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Biomedical subjects

H J Proctor

Publications and source records attributed to H J Proctor.

At least 19 recordsLinked to original sources
PubMed1991

Acute appendicitis following blunt abdominal trauma. Incidence or coincidence?

Inflammation of the appendix is a common cause of acute abdominal pain. The etiology and pathophysiology of appendicitis have been well described. The initiating factor often is obstruction of the appendiceal lumen by inspissated stool, barium, food, parasites, or hyperplastic lymphoid tissue. Two patients have been identified who developed appendicitis temporally related to blunt abdominal trauma, without other clear etiology. Although absolute documentation of trauma as an etiologic factor in these cases is difficult, theoretical mechanisms for the occurrence are discussed. In the setting of right lower quadrant pain following mild to moderate blunt abdominal trauma, acute appendicitis should be considered as a possibility.

Abdominal Injuries↗
PubMed1990

Biliary diversion for pancreatic carcinoma: matching the methods and the patient.

Two hundred eleven patients with adenocarcinoma of the pancreas were reviewed. Seventy had surgically constructed biliary-enteric anastomoses. Forty-two had percutaneous/endoscopic placement of biliary diversion catheters. Surgical biliary diversion was associated with discharge at 7 +/- 2 days postoperatively. Only five patients required subsequent reoperations for anastomotic failure secondary to continued tumor growth. Sixty-one percent of percutaneous/endoscopic catheters were associated with septicemia, and 27% occluded (average life span 36 days). Hospital days averaged 20 days of an average 64-day patient life span. After evaluation of computed tomographic scans and surgical findings, patients' diseases were arbitrarily divided into (A) local, (B) regional, and (C) distant spread. Survival was 417,300, and 53 days, respectively. In view of the morbidity associated with the percutaneous/endoscopic catheter, we recommend that its use be restricted to Group C patients.

Adenocarcinoma↗
PubMed1988

Cervical vessel injury after blunt trauma.

Blunt trauma accounts for 3% to 10% of cervical vessel injuries. Death and severe neurologic impairment have been reported in more than 80% of blunt carotid injuries. In our recent experience, 10 patients sustained 18 blunt cervical arterial injuries: two internal carotid artery (ICA) dissections, three ICA transections with pseudoaneurysm, five ICA thromboses, two vertebral artery dissections, one vertebral artery transection with pseudoaneurysm, one vertebral artery thrombosis, one minimal vertebral artery injury, and three caroticocavernous fistulas. A delay of more than 12 hours in making the diagnosis occurred in seven of the 10 patients. The mental status was initially normal in seven patients. The subsequent development of focal neurologic findings incongruent with CT scanning of the head prompted four-vessel angiography. Treatment was individualized and included supportive management, intravenous heparin, ligation, extracranial-intracranial bypass, and radiologic embolization. We have developed an angiographic classification that may aid management. Early angiography in patients with neurologic findings incongruent with head CT scan or in whom a normal sensorium and hemiparesis are present may permit improved outcomes. We advocate direct operative repair for accessible lesions of recent onset. For surgically inaccessible lesions, those with delayed presentation or in some cases with a fixed neurologic deficit, intravenous heparin can be started and follow-up angiography, head CT scanning, and the patient's clinical status determine further therapy.

Adult↗
PubMed1988

Failure of autoregulation after closed head injury: an experimental model.

Cats were subjected to a 3.5-atm fluid percussion impact administered to the cerebral cortex. Near-infrared spectrophotometry (NIRS) was used to measure the quantity of oxyhemoglobin and total hemoglobin in the illuminated tissue as well as the cytochrome a, a3 redox state. Corroborative data were obtained by freezing brains with liquid nitrogen and measuring cortical concentrations of ATP, creatine phosphate (CP), and lactate. Immediately postimpact there was a rise in mean arterial pressure with a 38% increase of highly oxygenated blood and a shift toward oxidation in the cytochrome a, a3 redox state. By 4 hours postimpact, cytochrome a, a3 was becoming progressively reduced despite the persistence of hyperemia. This was associated with a significant (p less than 0.01) decrease in ATP and CP concentration. Additional studies in which a 0.5-sec, 100-v electrical seizure was induced before and after fluid percussion demonstrated significant differences in seizure response, indicating a failure of autoregulation.

Adenosine Triphosphate↗
PubMed1986

Effect of nifedipine on cerebral high-energy phosphates after cardiac arrest and resuscitation in the rat.

We studied the effect of nifedipine, a calcium entry blocker, on the recovery of cerebral adenosine triphosphate (ATP), creatine phosphate (CP), and lactate levels following resuscitation from cardiac arrest. Using the cardiac arrest and resuscitation model of de Garavilla, Babbs, and Tacker with an arrest time of eight minutes, 76% of the animals arrested were resuscitated with an average intermittent abdominal compression-CPR time of 3.3 minutes. Rats were assigned randomly to the following groups: nonischemic; eight minutes of arrest without resuscitation; and postresuscitation treatment with either IV normal saline; 3 micrograms/kg nifedipine; 10 micrograms/kg nifedipine; or 30 micrograms/kg nifedipine. Treated animals were sacrificed at either 20 or 120 minutes thereafter. As expected, after eight minutes of cardiac arrest, the levels of ATP and CP dropped to near 0 and rebounded in all resuscitated animals. By 120 minutes after resuscitation, rats given the 10-micrograms/kg dose of nifedipine had levels of ATP equivalent to nonischemic values. Return of CP values to nonischemic levels was seen only at the 3-micrograms/kg dose and was independent of time of measurement. The ATP and CP levels in these nifedipine-treated groups were significantly better when compared to saline-treated controls. There were no treatment-dependent differences in lactate levels. We conclude that clinically appropriate doses of nifedipine had a beneficial effect on the recovery of cerebral high-energy phosphates after cardiac arrest and resuscitation.

Adenosine Triphosphate↗
PubMed1986

Direct noninvasive assessment of brain metabolism during increased intracranial pressure: potential therapeutic vistas.

Intracranial pressure was increased in cats by infusing 'mock' CSF intracranially, thus decreasing cerebral perfusion and oxygenation. The cats then randomly received either 50% O2 or 50% O2-5% CO2 by inhalation. As monitored by in vivo near-infrared spectroscopy (NIR), no improvement was noted after 50% O2 whereas 50% O2-5% CO2 resulted in increased perfusion, an oxidation of cytochrome a,a3, an increase in oxyhemoglobin, and reduced quantities of de-oxyhemoglobin (p less than 0.01) despite a further increase in intracranial pressure. The authors conclude that: NIR is a useful means of noninvasively and directly assessing brain metabolism and has advantages over simple ICP monitoring; and continued investigations of CO2 as a possible therapeutic modality after head injury appear warranted.

Animals↗
PubMed1985

Near infrared spectrophotometry: potential role during increased intracranial pressure.

Two experiments were conducted to assess the feasibility of near infrared spectrophotometry (niroscopy) to directly monitor the effects of increased intracranial pressure on brain metabolism. Intracranial pressure (ICP) was increased in cats by subarachnoid infusion of a "mock" CSF solution. Cytochrome a,a3 redox state, oxyhemoglobin, deoxyhemoglobin and cerebral blood flow were non-invasively and continuously monitored by niroscopy. The results of both experiments indicated that untreated increases in ICP correlated with a reduction in cytochrome a,a3 redox state (p less than 0.01), a decrease in the quantity of oxyhemoglobin and cerebral blood flow (p less than 0.01), and an increase in deoxyhemoglobin. This study suggests that niroscopy has the potential for providing noninvasively and continuously data assessing brain metabolic activity. The excellent correlations obtained with simultaneous direct measurements of intracranial pressure make this an attractive method for eventual application to humans at risk for increased intracranial pressure. The value of niroscopy is even more evident in Exp. II where it can be seen that knowledge only of ICP would give the physician a false sense of security, whereas direct, non-invasive, continuous assessment of brain perfusion and oxygenation may well prove to be more appropriate parameters to monitor.

Animals↗
PubMed1985

A noninvasive method for monitoring the effects of increased intracranial pressure with near infrared spectrophotometry.

Two experiments were conducted to assess the feasibility of near infrared spectrophotometry (niroscopy) to monitor directly the effects of increased intracranial pressure on brain metabolism. ICP was increased in cats by subarachnoid infusion of a "mock" CSF solution. Cytochrome a,a3 redox state, oxyhemoglobin, deoxyhemoglobin and cerebral blood flow were noninvasively and continuously monitored by niroscopy. The results of both experiments indicated that changes in ICP correlated with a reduction in cytochrome a,a3 redox state (p less than 0.01), a decrease in the quantity of oxyhemoglobin and cerebral flow (p less than 0.01) and an increase in deoxyhemoglobin. The study results suggest that niroscopy has the potential for providing noninvasive and continuous data for assessing brain metabolic activity. The correlations obtained with simultaneous measurements of intracranial pressure make this an attractive method for application to those at risk for increased intracranial pressure.

Animals↗
PubMed1979

Extracorporeal membrane oxygenation in severe acute respiratory failure. A randomized prospective study.

Nine medical centers collaborated in a prospective randomized study to evaluate prolonged extracorporeal membrane oxygenation (ECMO) as a therapy for severe acute respiratory failure (ARF). Ninety adult patients were selected by common criteria of arterial hypoxemia and treated with either conventional mechanical ventilation (48 patients) or mechanical ventilation supplemented with partial venoarterial bypass (42 patients). Four patients in each group survived. The majority of patients suffered acute bacterial or viral pneumonia (57%). All nine patients with pulmonary embolism and six patients with posttraumatic acute respiratory failure died. The majority of patients died of progressive reduction of transpulmonary gas exchange and decreased compliance due to diffuse pulmonary inflammation, necrosis, and fibrosis. We conclude that ECMO can support respiratory gas exchange but did not increase the probability of long-term survival in patients with severe ARF.

Acute Disease↗
PubMed1979

Surgery for chronic pancreatitis. Drainage versus resection.

A retrospective study of 49 patients with chronic obstructive and chronic calcific pancreatitis is presented. All patients were operated upon and underwent either a partial pancreatectomy or internal drainage of the ductal system into a Roux-en-Y loop of jejunum. The criteria for selection of operation are discussed, and the follow-up of the two operative groups is given. In patients selected as described, internal drainage provided better relief of pain and was accomplished with a lower operative mortality and morbidity and with less postoperative pancreatic insufficiency.

Adult↗
PubMed1979

Effects of hypoxia and hypotension on oxygen delivery in the brain.

Failure of microvascular re-perfusion, no reflow, of the brain after a period of ischemia has been proposed as the etiology of the cerebral dysfunction frequently seen in patients after resuscitation from hemorrhagic shock. For this investigation rats were stressed by subjecting them to a period of combined hypoxia and hypotension followed by resuscitation. Micro-oxygen electrodes measured brain oxygen tension, thus allowing an assessment of the distribution of cerebral blood flow, during stress and after resuscitation. After resuscitation, a hyperemic response was noted, followed by gradual return of some areas of the brain to normal perfusion, while other areas remained hyperemic for at least 2 hours post-resuscitation. On the basis of these results there appears to be no support for the no-reflow hypothesis. These data imply that therapeutic modalities aimed at increasing cerebral blood flow and oxygenation in the post-resuscitation period are insufficient in themselves for improved survival of patients sustaining a hypotensive, hypoxic episode.

Animals↗
PubMed1979

Pancreatic and duodenal injuries: morbidity and mortality of surgical management.

A retrospective review of pancreatic injury is presented. Twenty-five cases in which the pancreatic injury was either the sole or major injury were selected from over 100 cases of pancreatic injury admitted during the period 1970 to 1977. Eight pancreatic injuries resulted from blunt trauma and 17 from penetrating trauma. Two methods of treatment were compared, drainage alone versus duodenal diverticularization and/or distal resection. There were no deaths. Of the 15 patients treated by drainage alone, 14 (93%) developed postoperative complications, as compared to 20% (two of ten patients) treated by diverticularization and/or distal resection.

Drainage↗