Bronchospasm in obese patients undergoing elective laparoscopic surgery under general anesthesia

Can intubate, cannot ventilate: A proposed algorithm to handle problems with ventilation and oxygenation after intubation

BACKGROUND AND METHODS

Few guidelines address how to handle unanticipated ventilatory problems and hypoxemia in a successfully intubated patient. We will refer to this situation as "can intubate-cannot ventilate." The situation may occur immediately after intubation or later during general anaesthesia. The aim of this paper is to describe an algorithm for handling this situation. In an intubated patient, the airway can be considered a continuum from the ventilator to the alveoli, and the problem is somewhere along this route: Ventilator → Hoses → Filter → Tracheal tube (TT) → Tracheae → Bronchi → Bronchioles → Alveoli. The proposed algorithm is based on clinical experience and has not been externally validated.

RESULTS

The first critical decision to be made is whether the TT has been placed correctly in the trachea or not. Positive wave-formed capnography is the primary marker for correct intubation. Video and/or direct laryngoscopy can be used for further verification. The patient should be disconnected from the ventilator and manually ventilated with bag-valve and 100% oxygen. An open tube should then be verified by applying a suction catheter through the tube. If these measures do not improve the situation, a fibreoptic scope should be inserted to further assess possible causes of difficult ventilation. If no obvious treatable cause is detected at this point, bronchospasm, anaphylaxis, or pneumothorax should be ruled out or treated. Further handling should focus on optimizing gas exchange in the lungs and considering more advanced treatment options to improve oxygenation and circulation.

CONCLUSIONS

We have proposed an algorithm to handle unanticipated problems with ventilation and oxygenation in a patient who has been successfully intubated. Equipment failure and a blocked TT should be ruled out before diagnosing and treating medical or surgical causes of ventilatory problems.

EDITORIAL COMMENT

This article presents a logical approach to the time-sensitive and critical situation where, for some reason, after intubation, ventilation of the lungs is not succeeding. The authors propose steps for a systematic approach, and recognition of different possible explanations for ventilation not working is informative.

Right place, no trace: A case report of postintubation bronchospasm

Evidence suggests obesity correlates with airway hyperreactivity, which can result in severe bronchospasm. This report presents a 31-year-old female with a high body mass index who presented for a laparoscopic hysterectomy and bilateral salpingo-oophorectomy. She had no past medical or atopic history. After induction of anaesthesia and intubation, O2 saturation fell with no CO2 trace, breathing sounds or chest rise. Despite confirming endotracheal tube position by video laryngoscopy, the CO2 trace remained flat and mechanical ventilation was difficult with high airway pressures. Blood pressure was stable with no mucocutaneous signs of anaphylaxis. Administration of 100% O2, bronchodilators and steroids improved ventilation and oxygenation with a return of a CO2 trace. The operation was postponed. Prior to her subsequent surgery, the patient was premedicated with inhaled steroids and long-acting beta agonist with an uneventful induction and intubation. Giving a rising obese population, this case report aims to educate anaesthetists and anaesthetic practitioners as to the presentation, risk factors, mechanisms and management of uncommon, life-threatening postintubation bronchospasm.

Atracurium-Induced Bronchospasm With Flat Capnograph at Induction of General Anaesthesia: A Case Report

Benzylisoquinolinium neuromuscular blocking agents can precipitate bronchospasm either through allergy/anaphylaxis or isolated stimulation of mast cell histamine release. This report presents a 75-year-old female who attended the day surgery unit for a rigid cystoscopy under general anaesthesia. She had a hyper-reactive airway history of mild historic asthma and sensitivity to aerosols. After administration of atracurium at induction of anaesthesia, ventilation became challenging with no chest rise and a flat CO2 trace. Repeat video laryngoscopy confirmed correct endotracheal tube position. The patient remained cardiovascularly stable with no mucocutaneous signs of anaphylaxis. Administration of high flow oxygen, sevoflurane, salbutamol and magnesium sulfate led to gradual improvement and normalisation of respiratory parameters. Surgery was postponed. This report highlights atracurium as an important trigger of bronchospasm at induction of anaesthesia, and illustrates that in rare cases a flat capnograph does not always indicate a mispositioned airway device. Several aspects of the anaesthetic plan for this patient were suboptimal given her respiratory history, namely, the choice of mode of anaesthesia and choice of neuromuscular blocking agent. These factors are discussed in the context of anaesthetic planning for patients presenting with features suggesting high bronchospastic risk.

Does the pleth variability index have any predictive value for intraoperative respiratory problems in bariatric surgery?

Background/aim

We aimed to search the relationship between the preoperative PVI (pleth variability index) and intraoperative respiratory parameters to reveal whether PVI can be used as a prediction tool in bariatric surgery.

Materials and methods

Forty patients undergoing bariatric surgery were included. Noninvasive pleth variability index measured via finger probe before induction of general anesthesia. Following intubation each patient was ventilated in controlled mode. Intraoperative blood pressure, peak airway pressure, end-tidal CO2, SpO2, PEEP, and FiO2 were recorded every 5 min for the first 10 min and then every 10 min until extubation. Steroid and bronchodilator requirements were recorded.

Results

The systolic pressure-PVI, oxygen saturation-PVI relationship was statistically significant (p = 0.03, p = 0.013). A relationship was found between pleth variability index and peak airway pressure (p = 0.002). No correlation was detected between end-tidal CO2 and pleth variability index. The relationship between steroid, bronchodilator use, and PVI was significant (p = 0.05, p = 0.01). A positive correlation between PEEP and PVI was detected at varying time points. A positive correlation was found between FiO2-PVI.

Conclusion

A relationship was found between PVI and intraoperative peak airway pressures, oxygen saturation, PEEP, bronchodilatator, and steroid usage. This result may be inspiring to conduct larger studies addressing the issue of predicting intraoperative respiratory problems in bariatric surgeries.

Perioperative Anaphylaxis

Perioperative anaphylaxis is a potentially life-threatening and under-recognized event most commonly caused by antibiotics, neuromuscular blocking agents, dyes, latex, and disinfectants. This review provides updates in the epidemiology and pathogenesis of perioperative anaphylaxis, discusses culprit agents, and highlights the tenets of management including a comprehensive allergy evaluation.

The effect of low flow anesthesia on hemodynamic and peripheral oxygenation parameters in obesity surgery

Objectives:

To investigate the effects of low-flow anesthesia on hemodynamic parameters and recovery from anesthesia in obese individuals undergoing laparoscopic surgery.

Methods:

This randomized-controlled and prospective study included 44 obese patients who underwent laparoscopic sleeve gastrectomy operation. The patients were randomly allocated into 2 groups as low-flow and high-flow anesthesia. Further, the groups compared in terms of hemodynamic parameters, anesthesia recovery times, operation times, and arterial blood gas parameters.

Results:

The groups were similar with respect to demographic data. Heart rate, peripheral oxygen saturation, arterial blood pressure measurements, end-tidal, and CO₂, lactate levels measurements were similar in both groups during the entire procedure. There was also no statistically significant difference in terms of arterial blood gas parameters or anesthesia recovery periods.

Conclusion:

Low-flow anesthesia in laparoscopic obesity surgery seems to be safer compared to high-flow anesthesia in terms of the adequacy of tissue perfusion, depth of anesthesia, and postoperative recovery.

Nutrient intake is a predictor of lung function in obese asthmatic adolescents undergoing interdisciplinary therapy

Asthma-obesity is a multifactorial disease with specific asthma phenotypes that aggravate due to overweight and an unbalanced diet. Furthermore, obese asthmatic patients are corticotherapy-resistant. Therefore, the aims of the present study were to evaluate the effects of an interdisciplinary intervention on food consumption, body composition, lung function and adipokines in asthmatic and non-asthmatic obese adolescents and to investigate the influence of nutrients on lung function. Obese non-asthmatic (n 42) and obese asthmatic (n 21) adolescents of both sexes were enrolled in the present study. Food intake, adipokine levels, body composition, asthma symptoms and lung function were assessed across the study. After the intervention of 1 year, there was a reduction (P ≤ 0·01) in BMI, body fat percentage, visceral and subcutaneous fat and an increase (P ≤ 0·01) in lean mass and all lung function variables in both groups, except the relation between forced expiratory volume in 1 s and forced vital capacity (FEV1:FVC) in non-asthmatic patients. Moreover, both groups decreased lipid and cholesterol consumption (P ≤ 0·01). The highest energy consumption (β = -0·021) was associated with lower values of FVC. Similarly, carbohydrate consumption (β = -0·06) and cholesterol were negative predictors (β = -0·05) in FEV1:FVC. However, the consumption of Ca (β = 0·01), fibres (β = 1·34) and vitamin A (β = 0·01) were positive predictors of FEV1:FVC. Asthma-obesity interdisciplinary treatment promoted an improvement on food consumption and lung function in adolescents and demonstrated that the consumption of nutrients influenced an increase in lung function.

Do Difficult Airway Techniques Predispose Obese Patients to Bronchospasm?

Objective

The existing evidence separately correlates morbid obesity with difficult intubation and bronchospasm. However, there is a lack of data on whether anaesthesia provider manipulations during difficult intubation contribute to an increased ratio of bronchospasm in these patients.

Methods

This is a retrospective analysis of data prospectively taken from 50 morbidly obese patients involved in a previously published study. A possible difficult intubation was preoperatively investigated by recording the following specific physical examination indices: Mallampati and Cormack-Lehane (CL) classifications, cervical spine mobility (CSM), thyromental distance (Td) and patients' ability to open their mouth (mouth opening). Bronchospasm was clinically detected by auscultation and confirmed by measuring peak airway pressures during mechanical ventilation. The Kruskal-Wallis H test was used for data analysis, followed by the Mann-Whitney U test as applicable.

Results

Different physical examination prognostic indices, including Mallampati and CL scales (p<0.001; the CSM excluded -p=0.790), showed that they are related to difficult intubation. Bronchospasm not attributable to difficult intubation was observed in six obese patients.

Conclusion

Patients with morbid obesity constitute an increased relative risk group as far as difficult intubation is concerned, particularly if preoperative findings support a relationship between the two variables examined. In our study, difficult intubation and the concomitant use of special equipment and manipulations did not contribute to an increased rate of bronchospasm in obese patients, but in view of the lack of data, a large number of more sophisticated studies are required to elucidate such an assumption.