Prone Positioning of Ventilated Patients During Air Medical Evacuation: A Case Series.

OBJECTIVE: The purpose of this study was to investigate patient safety implications of transporting prone-positioned mechanically ventilated patients in the air medical environment (AME). METHODS: A retrospective health record review of patient encounters from 2019 to 2021 was conducted using British Columbia Emergency Health Services air medical electronic patient care reports. RESULTS: A total of 633 patients were identified as intubated, mechanically ventilated, and transported by British Columbia Emergency Health Services air medical teams. Ten patients were identified as having been transported in the prone position. Oxygen saturation, arterial blood oxygen levels, and carbon dioxide measurements from 8 cases indicated that patients remained stable or improved during transport. Cardiovascular episodes including hypotension and tachycardia were observed. In 2 patients, a mean 17.5% decline in oxygen saturation was identified. It could not be determined if this was a result of prone positioning during AME or due to a deteriorating physiological condition related to the patient's underlying disease. There were no identified tube dislodgments during AME transport. CONCLUSION: Although proning did not compromise patient safety with respect to tube or line displacement in our study, we cannot draw definitive conclusions regarding the safety implications of proning on patient vital signs during transport.

The effect of prone positioning on maternal haemodynamics and fetal wellbeing in the third trimester-A primary cohort study with a scoping review.

INTRODUCTION: Supine sleep position is associated with stillbirth, likely secondary to inferior vena cava compression, and a reduction in cardiac output (CO) and uteroplacental perfusion. Evidence for the effects of prone position in pregnancy is less clear. This study aimed to determine the effect maternal prone position on maternal haemodynamics and fetal heart rate, compared with left lateral position. METHODS: Twenty-one women >28 weeks' gestation underwent non-invasive CO monitoring (Cheetah) every 5 minutes and continuous fetal heart rate monitoring (MONICA) in left lateral (20 minutes), prone (30 minutes), followed by left lateral (20 minutes). Anxiety and comfort were assessed by questionnaires. Regression analyses (adjusted for time) compared variables between positions. The information derived from the primary study was used in an existing mathematical model of maternal circulation in pregnancy, to determine whether occlusion of the inferior vena cava could account for the observed effects. In addition, a scoping review was performed to identify reported clinical, haemodynamic and fetal effects of maternal prone position; studies were included if they reported clinical outcomes or effects or maternal prone position in pregnancy. Study records were grouped by publication type for ease of data synthesis and critical analysis. Meta-analysis was performed where there were sufficient studies. RESULTS: Maternal blood pressure (BP) and total vascular resistance (TVR) were increased in prone (sBP 109 vs 104 mmHg, p = 0.03; dBP 74 vs 67 mmHg, p = 0.003; TVR 1302 vs 1075 dyne.s-1cm-5, p = 0.03). CO was reduced in prone (5.7 vs 7.1 mL/minute, p = 0.003). Fetal heart rate, variability and decelerations were unaltered. However, fetal accelerations were less common in prone position (86% vs 95%, p = 0.03). Anxiety was reduced after the procedure, compared to beforehand (p = 0.002), despite a marginal decline in comfort (p = 0.04).The model predicted that if occlusion of the inferior vena cava occurred, the sBP, dBP and CO would generally decrease. However, the TVR remained relatively consistent, which implies that the MAP and CO decrease at a similar rate when occlusion occurs. The scoping review found that maternal and fetal outcomes from 47 included case reports of prone positioning during pregnancy were generally favourable. Meta-analysis of three prospective studies investigating maternal haemodynamic effects of prone position found an increase in sBP and maternal heart rate, but no effect on respiratory rate, oxygen saturation or baseline fetal heart rate (though there was significant heterogeneity between studies). CONCLUSION: Prone position was associated with a reduction in CO but an uncertain effect on fetal wellbeing. The decline in CO may be due to caval compression, as supported by the computational model. Further work is needed to optimise the safety of prone positioning in pregnancy. TRIAL REGISTRATION: This trial was registered at clinicaltrials.gov (NCT04586283).

Factors associated with a nonresponse to prone positioning in patients with severe acute respiratory distress syndrome due to SARS-CoV-2.

OBJECTIVE: To identify risk factors for nonresponse to prone positioning in mechanically ventilated patients with COVID-19-associated severe acute respiratory distress syndrome and refractory hypoxemia in a tertiary care hospital in Colombia. METHODS: Observational study based on a retrospective cohort of mechanically ventilated patients with severe acute respiratory distress syndrome due to SARS-CoV-2 who underwent prone positioning due to refractory hypoxemia. The study considered an improvement ≥ 20% in the PaO2/FiO2 ratio after the first cycle of 16 hours in the prone position to be a 'response'. Nonresponding patients were considered cases, and responding patients were controls. We controlled for clinical, laboratory, and radiological variables. RESULTS: A total of 724 patients were included (58.67 ± 12.37 years, 67.7% males). Of those, 21.9% were nonresponders. Mortality was 54.1% for nonresponders and 31.3% for responders (p < 0.001). Variables associated with nonresponse were time from the start of mechanical ventilation to pronation (OR 1.23; 95%CI 1.10 - 1.41); preintubation PaO2/FiO2 ratio (OR 0.62; 95%CI 0.40 - 0.96); preprone PaO2/FiO2 ratio (OR 1.88. 95%CI 1.22 - 2.94); and radiologic multilobe consolidation (OR 2.12; 95%CI 1.33 - 3.33) or mixed pattern (OR 1.72; 95%CI 1.07 - 2.85) compared with a ground-glass pattern. CONCLUSION: This study identified factors associated with nonresponse to prone positioning in patients with refractory hypoxemia and acute respiratory distress syndrome due to SARS-CoV-2 receiving mechanical ventilation. Recognizing such factors helps identify candidates for other rescue strategies, including more extensive prone positioning or extracorporeal membrane oxygenation. Further studies are needed to assess the consistency of these findings in populations with acute respiratory distress syndrome of other etiologies.

Effect of Awake Prone Positioning on ROX Index in Critically-ill Patients With Respiratory Failure due to COVID-19.

COVID-19 pneumonia causes acute respiratory distress syndrome (ARDS). Prone positioning (PP) is beneficial to pulmonary physiology and improves oxygenation in patients with ARDS. We aimed to investigate the effect of the PP on oxygenation, respiratory rate (RR) and ROX index in non-intubated patients with COVID-19 associated respiratory failure and to determine whether ROX index predicts intubation. Awake critically-ill patients with confirmed diagnosis of COVID-19 who underwent PP were enrolled in the retrospective, single-center study. Oxygenation parameters were recorded 1 h before PP, during PP and 1 h after return to supine position (after PP). Intubation was defined as the endpoint. Seventy-one patients with a median age of 64 [55-73] years were enrolled in the study. PaO2/FiO2 and SpO2/FiO2 improved during PP, this improvement did not persist after PP. RR improved during and after PP in both intubated and non-intubated patients (for all P < .001). ROX index improved only in non-intubated patients (P < .001) but not in intubated patients (P = .07). Area under the curve (AUC) of ROX index for intubation before PP, during PP and after PP were 0.74 [0.61-0.88] (P = .002), 0.76 [0.62-0.91] (P = .001), and 0.76 [0.64-0.89] (P = .001), respectively. ROX index >6.83 before PP had a negative predictive value (NPV) of 0.85; ROX index >8.28 during PP had a NPV of 0.88 and ROX index >7.48 after PP had a NPV of 0.85. In logistic regression adjusted for APACHE II score, ROX index ≤6.83 before PP had an odds ratio (OR) 4.47 [1.39-14.38], ROX index ≤8.28 during PP had an OR 7.96 [2.29-27.64] and ROX index ≤7.48 had an OR 3.98 [1.25-12.61] for prediction of intubation. In conclusion, awake PP improves oxygenation and decreases RR. ROX index improved only in non- intubated patients and a higher ROX index predicts lower risk of progressing to mechanical ventilation with intubation.

Awake prone positioning in acute hypoxaemic respiratory failure.

Awake prone positioning (APP) of patients with acute hypoxaemic respiratory failure gained considerable attention during the early phases of the coronavirus disease 2019 (COVID-19) pandemic. Prior to the pandemic, reports of APP were limited to case series in patients with influenza and in immunocompromised patients, with encouraging results in terms of tolerance and oxygenation improvement. Prone positioning of awake patients with acute hypoxaemic respiratory failure appears to result in many of the same physiological changes improving oxygenation seen in invasively ventilated patients with moderate-severe acute respiratory distress syndrome. A number of randomised controlled studies published on patients with varying severity of COVID-19 have reported apparently contrasting outcomes. However, there is consistent evidence that more hypoxaemic patients requiring advanced respiratory support, who are managed in higher care environments and who can be prone for several hours, benefit most from APP use. We review the physiological basis by which prone positioning results in changes in lung mechanics and gas exchange and summarise the latest evidence base for APP primarily in COVID-19. We examine the key factors that influence the success of APP, the optimal target populations for APP and the key unknowns that will shape future research.

Association of lung recruitment and change in recruitment-to-inflation ratio from supine to prone position in acute respiratory distress syndrome.

Prone positioning is an evidence-based treatment for patients with moderate-to-severe acute respiratory distress syndrome. Lung recruitment has been proposed as one of the mechanisms by which prone positioning reduces mortality in this group of patients. Recruitment-to-inflation ratio (R/I) is a method to measure potential for lung recruitment induced by a change in positive end-expiratory pressure (PEEP) on the ventilator. The association between R/I and potential for lung recruitment in supine and prone position has not been studied with computed tomography (CT) scan imaging. In this secondary analysis, we sought to investigate the correlation between R/I measured in supine and prone position with CT and the potential for lung recruitment as measured by CT scan. Among 23 patients, the median R/I did not significantly change from supine (1.9 IQR 1.6-2.6) to prone position (1.7 IQR 1.3-2.8) (paired t test p = 0.051) but the individual changes correlated with the different response to PEEP. In supine and in prone position, R/I significantly correlated with the proportion of lung tissue recruitment induced by the change of PEEP. Lung tissue recruitment induced by a change of PEEP from 5 to 15 cmH2O was 16% (IQR 11-24%) in supine and 14.3% (IQR 8.4-22.6%) in prone position, as measured by CT scan analysis (paired t test p = 0.56). In this analysis, PEEP-induced recruitability as measured by R/I correlated with PEEP-induced lung recruitment as measured by CT scan, and could help to readjust PEEP in prone position.

Prone positioning in COVID-19 patients with acute respiratory distress syndrome and invasive mechanical ventilation.

OBJECTIVE: To identify adverse events related to prone positioning in COVID-19 patients with severe disease and acute respiratory distress syndrome, to analyze the risk factors associated with the development of anterior pressure ulcers, to determine whether the recommendation of prone positioning is associated with improved clinical outcomes. METHODS: Retrospective study performed in 63 consecutive patients with COVID-19 pneumonia admitted to intensive care unit on invasive mechanical ventilation and treated with prone positioning between March and April 2020. Association between prone-related pressure ulcers and selected variables was explored by the means of logistic regression. RESULTS: A total of 139 proning cycles were performed. The mean number of cycles were 2 [1-3] and the mean duration per cycle was of 22h [15-24]. The prevalence of adverse events this population was 84.9 %, being the physiologic ones (i.e., hypo/hypertension) the most prevalent. 29 out of 63 patients (46%) developed prone-related pressure ulcers. The risk factors for prone-related pressure ulcers were older age, hypertension, levels of pre-albumin <21mg/dl, the number of proning cycles and severe disease. We observed a significant increase in the PaO2/FiO2 at different time points during the prone positioning, and a significant decrease after it. CONCLUSIONS: There is a high incidence of adverse events due to PD, with the physiological type being the most frequent. The identification of the main risk factors for the development of prone-related pressure ulcers will help to prevent the occurrence of these lesions during the prone positioning. Prone positioning offered an improvement in the oxygenation in these patients.

Aging-related predictive factors for oxygenation improvement and mortality in COVID-19 and acute respiratory distress syndrome (ARDS) patients exposed to prone position: A multicenter cohort study.

BACKGROUND: Elderly patients are more susceptible to Coronavirus Disease-2019 (COVID-19) and are more likely to develop it in severe forms, (e.g., Acute Respiratory Distress Syndrome [ARDS]). Prone positioning is a treatment strategy for severe ARDS; however, its response in the elderly population remains poorly understood. The main objective was to evaluate the predictive response and mortality of elderly patients exposed to prone positioning due to ARDS-COVID-19. METHODS: This retrospective multicenter cohort study involved 223 patients aged ≥ 65 years, who received prone position sessions for severe ARDS due to COVID-19, using invasive mechanical ventilation. The PaO2/FiO2 ratio was used to assess the oxygenation response. The 20-point improvement in PaO2/FiO2 after the first prone session was considered for good response. Data were collected from electronic medical records, including demographic data, laboratory/image exams, complications, comorbidities, SAPS III and SOFA scores, use of anticoagulants and vasopressors, ventilator settings, and respiratory system mechanics. Mortality was defined as deaths that occurred until hospital discharge. RESULTS: Most patients were male, with arterial hypertension and diabetes mellitus as the most prevalent comorbidities. The non-responders group had higher SAPS III and SOFA scores, and a higher incidence of complications. There was no difference in mortality rate. A lower SAPS III score was a predictor of oxygenation response, and the male sex was a risk predictor of mortality. CONCLUSION: The present study suggests the oxygenation response to prone positioning in elderly patients with severe COVID-19-ARDS correlates with the SAPS III score. Furthermore, the male sex is a risk predictor of mortality.

The effect of extubation in prone position on emergence and recovery in lumbar spinal surgery.

BACKGROUND: Extubation of patients in supine position after prone operations may lead to unwanted effects on hemodynamic and respiratory parameters during emergence and recovery period. We aimed to observe the effects of prone position on emergence and recovery periods after prone surgery. METHODS: This randomized controlled trial was studied with sixty patients extubated either in prone position (30 patients) or in supine position (30 patients) after lumbar spinal surgery in tertiary educational hospitals. Heart rate, non-invasive arterial blood pressure, peripheral oxygen saturation and Bispectral Index values were measured, and recorded in all patients during operation, at the time an anesthetic agent was discontinued, before and after extubation. The number of the mouth suctioning, Aldrete recovery score, and Ricker agitation score were recorded together with the severity of cough during emergence and recovery. Incidents such as nausea, vomiting, respiratory failure, uncontrolled airway, and decreased saturation were also recorded. RESULTS: Heart rate and mean arterial pressure values were significantly lower in the prone group during emergence and recovery period compared with the supine group (P<0.05). Aldrete Recovery Scores were higher in the prone group (P<0.001). The number of the mouth suctioning and the cough severity were lower in the prone group (P<0.001). CONCLUSIONS: Extubation in the prone position provides a more comfortable emergence and recovery periods by less altering the hemodynamic and respiratory status with better recovery profile.

Effects of awake-prone positioning on oxygenation and physiological outcomes in non-intubated patients with COVID-19: A randomized controlled trial.

BACKGROUND: Prone positioning is a well-known supportive approach for increasing oxygenation and reducing mortality in non-COVID-19 patients with moderate to severe acute respiratory distress syndrome. However, studies highlighting the effects of proning in patients with COVID-19 are limited. AIM: To investigate the effects of awake-prone positioning (APP) on oxygenation and physiological outcomes in non-intubated patients with COVID-19. STUDY DESIGN: A randomized controlled trial was carried out with two parallel groups at 1:1 ratio. Adult awake non-intubated patients with confirmed COVID-19, non-rebreathing face mask or continuous positive airway pressure, PaO2 /FiO2 ratio ≤150 mmHg were randomly assigned to the APP group or control group. The control group was subjected to conventional positioning interventions. Outcome measures were PaO2 /FiO2 ratio, ROX index, PaO2 , PaCO2 , SaO2 , respiratory rate, blood pressure, and shock index. These parameters were recorded immediately before positioning, 10 min after patient positioning, and 1 h after patient positioning. RESULTS: Of 115 patients assessed for eligibility, 82 were randomized to the APP group or control group (41 patients in each group). The use of APP for non-intubated patients with COVID-19 resulted in statistically significant improvements in oxygenation parameters, that is, SpO2 , PaO2 /FiO2 , ROX index, PaO2 , and SaO2 , at the three study time points (p = .000, .007, .000, .011, and .000 respectively). The SpO2 was increased to 92.15 ± 2.735 mmHg for the APP group versus 88.17 ± 4.847 for the control group after 1 h of patients' positioning. The PaO2 /FiO2 ratio increased in the APP group before proning compared with 1 h after proning (79.95 ± 22.508 vs. 98.91 ± 34.44) respectively. APP improved the SpO2 , PaO2 /FiO2 , ROX index, PaO2 , and SaO2 values for the APP group, representing an increase of 5.85%, 23.71%, 30.79%, 22.59%, and 5.26%, respectively. CONCLUSION: Awake proning in non-intubated patients with COVID-19 showed marked improvement in oxygenation and physiological parameters. RELEVANCE TO CLINICAL PRACTICE: This study provides evidence for critical care nurses to implement APP in non-intubated patients with COVID-19 to improve oxygenation and physiological parameters, as it was tolerated by most of the patients without serious adverse events.

Lung ultrasound to predict gas-exchange response to prone positioning in COVID-19 patients: A prospective study in pilot and confirmation cohorts.

PURPOSE: To examine whether lung ultrasound prior to prone positioning can predict the resulting gas-exchange response. MATERIALS AND METHODS: This is a prospective observational study on critically-ill COVID-19 patients with a pilot and confirmation cohort. Lung ultrasound examinations were performed before prone positioning and gas-exchange parameters were recorded before and after position change. RESULTS: A total of 79 patients, 36 in the pilot cohort and 43 in the confirmation cohort, were included. In the pilot cohort, a moderate correlation between pre-turn lung ultrasound score index (LUSI) and change in PaO2/FiO2 after prone positioning was found. These findings were corroborated and extended upon in the confirmation cohort. The confirmation cohort found that anterior LUSI had the strongest correlation with follow-up time-points 1, 6, 12, and 24 h after prone positioning, with strength of correlation gradually increasing up to 24 h. In a multivariate model anterior aeration loss (odds ratio 0.035; 95%CI 0.003-0.319 for anterior LUSI >50%) and higher pre-turn PaCO2 (odds ratio 0.479 95% CI 0.235-0.979) were negatively predictive of a PaO2/FiO2 increase ≥20 mmHg. CONCLUSIONS: Anterior LUSI, in addition to other clinical parameters, may be used to aid COVID-19 respiratory strategy and a clinician's decision to prone.

Prone Positioning for Acute Hypoxemic Respiratory Failure and ARDS: A Review.

Prone positioning is an immediately accessible, readily implementable intervention that was proposed initially as a method for improvement in gas exchange > 50 years ago. Initially implemented clinically as an empiric therapy for refractory hypoxemia, multiple clinical trials were performed on the use of prone positioning in various respiratory conditions, cumulating in the landmark Proning Severe ARDS Patients trial, which demonstrated mortality benefit in patients with severe ARDS. After this trial and the corresponding meta-analysis, expert consensus and societal guidelines recommended the use of prone positioning for the management of severe ARDS. The ongoing COVID-19 pandemic has brought prone positioning to the forefront of medicine, including widespread implementation of prone positioning in awake, spontaneously breathing, nonintubated patients with acute hypoxemic respiratory failure. Multiple clinical trials now have been performed to investigate the safety and effectiveness of prone positioning in these patients and have enhanced our understanding of the effects of the prone position in respiratory failure. In this review, we discuss the physiologic features, clinical outcome data, practical considerations, and lingering questions of prone positioning.

Psychological Stress Induced by Prone Positioning among Adults with Severe Cerebral Palsy.

The purpose of this study was to investigate the psychological impact of various positionings in subjects with cerebral palsy (CP). The participants were 17 individuals with severe motor and intellectual disability due to CP. They began in a sitting position in their wheelchair, and were placed consecutively in prone or supine positions, with no intervals between placements. Physiological observations were made in each position, and included salivary α-amylase activity, pulse, percutaneous oxygen saturation, respiratory rate, learance or not of airway secretions, and occurrence or not of adverse events. Salivary α-amylase activity values were higher in the prone position than in the baseline and supine positions (p<0.05). Clearance of airway secretions was significantly more prevalent in the prone position than in the baseline and supine positions (p <0.05). The participants' pulse was significantly lower in the supine and prone positions than in the baseline position (p<0.05). Greater prevalence of airway secretion clearance and significantly higher stress levels as indicated by saliva amylase were observed in the prone position than in the other two positions. Therefore, when such patients are placed in a prone position, close attention to airway management and the potential for psychological stress may be necessary.

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.

RéSUMé: OBJECTIF: La position ventrale peut entraîner une compression anatomique de la cavité thoracique provoquant une réduction du débit cardiaque, en particulier dans le contexte de déformations de la paroi thoracique, fréquentes chez les patients atteints de scoliose. Il n'existe aucun protocole guidant l'utilisation de l'échocardiographie transœsophagienne (ETO) pour optimiser le positionnement ventral et pour favoriser l'utilisation sécuritaire de l'ETO dans les cas nécessitant un neuro-monitorage. CARACTéRISTIQUES CLINIQUES: Nous présentons le cas d'un homme de 23 ans atteint d'un syndrome de Cornelia de Lange bénéficiant d'une fusion spinale postérieure non urgente pour traiter une scoliose syndromique; le patient a manifesté une hypotension réfractaire sévère et un arrêt cardiaque en position ventrale. Après stabilisation hémodynamique à l'unité de soins intensifs, le patient est retourné en salle d'opération au jour postopératoire 2 pour terminer sa fusion spinale. L'échocardiographie transœsophagienne a permis de déterminer la position optimale des traversins longitudinaux qui était associée à une compression ventriculaire gauche minimale en décubitus dorsal. Le patient a ensuite été positionné sur le ventre, et les valeurs hémodynamiques peropératoires sont restées stables au cours de la deuxième chirurgie. En raison des considérations particulières de l'utilisation de l'ETO en position ventrale avec neuro-monitorage, nous décrivons les aspects techniques à prendre en compte pour protéger l'équipement et le patient. CONCLUSION: Les patients présentant des parois thoraciques compliantes ou des déformations thoraciques sont à risque d'instabilité hémodynamique en position ventrale. L'ETO peropératoire peut être utilisée chez le patient en décubitus dorsal avant le positionnement ventral pour déterminer le positionnement optimal des traversins longitudinaux afin de minimiser la compression cardiaque. L'utilisation de l'échocardiographie transœsophagienne lors d'une chirurgie du rachis en position ventrale avec neuro-monitorage et potentiels évoqués moteurs nécessite des considérations particulières en ce qui a trait à la sécurité des patients.