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1.  Development of adaptive pneumatic tourniquet systems based on minimal inflation pressure for upper limb surgeries 
Background
Pneumatic tourniquets are medical devices that occlude blood flow to distal part of extremities and are commonly used in upper limb surgeries to provide a dry, clean and bloodless field. To decrease pressure-related injuries and potential risk of complications subjected to the high inflation pressure of pneumatic tourniquet, minimal inflation pressures are recommended.
Methods
A new occlusion pressure mathematical model for the upper limb was established based on the correlation analysis between several possible influencing parameters and the minimal pneumatic tourniquet pressure at which the peripheral pulse disappeared was recorded using a digital plethysmograph. A prototype of an adaptive pneumatic tourniquet which automatically varies the pressure in the tourniquet cuff according to the above prediction model was developed for the upper limb which used the lowest possible inflation pressure to achieve occlusion. The prototype comprises a blood pressure monitoring module, an inflatable tourniquet cuff, and a pressure relief mechanism to maintain an optimal cuff inflation pressure. Simulation experiments were conducted to verify the function and stability of the designed adaptive pneumatic tourniquet and clinical experiments using volunteers were undertaken to evaluate the performance of the prototype design in achieving adequate haemostasis in the upper limb.
Results
Results demonstrated that the mean arterial occlusion pressure was 152.3 ± 16.7 mmHg, obviously below the 250 to 300 mmHg previously recommended (J Bone Joint Surg Br 68:625-628, 1986 and Arthroscopy 11:307–311, 1995).
Conclusions
In conclusion, this adaptive method and apparatus which can provide minimal inflation pressure may be a clinically practical alternative for upper limb surgery performed with pneumatic tourniquets.
doi:10.1186/1475-925X-12-92
PMCID: PMC3848664  PMID: 24053348
Pneumatic tourniquet; Upper limb; Arterial occlusion pressure; Microprocessor
2.  Tourniquet use in upper limb surgery 
Hand (New York, N.Y.)  2010;6(2):165-173.
Tourniquets are compressive devices that occlude venous and arterial blood flow to limbs and are commonly used in upper limb surgery. With the potential risk of complications, there is some debate as to whether tourniquets should continue to be routinely used. In this review, we first look at the different designs, principles, and practical considerations associated with the use of tourniquets in the upper limb. The modern pneumatic tourniquet has many design features that enhance its safety profile. Current literature suggests that the risk of tourniquet-related complications can be significantly reduced by selecting cuff inflation pressures based on the limb occlusion pressure, and by a better understanding of the actual level of pressure within the soft tissue, and the effects of cuff width and contour. The evidence behind tourniquet time, placement, and limb exsanguination is also discussed as well as special considerations in patients with diabetes mellitus, hypertension, vascular calcification, sickle cell disease and obesity. We also provide an evidence-based review of the variety of local and systemic complications that may arise from the use of upper limb tourniquets including pain, leakage, and nerve, muscle, and skin injuries. The evidence in the literature suggests that upper limb tourniquets are beneficial in promoting optimum surgical conditions and modern tourniquet use is associated with a low rate of adverse events. With the improvement in knowledge and technology, the incidence of adverse events should continue to decrease. We recommend the use of tourniquets in upper limb surgery where no contraindications exist.
doi:10.1007/s11552-010-9312-6
PMCID: PMC3092892  PMID: 22654699
Tourniquet; Upper limb; Limb occlusion pressure; Complications
3.  Effect of different cuff widths on the motor nerve conduction of the median nerve: an experimental study 
Background
A bloodless operative field is considered mandatory for most surgical procedures on the upper and lower extremity. This is accomplished by using either an Esmarch bandage or a pneumatic tourniquet, but a number of complications are associated with both. Nerve palsy is one of the most frequently encountered complications of this procedure. Wider cuffs have been found to cause reduced risk of tourniquet induced injury to the underlying soft tissues than the narrower ones due to the fact that lower occlusion pressures are caused by the former. To address and investigate this question, conduction in the median nerve has been measured proximal to tourniquet as well as distal to the tourniquet. Parameters of nerve conduction measured are nerve conduction velocity, latency and amplitude.
Methods
Sphygmomanometer cuffs with widths 14 cm and 7 cm were applied to the upper extremities of 20 healthy, normotensive volunteers (9 males and 11 females with age ranging from 22 to 27). Systolic blood pressure was measured first and then the cuff was inflated to about 20–30 mm Hg above it and was kept inflated for 15 minutes. Recordings were done prior to, for the period of tourniquet inflation, and following release of the tourniquet.
Results
Nerve conduction was found to be more severely affected by the 14 cm cuff than the 7 cm cuff.
Conclusion
Wider cuffs resulted in more severe changes in the nerve. This brings us to the conclusion that though lower inflation pressures are required for the occlusion of the blood supply using wider cuffs, the nerve conduction is more severely affected by the wider ones. Both electrophysiological changes and occlusion pressure should be kept in mind while choosing the width of the cuff.
doi:10.1186/1749-799X-3-1
PMCID: PMC2235835  PMID: 18182119
4.  Clinical use of a new tourniquet system for foot and ankle surgery 
International Orthopaedics  2009;34(3):355-359.
This study reports the results of the clinical use of a new tourniquet system for surgery of foot and ankle that can determine tourniquet pressure in synchrony with systolic blood pressure (SBP). We prospectively applied additional pressure of 100 mmHg based on the SBP recorded before the skin incision in 100 consecutive procedures. There were 34 open reduction internal fixation procedures, 26 lateral colateral ligament repair or reconstruction, 16 Achilles tendon repairs, nine arthroscopic procedures such as removal of loose body or accessory bone and synovectomy, seven corrective osteotomy and eight others such as removal of tumour, ankle fusion, and bone graft. The average initial tourniquet pressure was 211 mmHg. The average maximum SBP change during surgery was 28 mmHg. All cases maintained an excellent operative field without measurable bleeding and there were no postoperative complications. Fifty-five cases had a lower intra-operative SBP than the initial value. Since a tourniquet should be applied at the lowest pressure possible for maintaining a bloodless surgical field, the new system appears to be practical and reasonable, as compared to conventional tourniquets, which maintain the initial pressure.
doi:10.1007/s00264-009-0804-3
PMCID: PMC2899285  PMID: 19455329
5.  Relation between preoperative autonomic function and blood pressure change after tourniquet deflation during total knee replacement arthroplasty 
Korean Journal of Anesthesiology  2012;62(2):154-160.
Background
Tourniquets are used to provide a bloodless surgical field for extremities. Hypotension due to vasodilation and bleeding after tourniquet deflation is a common event. Hemodynamic stability is modulated by the autonomic nervous system (ANS). Heart rate variability (HRV) is a sensitive method for detecting individuals who may be at risk of hemodynamic instability during general anesthesia. The purpose of this study was to investigate ANS function to predict hypotension after tourniquet deflation.
Methods
Eighty-six patients who underwent total knee replacement arthroplasty (TKRA) were studied. HRV, systolic blood pressure variability (SBPV) and baroreflex sensitivity (BRS) were analyzed. We assigned two groups depending on the lowest systolic blood pressure (SBP) or mean BP (MBP) after tourniquet release (Group H; SBP < 80 mmHg or MBP < 60 mmHg, Group S; SBP > 80 mmHg and MBP > 60 mmHg).
Results
Fifteen patients developed severe hypotension and ten patients were treated with ephedrine. Of the parameters of HRV, SBPV, and BRS, only BRSSEQ was significant being low in Group H. BRS and high-frequency SBPV were correlated with the degree of MBP change after tourniquet deflation.
Conclusions
Preoperative low BRS is associated with hypotension after tourniquet deflation, suggesting the importance of baroreflex regulation for intraoperative hemodynamic stability.
doi:10.4097/kjae.2012.62.2.154
PMCID: PMC3284738  PMID: 22379571
Baroreflex sensitivity; Heart rate variability; Hypotension; Systolic blood pressure variability; Tourniquet deflation
6.  The efficacy of tourniquet assisted total knee arthroplasty on patient-reported and performance-based physical function: a randomized controlled trial protocol 
Background
Surgical treatment of osteoarthritis with total knee arthroplasty (TKA) usually takes place in a complete bloodless field using a tourniquet. However, doing the surgery without a tourniquet may reduce muscle damage, post-surgery pain and led to improved functional rehabilitation and mobilization.
Methods/Design
A prospective, blinded, parallel-group, controlled superiority trial, with balanced randomization [1:1]. Patients aged 50 or older eligible for primary TKA for osteoarthritis will be consecutively recruited from Department of Orthopedic Surgery and Traumatology, Odense University Hospital, Denmark. A total of 80 patients will be randomly allocated to TKA with or without tourniquet application providing 40 patients for each of the two treatment arms. The tourniquet assisted TKA group will have an automatic, micro-processor-based pneumatic tourniquet inflated around the thigh during surgery. The non-tourniquet assisted TKA group will have surgery performed without application of a tourniquet. The primary aim is to compare tourniquet assisted to non-tourniquet assisted TKA on patient-reported physical function (KOOS-ADL). The secondary aim is to compare post-surgery pain, function in sports and recreation, quality of life, and performance-based physical function. The explorative outcomes include; use of pain medication, single-fiber muscle damage, and changes in mechanical muscle function. The primary endpoint will be at 3-months following surgical treatment, and the time-point for analysis of the primary outcome. However, follow-up will continue up to 1 year, and provide medium-term results. The treatment effect (difference in KOOS-ADL) will be analyzed using a random effects regression model, crude and adjusted results will be reported, if needed. Analyses will be based on the intention-to-treat (ITT). Subsequent per-protocol analysis may be necessary in the event of a substantial number of patients (> 15%) being lost during follow-up. The number needed to treat (NNT) for a positive effect of treatment (>10 points on KOOS-ADL) will be reported.
Discussion
This is the first randomized clinical trial comparing the efficacy of tourniquet assisted TKA on patient-reported physical function supported by a range of performance-based secondary outcome measures. As such it will provide high quality evidence that may help determine whether tourniquet should be used in future TKA procedures in patients with osteoarthritis of the knee.
Trial registration
ClinicalTrials NCT01891266.
doi:10.1186/1471-2474-15-110
PMCID: PMC3978123  PMID: 24678741
Tourniquet; Total knee arthroplasty; Patient-reported; Performance-based; Physical function
7.  Understanding of intra-operative tourniquets amongst orthopaedic surgeons and theatre staff – a questionnaire study 
INTRODUCTION
Pneumatic tourniquets are used frequently in orthopaedic theatres to provide a bloodless field whilst operating on the extremities. Their use has given rise to complications and preventable damage due to over-pressurisation and prolonged application. We designed a questionnaire to assess the knowledge on tourniquet use among operating department assistants (ODAs) and specialist registrars (SpRs) in orthopaedic surgery.
SUBJECTS AND METHODS
A questionnaire was constructed using set guidelines from the Association of periOperative Registered Nurses (AORN) for recommended practice of tourniquet application. This was distributed to orthopaedic registrars with varying levels of experience and ODAs from five different NHS hospitals. The unpaired, two tailed t-test was used to test for statistical significance of results.
RESULTS
A total of 54 completed questionnaires were collected for analysis. The study population included 29 orthopaedic SpRs and 25 ODAs. The mean score for the orthopaedic SpRs as a group was 41.3% (SD 6.85; range, 29.0–54.8%). The mean score for the ODAs was 46.7% (SD 9.64; range, 23.3–62.9%) with a P-value of 0.024.
CONCLUSIONS
Most surgeons are taught how to use pneumatic tourniquets by their senior colleagues as no formal teaching is given. Most of the complications are infrequent and preventable. However, their consequences can be devastating to the patient with medicolegal implications. Our results show suboptimal knowledge of tourniquets and their use among SpRs and ODAs. This study highlights the need for amendments in training to improve the knowledge and awareness of medical practitioners on the application and use of tourniquets to prevent adverse events and improve patient safety.
doi:10.1308/003588410X1251883644060
PMCID: PMC3080086  PMID: 20223078
Tourniquets; Education; Extremities; Orthopaedics; Ischaemia
8.  Tourniquet-Free Hand Surgery Using the One-per-Mil Tumescent Technique 
Archives of Plastic Surgery  2013;40(2):129-133.
Background
A pneumatic tourniquet is generally used to achieve a bloodless operation field in hand surgery. However, this has changed with tumescent solution-based wide-awake surgery. This study is a preliminary prospective case series study to elaborate the formula and indications of the tumescent technique in hand surgery without a tourniquet.
Methods
Seven patients (age range, 4 months to 37 years) underwent hand or upper extremity surgery for conditions such as nerve palsy, electric burn defect, fingertip injury, contracture, constriction ring syndrome, or acrosyndactyly. A "one-per-mil" tumescent solution (epinephrine 1:1,000,000+20 mg lidocaine/50 mL saline) was used to create a bloodless operating field without a tourniquet. Observation was performed to document the amount of solution injected, the operation field clarity, and the postoperative pain.
Results
The "one per mil" epinephrine solution showed an effective hemostatic effect. The tumescent technique resulted in an almost bloodless operation field in the tendon and in the constriction ring syndrome surgeries, minimal bleeding in the flap and contracture release surgeries, and acceptable bleeding in acrosyndactyly surgery. The amount of solution injected ranged from 5.3 to 60 mL. No patient expressed significant postoperative pain. Flap surgeries showed mixed results. One flap was lost, while the others survived.
Conclusions
Epinephrine 1:1,000,000 in saline solution is a potential replacement for a tourniquet in hand surgery. Further studies are needed to delineate its safety for flap survival.
doi:10.5999/aps.2013.40.2.129
PMCID: PMC3605557  PMID: 23533019
Epinephrine; Lidocaine; Upper extremity
9.  Tourniquet time affects postoperative complications after knee arthroplasty 
International Orthopaedics  2013;37(5):827-832.
Purpose
Pneumatic tourniquets are frequently used in knee arthroplasty surgery. However, there is a lack of evidence to define safe tourniquet time in lower limb surgery. The primary aim of this study was to investigate whether tourniquet time influences the risk of postoperative complications after primary and secondary knee arthroplasty.
Methods
This study was a prospective register study. Since we wanted dispersion in tourniquet time, we included a consecutive series of 577 primary knee arthroplasties, 46 revision knee arthroplasties, and 18 patellar supplementing knee arthroplasties from a clinical audit database over a period of five years. The following postoperative complications were recorded: superficial wound infections, deep wound infections, deep vein thrombosis, pulmonary embolism, nerve injuries, compartment syndrome, cuff pressure injuries, and bandage injuries.
Results
Tourniquet time over 100 minutes was associated with an increased risk of complications after knee arthroplasty surgery (OR 2.2, CI 1.5–3.1). This increase in risk remained after adjusting for cuff pressure, sex, age, American Society of Anesthesiologists (ASA) classification, smoking, diabetes, and surgery indication (OR 2.4, CI 1.6–3.6).
Conclusions
Tourniquet time over 100 minutes increases the risk of complications after knee arthroplasty surgery and special attention is advocated to reduce the tourniquet time.
doi:10.1007/s00264-013-1826-4
PMCID: PMC3631475  PMID: 23417522
10.  The effect of tourniquet deflation on hemodynamics and regional cerebral oxygen saturation in aged patients undergoing total knee replacement surgery 
Korean Journal of Anesthesiology  2012;63(5):425-430.
Background
Inflation and deflation of a pneumatic tourniquet used in total knee replacement surgery induces various changes in patient's hemodynamic and metabolic status, which may result in serious complications, especially in aged patients. Near-infrared spectroscopy (NIRS) is a monitoring device designed to estimate the regional cerebral oxygen saturation. We evaluated the effect of tourniquet deflation on hemodynamics and regional cerebral oxygen saturation in aged patients undergoing total knee replacement surgery, using NIRS.
Methods
Twenty-eight American Society of Anesthesiologists physical status I or II patients, over the age of sixty-five years undergoing total knee replacement surgery, were included. Under general anesthesia, the mean arterial pressure (MAP), heart rate (HR), cardiac output (CO), stroke volume (SV), and regional cerebral oxygen saturation (rSO2) were recorded before induction of anesthesia and every 2 min after tourniquet deflation for 20 min. Arterial blood gas analysis was performed 5 min before, in addition to 0, and 10 min after tourniquet deflation.
Results
The decrease of rSO2 was not significant during 20-min deflation period. MAP, CO and SV showed significant decrease during 2 to 12, 4 to 6 and 2 to 6-min period after tourniquet deflation, respectively (P < 0.05). There was no relationship between a maximal decrease of MAP and rSO2.
Conclusions
In aged patients undergoing total knee replacement surgery under general anesthesia, tourniquet deflation caused significant changes in hemodynamic and metabolic status, but not in regional cerebral oxygen saturation. It is recommended to monitor neurologic status, as well as hemodynamic and metabolic status to avoid serious complications, especially in aged patients.
doi:10.4097/kjae.2012.63.5.425
PMCID: PMC3506852  PMID: 23198036
Aged; Hemodynamics; Near-Infrared spectroscopy; Tourniquet
11.  Tourniquet-Related Iatrogenic Femoral Nerve Palsy after Knee Surgery: Case Report and Review of the Literature 
Case Reports in Orthopedics  2013;2013:368290.
Purpose. Tourniquet-induced nerve injuries have been reported in the literature, but even if electromyography abnormalities in knee surgery are frequent, only two cases of permanent femoral nerve palsies have been reported, both after prolonged tourniquet time. We report a case of tourniquet-related permanent femoral nerve palsy after knee surgery. Case Report. We report a case of a 58-year-old woman who underwent surgical treatment of a patella fracture. Tourniquet was inflated to 310 mmHg for 45 minutes. After surgery, patient complained about paralysis of the quadriceps femoris with inability to extend the knee. Electromyography and nerve conduction study showed a severe axonal neuropathy of the left femoral nerve, without clinical remission after several months. Discussion. Even if complications are not rare, safe duration and pressure for tourniquet use remain a controversy. Nevertheless, subtle clinical lesions of the femoral nerve or even subclinical lesions only detectable by nerve conduction and EMG activity are frequent, so persistent neurologic dysfunction, even if rare, may be an underreported complication of tourniquet application. Elderly persons with muscle atrophy and flaccid, loose skin might be in risk for iatrogenic nerve injury secondary to tourniquet.
doi:10.1155/2013/368290
PMCID: PMC3858884  PMID: 24371536
12.  The effect of sterile versus non-sterile tourniquets on microbiological colonisation in lower limb surgery 
INTRODUCTION
Surgical tourniquets are commonplace in lower limb surgery. Several studies have shown that tourniquets can be a potential source of microbial contamination but have not compared the use of sterile versus non-sterile tourniquets in the same procedures.
METHODS
Patients undergoing elective orthopaedic lower limb surgery were randomised prospectively to use of non-sterile pneumatic tourniquet or sterile elastic exsanguination tourniquet (S-MART™, OHK Medical Devices, Haifa, Israel). Samples were taken from the ties of the non-sterile tourniquet prior to surgery and from the sterile tourniquets at the end of the operation in a sterile fashion. These were then sealed in universal containers and immediately analysed by the microbiology department on agar plates, cultured and incubated.
RESULTS
Thirty-four non-sterile tourniquets were sampled prior to surgical application, twenty-three of which were contaminated with sev-eral different organisms including coagulase-negative Staphylococcus spp, Staphylococcus aureus, Sphingomonas pau-cimobilis, Bacillus spp, and coliforms. Thirty-six sterile tourniquets were used, with no associated contamination.
CONCLUSIONS
There was significant contamination of 68% of orthopaedic surgical tourniquets. These are used regularly in proce-dures involving the placement of prosthesis and metalwork, and can act as a potential source of infection. We recommend the use of sterile single-use disposable tourniquets where possible. The availability of an alternative should now set the new standard of care and we rec-ommend adopting this as a current NICE guideline for control of surgical site infection.
doi:10.1308/147870811X13137608455334
PMCID: PMC3566682  PMID: 22041233
Tourniquet; Equipment contamination; Orthopedic equipment; Lower extremity; Agar plate
13.  Tourniquets in orthopedic surgery 
Indian Journal of Orthopaedics  2012;46(4):377-383.
Tourniquets are commonly used in limb surgeries, be it orthopedic or plastic surgeries. But the inflation pressures, the duration, and release guidelines are still not clear. According to a survey, majority of orthopedic surgeons inflate the tourniquet to fixed pressures for the upper and the lower limbs without considering the baseline blood pressure of the patient on whom the tourniquets are being applied. This review was designed to recall and review the safe use of tourniquets and the various techniques that can be employed to minimize the complications of tourniquet use. Google, science direct, and pubmed were searched for appropriate literature and relevant articles were identified.
doi:10.4103/0019-5413.98824
PMCID: PMC3421924  PMID: 22912509
Tourniquet; orthopaedic surgery; tourniquet and complications
14.  A prospective randomised trial of tourniquet in varicose vein surgery. 
A prospective randomised trial of 50 patients was carried out to assess the autoclavable Lofquist cuff (Boazal, Sweden) as a tourniquet in varicose vein surgery and determine the effect on bleeding, bruising, cosmesis and patient pain and activity. Patients undergoing unilateral long saphenous vein ligation, stripping and avulsions were randomised to tourniquet or no tourniquet. Lofquist cuffs were applied after inflation to 120 mmHg to the upper thigh for the duration of the surgery. Varicose vein grade, duration of surgery, blood loss, extent of bruising at 7 days, pain and activity scores over the first week, and wound complications and cosmetic result at 6 weeks were recorded. Patients' age, sex, and varicose vein grade were similar in the two groups. Peroperative blood loss (median, range) was significantly reduced in the tourniquet group (0 ml, 0-20 ml) compared to the no tourniquet group (125 ml, 20-300; P < 0.01). Operative time and thigh bruising (median, range) were also reduced in the tourniquet group (30 min, 11-47 min; 72 cm2, 30-429 cm2), respectively, compared to the no tourniquet group (37 min, 18-50 min; 179 cm2, 24-669 cm2) both (P < 0.01). There was no difference in pain and activity scores in the two groups and cosmetic results were also similar. The use of the Lofquist cuff tourniquet during varicose vein surgery reduces peroperative blood loss, operative time and postoperative bruising without any obvious drawbacks.
PMCID: PMC2503503  PMID: 10932665
15.  The penile tourniquet 
Asian Journal of Andrology  2013;15(3):364-367.
Tourniquets are commonly used in penile surgery to achieve a bloodless operating field or produce artificial erections intraoperatively. Several techniques have been described, but there is a paucity of data and a lack of guidelines to direct their safe use. In penile surgery, it is the local rather than systemic effects of tourniquet use that are the main concern. Tourniquet time should be kept to a minimum, as the limited data available suggests that reperfusion injury can occur even after short periods of ischaemia. High risk groups such as diabetics and arteriopaths are at particular risk. Further studies are needed to determine safe tourniquet times and pressures.
doi:10.1038/aja.2012.164
PMCID: PMC3739663  PMID: 23542140
hypospadia; ischaemia; penile surgery; reperfusion injury; tourniquet
16.  A Case of Rhabdomyolysis Associated with Use of a Pneumatic Tourniquet during Arthroscopic Knee Surgery 
The common causes of rhabdomyolysis include trauma, hypoxia, drugs, toxins, infections and hyperthermia. Operative insults, including direct trauma and ischemia, have the potential to cause the development of rhabdomyolysis. Pneumatic tourniquets used during arthroscopic knee surgery to prevent blood loss have led to many complications such as nerve paralysis and vascular injuries. Rhabdomyolysis can also be caused by prolonged pneumatic tourniquet application without a midapplication release, and also from an increased application pressure, but the actual incidence of this is low. In order to prevent rhabdomyolysis, the clinicians must be aware of such risks and follow strict guidelines for the application time, the midapplication release and also the inflation pressure. Vigorous hydration and postoperative patient surveillance are helpful to prevent rhabdomyolysis. We have recently experienced a case of rhabdomyolysis after the arthroscopic knee surgery, and the rhabdomyolysis could have been associated with the use of a pneumatic tourniquet.
doi:10.3904/kjim.2010.25.1.105
PMCID: PMC2829407  PMID: 20195412
Rhabdomyolysis; Tourniquets; Kidney failure, acute
17.  A prospective trial of local versus general anaesthesia for arthroscopic surgery of the knee. 
We set out to determine if arthroscopic knee surgery was acceptable to patients and their surgeon when carried out using a local anaesthetic infiltration technique. Patients awaiting arthroscopy were randomly allocated to have either a local or a general anaesthetic. The same surgeon (NPT) carried out all the procedures. The demographic profile was similar in the two groups, as were the diagnosis and the surgical procedures. The only difference between the two groups was that those performed under local anaesthesia did not have a limb tourniquet inflated. The time spent in the theatre suite was similar in each group. This did not include the recovery time in the general anaesthetic group. The duration of the operation was longer in the local anaesthetic group (P = 0.05). A simple 0 to 10 scoring system indicated that patients preferred a local anaesthetic but the surgeon preferred to have the patient asleep (P > 0.05). Those having a local anaesthetic required less physiotherapy (P = 0.025) and more of them returned to work and sport earlier (P = 0.05). We attributed this to not having sustained pressure-induced tissue damage to the thigh muscle as they did not have a tourniquet inflated. We had a 4% failure rate in the local anaesthetic group. Arthroscopic surgery is already a well-established day case procedure and our findings have a financial implication (a saving of 25 pounds per case) as well as identifying a safer technique in the medically unfit. Unfortunately, this technique is not suitable for the investigation and treatment of all knee problems. There are certain constraints, viz the very anxious patient, acute problems, children, larger arthroscopic procedures and the inability to perform an examination under anaesthetic but, overall, it is a useful and effective way of performing a common surgical procedure.
PMCID: PMC2503043  PMID: 9326126
18.  Pulseless electrical activity during electroconvulsive therapy: a case report 
BMC Anesthesiology  2012;12:8.
Background
Arrhythmias resulting in cardiac arrest during electroconvulsive therapy have been reported. Most reported cases of cardiac arrest had asystole as the initial rhythm. Pulseless electrical activity as an initial rhythm of cardiac arrest during electroconvulsive therapy has never been reported. Also, thromboembolism after inflation of pneumatic tourniquet during lower limb surgery has been reported but never following tourniquet inflation during an electroconvulsive therapy.
Case presentation
We report a case involving an 81- year- old female who presented to us for an electroconvulsive therapy for severe depression and developed pulseless electrical activity immediately after electroconvulsive therapy. She was successfully resuscitated and was later found to have bilateral pulmonary emboli with a complete occlusion of the right lower lobe pulmonary artery. The source of embolus was from her left lower extremity deep venous thrombus, which we believe, got dislodged intraoperatively after inflation of pneumatic tourniquet. Our patient not only survived the massive pulmonary embolus, but also showed significant improvement in her mental status compared to her pre-admission level at the time of discharge to a sub-acute rehabilitation centre.
Conclusion
We recommend that patients who are elderly and at high risk of thromboembolism should selectively undergo a preoperative doppler ultrasound for deep venous thrombosis. Also, selective application of tourniquet in the upper limb, to monitor for seizure activity, would reduce the incidence of pulmonary thrombo-embolism as embolic events are significantly less from deep venous thromboses of upper extremities when compared to lower extremities.
doi:10.1186/1471-2253-12-8
PMCID: PMC3403950  PMID: 22650157
ECT; Pulseless electrical activity; Tourniquet; Pulmonary embolism
19.  Silicone ring tourniquet versus pneumatic cuff tourniquet in carpal tunnel release: a randomized comparative study 
Background
The aim of the present study was to compare the pain levels resulting from the use of a silicone ring tourniquet (SRT) to those resulting from the use of a classic pneumatic cuff tourniquet (PT) in patients undergoing carpal tunnel release under local anesthesia.
Materials and methods
Fifty patients that underwent carpal tunnel release under local anesthesia were randomized using the technique of stratified randomization by minimization. A forearm tourniquet was applied: a standard PT was used in 25 patients, and an SRT was used in the other 25 patients (the model of SRT used was selected according to the standard systolic blood pressure). Patient demographics and complications were recorded. Pain levels were assessed with the visual analogue scale and were recorded (a) just after tourniquet application, (b) 5 min after tourniquet application, and (c) just before tourniquet removal.
Results
There was no statistical significant difference in patient demographics between the two groups. The mean tourniquet time was similar for both groups (p = 1.000). The difference between the mean final pain level and the mean initial pain level was statistically significant for the SRT group (p = 0.010) and highly statistically significant for the PT group (p < 0.001). The mean final pain level for the PT group was higher than that for the SRT group (p = 0.043).
Conclusions
According to the findings of this study, in patients who underwent carpal tunnel release under local anesthesia, the pain levels at the end of the operation and those just before the removal of the tourniquet were higher in the PT group than in the SRT group of patients.
doi:10.1007/s10195-012-0223-x
PMCID: PMC3667358  PMID: 23361654
Tourniquet; Pneumatic tourniquet; Silicon ring tourniquet; Tourniquet pain
20.  The effects of a pneumatic tourniquet on blood loss in total knee arthroplasty 
Canadian Journal of Surgery  2001;44(1):33-38.
Objective
In lower-extremity surgery there are significant risks associated with the use of tourniquets. This prospective study was done to assess to what extent these risks may be offset by the potential advantages of tourniquets, namely reductions in blood loss, length of hospital stay and complication rates.
Design
A prospective case study.
Setting
A major urban hospital.
Patients
Sixty-three consecutive patients scheduled for primary cemented total knee arthroplasty (TKA) were blindly randomized into tourniqet (n = 33) and non-tourniquet (n = 30) groups.
Intervention
TKA during which a pneumatic tourniquet was applied or not applied to control blood loss.
Main outcome measures
Perioperative blood loss, operating time, complication rates, hospital stay and transfusion needs.
Results
Differences in the total measured blood loss, intraoperative blood loss and the Hemovac drainage blood loss between the 2 groups were not significantly different (p > 0.25). The calculated total blood loss was actually lower in the non-tourniquet group (p = 0.02). Between the groups there were no statistical differences in surgical time, length of hospital stay, transfusion requirements or rate of complications (although there was a trend to more complications in the tourniquet group (p = 0.06)).
Conclusion
The effectiveness of a pneumatic tourniquet to control blood loss in TKA is questionable.
PMCID: PMC3695181  PMID: 11220796
21.  Distal forearm tourniquet for hand surgery 
International Orthopaedics  2004;28(5):267-269.
To evaluate the usefulness of the tourniquet placed at the distal forearm, 30 patients were operated with the tourniquet set at the distal forearm using nerve-block anaesthesia. Pain during surgery, flexion of the fingers, bloodless field, and general complications during surgery and 18 months thereafter were recorded. The mean time of ischemia was 19.6±7.5 (10–50) min. A bloodless field was achieved in all cases, and pain during operation was low. Flexion of the fingers were found in most cases but was reducible and not annoying for the surgeon. There were no serious complications during surgery or at follow-up. The tourniquet placed at the distal forearm is painless, safe, and useful in hand surgery.
doi:10.1007/s00264-004-0582-x
PMCID: PMC3456980  PMID: 15480658
22.  Evaluation of Hydrodynamic Limb Vein Injections in Nonhuman Primates 
Human Gene Therapy  2010;21(7):829-842.
The group of Dr. Jon A. Wolff reports results from a study examining the effects of a variety of parameters, such as rate and volume of injection, on the efficiency of hydrodynamic limb vein injection mediated gene transfer of luciferase in rats and nonhuman primates.
Abstract
The administration route is emerging as a critical aspect of nonviral and viral vector delivery to muscle, so as to enable gene therapy for disorders such as muscular dystrophy. Although direct intramuscular routes were used initially, intravascular routes are garnering interest because of their ability to target multiple muscles at once and to increase the efficiency of delivery and expression. For the delivery of naked plasmid DNA, our group has developed a hydrodynamic, limb vein procedure that entails placing a tourniquet over the proximal part of the target limb to block all blood flow and injecting the gene vector rapidly in a large volume so as to enable the gene vector to be extravasated and to access the myofibers. The present study was conducted in part to optimize the procedure in preparation for a human clinical study. Various injection parameters such as the effect of papaverine preinjection, tourniquet inflation pressure and duration, and rate of injection were evaluated in rats and nonhuman primates. In addition, the safety of the procedure was further established by determining the effect of the procedure on the neuromuscular and vascular systems. The results from these studies provide additional evidence that the procedure is well tolerated and they provide a foundation on which to formulate the procedure for a human clinical study.
doi:10.1089/hum.2009.172
PMCID: PMC2938361  PMID: 20163248
23.  Clean up varicose vein surgery--use a tourniquet. 
A controlled randomised trial has been carried out to ascertain if there are tangible benefits from using a tourniquet when avulsing varicose veins during routine varicose vein surgery. Twenty-six patients have been studied. Twenty limbs were operated on with a tourniquet and 20 limbs without a tourniquet. The mean weight of varices excised was 2.76 g (range 0.51-8.79 g) with a tourniquet and 2.68 g (0.77-11.27 g) without a tourniquet (NS, Wilcoxon's rank sum test). Mean blood loss was 16 ml (0-136 ml) with a tourniquet and 107 ml (16-581 ml) without a tourniquet (P less than 0.01, Wilcoxon's rank sum test). The mean time to complete avulsions was 38 min with a tourniquet and 35 min without a tourniquet (NS, Student's t test). The tangible benefits of a tourniquet are limited to the saving of blood which can amount to 500 ml per leg. Losses could amount to 1 litre in bilateral cases operated upon without tourniquet. The method is simple, provides a clean operating field and should be more widely used.
PMCID: PMC2498882  PMID: 2647025
24.  Enhanced External Counterpulsation (EECP) 
Executive Summary
Objective
To assess the effectiveness, and cost effectiveness of EECP in patients with severe anginal symptoms, secondary to chronic coronary disease, who are unresponsive to exhaustive pharmacotherapy and not candidates for surgical/percutaneous revascularization procedures (e.g., angioplasty, coronary bypass surgery).
To assess the effectiveness, and cost effectiveness of EECP in patients with heart failure.
Clinical Need
Angina
Angina is a clinical syndrome characterized by discomfort in the chest, jaw, shoulder, back or arm. Angina usually occurs in patients with coronary artery disease (CAD) involving ≥1 large epicardial artery. However it can also occur in people with valvular heart disease, hypertrophic cardiomyopathy, and uncontrolled hypertension.
Conventional approaches to restoring the balance between oxygen supply and demand focus on the disruption of the underlying disease through: drug therapy (β blockers, calcium channel blockers, nitrates, antiplatelet agents, ACE inhibitors, statins); life-style modifications (smoking cessation, weight loss); or revascularization techniques such as coronary artery bypass graft surgery (CABG) or percutaneous coronary interventions (PCI). (1) Limitations of each of these approaches include: adverse drug effects, procedure-related mortality and morbidity, restenosis after PCI, and time dependent graft attrition after CABG. Furthermore, an increasing number of patients are not appropriate candidates for standard revascularization options, due to co-morbid conditions (HF, peripheral vascular disease), poor distal coronary artery targets, and patient preference. The morbidity and mortality associated with repeat surgical revascularization procedures are significantly higher, and often excludes these patients from consideration for further revascularizations. (2)
Patients with CAD who have chronic ischemic symptoms that are unresponsive to both conventional medical therapy and revascularization techniques have refractory angina pectoris. It has been estimated that greater than 100,000 patients each year in the US may be diagnosed as having this condition. (3) Patients with refractory angina have marked limitation of ordinary physical activity or are unable to perform any ordinary physical activity without discomfort (CCS functional class III/IV). Also, there must be some objective evidence of ischemia as demonstrated by exercise treadmill testing, stress imaging studies or coronary physiologic studies. (1)
Dejongste et al. (4)estimated that the prevalence of chronic refractory angina is about 100,000 patients in the United States. This would correspond to approximately 3,800 (100,000 x 3.8% [Ontario is approximately 3.8% of the population of the United States]) patients in Ontario having chronic refractory angina.
Heart Failure
Heart failure results from any structural or functional cardiac disorder that impairs the ability of the heart to act as a pump.
A recent study (5) revealed 28,702 patients were hospitalized for first-time HF in Ontario between April 1994 and March 1997. Women comprised 51% of the cohort. Eighty-five percent were aged 65 years or older, and 58% were aged 75 years or older.
Patients with chronic HF experience shortness of breath, a limited capacity for exercise, high rates of hospitalization and rehospitalization, and die prematurely. (6) The New York Heart Association (NYHA) has provided a commonly used functional classification for the severity of HF (7):
Class I: No limitation of physical activity. No symptoms with ordinary exertion.
Class II: Slight limitations of physical activity. Ordinary activity causes symptoms.
Class III: Marked limitation of physical activity. Less than ordinary activity causes symptoms. Asymptomatic at rest.
Class IV: Inability to carry out any physical activity without discomfort. Symptoms at rest.
The National Heart, Lung, and Blood Institute (7) estimates that 35% of patients with HF are in functional NYHA class I; 35% are in class II; 25%, class III; and 5%, class IV. Surveys (8) suggest that from 5% to 15% of patients with HF have persistent severe symptoms, and that the remainder of patients with HF is evenly divided between those with mild and moderately severe symptoms.
To date, the diagnosis and management of chronic HF has concentrated on patients with the clinical syndrome of HF accompanied by severe left ventricular systolic dysfunction. Major changes in treatment have resulted from a better understanding of the pathophysiology of HF and the results of large clinical trials. Treatment for chronic HF includes lifestyle management, drugs, cardiac surgery, or implantable pacemakers and defibrillators. Despite pharmacologic advances, which include diuretics, angiotensin-converting enzyme inhibitors, beta-blockers, spironolactone, and digoxin, many patients remain symptomatic on maximally tolerated doses. (6)
The Technology
Patients are typically treated by a trained technician in a medically supervised environment for 1 hour daily for a total of 35 hours over 7 weeks. The procedure involves sequential inflation and deflation of compressible cuffs wrapped around the patient’s calves, lower thighs and upper thighs. In addition to 3 sets of cuffs, the patient has finger plethysmogram and electrocardiogram (ECG) attachments that are connected to a control and display console.
External counterpulsation was used in the United States to treat cardiogenic shock after acute myocardial infarction. (9;10) More recently, an enhanced version namely “enhanced external counterpulsation” (EECP) was introduced as a noninvasive procedure for outpatient treatment of patients with severe, uncontrollable cardiac ischemia. EECP is said to increase coronary perfusion pressure and reduce the myocardial oxygen demand. Currently, EECP is not applicable for all patients with refractory angina pectoris. For example, many patients are considered ineligible for therapy due to co-morbidities, including those with severe pulmonary vascular disease, deep vein thrombosis, phlebitis and irregular heart rhythms, and heart failure. (1)
Very recently, investigation began into EECP as an adjunctive treatment for patients with HF. Anecdotal reports suggested that EECP may benefit patients with coronary disease and left ventricular dysfunction. The safety and effectiveness of EECP in patients with symptomatic heart failure and coronary disease and its role in patients with nonischemic heart failure secondary to LV dysfunction is unclear. Furthermore, the safety and effectiveness of EECP in the different stages of HF and whether it is only for patients who are refractive to pharmacotherapy is unknown.
2003 Health Technology Assessment by the Medical Advisory Secretariat
The Medical Advisory Secretariat health technology assessment (originally published in February 2003) reported on the effectiveness of EECP for patients with angina and HF. The report concluded that there was insufficient evidence to support the use of EECP in patients with refractory stable CCS III/IV angina as well as insufficient evidence to support the use of EECP in patients with HF.
Review Strategy
The aim of this literature review was to assess the effectiveness, safety, and cost effectiveness of EECP for the treatment of refractory stable CCS III/IV angina or HF.
The standard search strategy used by the Medical Advisory Secretariat was used. This included a search of all international health technology assessments as well as a search of the medical literature from December 2002 to March 2006.
A modification of the GRADE approach (11) was used to make judgments about the quality of evidence and strength of recommendations systematically and explicitly. GRADE provides a framework for structured reflection and can help to ensure that appropriate judgments are made. GRADE takes into account a study’s design, quality, consistency, and directness in judging the quality of evidence for each outcome. The balance between benefits and harms, quality of evidence, applicability, and the certainty of the baseline risks are considered in judgments about the strength of recommendations.
Summary of Findings
The Cochrane and INAHTA databases yielded 3 HTAs or systematic reviews on EECP treatment (Blue Cross Blue Shield Technology Evaluation Center [BCBS TEC], ECRI, and the Centers for Medicare and Medicaid Services [CMS]). A search of Medline and Embase December 2005 – March 2006 (after the literature search cutoff from the most recent HTA) was conducted using key words enhanced external counterpulsation, EECP, angina, myocardial ischemia, congestive heart failure. This search produced 1 study which met the inclusion criteria. This level 4a study was inferior in quality to the RCT which formed the basis of the 2003 Medical Advisory Secretariat recommendation.
BCBS reviewed the evidence through November 2005 to determine if EECP improves health outcomes for refractory chronic stable angina pectoris or chronic stable HF. (12) BCBS concluded that the available evidence is not sufficient to permit conclusions of the effect of EECP on health outcomes. Both controlled trials had methodologic flaws (MUST EECP and MUST EECP quality of life studies). The case series and observational studies for both indications while suggestive of a treatment benefit from EECP have shortcomings as well.
On March 20 2006, CMS posted their proposed coverage decision memorandum for external counterpulsation therapy. (13) Overall, CMS stated that the evidence is not adequate to conclude that external counterpulsation therapy is reasonable and necessary for:
Canadian Cardiovascular Society Classification (CCSC) II angina
Heart failure
NYHA class II/III stable HF symptoms with an EF≤35%
NYHA class II/III stable HF symptoms with an EF≤40%
NYHA class IV HF
Acute HF
Cardiogenic shock
Acute MI
In January 2005, ECRI (14) stated that there was insufficient evidence available to draw conclusions about the long-term effectiveness of EECP, with respect to morbidity, survival, or quality of life, for any coronary indication (refractory angina, congestive heart failure, cardiogenic shock and acute MI).
GRADE Quality of the Studies
According to the GRADE Working Group criteria, the quality of the trials was examined (Table 1). (11)
Quality refers to the criteria such as the adequacy of allocation concealment, blinding and followup.
Consistency refers to the similarity of estimates of effect across studies. If there is important unexplained inconsistency in the results, our confidence in the estimate of effect for that outcome decreases. Differences in the direction of effect, the size of the differences in effect and the significance of the differences guide the decision about whether important inconsistency exists.
Directness refers to the extent to which the people interventions and outcome measures are similar to those of interest. For example, there may be uncertainty about the directness of the evidence if the people of interest are older, sicker or have more comorbidity than those in the studies.
As stated by the GRADE Working Group, the following definitions were used in grading the quality of the evidence. (11)
GRADE Quality of Studies
Economic Analysis - Literature Review
No economic analysis of EECP was identified in the published literature.
Estimated Prevalence of Angina in Ontario
3,800 patients with chronic refractory angina:
The number of patients with chronic refractory angina in the US is estimated to be approximately 100,000 (4), this corresponds to about 3,800 patients in Ontario (3.8% × 100,000) with refractory angina.
3,800 patients × $7,000 Cdn (approximate cost for a full course of therapy) ~ $26.6M Cdn.
Estimated Prevalence of Heart Failure in Ontario
23,700 patients EF ≤ 0.35:
This estimate is from an expert (personal communication) at the Institute for Clinical Evaluative Sciences (ICES), where they examined a sample of echocardiography studies drawn from a diagnostic lab in 2001. They found that the prevalence of EF ≤ 0.35 was 8.3%, and if generalized to all patients undergoing echocardiography, there would be 23,700 patients.
23,700 patients with EF ≤35% × $7,000 Cdn ~ $166 M Cdn.
Conclusions
There is insufficient evidence to support the effectiveness and safety of EECP treatment for patients with refractory stable CCS III-IV angina or HF.
As per the GRADE Working Group, overall recommendations consider 4 main factors. (11)
The tradeoffs, taking into account the estimated size of the effect for the main outcome, the confidence limits around those estimates and the relative value placed on the outcome.
The quality of the evidence.
Translation of the evidence into practice in a specific setting, taking into consideration important factors that could be expected to modify the size of the expected effects such as proximity to a hospital or availability of necessary expertise.
Uncertainty about the baseline risk for the population of interest.
The GRADE Working Group also recommends that incremental costs of healthcare alternatives should be considered explicitly alongside the expected health benefits and harms. (11) Recommendations rely on judgments about the value of the incremental health benefits in relation to the incremental costs. The last column in Table 2 is the overall trade-off between benefits and harms and incorporates any risk/uncertainty.
For angina and heart failure, the overall GRADE and strength of the recommendations is “weak” – the quality of the evidence is “low” (uncertainties due to methodological limitations in the study design in terms of study quality and directness), and the corresponding risk/uncertainty is increased due to a budget impact of approximately $26.6 M Cdn or $166 M Cdn respectively while the cost-effectiveness of EECP is unknown and difficult to estimate considering that there are no high quality studies of effectiveness.
Overall GRADE and Strength of Recommendation (Including Uncertainty)
PMCID: PMC3379533  PMID: 23074496
25.  Hydro-Jet Assisted Laparoscopic Cholecystectomy: Initial Experience in a Porcine Model 
Background and Objectives:
Hydro-Jet technology has long been used for cutting various materials like metal and wood in the industrial field. In the medical field, this technology has been applied successfully for selective cutting of the parenchyma of the liver. However, to our knowledge, no data exist on the use of the Hydro-Jet technique for laparoscopic cholecystectomy. The purpose of this study was to evaluate a new dissection technique using a high-pressure water stream (Hydro-Jet) and a new dissection probe for laparoscopic cholecystectomy.
Methods:
Thirty pigs underwent laparoscopic cholecystectomy. Pigs were randomized to receive either the conventional or Hydro-Jet assisted dissection technique. The feasibility of this technique and the features of surgical dissection were evaluated and compared between the 2 groups.
Results:
Laparoscopic cholecystectomy was successful in all animals with no need for conversion to open surgery. The mean operative time was 28 and 36 minutes for Hydro-Jet versus conventional dissection, respectively. Complications using the Hydro-Jet and conventional techniques included 6% and 20% gallbladder perforation and 6.5% and 13% liver laceration, respectively. The use of the Hydro-Jet for cholecystectomy had clear technical advantages over conventional dissection. The Hydro-Jet resulted in a selective dissection of fibrous and connective tissue preserving blood vessels for later ligation. Therefore, the dissection was performed in a relatively bloodless field. The ease of dissection using the new bent tipped dissector represents another advantage. Finally, the continuous water flow allowed a clear view for the operator.
Conclusions:
This study shows that Hydro-jet dissection represents an excellent alternative to the conventional technique for laparoscopic cholecystectomy. The improved anatomical dissection combined with an almost bloodless operating field secondary to continuous water flow may decrease dissection-related complications.
PMCID: PMC3043399  PMID: 12002298
Laparoscopy; Cholecystectomy; Hydro-Jet; Dissection; Animal

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