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Biomedical subjects

J B Cone

Publications and source records attributed to J B Cone.

At least 37 records · Page 2Linked to original sources
PubMed1988

Surgical complications of thermal injury.

Aggressive control of intragastric pH in the burn patient has essentially eliminated upper gastrointestinal bleeding. The recent spectrum of complications in the thermally injured patient has shifted. Vascular occlusion and missed associated injury were the most frequent early complications in this review. Those complications occurring late in the course were attributed to sepsis originating in the burn wound. The common diagnostic error was to blame the burn injury for the patient's signs and symptoms. A high index of suspicion of an occult process must be exercised when caring for the burn patient who has burn shock with a decreasing hematocrit value or a compartment syndrome that does not respond to escharotomy or fasciotomy or the septic patient with a clean burn wound.

Adolescent↗
PubMed1988

The effect of staged burn wound closure on the rates of heat production and heat loss of burned children and young adults.

The sequential metabolic studies of nine severely burned patients were examined retrospectively. Information analyzed included heat production (M), partitioned heat loss (HL), the percentage of the body surface area open wound (% open wound) and skin (TS) and rectal (TR) temperatures. The reduction in the hypermetabolic response correlated with the number of days postburn (DPB), % open wound, average body temperature (TB = 0.8TR + 0.2TS) and evaporative heat loss (EV) (r = 0.62, 0.55, 0.56, 0.63, respectively). However, decrements in metabolic rate between sequential studies correlated only with the change in % open wound and the change in EV (r = 0.41 and 0.49, respectively). While changes in heat loss are not capable of predicting all of the variation in metabolic rate, burned patients demonstrate an increase in heat production largely secondary to the inability to conserve heat effectively in the periphery. This response is compounded by an altered central thermoregulation.

Adolescent↗
PubMed1987

Beneficial effects of a hypertonic solution for resuscitation in the presence of acute hemorrhage.

Crystalloid solutions such as Ringer's lactate have become the standard for initial volume replacement after hemorrhage. Although the relative merits of blood, colloid, and crystalloid have been extensively studied, little attention has been directed toward determining the optimal composition of the crystalloid solution. Based on the beneficial properties of hypertonic lactated saline solution in burn resuscitation, we have extended its use to acute hemorrhage. Using an awake canine model analogous to the clinical situation, we compared hypertonic lactated saline solution with Ringer's lactate solution for resuscitation in the presence of acute blood loss. The hypertonic lactated saline solution group required less fluid to restore and maintain cardiac output and blood pressure while maintaining better urine output. Although the Ringer's lactate solution group had increased shunt function indicative of pulmonary dysfunction, the shunt function in the hypertonic lactated saline solution group did not differ from that in the control group. Serum sodium and osmolality values were higher in the hypertonic lactated saline solution group, but at no time did they approach toxic levels.

Acute Disease↗
PubMed1985

Positron emission tomography: new analytic tool for vascular disease.

Positron emission tomography (PET) is a noninvasive technique that allows the quantification of regional physiologic and biochemical function in vivo. Biochemically active compounds, labeled with positron-emitting isotopes, are administered and the subsequent distribution of radioactivity measured. Although images are produced, they are of secondary importance to the ability to measure cellular metabolic function. The capability of PET to measure regional blood flow, oxygen, and substrate metabolism make it particularly useful in conditions of vascular compromise. Brain and heart have been studied extensively during normal function and while ischemic. PET is able to distinguish ischemic tissue from normal and reversibly from irreversibly injured tissue. PET has been used to document the need for and the metabolic response to vascular surgery. Although PET is complex and expensive, it may offer a means for establishing a more scientific basis for the therapy of vascular disease.

Animals↗
PubMed1985

Hypertonic lactated saline resuscitation of severely burned patients over 60 years of age.

Twenty-six adults more than 60 years old with burns greater than or equal to 30% of the body surface area were resuscitated using hypertonic lactated saline (HLS). Hemodynamic parameters of resuscitation were measured in ten of the patients using a Swan-Ganz catheter. In spite of signs of hemodynamic stability, these patients demonstrated mean cardiac indices (CI) below their age-corrected norms and pulmonary capillary wedge pressures (PCWP) below 5 mm Hg through 24 hours, yet 92% of the patients produced normal or super-normal volumes of urine. Hemodynamic monitoring may be helpful for precise fluid replacement in extensively burned elderly patients; however, a normal CI and PCWP may not be the appropriate endpoint for resuscitation of the elderly when using HLS. This review supports the concept that HLS resuscitation of critically burned older patients is both safe and efficacious, leading to an 81% survival of this severely compromised group well past the resuscitation phase of injury.

Age Factors↗
PubMed1984

In vivo time-resolved brain phosphorus nuclear magnetic resonance.

Methods used to obtain and quantify high-quality time-resolved dog brain phosphorus nuclear magnetic resonance (31P NMR) spectra are described. In eight animals the normoxic dog brain spectra showed 10% of total phosphorus in ATP, 14% in phosphocreatine (PCr), and 38% in brain phospholipids containing phosphodiesters. The chemical shift between PCr and inorganic phosphate, 5.09, corresponded to an intracellular brain pH of 7.2. During hypoxia, PCr declined to 0.5 +/- 0.3 (n = 8) of starting levels, prior to any changes in brain ATP. Simultaneous recording of the EEG was obtained in two animals. During hypoxia, progressive PCr depletion was associated with progressive slowing of the EEG, which was essentially silent before significant changes occurred in brain ATP. Finally, the brain 31P NMR spectrum and pH were measured at 90-s intervals, and the sequential changes that followed respiratory arrest were monitored in one dog until high-energy phosphate depletion was complete.

Adenosine Triphosphate↗
PubMed1982

The deleterious effects of high dose cimetidine in acute thermal injury.

Pharmacological doses of cimetidine have been reported to reduce oedema formation in murine burn models. Sprague-Dawley rats subjected to a 30 per cent full-thickness burn were treated with cimetidine (200 mg/kg) pre and post burn. Untreated, burned animals and sham-burned animals were also studied. No beneficial effects of cimetidine were demonstrated. Cimitidine increased the water content in lung, stomach and eschar of burned animals. No differences were seen in serum or urine electrolytes, or extrarenal water loss. Cimetidine did reduce serum hyperosmolality seen in unresuscitated burned animals. Multiple doses of cimetidine following thermal injury were associated with a significant increment in mortality rate.

Animals↗
PubMed1982

Cerebral edema following acute hemorrhage in a murine model: the role crystalloid resuscitation.

Unanesthetized male Sprague-Dawley rats were bled 40% of their blood volume. After 1 hour of hypovolemia, the animals were resuscitated with either lactated Ringer's solution (LRS) or hypertonic lactated saline (HLS). They received a volume of crystalloid equal to the shed blood volume or twice the shed blood volume. Twenty-four hours after resuscitation, the animals were sacrificed and the brains excised. The per cent water content was determined. Severe hemorrhage without resuscitation resulted in significantly increased intracerebral water content (77.7 +/- 1.0 vs 78.9 +/- 0.7 p less than 0.05). Resuscitation with twice the shed blood volume of either LRS or HLS prevented this increase in intracerebral water. These data support the conclusion that adequate resuscitation is the critical factor in preventing cerebral edema following acute severe hemorrhage.

Animals↗
PubMed1982

The effect of dopamine on postburn myocardial depression.

Myocardial performance is severely depressed following burns to more than 30% of the body surface area. Cardiac output in the immediate postburn period is dissociated from plasma volume. Many attempts have been made to improve early postburn hemodynamics with little success. Continuous infusion dopamine in low doses has recently been reported to improve at least one index of cardiac performance (LVSWI). We report the use of low-dose (5-10 mcg/kg X min) dopamine in the first 24 hours postburn in 20 seriously burned adults. Hemodynamic data are presented immediately preinfusion and after 1 hour of dopamine. Low-dose dopamine produced no change in cardiac index, arterial pressure, LVSWI, or any other hemodynamic parameter. We conclude that dopamine is of no benefit in treating the depressed myocardial function seen following major burns.

Adult↗
PubMed1981

A prospective analysis of silver sulfadiazine with and without cerium nitrate as a topical agent in the treatment of severely burned children.

Previous studies have indicated that combining cerium nitrate with silver sulfadiazine (Silvadene, Marion Labs) yields a superior topical agent for the treatment of burns. Cerium nitrate in silver sulfadiazine was tested in a controlled study with silver sulfadiazine alone. The study population consisted of two groups of children suffering burns greater than 30% of the body surface. The patients ranged in size from 1 to 21 years. The study period was for the first 10 weeks of hospitalization. Quantitative surface cultures were used to monitor burn wound flora. No superiority for the silver sulfadiazine-cerium nitrate combination was demonstrated. In fact, cultures indicate a significantly greater percentage of Gram-negative pathogens in patients treated with the cerium mixture. Cerium nitrate could possibly prove of greatest benefit if used as a reserve therapy for colonizing organisms which do not routinely respond to silver sulfadiazine.

Administration, Topical↗
PubMedDate not supplied

Toxic megacolon secondary to pseudomembranous colitis.

Toxic megacolon has rarely been reported in the course of antibiotic-induced pseudomembranous colitis. We have been able to collect 20 cases from the literature and add one new case. The mortality in the collected series was 33 per cent. The critical factor in improving survival is early recognition of the pseudomembranous colitis. Most patients can be managed medically by removal of the offending antibiotic, bowel rest, vancomycin, and steroids. If toxic megacolon develops in the face of appropriate medical management, an aggressive surgical approach is indicated, as with ulcerative colitis. Subtotal colectomy appears to be the procedure of choice.

Adult↗
PubMedDate not supplied

Alterations in plasma copper, zinc, and ceruloplasmin levels in patients with thermal trauma.

This review was undertaken to elucidate the trends in copper, zinc, total serum protein, and ceruloplasmin levels in patients with thermal trauma. Medical records of pediatric and adult patients were retrospectively reviewed. The findings showed a significant linear decline in mean plasma copper, ceruloplasmin, and total serum protein during the first three days postburn, followed in general by a gradual rise in levels; however, patients with burns larger than 60% TBSA maintained copper, zinc, and ceruloplasmin levels significantly below the lower limits of normal during the observation period. Significant decrements in copper, zinc, total serum protein, and ceruloplasmin levels have been demonstrated in these patients. Trace metal determinations should be obtained in patients with significant burns soon after admission and routinely throughout their hospital course. Specific trace metal supplementation should be administered when indicated.

Adult↗
PubMedDate not supplied

Energy balance studies and plasma catecholamine values for patients with healed burns.

We report heat balance studies and plasma catecholamine values for 49 children and young adults with healed burn wounds (age range 0.6 to 31 years and burn range 1% to 82% body surface area burned; mean 41%). All measurements were made during the week of discharge. Heat production for patients with healed burns was not significantly different from predicted normal values. However, compartmented heat loss demonstrated a persistent increment in evaporative heat loss that was secondary to continued elevation of cutaneous water vapor loss immediately after wound closure. A reciprocal decrement in dry heat loss was demonstrated (as a result of a cooler average surface temperature, 0.84 degree C cooler than the average integrated skin temperature of five normal volunteers who were studied in our unit under similar environmental conditions). Mean values for plasma catecholamines were in the normal range: epinephrine = 56 +/- 37 pg/ml, norepinephrine = 385 +/- 220 pg/ml, and dopamine = 34 +/- 29 pg/ml. In conclusion, patients with freshly healed burn wounds have normal rates of heat production; however, there is a residual increment in transcutaneous water vapor loss, which produces surface cooling and decreased average surface temperature, which in turn lowers dry heat loss by an approximately equivalent amount.

Adolescent↗
PubMedDate not supplied

Absence of postburn hypermetabolism in a group of children with serious burns.

Hypermetabolism proportional to wound size is the expected response in patients who sustain large burns. This metabolic response persists until wound closure is achieved. The value of this response to the injured host remains unproven. Between 1978 and 1991, 104 patients with burns covering 30% or more of the body surface area underwent partitional calorimetry as a component of various research protocols. Thirteen of these patients failed to demonstrate an increase in metabolic rate as compared with a control group. These patients without hypermetabolism were compared with case-matched patients who demonstrated the expected increase in metabolic rate. Although they were not hypermetabolic in response to the burn injury, five of these patients were exposed to a cold stress and were able to increase their metabolic rate appropriately. The failure to mount a hypermetabolic response did not impact the clinical course as measured by survival, length of hospital stay, or maximum weight loss.

Body Surface Area↗
PubMedDate not supplied

Alteration in gastrointestinal peptides after thermal injury in humans.

Alterations in gastrointestinal function are common after thermal injury in humans. The peptide hormones gastrin and cholecystokinin are known to exert effects on gastric and biliary motility and on secretory function and to induce trophic changes in gut mucosa. The effect of injury on these hormones has received little attention. Six patients with burns were studied while receiving a combination of regular diet and continuous enteral feeding. Four healthy members of the nursing staff served as the control group. Blood was drawn every 4 hours for 24 hours. Gastrin and cholecystokinin were analyzed by radioimmunoassay. Patients with burns demonstrated significantly higher levels of gastrin and lower levels of cholecystokinin when compared with the control group. Patients with burns also failed to demonstrate the normal circadian variation in these peptides.

Adult↗