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Biomedical subjects

J N Baxter

Publications and source records attributed to J N Baxter.

At least 55 records · Page 3Linked to original sources
PubMed1994

Circulating intact parathyroid hormone levels in acute pancreatitis.

Serum levels of parathyroid hormone (PTH), calcium and albumin were measured daily for 5 days in 41 selected patients with moderate to severe acute pancreatitis. The PTH level was measured by means of a two-site immunoradiometric assay specific for the intact polypeptide. A rise in PTH level was observed more commonly in patients with a complicated or fatal outcome than in those with an uncomplicated course (14 of 16 versus six of 25 patients, P < 0.001). Although PTH levels were variable in the presence of hypocalcaemia, raised concentrations were found more frequently in patients with complications (seven of eight versus two of seven without complications, P = 0.035). This study confirms that an appropriate rise in PTH level occurs in response to the hypocalcaemic stimulus in patients with acute pancreatitis.

Acute Disease↗
PubMed1994

Helium pneumoperitoneum for laparoscopic cholecystectomy: ventilatory and blood gas changes.

Laparoscopic cholecystectomy with carbon dioxide pneumoperitoneum may result in hypercarbia and acidosis in patients with cardiorespiratory disease. The aim of the present study was to assess helium as an alternative to carbon dioxide for creating the pneumoperitoneum. Ventilation requirements and carbon dioxide levels were assessed at the beginning and end of laparoscopic cholecystectomy using helium (n = 30) and carbon dioxide (n = 30) pneumoperitoneum. Insufflation with helium did not result in an increase in ventilation requirement although, like carbon dioxide pneumoperitoneum, it was associated with a mean rise in peak airway pressure (of 7 cmH2O; P < 0.001). There was also a 3.2-kPa increase in the alveolar-arterial oxygen gradient with helium (P = 0.006). Carbon dioxide pneumoperitoneum was associated with a significant rise in arterial carbon dioxide levels, despite increasing ventilation. Four patients with helium pneumoperitoneum had surgical emphysema for 5 days. Helium may be a suitable alternative to carbon dioxide for creating pneumoperitoneum in patients with severe cardiorespiratory disease. However, because of its low water solubility helium has a lower safety margin than carbon dioxide in the rare event of gas embolism.

Adult↗
PubMed1994

Splanchnic blood flow changes in the presence of hepatic tumour: evidence of a humoral mediator.

Intrahepatic tumour is associated with alterations in splanchnic haemodynamics. To investigate the hypothesis that these are the result of a circulating vasoactive agent, rat small bowel segments were cross-perfused with arterial blood from groups (n = 12) of paired tumour-bearing (intrahepatic HSN sarcoma) and control rats. The vascular resistance of the segment was significantly greater during perfusion by tumour-bearing animals (91.6 mmHg ml-1 min, s.e. 21.5, vs 51.7 mmHg ml-1 min, s.e. 7.4, P < 0.05), suggesting that intrahepatic tumour may be associated with a circulating vasoactive agent. A similar mechanism may underlie changes in the hepatic perfusion index in patients with liver metastases.

Animals↗
PubMed1994

Respiratory function after injection sclerotherapy of oesophageal varices.

Arterial oxygen tension (Pao2), carbon dioxide tension (PaCO2), and vital capacity were measured preoperatively and one day postoperatively in patients with chronic hepatic cirrhosis having elective oesophageal injection sclerotherapy under general anaesthesia. The results were compared with the same measurements made in patients with chronic cirrhosis anaesthetised and scheduled to have injection sclerotherapy under general anaesthesia but who, because of variceal obliteration, only had an oesophagogastroscopy. In the injected group PaO2 decreased by 9.3 (3.0) mm Hg (1.2 (0.4) kPa) (mean (SEM)) (p < 0.02) but in the controls did not change. The difference between the two groups was significant (p < 0.02). Vital capacity decreased by 0.39 (0.08) litres (BTPS) (p < 0.01) after injection sclerotherapy but in the controls did not change. Again the difference between the two groups was significant (p < 0.02). In the injected group there was a significant correlation between the change in PaO2 and the percentage change in vital capacity (r = 0.787, p < 0.01) but no such relation was seen in control subjects. These results suggest that oesophageal injection sclerotherapy is associated with a restrictive defect in respiratory function one day after the injection caused, possibly, by sclerosant embolising to the lung.

Esophageal and Gastric Varices↗
PubMed1994

Somatostatin: an alternative to sclerotherapy?

BACKGROUND: The mortality rate of bleeding from oesophageal varices (30-40%) makes it one of the most serious emergencies today. Since in 30-40% of patients varices are actively bleeding, urgent control is mandatory for preventing the patient from dying of hypovolaemic shock. ANALYSIS OF THE DIFFERENT METHODS: Various reports have shown the efficacy of injection sclerotherapy, one session controlling bleeding in 75-80% of patients, and a second increasing the success rate to 90-95%. However, the facilities for 24-h endoscopy and the expertise are not always available in the hospital. Therefore, there is a need for an effective stop-gap therapy for controlling variceal bleeding until definitive therapy can be carried out. Comparisons of various drugs have provided conflicting results. It is not clear whether combined vasopressin and nitroglycerin is superior to injection sclerotherapy in the acute control of variceal haemorrhage. A randomized controlled trial has showed somatostatin to be as effective as injection therapy in the control of acute variceal bleeding and incidence of recurrent bleeding in the first 5 days after initiation of therapy. CONCLUSION: Somatostatin is a safe and effective treatment for the control of acute variceal haemorrhage and for preventing early rebleeding.

Acute Disease↗
PubMed1994

Laparoscopic and minilaparotomy cholecystectomy: a randomized trial comparing postoperative pain and pulmonary function.

BACKGROUND: Upper abdominal surgery is associated with severe postoperative pain and a concomitant reduction in pulmonary function and oxygen saturation. Laparoscopic cholecystectomy is said to result in less postoperative pain compared with open cholecystectomy. METHODS: In a pragmatic, randomized trial, postoperative pain, opiate analgesic consumption, oxygen saturation, and pulmonary function (forced vital capacity, forced expiratory volume in 1 second, and peak expiratory flow rate) were assessed after laparoscopic (n = 67) and minilaparotomy (n = 65) cholecystectomy. RESULTS: Compared with minilaparotomy cholecystectomy, laparoscopic cholecystectomy was associated with lower linear analogue pain scores (median 40 vs 59, p < 0.001), lower patient-controlled morphine consumption (median 22 vs 40 mg, p < 0.001), a smaller reduction in postoperative pulmonary function (mean peak expiratory flow rate 64% of preoperative value vs 49%, p < 0.001), and better oxygen saturation (mean 92.9% vs 91.2%, p = 0.008). CONCLUSIONS: This study confirms that the postoperative pain and pulmonary changes associated with upper abdominal surgery are significantly reduced by the laparoscopic technique. These findings suggest that laparoscopic cholecystectomy may result in a reduced risk of postoperative pulmonary complications.

Adult↗
PubMed1993

Relationship between intra-abdominal and intrarectal pressure in the proctometrogram.

During normal defaecation the intrarectal pressure increases but, in the absence of a reference catheter in the pelvis, the contribution of abdominal straining and rectal contraction to this rise is unclear. Anorectal manometry was performed in ten consecutive women with no gastrointestinal symptoms in an attempt to measure intrapelvic pressure using a catheter in the bladder. During filling the mean (s.e.m.) rectal pressure increased from 2(1) to 18(4) cmH2O. The mean(s.e.m.) intravesical pressure remained unchanged at 2(1) cmH2O. Evacuation of the rectal balloon produced an increase in mean (s.e.m.) intrarectal pressure from 18(4) (end-filling pressure) to 68(15) cmH2O. The mean (s.e.m.) intravesical pressure increased from 2(1) to 51(18) cmH2O. The true intrarectal pressure (intrarectal minus intravesical) did not rise during defaecation. The rise in intrarectal pressure during rectal evacuation occurs by increased intrapelvic pressure alone.

Abdominal Muscles↗
PubMed1993

Idiopathic slow-transit constipation.

Until recently, the surgical management of idiopathic slow-transit constipation had remained unchanged since the condition was first described by Arbuthnot Lane in 1908. Although colectomy and ileorectal anastomosis is a successful treatment for the majority of patients, symptoms persist or are worse in some cases following such surgery. The previously inaccessible colon is now an area of interest in both health and disease; recent observations on aetiology, clinical investigation, neuropathology and surgical outcome lead us to question the rationale of colectomy for all patients with severe constipation.

Anastomosis, Surgical↗
PubMed1993

Ventilatory and blood gas changes during laparoscopic and open cholecystectomy.

As part of a randomized trial, ventilatory and arterial blood gas changes were assessed during open (n = 30) and laparoscopic (n = 30) cholecystectomy. Measurements were made during anaesthesia before the start of surgery and at the time of removal of the gallbladder. Despite an increase in minute ventilation from a mean(s.d.) of 5.7(1.4) to 6.1(1.2) litres, mean(s.d.) arterial carbon dioxide tension (PaCO2) rose from 5.3(0.9) to 6.0(0.9) kPa during laparoscopic cholecystectomy. End-tidal carbon dioxide tension (PE'CO2) had poor precision in predicting PaCO2 (95 per cent interval of agreement -0.61 to 1.93 kPa). Mean(s.d.) peak airway pressure increased from 17(4) to 23(4) cmH2O. The mean PaCO2--PE'CO2 value did not change significantly, although there was significant within-patient variation. Arterial oxygen levels did not change significantly. By comparison, no clinically significant changes in ventilation or blood gas values occurred during open cholecystectomy. In conclusion, laparoscopic cholecystectomy requires a substantial but variable increase in minute ventilation to compensate for carbon dioxide absorption from the peritoneum.

Adult↗
PubMed1993

Comparison of metabolic responses to laparoscopic and minilaparotomy cholecystectomy.

This randomized study compared the metabolic responses to laparoscopic cholecystectomy (n = 10) and minilaparotomy cholecystectomy with a 5-7-cm incision (n = 10). Venous blood samples were taken before operation and at 3, 6, 9, 12, 18, 24, 48, 72 and 168 h after incision and analysed for levels of C-reactive protein, interleukin 6, cortisol, albumin, transferrin, iron, fibrinogen, fibrin degradation products and polymorphonuclear elastase, and for neutrophil and lymphocyte counts. Urine samples (24 h) were analysed for urea, creatinine, 3-methylhistidine and catecholamines. The magnitude of the metabolic changes from baseline levels was quantified by calculating areas under each individual curve. A significant metabolic response with a similar time course and magnitude of changes occurred after laparoscopic and minilaparotomy cholecystectomy but with wide variation in magnitude between individuals.

Adult↗
PubMed1993

Neoterminal ileal blood flow after ileocolonic resection for Crohn's disease.

Endoscopic laser Doppler flowmetry was used to measure neoterminal ileal blood flow in 16 patients who had undergone ileocolonic resection for Crohn's disease and had since remained clinically and biochemically free of disease, and eight control patients who had undergone similar surgery for colonic carcinoma. Four patients with clinically active Crohn's disease of the terminal ileum were also studied. Neoterminal ileal recurrence in those with inactive Crohn's disease was graded endoscopically. The median and minimum of five local blood flow measurements performed in each patient were inversely correlated with the endoscopic recurrence grade (r = -0.52, p = 0.04 and r = -0.63, p = 0.01 respectively). Relative to the control group, median blood flow was non-significantly lower in the inactive Crohn's disease group as a whole (p > 0.05) but was significantly reduced in patients with active disease (p = 0.02). A progressive reduction in tissue perfusion may accompany recurrence of Crohn's disease while at a subclinical stage.

Adult↗
PubMed1993

Somatostatin and somatostatin analogues--are they indicated in the management of acute pancreatitis?

Somatostatin was first suggested for the treatment of acute pancreatitis more than 15 years ago but despite many studies, its role in the management of this condition remains unclear. The experimental and clinical studies are reviewed and the physiological actions of somatostatin, which may influence the course of acute pancreatitis are examined. It is concluded that although some reports suggest a trend towards improved survival and lessened complication rate with somatostatin treatment, insufficient evidence of benefit exists to support the use of somatostatin or its analogue in the treatment or prophylaxis against acute pancreatitis in routine clinical practice.

Acute Disease↗