Effect of adrenergic stimulation on cutaneous microcirculation immediately after surgical adventitiectomy in a rat skin flap model

Anaesthesia for reconstructive free flap surgery for head and neck cancer

Head and neck cancer surgery presents significant challenges for the anaesthetist. A thorough multidisciplinary preoperative assessment and optimisation of the patient is essential, including nutritional and psychological evaluation. The incidence of a difficult airway is high, and the anaesthetist must be skilled in advanced airway techniques. Surgery is extensive, often requiring reconstructive surgery with either a pedicled or free flap. Detailed knowledge of flap physiology and anatomy is needed, and anaesthesia comprises careful management of mean arterial pressure, fluid administration, temperature control and oxygenation. The Enhanced Recovery after Surgery Society and the Society for Head and Neck Anaesthesia consensus recommendations provide guidance on current best practice. Despite continued debate, it now appears that this constitutes goal-directed fluid therapy, coupled with judicious vasopressor therapy sufficient to achieve an adequate mean arterial pressure. Emerging techniques such as prehabilitation and postoperative near-infrared spectroscopy flap monitoring provide hope of improved outcomes going forward.

The Efficacy of Hydrodilatation for the Prevention of Vasospasm following Microsurgical Anastomosis

INTRODUCTION

 Vasospasm is a major problem following microsurgical reconstruction which can result in the partial or complete loss of the flap tissue. The aim of this study was to investigate the efficiency of hydrodilatation for the prevention of vasospasm.

MATERIAL AND METHODS

 Thirty male Wistar rats were used for this experimental study. Femoral arteries of were exposed, photographed, and transected. In group 1, group 2, and group 3 papaverine solution, hydrodilatation, and minimal mechanical dilatation (control group) was performed, respectively. The anastomosis was completed and the arteries were photographed again 10 minutes after completion of the anastomosis. Following 7-day period samples for transmission electron microscopy (TEM) and light microscopy were obtained.

RESULTS

 The mean vessel diameters prior to transection were 0.43, 0.45, and 0.52 mm in the papaverine, hydrodilatation, and control groups, respectively. The mean vessel diameter 10 minutes following the completion of anastomosis was 0.76, 0.75, and 0.51 mm in the papaverine, hydrodilatation, and control groups, respectively. Median score for papaverine group regarding histological parameters of regular endothelial lining and lumen, neutrophil infiltration, vascular congestion, and edema in tunica adventitia was 2, 3, 2, and 3 positive, respectively. Median score for the papaverine group regarding histological parameters of regular endothelial lining and lumen, neutrophil infiltration, vascular congestion, and edema in tunica adventitia was 3, 3, 3, and 3 positive, respectively. All the histological scores were negative in the control group. The difference between the control group and the experiment groups 1 and 2 was significant regarding all four histological parameters (p < 0.05).

CONCLUSION

 Hydrodilatation and papaverine application were both effective in preventing vasospasm following microsurgical intervention but papaverine caused slightly less damage to the endothelial lining and less edema in the tunica adventitia when compared with the hydrodilatation. Hydrodilatation group showed a vasodilatory effect that was statistically similar to that of papaverine, which has a proven efficacy.

The Effect of Very Low Concentrations of Ethanol on Microvascular Artery and Vein Anastomosis: An Experimental Study

OBJECTIVES

This study investigated the effect of very low concentrations of ethanol on artery and vein anastomosis. Also, it was aimed to determine the appropriate ethanol concentration to be used in vasospasm.

METHODS

Rats were divided into five groups of eight rats, each group, as follows: Group i: saline; Group ii: 2.5% ethanol; Group iii: 5% ethanol; Group IV: 7.5% ethanol; and Group V: 10% ethanol. During the femoral artery and vein anastomosis, 1ml of the agent was used for irrigation in each group. Vessel diameters were measured before the anastomosis, at the fifth and 15th minutes, and the third week after the anastomosis. Histopathological samples were taken in the third week.

RESULTS

In Groups ii and iii, the mean vessel diameters were found to increase 15th minute. Also observed was an increase in mean vessel diameter that continued in the third week. Although acute vasodilation was detected in Groups IV and V, arterial and venous thrombosis was observed in the third week. Intima and media thickness decreased in Group ii, while it increased in Group iii. Perivascular inflammation and fibrosis increased as the ethanol concentration increased.

CONCLUSION

2.5% ethanol causes acute and prolonged vasodilation and does not cause endothelial cell damage, perivascular inflammation, and fibrosis. 2.5% ethanol will be a powerful alternative use in many situations that occur with vasospasm.

Perioperative predictors of early surgical revision and flap-related complications after microvascular free tissue transfer in head and neck reconstructions: a retrospective observational series

Objectives

The aim of this study was to determine the influence of perioperative fluid management and administration of vasopressors on early surgical revision and flap-related complications in free tissue transfer.

Materials and methods

Intraoperative amount of fluid and of vasopressors, relevant perioperative parameters, and comorbidities were recorded in 131 patients undergoing head and neck microvascular reconstruction and compared with early surgical complications, defined as interventions requiring surgery after a flap-related complication, and/or other surgical problems in the operating room within 30 days after initial surgery. The relationship between perioperative variables for each revision category was determined using an optimized multiple logistic regression.

Results

The administration of diuretics (p=0.001) as a treatment for perioperative fluid overload and the type of flap (p=0.019) was associated with a higher risk of early surgical revisions. Perioperative fluid overload (p=0.039) is significantly related to flap-related complications. We found no effect of intraoperative administration of vasopressors on early surgical revisions (p=0.8) or on flap-related complications (norepinephrine p=0.6, dobutamine p=0.5).

Conclusion

Perioperative fluid overload is associated with higher risks of early surgical revision and flap-related complications. In contrast, the administration of vasopressors seemed to have no effect on either surgical revision rate or flap-related complications.

Clinical relevance

In patients receiving microvascular reconstructions, a balanced fluid administration perioperatively and a targeted use of vasopressors should be the necessary strategy to reduce the complication rates in head and neck surgery.

The Use of Vasopressor Agents in Free Tissue Transfer for Head and Neck Reconstruction: Current Trends and Review of the Literature

Background/Objectives

Microvascular free tissue transfer has become essential to head and neck reconstruction and recent advancements in microvascular surgery have led to excellent surgical outcomes. However, there continues to be controversy and a stigma associated with the use of perioperative intravenous vasopressor agents among both surgeons and anesthesiologists. Due to concern for vasoconstriction of peripheral vasculature flowing to the denervated tissue flap, there remains concerns about potential thrombosis, decreased tissue perfusion and ultimately flap failure. This topic becomes even more important as vasopressors play an essential role in new Extended Recovery After Surgery (ERAS) protocols being put in place to optimize postoperative recovery for patients. The purpose of this study was to comprehensively review the role and safety as well as discuss current trends with intraoperative vasopressor agents in free tissue transfer for head and neck reconstruction.

Methods

A scoping literature review was conducted of all studies that examined the use of vasopressor agents during head and neck free flap tissue transfer. Primary and secondary outcomes included free flap survival, arterial thrombosis, venous congestion, need for revision surgery, and other postoperative complications.

Results

One prospective and nine retrospective studies were identified. Phenylephrine and ephedrine were the most common vasopressors reported; the rate of vasopressor use ranged from 53% to 85% and administration methods included both bolus and infusion. The included studies did not show any significant association between the use of vasopressors and free flap failure, pedicle thrombosis, or other flap complications.

Conclusion

The administration of vasopressors during microvascular free tissue transfer for head and neck reconstruction does not seem to be associated with increased flap failure rates or other postoperative morbidities. Moreover, vasopressors may provide overall improved hemodynamic stability and help to limit overall fluid administration and subsequent postoperative complications. Additional prospective investigation is warranted to further elucidate and establish evidence-based recommendations regarding the type, timing, and dose of vasopressors to further enhance free flap survival and patient outcomes.

Perioperative considerations in free flap surgery: A review of pressors and anticoagulation

Given the high stakes for microvascular reconstruction, the majority of reconstructive surgeons have developed paradigms for pre, intra, and postoperative management that have proven to result in individual high success rates. Much has been done to identify and avoid perioperative factors that could potentially increase flap failure rates. Two example of this practice has been the generalized use of anticoagulation in free tissue transfer and the prohibition against vasopressor use in patients that are undergoing free tissue transfer. This manuscript will discuss these issues.

Phenylephrine infusion impact on surgical site infections after lower extremity bypass surgery

OBJECTIVE

Lower extremity bypass (LEB) operations have high rates of surgical site infections (SSI). Phenylephrine is a commonly used vasoconstrictor which may reduce skin blood flow and increase the likelihood of SSI in these patients. We studied the potential effect of phenylephrine infusion during LEB surgery on SSI.

METHODS

LEB cases and their demographic data were identified through the Vascular Quality Initiative registry. SSI in this population was identified using the hospital epidemiology surveillance database. Phenylephrine use in this population was identified through chart review.

RESULTS

We identified 699 patients who underwent LEB; 82 (11.7%) developed an SSI, and 244 of 698 (35.0%) were treated with phenylephrine infusion. In bivariate analysis, higher body mass index (28.8 kg/m² vs 27.3 kg/m²; P = .034), diabetes (14.6% vs 9.4%; P = .035), hypertension (12.6% vs 4.7%; P = .038), groin incision (13.2 vs 5.4%; P = .013) and longer procedure times (17.1% for >220 minutes and 8.9% for ≤220 minutes; P = .003) were associated with higher rates of SSI. Whereas phenylephrine infusion exhibited a trend toward a higher rate (14.8% vs 9.9%; P = .057). In the logistic regression model, diabetes (odds ratio [OR], 1.8; 95% confidence interval [CI], 1.0-3.2; P = .032), total procedure time (OR, 1.85; 95% CI, 1.1-3.1; P = .026) and vertical groin incision (OR, 2.6; 95% CI, 1.1-6.5; P = .035) were independent predictors of increased SSI rates, whereas body mass index (OR, 1.04; 95% CI, 0.99-1.08; P = .09), hypertension (OR, 2.5; 95% CI, 0.6-10.9; P = .22), and phenylephrine infusion (OR, 1.08; 95% CI, 0.63-1.85; P = .78) were not independent predictors of increased SSI rates.

CONCLUSIONS

Phenylephrine infusion did not increase the risk of SSI in patients who underwent LEB.

The Effect of Norepinephrine and Dopamine on Radial Forearm Flap Partial Tissue Oxygen Pressure and Microdialysate Metabolite Measurements: A Randomized Controlled Trial

BACKGROUND

Patients undergoing ablative and reconstructive head and neck surgery with a microvascular flap have multiple factors that potentially decrease postoperative mean arterial pressure, which may endanger flap survival. The safety of vasopressor use has long been a topic of discussion. The authors analyzed the effect of vasopressors on microvascular flap perfusion after head and neck cancer reconstruction.

METHODS

A total of 27 patients were enrolled in a randomized, controlled, clinical trial. A microvascular radial forearm flap was used for reconstruction. Patients were allocated into one of three groups: dopamine, norepinephrine, and control. The intervention groups received the vasoactive drug, aiming to maintain the mean arterial pressure between 80 and 90 mmHg. Normovolemia was maintained according to central venous pressure. Flap perfusion was monitored with continuous tissue partial pressure of oxygen and microdialysate metabolite (lactate-to-pyruvate ratio) measurements.

RESULTS

No adverse effects were observed, and postoperative recovery was free of complications in all groups. Neither the lactate-to-pyruvate ratio nor continuous tissue partial pressure of oxygen values differed significantly between groups during the first 24 hours of the vasoactive drug infusion period or during the 72-hour follow-up.

CONCLUSIONS

Norepinephrine and dopamine are safe and effective vasopressors for use during the postoperative period following head and neck cancer surgery with microvascular reconstruction. Dopamine should be used with caution, however, because of the risk of side effects.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, II.

The effects of limited adventitiectomy on vascular anastomosis: An experimental study in rats

OBJECTIVE

Blockages in anastomotic vessels cause complete loss of free tissue transfer and replanted limb. Many studies have been conducted in the last 30 years to solve this problem. There are insufficient studies dealing with the effects of the limited adventitiectomy done before surgery for sympathetic overactivity leading situations. The aim of this experimental study is to reveal the effects of limited adventitiectomy.

METHODS

In this study, limited adventitiectomy was performed in a wide area before surgery, and the effect of this practice on the vessel diameter and anastomosis was investigated.

RESULTS

Rapidly growing dilatation and increase in vessel diameter was observed, and dilatation continued in the limited adventitiectomy group.

CONCLUSIONS

The preoperative performed limited adventitiectomy is a useful preparation for super microsurgery. Especially in clinical practice before the free flap surgery, limited adventitiectomy can be applied if the recipient site is expected to have vascular problems.

Metamizole: an effective solution for vasospasm

OBJECTIVE

Vasospasm is a major problem during microsurgery, and a variety of pharmacological agents are used to alleviate vasospasm. This study aimed to demonstrate the effect of metamizole on vasospasm and to compare it with lidocaine and papaverine, both of which are commonly used to correct vasospasm.

METHODS

Thirty-five female rats were randomly divided into four groups: Group 1, 2, 3, and 4, which were the control (n = 8), metamizole (n = 9), papaverine (n = 9), and lidocaine (n = 9) treatment groups, respectively. Both femoral arteries of all of the rats were dissected, and they were immediately photographed. The pharmacological agents or saline in the control group were topically applied to the arteries, accordingly. The arteries were photographed again at time points 5, 10, 20 and 30 minutes after application of the agents. The images were transferred to a computer and the arteries' diameters were measured in mm.

RESULTS

All of the pharmacological treatments increased the diameter of the arteries significantly during the observation period. However, comparison between the groups indicated that metamizole and papaverine produced significantly more vasodilation than the lidocaine group, for all time points measured after application.

CONCLUSION

These findings show that topically applied metamizole is as effective as papaverine at alleviating vasospasm during the 30 minutes time interval. This administration may be considered as a good alternative to correct vasospasm during microsurgery.

Vasopressors and reconstructive flap perfusion: a review of the literature comparing the effects of various pharmacologic agents

INTRODUCTION

Use of intraoperative vasopressors is of debate in microvascular surgery. Anesthesia is an important factor in maintaining the rate of success of flap transfer by affecting regional blood flow and global hemodynamics. We conducted a review of the literature comparing the use of different vasoactive agents on different flaps in various human and animal models.

METHODS

A systematic review of the literature was performed. Bibliographies of key articles were also reviewed for additional resources. Analysis was done to determine the overall trend of how flap perfusion is affected by the use of intraoperative vasoactive medication.

RESULTS

The literature search identified 16 relevant articles. Flaps were studied in pigs in 7 studies, rats in 5, and humans in 4. The most common flap was the rectus abdominis musculocutaneous flap. Phenylephrine and norepinephrine were the most common pressor agents used. No significant statistical changes were noted in 8 of the 16 studies; initial ischemia followed by delayed improved perfusion was observed in 4 studies, "true ischemia" and hypoperfusion of the skin flaps was noted in 3. There was no consistency in their effect on flap perfusion: initial ischemia followed by delayed improved perfusion was observed in 4 studies, whereas true ischemia and hypoperfusion of the skin flaps was noted in 3.

CONCLUSIONS

To date, there is no reliable prospective clinical evidence that supports the absolute contraindication of pressor agents during free flap surgery. This topic will continue to be a matter for debate until more definitive data can be obtained.

Emerging paradigms in perioperative management for microsurgical free tissue transfer: review of the literature and evidence-based guidelines

BACKGROUND

Microsurgical free tissue transfer has become an increasingly valuable technique in reconstructive surgery. However, there is a paucity of evidence-based guidelines to direct management. A systematic review was performed to define strategies to optimize perioperative management.

METHODS

A systematic review of the literature was performed using key search terms. Strategies to guide patient management were identified, classified according to level of evidence, and used to devise recommendations in seven categories: patient temperature, anesthesia, fluid administration/blood transfusion, vasodilators, vasopressors, and anticoagulation.

RESULTS

A total of 106 articles were selected and reviewed. High-level evidence was identified to guide practices in several key areas, including patient temperature, fluid management, vasopressor use, anticoagulation, and analgesic use.

CONCLUSIONS

Current practices remain exceedingly diverse. Key strategies to improve patient outcomes can be defined from the available literature. Key evidence-based guidelines included that normothermia should be maintained perioperatively to improve outcomes (level of evidence 2b), and volume replacement should be maintained between 3.5 and 6.0 ml/kg per hour (level of evidence 2b). Vasopressors do not harm outcomes and may improve flap flow (level of evidence 1b), with most evidence supporting the use of norepinephrine over other vasopressors (level of evidence 1b). Dextran should be avoided (level of evidence 1b), and pump systems for local anesthetic infusion are beneficial following free flap breast reconstruction (level of evidence 1b). Further prospective studies will improve the quality of available evidence.

Impact of intraoperative vasopressor use in free tissue transfer for head, neck, and extremity reconstruction

General anesthesia induces hypotension and this is commonly treated intraoperatively with administering vasopressors. Microsurgeons are hesitant to use vasopressors due to the potential risk of inducing vasoconstriction and flap necrosis. The aim of this study was to determine the frequency of intraoperative vasopressor utilization in patients undergoing free tissue transfer reconstruction and to determine its impact on patient outcomes. An IRB-approved retrospective review was performed for 47 consecutive patients undergoing free tissue transfer for head, neck, and extremity reconstruction at Wake Forest Baptist Health over a 3-year period. Free flap survival was 97%, with 3% of patients having total flap necrosis and 17% with partial flap necrosis. The frequency of intraoperative vasopressor use was 53.2%. There was no significant difference in the frequency of total or partial flap necrosis between patients who received intraoperative vasopressors and those who did not. Similarly, there was no statistical significance in the rate of arterial or venous thrombosis between the 2 groups (P = 0.095 and P = 0.095, respectively). The use of vasopressors did not significantly increase postoperative complications. The timing of vasopressor administration did not affect outcomes. Intraoperative vasopressors are used more frequently than previously realized during free tissue transfer for reconstructive surgery. The use of intraoperative vasopressors does not appear to adversely affect outcomes of free tissue transfer. Further investigation and larger study size are needed to analyze the timing of drug administration, dose, and type of vasopressor to better understand the impact of intraoperative vasopressor use in free tissue transfer outcomes.

Anaesthesia and intensive care management of face transplantation

The face-grafting techniques are innovative and highly complex, requiring well-defined organization of all the teams involved. Subsequent to the first report in France in 2005, there have been 17 facial allograft transplantations performed worldwide. We describe anaesthesia and postoperative management, and the problems encountered, during the course of seven facial composite tissue grafts performed between 2007 and 2011 in our hospital. The reasons for transplantation were ballistic trauma in four patients, extensive neurofibromatosis in two patients, and severe burns in one patient. Anaesthesia for this long procedure involves advanced planning for airway management, vascular access, technique of anaesthesia, and fluid management. Preparation and grafting phases were highly haemorrhagic (>one blood volume), requiring massive transfusion. Median (range) volumes given for packed red cell (PRC) and fresh-frozen plasma (FFP) were 64.2 ml kg(-1) (35.5-227.5) and 46.2 ml kg(-1) (6.3-173.7), respectively. Blood loss quantification was difficult because of diffuse bleeding to the drapes. The management of patients with neurofibromatosis or burns involving the whole face was more difficult and haemorrhagic than the patients with lower face transplantation. Average surgical duration was 19.1 h (15-28 h). Postoperative severe graft oedema was present in most patients. Most patients encountered complications in ICU, such as renal insufficiency, acute respiratory distress syndrome, and jugular thrombosis. Opportunistic bacterial infections were a feature during the postoperative period in these highly immunosuppressed patients.

Preoperative anemia predicts thrombosis and free flap failure in microvascular reconstruction

Patients undergoing microvascular reconstruction are often anemic from a combination of iatrogenic hemodilution and acute blood losses. No major clinical study describes the impact of preoperative anemia on free flap morbidity. The plastic surgery service at a high-volume academic center performed 156 free flaps among 147 patients from December 2005 to December 2010. One hundred thirty-two had a preoperative hemoglobin (Hb) or hematocrit (Hct), with mean values of 11.8±2.4 g/dL and 35.2%±7.0%, respectively. The overall failure rate was 9% (12/132), primarily from vascular thrombosis (6/12). Through logistic regression analysis, Hb and Hct were significant predictors of flap failure (P<0.005) and vascular thrombosis (P<0.05). Fisher exact test revealed a significant increase in failure risk at Hct level less than 30% (Hb<10 g/dL) (relative risk, 4.76, P=0.006), and probit analysis demonstrated an exposure-response relationship to decreased Hct level (P<0.005). These findings support that preoperative anemia could significantly impact free flap morbidity.

Impact of vasopressors on outcomes in head and neck free tissue transfer

OBJECTIVES/HYPOTHESIS

The primary objective of the study was to determine the frequency of intraoperative vasopressor administration among patients undergoing free tissue transfer for head and neck reconstruction, and the secondary objective was to determine the impact of intraoperative vasopressor on free tissue transfer outcomes, including the impact of cumulative vasopressor dose and timing of intraoperative vasopressor administration.

STUDY DESIGN/METHODS

A retrospective review was performed of all patients undergoing free tissue transfer for head and neck reconstruction at the University Health Network between 2004 to 2008.

RESULTS

From 2004 to 2008 inclusive, 485 patients underwent 496 free tissue transfers for head and neck reconstruction. The complete failure rate was 2.2% (11 of 485 patients). The partial failure rate was 1.4%, and the operative take-back rate for venous congestion or arterial thrombosis was 1.6%. This gave a total major flap complication rate of 5.2%, which was used as the primary free tissue transfer outcome measure. Of the 485 patients who underwent free tissue transfer, 320 (66.0%) received intraoperative vasopressor. Of these patients, the majority (97.5%) received phenylephrine and/or ephedrine. There was no significant relationship between receiving intraoperative vasopressor and major free flap complications, which were defined as complete failure, partial failure, or operative take-back for venous congestion or arterial thrombosis.

CONCLUSION

Intraoperative vasopressors are used routinely in free tissue transfer for the reconstruction of head and neck defects. The use of intraoperative vasopressors does not appear to adversely affect free tissue transfer outcomes.

Effects of buflomedil and pentoxifylline on hamster skin-flap microcirculation: prediction of flap viability using orthogonal polarization spectral imaging

OBJECTIVE

This study investigated the effects of buflomedil and pentoxifylline, both of which are used in reconstructive surgery of hamster skin flap microcirculation, and evaluated the skin flap survival rate by orthogonal polarization spectral imaging.

METHOD

Twenty-four adult male Syrian golden hamsters were divided into three groups: a control (C, 0.1 ml 0.9% saline), buflomedil (B, 3 mg/kg/day), and pentoxifylline group (P, 14.5 mg/kg/day). Treatments administered intraperitoneally were initiated 1 hour before skin flap preparation and continued for 7 days post-operatively at 12-hour intervals. Preparations (skin flaps) were divided into 12 fields, which were organized into six bands. Functional capillary density (FCD, in mm/mm(2)), distance from the skin flap base to blood flow cessation (Dist(with flow), in cm), percentage of viable skin (VA, in%), and qualitative analysis of blood flow by orthogonal polarization spectral imaging were performed at 1 and 24 hours and on the seventh post-operative day.

RESULT

Bands IV, V, and VI presented no flow independent of time. The functional capillary density group B was higher than that of groups C and P, primarily after 24 hours. All groups showed an increase in D with time but reached similar final distances (C = 2.73, B = 2.78 and P = 2.70 cm). Moreover, the percentage of viable areas remained at approximately 50%. The orthogonal polarization spectral imaging was useful to assess viability by counting fields with and without blood flow.

CONCLUSIONS

Functional capillary density values were higher in the buflomedil group compared to the control and pentoxifylline groups in this model. Functional capillary density did not influence D or the percentage of VA, and the technique showed favorable potential to assess/predict the viability of skin flaps within 1 h after surgery.