[Intraoperative measurement of cardiac output by transesophageal echocardiography of transmitral flow]. / Medición de gasto cardíaco a nivel de válvula mitral con ecocardiografía transesofágica intraoperatoria.

INTRODUCTION: Intraoperative transesophageal echocardiography is used to study cardiac structure and function. Cardiac output is measured by calculating the velocity with which a volume of blood travels a predetermined area. Output can be assessed at the mitral valve by parallel alignment of the Doppler transducer to measure flow velocity. OBJECTIVE: To compare cardiac output measurements from transesophageal echocardiography with measurements performed by the standard clinical technique of thermodilution. PATIENTS AND METHODS: Cardiac output measurements obtained by thermodilution and by echocardiography at the mitral valve were compared in a prospective study during 34 cardiac surgery procedures. RESULTS: Cardiac output measurements ranged from 2.3 L min(-1) to 7.8 L min(-1) (mean 4.27 +/- 0.125 L min(-1) for measurements made by Doppler echocardiography and from 1.9 L min(-1) to 8.1 L min(-1) (mean 4.36 +/- 0.124 L min(-1)) for measurements made by thermodilution. The correlation between the methods was high (r = 0.926, p = 0.00001). CONCLUSION: Intraoperative measurement of cardiac output by transesophageal Doppler echocardiography at the mitral valve is easy and correlates highly with the clinical method of thermodilution used at present. Use of the technique will widen the spectrum of information provided by echocardiography, which is a safe, minimally invasive technique.

A safe model for creating blunt and penetrating ballistic injury.

Minor modification of an existing readily available captive projectile weapon system has allowed development of a safe model for studying both penetrating ballistic and blunt tissue injury. A captive projectile weapon (defined as a firearm in which the projectile does not leave the weapon and in which the external wounding range is very limited) diminishes greatly the possibility of injury to personnel while it allows a high degree of reproducibility. The system has three parts: the pistol (wt 1.3 kg), a stainless steel stand, and a rack for holding the organ to be injured. It has been used 14 times in developing a canine model for the study of penetrating ballistic renal injury. When a 2 grain, .22 caliber charge is fired in the weapon, the .45 caliber captive projectile travels 7.5 cm and penetrates the kidney completely. The kinetic energy available for transfer from the projectile to the kidney and renal vessels totals 211 joules, which is comparable to the kinetic energy of projectiles for many law enforcement sidearms at 45.72 meters (50 yards) from the muzzle of the weapon. Comparison of the wounds showed complete reproducibility of injury (100%) over all 14 subjects [Entrance wound greater than or equal to .45 caliber (100%). Exit wound greater than or equal to .45 caliber (100%). Complete penetration (100%)]. This weapon system can be modified to duplicate the injury created by missiles from many small arms by modifying the captive projectile and/or the charge. Changing the leading surface of the captive projectile allows delivery of the energy over a broad surface such that blunt injuries can be simulated.

Bone marrow acid phosphatase by radioimmunoassay: 3 years of experience.

Clinical followup of 112 patients staged by the immunochemical determination of prostatic acid phosphatase from bone marrow aspirates is presented. This represents a 94 per cent (112 of 118) retrieval rate of a group studied more than 2 years previously. Of the 11 patients judged to be at high risk 4 (36 per cent) have suffered bony metastases, whereas only 3 of 86 patients (3 per cent) with normal bone marrow acid phosphatase by radioimmunoassay have done so. An additional 184 patients with carcinoma and 77 controls have been studied. Although radioimmunoassay greatly improves specificity in bone marrow aspirates a few falsely positive results can occur. This finding may be secondary to cross reaction from leukocyte acid phosphatase and/or interference from lipid.