The digital tourniquet: How safe is it?

To measure the pressure generated beneath a digital tourniquet, this study was based on the mathematical relationship between pressure and resistance in latex rubber. The digital tourniquets were either a 1/4-inch Penrose drain or a rolled glove finger. Pressures generated beneath the rolled glove finger were noted to range between 200 and 1200 mm Hg. Pressure beneath the Penrose drain ranged between 100 and 650 mm Hg in one study group and between 120 and 500 mm Hg in a second study group consisting of fingertip injuries. A method was developed based on the same mathematical relationship to control pressure. Marks spaced 26 mm apart on a Penrose drain are wrapped around a finger until the marks touch and the Penrose drain is clamped. With this technique, the pressure beneath the Penrose drain will remain between 250 and 375 mm Hg. Less strain will be required for smaller fingers and more strain will be required for larger fingers; however, the pressure will remain within a predictable range.     

Digital tourniquet: a new technique

Digital tourniquets are frequently used during operations in the hand and foot. The commonest tourniquets used are the Penrose drain, the Jacques bladder catheter and a rolled up finger from a surgical glove. Generally, these are relatively safe and efficacious. However, complications related to them have been reported. Application and alteration of a Penrose type drain can be difficult during a procedure. A glove tourniquet once applied cannot be altered. We present here a unique way of using a Jacques catheter as a flexible digital tourniquet. We have found it very effective, user-friendly and extremely easy to apply and alter before and during surgery.     

Guidelines for the use of digital tourniquets based on physiological pressure measurements

A potential complication of a digital tourniquet is neurovascular damage due to excessive tissue pressure. A technique for measuring digital tourniquet pressures was developed in our laboratory and was tested on fresh cadaver hands in order to establish guidelines for proper application of tourniquets. A saphenous vein from a fresh cadaver was laid subcutaneously along the neurovascular bundle of the test finger. Digital tourniquets consisting of Penrose drains or rolled surgical gloves were then applied in a standardized fashion. Saline solution was injected through the saphenous vein in a quasi-static fashion using a Harvard pump, and the pressure within the vein was monitored with a pressure transducer. When the pressure within the vein reached the closing pressure generated by the tourniquet, the pressure stabilized due to leakage of fluid beyond the tourniquet. Digital tourniquets applied in customary fashion by selected physicians and surgeons produced a wide range of closing pressures that did not exceed 360 millimeters of mercury. Rolled surgical gloves produced closing pressures ranging from 113 to 363 millimeters of mercury, depending on the relationship between the size of the glove and that of the hand. Penrose drains produced closing pressures of more than 800 millimeters of mercury, depending on the amount of stretch applied.     

A Novel Digital Tourniquet Using a Sterile Glove and Hemostat

Background. Surgery of the digit is facilitated with adequate hemostasis for visualization of the operative field. Several types of tourniquets have been used for this purpose, including glove fingers, Penrose drains, Marmed digital tourniquets, and standard pneumatic tourniquets.
Objective. To present a novel method to achieve hemostasis during surgery of the digit.
Materials. A slightly oversized sterile glove, a hemostat, and a pair of scissors.
Conclusion. We present a novel method to achieve hemostasis using a sterile glove and a hemostat, that allows the surgeon to methodically titrate the amount of compression necessary to attain a bloodless field while minimizing the risks of excessive pressures.
Surgery of the digit is facilitated with adequate hemostasis for visualization of the operative field. Several types of tourniquets have been used for this purpose, including glove fingers, Penrose drains, Marmed digital tourniquets, and standard pneumatic tourniquets. We present a novel method to achieve hemostasis using a sterile glove and a hemostat that allows the surgeon to methodically titrate the amount of compression necessary to attain a bloodless field while minimizing the risks of excessive pressures.     

Digital tourniquets: a comparative analysis of pressures and pain perception

Digital tourniquets have been condemned because of the reported occurrence of neurovascular complications. This study compares the pressures and pain perception between three different tourniquets, namely the rubber glove finger stall, Foley's urinary catheter and the commercial band tourniquet. The subjects involved were 20 volunteers with 80 fingers studied in total. A direct pressure measuring technique was used. The pressures recorded were highest and most variable with the catheter tourniquet, whereas the rubber glove tourniquet recorded the lowest pressures. Correspondingly, visual analogue scale in relation to patient discomfort showed high scores with the catheter tourniquet and low scores with the rubber glove tourniquet. We conclude that catheter tourniquet use should be avoided as it generates extreme and variable pressures, whereas rubber glove finger stall tourniquets appear as a better alternative.     

The right turn around: Penrose tourniquet application in paediatrics

IntroductionCommercially available tourniquets are ill-suited for paediatric patients with limb circumferences smaller than the required mechanism, forcing surgeons to improvise. This study aimed to quantify pressures exerted by the Penrose tourniquet when applied on a phantom model and evaluate the intra-/inter-rater reproducibility of the technique previously proposed.MethodsEight calibrated pressure sensors were distributed evenly along the inner and outer circumference of a silicon-based model. A 30cm-by-3.2 cm ARGYLE Penrose drain, 4-by-4 gauze, marker and ruler were used. The optimal interval for arterial occlusion was determined to be 70% of limb circumference. The tourniquet was secured using two half-knots formed by gauze.ResultsTwo-turns of the tourniquet about the model generated mean pressures (SD) of 209.43 (SD:35.98 mmHg) (95%CI: 195.85–224.00 mmHg) (outer-sensor) and 246.32 (SD:61.92 mmHg) (95%CI: 221.02–273.49 mmHg) (inner-sensor). Three-turns generated mean pressures of 302.07 (SD:23.98 mmHg) (95%CI: 292.29–312.53 mmHg) (outer-sensor) and 314.44 (SD:56.70 mmHg) (95%CI: 291.25–338.25 mmHg) (inner-sensor).ConclusionThe Penrose tourniquet has clinical utility, particularly for patients where commercially available tourniquets are not suitable. Current application techniques generate inconsistent pressures. Using the existing model, further refinement can be done to improve the consistency and safety of the application. We recommend using intervals of slightly more than 70% of limb circumference and only two turns of the Penrose tourniquet during application.Level of EvidenceV     

Pathophysiology of rupture of the pulmonary artery by pulmonary artery balloon-tipped catheters

High pressures have been reported in pulmonary artery catheter balloons. This study was undertaken to determine the in vitro rupturing pressures of human peripheral pulmonary arteries and to evaluate whether such pressures could be generated under clinical conditions. The in vitro model then was confirmed in vivo in the dog and the evolution of a rupture of a peripheral pulmonary artery studied. In vitro, pulmonary arteries of subjects under age 60 yr are remarkably resistant and tolerate intra-balloon pressures of 2700 mm Hg in the one mid-pulmonary artery studied and up to 4219 +/- 720 mm Hg (mean +/- SD) in the distal pulmonary artery. Subjects over the age of 60 yr have significantly lower rupturing pressures (1965 +/- 540 mm Hg in the mid-pulmonary artery, and 2498 +/- 600 mm Hg in the distal pulmonary artery), (P less than 0.05). Thus overdistension by the balloon may explain most ruptures. Preexisting pulmonary hypertension did not affect in vitro rupturing pressures. Clinicians generated intraballoon mean pressures of 795 +/- 130 mm Hg, with 20% of them generating higher and potentially dangerous pressures (1000 mm Hg or more). The in vitro model was confirmed by in vivo studies in dogs with pressures that cause pulmonary artery rupture. Furthermore, in normal dogs, rupture of a peripheral pulmonary artery was without complications. This suggests that rupture of the peripheral pulmonary artery may occur clinically more frequently than reported. The user of flotation pulmonary arterial catheters should be aware of the dangers associated with this diagnostic tool. In particular, liquids must never be used to inflate pulmonary arterial catheter balloons.     

The wrist tourniquet: an alternative technique in hand surgery

This study investigated the efficacy and safety of the use of a size 8 1/2 surgical glove as a wrist tourniquet in hand surgery. A neonatal blood pressure cuff was placed under the wrist tourniquet to measure the presssures generated with use of this technique. The wrist tourniquet was applied in 25 consecutive procedures. Pressures generated with this technique ranged from 110 mm Hg to 260 mm Hg, with a mean pressure of 158 mm Hg. The average tourniquet time was 29 minutes, with the longest time being 135 minutes. The tourniquet achieved a bloodless surgical field in 24 (96%) of the 25 patients, and was well tolerated in all but two patients. Aside from tourniquet pain in these two (8%) patients, and tourniquet failure in one (4%) patient, there were no other complications associated with the wrist tourniquet. The size 8 1/2 surgical glove can be adopted as an effective and safe tourniquet in hand surgery.     

Foreign bodies in urinary bladder

Ten patients with foreign bodies in the bladder are herein reported from the urologic admissions of the Squier Clinic at Columbia Presbyterian Medical Center. Twelve foreign bodies were removed from these 10 patients. They consisted of three glass stirring rods, two hairpins, two umbilical tapes, one ball-point pen, one pencil, one rubber tube, one Penrose drain, and one bougie. Seven of these objects were self-introduced; the Penrose drain was left in the bladder during a previous suprapubic prostatectomy, and the two umbilical tapes used in previous gynecologic surgery had worked their way into the bladder. The clinical features, diagnostic maneuvers, and methods of treatment have been described, and the literature on foreign bodies reviewed.     

The AB Portable Driver Generates Higher Drive‐Line Pressures Possibly Leading to Accelerated Hemolysis

The AB5000 Circulatory Support System is paracorporeal pulsatile ventricular assist device. The AB Portable Driver is a portable console for this system. We experienced two cases with accelerated hemolysis while receiving support by the AB Portable Driver. The purpose of this study was to clarify the mechanical differences associated with the hemolysis between the AB5000 console and the AB Portable Driver. The mock circulatory system modeled by an AB5000 ventricle and a blood sampling bag of vinyl chloride was run with an AB5000 console or AB Portable Driver. The peak drive‐line pressure, the mean arterial cannula pressure and the pumping rate of the VAD were recorded. The AB5000 console generated a peak drive‐line pressure of 280–300 mm Hg in LVAD mode and 210–220 mm Hg in RVAD mode, approximately 100 mm Hg lower than officially documented. In contrast, the AB Portable Driver generated pressures of 310–330 mm Hg in LVAD mode and 230–250 mm Hg in RVAD mode, 65–95 mm Hg higher than officially documented. The AB Portable Driver console generates higher drive‐line pressures than the AB5000 console, possibly explaining the accelerated hemolysis.     

The distal blood pressure predicts healing of amputations on the feet

The healing of digital and transmetatarsal forefoot amputations was compared with the systolic digital and ankle blood pressure, both measured with a strain-gauge, and with the skin perfusion pressure on the forefoot measured with the isotope washout technique. In 85 out of 134 legs (63 per cent) the amputation healed. The frequency of healing correlated statistically significantly with all three measures of distal blood pressures, the closest correlation being with the systolic digital blood pressure (SDBP). As measured in 110 cases the healing rates were: SDBP less than 20 mm Hg: four out of 23; SDBP 20-29 mm Hg: 13 out of 22; SDBP greater than or equal to 30 mm Hg: 51 out of 65. Ankle pressures and skin perfusion pressures were less useful. Invasive infection was present in 40 out of 102 diabetic legs and, next to ischaemia, was the major determinant of the healing results.     

Assessment of arterial obstruction in vessels supplying the fingers by measurement of local blood pressures and the skin temperature response test--correlation with angiographic evidence.

The systolic blood pressure measured in the fingers and wrists by the spectroscopic method and in the arm by auscultation were correlated with angiographic evidence of organic arterial obstruction in 29 patients. The pressures also were measured in 14 normal people. Results in the normal people suggest that a difference of more than 15 mm. Hg between the pressure measured simultaneously in corresponding fingers (or any two or more fingers), an absolute digital pressure less than 70 mm. Hg, or wrist-to-digit gradient of more than 30 mm. Hg, all in the warm subject and warmed hand, indicated the presence of organic obstruction. These criteria indicated the presence of organic arterial obstructive disease in 25 of 26 hands with definite angiographic evidence of it. The pressures were "normal" in five hands with no angiographic evidence of organic arterial obstruction. The digital skin temperature response to indirect heating was much less successful than were pressure measurements in identifying fingers with organic arterial obstructive disease.     

Effect of an upper-arm constricting device on arm blood pressure measurements

Thousands of blood pressure measurements are done daily without the patients' disrobing. This study was therefore undertaken to determine the validity of such measurements, especially those taken when the patient's armsleeve has been rolled up onto the proximal aspect of the arm. An inflatable constricting device was applied to the proximal aspect of the arm and a standard sphygmomanometer was applied distal to the inflatable cuff. The constricting cuff was inflated to 0, 20, 40, 60, 80, and 100 mm Hg in random sequence, and the blood pressure was recorded at each level. Statistically significant elevations in the mean systolic blood pressure were detected at proximal constricting pressures of 80 mm Hg (P less than .01) and 100 mm Hg (P less than .001), and in the mean diastolic blood pressure at 20 mm Hg (P less than .005). However, the magnitude of the elevations was small: 3.9, 4.4, and 2.5 mm Hg, respectively. We conclude that though a proximal constricting device may induce statistically significant alterations in blood pressure measurements these alterations are small and not likely to affect treatment decisions.     

Skin protection against methylmethacrylate

Ordinary surgical rubber gloves are penetrated by methylmethacrylate monomer (MMA) in less than 1 minute, as demonstrated by gas chromatographic measurements. A three-layered PVP glove, 0.07 mm thick--consisting of an outer layer of polyethylene, an intermediary layer of ethylene vinyl alcohol copolymer, and an inner layer of polyethylene--was impervious for 20 minutes, whereas a viton-butyl rubber glove, 0.27 mm thick, was impervious for 15 minutes. The PVP glove is recommended to orthopedic surgeons, nurses, and other handling acrylic bone cements to avoid sensitization, and is especially recommended to persons with known contact allergy to MMA.     

Drainage or suture of the cavity after breast biopsy.

An initial series of 105 women who underwent excision biopsy of the breast were entered into a controlled randomised trial to determine the effect on postoperative morbidity of drainage of the cavity with a soft rubber Penrose drain. The use of this drain had no effect on the incidence of postoperative wound complications (drain 11 of 40 (28%), no drain 10 of 58 (17%]. A second series of 202 women were entered into a randomised controlled trial to determine the effect of closed suction drainage and suture of the cavity after breast biopsy. The use of this drain significantly reduced the incidence of postoperative wound complications (drain 9 of 93 (10%), no drain 22 of 105 (21%], but although suture of the cavity halved the number of wound complications (suture 11 of 97 (11%), no suture 20 of 101 (20%], this did not reach statistical significance. Wound complications were more frequent with large wounds (28%) than with smaller ones (15%), and with less experienced operators (registrar 21%, senior registrar/consultant 10%). We conclude that a closed suction drain will reduce the incidence of wound haematomas after breast biopsy but that a Penrose drain is ineffective in the prevention of wound complications.     

Skin protection against methylmethacrylate

Ordinary surgical rubber gloves are penetrated by methylmethacrylate monomer (MMA) in less than 1 minute, as demonstrated by gas chromatographic measurements. A three-layered PVP glove, 0.07 mm thick - consisting of an outer layer of polyethylene, an intermediary layer of ethylene vinyl alcohol copolymer, and an inner layer of polyethylene - was impervious for 20 minutes, whereas a viton-butyl rubber glove, 0.27 mm thick, was impervious for 15 minutes.

The PVP glove is recommended to orthopedic surgeons, nurses, and other handling acrylic bone cements to avoid sensitization, and is especially recommended to persons with known contact allergy to MMA.     

A Comparison of Flow Gradients across Disposable Arterial Perfusion Cannulas

Five-hundred members of The Society of Thoracic Surgeons were canvassed to discover which cannulas are currently used for open-heart surgical procedures in adults; 120 surgeons responded. The mean arterial line pressure produced by 29 disposable arterial perfusion cannulas (size range, 16F to 30F) at flow rates of 1 to 5 liters per minute was compared. A roller pump with perfusion tubing 95 mm (0.75 inch) in diameter was used with water as the test solution. Line pressures in these cannulas ranged from 22.4 ± 2.30 (standard deviation) to 271.0 ± 6.60 mm Hg at 5 L/min. Four 24F cannulas had gradients of less than 55 mm Hg at a flow rate of 5 L/min, and 6 cannulas—4 of which were 22F and 2, 24F—had gradients higher than 150 mm Hg at 5 L/min. A number of cannulas kinked easily, and these showed marked increases in line pressure.The following results were obtained from this study: (1) a wide range of line pressures was observed in disposable arterial perfusion cannulas currently in clinical use; (2) some cannulas currently used for cardiopulmonary bypass in adults generated excessive line pressure; and (3) both material and design affect function, with some designs being safer than others. Cardiac surgeons should base the choice of an arterial perfusion cannula on the best performance and safest design available to avoid cannula-related problems at operation.     

Controlled hypotension and minimal inflation pressure: a new approach for pneumatic tourniquet application in upper limb surgery

Minimal inflation pressures are recommended for limb surgery to eliminate complications attributable to high inflation pressures with the pneumatic tourniquets. We applied controlled hypotension and a minimal inflation pressure (CHAMIP) technique to provide a bloodless surgical field. Thirty-six patients scheduled for upper extremity surgery were randomized equally to receive either normotensive anesthesia and conventional inflation pressures or controlled hypotension (systolic arterial blood pressure of 80-100 mm Hg and mean arterial blood pressure >60 mm Hg) and minimum inflation pressures. Anesthesia was induced with propofol IV bolus and remifentanil IV continuous infusion and maintained with propofol and remifentanil IV continuous infusion. To determine the minimal inflation pressure, the digital plethysmograph was applied to the second finger at the side of the operation and the tourniquet was inflated slowly until the arterial pulsations disappeared on the oscilloscope. A bloodless surgical field was obtained in almost all patients, even though systolic arterial blood pressures (100-138 mm Hg versus 80-100 mm Hg) and applied tourniquet inflation pressures (270 mm Hg versus 110-140 mm Hg) were significantly lower in the hypotensive group. No complications associated with controlled hypotension were encountered. In conclusion, CHAMIP may be a safe and reliable method for upper extremity surgery performed with pneumatic tourniquets. IMPLICATIONS: Pneumatic tourniquets are associated with adverse effects resulting from high inflation pressures. Therefore, minimal inflation pressures are recommended in extremity surgery. To reach real minimal inflation pressure the patient's blood pressure must be reduced. We used controlled hypotension with remifentanil and propofol to reach minimal inflation pressures.     

In vitro comparison of the effects of rough and polished stem surface finish on pressure generation in cemented hip arthroplasty

Background and purpose High pressures around implants can cause bone lysis and loosening. We investigated how pressures are generated around cemented femoral stems.Method We compared the pressures generated by rough and polished tapered stems at their cement interfaces, in an in vitro model, before and after 1 million load cycles.Results At the start of the study, the loading of both polished and rough stems generated interface pressures that were not statistically significantly different. After 1 million load cycles, the rough stems generated greater interface pressures than at the start (p = 0.03), with maximum pressure wave amplitudes of 450,000 Pa or 3,375 mm Hg. The pressures generated by polished stems were similar before and after 1 million load cycles, and were lower than the pressures generated by the rough stems (p = 0.01). Stem loading caused micromotion between the stem and cement. Polished stems migrated distally in the cement but retained rotational and axial stability. The rough stems also migrated distally and wore the cement mantle, leading to increased rotational instability.Interpretation The change in the rotational micromotion of the rough stem is likely to be the principal cause of the increased stem pump output and to be a key factor in the longevity of cemented femoral implants.     

Inelastic compression legging produces gradient compression and significantly higher skin surface pressures compared with an elastic compression stocking

The purposes of this study were to (1) investigate compression levels beneath an inelastic legging equipped with a new pressure-adjustment system, (2) compare the inelastic compression levels with those provided by a well-known elastic stocking, and (3) evaluate each support's gradient compression production. Eighteen subjects without venous reflux and 12 patients with previously documented venous reflux received elastic and inelastic compression supports sized for the individual. Skin surface pressures under the elastic (Sigvaris 500, 30-40 mm Hg range, Sigvaris, Inc., Peachtree City, GA) and inelastic (CircAid C3 with Built-in-Pressure System [BPS], CircAid Medical Products, San Diego, CA) supports were measured using a calibrated Tekscan I-Scan device (Tekscan, Inc., Boston, MA). The elastic stocking produced significantly lower skin surface pressures than the inelastic legging. Mean pressures (+/- standard error) beneath the elastic stocking were 26 +/- 2 and 23 +/- 1 mm Hg at the ankle and below-knee regions, respectively. Mean pressures (+/- standard error) beneath the inelastic legging with the BPS were 50 +/- 3 and 38 +/- 2 mm Hg at the ankle and below-knee regions, respectively. Importantly, our study indicates that only the inelastic legging with the BPS produces significant ankle to knee gradient compression (p = .001).