Hydroxocobalamin to treat refractory vasoplegia following phaeochromocytoma resection in a child.

Phaeochromocytomas and paragangliomas are rare neuroendocrine tumours that often secrete catecholamines, which can cause dramatic swings in blood pressure and end-organ damage. During surgical resection of these tumours, antihypertensive drug infusions are often required, but after resection patients may become vasoplegic, in part due to cessation of catecholamine secretion by the tumour in the context of pre-operative α1 adrenoceptor antagonism. Numerous medications have been used to treat vasoplegia in this setting, including noradrenaline, vasopressin and, more recently, angiotensin II. We report the case of a patient who experienced vasoplegia after phaeochromocytoma resection which was refractory to vasopressin and angiotensin II infusions but was successfully treated with high dose hydroxocobalamin.

Determination of the site of tracheal tube impingement during nasotracheal fibreoptic intubation.

This study examines the incidence and site of tracheal tube impingement during nasotracheal fibreoptic intubation, and the efficacy of anticlockwise tube rotation to overcome the problem. Forty-three patients underwent fibreoptic-assisted nasotracheal intubation using a preformed nasal tube, and a second fibrescope was used to observe any obstruction to passage of the tracheal tube. Impingement occurred in 10 cases, with the most common site being the right arytenoid cartilage. Rotation resulted in successful intubation in all 10 cases, but proximal rotation did not always result in an equal degree of rotation at the tube tip. We conclude that the site of impingement for nasotracheal intubation with preformed nasal tubes is located at the posterior structures of the laryngeal inlet and that anticlockwise rotation is a simple and effective solution.

Measurement of cardiac output by transpulmonary arterial thermodilution using a long radial artery catheter. A comparison with intermittent pulmonary artery thermodilution.

Cardiac output can be measured accurately by transpulmonary arterial thermodilution using the PiCCO (Pulsion Medical Systems, Munich, Germany) system with a femoral artery catheter. We have investigated the accuracy of a new 50 cm 4 French gauge radial artery catheter and the ability to use the system with a shorter radial catheter. We studied 18 patients who had undergone coronary artery surgery and made three simultaneous measurements of cardiac output by arterial thermodilution and with a pulmonary artery catheter. The radial catheter was withdrawn in 5 cm increments and the measurements were repeated. We found close agreement between arterial thermodilution and pulmonary artery thermodilution with a mean (SD) bias of 0.38 (0.77) l x min(-1). Arterial thermodilution became unreliable once the catheter had been withdrawn by more than 5 cm. We conclude that cardiac output measurement with arterial thermodilution with a radial catheter is interchangeable with that derived from a pulmonary artery catheter, and that a centrally sited arterial catheter is required for accurate determination of cardiac output by transpulmonary arterial thermodilution.

Laparoscopic management of bladder pheochromocytoma.

Pheochromocytoma primarily involving the bladder is an uncommon pathologic finding. Patients may present with transient hypertension associated with palpitations and diaphoresis on micturition. A case of bladder pheochromocytoma treated by laparoscopic partial cystectomy is presented. The management principles of bladder pheochromocytoma for our specific case are discussed. Successful treatment requires that the correct diagnosis and tumor location be made in conjunction with the obligatory preoperative preparation of the patient.

A multicenter evaluation of a new continuous cardiac output pulmonary artery catheter system.

OBJECTIVE: To validate a new system of continuous cardiac output monitoring. DESIGN: Multicenter, prospective, nonrandomized clinical study. SETTING: Four university hospitals. PATIENTS: Forty-seven adult intensive care unit patients. INTERVENTIONS: Pulmonary artery catheterization. MEASUREMENTS AND MAIN RESULTS: Continuous and bolus cardiac output measurements were obtained over 72 hrs. The 327 continuous cardiac output measurements compared favorably with bolus cardiac output measurements (bias = 0.12 L/min, precision = +/-0.84). The continuous cardiac measurement was not adversely affected by temperatures of <37 degrees C or >38 degrees C, high (>7.5 L/min) or low (<4.5 L/min) cardiac output values, or duration (72 hrs) of the study. CONCLUSIONS: This continuous cardiac output system provides a reliable estimate of cardiac output for clinical use if applied in conditions similar to this study. The combination of a continuous measure of cardiac output with other continuous physiologic monitoring (arterial and mixed venous oxygen saturation, oxygen consumption, etc.) may provide important information that no single parameter could achieve.

Recovery of cardiopulmonary reflexes in monkeys undergoing heart-lung transplantation.

After heart-lung transplantation in primates, cardiopulmonary reflexes were tested and shown to be present. The Hering-Breuer and cough reflexes were tested, as well as responses to an inhaled respiratory stimulant, vasodilator, and an intravenous anticholinesterase and antimuscarinic agent. Recovery of these responses, except to the anticholinesterase agent, suggests that reinervation occurs in autotransplanted organs in primates. The Hering-Breuer reflex was present at 1.9 and 2.2 months after the operation in two animals subjected to autotransplantation. These cardiopulmonary reflex responses were also demonstrated in two allograft recipients studied at 15 and 16.9 months after the operation. Return of protective reflexes such as coughing may be an important mechanism to prevent aspiration pneumonitis and other complications in humans.

Extra-adrenal pheochromocytoma: an unusual location.

A 14-year-old boy with a retrohepatic para-aortic pheochromocytoma demonstrates the potential difficulties of localization in an unusual extra-adrenal site of pheochromocytoma. Ultrasonography, computed tomography, metaiodobenzylguanidine scanning, and angiography with venous sampling failed to define the true anatomic location of this tumor. Collateral venous drainage produced confusing venous sampling data and represents a potential pitfall in the interpretation of these studies.

Effect of heparinization of catheters on pulmonary artery oximetry.

A clinical study was performed in two phases to determine whether pulmonary artery oximeter catheters that were impregnated or bonded with heparin would affect the accuracy of measurements of in vivo mixed venous oxygen saturation (Sv-O2). In phase 1, 40 patients were catheterized with either a heparin-impregnated or a plain pulmonary artery catheter. Blood was sampled at random times to correlate in vivo with in vitro Sv-O2 measurements. In phase 2, 16 patients who were not receiving systemic heparin therapy or aspirin and who had no coagulopathies were catheterized with either a heparin-bonded or a plain pulmonary artery catheter in a blinded order. In phase 1, a total of 364 blood samples were obtained from 40 patients. Linear regression analysis of the pooled data demonstrated y = 0.98x - 0.01, r = 0.93, P less than 0.001, and n = 141 with heparin-impregnated catheters; and y = 0.87x + 8.0, r = 0.81, P less than 0.001, and n = 223 with plain catheters. The mean difference (in vivo minus in vitro) revealed a similar error (-1.3 +/- 0.4 versus -1.4 +/- 0.4, respectively, mean +/- SE). The 95% confidence limits of an individual value (+/- 8.1 versus +/- 12.3) suggested slightly greater accuracy with heparin-impregnated catheters. In phase 2, a total of 134 blood samples were obtained from 16 patients. Linear regression analysis showed nearly equal performance with heparin-bonded and plain catheters (r = 0.97 versus r = 0.98, respectively) with similar slopes (1.0 versus 1.1, respectively) but different intercepts (-0.6 versus -8.4, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Pulmonary effects of crystalloid and colloid resuscitation from hemorrhagic shock in the presence of oleic acid-induced pulmonary capillary injury in the dog.

The effects of resuscitation with crystalloid and colloid solutions in the presence of increased pulmonary capillary permeability were studied. Twenty-four hours after oleic acid administration, dogs were anesthetized and bled to produce hemorrhagic shock. One hour later, resuscitation was performed with saline, 5% albumin, or 6% hydroxyethyl starch solution to restore and then maintain cardiac output at pre-oleic acid values for 6 h. Dogs were recovered and, 24 h later, were reanesthetized for final measurements. Oleic acid administration resulted in increases in pulmonary artery pressure, pulmonary vascular resistance, and extravascular lung water (EVLW). Resuscitation from hemorrhagic shock restored pulmonary hemodynamics to pre-hemorrhage levels and did not affect EVLW, PaO2, shunt fraction, dead-space-to-tidal-volume ratio, or pulmonary compliance. There were no differences in these parameters related to the choice of resuscitation fluid. Saline resuscitation markedly reduced plasma oncotic pressure and the plasma oncotic-pulmonary artery occlusion pressure gradient. Values for these two variables were markedly lower with saline than with colloid resuscitation. The authors conclude that the pulmonary effects of crystalloid and colloid solutions are similar in the presence of moderate increases in pulmonary capillary permeability.

Rapid assessment of ventilation by measurement of carbon dioxide elimination during high-frequency ventilation of kittens.

Monitoring of the effectiveness of ventilation is a significant problem during high-frequency ventilation (HFV). The time necessary to achieve equilibrium of the arterial tension of carbon dioxide (Paco2) following step changes in ventilation is appreciable, because of large body stores of CO2. Waiting for Paco2 to reach equilibrium is not only time-consuming but a potentially dangerous means of monitoring ventilator adjustments during HFV. Five kittens of mean +/- SD 1,082 +/- 383 gm weight were studied during HFV, both with normal lungs and lungs injured by saline lavage-induced surfactant depletion. The transcutaneous tension of carbon dioxide (Ptcco2) was monitored continuously to determine the time required to achieve equilibrium of Paco2 following a step change in ventilation. The rate of pulmonary CO2 elimination (VECO2) was measured immediately before and immediately after (less than 12 sec) step changes in ventilation and was used to predict the change in Paco2 achieved once equilibrium was reestablished. With normal lungs, equilibration time following step changes in ventilation was found to be approximately 20 minutes. After step decreases in ventilation of the injured lung, achieving equilibrium state took significantly longer, approximately 30 minutes. The Paco2 predicted was significantly related to the change in Paco2 achieved at equilibrium for both normal and injured lung studies. We concluded that direct monitoring of VECO2 during HFV may be a useful clinical monitoring technique, allowing rapid and accurate assessment of the efficiency of ventilation following step changes in ventilation and potentially assisting in optimizing ventilator settings.

Nasal continuous positive airway pressure in atelectasis.

Nasal continuous positive airway pressure (CPAP) has been widely and safely used in the treatment of sleep disorders but has not been previously utilized for therapy of pulmonary atelectasis in adults. We observed three patients with significant atelectasis which was refractory to conventional chest physiotherapy. Bronchoscopy was not a viable therapeutic option in any patient. Therapy with continuous nasal CPAP was initiated at 10 to 15 cm H2O. The patients tolerated the therapy well and had prompt resolution of atelectasis. Nasal CPAP may be an effective modality for therapy of pulmonary atelectasis in spontaneously breathing patients, particularly when conventional therapies are not tolerated or are ineffectual.

Leukotriene D4 increases extravascular lung water in the dog.

The peptide leukotrienes have been detected in animals that have received endotoxin injections and also have been associated with patients suffering from the adult respiratory distress syndrome (ARDS). The ability of leukotriene D4 (LTD4) to cause pulmonary capillary permeability changes was investigated in ten anesthetized mongrel dogs. Four dogs were used as controls and six dogs received intravenous LTD4 (0.25 microgram/kg). There was a variable response in that two treated animals showed no apparent effect of LTD4. Analysis of the results from the remaining four treated animals demonstrated a significant increase in extravascular lung water (EVLW) that peaked 3 hr after LTD4 from 5.4 +/- 0.6 to 10.3 +/- 0.5 ml/kg (P less than .01). In these four dogs, EVLW increased before slight, but statistically significant, rises in pulmonary artery wedge pressure (4 +/- 1 to 9 +/- 1 mm Hg, P less than .01) and mean pulmonary artery pressure (13 +/- 1 to 17 +/- 1 mm Hg, P less than .01) occurred. During the same period, cardiac output decreased 56 +/- 7% (P less than .01), but no change in airway resistance was observed. This study is the first in vivo demonstration that LTD4 directly alters pulmonary fluid balance in the dog. We conclude LTD4 can cause increases in EVLW and may be an important mediator of the permeability changes observed in various clinical events that lead to the adult respiratory distress syndrome.

Thermal dye double indicator dilution measurement of lung water in man: comparison with gravimetric measurements.

The thermal dye double indicator dilution technique for estimating lung water was compared with gravimetric analyses in nine human subjects who were organ donors. As observed in animal studies, the thermal dye measurement of extravascular thermal volume (EVTV) consistently overestimated gravimetric extravascular lung water (EVLW), the mean (SEM) difference being 3.43 (0.59) ml/kg. In eight of the nine subjects the EVTV -3.43 ml/kg would yield an estimate of EVLW that would be from 3.23 ml/kg under to 3.37 ml/kg over the actual value EVLW at the 95% confidence limits. Reproducibility, assessed with the standard error of the mean percentage, suggested that a 15% change in EVTV can be reliably detected with repeated measurements. One subject was excluded from analysis because the EVTV measurement grossly underestimated its actual EVLW. This error was associated with regional injury observed on gross examination of the lung. Experimental and clinical evidence suggest that the thermal dye measurement provides a reliable estimate of lung water in diffuse pulmonary oedema states.

Care of the adult patient during transport.

Interhospital transport of the critically ill patient involves maintaining the same quality of care that was present before transport. This requires planning for equipment, space, and personnel needs during transport, and instituting adequate pathophysiologically based treatment and stabilization prior to transport. Under such conditions, transport can be safely accomplished and have a positive impact on patient care.