CARDIAC RATIONALES: Hypovolemic shock most commonly occurs from blood loss but can occur in any condition that reduces intravascular volume. Hypovolemia is classified as either an absolute (ex. hemorrhage, surgery, gastrointestinal bleeding, vomiting, diarrhea) or a relative (ex. pancreatitis, sepsis) fluid loss. Reduced intravascular volume results in decreased venous return, decreased stroke volume and cardiac output, inadequate tissue perfusion, and impaired cellular metabolism. Clinical manifestations of hypovolemic shock are associated with inadequate tissue perfusion and include: • Change in mental status • Tachycardia with thready pulse • Cool, clammy skin • Oliguria • Tachypnea Decreased urine output (<0>100 seconds would be considered critical and could result in lifethreatening side effects. Common sentinel events that result from heparin drips include epistaxis, hematuria, and gastrointestinal bleeds. A normal hematocrit for a female is 35%-47% (0.35-0.47). In a client with a history of chronic anemia, a hematocrit of 30% (0.30) may be an expected finding. A normal platelet count is 150,000-400,000/mm3 (150-400 x 109 /L). In a client with a history of liver cirrhosis, a platelet count of 80,000/mm3 (80 x 109 /L) would be anticipated. An episode of bleeding rarely occurs with a platelet count >50,000 mm3 (50 x 109 /L). A normal prothrombin time is 11-16 seconds, and so a level of 11 seconds would not be concerning. Heparin infusions require close monitoring by the nurse. The partial thromboplastin time is the laboratory value required to accurately monitor the therapeutic effects of heparin. 2 Ventricular paced rhythms are seen in clients with ventricular pacemakers. Ventricular pacemakers typically have one lead placed in the right ventricle. The pacer spike just before the QRS complex signals electrical stimulation of the ventricle by the pacemaker lead (Option 3). The pacemaker lead depolarizes the right ventricle first, and electricity travels across the heart to depolarize the left ventricle. This atypical electrical pathway distorts and widens the QRS complex. The T wave can be seen immediately after the wide QRS complex. Implanted permanent pacemakers are often placed in clients with symptomatic bradycardia or heart block. Demand pacemakers are the most common type of implanted permanent pacemaker. The demand pacemaker sends an electrical impulse (pacer spike) only if the pacemaker does not sense an intrinsic heartbeat occurring at the programmed threshold rate (eg, 40/min). Ventricular paced rhythms have a pacerspike just before the QRS complex, which is usually distorted and wide. Implanted permanent pacemakers are often placed in clients with symptomatic bradycardia or heart block. Electrical cardioversion is a treatment modality considered for A. Fib that has been unresponsive to drug therapy. A Fib (rapid, irregular atrial contractions) results in ineffective atrial kick and predisposes to thrombus formation (blood clots) in the left atrium. If a client is in A. Fib for more than 48 hours, anticoagulation therapy is needed for 3-4 weeks before cardioversion. Anticoagulation therapy is necessary as cardioversion may dislodge an atrial thrombus, putting the client at risk for a stroke or other sequelae of thromboembolism. If 4 weeks of anticoagulation is not an option, TEE must be performed prior to cardioversion. A TEE (Transesophageal Echocardiogram) isindicated prior to cardioversion for a client who has been in AF for more than 48 hours, as cardioversion is contraindicated in the presence of an atrial thrombus.