Hemodynamic and respiratory changes in surgery of the morbidly obese.

The risk of surgery for the morbidly obese is well known. Suprisingly little information is available regarding the hemodynamic changes during surgery. This study provides data on this important subject and compares them with those of normal nonobese patients. Obese patients demonstrated signifying elevated preoperative, intraoperative, and postoperative right atrial, mean pulmonary artery, and pulmonary artery wedge pressures. Preoperatively, hemodynamic variables were in the high range of normal in obese patients. Significantly greater decreases in cardiac index, right ventricular stroke work (RVSW), and left ventricular stroke work (LVSW) were noticed intraoperatively. Although the RVSW returned to baseline values in the postoperative period, the cardiac index and LVSW remained depressed. Left ventricular function as assessed by Sarnoff curves demonstrated persistent shifts to the right during and after operation. No such shifts were noticed in nonobese patients. Although they were hemodynamically stable and without any other clinical evidence of cardiac abnormality, asymptomatic obese patients had reduced left ventricular contractility (LVSW/pulmonary artery wedge [PAW] pressure ratio) even in the resting state. Obese patients reacted to the stress of surgery and anesthesia by a more specific left ventricular dysfunction that was greater after intubation and in the immediate postoperative period.

Documentation of vasomotor dysfunction by indicator dilution curve analysis.

Indocyanine green dye dilution curves with abnormal contours have been recorded in four patients with acute and critical illnesses using standardized recording methods. The abnormal curves are characterized by a high and prolonged concentration of dye occurring after the peak concentration. This altered contour can be detected by use of routine mathematical processing since the derived hemodynamic parameters are affected by the altered contour. A physiologic basis for the altered curve contour is proposed.

Noninvasive cardiopulmonary monitoring.

Contrast dilution curves have been utilized for evaluation of hemodynamic function. Noninvasive techniques for this purpose usually have been qualitative, expensive, and cumbersome with minimal applicability to the newborn infant. The technique of roentgen densitometry has been utilized to screen children with heart murmurs. Characteristic curve patterns were identified for normal subjects and for patients with shunts with correlation to catheterization data. This technique is now being applied in a quantitative fashion to estimate cardiac output and left-to-right ductal shunts. Cardiac output volumes were inversely proportional to the difference of the second moments of the dilution curves obtained--the second moment being a measurement of the peak dispersion. The estimation of the percent of left-to-right shunt is related to the exponential decay of the left-sided curve.

Monitor-guided responses. Operability with safety is increased in patients with peripheral vascular diseases.

Poor cardiopulmonary reserve was demonstrated in a group of 75 elderly patients undergoing elective vascular reconstruction when cardiovascular hemodynamics were analyzed with the automated physiologic profile (APP) preoperatively. Only 25 patients (33.3%) had normal left ventricular function (LVF) and did not need any corrective therapy before surgery. Increment in preload was necessary in 20 patients (26.7%) to improve myocardial function; 30 patients (40%) revealed abnormal LVF and hence required pharmacologic modulation and preload adjustment, inotropic support, and afterload reduction to enhance the ventricular performance. Conventional methods of clinical evaluation did not reveal the degree of compromised ventricular function and potential high risk of surgical morbidity and mortality in many of these patients. The APP disclosed subtle and important physiologic aberrations indicating modification of anesthetic and operative procedures and precise modulation of physiologic factors. Optimization was achieved in all except two patients, and only one was denied the benefits of vascular reconstruction.

Splenic venous hypertension presenting as variceal hemorrhage caused by portal hypertension.

BACKGROUND: Splenic venous hypertension (SVH) may cause variceal hemorrhage that is clinically indistinguishable from similar bleeding caused by portal hypertension (PH). This may lead to erroneous treatment, including inappropriate portosystemic shunt placement. STUDY DESIGN: A retrospective review of 58 cases of variceal hemorrhage referred for transmesenteric variceal sclerotherapy and transvenous intrahepatic portosystemic shunt (TIPS) placement revealed that seven patients had SVH as a cause of bleeding, and required treatment other than TIPS. The role of medical imaging in the diagnosis and management of SVH was analyzed. RESULTS: Clinical data did not permit a differential diagnosis between PH and SVH as the cause of bleeding in all cases. Splenic venous hypertension was suspected and then confirmed exclusively by contrast-enhanced computed tomography (CT) and angiography, which are essential for correct patient management. CONCLUSIONS: Computed tomography should be routinely performed to exclude SVH before TIPS placement. In instances in which CT fails to establish the diagnosis or splenic artery occlusion is considered for patient management, angiography may be used.

Open chest cardiac massage: an overview.

Open-chest cardiopulmonary resuscitation has been shown to produce better blood flow in man than closed-chest massage. It therefore should be taught as part of the protocol for all hospital CPR teams.

A shunt equation for estimating the splenic component of portal hypertension.

A modification of the Berggren pulmonary shunt equation was derived for use in estimating the splenic component of portal hypertension. It was used in nine patients, six of whom had sufficient decreases in portal flow and pressure after splenic artery and coronary vein ligation. The average decrease in portal flow was 52%.

Preoperative assessment of high-risk surgical patients.

From the foregoing accounts of preoperative assessment of myocardial performance, as well as preload and afterload status it is clear that the proper anesthesia techniques and agents can be selected. Physiologically optimal adjustments of preload, afterload, and myocardial function can be attained by the appropriate, harmonious selection of anesthesia technique and vasoactive drugs made on the basis of close hemodynamic monitoring preoperatively, intraoperatively, and in the immediate postoperative period.

Does pulmonary artery catheter use change outcome? Yes.

This article discusses the advantages of pulmonary artery catheters, with emphasis on the Swan-Ganz catheter. Various studies and published reports confirming the efficacy of pulmonary artery catheter use are reviewed. In the author's opinion, it is evident that the Swan-Ganz catheter has withstood the test of time and scrutiny.

Cytopathology of intra-hepatic bile as component of integrated procedure ("minilap") for hepatobiliary disorders.

Twenty patients with hepatobiliary disorders were prospectively studied by means of minilaparotomy. The study included cytologic evaluation of intra-hepatic bile obtained at trans-hepatic cholangiography. The yield of malignancy identified was increased one third by the cytologic studies.

Assessment of nutritional and metabolic status of paraplegics.

Nutritional and metabolic assessment using anthropometric, biochemical, immunological, and indirect calorimetric techniques was performed on 17 healthy paraplegic males with a mean age of 44.2 +/- 14.6 years and mean duration of injury of 17.8 +/- 12.3 years. Significant differences in energy expenditure were observed; only 29.4 percent were normometabolic [measured resting energy expenditure: (MREE) 90-110 percent of predicted resting energy expenditure (PREE)], 35.3 percent were hypermetabolic (MREE greater than 110 percent of PREE) and 35.3 percent were hypometabolic (MREE less than 90 percent of PREE). Obesity (weight greater than 110 percent ideal body weight) was maximum in hypometabolic patients (83.3 percent) due to the imbalance between caloric intake and energy expenditure (p less than 0.05). None of the patients had normal values for all four objective measurements of nutritional assessment (albumin, transferrin, total lymphocyte count, and cutaneous hypersensitivity). Mild malnutrition was evidenced in 47 percent of patients; 53 percent of patients demonstrated some index of moderate malnutrition. We conclude that nutritional therapy based on measurements of energy expenditure instead of predictive equations will benefit these patients. A larger long-term study is needed to determine the ideal predictive measurements of nutritional assessment with their optimal cutoff values applicable to the spinal cord-injured patient.