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Biomedical subjects

M J Peacock

Publications and source records attributed to M J Peacock.

14 recordsLinked to original sources
PubMed2001

Lung volume reduction surgery in emphysema: a systematic review.

The aim of this study was to systematically review the literature regarding the safety and efficacy of lung volume reduction surgery (LVRS) in patients with emphysema. Studies on LVRS to August 2000 were identified using MEDLINE, Embase, Current Contents, and the Cochrane Library. Human studies of patients with upper, lower or diffuse distributions of emphysema were included. All types of bullous emphysema were excluded. A surgeon and researcher independently assessed the retrieved articles for their inclusion in the review. When LVRS was compared with medical management, at 2 years LVRS was associated with a higher FEV1 and at least equivalent survival. The use of staple excision of selected areas of lung appeared to be more efficacious than laser ablation. There is insufficient evidence to show preference for median sternotomy or videoscopically assisted thoracotomy, as the more safe and efficacious procedure. In highly selected patients with emphysema LVRS is deemed an acceptable treatment. To fully evaluate the safety and efficacy of LVRS, outcomes beyond 2 years must be included. The results of prospective randomized trials between medical management and LVRS, now in progress, are essential before a final assessment can be made.

Hospital Mortality↗
PubMed2001

Speed of collapse of the non-ventilated lung during one-lung anaesthesia: the effects of the use of nitrous oxide in sheep.

By enhancing gaseous uptake from the non-ventilated lung during procedures performed thoracoscopically, the rapid diffusion properties of nitrous oxide would be expected to speed lung collapse and so facilitate surgery. To assess the effect of nitrous oxide on the speed of absorptive lung collapse, a study was conducted using 11 anaesthetised sheep. Speed of collapse was assessed in an indirect manner by recording the time required in a closed-chest situation for the airway pressure distal to a single lung airway occlusion to decrease to - 1.0 kPa. The influence of nitrous oxide was assessed by comparing the time taken for this decrease in airway pressure when the animal was being mechanically ventilated with 50% nitrous oxide in oxygen with the time taken when using 100% oxygen. In all assessments, it was found that the decrease in airway pressure to - 1.0 kPa occurred in a shorter time when nitrous oxide was used. The findings lend support to the hypothesis that during thoracoscopic surgery, mechanical lung ventilation with an oxygen/nitrous oxide mixture will increase the rate of gaseous uptake from the non-ventilated lung and so hasten its absorptive collapse.

Air Pressure↗
PubMed2001

Speed of collapse of the non-ventilated lung during single-lung ventilation for thoracoscopic surgery: the effect of transient increases in pleural pressure on the venting of gas from the non-ventilated lung.

A study of 10 anaesthetised patients placed in the lateral position for thoracoscopic surgery assessed whether transient increases in pleural pressure on the side of the non-ventilated lung might increase the speed at which gas vents from that lung. The transient increases in pleural pressure were generated by the mediastinal displacement that occurs with each inspiratory phase of positive pressure ventilation of the dependent lung. When combined with a unidirectional valve allowing gas to flow out of the non-ventilated lung, and a second valve allowing ambient airflow into, but not out of, the thoracic cavity via an initial thoracoscopy access site, this mediastinal displacement could conceivably serve to 'pump' gas out of the non-ventilated lung. Using the four different combinations of valve inclusion or omission, the volume of gas that vented from the non-ventilated lung into a measuring spirometer was recorded during a 120-s measurement sequence. It was found that the speed of venting was not increased by the transient increases in pleural pressure, and that in all but one of a total of 34 measurement sequences, venting had ceased by the end of the sequence. Gas venting was a mean (SD) of 85.5 (11.9)% complete in 25 s (five breaths), and 96.6 (6.1)% complete in 60 s. This prompt partial lung collapse very likely reflected the passive elastic recoil of the lung, while the failure of transient increases in pleural pressure to result in ongoing venting of gas was probably a consequence of airways closure as the lung collapsed. It is concluded that techniques that aim to speed lung collapse by increasing pleural pressure are unlikely to be effective.

Adolescent↗
PubMed2000

Lobectomy for cavitating lung abscess with haemoptysis: strategy for protecting the contralateral lung and also the non-involved lobe of the ipsilateral lung.

We describe the anaesthetic management of a patient undergoing lobectomy for cavitating lung abscess complicated by haemoptysis. Surgery for lung abscess is one of the absolute indications for the use of a double-lumen tube (DLT). Because pus or blood could impede fibreoptic-assisted DLT placement, a traditional, blind placement of the DLT was performed. To protect the uninvolved parts of the operated lung, ventilation of the lung with the abscess was not performed until the resection of the involved lobe had been completed.

Adult↗
PubMed1999

Gas movement in the nonventilated lung at the onset of single-lung ventilation for video-assisted thoracoscopy.

To assess the potential for atmospheric nitrogen to enter the nonventilated lung following the initiation of single-lung ventilation, the nonventilated lung of 10 patients undergoing video-assisted thoracoscopy was connected to the air in a water-filled spirometer, and gas movement out of and back into the lung was measured. Airway pressure from both lungs and pleural pressure from the nonventilated side were also measured. With each breath of positive-pressure ventilation to the ventilated lung prior to the thoracic cavity being opened to the atmosphere, the pressure transmitted to the opposite hemithorax generated a mean (range) tidal movement of gas in the nonventilated lung of 134 (65-265) ml. In addition, ongoing gas exchange resulted in a progressive influx of gas from the spirometer over the 110-120 s measurement period of a mean (range) volume of 155 (70-320) ml. This easily preventable influx of atmospheric nitrogen could, in theory, predispose to arterial desaturation and to delayed lung collapse after the parietal pleura is opened.

Adolescent↗
PubMed1999

Ambient pressure oxygen reservoir apparatus for use during one-lung anaesthesia.

An ambient pressure oxygen reservoir bag apparatus for connecting to the nonventilated lung as soon as single-lung ventilation is initiated is described. The theoretical benefits are the facilitation of collapse of the lung on the side of surgery and a reduced likelihood of arterial desaturation. Although these main benefits are yet to be proven, the authors believe that the weight of theoretical argument and practical observation serves to justify the use of the apparatus while the outcome of suitably designed clinical trials is awaited. It can be used for all one-lung anaesthetics and is especially recommended for thoracoscopic surgery, where temporary re-expansion of the nonventilated lung is either counter-productive or contraindicated, and where there is a possibility that lung collapse may be delayed.

Drug Delivery Systems↗
PubMed1992

Myositis ossificans in childhood.

Myositis ossificans is a benign, localized, ossifying lesion of soft tissues that is rarely reported in young children. This paper describes two cases found in a search of the surgical biopsy files of the Adelaide Children's Hospital over the 30 yr period from 1962 to 1991, in boys both aged 7 yrs. Diagnosis was assisted by combined clinical, radiological and histopathological information (including an adequate well-orientated biopsy in Case 1 that demonstrated the characteristic growth pattern) enabling differentiation from other possibilities such as fibrodysplasia ossificans progressiva.

Child↗
PubMed1976

Pulmonary blastoma.

Pulmonary blastoma is now accepted as a distinctive neoplasm. It remains rare, and only 28 cases have been reliably recorded. A further two cases are now reported, and the previous literature is reviewed. There are no specific clinical or radiological features of pulmonary blastoma. The presentation can be that of any other pulmonary tumour although a peripheral situation is usual and a large size is often attained before detection. Pulmonary blastoma is a mixed tumour with malignant epithelial and connective tissue components with a distinctive resemblance to fetal lung. The treatment of choice is surgical excision but the overall prognosis is poor. It is doubtful whether the tumour has a true blastomatous origin.

Adolescent↗