Respiratory patterns after cholecystectomy. Effects of posture and CO2 stimulation

Effect of Thoracic Epidural Anesthesia in a Rat Model of Phrenic Motor Inhibition after Upper Abdominal Surgery

WHAT WE ALREADY KNOW ABOUT THIS TOPIC

WHAT THIS ARTICLE TELLS US THAT IS NEW: BACKGROUND:: One important example of impaired motor function after surgery is diaphragmatic dysfunction after upper abdominal surgery. In this study, the authors directly recorded efferent phrenic nerve activity and determined the effect of the upper abdominal incision. The authors hypothesized that phrenic motor output would be decreased after the upper abdominal incision; it was also hypothesized that blocking sensory input from the incision using thoracic epidural anesthesia would diminish this incision-induced change in phrenic motor activity.

METHODS

Efferent phrenic activity was recorded 1 h to 10 days after upper abdominal incision in urethane-anesthetized rats. Ventilatory parameters were measured in unanesthetized rats using whole-body plethysmography at multiple time points after incision. The authors then determined the effect of thoracic epidural anesthesia on phrenic nerve activity and ventilatory parameters after incision.

RESULTS

Phrenic motor output remained reduced by approximately 40% 1 h and 1 day after incision, but was not different from the sham group by postoperative day 10. One day after incision (n = 9), compared to sham-operated animals (n = 7), there was a significant decrease in spike frequency area-under-the-curve (median [interquartile range]: 54.0 [48.7 to 84.4] vs. 97.8 [88.7 to 130.3]; P = 0.0184), central respiratory rate (0.71 [0.63 to 0.79] vs. 0.86 [0.82 to 0.93]/s; P = 0.0460), and inspiratory-to-expiratory duration ratio (0.46 [0.44 to 0.55] vs. 0.78 [0.72 to 0.93]; P = 0.0023). Unlike humans, a decrease, not an increase, in breathing frequency has been observed after the abdominal incision in whole-body plethysmography. Thoracic epidural anesthesia attenuated the incision-induced changes in phrenic motor output and ventilatory parameters.

CONCLUSIONS

Upper abdominal incision decreased phrenic motor output and ventilatory parameters, and this incision-induced impairment was attenuated by thoracic epidural anesthesia. The authors' results provide direct evidence that afferent inputs from the upper abdominal incision induce reflex inhibition of phrenic motor activity.

Effects of laparoscopic cholecystectomy on lung function: A systematic review

AIM: To present and integrate findings of studies investigating the effects of laparoscopic cholecystectomy on various aspects of lung function.

METHODS: We extensively reviewed literature of the past 24 years concerning the effects of laparoscopic cholecystectomy in comparison to the open procedure on many aspects of lung function including spirometric values, arterial blood gases, respiratory muscle performance and aspects of breathing control, by critically analyzing physiopathologic interpretations and clinically important conclusions. A total of thirty-four articles were used to extract information for the meta-analysis concerning the impact of the laparoscopic procedure on lung function and respiratory physiopathology. The quality of the literature reviewed was evaluated by the number of their citations and the total impact factor of the corresponding journals. A fixed and random effect meta-analysis was used to estimate the pooled standardized mean difference of studied parameters for laparoscopic (LC) and open (OC) procedures. A crude comparison of the two methods using all available information was performed testing the postoperative values expressed as percentages of the preoperative ones using the Mann-Whitney two-sample test.

RESULTS: Most of the relevant studies have investigated and compared changes in spirometric parameters.The median percentage and interquartile range (IQR) of preoperative values in forced vital capacity (FVC), forced expiratory volume in 1 s and forced expiratory flow (FEF) at 25%-75% of FVC (FEF_25%-75%) expressed as percentage of their preoperative values 24 h after LC and OC were respectively as follows: [77.6 (73.0, 80.0) L vs 55.4 (50.0, 64.0) L, P < 0.001; 76.0 (72.3, 81.0) L vs 52.5 (50.0, 56.7) L, P < 0.001; and 78.8 (68.8, 80.9) L/s vs 60.0 (36.1, 66.1) L/s, P = 0.005]. Concerning arterial blood gases, partial pressure of oxygen [PaO₂ (kPa)] at 24 or 48 h after surgical treatment showed reductions that were significantly greater in OC compared with LC [LC median 1.0, IQR (0.6, 1.3); OC median 2.4, IQR (1.2, 2.6), P = 0.019]. Fewer studies have investigated the effect of LC on respiratory muscle performance showing less impact of this surgical method on maximal respiratory pressures (P < 0.01); and changes in the control of breathing after LC evidenced by increase in mean inspiratory impedance (P < 0.001) and minimal reduction of duty cycle (P = 0.01) compared with preoperative data.

CONCLUSION: Laparoscopic cholecystectomy seems to be associated with less postoperative derangement of lung function compared to the open procedure.

Laparoscopic vs. small incision cholecystectomy: Implications for pulmonary function and pain. A randomized clinical trial

BACKGROUND

Upper abdominal surgery, including laparoscopic cholecystectomy (LC), is associated with post-operative pulmonary dysfunction. LC has, by consensus, become the treatment of choice for symptomatic cholecystolithiasis. The small-incision cholecystectomy (SIC), a procedure which does not require a pneumoperitoneum threatens to be lost to clinical practice even though there is evidence of equality. We hypothesized that the SIC technique should be equal and might even be superior to the LC when considering post-operative pulmonary function due to the short incision length.

METHODS

A single-centre, randomized clinical trial was performed including patients scheduled for elective cholecystectomy. Pulmonary flow-volume curves were measured pre-operatively, post-operatively, and at follow up. Blood gas analyses were measured pre-operative, in the recovery phase and on post-operative day 1. Anaesthesia, analgesics, and peri-operative care were standardized by protocol. Post-operatively, patients and caregivers were blinded to the procedure.

RESULTS

A total of 257 patients were analysed. There was one pulmonary complication (pneumonia) in the LC group. In both groups, similar reductions of approximately 20% in pulmonary function parameters occurred, with complete recovery to pre-operative values. Patients in the SIC group consumed more analgesia when compared with the LC group without impact on blood gas analysis. Patients converted to a conventional open technique showed significant differences in six of the eight parameters in pulmonary function tests.

CONCLUSION

When evaluated with strict methodology and standardization of care, no clinically relevant differences were found between SIC and LC regarding pulmonary function. Our results suggest that the popularity of the laparoscopic technique cannot be attributed to pulmonary preservation.

Anaesthesiological considerations in small-incision and laparoscopic cholecystectomy in symptomatic cholecystolithiasis: implications for pulmonary function. A randomized clinical trial

BACKGROUND

Upper abdominal surgery, including laparoscopic cholecystectomy (LC), is associated with post-operative pulmonary dysfunction. LC has, by consensus, become the treatment of choice for symptomatic cholecystolithiasis. Small-incision cholecystectomy (SIC), a procedure that does not require a pneumoperitoneum, threatens to be lost to clinical practice, even though there is evidence of equality. We hypothesized that the SIC technique should be equal, and might even be superior, to LC when considering post-operative pulmonary function because of the short incision length.

METHODS

A single-centre randomized clinical trial was performed including patients scheduled for elective cholecystectomy. Pulmonary flow-volume curves were measured pre-operatively, post-operatively and at follow-up. Blood gas analyses were measured pre-operatively, in the recovery phase and on post-operative day 1. Anaesthesia, analgesics and peri-operative care were standardized by protocol. Post-operatively, patients and caregivers were blind to the procedure.

RESULTS

Two hundred and fifty-seven patients were analysed. There was one pulmonary complication (pneumonia) in the LC group. In both groups, similar reductions of approximately 20% in pulmonary function parameters occurred, with complete recovery to pre-operative values. Patients in the SIC group consumed more analgesia when compared with the LC group, without any impact on blood gas analysis. Patients converted to a conventional open technique showed significant differences in six of the eight parameters in pulmonary function tests.

CONCLUSION

When evaluated with strict methodology and standardization of care, no clinically relevant differences were found between SIC and LC with regard to pulmonary function. Our results suggest that the popularity of the laparoscopic technique cannot be attributed to pulmonary preservation.

Physiological responses to the early mobilisation of the intubated, ventilated abdominal surgery patient

The aim of this study was to investigate the effects of mobilisation on respiratory and haemodynamic variables in the intubated, ventilated abdominal surgical patient. Mobilisation was defined as the progression of activity from supine, to sitting over the edge of the bed, standing, walking on the spot for one minute, sitting out of bed initially, and sitting out of bed for 20 minutes. Seventeen patients with age (mean +/- SD) 71.4 +/- 7.1 years satisfied inclusion criteria. Respiratory and haemodynamic parameters were measured in each of the above positions and compared with supine. In the 15 subjects who completed the protocol, standing resulted in significant increases in minute ventilation (VE) from 15.1 +/- 3.1 l/min in supine to 21.3 +/- 3.6 l/min in standing (p < 0.001). The increase in VE in standing was achieved by significant increases in tidal volume (VT) from 712.7 +/- 172.8 ml to 883.4 +/- 196.3 ml (p = 0.008) and in respiratory rate (fR) from 21.4 +/- 5.0 breaths/min to 24.9 +/- 4.5 breaths/min (p = 0.03). No further increases were observed in these parameters beyond standing when activity was progressed to walking on the spot for one minute. When supine values were compared with walking on the spot for one minute, inspiratory flow rates (VT/TI) increased significantly from 683 +/- 131.8 ml/sec to 985.1 +/- 162.3 ml/sec (p = 0.001) with significant increases in rib cage displacement (p = 0.001) and no significant increase in abdominal displacement (p = 0.23). Arterial blood gases displayed no improvements following mobilisation. Changes in VT, fR, and VE were largely due to positional changes when moving from supine to standing.

Effects of posture on postoperative pulmonary function

BACKGROUND

Pulmonary morbidity is still a relevant complication to major surgery despite improvements in surgical technique and anaesthetic methods. Postoperative posture may be a pathogenic factor, but the effects of changes in postoperative posture on pulmonary function have not been reviewed.

METHODS

Review of controlled, clinical trials evaluating postoperative pulmonary function in patients positioned in the supine vs. the sitting or standing position and patients positioned in the supine vs. the lateral position. Data were obtained from a search in the Medline and Cochrane databases (1966 - August 2002) and manually searched bibliographies of the identified papers.

RESULTS

Eighteen papers met the inclusion criteria. Twelve studies evaluated the supine vs. the sitting or standing position and six studies evaluated the supine vs. the lateral position. Six of 12 studies found a positive effect on postoperative pulmonary function in the sitting or standing position compared with the supine. Thus, avoidance of the supine position may improve postoperative pulmonary function. Three of six studies showed a positive effect on postoperative pulmonary function of the lateral side compared with the supine. Thus, the lateral position has limited effects on pulmonary function.

CONCLUSION

Changes of postoperative position from supine to sitting or standing are of major importance in the interpretation of postoperative pulmonary outcome studies and in future strategies to improve pulmonary outcome.

Diaphragm kinetics during pneumatic belt respiratory assistance: a sonographic study in Duchenne muscular dystrophy

The principal aim of this study was to demonstrate the usefulness of M-mode sonography as a noninvasive technique to evaluate diaphragm excursion. The secondary aim was to assess the efficacy of pneumatic abdomino-diaphragmatic belt ventilation in patients with Duchenne muscular dystrophy. Using M-mode sonography, we measured the amplitude of diaphragm excursion in seven patients with Duchenne muscular dystrophy in various positions (0 degrees, 45 degrees, 75 degrees ) with and without pneumatic abdomino-diaphragmatic belt respiratory assistance. The belt significantly increased mean amplitude of diaphragm excursion by 62% at 45 degrees and by 55% at 75 degrees, and increased mean tidal volume by 43.5% at 45 degrees and by 49% at 75 degrees. Two patients were unable to tolerate the horizontal position (0 degrees ) During quiet breathing without the belt, amplitude of diaphragm excursion and tidal volume were positively correlated at 45 degrees (r=0.81; P=0.027) and 75 degrees (r=0.75; P=0.05). There was a significant intra-individual correlation between these two parameters during belt use but no inter-individual correlation. Without the belt, thoracic posture had no significant effect on amplitude of diaphragm excursion, either in quiet or deep breathing. After overnight respiratory assistance, arterial oxygen pressure and arterial oxygen saturation increased significantly, and arterial carbon dioxide pressure decreased from 52+/-6.4 to 46.4+/-4 mmHg. The pneumatic abdomino-diaphragmatic belt significantly improved gas exchanges and ventilation by increasing diaphragm excursion, as was clearly shown by noninvasive M-mode sonography. Indeed, M-mode sonography may be helpful in pneumatic abdomino-diaphragmatic belt pressure adjustment.

Breathing pattern and gas exchange in emergency and elective abdominal surgical patients

OBJECTIVE

To evaluate the effects of intra-abdominal surgical emergency on breathing pattern and gas exchange and compare it with the changes induced by elective abdominal surgery.

DESIGN

Prospective clinical study.

SETTING

Abdominal surgical departments in a university hospital.

PATIENTS

Patients operated for intra-abdominal emergency (n = 10, EAS), elective upper abdominal (n = 19, UAS).

MEASUREMENTS AND RESULTS

Breathing pattern and gas exchange were measured with a respiratory inductive plethysmograph and a gas exchange monitor. EAS patients had pre-operatively a classical rapid shallow breathing pattern and increased ventilatory demand due to increased energy expenditure. The operation improved the breathing to normal pattern (frequency, 26 +/- 5/min and 17 +/- 3/min, p < 0.01; tidal volume, 439 +/- 128 ml and 541 +/- 165 ml, NS., before and after surgery, respectively). Sighing was absent before and after EAS and strictly reduced after elective surgery (p < 0.01 for UAS). The operation restricted the abdominal-diaphragmatic breathing movement which was reflected as increased contribution of the rib cage to VT (%RC: from 37% +/- 15 to 57% +/- 15 for UAS p < 0.001; from 47% +/- 16 to 61% +/- 14 for EAS NS.). After EAS and UAS hypoxemia was common (p < 0.001) with frequent radiological pathology. We conclude that intra-abdominal surgical emergencies increase the ventilatory demand and challenge the respiratory system to marked adaptive changes both pre- and post-operatively.

Pulmonary function after cholecystectomy performed through Kocher's incision, a mini-incision, and laparoscopy

Comparative pulmonary function after cholecystectomy performed through Kocher's incision, a mini-incision, and laparoscopy was evaluated. Forty-five patients were randomly and prospectively divided into three groups of 15 each, depending on the surgical access employed. Forced vital capacity (FVC), forced expiratory volume at 1 second (FEV1), and forced expiratory flow at 25% to 75% (FEF25-75%) were determined 1 to 3 days before and 16 to 24 hours after cholecystectomy. The percent reduction of FVC (p = 0.0170), FEV1 (p = 0.0191), and FEF25-75% (p = 0.0045) was smaller after laparoscopic cholecystectomy than after Kocher's incision cholecystectomy. The percent reduction of FVC (p = 0.0170) was smaller after mini-incision cholecystectomy than after Kocher's incision cholecystectomy. There was no difference in the FEV1 (p = 0.0971) or FEF25-75% (p = 0.2058) between these two groups. FEF25-75% was significantly less impaired in the laparoscopic group than in the mini-incision group (p = 0.0327). No difference between these two groups was found in FVC (p = 0.5755) or FEV1 (p = 0.3952). It is concluded that postoperative pulmonary function is less impaired after laparoscopic cholecystectomy than after either mini-incision or Kocher's incision cholecystectomy.

Dynamic respiratory patterns after laparoscopic cholecystectomy

Important alterations in respiratory function have been observed after open cholecystectomy. These include a decrease in the abdominal tidal volume, forced vital capacity, and forced expiratory volume at 1 s. Laparoscopic cholecystectomy is a new procedure allowing removal of the gallbladder without a subcostal or midline incision. The result is less postoperative pain and earlier ambulation. This study sought to determine whether changes in rib cage and abdominal wall motion are different after laparoscopic than open cholecystectomy. Twelve otherwise healthy patients underwent respiratory inductive plethysmography prior to and one day after laparoscopic cholecystectomy. Frequency of resting breathing increased 29 percent after laparoscopic cholecystectomy (p = 0.03), while abdominal motion decreased 32 percent (p = 0.03). During coached abdominal breathing, rib cage tidal volume increased 70 percent (p = 0.005) and abdominal tidal volume decreased 29 percent (p = 0.01). These alterations in respiratory pattern after laparoscopic cholecystectomy were smaller in magnitude than those reported following the open procedure.