Respiratory effects of high thoracic epidural anaesthesia

Association between thoracic epidural anesthesia and driving pressure in adult patients undergoing elective major upper abdominal surgery: a randomized controlled trial

BACKGROUND

Thoracic epidural anesthesia (TEA) is associated with a knowledge gap regarding its mechanisms in lung protection and reduction of postoperative pulmonary complications (PPCs). Driving pressure (ΔP), an alternative indicator of alveolar strain, is closely linked to reduced PPCs with lower ΔP values. We aim to investigate whether TEA contributes to lung protection by lowering ΔP during mechanical ventilation.

METHODS

In this prospective, randomized, patient and evaluator-blinded parallel study, adult patients scheduled for elective major upper abdominal surgery were assigned to either the TEA group with combined thoracic epidural anesthesia and general anesthesia (TEA-GA) (n = 30) or the control group with only general anesthesia (GA) (n = 30).

MEASUREMENTS

The primary outcome was the minimum ΔP determined based on positive end-expiratory pressure (PEEP) after intubation. Secondary outcomes included the incidence of PPCs within seven days, the minimum ΔP at various time points, blood gas analysis, intensive care unit (ICU) admission rates, length of hospital stay, and 30-day mortality rate.

RESULTS

The TEA group had a significantly lower minimum ΔP titrated based on PEEP compared to the control group (11.23 ± 2.19 cmH2O vs. 12.67 ± 2.70 cmH2O; P = 0.028). Multivariate linear regression analysis showed that intraoperative TEA application (compared with its absence; unstandardized beta coefficient (B) = -1.289; P = 0.008) significantly correlated with ΔP. The incidence of PPCs did not differ significantly between the two groups (8 of 30 [26.7%] vs. 12 of 30 [40%]; P = 0.273), but the incidence of atelectasis in the TEA group was significantly lower than in the control group (5 of 30 [16.7%] vs. 12 of 30 [40.7%]; P = 0.012). Multivariate logistic regression analysis indicated that ΔP was the only variable significantly associated with PPCs (Adjusted Odds Ratio [OR] = 2.190; 95% Confidence Interval [CI]: 1.300 to 3.689; P = 0.003).

CONCLUSION

Compared to GA, TEA-GA can reduce intraoperative ΔP in patients undergoing major upper abdominal surgery, especially those undergoing laparoscopic surgery. However, compared to GA combined with ΔP-guided ventilation, TEA-GA combined with ΔP-guided ventilation does not reduce the risk of PPCs. There was no significant difference in the total use of various vasoactive drugs between the two groups.

TRIAL REGISTRATION

This study was registered in the Chinese Clinical Trial Registry (registration number ChiCTR2300068778 date of registration February 28, 2023).

Perioperative Pulmonary Atelectasis: Part II. Clinical Implications

The development of pulmonary atelectasis is common in the surgical patient. Pulmonary atelectasis can cause various degrees of gas exchange and respiratory mechanics impairment during and after surgery. In its most serious presentations, lung collapse could contribute to postoperative respiratory insufficiency, pneumonia, and worse overall clinical outcomes. A specific risk assessment is critical to allow clinicians to optimally choose the anesthetic technique, prepare appropriate monitoring, adapt the perioperative plan, and ensure the patient's safety. Bedside diagnosis and management have benefited from recent imaging advancements such as lung ultrasound and electrical impedance tomography, and monitoring such as esophageal manometry. Therapeutic management includes a broad range of interventions aimed at promoting lung recruitment. During general anesthesia, these strategies have consistently demonstrated their effectiveness in improving intraoperative oxygenation and respiratory compliance. Yet these same intraoperative strategies may fail to affect additional postoperative pulmonary outcomes. Specific attention to the postoperative period may be key for such outcome impact of lung expansion. Interventions such as noninvasive positive pressure ventilatory support may be beneficial in specific patients at high risk for pulmonary atelectasis (e.g., obese) or those with clinical presentations consistent with lung collapse (e.g., postoperative hypoxemia after abdominal and cardiothoracic surgeries). Preoperative interventions may open new opportunities to minimize perioperative lung collapse and prevent pulmonary complications. Knowledge of pathophysiologic mechanisms of atelectasis and their consequences in the healthy and diseased lung should provide the basis for current practice and help to stratify and match the intensity of selected interventions to clinical conditions.

A risk score for predicting postoperative complications in non-intubated thoracic surgery

Background

The risk factors for postoperative complications in non-intubated video-assisted thoracoscopic surgery (VATS) have not been observed before. Here to develop a simple risk score to predict the risk of postoperative complications for patients who scheduling non-intubated VATS, which is beneficial to guide the clinical interventions.

Methods

A total of 1,837 patients who underwent non-intubated VATS were included from January 2011 to December 2018. A development data set and a validation data set were allocated according to an approximate 3:2 ratio of total cases. The stepwise logistic regression was used to establish a risk score model, and the methods of bootstrap and split-sample were used for validation.

Results

Multivariable analysis revealed that the forced expiratory volume in the first second in percent of predicted, the anesthesia method, blood loss, surgical time, and preoperative neutrophil ratio were risk factors for postoperative complications. The risk score was established with these 5 factors, varied from 0 to 53, with the corresponding predicted probability of postoperative complications occurrence ranged from 1% to 92% and was calibrated (Hosmer-Lemeshow χ² =6.261; P=0.618). Good discrimination was acquired in the development and validation data sets (C-statistic 0.705 and 0.700). A positive correlation was between the risk score and postoperative complications (P for trend <0.01). Three levels of low-risk (0-15 points], moderate-risk (15-30 points], and high-risk (>30 points] were established based on the score distribution of postoperative complications.

Conclusions

This simple risk score model based on risk factors of postoperative complications can validly identify the high-risk patients with postoperative complications in the non-intubated VATS, and allow for early interventions.

Risk Factors for the Development of Intraoperative Hypoxia in Patients Undergoing Nonintubated Video-Assisted Thoracic Surgery: A Retrospective Study from a Single Center

Background

Nonintubated video-assisted thoracic surgery (NIVATS) has been demonstrated to be safe and effective in patients. However, the risk factors for intraoperative hypoxia are unclear. This retrospective study aimed to identify the risk factors for the development of intraoperative hypoxia in patients undergoing NIVATS.

Material/Methods

The study included patients who underwent NIVATS between January 2011 and December 2018. Intraoperative hypoxia was defined as SpO₂ ≤93%. Risk factors for hypoxia were identified by binary logistic regression analysis, and the characteristic distribution of patients with and without hypoxia was elaborated.

Results

Of 2742 included patients, age, anesthesia method, the technical level of surgeons, stair-climbing ability, and type of thoracic procedure were associated with intraoperative hypoxia (P<0.05). The characteristics of patients with hypoxia were older age (P=0.011), higher body mass index and revised cardiac risk index level (P=0.033 and P=0.031), and lower composition of stair-climbing ≥22 m (P<0.001). These patients also had more anatomical lung surgery and mediastinal mass resection (P=0.033) and more epidural anesthesia (P=0.005). The surgeries were more likely to be performed by surgeons with less than 10 years of VATS training (P=0.009) and to have increased intraoperative maximum end-expiratory carbon dioxide partial pressure (P<0.001). These patients had a longer Intensive Care Unit stay (P<0.001), duration of chest-tube drainage (P=0.019), and postoperative hospitalization (P=0.003).

Conclusions

The current study suggests that old age and stair-climbing ability of patients, anesthesia method, thoracic procedures, and surgeon experience are risk factors for intraoperative hypoxia in patients undergoing NIVATS.

[Thoracic epidural anesthesia for open cholecystectomy in severe lung disease. Description of a case and review of the literature]

The incidence of chronic obstructive pulmonary disease has increased in the last decade. The anesthetic management of these patients in upper abdomen surgery is a challenge to the anesthesiologist, since general anesthesia is associated with a high possibility of severe pulmonary complications. The search for a suitable alternative has been a subject of study for years. The case is presented of a patient with chronic obstructive pulmonary disease, who required an urgent cholecystectomy. The treatment of the case and brief review of the literature is presented.

VATS biopsy for undetermined interstitial lung disease under non-general anesthesia: comparison between uniportal approach under intercostal block vs. three-ports in epidural anesthesia

OBJECTIVE

Video-assisted thoracoscopic (VATS) biopsy is the gold standard to achieve diagnosis in undetermined interstitial lung disease (ILD). VATS lung biopsy can be performed under thoracic epidural anesthesia (TEA), or more recently under simple intercostal block. Comparative merits of the two procedures were analyzed.

METHODS

From January 2002 onwards, a total of 40 consecutive patients with undetermined ILD underwent VATS biopsy under non-general anesthesia. In the first 20 patients, the procedures were performed under TEA and in the last 20 with intercostal block through a unique access. Intraoperative and postoperative variables were retrospectively matched.

RESULTS

Two patients, one from each group, required shift to general anesthesia. There was no 30-day postoperative mortality and two cases of major morbidity, one for each group. Global operative time was shorter for operations performed under intercostal block (P=0.041). End-operation parameters significantly diverged between groups with better values in intercostal block group: one-second forced expiratory flow (P=0.026), forced vital capacity (P=0.017), oxygenation (P=0.038), PaCO2 (P=0.041) and central venous pressure (P=0.045). Intraoperative pain coverage was similar. Significant differences with better values in intercostal block group were also experienced in 24-hour postoperative quality of recovery-40 questionnaire (P=0.038), hospital stay (P=0.033) and economic expenses (P=0.038). Histology was concordant with radiologic diagnosis in 82.5% (33/40) of patients. Therapy was adjusted or modified in 21 patients (52.5%).

CONCLUSIONS

Uniportal VATS biopsies under intercostal block can provide better intraoperative and postoperative outcomes compared to TEA. They allow the indications for VATS biopsy in patients with undetermined ILD to be extended.

Is postoperative epidural analgesia better than patient-controlled analgesia for radical cystectomy?

Background:

The purpose of this study was to evaluate postoperative epidural analgesia (EPA) and intravenous patient-controlled analgesia (PCA) in terms of morbidity and mortality in patients undergoing radical cystectomy for bladder cancer.

Methods:

A retrospective study on patients undergoing radical cystectomy for clinical Tis-4N0M0 urothelial carcinoma of the bladder was performed. Patients were separated into two groups: primary EPA or PCA for postoperative analgesia. The surgical complication severity was determined according to the Clavien system. Mann-Whitney U tests, χ2 with Yates’ correction, or Fisher’s exact test were used. Predictive risk factors were explored using univariable and multivariable Cox regression models.

Results:

Of the 274 patients studied, 209 (76%) received EPA and 65 (24%) had PCA. Baseline balance was observed. Similar complication rates were observed between the EPA (36%) and PCA (34%) ( p=0.382). Patients greater than 70 years of age had more complications (35% vs 21%, p=0.002). PCA patients had higher rates of high-grade complications compared with EPA patients [40% vs 20% ( p=0.0007)]. Only age at time of surgery ( p=0.032) was associated with complications. Patients with pulmonary disease had a higher risk of complications ( p=0.001). EPA or PCA were not predictors for overall survival.

Conclusions:

There does not appear to be a significant difference in terms of morbidity or mortality between EPA and PCA following radical cystectomy (RC). Rare, catastrophic complications specific to EPA may occur. Standardized reporting of surgical complications is essential to compare studies and appropriately counsel patients.

Monitoring of vecuronium-induced neuromuscular blockade during one-lung ventilation

PURPOSE

We investigated the monitoring of neuromuscular blockade caused by vecuronium in patients receiving one-lung ventilation (OLV) anesthesia for lung surgery.

METHODS

Eighteen adult patients requiring OLV for lung surgery (OLV group) and 18 undergoing two-lung ventilation (TLV) for colon surgery (control group) were enrolled in this study. In the two groups, anesthesia was maintained with sevoflurane, fentanyl, and epidural lidocaine. Time from vecuronium 0.1 mg.kg(-1) to the onset of neuromuscular blockade; times to the return of T1, T2, T3, or T4 (the first, second, third, or fourth response of the train-of-four [TOF]); and recovery of T1/control or TOF ratio (T4/T1) were compared between the two groups.

RESULTS

Time to the onset of neuromuscular blockade in the OLV group was similar to that in the control group (289 +/- 74 vs 270 +/- 85 s [mean +/- SD]; P = 0.482). Times from vecuronium to the return of T1, T2, T3, or T4 in the OLV group did not significantly differ from those in the control group (21.9 +/- 7.0 vs 25.8 +/- 6.7 min for T1; P = 0.099). T1/control in the OLV group was significantly higher than that in the control group 50-120 min after vecuronium (P < 0.05). The TOF ratio did not differ significantly between the two groups.

CONCLUSION

During OLV for lung surgery, recovery of T1/control is accelerated in anesthetized patients receiving vecuronium.

Lung function after lobectomy: a randomized, double-blinded trial comparing thoracic epidural ropivacaine/sufentanil and intravenous morphine for patient-controlled analgesia

BACKGROUND

Although thoracic epidural analgesia (TEA) is considered superior to IV opioids for postoperative analgesia after thoracic surgery, a few studies clearly demonstrate an improvement in pulmonary function attributable to TEA using a local anesthetic in combination with an opioid.

METHODS

In this prospective, randomized, double-blind study, we compared the effects of TEA with ropivacaine and sufentanil (TEA group) to IV morphine (IV group), as they affected pain and pulmonary function after lobectomy in 68 patients. Pain intensity, forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), FEV1/FVC ratio, forced expiratory flows, and sniff nasal inspiratory pressure as a marker of inspiratory muscle strength were measured from the first to the fourth postoperative day.

RESULTS

Pain relief was better in the TEA group at rest and on coughing (P < 0.001). The impairment of FVC and FEV1 was less in the TEA group when compared with that in the IV group (P < 0.001 and P = 0.003, respectively). Sniff nasal inspiratory pressure, FEV1/FVC ratio, and expiratory flow values decreased similarly in both groups. In-hospital mortality, as well as postoperative pulmonary complications, was not different between groups.

CONCLUSION

After lobectomy, TEA enables a significant increase in pulmonary function concomitant with better pain relief than systemic morphine, although a modest intercostal motor block may occur.

Epidural anesthesia and pulmonary function

The epidural administration of local anesthetics can provide anesthesia without the need for respiratory support or mechanical ventilation. Nevertheless, because of the additional effects of epidural anesthesia on motor function and sympathetic innervation, epidural anesthesia does affect lung function. These effects, i.e., a reduction in vital capacity (VC) and forced expiratory volume in 1 s (FEV(1.0)), are negligible under lumbar and low thoracic epidural anesthesia. Going higher up the vertebral column, these effects can increase up to 20% or 30% of baseline. However, compared with postoperative lung function following abdominal or thoracic surgery without epidural anesthesia, these effects are so small that the beneficial effects still lead to an improvement in postoperative lung function. These results can be explained by an improvement in pain therapy and diaphragmatic function, and by early extubation. In chronic obstructive pulmonary disease (COPD) patients, the use of thoracic epidural anesthesia has raised concerns about respiratory insufficiency due to motor blockade, and the risk of bronchial constriction due to sympathetic blockade. However, even in patients with severe asthma, thoracic epidural anesthesia leads to a decrease of about 10% in VC and FEV(1.0) and no increase in bronchial reactivity. Overall, epidural administration of local anesthetics not only provides excellent anesthesia and analgesia but also improves postoperative outcome and reduces postoperative pulmonary complications compared with anesthesia and analgesia without epidural anesthesia.

Effect of obesity and thoracic epidural analgesia on perioperative spirometry

BACKGROUND

Lung volumes in obese patients are reduced significantly in the postoperative period. As the effect of different analgesic regimes on perioperative spirometric tests in obese patients has not yet been studied, we investigated the effect of thoracic epidural analgesia and conventional opioid-based analgesia on perioperative lung volumes measured by spirometry.

METHODS

Eighty-four patients having midline laparotomy for gynaecological procedures successfully completed the study. Premedication, anaesthesia and analgesia were standardized. The patients were given a free choice between epidural analgesia (EDA) (n=42) or opioids (n=42) for postoperative analgesia. We performed spirometry to measure vital capacity (VC), forced vital capacity, peak expiratory flow, mid-expiratory flow and forced expiratory volume in 1 s at preoperative assessment, 30-60 min after premedication and 20 min, 1 h, 3 h and 6 h after extubation.

RESULTS

Baseline values were all within the normal range. All perioperative spirometric values decreased significantly with increasing body mass index (BMI). The greatest reduction in VC occurred directly after extubation, but was less in the EDA group than in the opioid group: mean of -23(sd 8)% versus -30(12)% (P<0.001). In obese patients (BMI>30) the difference in VC was significantly more pronounced than in patients of normal weight (BMI<25): -45(10)% versus -33(4)% (P<0.001). Recovery of spirometric values was significantly quicker in patients receiving EDA, particularly in obese patients.

CONCLUSION

We conclude that EDA should be considered in obese patients undergoing midline laparotomy to improve postoperative spirometry.

Effects of high thoracic epidural anesthesia and local anesthetics on bronchial hyperreactivity

Bronchial hyperreactivity can cause life threatening bronchospasm after airway irritation. Therefore, endotracheal intubation is avoided in asthmatics when feasible. High thoracic epidural anesthesia can be used to avoid endotracheal intubation and offers less postoperative pulmonary complications when compared to systemic postoperative analgesia. However, there are concerns that it might also cause impaired ventilation by extended motor blockade, increased airway resistance, and increased bronchial reactivity because of pulmonary sympathicolysis. Nevertheless, high thoracic epidural anesthesia causes only a slight decrease in vital capacity and neither an increase in airway resistance nor increased bronchial reactivity. In fact, it causes a decrease in bronchial reactivity in patients with bronchial hyperreactivity mostly due to the systemic effect of the local anesthetic. The attenuation of bronchial hyperreactivity can be shown as a dose dependent effect of lidocaine and bupivacaine. The intravenous effect of lidocaine is comparable to the effect of a moderate dose of salbutamol and leads to an additive effect when both drugs are used in combination. Overall, high thoracic epidural anesthesia can be used safely in patients with bronchial hyperreactivity and intravenous administration of lidocaine (1.5-2.0 mg x kg(-1)) can be used as a prophylactic treatment prior to airway instrumentation.

Complications of neuraxial blockade

Epidural and spinal anesthesia enjoy wide usage in modern practice, and each can provide reliable and safe anesthesia. Although the techniques appear to the casual observer to require relatively straightforward technical skill, both are fraught with myriad hazards and potential complications. It is the familiarity with and the understanding of these complications that makes for safe and professional practice of these techniques.

Cardiovascular and pulmonary effects of epidural anaesthesia

Epidural anaesthesia has been used since the early 1900s. Consequently the general characteristics of these procedures have been well defined. More studies have provided a better understanding of the cardiopulmonary changes produced by epidural anaesthesia. The cardiovascular effects observed with epidural anaesthesia are complex and variable, depending on a multitude of factors. The extent of sympathetic denervation, balance of sympathetic and parasympathetic activity, the pharmacological effect of systemically absorbed local anaesthetic agents, inclusion of adrenaline in the anaesthetic solution, the distribution of blood in relation to cardiac filling and cardiovascular function of the patient must be taken into account when considering the circulatory effects of epidural anaesthesia. Individual cardiovascular response to different levels of sympathetic blockade varies widely, depending on the degree of sympathetic tone before the block. Epidural anaesthesia that is restricted to the level of the low thoracic and lumbar region (T5-L4) results in a "peripheral" sympathetic blockade with vascular dilatation in the pelvis and lower limbs. High thoracic epidural anaesthesia, from the first to fifth thoracic, blocks the cardiac afferent and efferent sympathetic fibres with loss of chronotropic and inotropic drive to the myocardium. Thoracic epidural anaesthesia appears to at least partly reverse the diaphragmatic dysfunction that is a major determinant of the decrease in lung volumes observed after upper abdominal surgery. This article summarizes cardiovascular and pulmonary responses to epidural anaesthesia. Details of clinical management are not included in the review.

Thoracic epidural analgesia as an adjunct to general anaesthesia for cardiac surgery. Effects on pulmonary mechanics

BACKGROUND

A lasting impairment of pulmonary function is common after cardiac surgery. Pain from the sternotomy may contribute to the impairment. Thoracic epidural analgesia (TEA) can efficiently relieve pain in the postoperative phase, but may also affect respiratory muscle function if local anaesthetics are used. We examined the effects of TEA on pulmonary function and ventilation at rest, before and after coronary artery bypass graft surgery (CABG).

METHODS

Thirty patients scheduled for CABG were randomized to receive either general anaesthesia alone or general anaesthesia with TEA. Before and after the operation the patients were examined by respiratory inductive plethysmography and spirometric tests.

RESULTS

Before the operation, TEA caused significant reductions in forced vital capacity (FVC), forced expired volume in 1 s (FEV1), maximal inspiratory (PImax) and expiratory (PEmax) pressure. The rib cage contribution to tidal volume decreased significantly but the co-ordination of the thoracic and abdominal movements remained essentially unaffected. Minute volume and respiratory frequency did not change significantly. On the first postoperative day a decrease in maximal breathing efforts was found in both groups. No differences between the groups in FVC, FEV1 and PImax were found, but PEmax was significantly greater in the TEA group. Despite the impairment, breathing at rest was largely normal in both groups.

CONCLUSIONS

A better pain-relief from TEA after CABG may improve the ability to cough by a greater expiratory muscle strength. FVC, FEV1, PImax and breathing at rest are not affected by TEA after cardiac surgery.

Thoracic epidural anesthesia as an adjunct to general anesthesia for cardiac surgery: effects on ventilation-perfusion relationships

OBJECTIVE

To determine the effects of thoracic epidural anesthesia (TEA) on ventilation-perfusion (VA/Q) relationships, atelectasis, and oxygenation before and after coronary artery bypass graft surgery (CABG).

DESIGN

Prospective, controlled, unblinded, randomized trial.

SETTING

Cardiothoracic clinic at a major university referral center.

PARTICIPANTS

Twenty-eight patients undergoing elective CABG.

INTERVENTIONS

Perioperative and postoperative TEA was added to general anesthesia (GA) in 14 patients, and 14 patients receiving GA alone served as controls.

MEASUREMENTS AND MAIN RESULTS

VA/Q relationships were measured by the multiple inert gas elimination technique, and, 20 hours postoperatively, atelectasis was assessed by computerized tomographic scans. Arterial and mixed venous blood gases and hemodynamic variables were measured by standard techniques. TEA per se caused no change in shunt, VA/Q matching, or oxygenation. Induction of GA in the control group and induction of TEA caused similar reductions in mean arterial pressure. The TEA patients needed less morphine analgesia postoperatively and were extubated earlier. Extubation caused significant improvement in VA/Q matching. On the first postoperative day, a slight reduction in PaCO2 was seen in the TEA group, but no differences in shunt, VA/Q matching, or oxygenation compared with the GA group. Both groups showed extensive bilateral atelectasis.

CONCLUSION

TEA can reduce respirator time and the need for morphine analgesics after CABG without negative effects on VA/Q matching, oxygenation, or atelectasis formation.

The effects of cervical epidural anesthesia with bupivacaine on pulmonary function in conscious patients

Cervical epidural anesthesia (CEA) can affect diaphragmatic function. We investigated the effects of CEA on the diaphragm muscle performance, breathing pattern, and respiratory drive of 10 healthy patients undergoing hand surgery before and after the administration of 0.25% and 0.375% bupivacaine. The lung volumes and flows, respiratory rate (RR), minute ventilation, respiratory cycle time, occlusion pressure, maximal inspiratory pressure (MIP), and hand grip strength were determined. ETCO2 and SpO2 were continuously monitored. The diaphragmatic excursion was evaluated using ultrasonography. Although CEA allowed painless hand rehabilitation, both 0.25% and 0.375% bupivacaine impaired diaphragmatic excursion, with values decreasing from 5.6 to 4.4 and 3.3 cm (P < 0.05), respectively, during forced sniff maneuvers. In the 0.25% and 0.375% bupivacaine groups, the values of MIP decreased from 74 to 56 and 44 cm H2O, forced vital capacity decreased from 3.8 to 3.2 and 2.8 L, and hand grip strength decreased from 43.3 to 27.8 and 20.5 kg force, respectively (P < 0.05). The tidal volume decreased from 0.8 to 0.6 and 0.5 L in the 0.25% and 0.375% bupivacaine groups, respectively, the RR increased from 14 to 18 breaths/min in both groups, and the occlusion pressure increased from 1.5 to 2.1 and 2.9 cm H2O in the 0.25% and 0.375% bupivacaine groups, respectively (P < 0.05). ETCO2 increased from 35.2 to 38.1 and 39.3 mm Hg in the 0.25% and 0.375% bupivacaine groups, respectively, and SpO2 decreased by 2% +/- 1% in the 0.375% bupivacaine group. CEA affects diaphragmatic function and the resulting lung volumes and MIP values. The observed alterations in breathing pattern and the significant increase in ventilatory drive may be caused by changes in the diaphragmatic muscle tension and an augmented CO2 load. In conclusion, we do not recommend this technique for routine postoperative hand rehabilitation using the studied bupivacaine concentrations.

IMPLICATIONS

We studied cervical epidural anesthesia in healthy patients undergoing hand surgery. The technique allowed painless rehabilitation but affected breathing pattern, diaphragmatic function, and respiratory drive. We cannot recommend this technique for routine clinical use.

Regional anaesthesia and cough effectiveness. A study in patients undergoing caesarean section

We report the results of a study of the effects of spinal and epidural anaesthesia for Caesarean section on commonly used indicators of a patient's ability to cough effectively. Both spinal and epidural anaesthesia, after the achievement of a block adequate for surgery, were associated with statistically significant decreases (p less than 0.05) in all the respiratory variables recorded: forced vital capacity, forced expiratory volume in one second, peak expiratory flow rate and maximum expiratory pressure. We conclude that although the observed changes are unlikely to impair the normal patient's ability to cough effectively in these circumstances, there may be clinically significant impairment in the presence of an inadvertently high block or in a patient with pre-existing pulmonary disease.

[Transient acute respiratory failure and thoracic epidural anesthesia]

A case is reported of acute respiratory failure occurring during upper abdominal surgery in a patient not previously known to have chronic respiratory failure. Preoperatively, this 68 year old patient presented with mild obesity, slight effort dyspnoea and paralysis of the right hemidiaphragm, a sequela of polytrauma she suffered the year before. Respiratory tests were not considered useful with regard to the results of clinical examination. Moreover, she had already several previous general anaesthetics without any problems. A thoracic epidural anaesthesia was performed with a mixture of 150 mg lidocaine, 37.5 mg bupivacaine with adrenaline and 100 micrograms fentanyl, injected in the T8-T9 epidural space via a catheter. Ten minutes after the starting of surgery, the patient became agitated and complained of difficulty in breathing. Blood gas analysis showed hypercapnia, with respiratory acidosis (Pao2: 28.19 kPa; Paco2: 9.2 kPa; pH 7.273). Clinical examination revealed a bilateral Horner syndrome (T1-T4 sympathetic blockade). The patient was intubated and ventilated after adequate sedation. She was extubated 3 h 30 min after the initial epidural injection. Epidural analgesia was maintained during 72 h, with 0.1% bupivacaine, with no recurrence of respiratory failure.