Hand dominance and performance in a laparoscopic skills curriculum

BACKGROUND

This study evaluated the influence of hand dominance on skill acquisition during a basic laparoscopic skills curriculum.

METHODS

A total of 27 surgical residents (5 postgraduate year 3 [PGY-3] and 22 PGY-2 residents) participated in a 4-week laparoscopic skills curriculum. The residents were pre- and posttested on six laparoscopic tasks during weeks 1 and 4. During weeks 2 and 3, the residents attended a proctored practice session. The results were compared using analysis of variance (ANOVA), (with significance determined by a p value less than 0.05.

RESULTS

The posttest scores were significantly higher than the pretest scores. On the pretest, lefthand-dominant (LHD) surgeons (n = 4) performed significantly better than righthand-dominant (RHD) surgeons (n = 23). In the analysis of individual task pretest scores, LHD surgeons performed significantly better on pattern cutting and vessel loop application. Posttest analysis of overall performance did not show significant differences between the RHD and LHD surgeons.

CONCLUSIONS

Participation in a laparoscopic skills curriculum improved overall performance. The LHD surgeons demonstrated better initial performance, but posttest comparison showed no difference between the two groups.

Endoscopic measurement of pancreatic tissue perfusion in patients with chronic pancreatitis and control patients

BACKGROUND

Pancreatic blood flow is diminished in experimental models of acute and chronic pancreatitis. We attempted to develop a safe and reliable technique for its measurement in patients and to examine blood flow in patients with chronic pancreatitis and in control subjects.

METHOD

Pancreatic blood flow was measured using the hydrogen gas clearance technique and an endoscopically placed platinum ductal electrode. Pancreatic blood flow was measured in 12 patients with chronic pancreatitis diagnosed clinically and radiographically, and in 11 control patients undergoing endoscopic retrograde cholangiopancreatography (ERCP) for non-pancreatic pathology.

RESULTS

Patients with chronic pancreatitis had a significantly lower pancreatic blood flow compared with control patients (51.5 versus 91.7 mL/min/100 gm, p < 0.01). With secretin stimulation pancreatic blood flow increased in two control patients, whereas this notable rise was not seen in three patients with chronic pancreatitis.

CONCLUSIONS

Measurement of pancreatic blood flow with an endoscopically placed electrode is relatively safe and simple to perform. The scarring and vascular fibrosis associated histologically with chronic pancreatitis is reflected in lower pancreatic blood flow.

Effect of pancreaticojejunostomy on fibrosis, pancreatic blood flow, and interstitial pH in chronic pancreatitis: a feline model

OBJECTIVE

To study the relation between fibrosis, pancreatic blood flow (PMBF), interstitial pH (pHi), and the effects of pancreaticojejunostomy (PJ) in chronic pancreatitis.

BACKGROUND

Chronic pancreatitis is associated with low PMBF and pHi, suggesting the existence of underlying ischemia.

METHODS

In cats, the main pancreatic duct was partially obstructed and the animals were studied 2, 4, 6, and 8 weeks later. PJ was performed after 2 and 4 weeks of ductal obstruction and studied 4 weeks later. PMBF and pH were measured before and after stimulation with secretin and cholecystokinin. pHi was measured with microelectrodes, PMBF by hydrogen gas clearance. Histologic analysis of the pancreas with Sirius red (collagen stain) and fast green FCF (noncollagen protein) stains allowed semiquantitative analysis of the ratio between collagen and total protein (C/TP).

RESULTS

With the evolution of chronic pancreatitis, there is a progressive increase in the collagen content and C/TP ratio, a reduction in basal PMBF and pHi, and loss of the normal response to stimulation. Early PJ restores collagen content, C/TP ratio, and basal and stimulated PMBF and pHi to normal. PJ performed in established CP returns the C/TP ratio to normal, improves basal PMBF, and restores the normal hyperemic response to secretion. Basal pHi is improved and the "acid tide" associated with secretin returns, but there is still no response to cholecystokinin.

CONCLUSIONS

Pancreaticojejunostomy restores the elevated collagen and C/TP ratio to normal and reverses the ischemia present in CP. The authors speculate that restoration of PMBF and its normal response to stimulation allows "regeneration" and restoration of secretory function.

Feline model of chronic obstructive pancreatitis: effects of acute pancreatic duct decompression on blood flow and interstitial pH

BACKGROUND

The mechanism by which duct decompression (DD) relieves pain in patients with chronic pancreatitis (CP) is unknown. CP is associated with increased tissue pressure (IP), low pancreatic microvascular blood flow (PMBF), and interstitial pH (pH(I)). The aims of this study were to examine the effects of acute DD on PMBF, increased IP, and pH(I) in cats with CP.

METHODS

The main pancreatic duct was partially obstructed. At 6 weeks PMBF (ml/min/100g H2 gas clearance), IP (mmHg needle electrode), and pH(I) (microelectrode) were measured before and after secretin stimulation. The duct was then opened, and the studies were repeated.

RESULTS

PMBF normally increased with secretin stimulation (118 +/- 20 versus 271 +/- 52, P < 0.05). IP was unaltered, and pH(I) decreased as hydrogen ions produced during bicarbonate secretion were dissipated (7.41 +/- 0.01 versus 7.38 +/- 0.01, P < 0.05). In CP, basal PMBF was lower than normal (51 +/- 6 versus 118 +/- 20, P < 0.05) and decreased with stimulation (51 +/- 3.5 versus 31 +/- 3.5, P < 0.05). Basal pancreatic IP was increased (3.47 +/- 0.7 versus 0.05 +/- 0.3, P < 0.05) and increased further with secretory stimulation (3.47 +/- 0.7 versus 4.41 +/- 0.7, P < 0.05) (a compartment syndrome). The low basal pancreatic pH(I) (7.23 +/- 0.02) did not change with secretin stimulation, since bicarbonate secretion was minimal. DD decreased IP (3.66 +/- 0.5 versus 2.81 +/- 0.5, P < 0.05) and increased PMBF (50 +/- 6 versus 79 +/- 6, P < 0.05) and pH(I) (7.24 +/- 0.02 versus 7.34 +/- 0.02, P < 0.05). The normal increase in PMBF after stimulation was restored (79 +/- 6 versus 218 +/- 54, P < 0.05). pH(I) now increased with stimulation (7.34 +/- 0.002 versus 7.37 +/- 0.002, P < 0.05), perhaps due to the marked hyperaemic response.

CONCLUSIONS

DD acutely restored basal and stimulated PMBF and IP towards normal. Basal pancreatic pH(I) also improved and reflects the underlying ischaemia.

Intragastric alcohol causes endothelin release from feline pancreas

The mechanism by which alcohol causes pancreatic damage is still largely unknown. One important contributory factor may be the endothelins, potent vasoconstricting endothelial-derived peptides. The aim of this study was to examine in vivo endothelin release from the pancreatic vascular endothelium after alcohol ingestion. In anesthetized cats immunoreactive endothelin was measured in serum after instillation of alcohol into the stomach (20 ml, 40%). After intragastric alcohol, a rise in endothelin was seen in pancreatic venous effluent (to a mean of 24.5 +/- 7.7 pg/ml at 60 min). Control serum from the femoral artery exhibited no rise in endothelin (2.11 +/- 1.2 pg/ml). Pancreatic blood flow was significantly decreased in a further group to 93% basal after intravenous infusion of 0.1 nmol/kg ET-1 and to 61% after infusion of 1 nmol/kg ET-1. Portal serum levels of endothelin were 105 pg/ml and 15 pg/ml, respectively, immediately following bolus infusion and decreased to normal levels within 120 sec. We conclude that the serum endothelin rise after intragastric ethanol may be a major factor behind the drop in pancreatic blood flow.

Effect of ethanol on pancreatic interstitial pH and blood flow in cats with chronic pancreatitis

OBJECTIVE

The objective of this study was to investigate the effects of ethanol on pancreatic blood flow and interstitial pH in chronic pancreatitis.

BACKGROUND

Ethanol is known to contribute to the development of both acute and chronic pancreatitis. However, it is unclear how ethanol precipitates episodes of acute pancreatic inflammation in the setting of chronic pancreatitis. In a model of chronic pancreatitis in cats, it is known that pancreatic blood flow is abnormally low and decreases further after ethanol ingestion. Because it is possible that this reduction in blood flow might be damaging to the pancreas, we investigated the effects of ethanol on pancreatic interstitial pH, an index of pancreatic ischemia.

METHODS

In normal cats and cats with obstructive chronic pancreatitis, pancreatic blood flow and interstitial pH were measured using the hydrogen gas clearance technique and pH microelectrode, respectively.

RESULTS

In normal cats, intragastric, but not intravenous, ethanol reduced both pancreatic blood flow by 62% (p < 0.05) and interstitial pH (7.38 +/- 0.03 to 7.20 +/- 0.03, p < 0.05). In cats with chronic pancreatitis in which basal pancreatic blood flow was already only 60% of normal flow, both intragastric and intravenous ethanol decreased both pancreatic blood flow (intragastric, 40% decrease, p < 0.05; intravenous, 34% decrease, p < 0.05) and interstitial pH (intragastric, 7.24 +/- 0.04 to 7.08 +/- 0.04, p < 0.05; intravenous 7.20 +/- 0.08 to 7.07 +/- 0.07, p < 0.05).

CONCLUSIONS

This profound decrease in pH, lasting up to 2 hours after ethanol exposure in the chronic pancreatitis animals, suggests the possibility of ischemic cellular damage to the pancreas. These findings may explain the pathogenesis of bouts of acute pancreatic inflammation after ethanol ingestion in the setting of chronic disease.

Ischaemia-reperfusion mechanisms in acute pancreatitis

The role of ischaemia in the pathogenesis of acute pancreatitis is unknown. Some experimental studies have shown that ischaemia has little effect on the pancreas, while others have found an association with pancreatic injury. Ischaemia-reperfusion damage has been well documented in other sites such as the intestine, cardiac muscle, and skeletal muscle. However, in the pancreas, injury is usually seen only after complete ischaemia, which is uncommon clinically. Experimental chronic pancreatitis is characterized by low pancreatic blood flow, low interstitial pH, and impaired pancreatic tissue oxygenation, which are all findings consistent with the ischaemia-reperfusion mechanisms. Acute pancreatitis is also associated with a reduction in pancreatic blood flow and evidence of free radical generation, similarly suggesting the possibility of ischaemia-reperfusion injury. Ethanol ingestion, which is commonly associated clinically with both chronic and acute pancreatitis, may itself contribute to an ischaemic-reperfusion injury. We have shown that administration of ethanol to cats decreases pancreatic blood flow and may also directly activate neutrophils. Further investigation is needed to determine whether or not these findings are also associated with an ischaemia-reperfusion injury.

Pancreatic interstitial pH in human and feline chronic pancreatitis

BACKGROUND & AIMS

Advanced chronic pancreatitis is associated with a reduction in pancreatic blood flow. To determine the physiological significance of this decrease, pancreatic interstitial pH was measured in a model of obstructive chronic pancreatitis in cats and in patients with chronic pancreatitis.

METHODS

In cats, pancreatic interstitial pH and blood flow were measured serially under basal conditions and after secretory stimulation as chronic pancreatitis evolved. Basal pancreatic interstitial pH was also measured in patients undergoing an operation for chronic pancreatitis or periampullary cancer (controls).

RESULTS

In normal cats, pancreatic interstitial pH was 7.41 +/- 0.01 and blood flow was 124 mL.min-1.(100 g pancreas-1). With the evolution of chronic pancreatitis, interstitial pH and blood flow progressively decreased to 7.21 +/- 0.04 (P < 0.007) and 75 +/- 11 (P < 0.007), respectively. From 1 to 2 weeks, secretory stimulation reduced pancreatic interstitial pH and blood flow further, but as secretory function was lost, this effect disappeared. In patients with chronic pancreatitis, the interstitial pH was lower (7.02 +/- 0.06) than in controls (7.25 +/- 0.04; P < 0.05).

CONCLUSIONS

These observations are consistent with the hypothesis that, in chronic pancreatitis, acidic metabolites associated with pancreatic secretion accumulate within the pancreas, probably because of impaired blood flow.

Pylorus-preserving Whipple resection for pancreatic cancer. Is it any better?

OBJECTIVE

To compare the short- and long-term morbidity and mortality rates of the standard Whipple pancreatoduodenectomy (SW) and its pylorus-preserving modification (PPW) in patients with malignant periampullary disease.

DESIGN

Retrospective medical record review and quality of life assessment by telephone interview.

SETTING

University medical center.

STUDY PARTICIPANTS

Sixty-seven patients who underwent pancreatoduodenectomy (52 SW and 15 PPW) from June 1988 to January 1994.

INTERVENTION

The SW and PPW.

MAIN OUTCOME MEASURES

Operative features and short- and long-term complications were analyzed with respect to the type and stage of cancer and the kind of pancreatic resection. Mean follow-up was 32 months (range, 1 to 5 years).

RESULTS

The operative mortality rate for all patients who had a pancreatic resection was 1.5%. The diagnoses in the PPW vs SW groups were pancreatic cancer (four vs 27 patients), ampullary cancer (six vs seven patients), duodenal cancer (zero vs six patients), and bile duct cancer (five vs one patient). Operative mortality rates (0% vs 1.55%) and operative times (2 minutes longer for SW) were similar. Delayed gastric emptying (61% vs 41%) was more common in the PPW group, resulting in a longer hospitalization (24 vs 18 days) and a greater cost in the PPW group (P = .04). In the PPW group, a mean of five lymph nodes was removed compared with 10 in the SW group (P = .04).

CONCLUSIONS

The data provided no evidence of any advantage for the PPW in patients with malignant periampullary tumors. We continue to advocate the SW for pancreatic cancer.

Role of nitric oxide in the relationship of pancreatic blood flow and exocrine secretion in cats

BACKGROUND/AIMS

Recent studies have suggested that, in the gastrointestinal tract, nitric oxide is an important mediator of alterations in blood flow and, in some organs, a second messenger involved in secretion. This study examined the role of NO in changes in pancreatic blood flow associated with basal and stimulated pancreatic exocrine secretion.

METHODS

In anesthetized cats, we determined the effects of the NO synthase inhibitor NG-monomethyl-L-arginine (10 mg/kg) and the NO donor sodium nitroprusside (10 micrograms.kg-1.min-1) on pancreatic secretion and blood flow (hydrogen gas clearance).

RESULTS

NG-monomethyl-L-arginine had no effect on the increase in blood flow associated with secretin stimulation (271 +/- 52 vs. 290 +/- 50 mL.min-1.100 g-1) but reduced that associated with cholecystokinin stimulation (189 +/- 17 vs. 53 +/- 15 mL.min-1.100 g-1; P < 0.001). In contrast, NG-monomethyl-L-arginine significantly reduced both secretin- and cholecystokinin-stimulated secretion. Sodium nitroprusside had no effect on basal blood flow but significantly increased secretion.

CONCLUSIONS

NO has a selective role in mediating changes in pancreatic perfusion and secretion. It seems to be important in stimulus-secretion coupling with both secretin and cholecystokinin but is only responsible for the accompanying increase in pancreatic blood flow with cholecystokinin.