Noninvasive Blood Pressure Cuff Research Articles

Butorphanol-Azaperone-Medetomidine Is as Safe and Effective as Nalbuphine-Azaperone-Medetomidine for Immobilization of Juvenile American Black Bears (Ursus americanus).

Immobilization kits including butorphanol-azaperone-medetomidine (BAM) and nalbuphine-azaperone-medetomidine can provide effective, safe, and easy-to-use protocols in bears. Nalbuphine-azaperone-medetomidine is not commercially available but may be useful for wildlife agencies because it does not contain controlled substances. This study directly compared BAM to nalbuphine-azaperone-medetomidine immobilization in 10 juvenile healthy black bears (10 mo old; four females, six males) undergoing prerelease examinations after rehabilitation. Bears were immobilized via remote delivery of 1 mL of BAM (n=5) or nalbuphine-azaperone-medetomidine (n=5) intramuscularly in the shoulder during December (randomized, blinded trial). Bears were intubated, monitored with an electrocardiogram, pulse oximeter, capnograph, noninvasive blood pressure cuff, and rectal thermometer, and underwent physical examination, sample collection, morphometrics, and ear-tag placement. Induction, physiologic, and recovery parameters were recorded, including arterial blood gas analysis. The anesthetic agents were antagonized with atipamezole and naltrexone. There were no differences between protocols in induction or recovery times. There were no differences between protocols in heart rate, respiratory rate, temperature, oxygen saturation, end-tidal CO2, mean arterial pressure, or blood gas analysis or any differences between male and female bears in any parameters. Bears were hypertensive and normoxemic with low oxygen saturation via pulse oximeter, but all recovered smoothly and were released within 2 h of recovery. This study supports that nalbuphine-azaperone-medetomidine is clini-cally as safe and effective as BAM in American black bears.

Left ventricular myocardial work in patients with high gradient severe symptomatic aortic stenosis

Abstract Background Left ventricular myocardial work (LVMW) is a novel method to evaluated left ventricular (LV) function using pressure-strain loops. It might correct global longitudinal strain (GLS) for afterload, being eventually useful to assess whether GLS reduction is due to reduced contractility (reflected as reduced myocardial work) or increased afterload (reflected as increased myocardial work). Aim To describe indices of LVMW in a group of patients with severe symptomatic aortic stenosis (AS). Methods We prospectively studied 104 consecutive patients (age: 71 years [IQR 66.5–75.5] years, 51% men) with severe symptomatic high gradient AS: mean transaortic pressure gradient: 56.5mmHg [IQR 46.8–67.8]; aortic valve area: 0.73cm2 [IQR 0.61–0.88]; indexed stroke volume: 47.7±1.3 mL/m2 (11 patients with low-flow AS), preserved LV ejection fraction (EV) (LVEF: 56.0% [51.0–61.3]; GLS: −14.5% [IQR −16.1 to −10.6]), with no previous coronary artery disease and no history of cardiomyopathy. Beyond complete transthoracic echocardiography, all patients underwent cardiac magnetic resonance for LV myocardium tissue characterization. As proposed for AS, LV systolic pressure was corrected adding the mean transaortic pressure gradient to non-invasive systolic blood pressure cuff measurement in the echocardiographic algorithm. Four LVMW indices were collected in 83 patients (patients excluded for atrial fibrillation, left bundle branch block or absence of non-invasive blood pressure registration) and correlated to LV function indexes, LV hypertrophy and remodeling, myocardial tissue characterization, BNP and troponin levels (Pearson or Spearman correlation). These same indexes were compared in patients with LV ejection fraction (EF) below and above 50%, normal and reduced flow and presence of replacement fibrosis. Results Global constructive work (GCW) (2658.6±76.4mmHg%), global myocardial work (GMW) (2218.7±74.9mmHg%) and global wasted work (GWE) (262.0mmHg% [198.8–339.5]) were high above normal with concomitant lower work efficiency (WE) (88.0% [83.2–91.8]. Weak correlations were found between LVMW indexes and parameters describing aortic valve severity, flow and LV function (table). Except for significant differences of LVMI in patients with reduced LV ejection fraction (GCW 2770.3±687.4 vs 2056.0±380.7mmHg%, p=0,014 and GMW 2362.5±657.9 vs 1621.3±319.9, p=0,021 in patients with LV EF>50% vs. LV EF<50%, respectively) work indexes were neither significantly different in low-flow patients nor in those with myocardial late gadolinium enhancement. Conclusions Global constructive and myocardial work are increased in these patients with severe aortic stenosis. This might reflect an increased afterload predominance rather than a LV functional impairment, particularly relevant in this group of patients with exclusive high gradient disease and preserved LVEF. Funding Acknowledgement Type of funding sources: None. Correlations between LVMI – LV function

Improving Accurate Blood Pressure Cuff Allocation in Patients with Obesity: A Quality Improvement Initiative.

Accurate noninvasive blood pressure (NIBP) measurement requires use of an appropriately sized cuff. We aimed to improve the perioperative allocation of NIBP cuffs in patients with Class II–III obesity. In the baseline evaluation, we measured the mid-arm circumference (MAC) of 40 patients with BMI > 35 kg/m2, documenting the corresponding cuff allocated by pre-operative nurses. The intervention consisted of the introduction of cuff allocation based on MAC measurement and augmented NIBP cuff supplies. We completed a re-evaluation and evaluation of the intervention by staff survey, using 5-point Likert scales and free text comments. At baseline, the correct cuff was allocated in 9 of 40 patients (22.5%). During the intervention, education occurred in 54 (69.2%) peri-operative nursing staff. Upon re-evaluation, the correct cuff was allocated in 30 of 40 patients (75.0%), a statistically significant improvement (χ2 = 22.1, p < 0.001). Ninety-three of 120 staff surveys were returned (78%). Eleven out of 18 preoperative staff surveyed (61.1%) felt confident measuring the arm and selecting the correct cuff. Six (33%) agreed that taking the arm measurement added a lot of extra work. Equipment shortages, accuracy concerns, and clinical workarounds were reported by staff. Our intervention increased the proportion of correct cuffs allocated, but equipment and practical issues persist with NIBP cuff selection in obese patients.

Perioperative Considerations in Osteogenesis Imperfecta: A 20-Year Experience with the Use of Blood Pressure Cuffs, Arterial Lines, and Tourniquets.

Osteogenesis imperfecta (OI) is a rare genetic connective-tissue disorder with bone fragility. To avoid iatrogenic fractures, healthcare providers have traditionally avoided using non-invasive blood pressure (NIBP) cuffs and extremity tourniquets in the OI population in the perioperative setting. Here, we hypothesize that these procedures do not lead to iatrogenic fractures or other complications in patients with OI. A retrospective study of all children with OI who underwent surgery at a single tertiary care children’s hospital from 1998 to 2018 was performed. Patient positioning and the use of NIBP cuffs, arterial lines, and extremity tourniquets were documented. Fractures and other complications were recorded. Forty-nine patients with a median age of 7.9 years (range: 0.2–17.7) were identified. These patients underwent 273 procedures, of which 229 were orthopaedic operations. A total of 246 (90.1%) procedures included the use of an NIBP cuff, 61 (22.3%) an extremity tourniquet, and 40 (14.7%) an arterial line. Pediatric patients with OI did not experience any iatrogenic fractures related to hemodynamic monitoring or extremity tourniquet use during the 20-year period of this study. Given the benefits of continuous intra-operative hemodynamic monitoring and extremity tourniquets, we recommend that NIBP cuffs, arterial lines, and tourniquets be selectively considered for use in children with OI.

Myocardial work assessment in severe aortic stenosis undergoing transcatheter aortic valve replacement.

Myocardial work is a novel echocardiographic algorithm that corrects speckle-tracking-derived global longitudinal strain (GLS) for afterload using non-invasive systolic blood pressure as a surrogate for left ventricular systolic pressure (LVSP). Yet, in patients with severe aortic stenosis, non-invasive systolic blood pressure does not equal LVSP. We evaluated 35 patients with severe aortic stenosis who underwent transcatheter aortic valve replacement (TAVR). Transthoracic echocardiography, including myocardial mechanics, was performed pre- and post-TAVR. We performed simultaneous echocardiographic and cardiac catheterization measurements in 23 of the 35 patients at the time of TAVR. Peak and mean aortic gradients were calculated from echocardiographic and cardiac catheterization data. Peak-to-peak LV-aortic gradient correlated highly with mean LV-aortic gradient (r = 0.96); measured LVSP correlated highly with our novel method of non-invasively estimated LVSP (non-invasive systolic blood pressure cuff + Doppler-derived mean aortic gradient, r = 0.92). GLS improved from pre- to post-TAVR (-14.2% ± 4.3 vs. -15.1% ± 3.2), and myocardial work reduced from corrected pre-TAVR to post-TAVR (global work index: 1856.2 mmHg% ± 704.6 vs. 1534.8 ± 385.0). We propose that non-invasive assessment of myocardial work can be reliably performed in aortic stenosis by the addition of mean aortic gradient to non-invasive systolic blood pressure. From this analysis, we note the novel and unique finding that GLS can improve as myocardial work reduces post-TAVR in patients with severe aortic stenosis. Both GLS and myocardial work post-TAVR remain below normal values, requiring further studies.

Contact Dermatitis with a Nylon Non-Invasive Blood Pressure Cuff after Elective Surgery.

Contact Dermatitis with a Nylon Non-Invasive Blood Pressure Cuff after Elective Surgery.

The Reliability of Noninvasive Blood Pressure Measurement Through Layers of Autumn/Winter Clothing: A Prospective Study

In recent years a number of publications have appeared describing noninvasive blood pressure (NIBP) measurement with 1 layer of light cloth between the patient's skin and the NIBP cuff. In this study we investigated the reliability of NIBP measurements performed through 2 and 3 layers of autumn/winter clothing in 2 research groups: healthy volunteers and patients. Oscillometric NIBP measurements were made in a random order: 1) on the exposed arm; 2) on the arm covered by a standardized cotton and polar fabric test sleeve; and 3) with the arm covered by a cotton-polar fabric and down jacket test sleeve. The time taken for measurement was also recorded. We performed measurement in 101 volunteers and 50 patients and found no clinically or statistically significant differences in NIBP. Mean±SD values in the volunteer group were 1) 130/80±14/8 mm Hg; 2) 130/81±15/8 mm Hg; and 3) 128/81±14/8 mm Hg. In the patient group the values were 1) 140/82±34/15 mm Hg; 2) 140/84±33/15 mm Hg; and 3) 137/84±32/15 mm Hg. Measuring over a sleeved arm extended the time of measurement by an average of 3.5 s in comparison with bare arm measurement. Our findings confirm that it is possible to perform reliable NIBP measurements over 2 and 3 layers of autumn/winter clothing. Measuring NIBP with a clothed arm does not show clinical or statistically significant differences in comparison with measurements performed on the bare arm.

Abstract WP3: Decreases in Blood Pressure During Endovascular Stroke Therapy are Associated With Larger Infarct Volumes and Poor Functional Outcome

Background: After large-vessel occlusion (LVO), the fate of the ischemic penumbra, and ultimately final infarct volume, largely depends on compensatory collateral perfusion. Blood pressure (BP) management is critical for avoiding cerebral hypoperfusion and further secondary neurological injury. In this study, we examined the effect of BP reductions and sustained relative hypotension during endovascular therapy (EVT) on infarct volume and functional outcome. Methods: We retrospectively studied patients with LVO stroke who underwent mechanical thrombectomy. Intra-procedural MAP was monitored using a non-invasive BP cuff or an intra-arterial catheter. ΔMAP was calculated as the difference between admission MAP and lowest MAP during EVT. Sustained hypotension (aMAP) was measured as the area between admission MAP and continuous measurements of intra-procedural MAP until recanalization was achieved or procedure was completed. Final infarct volume was measured on MRI at 24hrs. Functional outcome was assessed using the modified Rankin Scale (mRS) at discharge and 90 days. Associations with outcome were analyzed using linear and ordinal regressions and adjusted for age, gender, admission NIHSS and TICI score. Results: 262 patients (mean age 71±16, 58% F, mean NIHSS 17) were included in the analysis. Mean admission MAP was 106 mmHg. 86% of patients experienced ΔMAP reductions during EVT (mean 25±24 mmHg). ΔMAP was associated with larger final infarct volume (n=189, p=0.042). Median ΔMAP among patients with favorable outcomes (mRS 0-3) was 19 mmHg (IQR 3-39) compared to 33 mmHg (IQR 8-49) among patients with poor outcome (p=0.024). ΔMAP was independently associated with higher (worse) mRS scores at discharge (n=255, OR 1.013, 95% CI 1.004-1.023, p=0.008) and at 90 days (n=156, OR 1.014, 95% CI 1.001-1.023 p=0.034). The association between aMAP and outcome was highly significant at discharge (p=0.003) and 90 days (p=0.018). Conclusions: BP reduction prior to recanalization may lead to larger infarct volumes and worse functional outcomes for patients affected by LVO stroke. These results underline the importance of BP management during EVT, and highlight the need for further investigation of active BP management strategies to optimize clinical outcomes.

Incidence of Fractures From Perioperative Blood Pressure Cuff Use, Tourniquet Use, and Patient Positioning in Osteogenesis Imperfecta.

Osteogenesis imperfecta (OI) is a rare connective tissue disease with varying severity. Patients with OI are highly susceptible to skeletal fractures. Optimal perioperative management of these patients is not well defined. We investigated the risks associated with intraoperative use of noninvasive blood pressure (NIBP) cuffs, tourniquets, and intra-arterial catheters, and patient positioning in children with OI. We retrospectively reviewed records of patients younger than 21 years with OI who underwent surgery with general anesthesia from 2010 to 2016 at our tertiary care center. The primary outcome of interest was iatrogenic fracture caused by NIBP cuff use, tourniquet use, or patient positioning. The secondary outcome of interest was complications associated with intra-arterial catheter use. Thirty-seven patients (15 girls) with a mean age of 10±4.8 years underwent 96 orthopaedic procedures (lower extremity, upper extremity, and spine) and 2 nonorthopaedic procedures (myringotomy, dental rehabilitation). Blood pressure was monitored with NIBP cuffs in 81 surgeries and intra-arterial catheters in 17 surgeries. Tourniquets (all applied to the lower extremity at a pneumatic pressure of 250 mm Hg) were used to minimize bleeding in 30 surgeries. There were no iatrogenic fractures associated with NIBP cuff use. One patient had a left humerus fracture that occurred during preoperative patient positioning. There were no fractures associated with tourniquet use and no complications related to intra-arterial catheters. In pediatric patients with OI, intraoperative use of NIBP cuffs and tourniquets was not associated with iatrogenic fracture. There were no complications related to intra-arterial catheter use. Care should be used during the perioperative period to prevent fractures during body positioning. Level IV.

To assess and compare dexamethasone, lignocaine, and tramadol in reduction of propofol-induced vascular pain

Introduction: Propofol (2,6 di-isopropyl phenol) is a widely used agent for induction of anesthesia, although pain during its injection remains a concern for all anesthesiologists. Pain on intravascular injection of propofol is very incapacitating, and the trouble still remains and has never been eradicated. Materials and Methods: After taking approval from the Institutional Review Board, this randomized controlled study was conducted on patients undergoing elective surgeries under general anesthesia. Two hundred and ten adult patients of either sex aged 28–60 years weighing between 40 and 80 kg were included into three groups: Group L – received 60 mg of preservative-free lignocaine hydrochloride, Group D – received 12 mg of dexamethasone sodium phosphate, and Group T – received 100 mg of tramadol hydrochloride. Venous occlusion was done at the level of mid-fore-arm by inflating a noninvasive blood pressure cuff to a pressure of 60 mmHg. Study drug was then injected over 10 s by consultant who was blinded to the procedure. After 2 min of study drug, venous occlusion was released following which propofol 0.5 mg/kg was injected over 5 s. Spontaneous complaints of pain and behavioral signs which included facial grimace, arm withdrawal, vocal and verbal rating score were recorded by the second anesthesiologist who was unaware of the group allocation. Results: All three drugs reduced the intensity and severity of propofol-induced vascular pain. Incidence of pain in lignocaine, dexamethasone, and tramadol Groups were 15%, 32.8%, and 31.4%, respectively. There was significant pain relief (P = 0.045 and 0.042, respectively) when comparing Group L and D, Group L and T. Pain relief between Group D and T was statistically similar (P = 0.8). The incidence of hand withdrawal was significantly higher in the tramadol group (P Conclusion: Use of pretreatment with drugs is required to prevent propofol-induced vascular pain. Both tramadol and dexamethasone are equally efficacious in reducing propofol-induced vascular pain, though both are less effective when compared with lignocaine. Dexamethasone has an added advantage of preventing postoperative nausea and vomiting when compared with both lignocaine and tramadol.

Validation of noninvasive blood pressure equipment: which peripheral artery is best for comparison studies in dogs?

Objectives1) To determine which peripheral artery commonly used for invasive arterial blood pressure (IBP) monitoring yields the least bias when compared with noninvasive blood pressure (NIBP) values obtained at the antebrachium of the dog, and 2) to identify and describe differences in systolic (SAP), mean (MAP) and diastolic arterial pressures (DAP) among different anatomical locations. Study designProspective experimental study. AnimalsTwenty adult hound dogs weighing 24.5 ± 1.1 kg (mean ± standard deviation). MethodsFour peripheral arteries—dorsal pedal, median caudal, intermediate auricular and superficial palmar arteries—were catheterized with 20 gauge, 3.8 cm catheters. One NIBP cuff was placed in the middle third of the antebrachium. Four sets of IBP and NIBP measurements were simultaneously collected every 2 minutes. A linear mixed model was performed to analyze the collected data. ResultsIBP values varied depending on the arterial catheterization site. The difference was greater for SAP. NIBP measured at the antebrachium had the best agreement with IBP measured at the median caudal artery. Conclusion and clinical relevanceIBP varies among anatomical locations. The smallest bias and narrowest limits of agreement were obtained at the median caudal artery, providing the best overall agreement with the equipment studied. The median caudal artery may be the preferable anatomical location for clinical comparison studies between IBP and NIBP in dogs when the cuff is on the antebrachium.

Comparison of arterial blood pressure measurements obtained invasively or oscillometrically using a Datex S/5 Compact monitor in anaesthetised adult horses

ObjectiveTo assess agreement between noninvasive blood pressure (NIBP) oscillometrically-derived values from a multiparameter monitor (Datex Ohmeda S/5 Compact) with those obtained by invasive blood pressure (IBP) measurement in anaesthetised horses undergoing elective surgery. Study designProspective clinical study. AnimalsA total of 40 healthy adult horses. MethodsHorses were anaesthetised with various anaesthetic protocols (based on clinical requirements). Depending on positioning, cannulation of the facial or lateral metatarsal artery was performed for IBP measurement. The cannula was connected via a transducer to the monitor. An appropriately sized NIBP cuff was placed around the tail base and connected to the same monitor. Systolic (SAP), mean (MAP) and diastolic (DAP) arterial blood pressures were continuously recorded from the invasive system, and at 3 minute intervals from the oscillometric system, throughout the surgical procedure using a Datex iCollect program. An appropriate arithmetic correction factor was applied to the oscillometric results where the cuff was not level with the heart. Assessment of the degree of agreement between invasive and noninvasive readings at each time point was performed using a modified Bland-Altman analysis. ResultsWhile in many horses there was relatively close correlation between the values obtained over time, there was substantial variability in individual animals which resulted in wide Bland-Altman limits of agreement. The oscillometric device over-reads by approximately 32, 23 and 22 mmHg, and under-reads by 26, 17 and 19 mmHg for SAP, MAP and DAP, respectively, compared with the IBP values. However, using the mean difference and standard deviation, the device conforms to American College of Veterinary Internal Medicine (ACVIM) standards. Conclusions and clinical relevanceOscillometric blood pressure measurement using the Datex Ohmeda S/5 Compact multiparameter monitor conforms to ACVIM standards when the NIBP cuff is placed on the tail. However, because of the wide variability in measurements, we cannot recommend this technique to guide therapy in anaesthetised adult horses.

Agreement between two oscillometric blood pressure technologies and invasively measured arterial pressure in the dog

ObjectivesTo compare two commonly used oscillometric technologies for obtaining noninvasive blood pressure (NIBP) measurements and to determine if there is a difference in agreement between these systems and invasive blood pressure (IBP) measurements. Study designProspective, experimental study. AnimalsTwenty adult laboratory dogs. MethodsEach dog was anesthetized and its median caudal artery catheterized for IBP monitoring. An NIBP cuff was placed in the middle third of the antebrachium and attached to either monitor-1 or monitor-2. Four pairs of concurrent NIBP and IBP measurements were recorded with each monitor. Agreement between IBP and NIBP measurements was explored using Bland–Altman analysis, as well as the American College of Veterinary Internal Medicine (ACVIM) and Association for the Advancement of Medical Instrumentation (AAMI) guidelines for the validation of NIBP devices. ResultsBoth NIBP technologies produced results that met the ACVIM and AAMI guidelines for the validation of NIBP devices. For monitor-1, analyses of agreement showed biases of 0.2 mmHg [95% limits of agreement (LoA) -11.8 to 12.3 mmHg] in systolic arterial pressure (SAP) values, -2.6 mmHg (95% LoA -14.4 to 9.1 mmHg) in diastolic arterial pressure (DAP) values, and -2.5 mmHg (95% LoA -12.7 to 7.3 mmHg) in mean arterial pressure (MAP) values. For monitor-2, analyses of agreement showed biases of 3.4 mmHg (95% LoA -8.7 to 15.5 mmHg) in SAP values, 2.2 mmHg (95% LoA -6.6 to 10.9 mmHg) in DAP values, and 1.6 mmHg (95% LoA -5.9 to 8.9 mmHg) in MAP values. Conclusions and clinical relevanceMulti-function monitors can contain components from various manufacturers. Clinicians should consider whether these have been validated in the species to be monitored. Both of the technologies studied here seem appropriate for use in dogs.

Abdominal insufflation for laparoscopy increases intracranial and intrathoracic pressure in human subjects.

Laparoscopy has emerged as an alternative to laparotomy in select trauma patients. In animal models, increasing abdominal pressure is associated with an increase in intrathoracic and intracranial pressures. We conducted a prospective trial of human subjects who underwent laparoscopic-assisted ventriculoperitoneal shunt placement (lap VPS) with intraoperative measurement of intrathoracic, intracranial and cerebral perfusion pressures. Ten patients undergoing lap VPS were recruited. Abdominal insufflation was performed using CO2 to 0, 8, 10, 12 and 15mmHg. ICP was measured through the ventricular catheter simultaneously with insufflation and with desufflation using a manometer. Peak inspiratory pressures (PIP) were measured through the endotracheal tube. Blood pressure was measured using a noninvasive blood pressure cuff. End-tidal CO2 (ETCO2) was measured for each set of abdominal pressure level. Pressure measurements from all points of insufflation were compared using a two-way ANOVA with a post hoc Bonferroni test. Mean changes in pressures were compared using t test. ICP and PIP increased significantly with increasing abdominal pressure (both p<0.01), whereas cerebral perfusion pressure (CPP) and mean arterial pressure did not significantly change with increasing abdominal pressure over the range tested. Higher abdominal pressure values were associated with decreased ETCO2 values. Increased ICP and PIP appear to be a direct result of increasing abdominal pressure, since ETCO2 did not increase. Though CPP did not change over the range tested, the ICP in some patients with 15mmHg abdominal insufflation reached values as high as 32cmH2O, which is considered above tolerance, regardless of the CPP. Laparoscopy should be used cautiously, in patients who present with baseline elevated ICP or head trauma as abdominal insufflation affects intracranial pressure.

The impact of blood pressure cuff location on the accuracy of noninvasive blood pressure measurements in obese patients: an observational study.

Obesity presents many challenges to the anesthesiologist, including poorly fitting blood pressure (BP) cuffs due to the conical shape of the upper arm. The aim of this study was to determine the accuracy of noninvasive BP readings, obtained from a noninvasive BP cuff using various cuff locations and wrapping techniques, compared with invasive intra-arterial BP readings. Thirty American Society of Anesthesiologists physical status I-III obese (body mass index > 30 kg·m(-2)) individuals undergoing non-cardiac surgery were enrolled in this observational study. Serial oscillometric noninvasive BP (NIBP) measurements were taken in the patients' forearm and upper arm with two different wrapping formations (one following the contour of the upper arm, the other keeping cuff edges parallel). These NIBP measurements were compared with invasive arterial blood pressure (ABP) measurements taken from the ipsilateral radial artery. The precision and bias of the NIBP and ABP measurements were determined using Bland-Altman analysis. Analysis of variance and Welch's t test were used to determine between-group differences in bias. There was poor agreement between the ABP measurements and all types of NIBP measurements. Each of our study participants had a least one NIBP parameter (mean arterial pressure, systolic BP, or diastolic BP) that was > 10 mmHg different than the corresponding ABP parameter. Upper arm BP measurements showed a statistically insignificant trend toward underestimating ABP. For all cuff positions and wrapping techniques, systolic BP offered the best agreement between NIBP and ABP measurements. All the forms of NIBP cuff orientation studied had unacceptable precision and bias compared with invasive ABP measurements. When patient and/or surgical conditions necessitate accurate BP monitoring, direct arterial measurement should be considered over NIBP measurements in obese patients.

A Simple Technique to Prevent Reverse Flow of Blood From Intravenous Line in Ipsilateral Arm with Noninvasive Blood Pressure Cuff.

To The Editor, In clinical practice, many a times, the patient has intravenous infusion line in situ while the non-invasive blood pressure cuff is applied on the same arm for periodic blood pressure monitoring. However, sometimes the cuff is deliberately tied in the same arm with the intravenous line, like in instances of surgery on the other arm, axilla or breast. It is of common observation that while the arm cuff is being inflated to monitor the blood pressure, there is reverse blood flow from the intravenous line towards the infusion bottle/bag [Table/Fig-1]. Occasionally, the reverse blood flow is so intense it reaches upto the infusion bag or bottle and colours the whole fluid red. Though there is no harm to the patient However, visualization of blood in the infusion line flowing in the reverse direction gives unpleasant feeling to the patient, attendants and the nursing staff. [Table/Fig-1]: Showing reverse flow of venous blood towards the infusion bag while blood pressure cuff is inflated We offer a simple and novel solution. While tying the blood pressure cuff in upper arm, the tubing of the infusion set may be passed through two folds of the cuff [Table/Fig-2]. If infusion tube is short, another extension tube may be added. When the cuff is inflated, there is no back flow of venous blood in the infusion line. During the cuff inflation, the pressure exerted by inflated cuff over the collapsible tubing of infusion set causes compression and total occlusion of the lumen and thereby prevents backflow of intravenous blood. We have used this technique in more than 100 patients and not encountered any adverse effect (eg. disconnection of cannula or extravasation of fluid at the cannula site). [Table/Fig-2]: The tubing of the infusion set is passed between two folds of cuff tied in the arm. Note, there is no reverse flow of venous blood on cuff inflation This is our own experience. We have been practicing this simple technique, whenever required, to prevent reverse blood flow from the intravenous line and wish to disseminate this practice so that others may benefit. The technique is very simple to practice and is quite effective in prevention of reverse flow of blood from the venous line towards the infusion bag. However, a large scale prospective study is required to validate the method and ascertain its safety.

Airway management of a huge thyroid swelling with retrosternal extension by awake intubation using loco-sedative technique

To the Editor, The anesthesiologist approaching the patient with a difficult airway has got many techniques and instruments that can be applied for securing and maintaining oxygenation and ventilation.[1234] We report here the airway management of a patient with massive thyroid swelling accompanied by tracheal narrowing, deviation and retrosternal extension. The patient was posted for total thyroidectomy. A 43-year-old female patient presented with a history of the diffuse neck swelling since 5 years with recent onset of dyspnea. There was no suggestive history of hyper or hypothyroidism. On examination, her vital parameters were normal, and she was neither in distress nor sweating. Neck examination showed a huge swelling of around 8 cm × 4 cm on the right side and 6 cm × 4 cm on the left side. It was moving with swallowing, firm in consistency but not tender. Getting below the swelling was not possible. Cardiovascular system examination revealed no added sounds or murmurs. Chest examination showed bilateral good air entry. Laboratory investigation including thyroid function tests were within normal ranges. Radiological examination including Chest X-ray and magnetic resonance imaging (MRI) revealed diffusely enlarged thyroid gland with left lobe measuring 11.2 × 7.5 × 5.5 cms in size with retrosternal extension and right lobe measuring 8.5 × 6.2 × 4.5 cms in size with inferior margin of right lobe just above sternum associated with superior mediastinal widening, significant compression and displacement of trachea to right side. Carotid artery and jugular vein were displaced laterally on both sides of neck. There was no tracheal erosion or infiltration [Figure 1]. On IDL, larynx was not seen and with 70 degree scope, larynx was pushed to right with normal and mobile bilateral vocal cords. Fine-needle aspiration cytology showed possibility of benign follicular lesion. Airway assessment revealed adequate mouth opening with Mallampati Grade II, but limited neck movement. The plan was to perform awake endotracheal intubation through direct laryngoscopy.Figure 1: Magnetic resonance imaging plate showing huge swelling with retrosternal extensionPremedication was achieved with injection glycopyrrolate 0.2 mg intramuscular and injection midazolam 1 mg intravenous (iv) followed by nebulization with lignocaine (2%) solution and lignocaine (2%) viscus gargles. In the operation theater, the difficult airway cart was arranged and noninvasive blood pressure cuff, SpO2 and electrocardiogram were attached to the patient. Injection dexmedetomidine bolus was started at 1 mcg/kg over 10 min, followed by infusion at 0.6 mcg/kg/h along with which preoxygenation was done with 100% oxygen. When the sedation score was Ramsay score 3, direct laryngoscopy was performed and lignocaine (5%) spray was puffed and after 5 min trachea was intubated successfully with 7.5 mm size armored tube with external manipulation of larynx. Intubation was confirmed by attaching EtCO2 monitor, which was followed by IV injection of propofol and injection vecuronium. Anesthesia was maintained with incremental doses of vecuronium and sevoflurane. Total thyroidectomy was uneventful. On completion of surgery, neuromuscular blockade was reversed and trachea was extubated after performing leak test to rule out any possibility of tracheomalacia. The problems anticipated during induction were difficult mask ventilation after induction of general anesthesia and muscle relaxation secondary to partial or complete airway collapse by huge thyroid swelling, which can cause severe hypoxia and warrants urgent tracheal intubation which may be difficult and time consuming due to distorted anatomy.[234] In this situation, it was prudent to secure the airway before induction of anesthesia. Awake fiberoptic intubation is ideal gold standard technique in such situation where intubation is done under direct visualization of the glottis.[1] Fiberoptic bronchoscope was not available in our institute so awake oral intubation with direct laryngoscopy was planned. Dexmedetomidine is selective ά2 agonist with pharmacological actions like analgesia, anxiolysis, sedation, reduction in the secretion, sympatholytic action, minimal respiratory depression, decreased stress response to intubation and attenuation of airway reflexes making it promising agent in this situation.[5] Hence dexmedetomidine in bolus and infusion was used during induction to enhance patient comfort and cooperation, which is essential for the success of awake intubation using direct laryngoscopy. In conclusion, awake intubation using topical anesthesia and sedation with dexmedetomidine infusion is a viable option in case of huge thyroid swelling. Acknowledgments A deep regards and my profound gratitude to Department of Otorhinolaryngology, New Civil Hospital, Surat for providing all help with patient's details and MRI picture of the patient.

Forearm Loss Caused by Automated Non-Invasive Blood Pressure Cuff Malfunction: A Hearsay Report

Failure of an automated blood pressure cuff to deflate when a patient is under general anesthesia can lead to catastrophic consequences if unnoticed for more than three hours [1]. We present this as a hearsay case in which an automated blood pressure cuff of the Spacelabs Ultraview Clinical Workstation monitor (model No. 90385) applied pressure for about five hours resulting in limb thrombosis. In order to analyze this catastrophe, simulation scenarios were tested to elucidate the possible errors and malfunctions that may have led to this injury. We present the analysis of the advantages and validity of the hearsay case report. We also include our proposed criteria that should be required when a hearsay case is considered for publication.

Use of Arterial Catheters in the Management of Acute Aortic Dissection

PurposeThe aim of this study was to investigate the relationship between the use of invasive arterial blood pressure (IBP) monitoring and reaching established aggressive medical management goals in acute aortic dissection. MethodsData were collected through a retrospective chart review of patients diagnosed with acute aortic syndromes of the thoracic cavity who required transport to tertiary care over a 28-month period. The 2010 American Heart Association medical management goals of thoracic aortic disease were used as hemodynamic end points. ResultsA total of 208 patients were included, with 113 (54%) diagnosed at least in part with acute Stanford Type A aortic dissections and the remaining 95 (46%) having isolated Stanford Type B dissections. Emergency departments made up 158 (76%) of transfer departments; 129 (62%) patients had IBP catheters placed. The highest mean systolic blood pressures (SBPs) recorded were 165 mm Hg in the IBP group versus 151 mm Hg when noninvasive blood pressure (NIBP) cuffs were used (P < .01). The mean decrease in SBP during transport was 51 mm Hg in the IBP group versus 34 mm Hg in the NIBP group (P < .001). The difference between the last reported NIBP and the first IBP was noted as 19 mm Hg higher. The IBP group met the SBP goal more frequently than the NIBP group (P < .05) when the SBP was noted as greater than 140 mm Hg during transport. Bedside time increased only 6 minutes with IBP placement (P < .007). ConclusionPatients with IBP catheters were noted to be more aggressively managed with antihypertensive medications, met hemodynamic goals more frequently, and had only 6 minutes longer bedside times. These findings support the placement of IBP catheters by emergency departments and critical care transport (CCT) teams in patients with acute aortic syndromes requiring interfacility transport to definitive care.

Fluctuations in vital signs and behavioural responses of brain surgery patients in the Intensive Care Unit: are they valid indicators of pain?

To examine the validity of behaviours and fluctuations in vital signs for pain assessment of postbrain surgery adults in the neurosurgical intensive care unit. Many patients in an intensive care unit may be unable to self-report their pain. In such cases, the use of observable indicators is recommended. Very little research has explored the validity of the use of behaviours and vital signs for pain assessment of neurocritically ill patients. Prospective repeated-measure within-subject observational design. A total of 43 postbrain surgery patients were video recorded before, during and 15 minutes after a non-nociceptive (non-invasive blood pressure cuff inflation) and a nociceptive (turning) procedures. Their behaviours and vital signs were collected with a pre-tested behavioural checklist and a data collection computer connected to the bedside monitor. The patients' self-report of pain was obtained whenever possible. Data were collected between June-December in 2011. A larger number of pain-related behaviours were exhibited by participants during the nociceptive procedure compared with the non-nociceptive procedure supporting discriminant validation. Among vital signs, only respiratory rate differed significantly between the two procedures. Regarding criterion validation, only behaviours were positively correlated with self-reports of pain. Behaviours were found valid indicators of pain in neurocritically ill patients after elective brain surgery. Fluctuations in vital signs may suggest the presence of pain, but their validity for such use is not supported. They should only be used in combination with other validated pain assessment methods.