Dynamic respiratory patterns after laparoscopic cholecystectomy

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.

The effects of different abdominal pressures on pulmonary function test results in laparoscopic cholecystectomy

This study aimed to examine the effects of differing intra-abdominal pressures on pulmonary function test results in laparoscopic cholecystectomy. Forty-five patients were operated on under 3 different intra-abdominal pressures: group A (8 mm Hg), group B (12 mm Hg), and group C (15 mm Hg). On the first day before and after the operation, forced vital capacity (FVC), forced expiratory volume in the first second (FEV1), FEV1/FVC rate, peak expiratory flow speed (PEF), and maximal middle expiration speed (FEF25-75) values were measured using Vmax 229 spirometry. No significant differences were observed among the 3 groups regarding preoperative and postoperative FVC, FEV1, FEV1/FVC, PEF, and FEF25-75 values (P=0.96, P=0.73, P=0.48, P=0.34, and P=0.33, respectively). When the groups' preoperative and postoperative values were compared, FVC, FEV1, and PEF values significantly decreased in each group. The FEF25-75 values statistically significantly decreased in groups B and C when compared with their preoperative values; however, the decrease in group A was not significant. In conclusion, different intra-abdominal pressures during laparoscopic cholecystectomy had similar effects on pulmonary function test results. However, lower intra-abdominal pressures were associated with slightly more negative effects on FEF25-75 values.

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.

[Recovery of lung function after laparoscopic cholecystectomy: the role of postoperative pain]

OBJECTIVES

Lung function has been shown to deteriorate after laparoscopic cholecystectomy (LC). The present study evaluated 1) the rate of recovery after LC, and 2) the pathogenic role of postoperative pain in functional deterioration.

DESIGN

Lung function was measured 24 hours before LC, upon hospital discharge (48-72 h after LC), and 10 days later. All patients received metamizol after LC until discharge (2 g every 6 h i.v.). Half the patients (analgesia group) received tramadol (150 mg i.m.) 30 minutes before lung function testing on the day of hospital discharge. The remaining patients constituted the control group.

PATIENTS

Twenty healthy subjects (53 4 years old) undergoing LC for gall bladder removal. All signed informed consent forms. Measures and outcomes: Patient characteristics and preoperative lung function results were similar in both groups. LC duration and postoperative course were also similar in both groups. All were discharged without complications within 72 hours after LC. Lung function upon discharge (FVC, FEV1, TLC, PaO2 and AaPO2) had deteriorated in both groups (p<0.001). Deterioration was less marked in the analgesia group (p < 0.05). Ten days later, lung function had normalized for all subjects.

CONCLUSIONS

These results indicate that after LC, 1) lung function is still abnormal when the patient is discharged from hospital, 2) lung function has fully recovered within 10 days, and 3) postoperative pain contributes significantly to temporary deterioration in lung function.

Effects of abdominal Co2 insufflation on renal and hepatic blood flows during acute hemorrhage in anesthetized pigs

OBJECTIVE

To evaluate the consequences of laparoscopy during hemorrhage, we studied the respiratory, renal, and hepatic blood flow changes induced by abdominal Co2 insufflation during severe hemorrhage in anesthetized pigs.

DESIGN

Prospective animal study.

SETTING

University research laboratory.

SUBJECTS

Anesthetized and ventilated pigs (n = 18).

INTERVENTIONS

The right carotid artery was cannulated to measure mean arterial pressure. A pulmonary artery catheter was inserted to measure mean pulmonary arterial pressure and cardiac output. After a midline abdominal incision, three flow probes were positioned around the portal vein, the hepatic artery, and the renal artery to measure portal vein blood flow, hepatic artery blood flow, and renal blood flow. To induce hemorrhage, blood was withdrawn until mean arterial pressure reached 50 mm Hg. Laparoscopy was mimicked by insufflating Co2 until intra-abdominal pressure reached approximately 15 mm Hg. Measurements were collected during hemorrhage, Co2 abdominal insufflation, and the combination of both interventions.

MEASUREMENTS AND MAIN RESULTS

Severe pulmonary hypertension and hypercapnic acidosis occurred during abdominal Co2 insufflation. However, the abdominal Co2 insufflation did not aggravate the cardiac output and total hepatic blood flow changes induced by acute hemorrhage, whereas the combination of hemorrhage and abdominal Co2 insufflation markedly altered renal blood flow.

CONCLUSIONS

These results suggest that renal function must be monitored carefully when performing laparoscopy in trauma patients. In contrast, hepatic perfusion seems well preserved.

Alterações funcionais respiratórias na colecistectomia por via laparoscópica

Objetivo: Estudar as alterações da ventilação e volumes pulmonares e da força muscular respiratória no pós-operatório de colecistectomia por via laparoscópica. Tipo de estudo: Estudo prospectivo. Material e métodos: Foram avaliados 20 pacientes provenientes da enfermaria de gastrocirurgia da Unifesp, com média de idade 42,7 anos, sendo 7 (35%) homens e 13 (65%) mulheres. No período pré-operatório todos foram submetidos a um questionário clínico, exame físico, radiografia de tórax, espirometria. No pré e no pós-operatório foram obtidas as medidas da força muscular respiratória (pressões inspiratória e expiratória máximas), da ventilação pulmonar (volume corrente e volume minuto), da capacidade vital, a oximetria de pulso e o índice diafragmático (ID). Este índice é capaz de refletir o movimento toracoabdominal, determinado pelas mudanças nas dimensões ântero-posteriores da caixa torácica (CT) e do abdome (AB) e foi calculado utilizando-se a seguinte fórmula: ID = D AB/D AB + D CT. Resultados: Observou-se que os pacientes evoluíram no primeiro dia de pós-operatório com diminuição média significante de 26% do volume corrente, de 645ml ± 220ml para 475ml ± 135ml; 20% do volume minuto, de 15,0L ± 4,5L para 11,9L ± 3,6L; 36% da capacidade vital, de 2,7L ± 0,6L para 1,74L ± 0,7L; 47% da pressão inspiratória máxima, de -75 ± -22cm/H2O para -40 ± 17cm/H2O; 39% da pressão expiratória máxima, de +90 ± 28cm/H2O para +55 ± 28cm/H2O e 36% do índice diafragmático, de 0,60 ± 0,10 para 0,39 ± 0,14 (p < 0,05). O volume corrente, o volume minuto e a pressão expiratória máxima retornaram aos seus valores basais no 3º dia de pós-operatório; a capacidade vital, pressão inspiratória máxima e o índice diafragmático retornaram aos seus valores basais entre o 4º e o 6º dia de pós-operatório. Dos vinte pacientes, somente um apresentou atelectasia como complicação pulmonar, tendo evoluído bem com as medidas habituais de fisioterapia respiratória. Conclusão: Concluímos que os pacientes submetidos à colecistectomia por via laparoscópica apresentam no 1º dia de pós-operatório diminuição significante dos volumes pulmonares e da força muscular respiratória. Porém, quando comparados com dados de literatura, o retorno aos valores pré-operatórios é mais rápido na cirurgia por via laparoscópica (3º e 4º dias de pós-operatório) do que na cirurgia abdominal convencional.

Effects of abdominal CO2 insufflation and changes of position on hepatic blood flow in anesthetized pigs

During surgical laparoscopy, total hepatic blood flow (THBF) may be modified by CO2 insufflation, changes of tilt, ventilation with high tidal volume, hypercapnia, and anesthesia, but little information is available on the THBF during the procedure. To investigate the changes of hepatic blood flow following the combination of abdominal CO2 insufflation and changes of tilt, we measured mean arterial pressure (MAP), cardiac output, portal vein blood flow (PVBF), and hepatic artery blood flow (HABF) in anesthetized and ventilated pigs. CO2 was insufflated in the abdomen [intra-abdominal pressure (IAP) approximately 15 mmHg], and the hepatic blood flow was measured in various positions (horizontal, 10 degrees and 20 degrees head down, and 10 degrees and 20 degrees head up) before and during CO2 insufflation. CO2 insufflation in the horizontal position did not modify MAP, cardiac output, or PVBF but increased HABF. The head-up tilt decreased MAP, cardiac output, and both hepatic flows in the absence of pneumoperitoneum, but in the presence of abdominal CO2 only cardiac output and PVBF were decreased. The head-down tilt increased MAP and THBF in the absence of pneumoperitoneum, whereas no change was observed in the presence of abdominal CO2. The combination of CO2 insufflation and changes of tilt was not deleterious to hepatic perfusion. These results suggest that hepatic blood flow may be preserved during surgical laparoscopy if the tilt does not exceed 20 degrees and if IAP after CO2 insufflation remains <15 mmHg.

A case-control study of postoperative pulmonary complications after laparoscopic and open cholecystectomy

Postoperative pulmonary complications (PPC) are common after upper abdominal surgery. The objective of this case-control study was to compare the incidence of PPC after laparoscopic cholecystectomy (LC) and open cholecystectomy (OC) within a tertiary care center. Patients were accrued from two sequential clinical trials that evaluated the role of incentive spirometry in the prevention of PPC after abdominal surgery. Included for study were patients with gallstones undergoing elective surgery who had an American Society of Anesthesiologists (ASA) classification < 3. All patients included in the study were encouraged to use an incentive spirometer at least 10 times each hour while awake. Patients with chronic bronchitis were excluded from study, as were patients who received other forms of physical therapy. OC was performed through either a transverse or an oblique incision. There was an equitable dispersion of putative risk factors for PPC between the groups at baseline. PPC were defined as clinical features consistent with collapse/consolidation, an otherwise unexplained temperature above 38 degrees C, plus either confirmatory chest radiology or positive sputum microbiology. The incidence of PPC was 2.7% (1/37) after LC and 17.2% (10/58) after OC (p < 0.05). It is concluded that PPC are less common after laparoscopic cholecystectomy than after open cholecystectomy.