Mary J. Njoku

Successful use of chronic epoprostenol as a bridge to liver transplantation in severe portopulmonary hypertension

BACKGROUND Portopulmonary hypertension, defined as mean pulmonary artery pressure >25 mmHg in the presence of a normal pulmonary capillary wedge pressure and portal hypertension, is a known complication of end-stage liver disease that has been associated with high morbidity and mortality at the time of liver transplantation. We have recently reported the successful treatment of portopulmonary hypertension with chronic intravenous epoprostenol and now report the first patient with severe portopulmonary hypertension successfully treated with epoprostenol who subsequently underwent successful liver transplantation. METHODS A patient with severe portopulmonary hypertension was treated with intravenous epoprostenol, 23 ng/kg/min, for a 4-month period, after which the portopulmonary hypertension resolved and the patient underwent successful liver transplantation. RESULTS The patient was discharged, continues to do well, and at 3 months is off epoprostenol with near normal pulmonary artery pressures. CONCLUSIONS Chronic epoprostenol, in conjunction with a multidisciplinary, well-planned perioperative evaluation and treatment plan, may be the answer to a heretofore untreatable disease.

The effects of increased abdominal pressure on lung and chest wall mechanics during laparoscopic surgery

We tested the hypothesis that increases in pressure in the abdomen (Pab) exerted by CO2 insufflation during laparoscopy would increase elastance (E) and resistance (R) of both the lungs and chest wall.We measured airway flow and airway and esophageal pressures of 12 anesthetized/paralyzed tracheally intubated patients during mechanical ventilation at 10-30/min and tidal volume of 250-800 mL. From these measurements, we used discrete Fourier transformation to calculate E and R of the lungs and chest wall. Measurements were made at 0, 15, and 25 mm Hg Pab in the 15 degrees head-down (Trendelenburg) posture and at 0 and 15 mm Hg Pab in the 10 degrees head-up (reverse Trendelenburg) posture. Lung and chest wall Es and Rs while head-down increased at Pab = 15 mm Hg, and both Es increased further at Pab = 25 mm Hg (P < 0.05). Both Es and Rs also increased while head-up at Pab = 15 mm Hg (P < 0.05), but increases in lung E and R were less than while head-down (P < 0.05). The increases in lung E and R at Pab = 15 mm Hg in either posture were positively correlated to body weight or body mass index, whereas the increases in chest wall E and R were negatively correlated to the same factors (P < 0.05). Lung and chest wall mechanical impedances increase with increasing Pab; the increases depend on body configuration and are greater while head-down. These changes should be considered in patients where increases in impedance may be critical, such as in obese patients and those with pulmonary disease. (Anesth Analg 1995;81:744-50)

Cytoablative therapy with combined resection and cryosurgery for limited bilobar hepatic colorectal metastases

BACKGROUND Cryosurgery can be employed in patients with unresectable hepatic metastases when the tumor size and the number of metastases are limited. However, local recurrence can result from incomplete ablation. We proposed a trial of complete cytoablation with a combined approach of cryosurgery and hepatic resection for patients with bilobar hepatic metastases. METHODS Seven patients underwent cryosurgery alone (CRYO). Seven additional patients underwent combined resection and cryosurgery (CRYO+RES) for bilobar metastases. RESULTS In the CRYO group, 5 of 7 patients had at least one centrally located tumor. All 5 of these patients had early recurrence at the site of ablation. In the CRYO+RES group complete ablation was achieved in 7 of 7. Two (28.6%) of these patients developed local recurrence. CONCLUSION Cytoablation of hepatic metastases can be safely achieved with combined hepatic resection and cryosurgery in selected patients. Long-term survival data are necessary before advocating widespread application of this approach.

Changes in lung and chest wall properties with abdominal insufflation of carbon dioxide are immediately reversible.

Previously we have reported that large increases in lung and chest wall elastances as well as lung resistance occur with abdominal insufflation of carbon dioxide during laparoscopic surgery.To examine whether these effects were reversible with abdominal deflation, we calculated lung and chest wall elastances and resistances from measurement of airway flow and pressure and esophageal pressure in 17 anesthetized/paralyzed patients undergoing laparoscopic surgery. Measurements were made immediately prior to abdominal insufflation and after deflation. Lung and chest wall elastances and resistances were not changed from baseline (P > 0.05), although total respiratory elastance remained slightly increased compared to baseline (P < 0.05). The change in total respiratory elastance did not correlate with abdominal insufflation time, surgical site, smoking history, or physical characteristics of the patients. There were no differences in frequency and tidal volume dependences of the elastances and resistances before and after abdominal insufflation (P > 0.5). We conclude that residual changes in respiratory mechanics caused by carbon dioxide insufflation during laparoscopic surgery are minor, and that the reported compromise of respiratory function indicated by pulmonary function tests after laparoscopy does not appear to be due to changes in passive mechanical properties of the lungs or chest wall. (Anesth Analg 1996;82:501-5)

Successful emergency transplantation of a liver allograft from a donor maintained on extracorporeal membrane oxygenation.

The critical shortage of cadaveric donors for organ transplantation has led many transplant centers to accept life-saving organs from donors who would have previously been refused for transplantation. We report a novel case of the use of a liver allograft from a donor whose oxygen delivery was maintained by extracorporeal membrane oxygenation (ECMO) for 29 days before suffering an anoxic brain injury from ECMO dysfunction. Liver transplantation was successfully performed in a patient with fulminant hepatic failure. Immediate graft function was obtained in the recipient, with full neurologic recovery and return to gainful employment 4 months after transplantation. ECMO may provide an intriguing option for the maintenance of organ function in the critically unstable brain-dead organ donor to salvage organs for transplantation. Further studies are currently underway.

Haemoglobin-based oxygen carriers: indications and future applications

This article describes current oxygen-carrying solutions, four new products and new indications to increase the benefit/risk ratio of haemoglobin-based oxygen carriers compared to blood. Indications include when blood is not available, if blood is contaminated, is refused or contraindicated, and for organ preservation.

‘Big data’ approaches to trauma outcome prediction and autonomous resuscitation

Massive clinical digital data routinely collected by high throughput biomedical devices provide opportunities and challenges for optimal use. This article discusses how such data are used in learning prediction models at level 1 trauma centres to support decision making in trauma patients.

Patients with chronic endocrine disease.

This article summarizes the key features and clinical considerations related to preoperative management and planning for the care of patients of common endocrine disorders (diabetes mellitus, adrenal insufficiency, thyroid disease), a less common disorder but one that has significant perioperative implications (acromegaly), and 2 disorders for which preoperative management is essential to good postoperative outcomes (pheochromocytoma and carcinoid syndrome). There are few evidence-based guidelines for preoperative management of chronic endocrine disease; hence, this review is based on recent subspecialty society consensus guidelines and professional society clinical practice recommendations.