Effects of thoracic epidural anaesthesia on pulmonary venous admixture and oxygenation during one-lung ventilation

Impact of pharmacological interventions on intrapulmonary shunt during one-lung ventilation in adult thoracic surgery: a systematic review and component network meta-analysis

BACKGROUND

Intrapulmonary shunt is a major determinant of oxygenation in thoracic surgery under one-lung ventilation. We reviewed the effects of available treatments on shunt, Pao₂/FiO₂ and haemodynamics through systematic review and network meta-analysis.

METHODS

Online databases were searched for RCTs comparing pharmacological interventions and intrapulmonary shunt in thoracic surgery under one-lung ventilation up to March 30, 2022. Random-effects (component) network meta-analysis compared 24 treatments and 19 treatment components. The Confidence in Network Meta-Analysis (CINeMA) framework assessed evidence certainty. The primary outcome was intrapulmonary shunt fraction during one-lung ventilation.

RESULTS

A total of 55 RCTs were eligible for systematic review (2788 participants). The addition of N₂O (mean difference [MD]=-15%; 95% confidence interval [CI], -25 to -5; P=0.003) or almitrine (MD=-13%; 95% CI, -20 to -6; P<0.001) to propofol anaesthesia were efficient at decreasing shunt. Combined epidural anaesthesia (MD=3%; 95% CI, 1-5; P=0.005), sevoflurane (MD=5%; 95% CI, 2-8; P<0.001), isoflurane (MD=6%; 95% CI, 4-9; P<0.001), and desflurane (MD=9%; 95% CI, 4-14; P=0.001) increased shunt vs propofol. Almitrine (MD=147 mm Hg; 95% CI, 58-236; P=0.001), dopexamine (MD=88 mm Hg; 95% CI, 4-171; P=0.039), and iloprost (MD=81 mm Hg; 95% CI, 4-158; P=0.038) improved Pao₂/FiO₂. Certainty of evidence ranged from very low to moderate.

CONCLUSIONS

Adding N₂O or almitrine to propofol anaesthesia reduced intrapulmonary shunt during one-lung ventilation. Halogenated anaesthetics increased shunt in comparison with propofol. The effects of N₂O, iloprost, and dexmedetomidine should be investigated in future research. N₂O results constitute a research hypothesis currently not backed by any direct evidence. The clinical availability of almitrine is limited.

SYSTEMATIC REVIEW PROTOCOL

PROSPERO CRD42022310313.

The hypoxic pulmonary vasoconstriction: From physiology to clinical application in thoracic surgery

More than 70 years after its original report, the hypoxic pulmonary vasoconstriction (HPV) response continues to spark scientific interest on its mechanisms and clinical implications, particularly for anesthesiologists involved in thoracic surgery. Selective airway intubation and one-lung ventilation (OLV) facilitates the surgical intervention on a collapsed lung while the HPV redirects blood flow from the "upper" non-ventilated hypoxic lung to the "dependent" ventilated lung. Therefore, by limiting intrapulmonary shunting and optimizing ventilation-to-perfusion (V/Q) ratio, the fall in arterial oxygen pressure (PaO₂) is attenuated during OLV. The HPV involves a biphasic response mobilizing calcium within pulmonary vascular smooth muscles, which is activated within seconds after exposure to low alveolar oxygen pressure and that gradually disappears upon re-oxygenation. Many factors including acid-base balance, the degree of lung expansion, circulatory volemia as well as lung diseases and patient age affect HPV. Anesthetic agents, analgesics and cardiovascular medications may also interfer with HPV during the perioperative period. Since HPV represents the homeostatic mechanism for regional ventilation-to-perfusion matching and in turn, for optimal pulmonary oxygen uptake, a clear understanding of HPV is clinically relevant for all anesthesiologists.

Inhalational versus intravenous anesthetics during one lung ventilation in elective thoracic surgeries: A narrative review

The anesthesia regimen used during one lung ventilation (OLV) carry the potential to affect intra-operative course and post-operative outcomes, by its effects on pulmonary vasculature and alveolar inflammation. This narrative review aims to understand the pathophysiology of acute lung injury during one lung ventilation, and to study the effects of inhalational versus intravenous anaesthetics on intraoperative and post-operative outcomes, following thoracic surgery. For this purpose, we independently searched 'PubMed', 'Google Scholar' and 'Cochrane Central' databases to find out randomized controlled trials (RCTs), in English language, which compared the effects of intravenous versus inhalational anaesthetics on intraoperative and post-operative outcomes, in elective thoracic surgeries, in human beings. In total, 38 RCTs were included in this review. Salient results of the review are- Propofol reduced intraoperative shunt and maintained better intraoperative oxygenation than inhalational agents. However, use of modern inhalational anaesthetics during OLV reduced alveolar inflammation significantly, as compared to propofol. Regarding post-operative complications, the evidence is not conclusive enough but slightly in favour of inhalational anaesthetics. Thus, we conclude that modern inhalational anaesthetics, by their virtue of better anti-inflammatory properties, exhibit lung protective effects and hence, seem to be safe for maintenance of anesthesia during OLV in elective thoracic surgeries. Further research is required to establish the safety of these agents with respect to long term post-operative outcomes like cancer recurrence.

Intraoperative Anesthetic Management of the Thoracic Patient

The intraoperative anesthetic management for thoracic surgery can impact a patient's postoperative course, especially in patients with significant lung disease. One-lung ventilation poses an inherent risk to patients, including hypoxemia, acute lung injury, and right ventricular dysfunction. Patient-specific ventilator management strategies during one-lung ventilation can reduce postoperative morbidity.

Nebulized dexmedetomidine improves pulmonary shunt and lung mechanics during one-lung ventilation: a randomized clinical controlled trial

Background

Dexmedetomidine (Dex), a selective a₂-adrenergic receptor agonist, has been previously reported to attenuate intrapulmonary shunt during one-lung ventilation (OLV) and to alleviate bronchoconstriction. However, the therapeutic effects of nebulized Dex on pulmonary shunt and lung mechanics during OLV have not been evaluated. Here we determine whether nebulized dexmedetomidine improved pulmonary shunt and lung mechanics in patients undergoing elective thoracic surgery in a prospective randomized controlled clinical trial.

Methods

One hundred and twenty-eight patients undergoing elective thoracoscopic surgery were included in this study and randomly divided into four groups: 0.9% saline (Placebo group), 0.5 µg/kg (Dex_0.5 group), 1 µg/kg (Dex₁ group) and 2 µg/kg (Dex₂group) dexmedetomidine. After bronchial intubation, patients received different nebulized doses of dexmedetomidine (0.5 µg/kg, 1 µg/kg and 2 µg/kg) or 0.9% saline placebo during two-lung ventilation(TLV). OLV was initiated 15 min after bronchial intubation. Anesthesia was maintained with intravenous infusion of cisatracurium and propofol. Bispectral Index values were maintained within 40–50 by adjusting the infusion of propofol in all groups. Arterial blood gas samples and central venous blood gas samples were taken as follows: 15 min after bronchial intubation during two-lung ventilation (TLV₁₅), after 30 and 60 min of OLV (OLV₃₀and OLV₆₀, respectively) and 15 min after reinstitution of TLV (ReTLV). Dynamic compliance was also calculated at TLV₁₅, OLV₃₀, OLV₆₀ and ReTLV.

Results

Dex decreased the requirement of propofol in a dose-dependent manner(P = 0.000). Heart rate (HR) and mean arterial pressure (MAP) displayed no significant difference among groups (P = 0.397 and 0.863). Compared with the placebo group, Dex administered between 0.5 and 2 µg/kg increased partial pressure of oxygen (P_aO₂) significantly at OLV₃₀ and OLV₆₀(P = 0.000); however, Dex administered between 1 and 2 µg/kg decreased pulmonary shunt fraction (Q_s/Q_t) at OLV₃₀ and OLV₆₀(P = 0.000). Compared with the placebo group, there were significant increases with dynamic compliance (Cdyn) after OLV in Dex_0.5, Dex₁ and Dex₂group(P = 0.000). Conclusions. Nebulized dexmedetomidine improved oxygenation not only by decreasing pulmonary shunt but also by improving lung compliance during OLV, which may be effective in managing OLV.

Effects of bronchial blockers on one-lung ventilation in general anesthesia: A randomized controlled trail

BACKGROUND

Double-lumen bronchial tubes (DLBT) and bronchial blockers (BB) are commonly used in the anesthesia for clinical thoracic surgery. But there are few systematic clinical comparisons between them. In this study, the effects of BB and DLBT on one-lung ventilation (OLV) are studied.

METHODS

The 200 patients with thoracic tuberculosis undergoing thoracic surgery, were randomly assigned to group A (DLBT) and group B (BB). Intubation time, hemodynamic changes (mean arterial pressure [MAP], heart rate [HR]), and arterial blood gas indicators (arterial partial pressure of carbon dioxide [PaCO2], arterial partial pressure of oxygen [PaO2], airway plateau pressure [Pplat], and airway peak pressure [Ppeak]) at 4 time points were recorded. Complications such as hoarseness, pulmonary infection, pharyngalgia, and surgical success rate were also evaluated postoperatively.

RESULTS

Intubation times were shorter in group B. Both MAP and HR in group A were significantly higher 1 minute after intubation than before, but also higher than those in group B. PaO2 levels were lower in both groups during (OLV) than immediately after anesthesia and after two-lung ventilation (TLV), with PaO2 being lower after 60 minutes of OLV than after 20 minutes of OLV. Furthermore, at both points during OLV, PaO2 was lower in group A than in group B. No significant differences in PaCO2 were found between the 2 groups. Ppeak and Pplat were increased in both groups during OLV, with both being higher in group A than in group B. The incidence of postoperative hoarseness, pulmonary infection, and pharyngalgia were lower in group B. There was no significant difference in the success rate of operation between the 2 groups.

CONCLUSIONS

Compare with using DLBT, implementation of BB in general anesthesia has less impact on hemodynamics, PaO2 and airway pressures, and achieves lower incidence of postoperative complication.

The Effects of Iloprost on Oxygenation During One-Lung Ventilation for Lung Surgery: A Randomized Controlled Trial

Hypoxemia can occur during one-lung ventilation (OLV) in thoracic surgery, leading to perioperative complications. Inhaled iloprost is a selective pulmonary vasodilator with efficacy in patients with pulmonary hypertension. The purpose of this study was to evaluate the effects of off-label inhaled iloprost on oxygenation during OLV in patients undergoing lung surgery. Seventy-two patients who were scheduled for elective video-assisted thoracoscopic lobectomy were assigned to receive an inhaled nebulizer of distilled water (control group), 10 μg iloprost (IL10 group), or 20 μg iloprost (IL20 group). Arterial and venous blood gas and hemodynamic analyses were obtained. Changes in partial pressure of oxygen in arterial blood (PaO₂), after the initiation of OLV and the resumption two-lung ventilation (TLV), were similar in all three groups. However, PaO₂ in the IL10 group was comparable to that in the control group, whereas PaO₂ in the IL20 group was significantly higher than that in the control group at 10, 20, and 30 min after administration of iloprost (275.1 ± 50.8 vs. 179.3 ± 38.9, p < 0.0001; 233.9 ± 39.7 vs. 155.1 ± 26.5, p < 0.0001; and 224.6 ± 36.4 vs. 144.0 ± 22.9, p < 0.0001, respectively). The shunt fraction in the IL20 group was significantly higher than that in the control group after administration of iloprost (26.8 ± 3.1 vs. 32.2 ± 3.4, p < 0.0001; 24.6 ± 2.2 vs. 29.9 ± 3.4, p < 0.0001; and 25.3 ± 2.0 vs. 30.8 ± 3.1, p < 0.0001, respectively). Administration of inhaled iloprost during OLV improves oxygenation and decreases intrapulmonary shunt.

Effects of Nicorandil Versus Nitroglycerin on Arterial Oxygenation During Two-Lung Ventilation and One-Lung Ventilation in Patients With Risk Factors for Myocardial Ischemia: A Prospective, Randomized, Double-Blind Study

OBJECTIVES

To compare the effects of nicorandil and nitroglycerin on arterial oxygenation during two-lung ventilation (TLV) and one-lung ventilation (OLV) in patients with risk factors for myocardial ischemia.

DESIGN

A prospective, randomized, double-blind study.

SETTING

A tertiary care hospital.

PARTICIPANTS

Fifty-six patients scheduled for elective video-assisted thoracic surgery were assigned randomly to either the nicorandil group or the nitroglycerin group.

INTERVENTIONS

Patients in the nicorandil group received a bolus dose of nicorandil, 0.08 mg/kg during induction of anesthesia, followed by a continuous infusion at a rate of 0.08 mg/kg/h. Patients in the nitroglycerin group received a continuous infusion of nitroglycerin at a rate of 1 µg/kg/min from the induction of anesthesia.

MEASUREMENTS AND MAIN RESULTS

Arterial blood gas analysis was performed at the following points: before induction of anesthesia; during TLV; at 5, 10, 20, and 30 minutes after the initiation of OLV. PaO₂ at TLV (479.7 ± 57.1 v 408.2 ± 70.9 mmHg, p < 0.001); and at 5 minutes (344.8 ± 85.1 v 282.6 ± 85.8 mmHg, p = 0.012), 20 minutes (215.7 ± 103.0 v 158.2 ± 74.5 mmHg, p = 0.027), and 30 minutes (198.8 ± 103.5 v 147.5 ± 64.1 mmHg, p = 0.039) after OLV was significantly higher in the nicorandil group than in the nitroglycerin group.

CONCLUSION

This study demonstrated that oxygenation during TLV and OLV was significantly higher in patients receiving nicorandil than in those receiving nitroglycerin.

[Anesthesia in thoracic surgery]

Thoracic surgery represents a special challenge for anesthesia and requires a high level of human and material resources. Accurate knowledge of the pathophysiology is essential for selection of the anesthetic procedure, the separation of the lungs, monitoring and treatment of hemodynamics as well as for postoperative follow-up care. The increasing number of thoracic interventions and patients who are often suffering from complex diseases require close interdisciplinary cooperation between surgeons, anesthesiologists and intensive care specialists. In addition to the anesthetic techniques particular attention must be paid to the prevention of perioperative complications that can have a relevant effect on patient outcome. In particular hypoxemia during one-lung ventilation influences postoperative morbidity and mortality. Protective pulmonary ventilation strategies play an important role in prevention of postoperative acute lung injury.

The effect of epidural dexmedetomidine on oxygenation and shunt fraction in patients undergoing thoracotomy and one lung ventilation: A randomized controlled study

Background and Aims:

Role of epidural dexmedetomidine in providing analgesia is well documented, but its effect on oxygenation and shunt fraction is not well established. We studied the hypothesis that epidural dexmedetomidine may improve oxygenation and shunt fraction during one-lung ventilation (OLV).

Material and Methods:

After taking Institutional Ethics Committee approval, sixty patients undergoing thoracotomy and OLV were randomized to receive epidural ropivacaine with saline (RS group) or epidural ropivacaine with dexmedetomidine (RD group). Group RS received 7 ml of ropivacaine 0.5% with 1.5 ml normal saline (NS) bolus while RD group received 7 ml of 0.5% ropivacaine with 1 mcg/kg dexmedetomidine reconstituted in 1.5 ml NS. This was followed by infusion of 5 ml/h of 0.5% ropivacaine in RS group and 5 ml/h of 0.5% ropivacaine containing 0.2 mcg/kg of dexmedetomidine in RD group. Arterial and central venous blood gas parameters were obtained 15 minutes after intubation during two lung ventilation (TLV15), 15 and 45 min after OLV (OLV15, OLV45) and 15 minutes after reinstitution of two lung ventilation (ReTLV).

Results:

RD group had better oxygenation (254.2 ± 72.3 mmHg, 240.60 ± 59.26 mmHg) as compared to RS group (215.2 ± 64.3 mmHg, 190.7 ± 61.48 mmHg) at OLV15 (P – 0.04) and OLV45 (P – 0.004) respectively. Shunt fraction in RD group was (30.31 ± 7.89%, 33.76 ± 8.89%) and (35.14 ± 7.58%, 39.57 ± 13.03%) in RS group at OLV15 and OLV45, respectively. The increase in the shunt fraction from TLV15 was significantly greater in RS group than RD group both at OLV15 (P – 0.03) and OLV45 (P – 0.03). The sevoflurane and fentanyl requirement was lower in RD group.

Conclusion:

Epidural dexmedetomidine improves oxygenation and reduces shunt fraction during OLV, in patients undergoing thoracotomy. It also reduces intraoperative anesthetic and analgesic requirement.

The effects of thoracic epidural analgesia on oxygenation and pulmonary shunt fraction during one-lung ventilation: an meta-analysis

BACKGROUND

The aim of our study is to compare the effects of thoracic epidural analgesia combined with general anesthesia (GA) vs. general anesthesia on oxygenation and pulmonary shunt fraction during one-lung ventilation (OLV).

METHODS

Literature research was firstly conducted for studies related to comparison of epidural anesthesia combined with GA vs. GA with reporting of hemodynamic and oxygenation variables and published from Jan 1990 to Jan 2014 in EMBAS, MEDLINE and Cochrane Central Register of Controlled Trials databases. The studies were reviewed and data were extracted and analyzed using fixed-effect and random-effect models.

RESULTS

There are 14 trials with 60 separate comparisons enrolling 653 patients for analysis. Regarding systemic hemodynamics, thoracic epidural analgesia decreased the mean arterial pressure and mean pulmonary arterial pressure with weighted mean difference 95% confidence interval (-6.64 [-9.57 to -3.71] vs. -6.33 [-9.25 to -3.41] and -3.18 [-5.07 to -1.28] vs. -2.05 [-3.35 to -0.75]) respectively at the two measurements time, however, only decreasing heart rate and systemic vascular resistance (-3.28 [-5.98 to -0.67] and -319.99 [-447.05 to -192.94]) over the first 30 min after OLV. For oxygenation variables, thoracic epidural analgesia is associated with significant reduction in partial arterial oxygen pressure, mixed arterial saturation of oxygenation and increased pulmonary venous admixture fraction compared to general anesthesia with weighted mean difference 95% confidence interval (-16.52 [-21.98 to - 11.05] vs. - 14.23 [-20.81 to - 7.65]), (0.74 [0.33 to 1.15] vs. - 0.63 [-1.23 to -0.04]) and (2.53 [1.35 to 3.72] vs. 2.77 [1.81 to 3.74]) respectively before and after 30 min of one-lung ventilation. A decrease in mixed venous saturation of oxygenation occurred after 30 min of OLV (-2.39 [-3.73 to -0.99]). Besides, a higher mean value of airway pressure was found in the thoracic epidural analgesia with weighted mean difference 95% confidence interval (1.95 [1.61 to 2.28] vs. 0.87 [0.54 to 1.20]) at the measurements.

CONCLUSION

Based on the existing limited data puts forward recommendations for cautious usage of thoracic epidural analgesia in case of underlying risks in lower systemic hemodynamics, decreased partial arterial oxygen pressure but increases pulmonary shunt during one-lung ventilation.

Flurbiprofen axetil increases arterial oxygen partial pressure by decreasing intrapulmonary shunt in patients undergoing one-lung ventilation

PURPOSES

In the present study, we investigated whether flurbiprofen axetil (FA) alleviates hypoxemia during one-lung ventilation (OLV) by reducing the pulmonary shunt/total perfusion (Q s/Q t) ratio, and examined the relationship between the Q s/Q t ratio and the thromboxane B2 (TXB2)/6-keto-prostaglandin F1α (6-K-PGF1α) ratio.

METHODS

Sixty patients undergoing esophageal resection for carcinoma were randomly assigned to groups F and C (n = 30 for each group). FA and placebo were administered i.v. 15 min before skin incision in groups F and C, respectively. The partial pressure of arterial oxygen (PaO2) was measured and the Q s/Q t ratio was calculated. Serum TXB2, 6-K-PGF1α, and endothelin (ET) were measured by radioimmunoassay. The relationship between TXB2/6-K-PGF1α and Q s/Q t was investigated.

RESULTS

Compared with group C, PaO2 was higher and the Q s/Q t ratio was lower during OLV in group F (P < 0.05). After treatment with FA, both serum TXB2 and 6-K-PGF1α decreased significantly (P < 0.05) but the TXB2/6-K-PGF1α ratio increased significantly (P < 0.01). Increases in the TXB2/6-K-PGF1α ratio were correlated with reductions in the Q s/Q t ratio during OLV in group F (r = -0.766, P < 0.01). There was no significant difference in serum ET between groups F and C.

CONCLUSIONS

Treatment with FA reduced the Q s/Q t ratio and further increased the PaO2 level during OLV, possibly due to upregulation of the vasoactive agent TXB2/6-K-PGF1α ratio.

Hypoxic pulmonary vasoconstriction: physiology and anesthetic implications

Hypoxic pulmonary vasoconstriction (HPV) represents a fundamental difference between the pulmonary and systemic circulations. HPV is active in utero, reducing pulmonary blood flow, and in adults helps to match regional ventilation and perfusion although it has little effect in healthy lungs. Many factors affect HPV including pH or PCO2, cardiac output, and several drugs, including antihypertensives. In patients with lung pathology and any patient having one-lung ventilation, HPV contributes to maintaining oxygenation, so anesthesiologists should be aware of the effects of anesthesia on this protective reflex. Intravenous anesthetic drugs have little effect on HPV, but it is attenuated by inhaled anesthetics, although less so with newer agents. The reflex is biphasic, and once the second phase becomes active after about an hour of hypoxia, this pulmonary vasoconstriction takes hours to reverse when normoxia returns. This has significant clinical implications for repeated periods of one-lung ventilation.

[Nonanalgesic effects of thoracic epidural anesthesia]

Thoracic epidural anesthesia, which has been performed since the 1950s, has progressed from being one analgesic technique among others to its present status as the technique of choice for managing pain after major abdominal and thoracic surgery. In addition to providing effective analgesia, the epidural infusion of local anesthetic agents produces a sympathetic block that offers advantages over other types of pain control, particularly with respect to the cardiovascular, respiratory, and gastrointestinal systems. Thoracic epidural anesthesia provides dynamic pain relief, allowing the patient to resume activity early. It also permits early extubation and is associated with fewer postoperative pulmonary complications, shorter duration of paralytic ileus, and a better response to the stress of anesthesia and surgery. However, meta-analyses have not yet demonstrated that postoperative outcomes are improved. This review describes the nonanalgesic effects of thoracic epidural anesthesia.

One-lung ventilation and arterial oxygenation

PURPOSE OF REVIEW

Hypoxemia during one-lung ventilation (OLV) has become less common; however, it may still occur in about 10% of cases. We review recent developments which may affect the incidence and treatment of hypoxemia during OLV.

RECENT FINDINGS

Changes in surgical techniques are affecting oxygenation during OLV. The increased use of the supine position may adversely affect the prevalence of hypoxemia, whereas the increased application of thoracoscopic techniques is limiting the treatment options. Treatment options such as global or selective recruitment maneuvers and drug effects of dexmedetomidine and epoprostenol on arterial oxygenation during OLV are discussed. Capnometry prior to, or early during OLV, may in fact be able to predict the degree of hypoxemia during OLV. Persistent controversies surrounding the effect of epidural anesthesia, ventilatory modalities and gravity are reviewed.

SUMMARY

Interesting concepts have emerged from case reports and small studies on the treatment and prediction of hypoxemia during OLV. Definitive studies on the most effective ventilatory mode remain elusive. End-organ effects of OLV are an exciting new concept that may shape clinical practice and research going forward.

Effect of epidural dexmedetomidine on intraoperative awareness and post-operative pain after one-lung ventilation

BACKGROUND

During combined general and regional anaesthesia, it is difficult to use autonomic signs to assess whether wakefulness is suppressed adequately. We compared the effects of a dexmedetomidine-bupivacaine mixture with plain bupivacaine for thoracic epidural anaesthesia on intraoperative awareness and analgesic benefits, when combined with superficial isoflurane anaesthesia (<0.05 maximum alveolar concentration) in patients undergoing thoracic surgery with one-lung ventilation (OLV).

METHODS

Fifty adult male patients were randomly assigned to receive either epidural dexmedetomidine 1 microg/kg with bupivacaine 0.5% (group D) or bupivacaine 0.5% alone (group B) after induction of general anaesthesia. Gasometric, haemodynamic and bispectral index values were recorded. Post-operative verbal rating score for pain and observer's assessment of alertness/sedation scale were determined by a blinded observer.

RESULTS

Dexmedetomidine reduced the use of supplementary fentanyl during surgery. Patients in group B consumed more analgesics and had higher pain scores after operation than patients of group D. The level of sedation was similar between the two groups in the ICU. Two patients (8%) in group B reported possible intraoperative awareness. There was a limited decrease in PaO2 at OLV in group D compared with group B (P<0.05).

CONCLUSION

In thoracic surgery with OLV, the use of epidural dexmedetomidine decreases the anaesthetic requirements significantly, prevents awareness during anaesthesia and improves intraoperative oxygenation and post-operative analgesia.

Airway catastrophes

PURPOSE OF REVIEW

The article reviews the epidemiology of airway injuries, airway anatomy, techniques for airway management, helpful pharmacologic adjuncts and finally alternatives to airway manipulation.

RECENT FINDINGS

Principles of airway management including the maintenance of spontaneous ventilation and careful and adequate preparation for an alternative plan will always be important. Advances in pharmacologic agents provide a safer, more controlled environment through which the patient's compromised airway can be controlled. Recent publications add to the evidence that alternative methods of oxygenation and ventilation such as cardiopulmonary bypass can be used successfully to treat patients with catastrophic airway injuries.

SUMMARY

Trauma to the airway, either blunt or penetrating or iatrogenic, can result in significant patient morbidity and mortality. Although, relatively rare, if we practice long enough, each of us will encounter such a patient. The anesthesiologist must be familiar with airway anatomy and the location of injury for successful treatment. Along with airway injuries, associated injuries are common and often complicate definitive airway treatment. Modern anesthetic medications such as dexmedetomidine and proven techniques such as awake fiberoptic intubation can be used to safely treat these difficult patients. Alternative therapies such as cricothyroidotomy and cardiopulmonary bypass should be available if first-line therapies fail to secure an injured airway.