Interventions to prevent hypothermia in extremely preterm low-weight infants undergoing cardiac catheterisation.

BACKGROUND: In January 2019, a new device called the Amplatzer Piccolo Occluder was approved by the US Food and Drug Administration for percutaneous closure of patent ductus arteriosus in infants weighing more than 700 g and of postnatal age more than 3 days. Premature low-weight infants are predisposed to hypothermia when transported outside of the thermo-neutral environment. At our institution, 90% of extremely preterm low-weight infants developed transient moderate hypothermia in the cardiac catheterisation suite. METHODS: We conducted a study testing multiple hypotheses aimed at preventing hypothermia in the cardiac catheterisation suite. Interventions included increasing ambient room temperature, reducing exposure to cold environment and reducing overall time spent in the remote location. The primary outcome was the proportion of patients who developed transient hypothermia at the start of the procedure in the cardiac catheterisation suite. The secondary measures included mean core body temperature at four different instances, as well as anaesthesia time, procedure time and radiation exposure. RESULTS: During the study period, 10 patients were enrolled in each group. The postintervention group saw a reduction in transient hypothermia from 90% to 40% (absolute risk reduction 50%, p=0.02). Data analysis showed an improvement in mean core body temperature (35.4°C vs 36.4°C, p<0.01) as well as a smaller percentage drop in temperature (4% vs 1.3%, p<0.01) between the two groups, both of which were statistically significant. The anaesthesia time, procedure time and radiation exposure reduced between the two groups. CONCLUSION: The application of the interventions reduced hypothermia in this high-risk population. The implementation of a protocol with collaboration of a multidisciplinary team is indispensable in providing optimal care to extremely preterm infants.

A Novel Process Audit for Standardized Perioperative Handoff Protocols.

A perioperative handoff protocol provides a standardized delivery of communication during a handoff that occurs from the operating room to the postanestheisa care unit or ICU. The protocol's success is dependent, in part, on its continued proper use over time. A novel process audit was developed to help ensure that a perioperative handoff protocol is used accurately and appropriately over time. The Audit Observation Form is used for the Audit Phase of the process audit, while the Audit Averages Form is used for the Data Analysis Phase. Employing minimal resources and using quantitative methods, the process audit provides the necessary means to evaluate the proper execution of any perioperative handoff protocol.

Effects of Circuit Leak Development Over Time and Response During Low-Flow Volume and Pressure-Controlled Ventilation.

Study Objective: To study the effects of circuit leak development over time and response during volume and pressure controlled ventilation using low flow in human patient simulator and to examine the minimum fresh gas flow needed to compensate for such a leak. Design/Setting: Prospective study using a patient Simulation Lab at Wayne State University. Measurements: A human patient simulator was endotracheally intubated. The endotracheal tube (ETT) was connected to the Datex-Ohmeda AS/3 Anesthesia machine. The tidal volume was set to 500ml in the volume controlled trial and the pressure to 6cm H2O in the pressure controlled trial. A hole was created in each experiment placed 10 cm after the inspiratory valve. Leaks were simulated from holes using 4 different needle diameters: 25, 21, 18 and 16G. A series of data were collected using fresh gas flow at 4 different flow rates (0.5, 1, 1.5 and 2 liters.min-1). Data was measured at different time points (baseline, 1, 3 and 5 minutes) in the series of simulated leaking breathing circuits. Results: Leak alarms were only detected with 16G hole at 5 minutes in the volume control mode versus leaks at 3 minutes with 16G hole and at 5 minutes with 18G hole in the pressure control mode. Conclusion: When a very low flow of 0.5 L/min is used, volume control is safer than pressure control modes.

STOP-Bang and prediction of difficult airway in obese patients.

STUDY OBJECTIVE: To determine if a high score (≥ 3) on the STOP-Bang screening questionnaire for obstructive sleep apnea (OSA) predicts whether obese patients are at high risk for OSA and increased risk of difficult airway. DESIGN: Prospective, questionnaire-based clinical assessment. SETTING: University-affiliated hospital. PATIENTS: 127 ASA physical status 2 and 3 patients, who were scheduled for elective bariatric surgery. INTERVENTIONS: Patients were allocated to three groups. Group 1 patients had a previous history of OSA, Group 2 patients had no history of OSA but did have a high STOP-Bang score (≥ 3), and Group 3 patients had no history of OSA but did have a low STOP-Bang score (< 3). Groups 2 and 3 only were assessed using the STOP-Bang questionnaire. After induction and intubation of the patient, an anesthesiologist who was blinded to the three study group allocations completed an airway questionnaire on the three study groups. MEASUREMENTS: The frequency of difficult airway, difficult mask ventilation with or without muscle relaxation, poor visualization of the vocal cords, difficulty in blade insertion, and difficult intubation were compared. MAIN RESULTS: The group of patients with high STOP-Bang scores (Group 2) and those patients previously diagnosed with OSA (Group1) showed a higher risk for difficult airway than the patients with low STOP-Bang scores (Group 3; P < 0.001). CONCLUSION: The STOP-Bang score may be used as an effective predictor of difficult airway in obese patients. Obese surgical patients with unknown/undiagnosed OSA status should be evaluated using the STOP-Bang questionnaire score.

Effective low dosage of mepivacaine in ultrasound-guided axillary nerve block: a double-blinded, randomized clinical trial of efficacy in patients undergoing distal upper extremity surgery.

STUDY OBJECTIVE: To evaluate two low-dose volumes (20 mL or 30 mL) of 1.5% mepivacaine solution used for ultrasound-guided axillary blockade for outpatients undergoing distal upper limb surgery. DESIGN: Prospective, double-blinded randomized study. SETTING: Outpatient surgical setting of a university-affiliated hospital. PATIENTS: 64 adult, ASA physical status 1, 2, and 3 patients, aged 28-46 years, scheduled for upper limb surgery. INTERVENTIONS: Patients were randomized to two groups to receive either 20 mL of 1.5% mepivacaine solution (n=31) or 30 mL of 1.5% mepivacaine solution (n=33) for ultrasound-guided axillary plexus blockade. MEASUREMENTS: Block duration, proportion of surgical and functional successful blocks, onset of sensory and motor blockade measured from 0 to 30 minutes following final needle extraction, total amount of preoperative sedative (midazolam), and intraoperative propofol administered were recorded. MAIN RESULTS: Following axillary plexus blockade, neither patient group showed any statistically significant difference in the percentage of functionally successful blockade (30 mL, 100%: 20 mL, 97%; P = 0.48), surgically successful blockade (30 mL, 100%; 20 mL, 94%; P = 0.23), cumulative sensory or motor blockade surgical time, block performance time, preoperative midazolam use, or intraoperative propofol use. CONCLUSION: Low volumes (30 mL or 20 mL) of 1.5% mepivacaine provides satisfactory anesthesia for ambulatory distal upper limb surgery with no significant difference in clinical outcomes.

Nicotinic acetylcholine receptor gene expression is altered in burn patients.

INTRODUCTION: Burn patients have been observed to be more susceptible to the hyperkalemic effect of the depolarizing muscle relaxant succinylcholine. Changes in nicotinic acetylcholine receptor (nAChR) subunit composition may alter electrophysiologic, pharmacologic, and metabolic characteristics of the receptor inducing hyperkalemia on exposure to succinylcholine. No studies have been performed that show the upregulation and/or alteration of nAChR subunit composition in human burn patients. The scarcity of studies performed on humans with burn injury is mainly attributable to the technical and ethical difficulties in obtaining muscle biopsies at different time frames of illness in these acutely injured patients. nAChRs are expressed in oral keratinocytes and are upregulated or altered in smokers. However, no studies have addressed the expression of nAChRs in the oral mucosa of burn patients. METHODS: Buccal mucosal scrapings were collected from 9 burn patients and 6 control nonburn surgical intensive care unit patients. For burn and control patients, tissues were collected upon presentation (time: 0 hour) and at time points 12, 24, and 48 hours, 1 week, and 2 weeks. Gene expression of the nAChR subunits alpha1, alpha7, gamma, and epsilon were performed using real-time reverse transcriptase polymerase chain reaction. RESULTS: alpha7 and gamma nAChR genes were significantly upregulated in burn patients, whereas alpha1 and epsilon nAChR genes were minimally affected, showing no significant changes over time. DISCUSSION: Over the 2 weeks of measurement, an upregulation of the alpha7 and gamma genes occurred in both burn and control patients; however, the proportion of alpha7 and gamma subunit increases was significantly higher in burn patients than in control surgical intensive care unit patients. The relationship between the thermal injury and the observed alteration in gene expression suggests a possible cause/effect relationship. This effect was observed at a site not affected by the burn injury and in nonmuscle tissues, thus emphasizing the systemic nature of the effect caused by the thermal injury. Because gene expression is the basis of protein production, the upregulation of alpha7 and gamma genes might translate into more alpha7 and gamma protein subunits. These proteins can also combine with each other or with other types of subunits (alpha1, beta, epsilon . . .) to form nAChRs with altered electrophysiologic characteristics leading to the observed abnormal clinical outcomes. CONCLUSION: Thermal injury may infer a systemic effect because upregulation/alteration of nAChRs occurs in nonmuscle tissues distant from the site of injury. The effect of thermal injury on nAChR gene subunits can be studied using a minimally invasive method (buccal mucosal scraping) and a highly sensitive technology (real-time reverse transcriptase polymerase chain reaction) obviating the need for more invasive methods.