Establishment of a clinical nurse specialist-led, virtual aneurysm surveillance clinic

BACKGROUND

The COVID-19 pandemic has necessitated significant changes to the manner in which healthcare is delivered. Chief among these has been the need to rapidly adopt virtual, or telephone clinics as a means of reducing unnecessary patient exposure to hospitals and clinical care settings. We were greatly aided in our adoption of virtual clinics by our experience in the establishment and maintenance of a Clinical Nurse Specialist-led, virtual clinic for both abdominal aortic (AAA) and extra-aortic aneurysm (EAA) surveillance within our department since 2016. Patients undergoing surveillance for abdominal aortic aneurysm (AAA) require frequent and lifelong clinical review. Previous studies have shown that post-operative surveillance in particular is critical in prolonging survival in AAA patients and in the early detection of late complications particularly following endovascular repair (EVAR). Poor compliance with EVAR surveillance has been shown to result in worse outcomes.

AIM

The aim of this study was to evaluate the success of a nurse-led virtual clinic programme in terms of the safe management of patients undergoing AAA surveillance in a nurse-led virtual clinic.

RESULTS

Over the course of the 4-year period from 2016 to 2019, 1352 patients were enrolled in the virtual aneurysm surveillance clinic. The majority of patients each year were male, ranging from 78.2% in 2016 to 85.2% in 2017. The majority of patients encountered the service owing to pre-operative surveillance of an AAA, with this group comprising at least 65% of the total cohort of patients each year.Over the course of the 4-year period of the virtual clinic there were 1466 patient encounters. Each ambulatory day care centre (ADCC) attendance normally costs the hospital €149. Therefore, a total saving of €218,434 resulted from this initiative alone. No patient presented as an emergency with a ruptured aneurysm during the time period studied.

CONCLUSION

Patients with AAA can be safely kept under surveillance in a nurse-led virtual clinic. Our experience with this model of care proved to be particularly advantageous during the period of the early COVID-19 pandemic.

The impact of the establishment of a surgical high dependency unit on management of Abdominal Aortic Aneurysm

BACKGROUND

Our ability to maintain satisfactory levels of outcome after elective abdominal aortic aneurysm (AAA) surgery is increasingly strained by rising levels of co-morbidity in the presenting population. In this study we present a comparative outcome analysis of patients undergoing elective AAA surgery 18 months before and after the establishment of a surgical high dependency unit (HDU).

METHODS

The preoperative status (ASA and POSSUM scores), operative factors and postoperative outcomes as well as duration of stay were calculated for 104 patients undergoing elective AAA repair (57 prior to the HDU opening and 47 patients afterwards).

RESULTS

Patients undergoing surgery in the latter period had significantly higher ASA (2.5 +/- 0.06 versus 2.7 +/- 0.7; p = 0.007), overall POSSUM (33.2 +/- 0.5 versus 35.5 +/- 0.8; p = 0.02) and physiological POSSUM (16.3 +/- 0.3 versus 15.5 +/- 0.2; p = 0.048) scores than those operated on prior to establishment of the HDU (data are mean +/- SEM; 2-tailed p-score). The two groups had similar total lengths of hospital stay (518 versus 534 days). However, following establishment of the HDU patients occupied fewer ICU bed days (110 versus 181). This resulted in a saving of Euro 50,750.

CONCLUSION

The efficiency and quality of care following elective AAA surgery can be improved by provision of HDU step-down facilities without significantly increased expenditure.

The Effect of Perioperative β-blockade on the Pulmonary Function of Patients Undergoing Major Arterial Surgery

INTRODUCTION

Concern about the potential detrimental side-effects of beta-blockade on pulmonary function often dissuades against their perioperative use in patients undergoing major arterial surgery (especially in those with chronic obstructive pulmonary disease (COPD)). In this study we aimed to establish prospectively the clinical relevance of these concerns.

METHODS

After ethics committee approval and individual informed consent, the pulmonary function of twenty patients (mean age 68.7 years (range 43-82), 11 males) scheduled to undergo non-emergency major vascular surgery was studied by recording symptoms and spirometry before and after institution of effective beta-blockade. Fifteen patients (75%) had significant smoking histories (mean pack years/patient=50), while 12 (60%) had COPD.

RESULTS

All patients tolerated effective beta-blockade satisfactorily without developing either subjective deterioration in symptoms or significant change on spirometry. The mean change in FEV1 following adequate beta-blockade was 0.05+/-0.24 liters (95% CI -0.06 to +1.61), p=0.35, giving a mean percentage change of 3.18%+/-11.66 (95% CI -2.26 to 8.62).

CONCLUSIONS

Previously held concerns about worsening pulmonary function through the short-term use of beta-blockers should not dissuade their perioperative usage in patients with peripheral vascular disease. Furthermore, the accuracy of pulmonary function tests in preoperative assessment and risk stratification also appears unaffected by this therapy.

Prospective evaluation of the efficacy of dermal botulinium toxin for primary axillary hyperhidrosis

BACKGROUND

Primary axillary hyperhidrosis (PAH) is an embarassing, socially disabling condition, most commonly seen in young people. Previous treatments for this condition have included sympathectomy or axillary skin excision. Recently botulinum toxin has been used to provide effective, non-invasive treatment for this condition.

AIMS

To investigate the effect of botulinum toxin injection in patients with PAH on sweat production and psychological wellbeing.

METHODS

Ten patients were assessed before treatment with botulinum toxin injection using gravimetric analysis and a psychometric questionnaire. Patients were reassessed at intervals of one, four and twelve weeks following treatment.

RESULTS

Injection with botulinum toxin resulted in significant improvement in patients physical symptoms and psychological wellbeing. However, improvement was short-lived with recurrence of symptoms at three months.

CONCLUSION

Botulinum toxin injection provides very effective short-term relief of PAH. While its limitations should be recognised and explained when consenting patients for treatment, this does not necessarily diminish its value in the treatment of PAH.

Aorto-enteric fistula: changing management strategies

BACKGROUND

Traditionally treatment of aorto-enteric fistulae involved placement of an extra-anatomic bypass and graft excision. This is associated with limb loss (10-40%) and high mortality (10-70%). More recently in situ revascularisation has been advocated.

AIMS

To examine our experience with the changing management of aorto-enteric fistulae over a 22-year period.

METHODS

Demographic, clinical, operative and pathological data were recorded retrospectively.

RESULTS

Twenty-one patients were included. Seven had primary fistulae. Six died prior to intervention. Five had an extra-anatomical bypass (60% mortality, 40% limb loss), four had in-situ revascularisation (25% mortality), four had a primary repair (25% mortality) and two had insertion of a tube graft (primary fistulae). The overall survival rate was 38%. The postoperative survival rate was 6o%.

CONCLUSION

Techniques for operative management continue to evolve. The current trend is towards a local surgical approach with prolonged and intensive postoperative antimicrobial therapy. In our experience this approach has yielded acceptable outcomes.

Management of patients undergoing splenectomy in an Irish teaching hospital: impact of guidelines

INTRODUCTION

Overwhelming post-splenectomy infection (OPSI) has a 50-70% mortality rate and carries a lifetime risk for the asplenic patient. Specific British guidelines have been developed to reduce its incidence.

AIMS

To determine whether British guidelines were being followed in our own institution and what impact they had on overwhelming post-splenectomy infection.

METHODS

Retrospective chart review of 100 splenectomies performed by Department of Surgery, Beaumont Hospital from January 1990 to January 2000.

RESULTS

Twenty per cent of patients were discharged without any recommended vaccinations. Prophylactic antibiotics were not prescribed in 53% of patients. Just 12% of charts document a verbal explanation of the complications and management of asplenia to the patient. Overall septic mortality was 12%, of whom 8% died in hospital and 4% after discharge.

CONCLUSION

Management of the asplenic patient has improved but is far from complete. A central register of asplenic patients and national asplenic guidelines should be established in Ireland to ensure optimum patient care.

Traumatic pseudoaneurysm of the internal carotid artery presenting with oculosympathetic palsy

BACKGROUND

Blunt internal carotid artery (ICA) injury is rare but undiagnosed can have disastrous clinical consequences.

AIM

To report a late presentation of blunt ICA injury in a young male following a road traffic accident.

RESULT

A 16-year-old male presented 11 days following a head injury with a unilateral Horner's syndrome. Imaging confirmed a pseudoaneurysm of the ICA. The patient was treated with anticoagulant therapy.

CONCLUSION

Diagnosis of ICA injury requires a high index of suspicion and presentation with unusual neurological signs following blunt trauma to the head and neck requires prompt investigation.

Current Diagnosis and Management of Blunt Internal Carotid Artery Injury

BACKGROUND

Blunt carotid artery injury (BCI) is a rare but potentially devastating injury. When undiagnosed it can result in severe disability or death.

METHODS

A Medline-based literature search was performed using key words 'blunt carotid injury' and cross-referenced with further original papers obtained from the references from this search.

RESULTS AND CONCLUSIONS

The incidence of BCI is very low. However, given the serious consequences of a missed injury, recent efforts have focussed on targeted screening for this injury in trauma patients. Conventional angiography remains the investigation of choice but may be superceded in the future by non-invasive methods such as magnetic resonance angiography or CT angiography. Operative intervention is rarely required and anti-coagulation remains the treatment of choice where dissection or pseudoaneurysm is diagnosed. The role of anti-platelet therapy is currently being investigated. Endovascular management using stents has been described but medium to long term results are not yet available.

Radiation-induced femoral arteritis

Radiation arteritis is currently an uncommon sequalae of external beam radiation, however because of the increasing use of radiotherapy in the management of neoplastic conditions its recognition is increasingly important. We present two cases of debilitating femoral occlusive disease, secondary to radiation exposure, at a long period post irradiation and review the pathophysiolgy and management options for this condition.

Endoluminal graft stenting of peripheral aneurysms: questionable results compared with conventional surgery

Popliteal and femoral aneurysms can be treated by endoluminal graft stenting, instead of conventional surgery. Results in four cases suggest, however, that long-term results do not justify an endovascular approach.

Bilateral subclavian steal syndrome

BACKGROUND

Bilateral atherosclerotic subclavian artery occlusion is rare.

AIM

To describe the surgical treatment of a patient with symptomatic bilateral subclavian artery occlusion.

METHODS

A midline sternotomy and bilateral aorto-subclavian bypass was performed in a male with upper limb, exercise-induced vertigo.

RESULTS

Postoperatively symptomatic improvement paralleled an increase in brachial systolic arterial blood pressure readings.

CONCLUSION

Bypass grafting is the more durable option for subclavian artery occlusion, as angioplasty with or without stenting is associated with a higher rate of late stenosis.

Preoperative treatment with recombinant human growth hormone prevents ischemia reperfusion-induced diaphragmatic dysfunction

BACKGROUND

Respiratory complications continue to be a major cause of morbidity and mortality following major vascular surgery. The recent UK Small Aneurysm Trial cited preoperative respiratory function as the major predictor of outcome following elective aortic surgery.

AIM

The aim of this study was to investigate the effect of aortic clamping and revascularization on diaphragmatic muscle function in a small animal model and to evaluate the role of preoperative treatment with recombinant human growth hormone (rhGH) in preventing diaphragmatic muscle dysfunction.

METHODS

Male Sprague-Dawley rats (n = 18) were randomized into one of three groups: control (n = 6) underwent laparotomy only; IR (n = 6) had a laparotomy with infrarenal cross-clamping for 30 min followed by lower torso revascularization for 2 h; IR + rhGH (n = 6) were treated with rhGH (Genotropin 0.3 IU/kg/day) for 5 days before laparotomy and aortic cross-clamping for 30 min followed by lower torso revascularization for 2 h. Diaphragmatic muscle contractile function was assessed ex vivo using electrical field stimulation in a tissue bath.

RESULTS

Two hours of IR injury resulted in a significant impairment in diaphragmatic twitch (Control, 242.01 + 38.45 g; IR, 108.55 + 7.15 g). This impairment was prevented by pretreatment with rhGH (rhGH, 319.14 + 30.71 g; P < 0.01). Tetanic function was also significantly impaired by ischemia reperfusion injury (control, 605 + 77.63 g; IR, 228.12 + 14.38 g). Again, pretreatment with rhGH prevented this deterioration (IR + rhGH, 704.39 + 45.69 g; P < 0.05) compared with controls.

CONCLUSION

The results of this study suggest that preoperative administration of rhGH may have a role in preventing the diaphragmatic dysfunction associated with infrarenal aortic cross-clamping and revascularization.

Carotid Stump Syndrome: Outcome from Surgical Management

OBJECTIVES

in patients with occluded internal carotid arteries the carotid stump is a potential source of microemboli resulting in the persistence of retinal or cerebral ischaemic symptoms. We report 25 patients who had persistent cerebral and retinal ischaemic symptoms with an occluded ipsilateral ICA and a carotid stump who underwent surgical exclusion of the stump.

METHODS

between January 1988 and January 1998, 332 patients underwent carotid endarterectomy. Twenty-five patients (20 males: five females; mean age 58.9 (range 44-78 years)) had carotid stump exclusion. Indications for surgery were transient ischaemic attack (22), amaurosis fugax (eight) and cerebrovascular accident (13). Three patients had undergone contralateral carotid endarterectomy and 12 had significant contralateral stenosis. Twenty patients were being treated with aspirin and four with warfarin at the time of presentation.

RESULTS

the diagnosis of carotid stump was made in 22 patients by angiography. In the remaining three patients duplex alone was diagnostic in two patients. In the third case duplex was combined with magnetic resonance angiography (MRA) to confirm the diagnosis. Stump exclusion was carried out by oversewing the ICA origin. All but one patient remained symptom free at follow-up.

CONCLUSION

carotid stump syndrome should be considered as a likely clinical entity in patients with an occluded ICA and persisting cerebral and retinal microembolic symptoms. Surgical exclusion of the carotid stump is a safe and effective method of treatment.

Management of head injury in a regional hospital

BACKGROUND

Concern about delay in the treatment of serious head injury may result in unnecessary transfer to neurosurgical units for scanning and neurosurgical assessment.

AIMS

This study assessed the management of head injuries in a regional hospital with computed tomographic (CT) and 'image-link' facilities allowing instantaneous transmission of CT scans to the regional neurosurgical unit for specialist assessment.

METHODS

A retrospective study was carried out of all head injuries presenting to Limerick Regional General Hospital in a single year. Data gathered included mechanism of injury, mode of transfer, requirement for admission and length of stay. Neurological status was assessed using the Glasgow Coma Scale (GCS) and functional status using the Glasgow Outcome Scale.

RESULTS

Between January and December 1995, 1,564 patients presented with head injuries to the accident and emergency (A/E) department of Limerick Regional General Hospital. Twenty (1%) were dead on arrival, 12% required hospital admission and the remainder were discharged after assessment. Seventy-six per cent were males and 74% under 40 years of age. Among the 194 patients requiring hospital admission, 14% had a skull fracture and 22 had a severe head injury. CT brain scans were performed in 43 patients and were abnormal in 42%. On the basis of CT and clinical findings, six patients were transferred immediately for a neurosurgical procedure and one was transferred later following clinical deterioration.

CONCLUSIONS

A CT scan and image-link facility permitting remote neurosurgical advice allows the majority of patients with head injury to be safely managed in well-equipped regional units without onsite neurosurgical expertise.

The value of metastatic screening in early primary breast cancer

Up to 25 per cent of patients presenting with "early" breast cancer subsequently develop distant metastases indicating that this group must have occult disseminated disease when initially evaluated. Routine pre-operative haematological and radiological investigation is recommended in order to identify these patients and alter their management accordingly. The aim of this study was to examine the outcome of a pre-operative metastatic screening programme in patients presenting with early breast cancer. Eighty-two patients underwent surgery for stage I-II breast cancer over a 5 yr period from 1990-1995. Before surgery all patients underwent screening tests for metastatic disease. These included a full blood count, liver function tests, chest x-ray, skeletal survey and abdominal ultrasound. Of the 82 patients, metastatic screening significantly altered management in only 1 patient who was found to have asymptomatic lymphangitis carcinomatosa on chest x-ray. The results of this study suggest that the number of patients restaged by screening for metastatic breast cancer may be small and questions the necessity for its routine use in the management of early primary breast cancer.

Nutritional, respiratory, and psychological effects of recombinant human growth hormone in patients undergoing abdominal aortic aneurysm repair

BACKGROUND

Recombinant human growth hormone (rhGH) has been shown to have powerful anabolic effects and to reduce or even prevent nitrogen catabolism in stressed patients. The effects of rhGH on functional parameters are less clearly defined. The aim of this study was to assess the effects of perioperative rhGH on nutritional markers, skeletal muscle function, and psychological well-being in patients undergoing infrarenal, abdominal aortic aneurysm repair.

METHODS

Thirty-three patients undergoing elective infrarenal abdominal aortic aneurysm repair were randomized to one of three groups: (1) control (n = 12): placebo for 6 days before and after surgery; (2) preop + postop (n = 10): rhGH (Genotropin; Pharmacia Ltd, Uppsala, Sweden) 0.3 IU/kg/d for 6 days before and after surgery; and (3) postop (n = 11): placebo for 6 days before and rhGH 0.3 IU/kg/d for 6 days after surgery. Patients were assessed on days -7 and -1 before surgery and days 7, 14, and 60 after surgery.

RESULTS

Administration of rhGH resulted in increased insulin-like growth factor 1 levels, the increase being significantly more marked in the group given rhGH preoperatively. Preoperative and postoperative rhGH reduced the postoperative decrease in both serum transferrin and grip strength at day 7 by 30% and 70%, respectively. Postoperative respiratory function and arterial oxygenation also were improved, with significant differences in arterial oxygenation between rhGH-treated and untreated groups. No difference in mood was seen between groups after surgery, nor was there any difference between subjective assessment of fatigue scores between groups.

CONCLUSIONS

This pilot study indicates that rhGH administered preoperatively has beneficial effects on skeletal muscle and respiratory function and may be more useful than postoperative rhGH administration alone.

The effects of recombinant human growth hormone on cardiopulmonary function in elective abdominal aortic aneurysm repair

OBJECTIVES

Cardiorespiratory complications are the predominant source of morbidity in patients undergoing major surgery. Recombinant human growth hormone (rhGH) has previously been shown to be effective in improving respiratory and cardiac function in compromised patients.

DESIGN

The aim of this study was to assess the effects of perioperative rhGH on cardiac function in 33 patients undergoing elective infrarenal abdominal aortic aneurysm repair.

METHODS

Patients were randomised to one of three groups: placebo for 6 days before and after surgery (control, n = 12); genotropin (GH) 0.3 units/kg/day for 6 days before and after surgery (pre and postop GH, n = 10) and placebo for 6 days before and GH (0.3 units/kg/day) for 6 days after surgery (postop EH, n = 11). Patients were assessed on days 7 and 1 before and days 7, 14 and 50 after operation. Intraoperative cardiac index (CI) was measured after induction of anaesthesia, before and after aortic cross-clamping, after aortic unclamping and at the end of surgery.

RESULTS

Pretreatment with GH resulted in a significantly higher heart rate during surgery and was associated with a trend towards higher cardiac index (CI) (p < 0.067) at all stages of surgery. Mean arterial blood pressure at the stage of aortic unclamping was significantly higher in patients treated with GH preoperatively.

CONCLUSIONS

Larger studies are required to evaluate the beneficial effects of GH in aortic surgery. However, data from this pilot study suggests that perioperative GH administration may result in improved cardiac performance during aortic surgery.

Quality of life following repair of ruptured and elective abdominal aortic aneurysms

OBJECTIVE

To find out whether patients undergoing repair of ruptured abdominal aortic aneurysms (AAA) had more emotional problems and limitations of lifestyle than those listed for elective resection.

DESIGN

Retrospective study

SETTING

Teaching hospital, Eire. SUBJETS: 28 patients, 14 in each group, matched for age, sex, duration of stay in the intensive care unit (ICU), hospital stay postoperatively, and length of time since operation.

INTERVENTIONS

Application of structured questionnaire.

MAIN OUTCOME MEASURES

Emotional problems, mobility, activities of daily living, ability to sleep, degree of psychological stress, presence of symptoms, and Rosser index to measure quality of life (QoL).

RESULTS

There were no significant differences between the groups in any measure.

CONCLUSIONS

Patients have few emotional difficulties or disturbances of QoL after emergency or elective repair of AAA. Survivors after repair of ruptured AAA can expect as good a quality of life as those operated on electively. These results support an aggressive approach to the treatment of ruptured AAA.

Evaluation and application of the Cornell Net Carbohydrate and Protein System for dairy cows fed diets based on pasture

This study evaluated the Cornell Net Carbohydrate and Protein System for dairy cows consuming diets based on pasture, assessed the sensitivity of the model to critical inputs, and demonstrated application opportunities. Data were obtained from four grazing experiments and four indoor pasture feeding experiments (25 dietary treatments) involving dairy cows in New Zealand and the US. The model provided a reasonably good estimate of changes in body condition score (r2 = 0.78; slope not significantly different from 1), estimated energy balance (r2 = 0.76; slope not significantly different from 1), blood urea N (r2 = 0.94; underprediction bias of 0.5%), microbial N flow (r2 = 0.88; slope not significantly different from 1), and milk production. The model underpredicted dry matter intake (r2 = 0.80; 13% bias) and overpredicted ruminal pH (r2 = 0.47; 1.7% bias). Predicted milk production was especially sensitive to changes in pasture lignin content, effective fiber, rate of fiber digestion, and amino acid composition of ruminal microbes. Milk production was first-limited by the supply of metabolizable energy when only high quality pasture was fed, but specific amino acids limited milk production when more than 20% of the diet consisted of a grain supplement. These results indicate that the Cornell Net Carbohydrate and Protein System can be used for dairy cows in a grazing system to make realistic predictions of performance.

An "all comers" policy for ruptured abdominal aortic aneurysms: how can results be improved?

OBJECTIVE

To review our experience of a non-selective policy for the treatment of ruptured abdominal aortic aneurysm to see if the policy was justified, and to identify any preoperative risk factors that adversely influenced outcome.

DESIGN

Retrospective study.

SETTING

Teaching hospital, Republic of Ireland.

SUBJECTS

258 patients admitted with abdominal aortic aneurysms between January 1982 and December 1993.

INTERVENTIONS

Definitive surgical treatment.

MAIN OUTCOME MEASURES

Morbidity, mortality, and risk factors.

RESULTS

In-hospital mortality for all patients was 43% (110/258). Overall, women did worse than men (28/44, 64%, died, compared with 96/214, 45%, p=0.03). The mortality among patients over the age of 80 (23/45, 51%) was not significantly different from that among younger patients (97/202, 48%). Blood pressure, platelet count, and haemoglobin concentration were all significantly lower preoperatively among those who died (p < 0.05).

CONCLUSIONS

Age alone cannot be used to justify witholding definitive surgical treatment. Treatment should be aimed towards reversing haematological and haemodynamic abnormalities preoperatively to try to improve outcome.

Ruptured abdominal aortic aneurysm--can treatment costs and outcomes be predicted by using clinical or physiological parameters?

Mortality rates for patients undergoing surgery for ruptured abdominal aortic aneurysm (RAAA) remain high. The high cost of providing care for these patients mandates that proposed treatment protocols be evaluated for their cost-effectiveness. This study assessed costs related to outcome in different groups of patients with RAAA. From July 1987 to December 1993, 140 patients underwent emergency surgery for RAAA. Complete data on preoperative haemodynamic status, blood transfusion requirements, intensive care unit (ICU) stay and other hospital costs was available for 94 patients. Seventy-seven males (mean age 71.6(6)) and 17 females (mean age 77.2(6)) underwent surgery. Known risk factors including age (< or > 70 years), shock on admission (systolic blood pressure (BP) < or > 90 mm Hg), sex, and acute renal failure were analysed. For the purpose of comparison, costs (Pounds) were assessed by the ESRI (Economic and Social Research Institute of Ireland) based on 1992 prices. The overall survival rate was 48%: 53% among males and 24% among females (p < 0.05, Chi-squared test). In addition to having a significantly worse outcome than males, female patients with RAAA also had longer hospital and ICU stays and this was reflected in significantly greater expenditure. Similarly, male patients > 70 years old presenting with haemodynamic instability had significantly longer hospital and ICU stays than younger male patients. The average cost per RAAA survival (12,945 Pounds) in this series is not prohibitive, and the greater cost in high risk groups should not discourage intervention.

Pre-operative neutrophil and monocyte activation state predicts post-operative neutrophil and monocyte function

OBJECTIVE

To find out if the in vitro responses of neutrophils (PMN) and monocytes preoperatively can predict their activation postoperatively.

DESIGN

Prospective open study.

SETTING

Teaching hospital, Ireland.

SUBJECTS

46 Patients (32 men, 14 women, mean age 65 years, range 33-85) who were to undergo elective major vascular or gastrointestinal operations for benign (n = 18) or malignant (n = 28) diseases.

INTERVENTIONS

Measurement by flow cytometry of functional (PMN and monocyte respiratory burst activity) and phenotypic (expression of PMN CD 11b adhesion receptors and monocyte CD14 receptors) markers of activation.

MAIN OUTCOME MEASURES

Correlation between mean channel fluorescence (MCF) preoperatively and postoperatively.

RESULTS

In 24 patients PMN respiratory burst activity was increased before operation and had decreased significantly (p < 0.01) on postoperative day 1 (high responders group). In the remaining 22 patients (low responders group) respiratory burst activity was low before operation and had increased significantly (p < 0.05) on postoperative day 1. PMN CD 11b activity followed a similar trend. Monocyte activity responded similarly (in the high group mean (SEM) MCF preoperatively was 69.14 (13.15) compared with 58.23 (10.8) on day 1, and in the low group the corresponding figures were 38.5 (7.01) and 8.43 (5.2). Expression of CD14 did not differ between the groups and was less postoperatively than preoperatively. The groups did not differ in age, sex, APACHE 11 scores, smoking habits or types of disease and there was no major infective complications in either group.

CONCLUSION

There are two distinct patterns of PMN and monocyte responses to injury that are independant of age, sex and severity of operation. These may be associated with the degree of stress preoperatively or with genetic factors.

Plasma factors augment neutrophil and endothelial cell activation during aortic surgery

Lung injury following reperfusion results from endothelial damage caused by release of cytotoxic products by activated neutrophils (PMN) in the pulmonary microvasculature. This process is facilitated by the release of pro-inflammatory cytokines and arachidonic metabolites following the outset of reperfusion. This study aimed to evaluate the effect of plasma obtained before and after revascularisation on neutrophil and endothelial cell activation. Plasma (IR-plasma) was obtained from venous blood samples taken before and during aortic cross-clamping, and 5, 40 and 60 min following clamp removal in seven patients undergoing elective infrarenal aortic aneurysm resection. PMN from healthy volunteers (n = 5) were incubated with these plasma samples or with fMLP (N-formylmethionyl-leucyl-phenylalanine) as positive control for 30 min and assessed flow-cytometrically for CD11b expression. Human endothelial cells (ECV-304) were incubated with IR plasma for 2, 4 and 6 h or with tumour necrosis factor (TNF) (20 ng/ml) as positive control and assessed for ICAM-1 expression. Incubation with IR plasma resulted in a significant increase from pre-clamp in PMN CD11b expression. A similar trend was seen in endothelial cell ICAM-1 expression following 2 h incubation. These results indicate that reperfusion-induced endothelial dysfunction may be mediated by plasma factors released upon revascularisation which facilitate neutrophil-endothelial interaction through up-regulation of adhesion receptor expression.

Immunological and physiological responses to aortic surgery: effect of reperfusion on neutrophil and monocyte activation and pulmonary function

BACKGROUND

The aims of this study were to evaluate the effects of aortic clamping and unclamping on neutrophil and monocyte activation and release of plasma mediators in 20 patients undergoing elective aortic aneurysm surgery, and to correlate these findings with pulmonary haemodynamics and gas exchange.

METHODS

Simultaneous arterial and mixed venous samples were obtained during and after aortic clamping and unclamping.

RESULTS

Neutrophil respiratory burst activity in mixed venous samples increased significantly during the period of aortic clamping. An initial increase in neutrophil CD11b expression in venous blood 5 min after clamp removal was followed by a significant decrease in level of expression. Plasma tumour necrosis factor levels increased at the end of the cross-clamp period and reached a maximum 60 min following reperfusion. There was a significant and sustained rise in plasma thromboxane B2 levels following clamp removal. This increase correlated with the development of increased pulmonary vascular resistance.

CONCLUSION

This study confirms the central role played by activated neutrophils in the early stages of reperfusion injury and also suggests a role for plasma mediators in mediating cardiopulmonary dysfunction during major vascular surgery.

Differential effects of lower limb revascularisation on organ injury and the role of the amino acid taurine

Lower torso revascularisation following ischaemia results in a systemic inflammatory response. Endothelial barrier function is disrupted by neutrophil-derived proteases and oxidants. Taurine, an amino acid found in large quantities in neutrophils, is a powerful endogeneous anti-oxidant. The aims of this study were to investigate the systemic effects of reperfusion following lower limb revascularisation and to evaluate the role of taurine administration in preventing this injury. A rat model of aortic occlusion (30 min) followed by 2 h of reperfusion was used. Animals were randomised to one of three groups (n = 10 per group): control; ischaemia reperfusion untreated (IR) and taurine-treated. Taurine (4% solution) was administrated orally for 48 h prior to the experiment. Neutrophil infiltration and microvascular permeability were assessed by measuring tissue myeloperoxidase activity and wet/dry weights respectively in lung, liver, kidney, and in cardiac and skeletal muscle. Statistical analysis was by means of analysis of variance (ANOVA). Reperfusion resulted in pulmonary and renal microvascular injury as assessed by organ oedema. Hepatic tissue, skeletal and cardiac muscle were unaffected by lower limb revascularisation. Taurine was effective in preventing neutrophil-mediated pulmonary but not renal microvascular injury. These data suggest that, whilst reperfusion-induced pulmonary injury is predominantly neutrophil-mediated, agents other than neutrophil-derived oxidative metabolites, capable of independently causing organ injury through direct endothelial damage, are produced during reperfusion.

149 consecutive thyroid operations--indications, technique and outcome

One hundred and forty nine patients underwent thyroid and parathyroid surgery over a nine year period. The most common indications for surgery were the presence of a solitary thyroid nodule (56%) or the onset of pressure symptoms (30%). Carcinoma was found in 7.4% of cases. Wound complications occurred in 5%. The permanent nerve injury rate was 0.67%. The incidence of permanent hypothyroidism after surgery was 4%. No patients developed permanent hypoparathyroidism.

Glyceryl trinitrate prevents neutrophil activation but not thromboxane release following ischaemia-reperfusion injury

The aim of this study was to determine whether glyceryl trinitrate (GTN) has a protective effect on neutrophil-mediated lung injury in a model of aortic occlusion (30 min) and reperfusion (120 min). Sprague-Dawley rats were randomized into control (n = 11), ischaemia-reperfusion (IR) (n = 12), and IR treated with GTN (2 micrograms kg-1 min-1) during reperfusion (n = 10). Myeloperoxidase (MPO) activity measured pulmonary neutrophil influx. Pulmonary endothelial permeability was measured by wet:dry weight ratio, bronchoalveolar lavage (BAL) protein and neutrophil counts. Neutrophil superoxide release was measured by flow cytometry in a further IR versus GTN experiment (n = 6 in each group). The significant increase in MPO activity produced by IR to a level of 7.99 units g-1 was prevented by GTN which reduced the level to 4.73 units g-1. The increase in pulmonary microvascular leakage after reperfusion was also prevented by GTN: BAL protein without GTN was 992 micrograms ml-1 and with GTN 579 micrograms ml-1; BAL neutrophil count without GTN was 3219 cells mm-3 and with GTN 820 cells mm-3; the wet:dry lung weight ratio without GTN was 3.8 and with GTN 3.3. Neutrophil superoxide release increased significantly after 40 min of reperfusion in the untreated IR group (P < 0.05). This increase was prevented in the GTN-treated group. GTN administration had no effect on plasma thromboxane production during revascularization. These data suggest that GTN administration during the reperfusion phase has the potential to decrease pulmonary microvascular injury.

Changing trends in acute peptic ulcer surgery in a district surgical unit

Despite changes in management and the advances in therapeutics, surgeons are still required to treat the complications of peptic ulceration. A retrospective review of all open surgical interventions for complications of peptic ulcer disease between January 1983 and December 1993 was carried out. There were no exclusion criteria. Open gastric surgery accounted for 3% of all inpatient surgical procedures and 13% of all the major operations. There were 341 adult and 132 paediatric procedures performed in the 11 year period. Acute gastric procedures accounted for 34% of major gastric surgery in this district unit. 76 perforated ulcers and 39 bleeding ulcers required surgery. 38% of the patients were over 70 years. The perioperative mortality was 13.9% (4% for those under 70 years). The overall morbidity rate was 71% and procedure-related morbidity rate was 17%. Acute gastric surgery has a very high inpatient morbidity and is associated with a significant mortality particularly in elderly patients.

Prediction of ruminal volatile fatty acids and pH within the net carbohydrate and protein system

A steady-state model of the production, absorption, passage, and concentration of ruminal VFA and pH is developed from published literature data and is structured to use the feed descriptions and inputs from the net carbohydrate and protein system. Included are the effects of pH on growth rate and yield of structural and non-structural carbohydrate-fermenting bacteria; production of acetate, propionate, butyrate, lactate, and methane; conversion of lactate to VFA; ruminal absorption of acids; and prediction of ruminal pH from dietary measures and from ruminal buffering and acidity. The root mean square error of predicted total VFA concentration was 12 mM. Individual VFA fractions were inadequately predicted. In a review of literature data, effective NDF (eNDF) provided a better correlation with ruminal pH than forage or NDF. Digestion rate of NDF remained at normal levels above pH 6.2, which corresponds to a minimum eNDF of 20% of dietary DM. Further research is needed to determine the individual VFA produced from carbohydrate fractions at various pH, the appropriateness of partitioning the starch and pectin carbohydrate pool into slowly and rapidly degraded fractions, and the effect on microbial yield, total tract digestibility, and predicted energy values of feeds.

Application of the Cornell Net Carbohydrate and Protein model for cattle consuming forages

Accurate prediction of forage biological values and performance with animals fed forages requires accurately accounting for factors that influence animal requirements and feedstuff utilization. The Cornell Net Carbohydrate and Protein System (CNCPS) is an application model that uses a combination of mechanistic and empirical approaches to account for the effects of variation in animal factors and feed carbohydrate and protein fractions on animal performance. Thus, accurate animal and environmental descriptions, DMI, feed carbohydrate, and protein fractions and their digestion rates are required inputs. In 25 growth periods with calves fed high-forage diets, the CNCPS accounted for 74, 81, and 83%, respectively, of the variation in ADG predicted to be supported by the ME, metabolizable protein, and essential amino acid intake, the first-limiting of all three accounting for 81% of the variation with a -1% bias. Thus, the CNCPS can be used to accurately describe forage quality and the effects of changes in forage composition on animal performance. The model was sensitive to variations in NDF, CP, protein solubility, NDF and starch digestion rates, feed and microbial amino acid composition, maintenance protein requirement, body protein amino acid content, and the coefficient of efficiency of use of absorbed protein. Analysis of several trials indicates an improved efficiency of ME use with improved amino acid balances. Uses of the CNCPS discussed include interpreting, planning and applying research, teaching, developing tables of requirements and biological values for feeds, complex nutritional accounting, and predicting performance and profits.

Predicting amino acid adequacy of diets fed to Holstein steers

The Cornell Net Carbohydrate and Protein System (CNCPS) and NRC (1985) models were evaluated for accuracy in predicting metabolizable protein (MP) and essential amino acid (EAA) allowable ADG, using chemical body and feed composition data from feeding trials with Holstein steers. Nine Holstein steers (113 to 200 kg) were slaughtered and determined to have the following whole-body essential amino acid composition of (grams/100 grams of protein): arginine, 5.94; histidine, 2.07; isoleucine, 2.28; leucine, 5.72; lysine, 5.81; methionine, 1.99; phenylalanine, 3.04; threonine, 3.52; tryptophan, .57; and valine, 3.32. The NRC and CNCPS were then tested against data from 25 feeding periods, each representing the 56-d growth of 10 Holstein steers (mean BW of 162 kg), to determine their ability to predict the gain allowed by the supply of MP and the first-limiting EAA. The NRC (1985) system accounted for 46% of the variation in MP allowable gain, with an average bias of -30%. The CNCPS accounted for 87 and 73% of the variation in MP and EAA allowable gain, with a bias of 8 and 5%, respectively. The bias was reduced to 3% (R2 of .82) when ADG was predicted by the factor (ME, MP, or EAA) first-limiting ADG.