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Biomedical subjects

F N Hamilton

Publications and source records attributed to F N Hamilton.

13 recordsLinked to original sources
PubMed1990

Study of surgical resident working hours and time utilization.

Recently, changes have been suggested in resident working hours and conditions. Few objective data exist, however, as to how many hours surgical residents work or how they utilize their time. Surgical residents on four every-third-night general surgery services (two services in the University Hospital and two in the Veterans Hospital) kept a log of their activities divided into 15-min intervals 24 hr a day for 4 weeks. Activity for each 15-min interval was entered into one of nine predesignated categories. Residents spent an average of 95.8 hr per week in the hospital, working 85.8 hr and sleeping 10 hr. Overall, residents slept an average of 5.9 hr per night, 4.2 hr on on-call nights and 6.2 hr on off-call nights. Operating and direct patient care activities consumed 8.7 hr per day (10.25 hr Monday to Friday). Patient care activities which residents believed could be performed by nonphysicians accounted for 1.5 hr per day. An average of 1.8 hr per day was spent in conferences or independent study. This survey provided objective data regarding working hours and time utilization for our residency. Both residents and faculty found that time spent in various activities differed from preconceived notions. We suggest that program directors may find a formal survey of this type useful in assessing the structure of their own residency and in providing objective data to compare to or determine compliance with externally generated guidelines.

General Surgery↗
PubMed1987

Early total parenteral nutrition in acute pancreatitis: lack of beneficial effects.

To determine the effect of early aggressive parenteral support in pancreatitis, 54 patients with acute pancreatitis were randomized to receive either conventional therapy (control group) or conventional therapy plus the institution of total parenteral nutrition within 24 hours. The two groups were similar demographically. The total parenteral nutrition group had a significantly higher rate of catheter-related sepsis than did an additional group of contemporaneous patients without pancreatitis who received total parental nutrition (10.5 percent and 1.47 percent, respectively; p less than 0.01). There was no advantage to the use of early total parenteral nutrition; that is, there was no difference in the number of days to oral intake, total hospital stay, or number of complications of pancreatitis. Patients with zero or one Ranson's criterion on admission were more likely to be eating by the seventh hospital day than were those with two or more Ranson's criteria (80 percent and 54 percent, respectively; p less than 0.05). The early institution of total parenteral nutrition in patients with acute pancreatitis did not appear to improve the outcome. Its use should be limited to prolonged periods of no oral intake or treatment of a specific complication, such as a pseudocyst.

Acute Disease↗
PubMed1987

The value of hepatobiliary scans in fasted patients receiving total parenteral nutrition.

Hepatobiliary scanning is considered to be a highly accurate method for the diagnosis of acute cholecystitis. False-positive scans (failure to visualize the gallbladder in the absence of cholecystitis) have been reported to occur in fasted patients receiving total parenteral nutrition (TPN). To determine the prevalence of false-positive scans in this patient population and identify factors that might be associated with scan outcome, hepatobiliary imaging was performed in fasted patients receiving TPN and without clinical evidence of acute cholecystitis. Gallbladder nonvisualization occurred in 18 of 50 (36%) patients. In the group whose gallbladders did not visualize, a significantly higher male to female ratio (15:3 versus 17:15; p = 0.016), alkaline phosphatase (346 +/- 84 IU/L versus 212 +/- 32 IU/L, p less than 0.04), total bilirubin (1.7 +/- 0.3 mg/dl versus 1.0 +/- 0.2 mg/dl, p less than 0.02), and lower serum albumin (2.4 +/- 0.01 gm/dl versus 2.8 +/- 0.2 gm/dl, p less than 0.02) levels were noted. In 18 patients, gallbladder ultrasonography was also performed, and the presence of sludge or a thickened gallbladder wall did not correlate with scan outcome. The prevalence of false-positive hepatobiliary scans in fasted patients receiving TPN is significant and does not always correlate with a syndrome of acute gallbladder inflammation. The results of such scans must therefore be interpreted with caution in these patients.

Adult↗
PubMed1976

Coronary vascular sympathetic beta-receptor innervation.

Recent studies indicate that coronary vessels have alpha- and beta-2-adrenergic receptors and that the alpha receptors are functionally innervated. We studied whether the beta-2-vasodilator receptors are functionally innervated, using a dog in situ modified Langendorff preparation with constant coronary perfusion pressure. The beating, nonworking heart and systemic circulation were supported with a pump oxygenator. Stimulation of the left stellate ganglion increased coronary blood flow and decreased coronary sinus oxygen tension from prestimulation control values. After beta-1-receptor blockade (practolol, 10 mg/kg), stellate stimulation decreased coronary blood flow and decreased coronary sinus oxygen tension from prestimulation control values, revealing alpha-receptor vasoconstriction. After the addition of alpha-receptor blockade (Dibozane, 5 mg/kg), stellate stimulation increased coronary blood flow and coronary sinus oxygen tension a small amount from prestimulation values. Finally, after the addition of beta-2-receptor blockade (propranolol, 2 mg/kg), stellate stimulation increased flow and coronary sinus oxygen tension slightly from prestimulation control values. Direct intracoronary injections of isoproterenol, norepinephrine, and epinephrine gave results consistent with the presence of beta-1 myocardial receptors and alpha and beta-2 coronary receptors. We conclude that there is little functional innervation of coronary vascular beta-2 receptors. Intracoronary injections of isoproterenol and epinephrine activated beta-2-receptor coronary vasodilation after beta-1-receptor blockade, but norepinephrine did not.

Adrenergic alpha-Antagonists↗
PubMed1969

Carbonic acid production and the role of carbonic anhydrase in decarboxylation in brain.

Sudden oxygenation of a thin film of rat brain homogenate, suspended between the surface of a glass pH-sensitive electrode and a gas-permeable membrane, is accompanied by a fall in pH, which is greater when carbonic anhydrase is inhibited. The result suggests that oxidative decarboxylation yields carbonic acid (HCO(3)- and H(+)), which dissociates to form molecular carbon dioxide. Brain carbonic anhydrase facilitates the formation of carbon dioxide from the decarboxylation products.

Acetazolamide↗