Technical and pharmacologic management of distal hypotension during repair of coarctation of the aorta.

Neurologic and abdominal complications can occur in the postoperative period of aortic coarctation repair, ischemia being the pathogenic factor most likely to be involved. This study was designed to evaluate the extent of the hemodynamic changes proximal and distal to the coarctation at the time of cross-clamping, as well as the effects of pentolinium and isoproterenol upon the hemodynamic changes. Included in the study were 17 patients with adult type coarctations who had dual hemodynamic monitoring. During cross-clamping, there was an increase in the gradient between proximal and distal pressures, with severe distal hypotension (< 50 mm Hg) occurring in six patients. Isoproterenol corrected the hypotension in five patients, but the sixth required a surgical shunt. Pentolinium was effective for the treatment of proximal hypertension; however, it also decreased distal pressure. The ligation of collateral vessels was associated with a decrease in distal pressures as well. During cross-clamping, pentolinium was useful for the management of proximal hypertension and isoproterenol increased the distal pressures in some of the patients who presented distal hypotension. However, because of the difficulties in predicting the individual response, their administration would be best guided by dual pressure monitoring. It is postulated that the recognition and proper treatment of distal hypotension may be an important factor in the prophylaxis of postoperative complications.

The anesthetic management of the severely burned patient.

The anesthetic management of patients with major burns must be based on pathophysiological knowledge of the disease. In the immediate post-burn period hemodynamic changes are of major importance. Because in severe cases any of the determinants of cardiac output can be implicated in these changes, precise physiological measurements are required. Arterial pressure, urinary output, central venous pressure and right heart catheterization can help in choosing the appropriate intervention. The metabolic response to the injury is initially protective, providing enough substrate, but later will lead to extreme levels of catabolism which can impair wound healing and immunological response. The anesthesiologist can decrease that response by providing calories, adequate room temperature, a reduction of the NPO period to the minimum necessary, and avoiding stress situations. Respiratory injury can either affect the upper airway or produce the picture of ARF, which may require special treatment before, during and after surgery. Several technical problems are usually present in the anesthetic management of these patients: 1) difficult airway, 2) scarce venous access, 3) no places available for monitoring, 4) drug dependency, 5) multiple anesthetics, 6) tendency to hypothermia, 7) inaccurate estimation of blood loss, 8) hyperkalemia after succinylcholine administration, and 9) systemic effect of topical medications.

The effect of short-term discontinuation of high-level PEEP in patients with acute respiratory failure.

PEEP is the most important therapeutic intervention in the management of acute respiratory failure. Transitory PEEP disconnection to perform clinically relevant maneuvers is often necessary, but its effect upon PaO2 and physiological shunt in patients requiring high-level PEEP is not clear from the literature. Nine adult patients in severe respiratory failure requiring high-level PEEP therapy were studied. The elimination of PEEP decreased the PaO2 and increased the physiological shunt. Maximum values were reached in about 4 min. Restoration of PEEP after 7.4 min in zero and end-expiratory pressure caused an increase in the PaO2 and decrease in the physiological shunt. Baseline values were restored in about 5 min. In 4 patients having endotracheal suction under hand ventilation with 100% oxygen, the continuous PaO2 recording showed an increase in PaO2 during the maneuver. Therefore, necessary manipulations can be accomplished without fear of negating the salutory effects gained by high-level PEEP therapy.

Large-volume liposuction in 181 patients.

Liposuction is a commonly performed cosmetic surgery procedure that is associated with complications, including fatalities. Many of these have been associated with large-volume liposuction. During 1998 the American Society of Plastic Surgery Task Force on Lipoplasty and the Plastic/Cosmetic Surgery Committee of the Medical Board of California have both arbitrarily defined large-volume liposuction as greater than 5000 cc and asked that surgeons not remove any more than this volume except in specific circumstances such as a hospital-type setting [1]. This study includes 181 patients who have had greater than this amount of total aspirate removed in a single procedure. From January 1, 1996, to February 11, 1997, we used tumescent liposuction only (31 patients). From February 12, 1997, to June 30, 1998, we used a combination of ultrasonic liposuction using the Lysonix 2000 Ultrasonic Liposuction Unit and tumescent liposuction (150 patients). During the last part of the latter series we calculated the blood loss of 45 patients derived from preop and 5-day postop hematocrits. The results show that (1) there is no correlation between the aspirate volume and the calculated blood loss; (2) the majority of the calculated blood loss is not in the cannister; and (3) no deaths occurred, but one patient suffered a deep venous thrombosis and two patients suffered pulmonary emboli. As others have pointed out [2-6] large-volume liposuction can be performed relatively safely if this procedure is treated with the respect it deserves and the practitioner exercises sound surgical judgment, uses appropriate technique, and does not try to cut corners to save money for the patient by performing this surgery in minimal settings.

Lumbar epidural anaesthesia and sensory profiles in term pregnant patients.

Sensory profiles of lumbar epidural anaesthesia were studied in 57 patients, during active labour. The local anaesthetics used were chloroprocaine three per cent with and without epinephrine, chloroprocaine two per cent, bupivacaine 0.25 per cent and a mixture of chloroprocaine three per cent and bupivacaine 0.5 per cent. A common pattern of spread was found for all local anaesthetic solutions with the onset of the block affecting the dermatomes innervated by the thinnest nerve roots (T12L1). There was a percentage of failure to block the thickest nerve root (S1). Inguinal and suprapubic discomfort ("missing segment") occurred when S1 was not blocked. Under the conditions of this experiment, the addition of bupivacaine to chloroprocaine did not increase the duration of the blockade significantly.