient was intubated the Novametrix, CO2SMO PLUS Respiratory Profile Monitor was placed common to inspiration and expiration and anesthesia induction continued. Respiratory parameters were continuously monitored and trended, see graft below. Volumetric CO2 (VCO2) diminished progressively as Positive Pressure Ventilation (PPV) was initiated and throughout the entire case, as the patient was not placed on cardiopulmonary bypass. Periods of hand bagging off the ventilator led to even lower VCO2 with increased deadspace (Vd/Vt). During the following 12 hours postoperative recovery in the ICU, hypertension, agitation and adequate pain management hampered liberation from the ventilator. Cardiac output (CO) was 3.8L/M and VCO2 was 50ml/min. Fluid resuscitation was not considered an option as the patients left ventricular ejection fraction was < 50%. The patient was challenged to breathe spontaneously on continuous positive airway pressure (CPAP). VCO2 steadily increased, rapid shallow breathing index (f/Vt) was <100. The patient was successfully liberated and extubated without any sequelae. It appears that monitoring VCO2 can empower the RCP to safely and correctly adjust and fine tune weaning strategy, limit blood gas usage and possibly decrease mechanical ventilation time.
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