Vital capacity manoeuvre in general anaesthesia: useful or useless?:

Impact of home quarantine on physical fitness of school-aged children in Xi'an during COVID-19 lockdown: a cross-sectional study

BACKGROUND

The emergence of the COVID-19 pandemic has sparked unprecedented global challenges. This study intends to investigate changes in the physical fitness of students aged 6-22 during the COVID-19 pandemic and to assess how the pandemic lockdown period affected these markers.

METHODS

According to the National Student Physical Health Standard, a stratified cluster sampling method was used to evaluate the body shape, body function, and physical fitness of children and adolescents (n = 8092) in Xi'an from 2019 to 2021. This study uses SPSS 26.0 (IBM, Chicago, IL, USA) for data statistics and analysis. The connection between physical fitness and years was measured using the one-variable analysis in the general linear model (GLM). Independent t-tests were used to determine the sex (male/female) and area (urban/rural) differences.

RESULTS

During the lockdown period, Body Mass Index (BMI) and flexibility showed an upward trend, while aerobic, strength, speed, and endurance showed a downward trend. In addition to the BMI of middle and high school students, almost all indicators show significant sex differences. There are urban-rural differences in some indicators, such as chin-ups.

CONCLUSION

During the pandemic of COVID-19, the physical fitness of children and adolescents in Xi'an did not change significantly, and there were slight differences among different grades. During the pandemic lockdown period, lifestyle changes and reduced outdoor activities for children and adolescents may be the reasons for the changing trend of various indicators.

Trends in Physical Fitness and Nutritional Status among School-Aged Children and Adolescents during the COVID-19 Pandemic in Shaanxi, China-A Cross-Sectional Study

BACKGROUND

This study aimed to explore the characteristics of trends in physical fitness and nutritional status among school-aged students during the COVID-19 pandemic, which could help to develop targeted guidelines and policies for students (adolescents) to promote health during lockdowns resulting from public health emergencies.

METHODS

The physical fitness and nutritional status were measured from 2019 to 2021; the correlation between years and grade were analyzed.

RESULTS

a declining trend was found in aerobic fitness, strength fitness, speed fitness, and BMI during this lockdown.

CONCLUSION

The changes in dietary behavior and the decrease in outdoor physical activities may be the reason for the decline. Furthermore, differences in subjects' growth and limited space at home must be considered in the formulation of exercise and nutritional plans. According to the results of our study, exercise for aerobic fitness should receive more attention when students are enduring a pandemic lockdown. In addition, saying "no" to high-calorie foods in the form of snacking and ultra-processed food was the key to improving subjects' nutritional status.

Definition and clinical evaluation of a recruiting airway pressure based on the specific lung elastance in anesthetized dogs

OBJECTIVE

To determine the specific lung elastance (SE_L) in anesthetized dogs and to evaluate the efficacy of a SE_L-based recruiting airway pressure (RP_aw) at improving global and regional lung aeration.

STUDY DESIGN

Retrospective and prospective clinical study.

ANIMALS

A total of 28 adult dogs were included in the retrospective study and six adult dogs in the prospective study.

METHODS

Retrospective study: SE_L and SE_L-based RP_aw were determined using previously published data. In mechanically ventilated dogs undergoing thoracic computed tomography (CT), SE_L was calculated as ΔP_L/(V_T/EELV), where ΔP_L is the driving transpulmonary pressure, V_T is the tidal volume and EELV is the end-expiratory lung volume. The ratio of lung to respiratory system elastance (E_L/E_rs) was determined. SE_L and E_L/E_rs were used to calculate the SE_L-based RP_aw. Prospective study: dogs underwent thoracic CT at end-expiration and at end-inspiration using the SE_L-based RP_aw, and global and regional aeration was determined. For analysis of regional aeration, lungs were divided into cranial, intermediate and caudal regions. Regional compliance was also calculated. A p value <0.05 was considered significant.

RESULTS

The SE_L and E_L/E_rs were 12.7 ± 3.1 cmH₂O and 0.54 ± 0.07, respectively. The SE_L-based RP_aw was 29.1 ± 7.6 cmH₂O. In the prospective study, the RP_aw was 28.2 ± 1.3 cmH₂O. During RP_aw, hyperinflation increased (p = 0.0003) whereas poorly aerated (p < 0.0001) and nonaerated (p = 0.01) tissue decreased. Normally aerated tissue did not change (p = 0.265). Regional compliance was higher in the intermediate (p = 0.0003) and caudal (p = 0.034) regions compared with the cranial region. Aeration did not differ between regions (p > 0.05).

CONCLUSIONS AND CLINICAL RELEVANCE

An SE_L-based RP_aw reduces poorly and nonaerated lung tissue in anesthetized dogs. In nonsurgical anesthetized dogs, an RP_aw near 30 cmH₂O is effective at improving lung aeration.

Different strategies for mechanical VENTilation during CardioPulmonary Bypass (CPBVENT 2014): study protocol for a randomized controlled trial

Background

There is no consensus on which lung-protective strategies should be used in cardiac surgery patients. Sparse and small randomized clinical and animal trials suggest that maintaining mechanical ventilation during cardiopulmonary bypass is protective on the lungs. Unfortunately, such evidence is weak as it comes from surrogate and minor clinical endpoints mainly limited to elective coronary surgery. According to the available data in the academic literature, an unquestionable standardized strategy of lung protection during cardiopulmonary bypass cannot be recommended. The purpose of the CPBVENT study is to investigate the effectiveness of different strategies of mechanical ventilation during cardiopulmonary bypass on postoperative pulmonary function and complications.

Methods/design

The CPBVENT study is a single-blind, multicenter, randomized controlled trial. We are going to enroll 870 patients undergoing elective cardiac surgery with planned use of cardiopulmonary bypass. Patients will be randomized into three groups: (1) no mechanical ventilation during cardiopulmonary bypass, (2) continuous positive airway pressure of 5 cmH₂O during cardiopulmonary bypass, (3) respiratory rate of 5 acts/min with a tidal volume of 2–3 ml/Kg of ideal body weight and positive end-expiratory pressure of 3–5 cmH₂O during cardiopulmonary bypass. The primary endpoint will be the incidence of a PaO₂/FiO₂ ratio <200 until the time of discharge from the intensive care unit. The secondary endpoints will be the incidence of postoperative pulmonary complications and 30-day mortality. Patients will be followed-up for 12 months after the date of randomization.

Discussion

The CPBVENT trial will establish whether, and how, different ventilator strategies during cardiopulmonary bypass will have an impact on postoperative pulmonary complications and outcomes of patients undergoing cardiac surgery.

Trial registration

ClinicalTrials.gov, ID: NCT02090205. Registered on 8 March 2014.

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-017-2008-2) contains supplementary material, which is available to authorized users.

Ventilatory strategies for hypoxemia during cardiac surgery: survey validation for anesthesiologists in Brazil

BACKGROUND AND OBJECTIVES

Perioperative hypoxemia is common in cardiac surgeries, and atelectasis is the main cause. Besides, we can mention extracorporeal circulation (ECC), dissection of internal thoracic arteries, and previous clinical status of the patient among others as its causes. The present study elaborated an anonymous questionnaire to observe ventilatory strategies for hypoxemia in cardiac surgeries adopted by five thousand anesthesiologists all over the country.

METHODS

Questionnaires were sent via e-mail for five thousand anesthesiologists in Brazil.

RESULTS

Out of the questionnaires sent, 81 valid responses were received. Among the answers, 65 (80%) anesthesiologists use volume-controlled ventilation (VCV), while 16 (20%) prefer pressure-controlled ventilation (PCV). The tidal volume (Vt) used is lower than 10 mL.kg(-1), for 46 (61%) versus 20 (30%) who adopt a Vt greater than 10 mL.kg(-1). Forty-seven (58%) use PEEP and 15 (21%) use FiO(2) above 60%. In the case of intraoperative hypoxemia, 20.9% increase or introduce PEEP, 70.3% increase the FiO(2), 19.7% use alveolar recruitment maneuvers, 13.5% increase the tidal volume, and 20.9% check for the presence of failures in the anesthesia equipment. Responses were sent from 15 states.

CONCLUSIONS

The conducts described in the questionnaires are compatible with those of the international literature. Adjusting the questionnaires format and the way to approach anesthesiologists, new studies could be undertaken.

[Peri-operative atelectasis and alveolar recruitment manoeuvres]

Respiratory complications are a significant cause of post-operative morbidity and mortality. Peri-operative atelectasis, in particular, affects 90% of surgical patients and its effects can be prolonged, due to changes in respiratory mechanics, pulmonary circulation and hypoxaemia. Alveolar collapse is caused by certain predisposing factors, mainly by compression and absorption mechanisms. To prevent or treat these atelectasis several therapeutic strategies have been proposed, such as alveolar recruitment manoeuvres, which has become popular in the last few years. Its application in patients with alveolar collapse, but without a previous significant acute lung lesion, has some special features, therefore its use is not free of uncertainties and complications. This review describes the frequency, pathophysiology, importance and treatment of peri-operative atelectasis. Special attention is paid to treatment with recruitment manoeuvres, with the purpose of providing a basis for the their rational and appropriate use.

Effects of early vital capacity maneuver on respiratory variables during multivessel off-pump coronary artery bypass graft surgery

OBJECTIVES

Despite avoiding cardiopulmonary bypass, similar degrees of pulmonary impairment compared with on-pump coronary artery bypass surgery have been demonstrated in patients undergoing off-pump coronary artery bypass graft surgery (OPCAB) compared with on-pump coronary artery bypass surgery. To investigate the effects of an early vital capacity maneuver (VCM) on intrapulmonary shunt (Qs/Qt), oxygenation, and pulmonary outcome in OPCAB.

DESIGN

Prospective, randomized, controlled, double-blind clinical trial.

SETTING

Cardiothoracic operating room and intensive care unit (ICU) of a university hospital.

PATIENTS

Fifty patients scheduled for OPCAB were randomized to treatment with VCM or none.

INTERVENTIONS

After sternotomy, VCM was performed by inflating the lungs to 40 cm H2O and holding this pressure for 10 seconds.

MEASUREMENTS AND MAIN RESULTS

Qs/Qt, Pao2/Fio2 (P/F) ratio, and dynamic and static pulmonary compliances were measured before induction of anesthesia (T0), 15 minutes after tracheal intubation (T1), during Y-graft construction (T2), 15 minutes after completion of grafting (T3), 15 minutes after sternal closure (T4), and 3 hours after arrival at the ICU (T5). Qs/Qt was lower and P/F ratio was higher in the VCM group at T2 through T5. Pulmonary compliances were also higher in the VCM group at T4 and T5. Patients in the VCM group were extubated earlier.

CONCLUSIONS

The beneficial effects of an early VCM on Qs/Qt persisted into the period of ICU care, with an improvement in P/F ratio and preserved pulmonary compliances, leading to a shorter time to extubation.

The carrier gas in anaesthesia: nitrous oxide/oxygen, medical air/oxygen and pure oxygen

PURPOSE OF REVIEW

The gas passing the module for the delivery of inhalation anaesthetics and carrying vapourized anaesthetics into the breathing system is called the carrier gas. Oxygen is the absolutely indispensable component of the carrier gas. Additive gaseous components can be medical air (nitrogen), nitrous oxide, cyclopropane, or xenon, the latter three being anaesthetic gases themselves. Cyclopropane is not used any more and xenon is not approved as a medical gas yet, leaving medical air and nitrous oxide as the only currently available adjuncts to oxygen.

RECENT FINDINGS

As review articles on nitrous oxide recommend unequivocally not using this gas routinely, and many anaesthetists already consistently omit any use of this gas, the alternative carrier gases are either a mixture of medical air and oxygen or pure oxygen. A nitrogen/oxygen mixture is absolutely inert with respect to metabolism or environment; there are no contraindications or shortcomings at all. The use of pure oxygen will result in high oxygen concentrations, improving the patients' safety by increasing the pulmonary oxygen reservoir and rendering impossible the development of hypoxic gas mixtures within the breathing system. Whether the incidence of postoperative wound infections or postoperative nausea and vomiting is reduced by perioperative hyperoxia is still under scientific discussion. In general, the use of high oxygen concentrations over a period of 6-8 h is not harmful for the patient, assuming the performance of recruitment manoeuvres, consistent use of positive end-expiratory pressure, and thorough observance of the contraindications that can result from the increased vulnerability of tissues to hyperoxia.

SUMMARY

Nitrous oxide should not be used routinely as a component of the carrier gas any more. A mixture of medical air and oxygen must be acknowledged to be the gold standard. Pure oxygen may be used as a carrier gas if medical air or properly performing flow controls for medical air are not available.

Thoracic sympathetic block reduces respiratory system compliance

CONTEXT AND OBJECTIVE

Thoracic epidural anesthesia (TEA) following thoracic surgery presents known analgesic and respiratory benefits. However, intraoperative thoracic sympathetic block may trigger airway hyperreactivity. This study weighed up these beneficial and undesirable effects on intraoperative respiratory mechanics.

DESIGN AND SETTING

Randomized, double-blind clinical study at a tertiary public hospital.

METHODS

Nineteen patients scheduled for partial lung resection were distributed using a random number table into groups receiving active TEA (15 ml 0.5% bupivacaine, n = 9) or placebo (15 ml 0.9% saline, n = 10) solutions that also contained 1:200,000 epinephrine and 2 mg morphine. Under general anesthesia, flows and airway and esophageal pressures were recorded. Pressure-volume curves, lower inflection points (LIP), resistance and compliance at 10 ml/kg tidal volume were established for respiratory system, chest wall and lungs. Students t test was performed, including confidence intervals (CI).

RESULTS

Bupivacaine rose 5 +/- 1 dermatomes upwards and 6 +/- 1 downwards. LIP was higher in the bupivacaine group (6.2 +/- 2.3 versus 3.6 +/- 0.6 cmH2O, p = 0.016, CI = -3.4 to -1.8). Respiratory system and lung compliance were higher in the placebo group (respectively 73.3 +/- 10.6 versus 51.9 +/- 15.5, p = 0.003, CI = 19.1 to 23.7; 127.2 +/- 31.7 versus 70.2 +/- 23.1 ml/cmH2O, p < 0.001, CI = 61 to 53). Resistance and chest wall compliance showed no difference.

CONCLUSION

TEA decreased respiratory system compliance by reducing its lung component. Resistance was unaffected. Under TEA, positive end-expiratory pressure and recruitment maneuvers are advisable.