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

Effects of midline laparotomy on cough strength: a prospective study measuring cough pressure

BACKGROUND

Laparotomy is assumed to decrease cough strength due to three factors: abdominal muscle trauma, postoperative pain, and diaphragmatic dysfunction. However, the effect of trauma from laparotomy itself on strength (net of the other two factors) has not been measured to our knowledge. The aim of this study was to measure the effect of laparotomy on cough strength after first measuring the effect of epidural analgesia.

METHODS

In 11 patients scheduled for open midline laparotomy, cough pressure (PCOUGH), a proxy for strength, was measured with a rectal balloon at three moments: before the procedure, at baseline; before surgery, under epidural bupivacaine to T6; and postoperatively, under epidural bupivacaine to the same analgesic level (T6). Continuous variables were compared using the Wilcoxon signed-rank test. The repeatability of PCOUGH measurements was confirmed with the intraclass correlation coefficient (ICC). Pain on coughing, hand grip strength, and the Ramsay and modified Bromage scores were also recorded.

RESULTS

Median (interquartile range) PCOUGH decreased from a baseline of 103 (89-137) to 71 (56-116) cmH2O under presurgical epidural bupivacaine (P=0.003). Postoperative PCOUGH remained unchanged at 76 (46-85) cmH2O under epidural analgesia (P=0.131). The ICCs indicated excellent repeatability of the PCOUGH measurements (P<0.001). Pain on coughing was 0 to 1 in all subjects. Hand grip strength and the Ramsay and Bromage scores were unchanged.

CONCLUSIONS

Although thoracic epidural bupivacaine reduces cough strength as measured by PCOUGH, midline laparotomy does not further reduce strength in the presence of adequate epidural analgesia.

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.

Effects of bupivacaine versus levobupivacaine on pulmonary function in patients with chronic obstructive pulmonary disease undergoing urologic surgery: a randomized, double-blind, controlled trial

BACKGROUND

There are limited data to determine the impact of subarachnoid blockade with local anesthetics on perioperative pulmonary function. The effects of local anesthetics used in spinal anesthesia are very important in terms of respiratory function in patients with chronic obstructive pulmonary disease (COPD).

OBJECTIVE

The aim of this study was to evaluate the effects of bupivacaine versus levobupivacaine on pulmonary function in patients with COPD undergoing urologic surgery.

METHODS

Patients were randomized into 2 groups: group B (n = 25) received 3 mL of hyperbaric 0.5% bupivacaine; group L (n = 25) received 3 mL of isobaric 0.5% levobupivacaine. Both agents were administered intrathecally. Forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), peak expiratory flow rate (PEFR), vital capacity (VC), and FEV1/FVC ratio were measured using spirometry 10 and 30 minutes after spinal anesthesia and 30 minutes after completion of the operation. An arterial blood gas test was performed before and after spinal anesthesia.

RESULTS

Fifty male patients aged 40 to 80 years completed the study. There were no differences in the results of preoperative and postoperative FVC, FEV1, PEFR, VC, FEV1/FVC ratio, and arterial blood gas between the bupivacaine (n = 25) and levobupivacaine (n = 25) groups. However, patients who took bupivacaine showed a significant decrease in intraoperative PEFR at 30 minutes compared with baseline, a result not seen in patients who took levobupivacaine (P = 0.036 and P = 0.282, respectively).

CONCLUSIONS

In 50 patients with moderate COPD undergoing urologic surgery, hyperbaric bupivacaine caused a decrease in intraoperative PEFR compared with baseline because of higher level block; however, the effects of hyperbaric bupivacaine and isobaric levobupivacaine on pulmonary function in these patients showed equally effective potencies for spinal anesthesia.

A randomized controlled trial of auricular transcutaneous electrical nerve stimulation for managing posthysterectomy pain

Background. A patient- and assessor-blinded randomized controlled trial was conducted to examine the effectiveness of auricular transcutaneous electrical nerve stimulation (TENS) in relieving posthysterectomy pain. Method. Forty-eight women who had undergone a total abdominal hysterectomy were randomly assigned into three groups (n = 16 each) to receive either (i) auricular TENS to therapeutic points (the true TENS group), (ii) auricular TENS to inappropriate points (the sham TENS group), or (iii) 20 minutes of bed rest with no stimulation (the control group). The intervention was delivered about 24 hours after the operation. A visual analogue scale was used to assess pain while resting (VAS-rest) and upon huffing (VAS-huff) and coughing (VAS-cough), and the peak expiratory flow rate (PEFR) was assessed before and at 0, 15, and 30 minutes after the intervention. Result. As compared to the baseline, only the true TENS group reported a significant reduction in VAS-rest (P = .001), VAS-huff (P = .004), and VAS-cough (P = .001), while no significant reduction in any of the VAS scores was seen in the sham TENS group (all P > .05). In contrast, a small rising trend was observed in the VAS-rest and VAS-huff scores of the control group, while the VAS-cough score remained largely unchanged during the period of the study. A between-group comparison revealed that all three VAS scores of the true TENS group were significantly lower than those of the control group at 15 and 30 minutes after the intervention (all P < .02). No significant between-group difference was observed in PEFR at any point in time. Conclusion. A single session of auricular TENS applied at specific therapeutic points significantly reduced resting (VAS-rest) and movement-evoked pain (VAS-huff, VAS-cough), and the effects lasted for at least 30 minutes after the stimulation. The analgesic effects of auricular TENS appeared to be point specific and could not be attributed to the placebo effect alone. However, auricular TENS did not produce any significant improvement in the performance of PEFR.

Pulmonary effects of bupivacaine, ropivacaine, and levobupivacaine in parturients undergoing spinal anaesthesia for elective caesarean delivery: a randomised controlled study

BACKGROUND

Spinal anaesthesia is the method of choice for elective caesarean delivery, but has been reported to worsen dynamic pulmonary function when using bupivacaine. Similar investigations are lacking for ropivacaine and levobupivacaine. We have therefore compared the pulmonary effects of intrathecal bupivacaine, ropivacaine and levobupivacaine used for caesarean delivery.

METHODS

Forced vital capacity, forced expiratory volume in the first second, and peak expiratory flow rate were measured in 48 parturients before and after onset of spinal anaesthesia using either 0.5% bupivacaine 10 mg, 1% ropivacaine 20 mg, or 0.5% levobupivacaine 10 mg. Apgar scores and umbilical arterial pH were recorded.

RESULTS

The final level of sensory blockade was not different between groups. Forced vital capacity was significantly decreased with bupivacaine (3.6+/-0.5 L to 3.5+/-0.4 L, P<0.05) and ropivacaine (3.2+/-0.4 L to 3.1+/-0.5 L, P<0.05), but not with levobupivacaine (3.6+/-0.5 L to 3.4+/-0.6 L). Forced expiratory volume during the first second was not decreased in any group. Peak expiratory flow rate was significantly decreased with ropivacaine (5.5+/-1.5 L/s to 5.0+/-1.1 L/s, P<0.05) and levobupivacaine (from 6.0+/-1.1 L/s to 5.2+/-0.9 L/s, P<0.01). Neonatal vital parameters did not differ between the three groups.

CONCLUSIONS

Decreases in maternal pulmonary function tests were similar following spinal anaesthesia with bupivacaine, ropivacaine, or levobupivacaine for caesarean delivery. The clinical maternal and neonatal effects of these alterations appeared negligible.

The effect of spinal anaesthesia on urethral function

This study was to assess the effect of spinal anaesthesia on urethral retro-resistance pressure (URP), cough pressures and tendency to leak. The population consisted of 32 women undergoing a tension-free vaginal tape (TVT) operation under a spinal anaesthetic. URP, cough pressures and an assessment of the degree of leak were performed before the spinal anaesthetic was placed. A standard anaesthetic technique was used, and measurements were repeated after the spinal anaesthetic was inserted. The degree of leak was assessed on a five-point scale with 350 ml in the bladder. The cough pressures and URP values were averaged over three or more measurements. The mean URP value fell from 75.0 to 54.0 cm/H2O (p = 0.0003) after the spinal was inserted. There was a non-significant fall in mean cough pressure from 85.0 to 67.5 cm/H2O (p = 0.06). The degree of leakage increased (p = 0.005). Spinal anaesthesia causes a fall in the resistance in the urethra but does not cause a significant fall in the pressure generated by a cough. Women are more likely to leak after coughing during the TVT operation under spinal anaesthesia than they are before the spinal is inserted. The cough test under spinal anaesthesia does not mimic the result of coughing without a spinal.

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.

The effect of intrathecal fentanyl added to hyperbaric bupivacaine on maternal respiratory function during Cesarean section

BACKGROUND

Subarachnoid blockade with local anesthetics induces respiratory depression. Although the addition of fentanyl to bupivacaine has become popular in subarachnoid blockade for Cesarean section, there is no information on the effect of intrathecal fentanyl on maternal spirometric respiratory function in parturients undergoing Cesarean section.

METHODS

We tested the effect of the addition of intrathecal fentanyl to hyperbaric bupivacaine on maternal spirometric performance in 40 consenting parturients undergoing Cesarean section. The parturients were randomized into two groups: those receiving 2.0 ml of hyperbaric bupivacaine 0.5% and 0.4 ml of saline intrathecally and those receiving 2.0 ml of hyperbaric bupivacaine and 0.4 ml of fentanyl (20 microg) intrathecally. We performed spirometry on arriving at the operation room and 15 min after subarachnoid blockade.

RESULTS

Subarachnoid blockade with bupivacaine significantly decreased the peak expiratory flow rate, but did not induce significant changes in vital capacity and forced vital capacity. The addition of intrathecal fentanyl to bupivacaine improved the quality of subarachnoid blockade, but did not lead to a deterioration in respiratory function compared with intrathecal bupivacaine alone.

CONCLUSIONS

The addition of intrathecal fentanyl to hyperbaric bupivacaine did not lead to a deterioration in maternal spirometric respiratory function in parturients undergoing Cesarean section.

Impact of spinal anaesthesia on peri-operative lung volumes in obese and morbidly obese female patients*

Although obesity predisposes to postoperative pulmonary complications, data on the relationship between body mass index (BMI) and peri-operative respiratory performance are limited. We prospectively studied the impact of spinal anaesthesia, obesity and vaginal surgery on lung volumes measured by spirometry in 28 patients with BMI 30-40 kg.m(-2) and in 13 patients with BMI > or = 40 kg.m(-2). Vital capacity, forced vital capacity, forced expiratory volume in 1 s, mid-expiratory and peak expiratory flows were measured during the pre-operative visit (baseline), after effective spinal anaesthesia with premedication, and after the operation at 20 min, 1 h, 2 h, and 3 h (after mobilisation). Spinal anaesthesia and premedication were associated with a significant decrease in spirometric parameters. Spinal anaesthesia and premedication were associated with a significant decrease in spirometric parameters; mean (SD) vital capacities were - 19% (6.4) in patients with BMI 30-40 kg.m(-2) and - 33% (9.0) in patients with BMI > 40 kg.m(-2). The decrease of lung volumes remained constant for 2 h, whereas 3 h after the operation and after mobilisation, spirometric parameters significantly improved in all patients. This study showed that both spinal anaesthesia and obesity significantly impaired peri-operative respiratory function.

Impact of spinal anaesthesia and obesity on maternal respiratory function during elective Caesarean section*

Spinal anaesthesia for Caesarean section has gained widespread acceptance. We assessed the impact of spinal anaesthesia and body mass index (BMI) on spirometric performance. In this prospective study, we consecutively assessed 71 consenting parturients receiving spinal anaesthesia with hyperbaric bupivacaine and fentanyl for elective Caesarean section. We performed spirometry during the antepartum visit (baseline), immediately after spinal anaesthesia, 10-20 min, 1 h, 2 h after the operation, and after mobilisation (3 h). Baseline values were within normal ranges. There was a significant decrease in all spirometric parameters after effective spinal anaesthesia that persisted throughout the study period. The decrease in respiratory function was significantly greater in obese (BMI > 30 kg x m(-2)) than in normal-weight parturients (BMI < 25 kg x m(-2)), e.g. median (IQR) vital capacity directly after spinal anaesthesia; -24 (-16 to -31)% vs. -11 (-6 to -16)%, p < 0.001 and recovery was significantly slower. We conclude that both spinal anaesthesia and obesity significantly impair respiratory function in parturients.

Physiology of spinal anaesthesia and practical suggestions for successful spinal anaesthesia

There are numerous physiological effects of spinal anaesthesia. This chapter focuses on the physiological effects that are of clinical relevance to the anaesthesiologist, and provides suggestions for successful management of this simple and popular technique. The mechanisms and clinical significance of spinal-anaesthesia-induced hypotension, bradycardia and cardiac arrest are reviewed. The increasing popularity of ambulatory spinal anaesthesia requires knowledge that long-acting local anaesthetics, such as bupivacaine, impair the ability to void far longer than short-acting local anaesthetics, such as lidocaine. The importance of thermoregulation during spinal anaesthesia, and the clinical consequences of spinal-anaesthesia-induced hypothermia are reviewed. Effects of spinal anaesthesia on ventilatory mechanics are also highlighted. Lastly, the sedative and minimum-alveolar-concentration-sparing effects of spinal anaesthesia are discussed to reinforce the need for the judicious use of sedation in the perioperative setting.

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.

The efficacy and safety of the tension-free vaginal tape procedure do not depend on the method of analgesia

OBJECTIVE

The original tension-free vaginal tape (TVT) method, described by Ulmsten et al., routinely uses local anaesthesia during the procedure. Since the anaesthetic effect after local application of lidocaine hydrochloride was not always satisfactory we decided to introduce the spinal anaesthesia during this operation. The aim of the present study was to compare local and spinal anaesthesia with respect to their efficacy and safety in the TVT procedure.

METHODS

103 women, with objectively confirmed stress urinary incontinence, were randomised into the study. Sixty-seven women were anaesthetised locally and 36 patients spinally. All TVT procedures were performed as originally described. Objective assessment of the influence of anaesthesia on intra-abdominal pressure at rest and during the cough test was done using a rectal catheter and a central venous pressure manometer. The efficacy of the TVT procedure was based on a gynaecological examination with a cough test and a three-degree subjective scale: complete cure, improvement or failure.

RESULTS

The success of the TVT procedure performed under local anaesthesia is comparable with that achieved under spinal analgesia (p=0.42). The number of complications that occurred in the two groups does not differ significantly (p=0.57).

CONCLUSIONS

Spinal anaesthesia impairs the ability to cough effectively during the TVT procedure. However, the efficacy and safety of the operations performed under this type of anaesthesia are comparable with the efficacy and safety of operations done under local anaesthesia.

Subarachnoid block for a patient with progressive chronic inflammatory demyelinating polyneuropathy

IMPLICATIONS

We report a case of successful administration of a spinal anesthetic to a patient with progressive chronic inflammatory demyelinating polyneuropathy (CIDP). There have been no reports of regional anesthetic management of patients with CIDP.

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.

Respiratory effects of spinal anaesthesia for caesarean section

We report the changes observed in a number of pulmonary function tests performed on 36 patients undergoing Caesarean section under spinal anaesthesia. The tests comprised peak expiratory flow, forced expiratory volume in one second, forced vital capacity, forced expiratory volume in one second to forced vital capacity ratio and the maximal mid-expiratory flow. Significant changes occurred that are consistent with a restrictive ventilatory defect. These changes persisted for four hours after the induction of spinal anaesthesia. Administration of 35% oxygen by facemask failed to change significantly fetal umbilical vein pH or partial pressure of oxygen.

Pulmonary function changes during epidural anesthesia for cesarean delivery

Although changes in pulmonary function in parturients are documented, little is known about effects of regional anesthesia on these changes. This study was undertaken to determine if two local anesthetics, often used for epidural anesthesia for cesarean delivery, have different effects on pulmonary function testing. Nineteen ASA physical status I parturients undergoing elective cesarean delivery with epidural anesthesia were randomly assigned in double-blind fashion to receive either 0.5% bupivacaine or 2% lidocaine with epinephrine (1/200,000). Pulmonary function tests were measured using a calibrated spirometer with computer-recorded flow volume loops. Peak inspiratory pressure and peak inspiratory flow rate, peak expiratory pressure (PEP) and peak expiratory flow rate, forced vital capacity (FVC), and forced expiratory volume in 1 s (FEV1) were measured. Measurements were taken prior to epidural placement and at T-10 and T-4 levels. Peak inspiratory pressure, FEV1/FVC, FEV1, FVC, peak expiratory flow rate, and peak inspiratory flow rate did not differ from baseline in either group. Patients receiving lidocaine showed a significantly greater decrease in PEP at both T-10 and T-4 levels. Pep is largely dependent on abdominal musculature. If a denser motor block is provided by 2% lidocaine with epinephrine than by 0.5% bupivacaine, these muscles would be more affected, resulting in a greater decrease in PEP. These results may have implications regarding choice of local anesthetic for epidural anesthesia in parturients with some degree of respiratory compromise undergoing cesarean delivery.

Maternal respiratory function following normal vaginal delivery

Forced expiratory volume (FEV(1)) forced vital capacity (FVC), peak expiratory flow (PEF) and maximum expiratory pressure (P(E)max) were measured in 11 healthy women 2, 4, 8, 24, 48 and 72 hours after normal vaginal delivery and repeated after 6-8 weeks. There was a significant (P<0.05) reduction in the P(E)max up to 4 hours after delivery. In contrast, there was no significant reduction in FEV(1) or FVC at any of the time periods, and PEF showed a significant reduction only at 2 hours after delivery. This indicates that P(E)max is a more sensitive measure of respiratory muscle strength and that this is reduced for at least 4 hours after delivery. Any anaesthetic given during this period should take into consideration that the ability to cough effectively may be impaired.

Changes in pulmonary function tests during spinal anaesthesia for caesarean section

We report the changes in forced vital capacity, forced expiratory volume in 1 s, and peak expiratory flow rate during caesarean section under spinal anaesthesia, as indirect indices of the ability to cough effectively. There were progressive falls in forced expiratory volume in 1 s (FEV(1)), forced vital capacity (FVC) and peak expiratory flow rate (PEFR) from the onset of anaesthesia till the abdomen was open, with these results failing to return to pre-incision levels by the time the patient reached the recovery room. Although none of our patients complained of dyspnoea or difficulty in coughing such falls in PEFR and FEV(1) may lead to an inability to cough effectively or clear inhaled vomit especially in patients with previously impaired respiratory function.