New-Generation Pulse Oximetry in the Care of Critically Ill Patients

Comparative analysis of signal accuracy of three SpO2 monitors during motion and low perfusion conditions

To compare pulse oximetry performance during simulated conditions of motion and low perfusion in three commercially available devices: GE HealthCare CARESCAPE ONE TruSignal SpO2 Parameter, Masimo RADICAL-7 and Medtronic Nellcor PM1000N. After IRB approval, 28 healthy adult volunteers were randomly assigned to the motion group (N = 14) or low perfusion (N = 14) group. Pulse oximeters were placed on the test and control hands using random assignment of digits 2-5. Each subject served as their own control through the series of repeated pair-wise measurements. Reference co-oximetry oxyhemoglobin (SaO2) measurements from the radial artery were also obtained in the motion group. SpO2 readings were compared between the test and control hands in both groups and to SaO2 measurements in the motion group. Accuracy was assessed through testing of accuracy root-mean squared (ARMS) and mean bias. In the simulated motion test group the overall Accuracy Root Mean Square (ARMS) versus SaO2 was 1.88 (GE), 1.79 (Masimo) and 2.40 (Nellcor), with overall mean bias of - 0.21 (Masimo), 0.45 (GE), and 0.78 (Nellcor). In the motion hand, ARMS versus SaO2 was 2.45 (GE), 3.19 (Masimo) and 4.15 (Nellcor), with overall mean bias of - 0.75 (Masimo), - 0.01 (GE), and 0.04 (Nellcor). In the low perfusion test group, ARMS versus the control hand SpO2 for low PI was 3.24 (GE), 3.48 (Nellcor) and 4.76 (Masimo), with overall bias measurements of - 0.53 (Nellcor), 0.96 (GE) and 1.76 (Masimo). Experimental results for all tested devices met pulse oximetry regulatory and testing standards requirements. Overall, SpO2 device performance across the three devices in this study was similar under both motion and low perfusion conditions. SpO2 measurement accuracy degraded for all three devices during motion as compared to non-motion. Accuracy also degraded during normal to low, very low, or ultra low perfusion and was more pronounced compared to the changes observed during simulated motion. While some statistically significant differences in individual measurements were found, the clinical relevance of these differences requires further study.

Blood oxygenation response to aerobic exercise combined with breathing exercises in pregnant women: a randomized controlled trial

Background

There are many physiological changes occur during pregnancy that affect oxygenation of the pregnant women. It was considered that aerobic and breathing exercises are safe for the mother and the fetus especially moderate intensity exercise during pregnancy.

Objective

This study was designed to investigate the blood oxygenation response to aerobic exercise combined with breathing exercises in pregnant women.

Methodology

Forty pregnant women were selected from obstetrics and gynecology outpatient clinic at Kasr El Einy Hospital, Egypt, confidentiality was assured. They were ranged from 25 to 30 years old, with body mass index (BMI) less than 30 kg/m2 and at the beginning of 3rd trimester, this study was conducted from September 2019 to April 2020. They were assigned into two groups: group A performed aerobic exercise in a form of walking for 20 min. On the treadmill at 60–75% of the maximum heart rate (MHR) of each woman, three times per week in addition to deep breathing exercises in form of diaphragmatic and lateral costal breathing; group B who performed deep breathing exercises only in form of diaphragmatic and lateral costal breathing. The program continued for three months, three times per week. The oxygen saturation (SaO2) was measured twice time, firstly, at the beginning of 3rd trimester of pregnancy then after three months of treatment program.

Results

The results of this study revealed a statistically significant difference in the oxygen saturation in group A than in group B.

Conclusion

It could be concluded that there was significant statistical effect of aerobic exercise combined with breathing exercises on blood oxygenation in pregnant women. It improved the oxygen saturation in pregnant women.

Pulse Arrival Time Is Associated With Hemorrhagic Volume in a Porcine Model: A Pilot Study

BACKGROUND

Hemorrhage is a major cause of preventable death worldwide, and early identification can be lifesaving. Pulse wave contour analysis has previously been used to infer hemodynamic variables in a variety of settings. We hypothesized that pulse arrival time (PAT), a form of pulse wave contour analysis which is assessed via electrocardiography (ECG) and photoplethysmography (PPG), is associated with hemorrhage volume.

METHODS

Yorkshire-Cross swine were randomized to hemorrhage (30 mL/kg over 20 minutes) vs. control. Continuous ECG and PPG waveforms were recorded with a novel monitoring device, and algorithms were developed to calculate PAT and PAT variability throughout the respiratory cycle, termed "PAT index" or "PAT_I." Mixed effects models were used to determine associations between blood loss and PAT and between blood loss and PAT_I to account for clustering within subjects and investigate inter-subject variability in these relationships.

RESULTS

PAT and PAT_I data were determined for ∼150 distinct intervals from five subjects. PAT and PAT_I were strongly associated with blood loss. Mixed effects modeling with PAT alone was substantially better than PAT_I alone (R2 0.93 vs. 0.57 and Akaike information criterion (AIC) 421.1 vs. 475.5, respectively). Modeling blood loss with PAT and PAT_I together resulted in slightly improved fit compared to PAT alone (R2 0.96, AIC 419.1). Mixed effects models demonstrated significant inter-subject variability in the relationships between blood loss and PAT.

CONCLUSIONS

Findings from this pilot study suggest that PAT and PAT_I may be used to detect blood loss. Because of the simple design of a single-lead ECG and PPG, the technology could be packaged into a very small form factor device for use in austere or resource-constrained environments. Significant inter-subject variability in the relationship between blood loss and PAT highlights the importance of individualized hemodynamic monitoring.

The Use of Pulse Oximetry in the Assessment of Acclimatization to High Altitude

Background: Finger pulse oximeters are widely used to monitor physiological responses to high-altitude exposure, the progress of acclimatization, and/or the potential development of high-altitude related diseases. Although there is increasing evidence for its invaluable support at high altitude, some controversy remains, largely due to differences in individual preconditions, evaluation purposes, measurement methods, the use of different devices, and the lacking ability to interpret data correctly. Therefore, this review is aimed at providing information on the functioning of pulse oximeters, appropriate measurement methods and published time courses of pulse oximetry data (peripheral oxygen saturation, (SpO₂) and heart rate (HR), recorded at rest and submaximal exercise during exposure to various altitudes. Results: The presented findings from the literature review confirm rather large variations of pulse oximetry measures (SpO₂ and HR) during acute exposure and acclimatization to high altitude, related to the varying conditions between studies mentioned above. It turned out that particularly SpO₂ levels decrease with acute altitude/hypoxia exposure and partly recover during acclimatization, with an opposite trend of HR. Moreover, the development of acute mountain sickness (AMS) was consistently associated with lower SpO₂ values compared to individuals free from AMS. Conclusions: The use of finger pulse oximetry at high altitude is considered as a valuable tool in the evaluation of individual acclimatization to high altitude but also to monitor AMS progression and treatment efficacy.

Challenging Precedent: Critical Care Nursing and Medical Product Innovation

In this presentation, I will share my unconventional journey, starting from my first job as a critical care staff nurse to my current role as tenure-track faculty at the University of Massachusetts Amherst, where I hold a joint position with the Institute for Applied Life Sciences and the College of Nursing. Throughout this journey, I have had many opportunities to participate in interdisciplinary clinical outcomes research and medical product development as a staff nurse, clinical nurse specialist, and project lead from the clinical, industry, and academic perspectives. While passionate about my central clinical research interests in technology innovation and its responsible use in critical and acute care, the foundation of my approach is dedicated to the values and lessons of my earliest experiences in critical care bedside nursing: supporting and preserving the dignity and humanity of person-centered patient care. Early in my career as a critical care nurse, I realized how vitally important a critical care nursing perspective could be in the design of technology for meeting the critical care needs of patients, nurses, and other professionals who provide this care. As the nation's largest group of health care professionals, nurses use more products than any other health care professional, and thus nurses have a uniquely practical and care-sensitive perspective on the development and design of medical products. Nurses, especially critical care nurses, are in a unique position to identify and address everyday health care issues, challenge assumptions and the status quo, address unrecognized and unarticulated needs, and ensure that clinical outcomes research serves as the foundation for validating the effectiveness of medical product innovation. My goal is to share lessons learned and to help participants to see the many different ways that critical care nursing knowledge can be used to improve patient care.

Four Types of Pulse Oximeters Accurately Detect Hypoxia during Low Perfusion and Motion

Background

Pulse oximeter performance is degraded by motion artifacts and low perfusion. Manufacturers developed algorithms to improve instrument performance during these challenges. There have been no independent comparisons of these devices.

Methods

We evaluated the performance of four pulse oximeters (Masimo Radical-7, USA; Nihon Kohden OxyPal Neo, Japan; Nellcor N-600, USA; and Philips Intellivue MP5, USA) in 10 healthy adult volunteers. Three motions were evaluated: tapping, pseudorandom, and volunteer-generated rubbing, adjusted to produce photoplethsmogram disturbance similar to arterial pulsation amplitude. During motion, inspired gases were adjusted to achieve stable target plateaus of arterial oxygen saturation (SaO2) at 75%, 88%, and 100%. Pulse oximeter readings were compared with simultaneous arterial blood samples to calculate bias (oxygen saturation measured by pulse oximetry [SpO2] − SaO2), mean, SD, 95% limits of agreement, and root mean square error. Receiver operating characteristic curves were determined to detect mild (SaO2 < 90%) and severe (SaO2 < 80%) hypoxemia.

Results

Pulse oximeter readings corresponding to 190 blood samples were analyzed. All oximeters detected hypoxia but motion and low perfusion degraded performance. Three of four oximeters (Masimo, Nellcor, and Philips) had root mean square error greater than 3% for SaO2 70 to 100% during any motion, compared to a root mean square error of 1.8% for the stationary control. A low perfusion index increased error.

Conclusions

All oximeters detected hypoxemia during motion and low-perfusion conditions, but motion impaired performance at all ranges, with less accuracy at lower SaO2. Lower perfusion degraded performance in all but the Nihon Kohden instrument. We conclude that different types of pulse oximeters can be similarly effective in preserving sensitivity to clinically relevant hypoxia.

Comparison of Oxygen Saturation During Impression Taking Before and After Presurgical Orthopedic Therapy in Babies With Cleft Lip and Palate

AIM

The objective of this study was to (1) evaluate the oxygen saturation (SpO₂) levels during intraoral and extraoral impression taking and (2) compare the SpO₂ levels during impression taking before and after presurgical orthopedic therapy (POT) of infants with cleft lip and palate (CLP).

PATIENTS AND METHODS

In our study, 31 babies with CLP before (mean age 7.6 ± 3.2 days) and after (mean age 108.3 ± 24.2 days) POT were monitored, and SpO₂ levels were measured under operating conditions before any intervention (T1), after oxygenation (T2), during taking intraoral (T3), and extraoral (T4) impressions with oxygen support and immediately before the discharge from the operating room (T5).

RESULTS

In both groups, statistically significant differences in SpO₂ measurements at T1, T2, T3, T4, and T5 stages were found (P < .01). For the pre-POT measurements, increases in SpO₂ levels from T1 to T2 and T4 to T5 (P < .05) and decreases from T2 to T3 and T3 to T4 (P < .01) were noted. Similarly, SpO₂ levels decreased significantly from the intraoral (T3) to extraoral (T4) post-POT impression periods (P < .01). Comparisons of pre- and post-POT measurements revealed that the SpO₂ level of each time period was higher at the post-POT impression taking except for stages T2 and T5 (P < .01).

CONCLUSION

The SpO₂ values were low at the onset of POT in infants with CLP before any intervention. Oxygen saturation levels may decrease particularly during extraoral impression taking in infants with CLP despite the supplemental oxygen. SpO₂ measurements were higher during post-POT intraoral and extraoral impression taking when compared with pre-POT measurements.

Design and Construction of a Microcontroller-Based Ventilator Synchronized with Pulse Oximeter

This study aims to introduce a novel device with which mechanical ventilator and pulse oximeter work in synchronization. Serial communication technique was used to enable communication between the pulse oximeter and the ventilator. The SpO2 value and the pulse rate read on the pulse oximeter were transmitted to the mechanical ventilator through transmitter (Tx) and receiver (Rx) lines. The fuzzy-logic-based software developed for the mechanical ventilator interprets these values and calculates the percentage of oxygen (FiO2) and Positive End-Expiratory Pressure (PEEP) to be delivered to the patient. The fuzzy-logic-based software was developed to check the changing medical states of patients and to produce new results (FiO2 ve PEEP) according to each new state. FiO2 and PEEP values delivered from the ventilator to the patient can be calculated in this way without requiring any arterial blood gas analysis. Our experiments and the feedbacks from physicians show that this device makes it possible to obtain more successful results when compared to the current practices.

Complementary home mechanical ventilation techniques. SEPAR Year 2014

This is a review of the different complementary techniques that are useful for optimizing home mechanical ventilation (HMV). Airway clearance is very important in patients with HMV and many patients, particularly those with reduced peak cough flow, require airway clearance (manual or assisted) or assisted cough techniques (manual or mechanical) and suctioning procedures, in addition to ventilation. In the case of invasive HMV, good tracheostomy cannula management is essential for success. HMV patients may have sleep disturbances that must be taken into account. Sleep studies including complete polysomnography or respiratory polygraphy are helpful for identifying patient-ventilator asynchrony. Other techniques, such as bronchoscopy or nutritional support, may be required in patients on HMV, particularly if percutaneous gastrostomy is required. Information on treatment efficacy can be obtained from HMV monitoring, using methods such as pulse oximetry, capnography or the internal programs of the ventilators themselves. Finally, the importance of the patient's subjective perception is reviewed, as this may potentially affect the success of the HMV.

Oxygen therapy and oximetry in the delivery room

Pulse oximetry is increasingly being used in the delivery room. Expert recommendations state that oxygen therapy during newborn resuscitation should be guided by pulse oximetry. Obtaining accurate and stable oxygen saturation and heart rate information from a pulse oximeter in the delivery room can be challenging. Understanding the properties of this device is important in overcoming these challenges. This article describes several aspects of pulse oximetry use in the delivery room ranging from technical issues with the device itself to clinical applications of the technology.

[Nocturnal monitoring of home non-invasive ventilation: Contribution of simple tools such as pulse-oximetry, capnography, built-in ventilator software and autonomic markers of sleep fragmentation]

Complex respiratory events, which may have a detrimental effect on both quality of sleep and control of nocturnal hypoventilation, occur during sleep in patients treated by non-invasive ventilation (NIV). Among these events are patient-ventilator asynchrony, increases in upper airway resistance with or without increased respiratory drive, and leaks. Detection of these events is important in order to select the most appropriate ventilator settings and interface. Simple tools can provide important information when monitoring NIV. Pulse-oximetry is important to ensure that an adequate SpO2 is provided, and to detect either prolonged or short and recurrent desaturations. However, the specificity of pulse-oximetry tracings under NIV is low. Transcutaneous capnography discriminates between hypoxemia related to V/Q mismatch and hypoventilation, documents correction of nocturnal hypoventilation, and may detect ventilator-induced hyperventilation, a possible cause for central apnea/hypopnea and glottic closure. Data provided by ventilator software helps the clinician by estimating ventilation, tidal volume, leaks, rate of inspiratory or expiratory triggering by the patient, although further validation of these signals by independent studies is indicated. Finally, autonomic markers of sympathetic tone using signals such as pulse wave amplitude of the pulse-oximetry signal can provide reliable information of sleep fragmentation.

The feasibility and validity of a remote pulse oximetry system for pulmonary rehabilitation: a pilot study

Pulmonary rehabilitation is an effective treatment for people with chronic obstructive pulmonary disease. However, access to these services is limited especially in rural and remote areas. Telerehabilitation has the potential to deliver pulmonary rehabilitation programs to these communities. The aim of this study was threefold: to establish the technical feasibility of transmitting real-time pulse oximetry data, determine the validity of remote measurements compared to conventional face-to-face measures, and evaluate the participants' perception of the usability of the technology. Thirty-seven healthy individuals participated in a single remote pulmonary rehabilitation exercise session, conducted using the eHAB telerehabilitation system. Validity was assessed by comparing the participant's oxygen saturation and heart rate with the data set received at the therapist's remote location. There was an 80% exact agreement between participant and therapist data sets. The mean absolute difference and Bland and Altman's limits of agreement fell within the minimum clinically important difference for both oxygen saturation and heart rate values. Participants found the system easy to use and felt confident that they would be able to use it at home. Remote measurement of pulse oximetry data for a pulmonary rehabilitation exercise session was feasible and valid when compared to conventional face-to-face methods.

"New-generation" pulse oximeters in extremely low-birth-weight infants: how do they perform in clinical practice?

The aim of this study was to evaluate the performance of "new-generation" pulse oximeters in extremely low-birth-weight ([ELBW] ≤ 1000 g) infants. In a prospective crossover observational study, the performance of pulse oximeters of 3 brands (Masimo, Nellcor, and Philips) was evaluated by dual SpO2 measurement in ELBW infants. Disposable probes of either equal or different brands were placed around both feet of the patient simultaneously for approximately 4 hours. Probes were switched between feet every hour. Absolute differences in SpO2 values (ΔSpO2) and the bias between brands were studied. Nine ELWB infants were included (gestational age: mean ± SD = 26(3)/7 ± 1 4/7 weeks). The median (range) ΔSpO2 was 2% (0%-26%). In 9% of the time, ΔSpO2 was 5% or more. The variance of the difference of the 3 pulse oximeter brands was not significantly different. No consequent bias between brands was found. Simultaneously obtained pulse oximeter measurements from the feet of ELBW infants differ from each other. Our results suggest that it is not the brand but the handling of the pulse oximeter in clinical practice, such as the place and positioning of the probe, that influences the performance of the pulse oximeter the most. Improvement in the accuracy of oxygen-monitoring techniques for ELBW infants is required.

[Reliability of pulsatile saturometry in patients with shock. Digital standard sensors are not reliable for facial measurement!]

INTRODUCTION

Non-invasive monitoring of oxygen saturation by pulse oxymetry (SpO(2)) is sometimes perturbed on fingers during shock states. Other sites are possible (toes, forehead, nose, ear). Self-adhesive standard digital sensors are commonly used off-label in these sites. We have assessed their reliability for all of these sites.

METHODS

We have studied patients presenting a stabilized shock state and receiving vasoconstrictive catecholamines. When an arterial blood gas was ordered, six SpO(2) were measured quasi-simultaneously (self-adhesive standard sensors): right and left index, toe, forehead, nose and ear. SpO(2) at "finger", "toe", "forehead", "nose" and "ear" were compared to the arterial oxygen saturation (SaO(2)) by using the Bland and Altman method. The plethysmographic curve was assessed as "correct" or "unsatisfactory".

RESULTS

Hundred and ten patients were included (63 ± 15 years, SAPSII 46 ± 16, catecholamines: 0.6 ± 0.5 μg/kg/min). Plethysmographic curves are more often of "correct" quality for fingers (90%) than for the other locations (50 to 70%). Bias are low for all the locations (-0.1 to +1.5%). Limits of agreement are around ±5% for fingers and toes, but as high as ±15% for the face locations. When the analysis is restricted to plethysmographic curves of "good" quality, the limits of agreement are unchanged for fingers and toes, but improved (between ±5 to ±10%) for face locations.

CONCLUSION

In patients with a shock receiving vasoconstrictive catecholamines, the reliability of SpO(2) measurements with standard sensors appears better for fingers than for toes and face locations. These standard sensors should be discouraged for facial measurement because of their low reliability, even when the plethysmographic curve seems correct. Sensors specifically designed for each facial site exist, and their reliability should be estimated in patients receiving vasoconstrictive catecholamines.

An exploratory investigation of some statistical summaries of oximeter oxygen saturation data from preterm babies

Aim. To explore the potential usefulness of the mean, standard deviation (SD), and coefficient of variation (CV = SD/mean) of oximeter oxygen saturations in the clinical care of preterm babies. Methods. This was an exploratory investigation involving 31 preterm babies at 36 weeks postmenstrual age. All babies were healthy, but two were considered to be clinically unstable and required greater attention. Each baby's oxygen saturations were recorded using an oximeter and summarized by the mean, SD, and CV. The potential usefulness of each measure was assessed by its ability to distinguish the two unstable babies from the others. This was achieved using box plots and hierarchical clustering together with the Calinski-Harabasz (CH) index to quantify clustering performance (higher CH index indicates stronger clustering outcome). Results. The box plots flagged both unstable babies as outliers and none of the other babies. Successful clustering of the stable and unstable babies was achieved using the CV (CH = 72.8) and SD (CH = 63.3) but not with the mean. Conclusion. Taking the box plots and clustering results together, it seems plausible that variability might be more effective than mean level for detecting instability in oxygen saturation in preterm babies and that the combination of variability and level through the CV might be even better.

Pulse oximetry during intraaortic balloon pump application

BACKGROUND

Pulse oximeters are multiple used devices in anaesthesiology and intensive care medicine and must provide reliable data during various conditions of signal interference, including light, motion and reduced perfusion. The aim of this study was to evaluate the reliability of different new-generation pulse oximeters during intraaortic balloon pump (IABP) therapy.

METHODS

In the experimental setting, the validity of three pulse oximetry technologies (Masimo Radical 7, Nellcor N-600 and Datex Ohmeda TruSat) was evaluated in patients with IABP treatment. Arterial blood gas analysis (BGA-SaO2) data were compared with the pulse oximetric values (SpO2) during 1:1, 1:2 and 1:3 support ratio.

RESULTS

The mean differences (bias) during 1:1, 1:2 and 1:3 IABP support between BGA-SaO2 and Datex-SpO2 were 3.38% [95% confidence intervals (CI):±1.39%], 1.41% (95% CI 1.14%) and 2.10% (95% CI:±0.94%), respectively. Between BGA-SaO2 and Nellcor-SpO2, a bias of 0.77% (95% CI:±0.46%), 0.85% (95% CI:±0.40%) and 0.59% (95% CI:±0.38%) was found. In the comparison of BGA-SaO2 and Masimo-SpO2, a bias of 0.58% (95% CI:±0.56%), 0.19% (95% CI:±0.40%) and -0.01% (95% CI:±0.43%) was found, respectively.

CONCLUSIONS

In patients with IABP support, the pulse oximetric values of the Masimo Radical 7 are accurate in 1:2 and 1:3 support ratio compared with blood gas analysis. In these support ratios, the Masimo Radical 7 is superior to the Nellcor N-600. The Datex Ohmeda TruSat showed a significant difference between the measured pulse oximetric values and blood gas analysis in all support ratios.

Pulse oximetry in adults

Pulse oximetry, a straightforward method for estimating arterial oxygen saturation, can detect hypoxemia early; it's used often and in a variety of settings. But what's not always clear is how frequently-or even whether-patients should be monitored, and unless guidelines are understood and followed, pulse oximetry can be misused or overused. This article reviews the technology and its limitations and discusses current guidelines and their implications for nurses.

Evaluation of a New Pulse Oximeter Sensor

• Background A new forehead noninvasive oxygen saturation sensor may improve signal quality in patients with low cardiac index.

• Objectives To examine agreement between oxygen saturation values obtained by using digit-based and forehead pulse oximeters with arterial oxygen saturation in patients with low cardiac index.

• MethodsA method-comparison study was used to examine the agreement between 2 different pulse oximeters and arterial oxygen saturation in patients with low cardiac index. Readings were obtained from a finger and a forehead sensor and by analysis of a blood sample. Bias, precision, and root mean square differences were calculated for the digit and forehead sensors. Differences in bias and precision between the 2 noninvasive devices were evaluated with a t test (level of significance P&lt;.05).

• Results Nineteen patients with low cardiac index (calculated as cardiac output in liters per minute divided by body surface area in square meters; mean 1.98, SD 0.34) were studied for a total of 54 sampling periods. Mean (SD) oxygen saturations were 97% (2.4) for blood samples, 96% (3.2) for the finger sensor, and 97% (2.8) for the forehead sensor. By Bland Altman analysis, bias ± precision was −1.16 ± 1.62% for the digit sensor and −0.36 ± 1.74% for the forehead sensor; root mean square differences were 1.93% and 1.70%, respectively. Bias and precision differed significantly between the 2 devices; the forehead sensor differed less from the blood sample.

• Conclusions In patients with low cardiac index, the forehead sensor was better than the digit sensor for pulse oximetry.

Hand Pain During Hand Assisted Laparoscopic Nephrectomy—An Ischemic Event?

PURPOSE

The etiology of hand discomfort during hand assisted laparoscopic nephrectomy may be ischemic in nature. We determined if pneumoperitoneal pressure sustained to the hand during hand assisted laparoscopic nephrectomy poses an occupational risk, contributing to local hand hypoxia and resultant extremity pain.

MATERIALS AND METHODS

A total of 442 measurements of hand oxygen saturation were made during hand assisted laparoscopic nephrectomy. A Nellcor OxiMax Max-1 oxygen sensor was attached to the left index finger of each surgeon and hand assisted laparoscopic nephrectomy was performed using a LapDisc at 15 mm Hg pneumoperitoneal pressures. Local hand oximetry readings and a numerical pain distress scale (range 0 to 10) were recorded every 2 minutes. To control for motion artifact oximetry readings were taken during hand motion and at rest. The Student t test was used to compare differences in local hand oxygen saturation and hand pain in and between study groups.

RESULTS

A history of hand pain during hand assisted laparoscopic nephrectomy was significantly associated with local hypoxia during operative motion and at rest (p = 0.023 and 0.012, respectively), even with an adequate fascial incision and standard pneumoperitoneal pressures. During hand assisted laparoscopic nephrectomy hand pain was most significantly associated with local hypoxia after 24 minutes (p = 0.0002), when local oxygen saturation was 56% to 88%.

CONCLUSIONS

A cohort of urologists is predisposed to ischemic hand pain during hand assisted laparoscopic nephrectomy. The etiology of this pain may be hypoxic in nature, attributable to pneumoperitoneal pressure decreasing perfusion and causing venous congestion or regional local ischemia. Circumferential antebrachial constriction from the LapDisc does not seem to be a significant contributing factor in the presence of an adequate fascial incision. Hand pain secondary to ischemia is most significant after 24 minutes at 15 mm Hg. Future studies in more subjects are called for to validate these findings to elucidate which surgeons are predisposed to this potential occupational hazard and what perioperative measures can be taken to avoid hand pain during hand assisted laparoscopic nephrectomy.