An update on the prone position: Continuing Professional Development

Agreement between non-invasive and invasive arterial blood pressure during surgery in the prone position: an error grid analysis

PURPOSE

Prone position has recently gained renewed importance as a treatment for acute respiratory distress syndrome and spine and brain surgeries. Our study aimed to perform an error grid analysis to examine the clinical discrepancies between arterial blood pressure (ABP) and non-invasive blood pressure (NIBP) in the prone position and to investigate the risk factors influencing these differences.

METHODS

Error grid analysis was performed retrospectively on 1389 pairs of 100 consecutive prone positioning cases. This analysis classifies the difference between the two methods into five clinically relevant zones, from "no risk" to "dangerous risk". Additionally, multivariable ordinal logistic regression analysis was conducted to evaluate the relationship between the risk zones of mean blood pressure (MBP), as classified by error grid analysis and the covariate of interest.

RESULTS

Error grid analysis showed that the proportions of measurement pairs in risk zones A-E for systolic blood pressure were 96.8%, 3.2%, 0.1%, 0%, and 0%, respectively. In contrast, the MBP proportions were 74.0%, 25.1%, 0.9%, 0.1%, and 0%. Multivariable ordinal logistic regression analysis revealed that the position of arms (next to the head) was a significant factor (adjusted odds ratio: 4.35, 95% CI: 2.38-8.33, P < 0.001).

CONCLUSION

Error grid analysis revealed a clinically unacceptable discrepancy between ABP and NIBP for MBP during prone positioning surgery. The position of the arms next to the head was associated with increased clinical discrepancy between the two MBP measurement methods.

Comparison of volume-controlled ventilation, pressure-controlled ventilation and pressure-controlled ventilation-volume guaranteed in infants and young children in the prone position: A prospective randomized study

STUDY OBJECTIVE

To explore if the pressure-controlled ventilation (PCV) and pressure-controlled ventilation-volume guaranteed (PCV-VG) modes are superior to volume-controlled ventilation (VCV) in optimizing intraoperative respiratory mechanics in infants and young children in the prone position.

DESIGN

A single-center prospective randomized study.

SETTING

Children's Hospital, Zhejiang University School of Medicine.

PATIENTS

Pediatric patients aged 1 month to 3 years undergoing elective spinal cord detethering surgery.

INTERVENTIONS

Patients were randomly allocated to the VCV group, PCV group and PCV-VG group. The target tidal volume (VT) was 8 mL/kg and the respiratory rate (RR) was adjusted to maintain a constant end tidal CO2.

MEASUREMENTS

The primary outcome was intraoperative peak airway pressure (Ppeak). Secondary outcomes included other respiratory and ventilation variables, gas exchange values, serum lung injury biomarkers concentration, hemodynamic parameters and postoperative respiratory complications.

MAIN RESULTS

A total of 120 patients were included in the final analysis (40 in each group). The VCV group showed higher Ppeak at T2 (10 min after prone positioning) and T3 (30 min after prone positioning) than the PCV and PCV-VG groups (T2: P = 0.015 and P = 0.002, respectively; T3: P = 0.007 and P = 0.009, respectively). The prone-related decrease in dynamic compliance was prevented by PCV and PCV-VG ventilation modalities at T2 and T3 than by VCV (T2: P = 0.008 and P = 0.015, respectively; T3: P = 0.015 and P = 0.014, respectively). Additionally, there were no significant differences in other secondary outcomes among the three groups.

CONCLUSION

In infants and young children undergoing spinal cord detethering surgery in the prone position, PCV-VG may be a better ventilation mode due to its ability to mitigate the increase in Ppeak and decrease in Cdyn while maintaining consistent VT.

Profound hypoxemia and hypotension during posterior spinal fusion in a spinal muscular atrophy child with severe scoliosis: a case report

BACKGROUND

Anesthesia for spinal muscular atrophy (SMA) patients undergoing spinal deformity surgery is challenging. We report an unusual case of an SMA girl who developed severe intraoperative hypoxemia and hypotension during posterior spinal fusion related with surgical positioning.

CASE PRESENTATION

A 13-yr-old girl diagnosed with SMA type 2, severe kyphoscoliosis and thoracic deformity was scheduled for elective posterior spinal fusion. She developed severe hypoxemia and profound hypotension intraoperatively in the prone position with surgical table tilted 45° to the right. Though transesophageal echocardiography (TEE) could not be performed due to limited mouth opening, her preoperative computed tomography revealed a severely distorted thoracic cavity with much reduced volume of the right side. A reasonable explanation was when the surgeons performed surgical procedure with the tilted surgical table, the pressure was directly put on the shortest diameter of the significantly deformed thoracic cavity, causing severe compression of the pulmonary artery, resulting in both hypoxemia and hypotension. The patient stabilized when the surgical table was tilted back and successfully went through the surgery in the leveled prone position.

CONCLUSIONS

Spinal fusion surgery is beneficial for SMA patients in preventing scoliosis progression and improving ventilation. However, severe scoliosis and thoracic deformities put them at risk of both hemodynamic and respiratory instability during surgical positioning. When advanced monitoring like TEE is not practical intraoperatively, preoperative imaging may help with differential diagnosis, and guide the surgical positioning to minimize mechanical compression of the thoracic cavity, thereby helping the patient complete the surgery safely.

Evaluating the Effects of a General Anesthesia and Prone Position Nursing Checklist and Training Course on Posterior Lumbar Surgery: A Randomized Controlled Trial

BACKGROUND

While general anesthesia in the prone position is one of the most utilized surgical positions, it predisposes to multiple types of complications. Existing studies on this topic are mostly literature reviews or focus on solving one complication, which limits their clinical use.

OBJECTIVE

The aims of the study were to evaluate the effectiveness of a 22-item general anesthesia and prone position nursing checklist and specific training course at preventing complications related to general anesthesia in the prone position.

DESIGN

The study used a randomized controlled trial.

SETTINGS AND PARTICIPANTS

Convenience sampling was used to recruit patients who underwent general anesthesia during posterior lumbar surgery from July 2021 to December 2021 at the Run Run Shaw Hospital, Zhejiang University School of Medicine Hospital.

METHODS

Patients involved in the study were randomly assigned to the control (standard general anesthesia and prone position care) or experimental group (general anesthesia and prone position nursing checklist combined with specific training course in addition to standard general anesthesia and prone position care). Outcomes were pressure injuries, peripheral nerve injuries, ocular complications, and length of stay (LOS). Patient satisfaction, Numeric Pain Rating Scale (NRS) and the Oswestry Disability Scale were also measured.

RESULTS

Compared with the control group, pressure injury, brachial plexus injury, and two ocular findings (foreign body sensation and blurry vision) were significantly less common in the intervention group ( P ≤ 0.01). Participants who received standard general anesthesia and prone position care had lower self-reported satisfaction than those managed with the general anesthesia and prone position nursing checklist plus specific training course ( P = 0.002). The checklist-based intervention also significantly reduced LOS ( P = 0.000) and NRS ( P = 0.000).

CONCLUSIONS

The intervention group had significant fewer general anesthesia in the prone position-related complications, improved satisfaction, reduced LOS, and lower NRS. These findings suggest that a general anesthesia and prone position nursing checklist in addition to a specific training course are beneficial to standardizing prone position nursing care during posterior lumbar surgery.

Midlateral Approach Replantation of a Distal Phalanx Second Toe Amputation in a 4-Year-Old Child: A Case Report

CASE

A 4-year-old girl patient presented with complete amputation of the second toe close to the distal interphalangeal joint. Replantation was performed using a novel midlateral approach. The procedure used the dorsal subcutaneous vein on the foot as a graft for the artery. Four months postoperatively, the toe healed without any complication. The patient reported pain-free physical exercise without limitations in daily activity.

CONCLUSION

This report demonstrates that this approach has the potential to provide a safe and viable alternative for treating toe amputations and offers advantages such as simplified artery identification, straightforward anastomosis, and improved vein graft harvesting.

Safety of prone emergence from general endotracheal anesthesia in patients undergoing ERCP: a randomized controlled trial

BACKGROUND

Conventional supine emergence and prone extubation from general endotracheal anesthesia (GEA) are associated with extubation-related adverse events (ERAEs). Given the minimally invasive nature of endoscopic retrograde cholangiopancreatography (ERCP) as well as the improved ventilation/perfusion matching and easier airway opening in the prone position, we aimed to assess the safety of prone emergence and extubation in patients undergoing ERCP under GEA.

METHODS

Totally, 242 eligible patients were recruited and randomized into the supine extubation group (n = 121; supine group) and the prone extubation group (n = 121; prone group). The primary endpoint was the incidence of ERAEs during emergence, including hemodynamic fluctuations, coughing, stridor, and hypoxemia requiring airway maneuvers. The secondary endpoints included the incidence of monitoring disconnections, extubation time, recovery time, room exit time, and post-procedure sore throat.

RESULTS

The incidence of ERAEs was significantly lower in the prone group compared with the supine group (8.3% vs 34.7%, OR = 0.17, 95% CI 0.18-0.56; P < 0.001). Moreover, the prone group demonstrated no monitoring disconnections, shorter extubation time and room exit time, faster recovery, and, lower frequency and milder sore throat after the procedure.

CONCLUSIONS

For patients undergoing ERCP under GEA, compared with supine, prone emergence, and extubation had remarkably lower rates of EAREs and better recovery, and can maintain continuous monitoring and improve efficiency.

The spine intra-abdominal pressure (SIAP) trial. A prospective, observational, single arm, monocenter study looking at the evolutions of the IAP prior, during and after spine surgery

BACKGROUND AND AIMS

Both anaesthesiologists and spine surgeons consider the intra-abdominal pressure (IAP) as an important peri-operative factor affected by patient positioning. We assessed the change in IAP caused by using a thoraco pelvic support (inflatable prone support, IPS) with the subject under general anesthesia. The IAP was measured before, during and immediately after surgery.

METHODS

The Spine Intra-Abdominal Pressure study (SIAP trial) is a prospective, single-arm, monocenter, observational study looking at changes in IAP prior, during and after spine surgery. The objective is to assess the change in IAP, measured via an indwelling urinary catheter, using the inflatable prone support (IPS) device during prone positioning of patients in spinal surgery.

RESULTS

Forty (40) subjects requiring elective lumbar spine surgery in prone position were enrolled after providing informed consent. The inflation of the IPS results in a significant decrease of IAP (from a median of 9.2 mmHg to 6.46 mmHg (p < 0.001)) in patients undergoing spine surgery in prone position. This decrease in IAP was maintained throughout the procedure despite the discontinuation of muscle relaxants. No serious adverse events or unexpected adverse events occurred.

CONCLUSION

The use of the thoraco-pelvic support IPS device was able to significantly lower the IAP during spine surgery.

Performance of a new auxiliary device based on wrist brace to improve accuracy and feasibility in neuromuscular monitoring with acceleromyography in prone-positioned patients undergoing lumbar spine surgery: a prospective randomized clinical trial

Accuracy of acceleromyography (AMG) is not be comparable to that of mechanomyography or electromyography (EMG). In particular, the prone position may reduce the accuracy and feasibility of AMG. We developed a new device based on wrist brace to allow free thumb movement and fix the other parts of the hand and wrist. We aimed to test whether the brace applied to the AMG would increase precision of AMG and agreement with the EMG in the prone position. Fifty-seven patients, undergoing lumbar surgery under general anesthesia, were randomly assigned to groups to which AMG was applied with or without (no) brace (29 in group B vs. 28 in group NB). EMG was performed in the contralateral arm. Repeatability coefficients of the first twitch height (T1) and train-of-four (TOF) ratio were assessed from nine consecutive measurements during spontaneous recovery from rocuronium-induced neuromuscular block and the AMGs of the two groups were compared in prone position. The agreement between AMG and EMG in each group was assessed using the Bland-Altman method. In group B, the repeatability coefficient of T1 was significantly lower during the recovery to T1 of 25% and TOF ratio of 0.9 (P = 0.017 and 0.033, respectively), indicating higher precision. The mean differences of bias (95% limits of agreement) between AMG and EMG in TOF ratio of 0.9 were 6.839 (- 26.54 to 40.22) in group NB and 3.922 (- 21.83 to 29.67) in group B. The wide limits of agreement in group NB was slightly narrowed in group B but without significance. Trial registration: registered on the UMIN Clinical Trials Registry in August 2020 (UMIN000041310).

Comparison of parameter types for the calibration of noninvasive continuous cardiac output monitoring of patients undergoing lumbar spinal surgery in the prone position

BACKGROUND

Cardiac output (CO) decreases on reversing the patient's position to the prone position. Estimated continuous cardiac output (esCCO) systems can noninvasively and continuously monitor CO calibrated by patient information or transesophageal echocardiogram (TEE).

OBJECTIVE

To compare the accuracy, precision, and trending ability of two calibration methods of CO estimation in patients in prone position.

METHODS

The CO estimates calibrated by TEE (esT) and patient information (esP) of 26 participants were included. CO was collected at four time points. The accuracy and precision of agreement were evaluated using the Bland-Altman method. A four-quadrant plot was used for trending ability analysis.

RESULTS

The bias between esP and TEE and between esT and TEE was 0.2594 L/min (95% limits of agreement (LoA): -1.8374 L/min to 2.3562 L/min) and 0.0337 L/min (95% LoA: -0.7381 L/min to 0.8055 L/min), respectively. A strong correlation was found between ΔesP and ΔTEE (p< 0.001, CCC = 0.700) and between ΔesT and ΔTEE (p< 0.001, CCC = 0.794). The concordance rates between ΔesP and ΔTEE and between ΔesT and ΔTEE were 91.9% and 97.1%, respectively.

CONCLUSION

Despite limited accuracy and precision, esP showed acceptable trending ability. The trending ability of esCCO calibrated by the reference TEE value was comparable with that of TEE.

Dexmedetomidine Combined with Low-Dose Norepinephrine Continuous Pumping to Prevent Hypotension after Cesaresan Section: A Randomized Controlled Trial

Objective

The aim of the study is to explore the clinical effect of dexmedetomidine combined with low-dose norepinephrine (NE) continuous pumping in preventing supine hypotension.

Methods

A total of 160 puerperaes who underwent elective cesarean section were selected. The puerperaes were equally divided into S group (saline), D group (dexmedetomidine), N group (norepinephrine), and DN group (dexmedetomidine combined with norepinephrine) by a random number table method. Apgar scores and umbilical cord venous blood gas values were recorded at 1 and 5 minutes.

Results

There were no statistically significant differences in the age, gestational age, body mass index, bleeding volume, fluid supplement volume, Apgar scores of new borns at the 1st and 5th minute, the blood gas values of umbilical cord arterial and venous in the four groups (P > 0.05). Compared with the S group, the incidence of supine hypotension, the number of NE supplements, the supplementary doses of NE, and the incidence of adverse reactions were significantly reduced in the D, N, and DN groups after spinal anesthesia (P < 0.05). Compared with group D, the incidence of supine hypotension, the number of additional NE, additional dose of NE, and the incidence of adverse reactions in the DN group after spinal anesthesia were significantly reduced (P < 0.05). Compared with the N group, the incidence of supine hypotension, the number of additional NE, the additional dose of NE, and the incidence of adverse reactions in the DN group after spinal anesthesia were significantly reduced (P < 0.05).

Conclusion

Dexmedetomidine combined with continuous pumping of low-dose norepinephrine can effectively prevent the occurrence of supine hypotension, reduce the occurrence of other adverse reactions, and have no obvious adverse effects on neonates. Registration. Chinese Clinical Trial Registry (https://www.chictr.org.cn/enIndex.aspx; ChiCTR2000040979).

Novel use of transesophageal echocardiography to optimize hemodynamics and patient positioning during prone scoliosis surgery and safety considerations in the setting of intraoperative neuromonitoring: a case report

PURPOSE

The prone position can lead to anatomical compression of the thoracic cavity resulting in reduced cardiac output, especially in the context of chest wall deformities commonly present in patients with scoliosis. There are no protocols for using transesophageal echocardiography (TEE) to optimize prone positioning and for safe use of TEE during cases requiring neuromonitoring.

CLINICAL FEATURES

We present a case of a 23-yr-old male with Cornelia de Lange syndrome undergoing elective posterior spinal fusion for syndromic scoliosis who developed severe refractory hypotension and cardiac arrest in the prone position. After hemodynamic stabilization in the intensive care unit, the patient returned to the operating room on postoperative day 2 for completion of his spinal fusion. Transesophageal echocardiography determined the optimal position of longitudinal bolster placements associated with minimal left ventricular compression in the supine position. The patient was then proned and intraoperative hemodynamics during the second surgery remained stable. Owing to the special considerations of using TEE in the prone position with neuromonitoring, we describe technical aspects to consider to protect the equipment and patient.

CONCLUSION

Patients with compliant chest walls or thoracic deformities are at risk of hemodynamic instability in the prone position. Intraoperative TEE can be used in the supine patient prior to proning to determine optimal longitudinal bolster positioning to minimize cardiac compression. Transesophageal echocardiography used during spine surgery in the prone position with neuromonitoring and motor-evoked potentials requires special considerations for patient safety.

The Impact of Individualized Hemodynamic Management on Intraoperative Fluid Balance and Hemodynamic Interventions during Spine Surgery in the Prone Position: A Prospective Randomized Trial

Background and Objectives: The effect of individualized hemodynamic management on the intraoperative use of fluids and other hemodynamic interventions in patients undergoing spinal surgery in the prone position is controversial. This study aimed to evaluate how the use of individualized hemodynamic management based on extended continuous non-invasive hemodynamic monitoring modifies intraoperative hemodynamic interventions compared to conventional hemodynamic monitoring with intermittent non-invasive blood pressure measurements. Methods: Fifty adult patients (American Society of Anesthesiologists physical status I−III) who underwent spinal procedures in the prone position and were then managed with a restrictive fluid strategy were prospectively randomized into intervention and control groups. In the intervention group, individualized hemodynamic management followed a goal-directed protocol based on continuously non-invasively measured blood pressure, heart rate, cardiac output, systemic vascular resistance, and stroke volume variation. In the control group, patients were monitored using intermittent non-invasive blood pressure monitoring, and the choice of hemodynamic intervention was left to the discretion of the attending anesthesiologist. Results: In the intervention group, more hypotensive episodes (3 (2−4) vs. 1 (0−2), p = 0.0001), higher intraoperative dose of ephedrine (0 (0−10) vs. 0 (0−0) mg, p = 0.0008), and more positive fluid balance (680 (510−937) vs. 270 (196−377) ml, p < 0.0001) were recorded. Intraoperative norepinephrine dose and postoperative outcomes did not differ between the groups. Conclusions: Individualized hemodynamic management based on data from extended non-invasive hemodynamic monitoring significantly modified intraoperative hemodynamic management and was associated with a higher number of hemodynamic interventions and a more positive fluid balance.

Perioperative management of spinal cord injury: the anesthesiologist's point of view

BACKGROUND

Traumatic spinal cord injury (SCI) is one of the most devastating events a person can experience. It may be life-threatening or result in long-term disability. This narrative review aims to delineate a systematic step-wise airways, breathing, circulation and disability (ABCD) approach to perioperative patient management during spinal cord surgery in order to fill some of the gaps in our current knowledge.

METHODS

We performed a comprehensive review of the literature regarding the perioperative management of traumatic spinal injuries from May 15, 2020, to December 13, 2020. We consulted the PubMed and Embase database libraries.

RESULTS

Videolaryngoscopy supplements the armamentarium available for airway management. Optical fiberscope use should be evaluated when intubating awake patients. Respiratory complications are frequent in the acute phase of traumatic spinal injury, with an estimated incidence of 36-83%. Early tracheostomy can be considered for expected difficult weaning from mechanical ventilation. Careful intraoperative management of administered fluids should be pursued to avoid complications from volume overload. Neuromonitoring requires investments in staff training and cooperation, but better outcomes have been obtained in centers where it is routinely applied. The prone position can cause rare but devastating complications, such as ischemic optic neuropathy; thus, the anesthetist should take the utmost care in positioning the patient.

CONCLUSIONS

A one-size fit all approach to spinal surgery patients is not applicable due to patient heterogeneity and the complexity of the procedures involved. The neurologic outcome of spinal surgery can be improved, and the incidence of complications reduced with better knowledge of patient-specific aspects and individualized perioperative management.

A practical guide to patient position and complication management in neurosurgery: a systematic qualitative review

PURPOSE

Adequate patient positioning is of paramount importance in neurosurgery. Complications related to the position are common and make up for more than 16% of the claims towards anaesthesiologists and neurosurgeons. This paper aims to provide the anaesthesiologist with a practical guide to avoid common pitfalls related to the patient positioning process.

METHOD

We performed a systematic review of the medical literature for the identification, screening, and inclusion of articles. The bibliographic search was conducted on June 1st, 2021 by two of the authors. In this review, we included articles indexed by MEDLINE, Cochrane Library, or Google Scholar.

RESULTS

We retrieved a total of 5706 unique papers from our initial search. However, after the initial screening, 5363 papers were removed is not related to our research leaving a total of 343 papers. We examined the full text of all the 343 articles including 68 of them in the final qualitative analysis.

DISCUSSION

In this review we examine the most common neurosurgical positions: supine, sitting, lateral, park-bench, prone, jack-knife, and knee-chest. For each of them, the proper positioning and related complications are described. Particular attention is given to the prevention and management of these complications, providing a practical guide for clinicians.

Modified Lateral Position for Achilles Tendon Surgeries: A Technical Tip

Most Achilles tendon surgeries are performed with the patient in the prone position. Some advocate supine position but the access to the tendon is compromised. We describe an innovative technique wherein the patient is positioned lateral but the surgeon has full access to the Achilles tendon as if the patient were positioned prone. We consider that this technique could be easily reproduced and hence widely adopted.

Checking the integrity of eyes in prone position: A novel application of video laryngoscopes

Perioperative visual loss is a rare but severe complication after surgery in prone position. One of several mechanisms is direct ophthalmic compression. This can be avoided through optimal positioning and padding of the head, but position and integrity of the eyes need to be checked at regular intervals. We describe the use of a conventional video laryngoscope during vascular surgery in prone position as a simple solution for intermittent monitoring of external integrity of the eyes and size of the pupils. This requires no additional material and allows documentation of the findings. Our method might reduce complications and improve patient outcome.

Cannulation of the popliteal vein as an intraoperative emergency access in prone position: A case report

Many surgeries have to be performed in the prone position. Access to central vessels is very limited in this position. This requires forward planning with regard to the placement of a central venous catheter. Emergency situations or unexpected intraoperative events in prone position are challenging, as a conventional central venous access is not possible. We describe the cannulation of the popliteal vein in such a case. We report the case of a patient with severe intracerebral hemorrhage who was transferred to our emergency department where his clinical condition rapidly deteriorated. Due to the surgical approach, a prone position was necessary and preoperative central venous cannulation was not possible. We therefore performed an alternative vascular access in prone position using a ultrasound-guided cannulation of the popliteal vein. The cannulation of the popliteal vein described here can be carried out as a quick and easy feasible alternative in emergency situations in prone position. The ultrasound-guided catheter insertion succeeded without any problems and there was no evidence of a deep vein thrombosis after the intervention.

Effect of Two Regimens of Fluid Administration on Airway Edema in Prone-Position Surgery

Background:

Surgeries in prone position expose a patient to multitude of complications including laryngeal edema which may be related to the volume of fluid administered. Administering larger volumes of fluid intraoperatively may contribute to significant tissue edema, leading many anesthesiologists to practice a restrictive fluid infusion strategy. Although previous studies have compared fluid infusion strategies, changes in airway dimensions leading to airway edema have not been extensively investigated. Here, we compared two fluid infusion regimens in patients undergoing spine surgery in the prone position, and assessed their association with airway edema by means of the cuff leak test (CLT).

Aims:

The aim of this study was to test the hypothesis whether a larger volume of crystalloid administration in spine surgeries performed in prone position would result in greater chances of airway edema, than would a restricted infusion policy, utilizing the CLT.

Materials and Methods:

After ethical committee approval, thirty patients, aged 21–60 years, American Society of Anesthesiologists Status I or II, scheduled for elective spine surgery in the prone position, were selected. Group 1 (restrictive group) received 3 mL.kg ^{− 1}.h ^{− 1}, whereas Group 2 (permissive group) received 5 mL.kg ^{− 1}.h ^{− 1} of crystalloids plus urine output replacement. The airway edema was assessed by CLT which was performed soon after intubation (T1) and before extubation (T2). Cuff leak volume (CLV) was calculated from the difference in tidal volumes before (VT_i) and after cuff deflation (VT_e). Airway edema was evaluated by calculating the differences in the CLV at T1 and T2 (ΔCLV); the more the value of Δ CLV which means greater difference between these two points, the more the decrease in laryngeal lumen, signifying an increased risk of airway edema.

Results:

Decrease in laryngeal lumen was observed in patients who received permissive fluid regimen than that of the restrictive group, signifying more chances of airway edema in the former group. In addition, a poor correlation was found between the duration of anesthesia and development of airway edema in our study group.

Conclusions:

Because surgeries in the prone position are at risk of airway edema, restrictive fluid regimen strategy should be preferred over the liberal one as there are more chances of reduction in laryngeal lumen dimensions with permissive fluid infusions.

Effect of intraoperative neuromuscular blockade on postoperative sore throat and hoarseness in patients undergoing spinal surgery: a prospective observational study

Intraoperative neuromuscular blockade affects the resting tension between the vocal cords. We assessed the effect of neuromuscular blockade on postoperative sore throat and hoarseness following tracheal intubation in patients undergoing lumbar spinal surgery in the prone position. Altogether, 99 patients were included; 50 patients did not receive neuromuscular blockade, and 49 patients received moderate neuromuscular blockade during the maintenance of anesthesia. Neuromuscular blockade was performed depending on the use of intraoperative neurophysiological monitoring. The number of intubation attempts, time to achieve tracheal intubation, and duration of intubation were recorded accordingly. The incidence and severity of postoperative sore throat and hoarseness was assessed at 1, 6, and 24 h after surgery. The overall cumulative incidence of postoperative sore throat (60% vs. 59%, respectively; P = 1.000) and postoperative hoarseness (68% vs. 61%, respectively; P = 0.532) did not differ between the no neuromuscular blockade and moderate neuromuscular blockade. The incidence and severity of postoperative sore throat and hoarseness was also not different between the moderate and no neuromuscular blockade at each time point after surgery. Nevertheless, the incidences of postoperative sore throat and hoarseness were quite high. Further studies investigating strategies to alleviate them are warranted accordingly.

A Comparison of a Standard Macintosh Blade Laryngoscope, Pentax-AWS Videolaryngoscope and Intubrite Videolaryngoscope for Tracheal Intubation in Manikins in Sitting and Prone Positions: A Randomized Cross-Over Study

Background: Intubation of a patient in different positions may be done not only in emergency settings, but also in routine anesthesia (e.g., prone position for lumbar spine surgery). Methods: The aim of the study was to compare the classic Macintosh blade laryngoscope with two videolaryngoscopes: the Pentax-AWS and the Intubrite in a simulated scenario of a manikin placed in a sitting and prone position. Additionally, intubation with the use of all three devices was performed in a standard supine position as the control group. The time of intubation and the pressure exerted on the tongue was assessed. The ANOVA Friedman (analysis of variance) and Wilcoxon with Bonferroni correction tests were used for statistical analysis. Results: The time of intubation in a prone position was significantly shorter for the Pentax-AWS videolaryngoscope compared to the Macintosh and the Intubrite. There were no significant differences in the obtained results of the evaluated devices in sitting and standard positions. The lowest pressure exerted on the tongue was with the Pentax-AWS, followed by the Intubrite and the Macintosh laryngoscopes. Conclusions: The use of the Pentax-AWS was associated with faster tracheal intubation, creating lower pressure on tongue when compared with standard Macintosh and Intubrite laryngoscopes in both prone and sitting positions.

Ultrasound-Guided Neuraxial Anesthesia

PURPOSE OF REVIEW

There has been a recent surge of interest in clinical applications of ultrasound, which has revolutionized acute pain management. This review is to summarize the current status of ultrasound utilization in neuraxial anesthesia, the most common type of regional anesthesia.

RECENT FINDINGS

Ultrasound-assisted and ultrasound-guided neuraxial anesthesia has improved clinical accuracy and patient safety through landmark identification including proper vertebral level and midline, as well as via measurements on neuraxial space. Direct needle or catheter visualization during the entire procedure has not yet been achieved consistently. The recent introduction of ultrasound into neural anesthesia has clinical performance benefits and patient safety implications, with documented improvement on overall efficacy with higher first attempt success rate as well as less needle pass. More controlled studies are needed for the overall impact of ultrasonography in neuraxial anesthesia in obstetric and non-obstetric patients.

Transthoracic Echocardiography in Prone Patients With Acute Respiratory Distress Syndrome: A Feasibility Study

Supplemental Digital Content is available in the text.

Objectives:

Patients with acute respiratory distress syndrome are at risk for developing cardiac dysfunction which is independently associated with worse outcomes. Transthoracic echocardiography is an ideal imaging modality for goal-directed assessment and optimization of cardiac function and volume status. Prone positioning, while demonstrated to improve oxygenation, offload the right ventricle, and reduce short-term mortality in acute respiratory distress syndrome, has previously precluded transthoracic echocardiography on these patients. The purpose of this study was to assess the ability to perform focused transthoracic echocardiography examinations on acute respiratory distress syndrome patients in the prone position.

Design:

We performed a cross-sectional study of critically ill patients hospitalized for acute respiratory distress syndrome due to coronavirus disease 2019.

Setting:

This study was conducted in medical and surgical intensive units in a tertiary hospital.

Patients:

We examined 27 mechanically ventilated and prone patients with acute respiratory distress syndrome due to coronavirus disease 2019. Participants were examined at the time of enrollment in an ongoing clinical trial (NCT04306393), and no patients were excluded from echocardiographic analysis.

Interventions:

None.

Measurements and Main Results:

We were able to perform transthoracic echocardiography and obtain satisfactory images for quantitative assessment of right ventricular function in 24 out of 27 (88.9%) and left ventricular function in 26 out of 27 (96.3%) of patients in the prone position, including many who were obese and on high levels of positive end-expiratory pressure (≥ 15 cm H₂O).

Conclusions:

Transthoracic echocardiography can be performed at the prone patient’s bedside by critical care intensivists. These findings encourage the use of focused transthoracic echocardiography for goal-directed cardiac assessment in acute respiratory distress syndrome patients undergoing prone positioning.

Incidence of Pressure-Related Skin Injuries in Patients Operated for Spine Surgery in Prone: A Retrospective Analysis of 307 Patients

Background:

Spine surgery in prone position frequently results in pressure skin lesions (PSLs). No study from Arabic world has published their incidence in literature.

Methods:

We retrospectively analyzed patients who underwent prone position spine surgery from December 1, 2017, to November 30, 2018. They received standardized anesthesia care and were made prone on Jackson table. The face was supported on a nonface contoured foam device, whereas the chest and pelvis were supported on soft cushions. Following completion of surgery, they were turned supine and their skin was inspected for any skin lesions. The lesions were categorized into five grades depending on severity.

Results:

Data of 307 patients were analyzed. Their mean age and weight was 41.5 years and 71 kg, respectively. The mean duration of prone positioning was 470 min. One hundred and three PSLs were observed in 45 patients (14.7%), giving a PSL incidence of 43.7% in affected patients. Majority of patients (18, 40%) with lesions remained in prone position between 421 and 600 min. Multiple lesions were observed in 53.3% of the affected patients. The highest number of patients (21, 46.7%) had one lesion only and it was restricted to face. All lesions were of Grade I, II, or III. Body weight >71 kg was more prone to developing PSLs. Females were more prone to PSLs.

Conclusion:

PSLs in prone position spine surgery occur frequently, and their incidence is proportional to the duration of positioning and weight of the patients. Face is the most commonly affected area.

Anesthetic management of complex spine surgery in adult patients: a review based on outcome evidence

PURPOSE OF REVIEW

The aim of this article is to review the evidence regarding the anesthetic management of blood loss, pain control, and position-related complications of adult patients undergoing complex spine procedures.

RECENT FINDINGS

The most recent evidence of the anesthetic management of complex spine surgery was identified with a systematic search and graded. In our review, prophylactic tranexamic acid and optimal prone positioning were shown to be effective blood conservation strategies with minimal risks to the patients. Cell saver was cost-effective in complex surgeries with expected blood loss of greater than 500 ml. As for pain control, most interventions only produced mild analgesic effects, suggesting a multimodal approach is necessary to achieve optimal pain control after spine surgery. Regional techniques and NSAIDs were effective but because of their risks, their usage should be discussed with the surgical team. Further studies are required to assess the effectiveness, cost-effectiveness, and risks associated with combined uses of different analgesic interventions. On the basis of the available evidence, we recommend a combined use of gabapentinoids, ketamine, and opioids to achieve optimal analgesia. Lastly, literature for position-related injuries is heavily relied on case reports and the Anesthesia Closed Claim Study because of their rarity. Therefore, we advocate for a structured team-based approach with checklists to minimize position-related complications.

SUMMARY

As the number and complexity of spine procedures are being performed worldwide is increasing, we suggested to bundle the aforementioned effective interventions as part of an ERAS spine protocol to improve the patient outcome of spine surgery.

Effect of Hemodynamic Changes in Plasma Propofol Concentrations Associated with Knee-Chest Position in Spinal Surgery: A Prospective Study

Background

Anesthesia induction and maintenance with propofol can be guided by target-controlled infusion (TCI) systems using pharmacokinetic (Pk) models. Physiological variables, such as changes in cardiac output (CO), can influence propofol pharmacokinetics. Knee-chest (KC) surgical positioning can result in CO changes.

Objectives

This study aimed to evaluate the relationship between propofol plasma concentration prediction and CO changes after induction and KC positioning.

Methods

This two-phase prospective cohort study included 20 patients scheduled for spinal surgery. Two different TCI anesthesia protocols were administered after induction. In phase I (n = 9), the loss of consciousness (LOC) concentration was set as the propofol target concentration and CO changes following induction and KC positioning were quantified. In phase II (n = 11), based on data from phase I, two reductions in the propofol target concentration on the pump were applied after LOC and before KC positioning. Propofol plasma concentrations were measured at different moments in both phases: after induction and after KC positioning.

Results

Schnider Pk model showed a good performance in predicting propofol concentration after induction; however, after KC positioning, when a significant drop in CO occurred, the measured propofol concentrations were markedly underestimated. Intended reductions in the propofol target concentration did not attenuate HD changes. In the KC position, there was no correlation between the propofol concentration estimated by the Pk model and the measured concentration in plasma, as the latter was much higher (P = 0.013) while CO and BIS decreased significantly (P < 0.001 and P = 0.004, respectively).

Conclusions

Our study showed that the measured propofol plasma concentrations during the KC position were significantly underestimated by the Schnider Pk model and were associated with significant CO decrease. When placing patients in the KC position, anesthesiologists must be aware of pharmacokinetic changes and, in addition to standard monitoring, the use of depth of anesthesia and cardiac output monitors may be considered in high-risk patients.

Anesthetic considerations in spine surgery: What orthopaedic surgeon should know!

With clinical innovation and technological advancement, the paradigm of surgical procedures on the spine and spinal cord along with the perioperative management are rapidly evolving. Irrespective of different modes the anesthetic management of spine surgery is challenging in view of significant blood loss, prolong procedure, position-related complications, and complex pain management. The enhanced recovery after surgery (ERAS) for this kind of surgery is yet to be finalized. The aim of this article is to highlight the current evidence-based major perioperative considerations for patients undergoing spine surgery.

Intraoperative Kirschner Wire Migration during Robotic Minimally Invasive Spine Surgery

We present the case of a 58-year-old woman who underwent a minimally invasive robotic-assisted L4-S1 instrumentation and fusion which was complicated by a Kirschner wire (K-wire) fracture and migration into the abdominal cavity necessitating emergent exploratory laparotomy. Retrieval of the K-wire proceeded without incident, and the patient had an otherwise uneventful surgery and recovery. This is the first such case description reported in the literature. As minimally invasive robotic-assisted spine procedures become more common, it is essential for the anesthesiologist to be familiar with potential complications to manage such patients in the perioperative period optimally.

Comparison of volume-controlled ventilation mode and pressure-controlled ventilation with volume-guaranteed mode in the prone position during lumbar spine surgery

Background

During lumbar spine surgery, patients are placed in the prone position for surgical access. The prone position has various effects on cardiac and pulmonary function, including a decreased cardiac index (CI), decreased dynamic lung compliance (Cdyn), and increased peak inspiratory pressure (Ppeak). In this study, we compared the volume-controlled ventilation mode (VCV) and pressure-controlled ventilation with volume guaranteed mode (PCV-VG) based on hemodynamic and pulmonary variables in the prone position during lumbar spine surgery.

Methods

Thirty-six patients scheduled for lumbar spine surgery in the prone position were enrolled in this prospective, randomized clinical trial. The patients were randomly assigned to receive VCV or PCV-VG. Hemodynamic variables, respiratory variables, and arterial blood gases were measured in the supine position 15 min after the induction of anesthesia, 15 min after placement in the prone position, 30 min after placement in the prone position, and 15 min after placement in the supine position at the end of anesthesia.

Results

The hemodynamic variables and arterial blood gas results did not differ significantly between the two groups. Lower Ppeak values were observed in the PCV-VG group than in the VCV group (p = 0.045). The Cdyn values in the VCV group were lower than those in the PCV-VG group (p = 0.040).

Conclusion

PCV-VG led to lower Ppeak and improved Cdyn values compared with VCV, showing that it may be a favorable alternative mode of mechanical ventilation for patients in the prone position during lumbar spine surgery.

Trial registration

The study was retrospectively registered at ClinicalTrials.gov (NCT 03571854). The initial registration date was 6/18/2018.

The significance of intra-abdominal pressure in neurosurgery and neurological diseases: a narrative review and a conceptual proposal

Intra-abdominal pressure (IAP) is a physiological parameter that has gained considerable attention during the last few decades. The incidence of complications arising from increased IAP, known as intra-abdominal hypertension (IAH) or abdominal compartment syndrome in critically ill patients, is high and its impact is significant. The effects of IAP in neurological conditions and during surgical procedures are largely unexplored. IAP also appears to be relevant during neurosurgical procedures (spine and brain) in the prone position, and in selected cases, IAH may affect cerebrospinal fluid drainage after a ventriculoperitoneal shunt operation. Furthermore, raised IAP is one of the contributors to intracranial hypertension in patients with morbid obesity. In traumatic brain injury, case reports described how abdominal decompression lowers intracerebral pressure. The anatomical substrate for transmission of the IAP to the brain and venous system of the spine is the extradural neural axis compartment; the first reports of this phenomenon can be found in anatomical studies of the sixteenth century. In this review, we summarize the available knowledge on how IAP impacts the cerebrospinal venous system and the jugular venous system via two pathways, and we discuss the implications for neurosurgical procedures as well as the relevance of IAH in neurological disorders.

Karydakis procedure can be effectively performed in the lateral position

BACKGROUND

Karydakis published a large pilonidal series in 1992, reporting a recurrence rate of less than 1% and complication rate of 8.5%. The aim of this study was to compare the outcomes of Karydakis procedure (KP) performed in the lateral versus the prone position in a consecutive series.

METHODS

Ninety-seven consecutive patients undergoing a KP between March 2000 and February 2018 were retrospectively assessed. Patients with disease sinuses or fistulas extending from the midline to either left or right sides only were considered for KP in the contralateral side position.

RESULTS

Surgery was carried out for primary pilonidal disease in 71 patients (73%) and for recurrent disease in 26 patients (27%). The majority (62%) of pilonidal tracts veered off from the midline to either the left or right side only. Wound complications, mostly minor skin separation, occurred in 37 patients (38%). Disease recurrence occurred in eight patients (8%). There was no difference between patients who had KP in a lateral position compared with those operated in a prone position regarding wound complications (41% versus 35%, P = 0.675), disease recurrence (9% versus 7%, P = 1.000), mean operating time (64.6 min versus 66.6 min, P = 0.259) and mean length of hospital stay (1 day for both groups).

CONCLUSIONS

Pilonidal surgery in the lateral position has potential benefits for patient safety, patient comfort and theatre efficiency. The clinical results of this series show that the KP can be performed safely and effectively with the patient in the lateral position for most cases of pilonidal disease.

Pulse pressure variation and pleth variability index as predictors of fluid responsiveness in patients undergoing spinal surgery in the prone position

Background

This study investigated the ability of pulse pressure variation (PPV) and pleth variability index (PVI) to predict fluid responsiveness of patients undergoing spinal surgery in the prone position.

Patients and methods

A total of 53 patients undergoing posterior lumbar spinal fusion in the prone position on a Jackson table were studied. PPV, PVI, and hemodynamic and respiratory variables were measured both before and after the administration of 6 mL/kg colloid in both the supine and prone positions. Fluid responsiveness was defined as a 15% or greater increase in stroke volume index, as assessed by esophageal Doppler monitor after fluid loading.

Results

In the supine position, 40 patients were responders. The areas under the receiver operating characteristic (ROC) curves for PPV and PVI were 0.783 [95% CI 0.648–0.884, P<0.001] and 0.814 (95% CI 0.684–0.908, P<0.001), respectively. The optimal cut-off values of PPV and PVI were 10% (sensitivity 75%, specificity 62%) and 8% (sensitivity 78%, specificity 77%), respectively. In the prone position, 27 patients were responders. The areas under the ROC curves for PPV and PVI were 0.781 (95% CI 0.646–0.883, P<0.001) and 0.756 (95% CI 0.618–0.863, P<0.001), respectively. The optimal cut-off values of PPV and PVI were 7% (sensitivity 82%, specificity 62%) and 8% (sensitivity 67%, specificity 69%), respectively.

Conclusion

Both PPV and PVI were able to predict fluid responsiveness; their predictive abilities were maintained in the prone position.

Guideline Implementation: Positioning the Patient

Every surgical procedure requires positioning the patient; however, all surgical positions are associated with the potential for the patient to experience a positioning injury. The locations and types of potential injuries (eg, stretching, compression, pressure injury) depend on the position. Factors that may increase the patient's risk for an injury are the length of the procedure and risk factors inherent to the patient (eg, weight, age, frailty). AORN's updated "Guideline for positioning the patient" provides guidance on injury prevention practices for all surgical positions including supine, Trendelenburg, reverse Trendelenburg, lateral, lithotomy, prone, and sitting positions and modifications of these positions. This article focuses on the key points of the guideline covering the use of prophylactic dressings, neurophysiological monitoring, and safely positioning the patient in the supine and prone positions. Perioperative RNs should review the complete guideline for additional information and for guidance when writing and updating policies and procedures.

A randomized comparison of the prone ventilation endotracheal tube versus the traditional endotracheal tube in adult patients undergoing prone position surgery

Endotracheal tube displacement or dislocation is a severe complication that can occur in patients who require prone position ventilation. We hypothesized the prone position tube (PPT) would reduce the incidence of displacement of an endotracheal tube in an adult prone operation compared to a traditional tube (TT). A total of 80 adult patients undergoing neurosurgery or spine surgery were recruited. Sixty patients with prone position ventilation were randomly divided into the traditional routine endotracheal tube group (Group TT, n = 30) and the prone position ventilation endotracheal tube group (Group PPT, n = 30). The primary outcome measures were the incidence of the endotracheal tube displacement during surgery, and the secondary outcomes were symptoms of sore throat, dysphagia and dysphonia during follow-up in the post-anesthesia care unit (PACU). The incidence of tube displacement was significantly lower in the PPT group (0 [0%] of 30 patients) compared to the TT group (22 [73.3%] of 30 patients; odds ratio [OR] 0.73, 95% CI 0.591-0.910; P = 0.005). There was no statistical difference in sore throat, dysphagia and vocal function between the two groups (P > 0.05) during follow-up. Compared to the traditional tube, the improved prone positon tube reduced the incidence of displacement of the endotracheal tube. This study was registered with ClinicalTrials.gov on April 29, 2015 (No. NCT02449356).