Vasopressor hormone response following mesenteric traction during major abdominal surgery

Laser Speckle Contrast Imaging-based diagnosis of severe mesenteric traction syndrome: Hemodynamics and prostacyclin - A prospective cohort study

BRIEF ABSTRACT

Today, the diagnosis and grading of mesenteric traction syndrome relies on a subjective assessment of facial flushing. However, this method has several limitations. In this study, Laser Speckle Contrast Imaging and a predefined cut-off value are assessed and validated for the objective identification of severe mesenteric traction syndrome.

BACKGROUND

Severe mesenteric traction syndrome (MTS) is associated with increased postoperative morbidity. The diagnosis is based on an assessment of the developed facial flushing. Today this is performed subjectively, as no objective method exists. One possible objective method is Laser Speckle Contrast Imaging (LSCI), which has been used to show significantly higher facial skin blood flow in patients developing severe MTS. Using these data, a cut-off value has been identified. This study aimed to validate our predefined LSCI cut-off value for identifying severe MTS.

METHODS

A prospective cohort study was performed on patients planned for open esophagectomy or pancreatic surgery from March 2021 to April 2022. All patients underwent continuous measurement of forehead skin blood flow using LSCI during the first hour of surgery. Using the predefined cut-off value, the severity of MTS was graded. In addition, blood samples for prostacyclin (PGI₂) analysis and hemodynamics were collected at predefined time points to validate the cut-off value.

MAIN RESULTS

Sixty patients were included in the study. Using our predefined LSCI cut-off value, 21 (35 %) patients were identified as developing severe MTS. These patients were found to have higher concentrations of 6-Keto-PGF_aα (p = 0.002), lower SVR (p < 0.001), lower MAP (p = 0.004), and higher CO (p < 0.001) 15 min into surgery, as compared with patients not developing severe MTS.

CONCLUSION

This study validated our LSCI cut-off value for the objective identification of severe MTS patients as this group developed increased concentrations of PGI₂ and more pronounced hemodynamic alterations compared with patients not developing severe MTS.

Mesenteric traction syndrome - Incidence, impact, and treatment: A systematic scoping review of the literature

BACKGROUND

Mesenteric traction syndrome (MTS) is commonly seen during major abdominal surgery and is characterised by facial flushing, hypotension, and tachycardia 15 min into surgery. MTS also impacts the postoperative course, as severe MTS has been associated with increased postoperative morbidity. However, despite MTS being common and severe MTS causing increased postoperative morbidity, the gaps in the literature are not clearly defined. We aimed to examine the diagnostic criteria, incidence, intraoperative and postoperative impact, and potential preventative measures of MTS while highlighting potential gaps in the literature.

METHODS

We followed the Prisma guidelines and performed a systematic literature search. We included only human studies examining MTS. All hits were screened for title and abstract, followed by a full-text review by at least two authors for determining eligibility for inclusion. Data were extracted and risk of bias was assessed by two independent reviewers.

RESULTS

A total of 37 studies, comprising 1102 patients were included in the review. The combined incidence of MTS during open abdominal surgery was found to be 76%, with 35% developing severe MTS. It was found that the development of MTS was associated with marked haemodynamic changes. It was also found that several different subjective diagnostic criteria exist and that severe MTS was associated with increased postoperative morbidity. Furthermore, several preventative measures for protecting against MTS have been examined, but only on the incidence of MTS and not on the postoperative course.

CONCLUSION

MTS occurs in 76% of patients undergoing major abdominal surgery and is associated with deleterious haemodynamic effects, which are more pronounced in patients developing severe MTS. Severe MTS is also associated with a worse postoperative outcome. However, gaps are still present in the current literature on MTS.

Mesenteric traction syndrome in pigs: A single-blinded, randomized controlled trial

Background

Mesenteric traction syndrome is commonly observed in patients undergoing upper abdominal surgery and is associated with severe postoperative complications. A triad of hypotension, tachycardia, and facial flushing seems provoked by prostacyclin (PGI2) release from the gut in response to mesenteric traction. The administration of nonsteroidal anti-inflammatory drugs (NSAID) inhibits PGI2 release, stabilizing the hemodynamic response. Here, we examined the effect of mesenteric traction on splanchnic blood flow in pigs randomized to NSAID or placebo treatment.

Materials and Methods

Twenty pigs were allocated to either ketorolac or placebo treatment. Five minutes of manual mesenteric traction was applied. Plasma 6-keto-PGF1α, a stable metabolite of PGI2, hemodynamic variables, and regional blood flow (laser speckle contrast imaging) to the liver, stomach, small intestine, upper lip, and snout (laser Doppler flowmetry) were recorded prior to traction and 5 and 30 minutes thereafter.

Results

Both groups of pigs presented a decrease in systemic vascular resistance (P = .01), mean arterial blood pressure (P = .001), and blood flow in the gastric antrum (P = .002). Plasma 6-keto-PGF1α did not increase in either group (P = .195), and cardiac output, heart rate, central venous pressure, and blood flow to the liver, small intestine, upper lip, and snout remained unchanged.

Conclusion

Mesenteric traction resulted in cardiovascular depression, including reduced blood flow in the gastric antrum. Plasma 6-keto-PGF1α did not increase, and ketorolac administration did not alter the response to mesenteric traction. Furthers studies are needed to identify which substance is responsible for eliciting the cardiovascular response to mesenteric traction in pigs.

Severe mesenteric traction syndrome is associated with increased systemic inflammatory response, endothelial dysfunction, and major postoperative morbidity

This study aimed to determine if mesenteric traction syndrome (MTS) triggers increased systemic inflammation and endothelial cell dysfunction. Patients developing severe MTS had pronounced early IL6 elevations followed by endothelial cell damage. Furthermore, these processes were associated with increased postoperative morbidity.

OBJECTIVE

To determine whether mesenteric traction syndrome (MTS) leads to increased systemic inflammation and dysfunction of the glycocalyx and endothelial cell and whether this correlates with the degree of postoperative morbidity.

INTRODUCTION

Severe MTS is associated with increased postoperative morbidity following major gastrointestinal surgery, but the pathophysiological mechanism has not been previously explored. Systemic inflammatory response and impaired glycocalyx and endothelial cells may be responsible for the development of symptoms.

METHODS

The study analyzed prospectively collected data from two cohorts (n = 67). The severity of the MTS response was graded intraoperatively and blood samples for PGI₂, catecholamines, IL6, and endothelial biomarkers obtained at predefined time points.

RESULTS

Patients undergoing either esophagectomy (n = 45) or gastrectomy (n = 22) were included. Surgery led to significantly increased plasma concentrations of all biomarkers. Yet, patients who developed severe MTS had higher baseline epinephrine levels (p < 0.05) and higher levels of PGI₂ (p < 0.05), Syndecan-1 (p < 0.001), and sVEGFR1 (p < 0.001). Peak values of IL6, Syndecan-1, sVEGFR1, and sTM all correlated to peak PGI₂. Lastly, patients with high postoperative morbidity had higher baseline epinephrine (p = 0.009) and developed higher plasma IL6 (p = 0.007) and sTM (p = 0.022).

CONCLUSION

The development of severe MTS during upper gastrointestinal surgery is associated with preoperative elevated plasma epinephrine and further a more pronounced proinflammatory response and damage to the vascular endothelium. The increased postoperative morbidity seen in patients with severe MTS may thus, in part, be explained by an inherent susceptibility towards an inappropriate secretion of PGI₂, which leads to an increased surgical stress response and endothelial damage. These findings must be confirmed in a new prospective cohort.

Hypotension Associated with MTS is Aggravated by Early Activation of TEA During Open Esophagectomy

Objective

A mesenteric traction syndrome (MTS) is elicited by prostacyclin (PGI₂)-induced vasodilation and identified by facial flushing, tachycardia, and hypotension during abdominal surgery. We evaluated whether thoracic epidural anesthesia (TEA) influences the incidence of MTS.

Design

Randomized, blinded controlled trial.

Setting

Single-center university hospital.

Participants

Fifty patients undergoing open esophagectomy.

Interventions

Patients were randomized to either early (EA, after induction of general anesthesia) or late activation of TEA (LA, after re-established gastric continuity). Plasma 6-keto-PGF_1α, a stable metabolite of PGI₂ and interleukine-6 (IL6) were measured in plasma during surgery along with hemodynamic variables and MTS graded according to facial flushing together with plasma C-reactive protein on the third post-operative day.

Results

Forty-five patients met the inclusion criteria. Development of MTS tended to be more prevalent with EA (n=13/25 [52%]) than with LA TEA (n=5/20 [25%], p=0.08). For patients who developed MTS, there was a transient increase in plasma 6-keto-PGF_1α by 15 min of surgery and plasma IL6 (p<0.001) as C-reactive protein (P<0.009) increased. EA TEA influenced the amount of phenylephrine needed to maintain mean arterial pressure >60 mmHg in patients who developed MTS (0.16 [0.016–0.019] mg/min vs MTS and LA TEA 0.000 [0.000–0.005] mg/min, p<0.001).

Conclusion

The incidence of MTS is not prevented by TEA in patients undergoing open esophagectomy. On the contrary, the risk of hypotension is increased in patients exposed to TEA during surgery, and the results suggest that it is advantageous to delay activation of TEA. Also, MTS seems to be associated with a systemic inflammatory response, maybe explaining the aggravated post-operative outcome.

Quantitative fluorescence angiography detects dynamic changes in gastric perfusion

INTRODUCTION

The use of Indocyanine green (ICG) fluorescence angiography (ICG-FA) is an applied method to assess visceral perfusion during surgical procedures worldwide. Further development has entailed quantification of the fluorescence signal; however, whether quantified ICG-FA can detect intraoperative changes in perfusion after hemorrhage has not been investigated previously. In this study, we investigated whether a quantification method, developed and validated in our department (q-ICG), could detect changes in gastric perfusion induced by hemorrhage and resuscitation.

METHODS

Ten pigs were included in the study. Specific regions of interest of the stomach were chosen, and three q-ICG measurements of gastric perfusion obtained: 20 min after completion of the laparoscopic setup (baseline), after reducing the circulating blood volume by 30%, and after reinfusion of the withdrawn blood volume. Hemodynamic variables were recorded, and blood samples were collected every 10 min during the procedure.

RESULTS

The reduction in blood volume generated decreased gastric perfusion (q-ICG) from baseline (p = 0.023), and gastric perfusion subsequently increased (p < 0.001) after the reintroduction of the withdrawn blood volume. Cardiac output (CO) and mean arterial blood pressure (MAP) shifted correspondingly and the gastric perfusion correlated to CO (r = 0.575, p = 0.001) and MAP (r = 0.436, p = 0.018).

CONCLUSION

We present a novel study showing that the q-ICG method can detect dynamic changes in local tissue perfusion induced by hemorrhage and resuscitation. As regional gastrointestinal perfusion may be significantly reduced, while hemodynamic variables such as MAP or heart rate remain stable, q-ICG may provide an objective, non-invasive method for detecting regional early ischemia, strengthening surgical decision making.

Dexmedetomidine aggravates hypotension following mesenteric traction during total gastrectomy: a randomized controlled trial

BACKGROUND

Mesenteric traction syndrome (MTS), which is characterized by arterial hypotension and tachycardia following mesenteric traction (MT), frequently occurs during abdominal surgery. Dexmedetomidine, commonly used in general anesthesia during major surgery, has a sympatholytic effect and attenuates the compensatory response to hypotension.

OBJECTIVE

Assess the effect of dexmedetomidine on hypotension following mesenteric traction.

DESIGN

Prospective, randomized, controlled clinical trial.

SETTING

Department of Anesthesiology, Zhenjiang First People's Hospital in China.

PATIENTS AND METHODS

Patients were randomly divided into three groups. Dexmedetomidine, 0.5 or 1.0 µg/kg, was intravenously administered over 15 minutes before skin incision followed by a maintenance rate of 0.5 µg/kg/h in groups D1 and D2, respectively; saline was administered in group C.

MAIN OUTCOME MEASURE(S)

The duration of hypotension, heart rate and plasma norepinephrine level in patients with MTS were recorded within 60 minutes following MT.

SAMPLE SIZE

75 patients.

RESULTS

The duration of hypotension in the MTS patients in group D1 and D2 was significantly longer than that in groups C (D1 vs. C, P<.05; D2 vs. C, P<.01). Significantly more phenylephrine was required to treat hypotension in group D1 and D2 than was required for patients in group C (P<.05). The increase in heart rate during the first 15 minutes of MT in group D2 was significantly attenuated compared to that in group C (P<.0083). The increases in norepinephrine levels during the first 15 minutes of MT in group C were significantly higher than those in groups D1 and D2 (P<.0167).

CONCLUSION

Adjunctive dexmedetomidine in general anesthesia aggravates hypotension during MTS in open total gastrectomy.

LIMITATIONS

Postoperative complications were not evaluated.

CONFLICT OF INTEREST

None.

Development of a severe mesenteric traction syndrome during major abdominal surgery is associated with increased postoperative morbidity: Secondary data analysis on prospective cohorts

PURPOSE

MTS is elicited during open abdominal surgery and is characterized by facial flushing, hypotension, and tachycardia in response to the release of prostacyclin (PGI₂) to plasma. MTS seems to affect postoperative morbidity, but data from larger cohorts are lacking. We aimed to determine the impact of severe mesenteric traction syndrome (MTS) on postoperative morbidity in patients undergoing open upper gastrointestinal surgery.

METHODS

The study was a secondary analysis of data from three cohorts (n = 137). The patients were graded for severity of MTS intraoperatively, and hemodynamic variables and blood samples for plasma 6-keto-PGF_1α, a stable metabolite of PGI₂, were obtained at defined time points. Postoperative morbidity was evaluated by the comprehensive complication index (CCI) and the Dindo-Clavien classification (DC).

RESULTS

Patients undergoing either esophagectomy (n = 70), gastrectomy (n = 22), liver- (n = 23), or pancreatic resection (n = 22) were included. Severe MTS was significantly associated with increased postoperative morbidity, i.e., CCI ≥ 26.2 (OR 3.06 [95% CI 1.1-6.6]; p = 0.03) and risk of severe complications, i.e., DC ≥3b (OR 3.1 [95% CI 1.2-8.2]; p = 0.023). Furthermore, patients with severe MTS had increased length of stay (OR 10.1 [95% CI 1.9-54.3]; p = 0.007) and were more likely to be admitted to the intensive care unit (OR = 7.3 [95% CI 1.3-41.9]; p = 0.027), but there was no difference in 1-year mortality.

CONCLUSION

Occurrence of severe MTS during upper gastrointestinal surgery is associated with increased postoperative morbidity as indicated by an increased rate of severe complications, length of stay, and admission to the ICU. It remains to be determined whether inhibition of MTS enhances postoperative recovery.

Laser speckle contrast imaging for quantitative assessment of facial flushing during mesenteric traction syndrome in upper gastrointestinal surgery

The mesenteric traction syndrome (MTS) is associated with prostacyclin (PGI₂) facilitated systemic vasodilatation during surgery and is identified by facial flushing. We hypothesized that severe facial flushing would be related to the highest concentrations of plasma PGI₂ and accordingly to the highest levels of skin blood flow measured by laser speckle contrast imaging (LSCI). Patients scheduled for major upper abdominal surgery were consecutively included. Within the first hour of the procedure, facial flushing was scored according to a standardized scale, and skin blood flow (LSPU) was continuously measured on the forehead and the cheeks by LSCI. Arterial blood samples for 6-keto-PGF_1α (stable metabolite of PGI₂) and hemodynamic variables were obtained at defined time points. Overall, 66 patients were included. After 15 min of surgery, patients with severe flushing demonstrated the highest plasma 6-keto-PGF_1α concentration and the most significant decrease in systemic vascular resistance. Accordingly, the skin blood flow on the forehead (238 [201-372] to 562 LSPU [433-729]) and the cheeks (341 [239-355] to 624 LSPU [468-917]) increased and were significantly higher than for patients with moderate or no flushing (both, P = 0.04). A cut-off value for skin blood flow could be defined for both the cheeks and the forehead for patients with severe flushing vs. no flushing (425/456 LSPU, sensitivity 75/76% and specificity 80/85%). MTS is linked to an increase in facial skin blood flow during upper gastrointestinal surgery. By applying LSCI, it is possible to quantitatively register facial blood flow, and thereby provide an objective tool for intraoperative verification of MTS.

Therapeutic effects of flurbiprofen axetil on mesenteric traction syndrome: randomized clinical trial

Background

This study aimed to reveal the appropriate timing for the intravenous administration of flurbiprofen axetil for preventing mesenteric traction syndrome (MTS), caused by prostacyclin release.

Methods

In this prospective, randomized, clinical study, forty-five patients who were undergoing elective surgery for colorectal cancer via laparotomy were enrolled. Patients were randomly divided into 3 groups: a preoperative group (n = 16) receiving flurbiprofen axetil directly before surgery; a post-MTS group (n = 14) receiving following MTS onset; and a control group (n = 15) who were not administered flurbiprofen axetil. 6-keto-PGF1α, a stable metabolite of prostacyclin, levels were measured and mean blood pressures were recorded.

Results

In the preoperative group, 6-keto-PGF1α levels did not increase, blood pressure levels did not decrease, and no facial flushing was observed. In both the post-MTS and control groups, 6-keto-PGF1α levels increased markedly after mesenteric traction and blood pressure decreased significantly. The post-MTS group exhibited a faster decreasing trend in 6-keto-PGF1α levels and quick restore of the mean blood pressure, and the use of vasopressors and phenylephrine were lower than that in the control group.

Conclusions

Even therapeutic administration of flurbiprofen axetil after the onset of MTS has also effects on MTS by suppressing prostacyclin production.

Trial registration

Clinical trial number: UMIN000009111. (Registered 14 October 2012)

A reduced gastric corpus microvascular blood flow during Ivor-Lewis esophagectomy detected by laser speckle contrast imaging technique

BACKGROUND

Reduced microvascular blood flow is related to anastomotic insufficiency following esophagectomy, emphasizing a need for intraoperative monitoring of the microcirculation. This study evaluated if laser speckle contrast imaging (LSCI) was able to detect intraoperative changes in gastric microcirculation.

METHODS

Gastric microcirculation was assessed prior to and after reconstruction of gastric continuity in 25 consecutive patients operated for adenocarcinoma with open Ivor-Lewis esophagectomy while hemodynamic variables were recorded.

RESULTS

During upper laparotomy, microcirculation at the corpus decreased by 25% from baseline to mobilization of the stomach (p = .008) and decreased further (to a total decrease of 40%) following gastric pull to the thorax (p = .013). On the other hand, microcirculation at the antrum did not change significantly after gastric mobilization (p = .091). The decrease in corpus microcirculation took place unrelated to central cardiovascular variables.

CONCLUSION

Using LSCI technique, we identified a reduced microcirculation at the corpus area during open Ivor-Lewis esophagectomy. LSCI provides an option for real-time assessment of gastric microcirculation and could form basis for intraoperative stabilization of the microcirculation.

Severe Postoperative Complications may be Related to Mesenteric Traction Syndrome during Open Esophagectomy

BACKGROUND

During abdominal surgery, traction of the mesenterium provokes mesenteric traction syndrome, including hypotension, tachycardia, and flushing, along with an increase in plasma prostacyclin (PGI₂). We evaluated whether postoperative complications are related to mesenteric traction syndrome during esophagectomy.

METHODS

Flushing, hemodynamic variables, and plasma 6-keto-PGF_1α were recorded during the abdominal part of open ( n = 25) and robotically assisted ( n = 25) esophagectomy. Postoperative complications were also registered, according to the Clavien-Dindo classification.

RESULTS

Flushing appeared in 17 (open) and 5 (robotically assisted) surgical cases ( p = 0.001). Mean arterial pressure was stable during both types of surgeries, but infusion of vasopressors during the first hour of open surgery was related to development of widespread (Grade II) flushing ( p = 0.036). For patients who developed flushing, heart rate and plasma 6-keto-PGF_1α also increased ( p = 0.001 and p < 0.001, respectively). Furthermore, severe postoperative complications were related to Grade II flushing ( p = 0.037).

CONCLUSION

Mesenteric traction syndrome manifests more frequently during open than robotically assisted esophagectomy, and postoperative complications appear to be associated with severe mesenteric traction syndrome.

Severe Intraoperative Shock Related to Mesenteric Traction Syndrome

Mesenteric traction syndrome is defined as arterial hypotension, facial flushing, and tachycardia related to mesenteric traction. We describe a case of mesenteric traction syndrome refractory to catecholamine and vasopressin infusions. The patient, who had Crohn disease, developed severe distributive shock after mesenteric traction while undergoing resection of an intestinal inflammatory mass, accompanied by facial flushing and unaltered readings for pulse oximetry, capnography, and bispectral index monitoring. The absence of tachycardia in this case was attributed to long-term use of timolol. Arterial pressure returned to baseline level after approximately 30 minutes, and the postoperative period was uneventful.

Plasma pro-atrial natriuretic peptide to estimate fluid balance during open and robot-assisted esophagectomy: a prospective observational study

Background

It remains debated how much fluid should be administered during surgery. The atrial natriuretic peptide precursor proANP is released by atrial distension and deviations in plasma proANP are reported associated with perioperative fluid balance. We hypothesized that plasma proANP would decrease when the central blood volume is compromised during the abdominal part of robot-assisted hybrid (RE) esophagectomy and that a positive fluid balance would be required to maintain plasma proANP.

Methods

Patients undergoing RE (n = 25) or open (OE; n = 25) esophagectomy for gastroesophageal cancer were included consecutively in this prospective observational study. Plasma proANP was determined repetitively during esophagectomy to allow for distinction between the abdominal and thoracic part of the procedure. The RE group was 15° head up tilted during the abdominal procedure.

Results

The blood loss was 250 (150–375) (RE) and 600 ml (390–855) (OE) (p = 0.01), but the two groups of patients were provided with a similar positive fluid balance: 1705 (1390–1983) vs. 1528 ml (1316–1834) (p = 0.4). However, plasma proANP decreased by 21% (p < 0.01) during the abdominal part of RE carried out during moderate head-up tilt, but only by 11% (p = 0.01) during OE where the patients were supine. Plasma proANP and fluid balance were correlated in the RE-group (r = 0.5 (0.073–0.840), p = 0.02) and tended to correlate in the OE group (r = 0.4 (−0.045–0.833), p = 0.08).

Conclusion

The results support that plasma proANP decreases when the central blood volume is compromised and suggest that an about 2200 ml surplus administration of crystalloid is required to maintain plasma proANP during esophagectomy.

Trial registration

Clinicaltrials.gov (NCT02077673). Registered retrospectively February 12^th 2014.

Hemodynamics of mesenteric traction syndrome measured by FloTrac sensor

BACKGROUND

Mesenteric traction syndrome (MTS) develops in the early phase of laparotomy, which is triggered by pulling of the mesentery. We attempted to analyze the circulatory dynamics of MTS by using the FloTrac sensor.

METHODS

Prospective randomized control study, the MTS trial, was conducted with or without prophylactic administration of flurbiprofen axetil in order to control MTS development in 57 elective open colorectal surgeries. None of the Flurbipurofen group patients (n = 23) develop MTS and were allocated to the non-MTS group. Among the non-flurbiprofen group, 28 patients (82%) developed MTS and were categorized into the MTS group. For these patients, in addition to blood pressure, stroke volume variation (SVV) and systemic vascular resistance index (SVRI) were measured by FloTrac sensor.

RESULTS

The lowest blood pressure was noted within 30 minutes from the beginning of the intra-abdominal examination; in the non-MTS group, the mean blood pressure decreased by 16.7%, and in the MTS group, it decreased by 34.2% (P < .01). SVV of the 28 MTS patients was as follows: <9% in 10 patients (35.7%), >9% and <13% in 8 patients (28.6%), and >13% in 10 patients (35.7%). SVRI rose in the non-MTS group by 5.1%, whereas it fell in the MTS group by 15.1% (P < .01), indicating the close relationship between MTS and SVRI.

CONCLUSIONS

The SVV results indicate that fluid loading is not that optimal treatment against hypotension of MTS and that it is also important to consider the use of a vasoconstrictor. FloTrac is therefore useful for making an appropriate decision on the treatment strategy for MTS.

Intravenous flurbiprofen axetil can stabilize the hemodynamic instability due to mesenteric traction syndrome--evaluation with continuous measurement of the systemic vascular resistance index using a FloTrac® sensor

OBJECTIVE

Evaluation of the stabilizing effect of intravenous flurbiprofen axetil against hemodynamic instability due to mesenteric traction syndrome (MTS) by continuous measurement of systemic vascular resistance index (SVRI) using a FloTrac(®) sensor was evaluated.

DESIGN

Prospective randomized trial.

SETTING

A single-center study performed in an educational hospital.

PARTICIPANTS

Two prospective studies were carried out, each with 40 patients scheduled for elective open abdominal surgery.

INTERVENTION

Twenty patients received 50 mg of flurbiprofen axetil after the recognition of MTS by the anesthesiologist (group FT). The remaining patients served as controls (groups CP and CT).

MEASUREMENTS AND MAIN RESULTS

SVRI data was collected every 20 seconds for 1 hour after starting the laparotomy. The average SVRI prior to skin incision was taken as the baseline. Following 3 values were devised to evaluate MTS: the S-value (sum total of changes in SVRI from baseline), the T-value (period during which SVRI remained 20% or more below baseline), and the M-value (maximum change in SVRI from baseline). In group FP, decrease in SVRI was smaller than in group CP, and statistical differences in the 3 values were found. In group FT, SVRI recovered earlier than in group CT, and statistical differences were found in S-value and T-value. However, the M-value had no statistical differences.

CONCLUSIONS

Intravenous flurbiprofen axetil can stabilize the hemodynamic instability due to MTS.

Flurbiprofen axetil provides a prophylactic benefit against mesenteric traction syndrome associated with remifentanil infusion during laparotomy

PURPOSE

Mesenteric traction syndrome (MTS) is caused by PGI(2) release during abdominal procedures and is often observed during abdominal surgery. We have demonstrated that MTS occurs more frequently in cases using remifentanil than in those that are not. The aim of this study was to assess the prophylactic benefit of flurbiprofen axetil on MTS in patients undergoing abdominal surgery using remifentanil.

METHODS

Thirty ASA physical status I and II patients were enrolled. They were scheduled to undergo abdominal surgery under general anesthesia with remifentanil and were randomly assigned to receive flurbiprofen axetil (group F) or saline (group C) preoperatively (n = 15 each). MTS was defined according to our simplified diagnostic criteria. Arterial blood pressure and heart rate were recorded, and the plasma 6-keto-PGF(1α) (a stable metabolite of PGI(2)) concentration was measured just before skin incision and at 20 and 60 min after skin incision (T(0), T(20), T(60)) to confirm the diagnosis of MTS.

RESULTS

Twelve of 15 (80%) patients developed MTS in group C, whereas only 1 of 15 (6.7%) patients in group F developed MTS. At T(20), the group C patients showed significantly lower arterial blood pressure (P < 0.05) and a faster heart rate (P < 0.01) than those in group F. The mean plasma 6-keto-PGF(1α) concentration was significantly elevated in group C at T(20) (P < 0.01), whereas the plasma 6-keto-PGF(1α) level remained low throughout the observation period in group F.

CONCLUSIONS

We found that preoperative administration of flurbiprofen axetil reduced the incidence of MTS during abdominal surgery with remifentanil analgesia.

Is damage control orthopedics essential for the management of bilateral femoral fractures associated or complicated with shock? An animal study

BACKGROUND

The maximum score of a single anatomic system, the Injury Severity Score, may not reflect the overall damage inflicted by bilateral femoral fractures and justify the strategy of damage control orthopedics (DCO). It is necessary to investigate effects of various therapeutic procedures on such fractures with or without shock to facilitate correct decision making on DCO.

METHODS

A model of bilateral femoral fractures was made in 36 of 48 male New Zealand White rabbits. A model of bilateral femoral shaft fractures associated with shock was made. After resuscitation, a reamed intramedullary nailing fixation was performed in the first group (IM group), and an external fixation device applied in the second group (EF group), and the fractures in the third group (control group) were supported with splints only. They were divided into four groups: shock with IM nailing (shock-IM), shock with external fixation (shock-EF), shock with conservative method (shock-Cons), and intramedullary nailing without shock (nonshock-IM). Vital signs and inflammatory reactions were recorded. Thirty-six hours after the therapeutic procedures in four groups, the animals were killed for histologic evaluation.

RESULTS

The changes of vital signs were most significant in shock-IM group (p < 0.05). The exaggerated levels of interleukin-6, Interleukin-10, and tumor necrosis factor alpha concentrations demonstrated a significant difference between all the groups-shock-IM and other groups (p < 0.05). As to histologic appearances, the statistical difference varies from organ to organ. There is highly significant difference when the IM group is compared with the other two groups as far as lungs are concerned. As to the liver, there is only significant difference between the IM group and the control group. In terms of kidney and heart, there is no significant difference cross the groups. As to histologic appearances, there is highly significant difference in lungs between shock-IM group and other three groups. There is significant difference in liver between the shock-IM group and the shock-Cons group (p < 0.05). Kidneys and heart were less affected cross the groups.

CONCLUSIONS

In this study, an early reamed intramedullary nailing fixation procedure resulted in more adverse effects on system stress, inflammatory response, and multiple organs. The injuries also cause histologic damages to lungs and liver. Therefore, early reamed intramedullary nailing fixation may pose a potential risk of developing complications and adopting the DCO strategy may be more preferable. Shock and IM combined cause most severe damages, followed by IM without shock, shock plus EF, and shock plus conservative procedure in that order. If IM must be used for some reasons, it is desirable be delayed until shock has been fully controlled and vasculorespiratory stability restored.

Prostaglandin I2 release following mesenteric traction during abdominal surgery is mediated by cyclooxygenase-1

Our study aimed to determine the role of cyclooxygenase-2 in the release of prostaglandin-(PG)-I2 following mesenteric traction during abdominal surgery. In a prospective double-blind, randomized, placebo-controlled study, 40 patients electively scheduled for non-laparoscopic abdominal surgery, were pretreated with the cyclooxygenase-2 inhibitor parecoxib (n=20) or placebo (n=20). Heart rate, arterial blood pressure, oxygenation ratio and plasma concentrations of the stable PGI2-metabolite 6-keto-PGF1alpha were compared between groups before injection of parecoxib (-40 min), immediately before mesenteric traction (0 min), and 5, 10, and 30 min thereafter. In addition, plasma concentrations of valdecoxib, the active metabolite of the prodrug parecoxib, were determined. Plasma concentrations of 6-keto-PGF1alpha and heart rate increased in both groups after mesenteric traction. There were no significant differences between groups at individual times in heart rate, arterial blood pressure and plasma concentrations of 6-keto-PGF1alpha. Oxygenation ratio decreased after 10 and 30 min following mesenteric traction in the parecoxib group with a significant difference between treatment groups at 10 and 30 min. Plasma concentrations of valdecoxib revealed therapeutic values. Our data indicate that PGI2 release following mesenteric traction is mediated by cyclooxygenase-1.

Alterations in the Systemic Inflammatory Response after Early Total Care and Damage Control Procedures for Femoral Shaft Fracture in Severely Injured Patients

BACKGROUND

Recently, there has been a move away from early total care in patients with severe, multiple injuries to damage control orthopedics (DCO) in an attempt to limit the physiologic insult resulting from operative treatment after trauma. For femoral shaft fracture, this entails initial external fixation and subsequent conversion to an intramedullary nail (IMN). We sought to quantify the inflammatory response to initial surgery and conversion and link this to subsequent organ dysfunction and complications.

METHODS

Patients with femoral shaft fracture and a New Injury Severity Score of 20 or more were included. Data were retrospectively collected for 4 days at admission and at exchange procedure (external fixation to intramedullary nail), and the Systemic Inflammatory Response Syndrome (SIRS) score and the Marshall multiorgan dysfunction score were calculated.

RESULTS

One hundred seventy-four patients met the inclusion criteria. The DCO group had significantly more severe injuries (New Injury Severity Score of 25.4 vs. 36.2, p < 0.0001) and significantly more head and thoracic injuries (both p < 0.0001). The mean SIRS score was significantly higher in the IMN group, from 12 hours until 72 hours postoperatively (p < 0.05). The mean peak postoperative SIRS score was significantly higher in the IMN group than in the DCO group, at the primary procedure and at conversion, as was the time with an SIRS score greater than 1. At conversion in the DCO group, the preoperative SIRS score correlated with magnitude and duration of elevation in the SIRS and multiorgan dysfunction scores (p < 0.0001).

CONCLUSION

It would appear that despite more severe injuries in the DCO group, patients had a smaller, shorter postoperative SIRS and did not suffer significantly more pronounced organ failure than the IMN group. DCO patients undergoing conversion while their SIRS score was raised suffered the most pronounced subsequent inflammatory response and organ failure. According to these data, DCO treatment was associated with a lesser systemic inflammatory response than early total care for femur fractures. The inflammatory status of the patient may be a useful adjunct in clinical decision making regarding the timing of conversion to an intramedullary device.

The effect of general anesthesia and abdominal surgery upon plasma thromboxane B concentrations in horses

OBJECTIVE

To compare the effect of anesthesia alone with anesthesia and abdominal surgery on plasma thromboxane B(2) concentrations in horses.

STUDY DESIGN

Non-randomized experimental study.

ANIMALS

Six male mixed-bred horses (5-12 years, 350 +/- 18 kg).

METHODS

All horses were anesthetized for 2.5 hours using halothane, and a month later abdominal surgery was performed using the same anesthetic technique with a similar duration. The schedule of anesthesia included pre-medication with diazepam (0.1 mg kg(-1) IM), followed by xylazine (2.2 mg kg(-1) IV), and 10 minutes later anesthesia was induced with ketamine hydrochloride (2.2 mg kg(-1) IV). After orotracheal intubation, anesthesia was maintained with halothane. Blood samples for the determination of thromboxane B(2) (TXB(2)) were obtained before, at induction, at 60 minutes after halothane was first inspired, and at recovery from anesthesia as well as at the corresponding stages of the experimental abdominal surgery (before induction, prior to laparotomy, enterectomy, enteroanastomosis, abdominal wall closure).

RESULTS

Baseline value for the anesthesia group was 76 +/- 12 pg mL(-1) and increased (p < 0.001) after 1 hour of anesthesia to 265 +/- 40 pg mL(-1). With surgery, the corresponding value was 285 +/- 21 pg mL(-1) (hour 1, p < 0.001) and 210 +/- 28 pg mL(-1) (hour 2, p < 0.001), respectively. These were not different from anesthesia alone.

CONCLUSION

The increased concentrations of thromboxane B(2) between 1 and 2.5 hours of halothane anesthesia and during the corresponding stages of the surgical intervention suggested that the anesthetic technique caused a significant increase in thromboxane B(2) and that surgery did not appear to contribute to this response.

The effects of different weaning modes on the endocrine stress response

Introduction

The aim of the present study was to investigate the effects of the stress response on plasma insulin, cortisol, glucose, and urinary vanilmandelic acid during weaning and after extubation, using pressure support (PS), continuous positive airway pressure (CPAP) and T-piece modes.

Methods

Sixty patients were randomly divided into three groups (n = 20). The PS group received FiO₂ ≤ 0.4, PS ≤ 10 cmH₂O, and positive end expiratory pressure ≤ 5 cmH₂O for 2 hours. The CPAP group was given FiO₂ ≤ 0.4 and CPAP 5 ≤ cmH₂O for 2 hours. The T-piece group (group T) received 4 l/min oxygen via a T-piece for 2 hours. After 1 hour and 2 hours in their respective weaning modes, blood and urine samples were taken for insulin, cortisol, glucose and vanilmandelic acid measurements. Forty-eight hours after extubation, blood and urine samples were again taken.

Results

Plasma insulin was greater in group T than in the PS and CPAP groups (P < 0.01 and P < 0.01). The plasma cortisol concentration was greater in group T than in group PS during weaning (P < 0.05) and after extubation (P < 0.05). Blood glucose concentrations were greater in group T than in the other groups (both P < 0.01) both during weaning and post extubation. Urine vanilmandelic acid was greater in group T than in the other groups during weaning and after extubation (both P < 0.001).

Conclusion

Weaning via the T-piece caused a greater stress response than the PS and CPAP modes.

A case of electrical storm in a liver transplant patient

Electrical storm has not been well described in liver transplant patients. We present a case of sympathetically mediated recurrent ventricular fibrillation in a young patient transplanted for acute Wilson's disease. This case highlights the role of the sympathetic nervous system in causing electrical storm and it demonstrates the ability of beta-blocking agents to terminate the event. In young liver transplant patients, beta-blocking agents should be considered for therapy of perioperative electrical storm if there is no known structural or coronary heart disease and when there are no risk factors for, or evidences of, torsades de pointes.

Stress response during weaning after cardiac surgery

We compared the effects of weaning using synchronized intermittent mandatory ventilation (SIMV) with the use of biphasic positive airway pressure (BIPAP) on the stress response, oxygen uptake (VO2) and work of breathing (WOB) in 10 patients after aortocoronary bypass surgery. All three ventilatory settings were investigated in each patient, for example, volume-controlled mechanical ventilation immediately before weaning was followed, in randomized order, by both SIMV and BIPAP. In addition to routine monitoring of continuous and respiratory state, we measured VO2, WOB, and pressure-time product (PTP) as well as the plasma concentrations of epinephrine, norepinephrine, ACTH, cortisol, vasopressin, and prolactin. Although respiratory rate (f), WOB and PTP were greater with both SIMV and BIPAP when compared with control, other variables did not change with the ventilatory mode. In conclusion, weaning from mechanical ventilation using partial support modes does not affect the postoperative stress response in patients who have had uncomplicated cardiac surgery.